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June 4, 2021 by wpengine

Collected on this Day in 1982: One specimen isn’t always enough!

Archiving biological variation.

by Mason Heberling

Five herbarium sheets with specimens of trillium on them arranged with the smallest leaves on the left and largest on the right.

This specimen is not a specimen but a set of five specimens! Same species (large flowered trillium, Trillium grandiflorum). Same site (in Somerset county, PA). All collected on same date (June 4, 1982) by Frederick H. Utech and Masashi Ohara.

We know that one specimen of every species is not enough. Having many specimens of many species, across many sites, and through time are necessary to document what organisms lived where, when, how far species ranges extend, and how these change through time. We study these specimens to understand biodiversity and biodiversity change across many scales.

But why collect that many vouchers of the same species, from the same site, on same date? One reason might be to send “duplicate” vouchers to other herbaria, both to help other collections expand their holdings, to get expert opinions on identification, and/or to protect against (unlikely but very possible) damage that may happen in one herbarium (like fire, flood, insect damage – oh my!).

But that isn’t what happened here. All specimens are stored together at Carnegie Museum of Natural History.

Voucher series of trillium herbarium specimen sheets.

So why? Well, it is simple, but quite genius, really. Utech and Ohara collected a “life history” voucher series. That is, these specimens each show different stages of the species’ development from small cotyledon-bearing seedlings just germinating above ground, to one leaved plants, to small to large three leaved juvenile trilliums that have not yet flowered, to large adult plants with flowers.

Utech and Ohara, along with Shoichi Kawano, pioneered this method of collecting and advocated for its importance in a 1984 essay in the Journal of Phytogeography and Taxonomy. Historically, plant specimens are collected with a major specific purpose in mind – to document the plant was there at a given time. To do that, botanists of course collect specimens that are best for identification, such that others can verify the species. For most species, that means plants tend to be collected when they are adults and reproductive (with flowers and/or fruits). Specimens without reproductive organs (called “vegetative” specimens) are generally viewed as less useful for this purpose and often avoided.

But Utech and others found that this standard approach, though useful for some research, did not cut it for their work. As organismal biologists studying the life history, ecology, and life cycle of species, they found many species were not well represented in herbarium collections.

Many species, like trillium, have distinct life stages from seedling to juvenile to adult. Many species form overwintering leaves or juvenile leaves that differ dramatically, even unrecognizably, from “typical” adult specimens.

So there’s good reasons to collect across life history and across individuals within a population. Biological collections are all about archiving biodiversity in its many forms, whether across deep time with fossils, across species, within species, or even within populations at a specific site.

Man at a table of plant specimens talking to a child about them. — Dr. Frederick H. Utech, past curator at Carnegie Museum, at a member’s night in 1979.

Dr. Utech (1943-2021) was a curator at the museum from 1976 until 1999. He was then a research botanist at the nearby Hunt Institute for Botanical Documentation until his retirement in 2011, notably contributing to three volumes of the Flora of North America project. More than 23 thousand specimens in the Carnegie Museum herbarium were collected by him. Dr. Utech passed away earlier this year but his legacy lives on. You can find his obituary here.

Inspired by the method of life history series and the need for new perspectives in the way we collect, CMNH Botany staff are working to promote and expand these ideas. We are presenting some of these ideas at the Society of Herbarium Curators annual meeting later this summer.

Find many more specimens (24,662 to be exact!) collected by Dr. Utech (including other life history series vouchers) here.

Check back for more! Botanists at the Carnegie Museum of Natural History share digital specimens from the herbarium on dates they were collected. They are in the midst of a three-year project to digitize nearly 190,000 plant specimens collected in the region, making images and other data publicly available online. This effort is part of the Mid-Atlantic Megalopolis Project (mamdigitization.org), a network of thirteen herbaria spanning the densely populated urban corridor from Washington, D.C. to New York City to achieve a greater understanding of our urban areas, including the unique industrial and environmental history of the greater Pittsburgh region. This project is made possible by the National Science Foundation under grant no. 1801022.

