Ecology and Evolutionary Biology

Sand verbena uses grains of sand to deter herbivores

Rachel Sauer — Thu, 19 Dec 2024 19:41:09 +0000

Sand verbena uses grains of sand to deter herbivores Rachel Sauer Thu, 12/19/2024 - 12:41

Jeff Mitton

Apparently, herbivores are not fond of chewing sandpaper

Sand verbena, Abronia fragrans, has a moth pollination syndrome, or a suite of floral characters modified by natural selection driven by moth pollination. Its flowers are open all night but closed all day, and long corolla tubes prevent bees from taking nectar but are ideal for moths with long tongues.

Moths follow plumes of floral fragrance from sand verbena until they are within sight of the bright, conspicuous white globes of 25 to 80 flowers, where they sip a nectar reward.

Although sand verbena has a large geographic range, it is limited to sandy habitats in Texas, New Mexico, Arizona, Utah, Colorado, Oklahoma, Kansas, Wyoming, Montana, Nebraska, South Dakota and North Dakota. While sand verbena is described as having white flowers that open only at night, populations in northern Texas and southwestern Oklahoma have a range of flower colors from light pink through fuchsia, and they also differ from most populations in the times that flowers open and close.

The plants with pink or fuchsia flowers remain open until late morning, and they reopen in early evening, allowing considerable visitation by bees and butterflies. Measurements of pollination success in the pink and fuchsia populations showed that diurnal or daytime pollination contributed 18% of the pollination success, in contrast to nothing at all in the remainder of the geographic range of the species.

Dwarf lupine with patches and particles of sand on its flowers, leaves and stem. (Photo: Jeff Mitton)

These data are consistent with the hypothesis that diurnal pollinators were a selective force producing and maintaining novel flower color and diurnal presentation of open flowers in the mornings and late afternoons. The long corolla tubes frustrate bee efforts to collect pollen or nectar but hold nectar available to virtually all butterflies.

Butterflies are visiting diurnally—the most common among them is the skipper Lerodea eufala, the Eufala skipper. These data and other observations suggest the hypothesis that the Eufala skipper applied selective pressure to change flower color from white to pink or fuchsia and to modify the times that flowers open and close.

How could a butterfly apply selection pressure? This terminology unintentionally suggests that the butterflies had a plan and the organization to apply it. But that was not the case. If some flowers did not close exactly at sunrise and if a small butterfly pollinated them, enhancing their seed set, the genes that influenced tardy closing of flowers would become more common in the next generation.

The butterfly did nothing more than sip nectar from a large globe of flowers, nor did the sand verbena do anything to achieve an intended goal. The metric of natural selection is the relative number of offspring produced by competing genotypes of sand verbena. Genes that had been rare produce more seeds, making those genes more common.

Sand verbena is in the genus Abronia, which has about 20 species, all in North and Central America. All thrive in sandy environments, and it is known that 14 of the 20 species have psammophory, a defense to herbivory that is more commonly called sand armor. The armor is assembled when wind-blown sandy grit adheres to sticky exudates on stems and leaves.

I first encountered psammophory when photographing dwarf lupine in the Maze in Canyonlands National Park, and since then I thought it was a rare defense. But a scientific article whose title begins with "Chewing sandpaper" lists more than 200 psammophorous species in 88 genera in 34 families.

Sand armor is not a rare defense; it is geographically widespread and has evolved many times. Experimental studies show that sand armor reduces herbivory—remove it from stems and leaves, and the plant suffers more herbivory than when the armor was intact. Add more sand, and the plant suffers less herbivory.

While sand verbena has a large geographic range, some species of Abronia have tiny geographic distributions. One example is Yellowstone sand verbena, A. ammophila, which is adapted to and endemic (found nowhere else) to the lake shores in Yellowstone National Park.

An obligate relationship was found recently when a new species of moth, Copablepharon fuscum, was discovered in 1995 on the shores of the Salish Sea between Georgia Straight and Puget Sound. The sand-verbena moth was found on just a few beaches and spits on Vancouver Island and Whidbey Island, and it only occupies sites with windblown sand and large and dense populations of A. latifolia, yellow sand verbena, which is found along Pacific Shores from Baja to British Columbia.

The sand-verbena moth uses yellow sand verbena as its host plant, meaning that it is the site of oviposition and the sole food consumed by the caterpillars. The caterpillars have specialized mouth parts allowing them to manipulate around grains of sand.

I know I will never see a sand verbena nor a dwarf lupine without the phrase "chewing sandpaper" popping into my thoughts.

Did you enjoy this article? Subscribe to our newsletter. Passionate about ecology and evolutionary biology? Show your support.

Apparently, herbivores are not fond of chewing sandpaper.

Traditional

White

Top image: Sand verbena usually presents white blooms but response to a pollinator can turn a population pink or fuchsia. (Photo: Jeff Mitton)

Cetacean science: A new understanding of humpback whale genetics

Rachel Sauer — Mon, 02 Dec 2024 16:44:47 +0000

Cetacean science: A new understanding of humpback whale genetics Rachel Sauer Mon, 12/02/2024 - 09:44

Blake Puscher

How a team of ��Ҵ�ý�ƽ�� PhD students produced the first chromosome-level reference genome for humpback whales

Humpback whales are striking animals, not only because of their size, but also because of their complex vocalizations, acrobatic swimming and thousand-mile migrations.

Moreover, they hold a vital role in marine ecosystems, as their fecal matter, which is released as floating plumes, fertilizes the upper layer of the ocean and stimulates the growth of the photosynthesizing plankton there. These plankton are the basis of the marine food chain and are major contributors to the global carbon cycle.

PhD student Maria-Vittoria Carminati worked with colleagues to create the first chromosome-level reference genome for humpback whales.

Despite the importance and charisma of humpback whales, research into the species has been limited by the lack of complete genetic information.

Maria-Vittoria Carminati, a PhD student in the University of Colorado Boulder Department of Ecology and Evolutionary Biology, changed this when, along with Associate Professor of Ecology and Evolutionary Biology Nolan Kane and a team of fellow graduate students*, she created the first chromosome-level reference genome for the species.

Moving the needle

Carminati became an attorney in 2008 and worked in that field until recently. “I came to the realization that I wanted to do something more meaningful with my brain power,” she says. “That’s why I switched to science: I thought it would allow me to make greater contributions to society.

“So, three years ago, I went back to college and got my bachelor’s in ecology and evolutionary biology.” After that, she started her PhD at ��Ҵ�ý�ƽ��. There remained the question of what she would do to “move the needle forward,” but Carminati knew it would probably involve the ocean.

“I’m a diver, I’m a dive instructor, I like to sail even though I’m not very good at it,” she continues. After seeing a humpback whale in person one day, she started reading about them and found a paper that mentioned they were splitting into different subspecies. “I thought the paper was trying its best, but I don’t think it had the tools it needed to be assertive about what it was saying.”

One of those tools is a reference genome. So, Carminati went to experiment.com for funding and to Cantata Bio for the sequencing. She got a permit to sequence the humpback DNA sample from the National Oceanic and Atmospheric Administration and obtained the sample itself from the National Institute of Standards and Technology.

The sample was from the kidney of an orphaned whale calf that was beached and died on the shore of Hawaii Kai.

Cantata Bio’s sequencing yielded half a terabyte of data, which Kane tasked a class to help Carminati process.