Mason Heberling is Assistant Curator of Botany at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Leaping Slugs! Did that Slug Just Jump?

by Timothy A. Pearce

Some species of slugs and snails can thrash their tail from side to side, twitching with such vigor that the creatures seem to jump. In some cases, they can become airborne briefly. I don’t know whether this behavior can properly be called jumping, but given that slugs are the quintessential slow-moving animals (slugs gave their name to the word sluggish), the vigorous twitching is certainly an un-slug-like behavior.

In contrast to slugs, snails keep their internal organs (guts) within the shell on their back and they have a strong, nimble, muscular foot. Slugs, which evolved from snails, have hollowed out their foot to accommodate their guts, since they no longer have a convenient shell for that purpose. Because the slug’s foot contains the guts, it is no longer as nimble as the foot of a snail.

The transition from snails (with external shells) to slugs (with internal or no shells) goes through an intermediate stage called a semi-slug, in which the animal has an external shell too small to accommodate the body. The guts are partly in the shell and partly in a hump on the semi-slug’s back. In the semi-slug form, the foot is still strong, nimble, and muscular. Many semi-slugs persist around the world today; in the United States, we have one species in the Smokey Mountains and several species in the Pacific Northwest.

Semi-slug with its body twisted as it thrashes its tail. — Figure 1. *Hemphillia* semi-slug thrashing its tail so the body flops about (photo: T.A. Pearce).

Semi-slug crawling across a piece of wood. — Figure 2. *Hemphillia* semi-slug crawling in typical slug-like motion (photo: T.A. Pearce).

The semi-slugs in the Pacific Northwest, in the genus Hemphillia, are commonly known as jumping slugs, although they are not commonly seen. The yellowish shell is visible through a slit in the mantle, and the internal organs are contained in a hump on the back. When I have found them, sometimes they will thrash the tail from side to side or twist it into a corkscrew shape and flop about like a fish out of water (Figure 1). In my experience, the Hemphillia slugs will “jump” for a second or two, then they crawl away at a normal slug’s pace (i.e., sluggishly) (Figure 2).

When I was in Madagascar (off the east coast of Africa), I saw a semi-slug of an unknown species on a leaf about a meter above the ground. When I reached to grab the semi-slug, it vigorously thrashed its tail, propelling itself off the leaf and safely into the vegetation below, not to be found.

A jumping snail (Ovachlamys fulgens) originally from southern Japan, arrived in North America in the past few years.The jumping snail sustains its vigorous jumping for a longer period of time than do the Hemphillia jumping slugs I saw in Washington State, and it covers more ground with its antics. See a video of the snail jumping here.

Why do they jump? First, let me say “why” questions are some of the hardest to answer in science. Science can never prove something to be true, we can only prove some things to be false (falsifying). To answer “why,” we try to think of all the possible answers, then set about testing each one, falsifying as many as we can. The remaining possibility (or possibilities) is our best guess at the truth, but we don’t know for sure because we are not guaranteed to have thought of all the possibilities.

The answer to why they jump has not yet been thoroughly studied, but people have speculated. The most common thought is that the slugs and snails likely jump to startle predators. A hungry predator that saw a tasty morsel flopping about might want it for lunch, but when the gastropod stops flopping, the predator might not be able to find it (and meanwhile the slug or snail surreptitiously crawls away). The jumping snails in the video jumped in response to prodding, and the semi-slug on a leaf evaded my grasp by jumping; both consistent with the idea that jumping could be an adaptation against predation.

Why don’t more snails jump? There are way more species of snails than semi-slugs, and although some semi-slugs jump, I am aware of only one snail that jumps. Jumping is therefore more common in semi-slugs than in snails. If jumping is an anti-predator adaptation, and given that the reduced shells of semi-slugs offer less protection from predators, I speculate that semi-slugs benefit from an additional anti-predator strategy.

Here is another mystery that I believe has not been studied: how can these gastropods jump If their mucus sticks them to the substrate? Snails and slugs are famous for their tenacious slime, by which they stick so firmly that they can crawl upside down on the undersides of objects. The answer might be that the jumping species have less slimy mucus, but I suspect that the answer involves variability in the mucus itself. Mucus changes its stickiness depending on how much pressure is applied. That is how snails can move (when they are stuck to the surface). My guess is that the jumping species can rapidly reduce the stickiness of their mucus when it is time to jump.

After the past year, when time sometimes seemed to crawl slowly by, it seems appropriate to write about leaping slugs and snails. And here is a bonus joke:

A jumping slug could jump higher than the Empire State Building.

That’s because the Empire State Building can’t jump.

Tim Pearce is the head of the mollusks section at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Can’t Touch This

by Andrea Kautz

From the name of them, you may guess “blister beetles” are insects you might not want to handle. However, they sure are beautiful to look at! We’ve been noticing blister beetles out and about at Powdermill over the last week or so. Some fly around clumsily, while other flightless species scurry among the leaf litter. Beetles in this family (Meloidae) secrete a defensive substance called cantharidin, a skin irritant that can cause blistering. They are also very toxic when consumed, and can be fatal for livestock if present in the hay supply.

Shiny blue blister beetle on a rock. — Two different genera of blister beetles that are common in SW Pennsylvania: *Lytta* (top) and *Meloe* (bottom). Top image credit: Shaun Pogacnik. Bottom image credit: Christian Grenier.

Blister beetles are parasites, mostly in the nests of ground-nesting bees and wasps. Watch this short video clip to learn more about their life cycle. Spoiler alert: In this species, the newly hatched beetle larvae clump together and attract a male bee using a fragrance, and then transfer to the female he mates with, ultimately gaining access to her nest, where they feed on both the pollen provisions and the bee larvae themselves!

Whether larvae or adults, these striking beetles certainly have a fascinating dark side. There is always more than meets the eye when it comes to entomology!

Andrea Kautz is a Research Entomologist at Carnegie Museum of Natural History’s Powdermill Nature Reserve. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Pittsburgh’s Moths Reflect Human Impact of Industry

by Nicholas Sauer

I began to think in earnest about industrial melanism while working at the Carnegie Museum of Natural History in 2018 when the We Are Nature exhibit was on display as part of the museum’s intensive focus on the Anthropocene. There was an unassuming corner of the exhibit devoted to the fate of the peppered moth (Biston betularia) during the Industrial Revolution. Dark-colored—melanistic—peppered moths were rare in England and Germany until the Industrial Revolution and the inevitable increase of air pollution from the burning of fossil fuels. With the rise of heavy industry, pale peppered moths began to stick out like bright specks on soot-covered vegetation. These pale moths were easy targets for hungry birds. The coal-choked environment favored the moth populations that possessed a gene for darker coloration, providing an example of natural selection at work. In recent years, scientists have located the specific gene that accounts for the darker moths and can trace the changing selection on color variation in peppered moths back to at least 1819 when the burning of coal for industrial purposes began to pick up steam in the British Isles.

In 1896, English entomologist J.W. Tutt theorized that his nation’s industrial conditions profoundly affected local moth populations. He argued that lichen on trees provided camouflage for the salt-and-pepper-colored moths. According to Tutt, industrial pollution killed off the lichen and, in turn, the pollution—soot and ash—camouflaged the darker moths, particularly the dark form of Biston betularia, f. carbonaria. It was not until the 1950s that Tutt’s theory was tested. Through a series of experiments, lepidopterist Bernard Kettlewell demonstrated that when both light and dark peppered moths (f. typica and carbonaria respectively) were released in industrially-contaminated woodlands in Birmingham and Dorset, England, birds fed on the most “conspicuous” form, f. typica, the pale moths. Kettlewell’s experiment would wind up in science textbooks for decades to come as a demonstration of natural selection.