A humpback whale swimming off the coast of Moorea, French Polynesia. (Photo: Charles J. Sharp/Wikimedia Commons)

The basics of genome sequencing

Genome sequencing is the process scientists use to determine a large amount, if not the entirety, of an organism’s DNA, which is packaged in threadlike structures called chromosomes. Because the entire length of a chromosome cannot be sequenced at once, several strips are sequenced and then combined in what is known as a genome assembly.

The product of the researchers’ work is called a reference assembly. According to Carminati, this means that the chromosomes are represented well enough to be used in comparison with the DNA of other organisms. “It’s like having the full book of an organism’s DNA,” she says. “In our case, we are only missing 0.0003% of the entire genome.”

This level of accuracy distinguishes their assembly from others, such as the scaffold-level assembly of the humpback whale genome that already existed. To continue the book analogy, this level of assembly can be compared to a collection of passages that cannot be definitively ordered or associated with a particular “chapter,” or chromosome.

Such uncertainty is partially the result of short read lengths. “Short reads are cheaper, so often, labs will do short reads,” Carminati says. “The problem with a short read is that you are only getting, say, a couple of sentences from each page in the book.” These few sentences are less distinctive than longer passages, which leaves more doubt in the final genome assembly.

The DNA in the researchers’ assembly was created from long reads, which allows it to be organized into chromosomes. Their assembly also had a high depth, which is to say that reads were performed 30 times to ensure accuracy, consistent with the platinum standard introduced by Philip Morin of the Cetacean Genomes Project.

Insight and annotation

While this chromosome-level genome was created too recently for researchers to have made discoveries by using it, Carminati says that the resource can be expected to provide insights into interesting traits of humpback whales, such as their cell regulation, large size and cancer resistance, as well as the formation of subspecies and other elements of genetic variation.

A humpback whale breaches off the coast of Tahiti. (Photo: Jérémie Silvestro/Wikimedia Commons)

“We are right at the beginning of this process,” Carminati explains, “but the reason that you can start making those insights is because if you have a platinum-level assembly, you have a far greater degree of certainty of what genes are and are not there.” This will allow scientists to tell with certainty whether a gene exists, does not exist or exists and is expressed multiple times.

“That goes to cell regulation and cancer resistance,” Carminati says, “because, for example, if you have a lot of genes that relate to cell regulation, cell repair and cell control, that indicates a cancer-preventing or cancer-halting mechanism because cancer is the result of the misregulation of cell division.

“So, if you have multiple genes like this, that might be one way that these enormous, 40-ton creatures are able to get so big and have so much cell division but not develop cancer.”

Other insights could be provided by synteny analyses, which are comparisons between sets of chromosomes. According to Carminati, these comparisons can help identify conserved areas: regions of genes that are unlikely to be rearranged between generations. When genes are together in a conserved area, this could indicate that they work together or are necessary for each other’s function.

The researchers performed a synteny analysis between the chromosomes from the humpback whale reference genome and the chromosomes of a blue whale. Synteny analyses can also indicate evolutionary relationships, and their analysis showed that there is a high level of consistency in the evolutionary relationships between the two species.

They also used BUSCOs (benchmarking universal single-copy orthologs), which are genetic reference guides developed in Switzerland, to evaluate genome completeness. BUSCO genes for mammals correspond to common mammalian traits, Carminati says, like lactation, placentas and live births. This analysis showed high completeness, too, but also represents another possible application of the reference genome: comparing whales to other mammals.

“We said, ‘What genes within this mammal BUSCO reference list do both of these creatures [humpback and blue whales] have, but more interestingly, which ones do they not have?’” Spending more time with this sort of analysis in the future could provide information about the evolution of whales, since missing mammalian genes would have either served no purpose to whales or even been counterproductive.

Finally, the researchers asked Cantata Bio start to annotate the reference genome. “Annotation tells you what genes are where,” Carminati says, and it is a necessary part of genome analysis. The annotation has not been made public yet, since the process is ongoing.

However, the research has already drawn attention, since Carminati presented it at the International Marine Conservation Conference in Cape Town, South Africa, last month. “So,” Carminati says, “I went from seeing a humpback whale in Hawaii to presenting a genome in Cape Town. Four years ago, I was trying cases. It is a very surreal trajectory.”

*Contributing graduate students are Vlonjat Lonnie Gashi, Ruiqi Li, Daniel Jacob Klee, Sara Rose Padula, Ajay Manish Patel, Andy Dick Yee Tan and Jacqueline Mattos.

Did you enjoy this article? Subscribe to our newsletter. Passionate about ecology and evolutionary biology? Show your support.

How a team of ��Ҵ�ý�ƽ�� PhD students produced the first chromosome-level reference genome for humpback whales.

Traditional

White

Humpback whale with calf off Moorea, French Polynesia (Photo: Charles J. Sharp)

Trailing fleabane looks delicate, but it flowered through a drought

Rachel Sauer — Tue, 26 Nov 2024 23:13:46 +0000

Trailing fleabane looks delicate, but it flowered through a drought Rachel Sauer Tue, 11/26/2024 - 16:13

Jeff Mitton

Flower was once thought to repel fleas, a belief long-since debunked

According to the U.S. Drought Monitor, Boulder County was in severe drought in September and the beginning of October this year. On Oct. 14, I went up on Flagstaff Mountain to see what was blooming and to check the condition of some small cacti, Missouri foxtails.

The foxtails were shriveled and seemed to be shrinking into the earth, a common plight for cacti in drought conditions. But my attention quickly shifted to some delicate daisies—these were the only flowers blooming in the prolonged drought.

The flowering species was flowering was Erigeron flagellaris. The plants were about 8 inches tall and had the typical daisy bloom with numerous slender, white petals radiating from a central yellow disc. Erigeron is a large genus in the family Asteraceae, commonly called composites, because each of the blooms is a composite of yellow disc florets in the center and white ray florets radiating.

Each "petal" is a ray floret, a flower that is solely female and fertile. Each of the disc florets is bisexual and fertile. An E. flagellaris bloom has 40 to 125 ray florets and even more disc florets.

In addition to seeds produced by both ray and disc florets, E. flagellaris reproduces asexually by producing stolons, stems that grow horizontally, touching ground at each node.

Erigeron flagellaris, or trailing fleabane, flowers and their mature seeds (Photo: Jeff Mitton)

Contact with the ground stimulates a node to grow a new cluster of roots that support the growth of upright stems, leaves and more flowers. This asexual reproduction creates a spreading clone that, under the best of conditions, resembles a mat. The proliferation of stolons suggests its common names, trailing fleabane and whiplash fleabane. Strawberry plants also spread with stolons, but gardeners usually call them runners.

The genus Erigeron has about 200 species, many of them in North America and all with the common name fleabane. The name, originally from Old English and first used in 1548, comes from the belief that the plant's smell would repel fleas from a dwelling. Plants were either burned or hung in sachets. Both belief and practice were dispelled long ago—fleabanes do not banish fleas.

The Navajo were resourceful at finding preparations of plants that had practical uses for dyes and medicines, and they found a way to use the astringent properties released from crushed leaves of trailing fleabane. They would chew the leaves and then place the moist pulp directly on wounds to stop the bleeding.

Description of the scent of trailing fleabane is elusive. The website Southwest Colorado Wildflowers lists citations in which the scent has been described as spicy, camphor-like, ill-scented, mysterious and downright weird. Chemical studies of fleabanes shows that their fragrances come from essential oils, volatile liquids containing chemical compounds synthesized by the plant.

I was not able to find a study of the essential oil of trailing fleabane, but several other fleabanes have been studied, and all reveal a bewildering diversity of biologically active compounds. For example, a study of the essential oil in E. floribundus, which has the common names tall fleabane and asthma weed, has 85 biologically active compounds. Concentrations of the various compounds differ among fleabane species that have been studied, resulting in a diversity of fragrances.

The constituents in essential oils are undoubtedly expensive to synthesize, but many studies have shown that they contribute to the defense of the plant against herbivores, microbes and fungi. I see a parallel between the essential oils of fleabanes and the resins of pines, firs and spruces.

In fact, limonene is a component of both essential oils and resins. Laboratory studies have shown effective defensive activity of limonene in the oil of E. floribundus, and populations studies have shown that mountain pine beetles eschew ponderosa pines with high levels of limonene.

In summer months, as people camp, hike and generally play in the mountains, one often hears comments about the pleasant fragrance of stands of ponderosa pine, or a spruce and fir forest. But I have never noticed the smell of fleabanes. It is a certainty that herbivores such deer and rabbits note the smell and shun the plants; it is the primary defense of daisies.

The essential oils extracted from several fleabane species can be purchased on the web, but I am sure that sniffing a concentrated concoction of biologically active chemicals from a bottle and nasally inhaling in a field of fleabanes would be different experiences. Let's remember to go fleabane sniffing next summer.

Did you enjoy this article? Subscribe to our newsletter. Passionate about ecology and evolutionary biology? Show your support.

Flower was once thought to repel fleas, a belief long-since debunked.

Traditional

White

Trailing fleabane is small and appears delicate, but it is hardy and well defended. (Photo: Jeff Mitton)

What we don’t know about fungi could hurt us

Rachel Sauer — Wed, 20 Nov 2024 23:03:17 +0000

What we don’t know about fungi could hurt us Rachel Sauer Wed, 11/20/2024 - 16:03

Blake Puscher

��Ҵ�ý�ƽ�� researchers demonstrate how knowledge gaps hinder conservation efforts

Over the past century, conservationists have become more effective in sounding the alarm about species at risk of extinction. However, some groups, such as fungi, remain understudied, and the level of risk they face is unknown.

This isn’t because fungi are insignificant; according to the U.N. Decade on Restoration, fungi are important contributors to soil health and soil carbon sequestration, or the process of removing carbon dioxide from the atmosphere and storing it in soil. However, because so many fungi are poorly studied, the full extent of their contributions to global ecosystems remains unknown.

��Ҵ�ý�ƽ�� scientist Alisha Quandt and her research colleagues argue for the importance of closing taxonomical knowledge gaps related to fungi.

The importance of closing these gaps in taxonomical knowledge, or knowledge from the field of science concerned with the classification of organisms, are explained in a study by C. Alisha Quandt and Danny Haelewaters of the University of Colorado Boulder Department of Ecology and Evolutionary Biology, as well as colleagues from several European institutions.

In the study, Laboulbeniomycetes, a taxonomic class of fungi that either parasitize arthropods or use them for dispersal, represent fungi and understudied taxa generally.

Knowing what we don’t know

While there will always be some things that scientists don’t know, taking stock of knowledge gaps, or “shortfalls,” is necessary to correct these blind spots and avoid unjustified certainty. To this end, Quandt and her co-researchers created a list of gaps in ecological knowledge, specifically those that can hinder conservation efforts. These four types of gaps are the Linnean, Wallacean, Latimerian, and Scottian shortfalls.

The Linnean shortfall, named after Carl Linnaeus, father of modern taxonomy, is the difference between the number of species that exist and those that scientists have described, Quandt says. While many species of macro-organisms, and some groups in particular (such as birds) have been discovered and described, this is not true of micro-organisms and groups like fungi. As to the shortfall’s significance for conservation, Quandt continues, species that are unknown cannot be conserved.

The Wallacean shortfall, named after Alfred Russel Wallace, a biologist who was an early proponent of the theory of evolution, has to do with incomplete information on species’ geographical distribution, according to Quandt. “The example from our paper is a species of Herpomyces [a genus of fungi] that we know from the Northeast, Panama and an area in eastern Africa.” Since these places are distant and apparently unrelated, it is unlikely that this species occurs only in those places.

The Latimerian shortfall, named after Marjorie Courtenay-Latimer, a naturalist who rediscovered a supposedly long-extinct fish, is expressed as the number of species in a taxonomic group that may or may not be extinct, “because they haven't been seen or recorded officially, or even unofficially in some cases, for 50 or more years,” Quandt says. Fifty years may seem like a long time for an existing species to go unobserved, but the fish Latimer documented was thought to have been extinct since the discovery of its fossils in the prior century.

Finally, the Scottian shortfall, named after Sir Peter Markham Scott, founder of the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, is the difference between the number of described species in higher taxonomic groups (e.g., kingdom, phylum, class) and the number that have been assigned an IUCN classification. The IUCN is a global authority on the conservation status of various species, particularly via its Red List.

Why are some taxa understudied?

Laboulbeniales parasitic fungi growing on a Harmonia axyridis, or Asian ladybug. (Photo: Gilles San Martin)

There are several characteristics that make members of particular taxonomic groups difficult to study—they are often relatively uncommon, microscopic, lack distinctive form or do not grow in culture.

“There is a bias for scientists in general to describe things that are really common,” Quandt says. “So, things that many people are encountering on a regular basis get described sooner than rare taxa that you don't encounter that often.”

Of course, size plays into this, as does the lack of morphological traits: organisms the size of Laboulbeniomycetes will tend to go unnoticed even when they are encountered. For example, a fly agaric mushroom can be easily identified by its distinctive red-and-white cap, but the same is not true for the microscopic Laboulbeniomycetes.

The ability to grow cells in a cell culture—an artificial environment outside of a living organism—is similarly important, as it allows researchers to both manipulate and define the environment in which cells develop. This makes things that grow in culture easier to describe, Quandt says.

Another potential issue in poorly described taxa that Laboulbeniomycetes exemplifies is cryptic speciation. Cryptic speciation is when a new species forms without any traits that are clearly different from other species’.

Quandt gives an example: “The (study’s) first author, my former postdoc Danny Haelewaters, worked on one ladybug-associated taxon that people thought was one species because, morphologically, it looked like one thing; but when he was able to get samples from all over the globe, he used genetic data to separate them into separate clades, which he is now describing formally as individual species.”

There were morphological differences between the species, including size variation in some of their cells, but that sort of thing can be easily missed.

Knowledge shortfalls in Laboulbeniomycetes

In looking for the Linnean shortfall for Laboulbeniomycetes, the researchers first tried to use the class’ discovery curve data. Ideally, a discovery curve represents the gradually increasing number of discovered species within a group. However, this approach produced unrealistic results, likely because the species discovery curve data for Laboulbeniomycetes is flawed, as is typical in poorly studied taxa.

Laboulbeniales parasitic fungi growing on a Scaphidium quadrimaculatum, or shining fungus beetle. (Photo: Katja Schulz)

“One of the reasons that it's misleading for poorly studied taxa is because there are different rates of study for these groups,” Quandt says. For instance, certain specialist taxonomists may contribute significantly to the known number of species in a short time, creating a rapid increase in discoveries after several decades of little progress.