Black moth on light background. — “[1931] Peppered Moth (Biston betularia) f.carbonaria” by Bennyboymothman is licensed under CC BY 2.0

In the wake of Kettlewell’s findings, similar experiments were conducted in the United States, even in the Pittsburgh area. The scientist leading the melanism study in the Eastern United States in the 1950s, Denis Frank Owen (1931-1996), pored over the moth collections right here at the Carnegie Museum of Natural History as well as those of several other natural history museums in the Northeast and Midwest. A transplant from England at the beginning of his long career as an ecologist, Owen sought to test whether or not Kettlewell’s results would be reflected in his own data on the American side of the Atlantic. Owen’s own findings were very much like Kettlewell’s. This, of course, was unsurprising in the case of Pittsburgh considering the massive amount of pollutants that were emitted by the city’s steel mills. To get a good idea of how polluted the city was at that time, check out the two soot-stained squares that remain on the mural The Crowning of Labor on the second and third floors of CMNH’s Grand Staircase.

Owen discovered that Pittsburgh had some of the earliest records of industrial melanism in the Northeast—melanistic forms of Epimecis hortaria (or, the Tulip Tree Beauty) dating from 1922 and Biston cognataria dating from 1910. Owen posited in his research that the number of melanistic moths were increasing in the late 1950s and early 1960s, particularly in environs surrounding industrial cities like Detroit and Pittsburgh, even as far as outlying rural areas. At Westmoreland County’s Powdermill Nature Reserve, all eight of the peppered moths observed in a 1957 study were melanistic, according to Owen.

Unfortunately, records of industrial melanism were never kept as meticulously in the U.S. as they were in the U.K., so our understanding of how widespread the phenomenon was States-side is incomplete. However, since the 1970s, much more data has been collected on peppered moths in the U.S. than before. This data has reflected the implementation of clean air regulations and tracked the overall decline in the ratio of melanistic peppered moths in favor of the pale form, supporting the theory that these moth populations, either Biston betularia (f. typica or carbonaria) or their cousins, are subject to natural selection that is weighted by pollution. Biologist Bruce S. Grant has suggested that more recent data from the post-industrial era be put to greater educational use—not to supplant Kettlewell’s famous experiment, but to supplement it with more up-to-date scientific findings.

Regrettably, even in the “Post-Industrial” era following the birth of the Environmental Protection Agency (1970) and the Clean Air Act (1972), peppered moths are subject to human-exacerbated environmental threats. In the 1980s, when scientists sought an explanation for the continued presence of melanistic moths in rural eastern Pennsylvania, they instead discovered two major dangers to peppered moths and their habitat. First, so-called gypsy moths (Lymantria dispar dispar)—an invasive species introduced to the U.S. by humans in the 19th century—were rapidly defoliating the woodlands that the peppered moths called home. Secondly, the Pennsylvania Department of Forestry was spraying the area with the pesticides Dylox and Dimilin to combat Lymantria dispar and may have adversely affected the peppered moths in the process.

This example of the twin dangers of invasive species and pesticide use, in addition to the earlier instances of industrial pollution, demonstrate human beings’ profound effect on the natural world during the Anthropocene. The travails of the peppered moth are key to understanding the influence humans have on the ecosystems around them, so far as becoming even a variable in the way natural selection operates. The Pittsburgh area and the scientific collections at CMNH have played an important part in the study of industrial melanism in peppered moths and will continue to do so as the natural world responds in its way to human influence. The decline in melanistic moth numbers that correlates with cleaner air and more conscientious environmental regulations provides hope that that human influence is not uniformly negative.

Nicholas Sauer is a Gallery Experience Presenter in CMNH’s Life Long Learning Department. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Works Cited

Blakemore, Erin. “New Evidence Shows Peppered Moths Changed Color in Sync with Industrial Revolution.” Smithsonian Magazine, 1 June 2016. <https://www.smithsonianmag.com/smart-news/new-evidence-peppered-moths-changed-color-sync-industrial-revolution-180959282/>.