This “skewed specialist effect” isn’t the only problem with discovery curves of understudied taxa though, Quandt continues, since a species can become popular and receive a lot of study from different labs around the world. “This is like something my lab is working on: describing some new species related to the fungus that causes White Nose Syndrome of bats. Because that was just discovered in 2009, there has just been this exponential rise in the number of people studying it.”

So, while the lack of solid discovery curve data prevents a certain estimate of the Linnean shortfall, this proves the difficulty of creating conservation strategies for members of understudied taxa, as such strategies cannot be effectively applied to species that have not been found.

To examine the Wallacean shortfall, the researchers created a heatmap of reports of Laboulbeniomycetes species. This heatmap showed that the highest reported diversity existed in the United States, with several other unconnected hotspots around the world. Quandt says that this is likely the result of the geographical bias in field work and taxonomy toward North America and the northern hemisphere generally.

For example, many countries that have been characterized as megadiverse, such as Colombia and the Democratic Republic of the Congo, report very few species, and many in the southern hemisphere report zero. However, the presence of a single species in distant places without reports from intervening countries (e.g., Guatemala, Spain and Ukraine, but not in between) suggests a significant Wallacean shortfall.

This shortfall makes it hard to estimate a species’ range size, which is a major consideration in conservation assessments such as the Red List. It also interferes with the use of species distribution models, which are similarly important for conservation efforts targeting rare species.

The Latimerian shortfall for Laboulbeniomycetes was determined using species description dates and published records of species sightings. The researchers found that at least 71% of Laboulbeniomycetes species were not reliably observed after their initial description, and the last reliable observation was 50 or more years ago for 51% of species, compared to 1.7–3% for land-dwelling vertebrates.

The number of species that have not been seen for a long time is an issue for conservationists because it means that it is unknown whether these species are in danger of extinction or have already gone extinct.

As to the Scottian shortfall, not a single species of Laboulbeniomycetes has been assessed for the Red List. While less than 100%, the Scottian shortfall for all fungi is pronounced too, Quandt says, as “at the time we wrote this paper, there were only 625 Red List assessments for all fungi,” compared to 150,000 described fungal species, which is likely a vast underrepresentation according to an article in Fungal Diversity.

Stigmatomyces scaptomyzae fungi, a species of Laboulbeniomycetes, on a vinegar fly. (Photo: Katja Schulz)

This is important because the Red List is a significant tool for conservationists and, Quandt says, it is difficult to act to conserve a species if it hasn’t been assessed for its Red List status.

Addressing knowledge shortfalls

All of this raises the question of how gaps in scientists’ knowledge of microscopic and otherwise difficult-to-study species like Laboulbeniomycetes can be filled. Quandt and her research colleagues say that emerging technologies and trends in scientific data collection may help, and list several examples: DNA metabarcoding, environmental DNA analysis and citizen science.

“DNA metabarcoding is a way to use a barcode, which is a section of the DNA that is unique to a specific species, and sequence those regions of the DNA for all the organisms in that DNA sample,” Quandt explains. “So, if I took a gram of soil, and I extracted all the DNA from that soil, I could use the barcode to see which species of fungi are in that one gram of soil.”

Environmental DNA analysis is very similar, she continues, as it is also DNA that is sequenced from the environment. That “could be a gram of soil, it could be a leaf; but it's DNA that is not from a pure culture that we have in the lab, or from a fruiting body like a mushroom. It's a whole community of DNA from some environment.”

Both technologies could be useful for surveying understudied taxa, as their presence may not be immediately apparent but would show up in DNA analysis of soil or other places where they live.

Citizen science is a movement in which regular people help scientists by contributing data, Quandt says. One example of a citizen science platform is iNaturalist, whose website says that every user observation “can contribute to biodiversity science,” and that findings will be shared with a data infrastructure organization “to help scientists find and use your data.”

The data provided by citizen scientists are generally useful, but in particular might help correct the Wallacean and Latimerian shortfalls—at least in more easily observable species—as more people looking will yield more sightings, and these can be used to fill out information about a species’ geographical distribution and/or reduce uncertainty about whether it has gone extinct.

Most importantly, Quandt continues, “we're at an important moment in the fungal conservation movement. There's a lot of momentum right now, among my colleagues, to start pushing fungal conservation forward, and that's really different than when I started in the field 15 or more years ago.

“The big take home from this paper that we wrote is that we need to be mindful, as we have all this momentum towards trying to help push fungal conservation, that we don't leave behind some of these groups that are already understudied, and that we try to bring them in and help conserve them, and think about their conservation status, and also keep them in mind when we're talking about fungal conservation as a whole.”

Researchers Thomas Matthews, Joseph Wayman, Jonathan Cazabonne, Felix Heyman and Thomas Martin also contributed to this study.

Did you enjoy this article? Subscribe to our newsletter. Passionate about ecology and evolutionary biology? Show your support.

��Ҵ�ý�ƽ�� researchers demonstrate how knowledge gaps hinder conservation efforts.

Traditional

White

Top image: A Harmonia axyridis, or Asian ladybug, attacked by Laboulbeniales parasitic fungi (Photo: Gilles San Martin)

Fish on film: uncovering the environmental drivers of black spot syndrome

Rachel Sauer — Tue, 12 Nov 2024 17:18:32 +0000

Fish on film: uncovering the environmental drivers of black spot syndrome Rachel Sauer Tue, 11/12/2024 - 10:18

Blake Puscher

��Ҵ�ý�ƽ�� researchers use a unique, noninvasive method to determine the environmental factors contributing to several symptoms among tropical fish

For many researchers in biology and other natural sciences, dissecting specimens may not be desirable, though it is often necessary. This is because dissection means killing the animal a researcher is trying to study—a big issue, especially if the species is experiencing population decline.

Over time, such concerns have led scientists to develop a number of non-invasive techniques, including video transects. This is a type of video recording used in marine biology, in which divers film along a line of fixed length and depth to record images for computer-assisted analysis, obtain permanent data that can be reassessed later and survey wider areas in shorter amounts of time.

��Ҵ�ý�ƽ�� scientist Pieter Johnson and his research colleagues use a unique, noninvasive method to determine the environmental factors contributing to several symptoms among tropical fish.

A recently published study by Pieter Johnson, a University of Colorado Boulder professor of distinction in the Department of Ecology and Evolutionary Biology, and lead author Cheyenna de Wit of the University of Amsterdam, demonstrates the benefits of recording rather than dissecting specimens.

In their paper on black spot syndrome in ocean surgeonfish, the researchers use video transects to measure the severity of the disease among thousands of fish and identify the environmental factors contributing to its distribution.

What is black spot syndrome?

Black spot syndrome is a collection of several symptoms, the most prominent being the dermal lesions or spots for which the condition is named, according to Johnson. In many species, Johnson says, these lesions are black, “but in some species they’ll show up as white.” They form on the skin, scales and fins of fish.

The spots appear when the free-swimming, larval form of trematodes—commonly known as flukes, a type of parasitic flatworm—penetrate the skin of the fish and form cysts inside them. The distinctive coloration occurs when fish surround the cyst with melanin in response to the invasion, similar to the formation of pearls in oysters.

Relatively little is known about the genus of trematode that causes black spot syndrome, Scaphanocephalus. “Prior to us detecting it in 2017,” Johnson says, “it had never been reported from Caribbean fish. So, it was wholly undescribed from that area.” Much remains unknown about this trematode, including the type of snail that Scaphanocephalus infects before moving on to fish.