Cook, M.L., et al. “Post Industrial Melanism in the Peppered Moth.” Science, no. 3 (Feb 7, 1986): 611. Gale In Context: College, link.gale.com/apps/doc/A4128493/CSIC?u=pitt92539&sid=CSIC&xid=56d31b9d. Accessed 17 Apr. 2021.

Grant, Bruce S. “Fine Tuning the Peppered Moth Paradigm.” Evolution 53, no. 3 (1999): 980-984.

Grant, B.S. and L.L. Wiseman. “Recent History of Melanism in American Peppered Moths.” Journal of Heredity 93, 2 (March 2002): 86-90. <https://academic.oup.com/jhered/article/93/2/86/2187377>.

Manley, Thomas R. “Temporal Trends in Frequency of Melanistic Morphs in Cryptic Moths of Rural Pennsylvania.” Journal of the Lepidopterists’ Society 42, no. 3 (1988): 213-217.

Maynard, M. and Geoffrey T. Hellman. “Comment.” The New Yorker Magazine, 13 August, 1955: 15. <https://www.newyorker.com/magazine/1955/08/13/comment-4365>.

Owen, D.F. “Industrial Melanism in North American Moths.” The American Naturalist 95, no. 883 (Jul.-Aug., 1961): 227-233. <https://www.jstor.org/stable/2458933?seq=1>. Accessed 18 April 2021.

Rudge, David Wyss. “The Role of Photographs and Films in Kettlewell’s Popularizations of the Phenomenon of Industrial Melanism.” Science and Education 12 (2003): 261-287.

Smith, David A.S. “Obituary: Denis Owen.” The Independent, 23 Oct. 1996. <https://www.independent.co.uk/news/obituaries/obituary-denis-owen-1359897.html>.

Incredible Junk Food Diets: Creatures That Clean Up Our World

by Shelby Wyzykowski with scientific information provided by Dr. Ainsley Seago, Associate Curator of Invertebrate Zoology.

What could be more thrilling than a summer weekend trip to explore one of the most exciting metropolises in the world, New York City. It has so much to offer, way too much to experience in a mere two or three days. There’s the sights…the Statue of Liberty, the Empire State Building, and Broadway. There’s the sounds…the beeping horns of taxi cabs and the noisy, bustling, crowded sidewalks. And there’s the smells…the sweet fragrances that drift from stalls in the Flower District, the tantalizing aromas wafting from street-side food carts, and the unmistakable odor of sixty thousand hot dogs sitting under the noon day sun in Times Square. Sixty thousand hot dogs? Really?! Well, no, not really, at least not literally. But the city that never sleeps is a city that loves to eat. And with the number of people that live, work, and visit this town, enormous amounts of food can litter the streets at any given time. The battle to keep public spaces free of food waste is daunting, but humans do have some unlikely tiny allies in this unending garbage war…insects. These crews of itsy-bitsy street cleaners, along with other arthropods like spiders and millipedes, are surprisingly efficient scavengers. We undoubtedly know this thanks to the work of researchers at North Carolina State University. Their entomologists, or insect scientists, studied these mini trash disposals at work in the urban ecosystem of New York. They found that pavement ants, cockroaches, and other hungry foragers can eat 2,100 pounds of food refuse (the equivalent of 60,000 hot dogs) in one year. Now in the grand scheme of things, a ton of food is not a lot, but researchers have still taken notice. They know that diverting food waste from landfills benefits our planet. And they are experimenting to try and find innovative ways to use insects to transform edible trash into eco-friendly treasure.

macro photo of an ant holding a bit of bread — Image by cp17 from Pixabay.