However, trematode infection is clearly very common in certain regions: In Johnson’s study, 70% of observed fish showed signs of infection, while a companion study of other Caribbean fish demonstrated both how high the parasite loads are in that region, and how many different fish species seem to be affected, according to Johnson.

As to the consequences of infection for fish, there is some evidence, Johnson says, that infected fish may graze less and have more trouble maintaining buoyancy. Researchers also hypothesize that they are more conspicuous to predators.

“One in particular, of course, is osprey, which are visual, fish-specialized predators that are looking for fish through the water,” Johnson says. “When these infected fish tend to flash or turn sideways, and you can see those black spots, it probably makes it a lot easier for the bird to detect them.”

If this hypothesis is true, black spot syndrome could bolster the numbers of the trematodes that cause it, as Johnson says osprey are their definitive host. That means these trematodes must enter the body of an osprey to reproduce. The transmission of the parasites is trophic, so they are passed along when infected fish are eaten.

Noninvasive methods

While black spot syndrome can have negative effects on infected fish, the most important consequences could be for reef ecosystems. According to Johnson, black spot syndrome has been increasingly prevalent in important herbivorous grazing fish in the Caribbean, such as surgeonfish and parrotfish.

Learn more

For more information on the complex lifecycles of digenetic trematodes, see this article about other research from CU involving the parasites.

“In tropical coral reef ecosystems,” Johnson explains, “surgeonfish and parrotfish, and other herbivores play a key role by grazing on algae.” Since infected fish are evidenced to graze less, and since they may be more likely to be eaten by osprey, the population of algae in the affected area can increase.

“Algae and coral are in a dynamic balance,” Johnson says, and if there is enough algal growth, “it can start to overwhelm and kill corals. So, in these areas, we try to keep those populations of surgeonfish and parrotfish as viable as possible, so that they can continue to regulate and graze down the algae.”

In fact, some studies have even said that grazing fish can help save coral reefs, with particular emphasis on parrotfish because the prior primary grazer in the Caribbean, spiny sea urchins, were killed off by disease in the 1980s. Also, trematode infection isn’t the only thing threatening surgeonfish and parrotfish populations, as they are popular catches for fisheries.

Because the fish being studied are ecologically important, it is particularly important to avoid interfering with their populations. Ordinarily, this is difficult, since dissection is the surest way to confirm a trematode infection—the parasites being clearly visible inside the fish’s bodies. In this case, though, the black spots characteristic of black spot syndrome allowed for a different approach: the video transect method.

To record as many surgeonfish as possible, and therefore provide an accurate estimate of how many fish were infected, SCUBA divers filmed at 35 sites along the coast of Curaçao, an island in the southern Caribbean. They recorded two and five meters below water for either 10 minutes or until 20 adult surgeonfish had been filmed.

An ocean surgeonfish with black spot syndrome. (Photo: Cheyenna de Wit)

Environmental factors

Besides determining that 70% of surgeonfish showed visible signs of black spot syndrome, Johnson and de Witt correlated different environmental factors with the severity of the syndrome, which they based on the average number of spots per fish.

One of the most significant effects the researchers observed arose from longitude—that is, the position of fish from east to west along the leeward (downwind) shore. Both the prevalence and intensity of black spot syndrome was lower toward the east and higher toward the west.

Johnson hypothesizes that this effect is caused by urban and industrial development, as the east end of Curaçao, where a portion of the research took place, is privately owned and less developed. The researchers observed the same association between development and infection intensity in Bonaire, the neighboring island.

The first component of the effect was wave intensity, which was negatively associated with infection intensity because the larval form of trematode that infects fish can’t swim well enough to overcome opposing tides. Wave energy is usually greatest at the eastern end of Curaçao, so this will have contributed to the lower intensity of infection at the east end.

The other components were positively associated with infection intensity. Nitrogen concentration increases with sewage and domestic runoff, which can contain nutrients and other pollutants. Nutrients can increase the population of trematode hosts, and pollutants can weaken the immune systems of fish that trematodes infect.

While fishing pressure can be either positively or negatively correlated with parasite abundance, Johnson says, this depends on the species involved. In the case of Scaphanocephalus, fishing pressure could increase abundance if it removed predatory fish from the environment, resulting in an increased snail population.

Student learning

��Ҵ�ý�ƽ�� students also play an important role in this research. Undergraduates in the field course Coral Reef Ecology and Conservation (EBIO 4090, taught by Johnson) spend their fall semester learning about coral reefs and the factors that threaten them before traveling to Curaçao over winter break. During a week-long SCUBA expedition, students learn how to collect video transect data using the same methods Johnson and his research colleagues use and are contributing valuable data to the understanding of black spot syndrome. For the upcoming trip, students will be revisiting some of the same sites as in the study to assess how black spot severity has changed through time, particularly following recent warm water bleaching events that have killed many corals.

Since most of the factors composing the difference between the east and west ends come from human action, it is possible that the severity of black spot syndrome could be significantly reduced if the handling of runoff and/or fishing behavior were changed.

A unique methodology

One noteworthy part of the way Johnson and de Witt’s study was conducted is that, with the videos collected, the researchers had observers record the number of lesions on each fish. This is unique, as prior studies have simply noted whether lesions were present, leaving the severity of infection uncertain.

Moreover, methods like the one used in this study may help to solve the challenges that come with observing ocean life. “There's a lot of ocean out there and not a tremendous number of people to study it,” Johnson explains, “so I think approaches like this could be applied in other areas where we're detecting blackspot syndrome.” Photos are an especially useful way to study the ocean because they are easy for anyone to take thanks to digital technology, he adds. For this reason, community science platforms like iNaturalist can be used to aggregate a large amount of data.

“When people are on vacation, or they’re diving, or they’re swimming,” Johnson says, “they upload all of their observations and fish photos, and we’ve been using that to scan across large sections of the Caribbean and lots of different fish species; and now some of the undergrads in the lab are also extending that to look into parts of the Indo-Pacific and other regions of the world where Scaphanocephalus occurs.

“So, I think those kinds of approaches, video transects and these community science-uploaded images, together start to give a much bigger picture of patterns of infection over large geographic areas.”

Did you enjoy this article? Subscribe to our newsletter. Passionate about ecology and evolutionary biology? Show your support.

��Ҵ�ý�ƽ�� researchers use a unique, noninvasive method to determine the environmental factors contributing to several symptoms among tropical fish.

Traditional

White

An ocean surgeonfish with black spot syndrome. (Photo: Cheyenna de Wit)

For some mammals, warming temperatures mean higher elevations

Anonymous — Tue, 15 Oct 2024 17:45:59 +0000

For some mammals, warming temperatures mean higher elevations Anonymous (not verified) Tue, 10/15/2024 - 11:45

In her Distinguished Research Lecture, ��Ҵ�ý�ƽ�� Professor Christy McCain will highlight how certain traits in some mammal and insect populations indicate who is at greatest risk from climate change

Colorado’s small, mountain-dwelling mammals are moving higher—not for better views or real estate, but because climate change is forcing them to.

This finding is based on a 13-year study of 27 rodent and four shrew species in Colorado’s Front Range and San Juan mountains—research that included trapping, tagging and releasing the various mammals to better understand their range.

While the findings are more complex than a simple trend of animals moving up the mountain, they spotlight the sobering possibility that climate change could force some mammals from Colorado entirely.

Christy McCain, a professor in the ��Ҵ�ý�ƽ�� Department of Ecology and Evolutionary Biology and curator of vertebrates in the CU Museum of Natural History, will discuss mountain biodiversity and climate change in her Distinguished Research Lecture Nov. 14.

“We’ve been talking about climate change in the Rockies for a long time, but I think we can say that this is a sign that things are now responding and responding quite drastically," Christy McCain, the study’s lead author, told Denver 7 in Feb. 2021.

McCain, a professor in the University of Colorado Boulder Department of Ecology and Evolutionary Biology and curator of vertebrates in the CU Museum of Natural History, uses mountains as natural experiments to study biodiversity, ecological theory, global change, montane ecology and range limits.

She will discuss mountain biodiversity and climate change in her Distinguished Research Lecture Nov. 14, highlighting the research her lab has done to understand how animals—mostly vertebrates and insects—are distributed on mountains around the world.

She and her research colleagues have found that different groups of animals, driven by their evolutionary history and climate, show distinctive patterns. For example, mountain biodiversity for rodents, salamanders and moths is quite different from birds, bats and reptiles.

The conservation priorities for each group of mountain organisms are closely tied to elevational diversity patterns, land-use change and complex interactions with a rapidly warming and drying climate. McCain will explore these topics through case studies of mammal populations in the Front Range and San Juan Mountains and carrion beetles—examining how various physiological traits like heat and desiccation tolerance may be critical to responses to climate change.

��Ҵ�ý�ƽ�� Christy McCain

McCain received dual bachelor’s degrees in wildlife biology and studio art from Humboldt State University, was a natural-resources and protected-areas specialist in the Peace Corps Honduras and earned her PhD in ecology and evolutionary biology from the University of Kansas.

She was a postdoctoral fellow at the National Center for Ecological Analysis and Synthesis at the University of California Santa Barbara before coming to ��Ҵ�ý�ƽ�� as an assistant professor in 2008.

If you go

What: 124th Distinguished Research Lecture, Mountain Biodiversity and Climate Change

Who: Professor Christy McCain of the Department of Ecology and Evolutionary Biology and CU Museum of Natural History

When: 4-5 p.m. Nov. 14, followed by a Q&A and reception

Where: Chancellor's Hall and Auditorium, Center for Academic Success and Engagement (CASE)

McCain studies how montane organisms are distributed on mountains around the world and how those populations and species are influenced by human land use and climate change. Her research spans topics across ecology and evolution to understand and conserve biodiversity.

Funded by the National Science Foundation through several grants, her research has appeared in more than 60 peer-reviewed journals, including Science, Ecology Letters, Ecology and Global Change Biology, among others.

McCain is the curator of vertebrate collections in the CU Museum of Natural History, where she is a steward for the continued protection and use of museum specimens for understanding and conserving the world’s biodiversity. Over the years, she has taught mammalogy as well as other topics in field biology, creative conservation messaging and mountain ecology and conservation.

��Ҵ�ý�ƽ�� the Distinguished Research Lectureship

The Distinguished Research Lectureship is among the highest honors given by faculty to a faculty colleague at CU Boulder. Each year, the Research and Innovation Office requests nominations from faculty for this award, and a faculty review panel recommends one or more faculty members as recipients.

The lectureship honors tenured faculty members, research professors (associate or full) or adjoint professors who have been with ��Ҵ�ý�ƽ�� for at least five years and are widely recognized for a distinguished body of academic or creative achievement and prominence, as well as contributions to the educational and service missions of CU Boulder. Each recipient typically gives a lecture in the fall or spring following selection and receives a $2,000 honorarium.

McCain and Jamie Nagle, a professor of physics, have been recognized with 2024-25 Distinguished Research Lectureships. Nagle will give his lecture Feb. 6, 2025.

Top image: Eli Allan/Unsplash

Did you enjoy this article? Subscribe to our newsletter. Passionate about ecology and evolutionary biology? Show your support.

Traditional

White

Samuel Ramsey receives the prestigious Lowell Thomas Award

Anonymous — Tue, 17 Sep 2024 19:26:37 +0000

Samuel Ramsey receives the prestigious Lowell Thomas Award Anonymous (not verified) Tue, 09/17/2024 - 13:26

Once frightened of insects, Ramsey has become a leader in the field of entomology

Samuel Ramsey, assistant professor of ecology and evolutionary biology at the University of Colorado Boulder, is one of this year’s recipients of the Lowell Thomas Award.

The Lowell Thomas Award, named after broadcast journalist and explorer Lowell Thomas and given by The Explorers Club, recognizes “excellence in domains or fields of exploration,” according to the award announcement. In particular, the award celebrates “individuals who have grit, tenacity, are undaunted by failure, and endure all obstacles, finding a way forward to discovery and results that expand the limits of knowledge.”

Samuel Ramsey (left) working with the chieftain of a hill tribe village in Thailand to sample domesticated bees for parasites. (Photo: Shin Arunrugstichai/Syzgy Media Co.)

Ramsey, also known as “your friendly neighborhood entomologist,” didn’t always like insects. They used to terrify him. But in the second grade he conquered his fears by learning about insects at his local library.

Now, more than 25 years later, Ramsey is one of the most innovative and distinguished thinkers in the field of entomology. His research has won him numerous awards, including first place in the International Three-Minute Thesis Competition, the American Bee Research Conference’s Award for Distinguished Research and the Acarological Society of America’s Highest Award for Advances in Acarology Research.

Ramsey—a member of the Explorers Club 50, class of 2024—also runs a nonprofit, the Ramsey Research Foundation, which seeks to protect pollinator diversity.

Ramsey’s fellow awardees this year are zoologist Carole Baldwin, ocean conservationist Ellen Pikitch and geothermal scientist Andrés Ruzo. Past recipients include Kathy Sullivan, E. O. Wilson, Kris Tompkins, Isaac Asimov, Sir Edmund Hillary and Carl Sagan.

The 2024 Lowell Thomas Awards Dinner takes place in Austin on Nov. 1.

Top image: Samuel Ramsey researching bee biodiversity in Thailand. (Photo: Shin Arunrugstichai/Syzgy Media Co.)

Did you enjoy this article? Subscribe to our newsletter. Passionate about ecology and evolutionary biology? Show your support.

Once frightened of insects, Ramsey has become a leader in the field of entomology.

Traditional

White

Studying complex networks of plants and pollinators

Anonymous — Wed, 11 Sep 2024 18:42:15 +0000

Studying complex networks of plants and pollinators Anonymous (not verified) Wed, 09/11/2024 - 12:42

Julian Resasco

I’ve visited the same Rocky Mountain subalpine meadow weekly for a decade of summers looking at plant-pollinator interactions—here’s what I learned

Imagine a bee crawling into a bright yellow flower.

This simple interaction is something you may have witnessed many times. It is also a crucial sign of the health of our environment—and one I’ve devoted hundreds of hours of field work observing.

Interactions between plants and pollinators help plants reproduce, support pollinator species like bees, butterflies and flies, and benefit both agricultural and natural ecosystems.

Julian Resasco is an assistant professor in the ��Ҵ�ý�ƽ�� Department of Ecology and Evolutionary Biology.

These one-on-one interactions occur within complex networks of plants and pollinators.

In my lab at the University of Colorado Boulder, we’re interested in how these networks change over time and how they respond to stressors like climate change. My team emphasizes long-term data collection in hopes of revealing trends that would otherwise be unnoticed.

Working at Elk Meadow

Ten years ago, I began working in Elk Meadow, which is located at 9,500 feet (or 2,900 meters) elevation at the University of Colorado’s Mountain Research Station.

I wanted a local field site that allowed for frequent observations to study the dynamics of plant-pollinator networks. This beautiful subalpine meadow, bursting with wildflowers and just 40 minutes from campus, fit the bill perfectly.

Since 2015, often joined by members of my lab, I have made weekly hikes to Elk Meadow. We visit from the first flower in May to the last in October. We observe pollinators visiting flowers at plots scattered throughout the meadow, walking the periphery to minimize trampling. The morning is the best time to visit because pollinator activity is high and thunderstorms often roll in at midday during the summer in the Rocky Mountains.

Observing the network

Elk Meadow is rich in biodiversity. Over the years, we have observed 7,612 interactions among over 1,038 unique pairs of species. These pairings were made by 310 species of pollinators and 45 species of plants.

Pollinators include not only a wide variety of bees, but also flies, butterflies, beetles and the occasional hummingbird. Expert entomologists help us identify some of the insects.

Plants include species that are widespread, like the common dandelion, and some that are only found in the Rocky Mountains, like the Colorado columbine.

Common but vital

Collecting data in Elk Meadow is fun, but it is also serious science. Our data is useful for understanding the dynamics of plant and pollinator interactions within and across seasons.

For example, we learned which interactions between plants and pollinators are stable and which change over time and space. We consistently observed interactions between generalist species and their many partners over time and in different plots across the meadow.

Generalist species can tolerate a range of environmental conditions, meaning they are more frequently available to interact.

In other words, generalist species are more likely to be alive, active and foraging in the case of pollinators—or flowering in the case of plants—compared with species that can only survive if environmental conditions like temperature, sunlight and rainfall are just right to support them.

Generalist species are vital in networks, but they often don’t receive the same conservation attention as rare species. Even these common species can decline due to environmental changes destabilizing entire ecosystems. Protecting these species is important for maintaining biodiversity.

Julian Resasco at Elk Meadows at ��Ҵ�ý�ƽ��'s Mountain Research Station. (Photo: Julian Resasco)

In it for the long term

As we gather more years of data, our study is becoming increasingly useful for understanding how networks and pollinator populations are changing—especially with signs of climate change increasingly emerging. Most ecological studies are only designed or funded for one or a few years, making our 10-year dataset one of only a few for plant-pollinator networks.

It is only with long-term ecological data that we can detect trends in responses to climate change, particularly because of high year-to-year variability in weather and populations.

The National Science Foundation supports a network of long-term ecological research stations across the U.S., including the Niwot Ridge Long-term Ecological Research Program near Elk Meadow, which is dedicated to the study of high-mountain species and ecosystems.

Colorado’s climate, like much of the world, is experiencing significant changes, such as rising temperatures, earlier snow melt and more late-winter and spring rain instead of snow. These changes lead to earlier water runoff from mountains, drier soils and more severe droughts. These shifts can have important consequences for plants and pollinators, including changes in where species are found, how many there are, and when they flower or forage.

High-elevation plant and pollinator communities may be especially vulnerable to climate change impacts since these areas are experiencing greater temperature increases compared with lower elevations.

We have seen warmer and drier conditions at Elk Meadow. Overlaid in this trend, we have observed annual variation in temperature and drought conditions that can help us understand and predict how different species will fare in a hotter and drier future.

Climate change is a driver of pollinator declines and is predicted to become increasingly important in the coming decades. Immediate threats also include pesticide use, light pollution and the destruction of wild habitats for farming and development.

The state of Colorado recently commissioned a study to gauge the health of Colorado’s native pollinators and make recommendations on how to protect them.

Appreciating the current pollinator landscape

Working at Elk Meadow has provided opportunities for my students to conduct independent research and receive valuable training and mentoring.

Seeing the beauty of the living things in the meadow and observing their cycles inspires my students and me.

Elk Meadow is a place to clear my mind and come up with new research ideas. It is also a place to observe and record how one tiny patch of our planet is changing in reaction to bigger changes happening around it.

Julian Resasco is an assistant professor in the Department of Ecology and Evolutionary Biology at the University of Colorado Boulder.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

I’ve visited the same Rocky Mountain subalpine meadow weekly for a decade of summers looking at plant-pollinator interactions—here’s what I learned

Traditional

White

Sphinx moth caterpillars wield an eruptive defense

Anonymous — Thu, 29 Aug 2024 18:21:43 +0000

Sphinx moth caterpillars wield an eruptive defense Anonymous (not verified) Thu, 08/29/2024 - 12:21

Jeff Mitton

Sphinx months have an array of identifiers, one being an unusual defense mechanism

Cindy Burkhardt Maynard had been watching a sphinx moth caterpillar in her garden for several days, but then, it disappeared. Soon after, she saw another trundling across a dirt road on Rabbit Mountain. These were Hyles lineata white-lined sphinx moths which are the most common in this area. As caterpillars progress through 5 developmental stages or instars, their colors and patterns change. In addition, their background colors change from dark green in eastern states to light green in the mountains west to yellow in California. Due to this variability, it can be difficult to identify sphinx moth species from the caterpillar stage alone.

Color patterns of white-lined sphinx moth caterpillars vary with age and geography. Photos by Cindy Burkhardt Maynard.

A caterpillar transforms into a colorful moth with a heavy body about 3 inches long and a wingspan of about 4 inches. Against a brown background, the wings and body have stripes and zones of black, white and salmon or pink.

You may have seen hawkmoths but mistaken them for hummingbirds. Hummingbirds and hawkmoths are about the same size, both are active at dusk and both hover while taking nectar from flowers. Sphinx moths can fly up to 30 mph and while hovering they beat their wings 41 cycles per second (up and down), so fast that they make a buzzing sound.

If I am not thinking critically, the plight of a sphinx caterpillar evokes my sympathy. Imagine—a very large, soft caterpillar that does not bite or sting, devoid of poisonous spines and urticating (barbed) hairs, unable to fly or run away. Admittedly, the colors and patterns of some sphinx moths provide camouflage, but if they cross a road or path or patch of sand, the camouflage fails them. The sphinx caterpillars are also called hornworms due to an ominous, threatening horn projecting upwards from their posterior end, but it is all bluff--the horn is harmless.

Caterpillars of many butterfly species consume plants that have toxic defensive chemicals, which they sequester to specific tissues, such as fat tissues. Predators quickly learn that these caterpillars are toxic and thus inedible. However, the sphinx moths do not either transport or sequester plant molecular defenses. They utilize plant molecular defenses but with another technique.

Endoparasite pupae spill from a sphinx moth puparium.

If a predator approaches a sphinx caterpillar, the caterpillar rears its head in an unmistakably threatening way. If the predator persists and approaches closer, the caterpillar engages in projectile vomiting, spewing a fetid slop of semi-digested food laced with the toxic compounds synthesized by the plants it was eating. The predator, now drenched with a stinking and stinging slime and probably suffering impaired vision and sense of smell, would likely lose its concentration and break off its attack.

Even if all predators can be dissuaded, the caterpillar faces more challenges. A large number of wasps and flies are endoparasitic, meaning that the adult female injects an egg beneath the skin of a caterpillar. If you have ever been stung by a wasp, you know that the wasp can sting while swooping by, without landing. Endoparasitic species may insert one or many eggs, dooming the caterpillar. Endoparasites remind me of "Alien" a horror sci-fi movie that appeared in 1979.

A neighbor was removing a lilac bush when he found a sphinx pupa. After completing all of its instars, it had burrowed into the roots of the lilac and transformed into a pupa. My neighbor showed me the pupa, and we agreed that I would give it loving care so that we could identify the species when the moth emerged as an adult. Neither of us was aware of the load of endosymbiont eggs that were embedded in the pupa. In late summer, too much time had passed, and I knew something was wrong. I cracked open the puparium and endosymbiont pupae spilled out. They had completely consumed all the moths, leaving the sphinx puparium fully packed with endosymbiont pupae.

To identify the species of endosymbiont, I took the capsules to the laboratory of Deane Bowers, a CU entomologist whose lab could rear the endosymbionts. But the endosymbionts were dead and thus unidentified, so I am unable to end this story as I had hoped.

I mentioned that I had sympathy for sphinx moths for they had few defenses against a horde of enemies and thus each had a low probability of surviving to reproduce. An adult female sphinx moth can lay up to 1,000 eggs, but if her population is neither shrinking nor expanding, the average number of eggs that survive to reproduce is two, one for herself and one for her mate. Sphinx moths run a gauntlet to complete their life cycle, but this is the way it is for all species.

Top photo: A sphinx moth hovers while choosing its next nectar source.

Did you enjoy this article? Subscribe to our newsletter. Passionate about ecology and evolutionary biology? Show your support.

Sphinx months have an array of identifiers, one being an unusual defense mechanism.

Traditional

White

Mountain ball cactus has variation in floral color and scent

Anonymous — Wed, 03 Jul 2024 15:15:18 +0000

Mountain ball cactus has variation in floral color and scent Anonymous (not verified) Wed, 07/03/2024 - 09:15

Jeff Mitton

Lingering question: Do variations in scent correspond to variations in color?

Spring weather in Boulder is difficult to predict because it seems that it is not a time of gradual warming but rather alternating days of summer and winter.

Meyers Gulch, with an elevation of 7,350 feet in the Boulder County Open Space and Mountain Parks, is a fine place to see the first flowers of spring in a highly variable environment. Notable among the earliest blooming flowers are pasque flower and mountain ball cactus, Pediocactus simpsonii.

Scanning through my photos of blooming mountain ball cactus (hereafter MBC) I was surprised to find one photo taken in March and most photos taken in late April—in many years MBC present flowers while it is snowing. Another testimony to its hardiness is that it occurs at the highest elevations of any cactus in North America. It is found from 4,600 to 11,500 feet in elevation, and it grows in places known to have winter temperatures that plunge far below zero degrees Fahrenheit.

MBC has a wide geographic distribution, and it grows in a diverse set of plant communities. It is native to Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, South Dakota and Utah, where it is found in prairie grasslands, piñon-juniper woodlands, sagebrush and coniferous forests.

Among all these places and habitats, MBC exhibits such a bewildering amount of variation that biologists have described 13 subspecies, most of which do not withstand critical scrutiny—only three subspecies are commonly recognized.

One of the examples of extreme variation was described by Dr. Elzada Clover, known for describing new species of cacti during the first botanical expedition through the Grand Canyon in 1938. A few years later, she reported that MBC might be two species based on growth form. The cacti growing on Monarch Pass in Colorado use somatic growth to form densely packed mounds of 25 to 30 balls, each with a diameter of 1 to 2 inches. Just down the road, around Gunnison, MBC grow as singletons reaching 6 inches in diameter.

Floral color variation caught my eye. The flowers that I have encountered in the Front Range are rich magenta, but in other localities the flowers can be white, pink, yellow, or yellow-green. Colorado National Monument has white flowers, Malta, Idaho, has bright yellow flowers.

Mountain ball cactus grow as single balls or mounds of balls produced by vegetative reproduction. (Photos: Jeff Mitton)

Katherine Darrow, in Wild ��Ҵ�ý�ƽ�� Wildflowers, reports lovely pink flowers near Crested Butte, and Al Schneider notes white, pink and yellow flowers in his website Southwest Colorado Wildflowers.

I was unable to find any publications describing geographic or environmental patterns for these flower colors. Surely different colors thrive in xeric piñon-juniper woodlands at low elevations with long growing seasons versus moist coniferous forests with short growing seasons high in the mountains.

Some evolutionary biologists would propose that this is neutral genetic variation, meaning that the alternate flower colors have no consequences that influence any component of life history, such as growth, development, reproduction or survival, that would influence variation in reproductive success. That is, natural selection does not influence flower color and it plays no role in adaptation.

I had found an account that described bright yellow MBC in Malta, Idaho, and it mentioned that they have a lemon fragrance. In Wild about Wildflowers, I read Katherine Darrow's description of pink flowers with a rose fragrance. This covariation of floral colors and fragrance suggests that the key to the floral variation is in the discipline of pollination biology, and it reminded me of important and relevant work

Candace Galen has worked systematically to examine the consequences of floral scent variation in sky pilot, Polemonium viscosum at Pennsylvania Mountain Natural Area west of Fairplay. Sky pilots have variation in floral fragrance and size of the blooms, and these characters covary to adapt sky pilots to their heterogeneous environments.

Individual plants can produce either a sweet fragrance from large blooms or a skunky fragrance from relatively small blooms. Sweet fragrances attract predominantly bumble bee queens, which are nicely accommodated by large blooms. Small flies, seeking rotting flesh or feces, are drawn to skunky fragrances from small blooms. Flies are more reliable pollinators in the low temperatures at high elevations, so sky pilots emitting skunky smells increase with elevation.

This fruitful research program shows that floral fragrance and size can favor different pollinators, and these relationships can vary with elevation, gender of the pollinator and drought versus normal conditions. I see some similarities between sky pilots and MBC.

Will MBC be found to have floral scent and color variation adapting cacti to a wide variety of pollinators and plant communities throughout a large geographic range? Perhaps a first step would be to determine the degree to which floral fragrance differs with flower color.

Will pink (rose fragrance) and yellow (lemon scent) flowers always have the same fragrance? Will pollinators vary among the flower colors? Will the other colors—magenta, white and yellow-green—have their own distinct fragrances? I deeply regret never sniffing the magenta flowers in the Front Range.

Did you enjoy this article? Subscribe to our newsletter. Passionate about ecology and evolutionary biology? Show your support.

Lingering question: Do variations in scent correspond to variations in color?

Traditional

White

Ecology and Evolutionary Biology

Sand verbena uses grains of sand to deter herbivores

Related Articles

Cetacean science: A new understanding of humpback whale genetics

Related Articles

Trailing fleabane looks delicate, but it flowered through a drought

Related Articles

What we don’t know about fungi could hurt us

Related Articles

Fish on film: uncovering the environmental drivers of black spot syndrome

Related Articles

For some mammals, warming temperatures mean higher elevations

Related Articles

Samuel Ramsey receives the prestigious Lowell Thomas Award

Related Articles

Studying complex networks of plants and pollinators

Related Articles

Sphinx moth caterpillars wield an eruptive defense

Related Articles

Mountain ball cactus has variation in floral color and scent

Related Articles