Entomologists at Louisiana State University are also doing their part to make their Baton Rouge campus more environmentally responsible. They’ve collaborated with the nearby Fluker Farms, a pet supply business that sells insects as reptile food. Together they’re taking food bound for a landfill and transforming it into animal feed. But there is also a third indispensable partner in this entomological endeavor. It’s the black soldier fly, an insect that is common in the Southern United States. The larvae of the black soldier fly do one thing exceptionally well…eat. A black soldier fly larva can eat twice its own body weight in one day! During their larval stage, they consume all the food that they’ll need for the rest of their lives. The fly’s feeding frenzy results in rapid growth. They’ll grow 300% in size during their two-week larval stage. But, after these two weeks, they’ll never eat again. It would be impossible, because an adult black soldier fly has no mouth!

Before the larvae can chow down on the leftovers from the campus’s dining halls, the food scraps have to be blended into a slurry. Then the ravenous little larvae get two weeks to eat to their heart’s content. They are then sifted out of the remaining slurry. Some larvae are sold as Fluker Farms reptile food while the others return to the colony to become adults. The leftover slurry/compost mixture is then spread on the flower beds that decorate the university’s campus. In 2019 alone, 15 tons of food waste was processed this way! The joint effort between LSU’s Entomology department and Fluker Farms is helping the university to reach its goal to reduce the amount of waste the campus sends to landfills by three quarters by the year 2030.

But the LSU scientists have an even grander vision for their larvae farm and other farms like it. Black soldier fly larvae can also take the place of soy and fish meal as feed for livestock, and this helps to take the pressure off the world fisheries. With an ever-increasing world population, perhaps larvae may even become a food staple for humans someday. Food scientists at Stellenbosch University in South Africa are already using black soldier fly larvae to produce dairy-free ice cream and Vienna-style sausage. Imagine, someday, sitting down to enjoy a full seven-course dinner with larvae as a key ingredient!

Fly larvae are not the only insects that are being utilized as animal feed. Cockroaches, which are actually very fastidious, well-groomed insects, are great little amateur recyclers. They can chew down almost anything, but they can live without food for up to one month if they need to. Luckily, the roaches at the Shadong Agricultural Technology Company in Jinan, China never need to worry about going hungry. The food waste recycling plant works on a much larger scale than LSU, housing a billion cockroaches that are fed fifty tons of kitchen scraps each day. That’s the equivalent of seven adult bull elephants! The cockroaches are allowed to live out their natural lifespan. Then they are steamed, cleaned, and processed into a protein-rich, antibiotic-free livestock feed that, like larvae, can take the place of fish meal. This profitable food waste plant, as well as others like it in other Chinese cities, undoubtedly proves that insect farms can help to solve our landfill problems.

Landfill with bulldozer. Evergreen trees and gray sky in the background. — Image by Pasi Mäenpää from Pixabay.

With the success of these promising initiatives, scientists are taking things a step further and applying insects to the problem of plastic waste. It’s no secret that the many types of plastic that we use in our everyday lives are polluting the planet. Marine ecologists have even found plastic microfibers in sea ice samples from Antarctica! Some researchers, in their quest to try and help to solve our plastic problem, have made a surprising discovery; some insects are plastivores, meaning they can eat plastic! A March 2020 project at Brandon University in Canada studied the larvae of the Greater Wax Moth (a regular beehive pest) and their ability to consume LDPE, or low-density polyethylene. This type of soft plastic, which is used to make grocery bags, is one of the leading contributors to non-biodegradable waste. It can be recycled, but much of it ends up in the trash. At the landfill, LDPE breaks down and releases dangerous greenhouse gases, including methane. This is cause for concern, since greenhouse gases contribute to climate change. Brandon University researchers have been trying to figure out the exact way that these caterpillar larvae are able to digest this troublesome plastic. Their goal was to isolate and identify the specific chemical that the caterpillar uses to break down LDPE, and they got off to a promising start. The scientists found that the amount of the larvae’s gut microbes (bacteria and fungi) actually increased when fed LDPE. Their intestinal biome actually preferred it over the caterpillar’s regular natural diet of honeycomb. The larvae thrived on plastic! And they seemed to love it because LDPE has the same chemical structure (specifically, a long, open-chain hydrocarbon) as beeswax! Further research revealed that the caterpillar’s breakdown of LDPE is a complicated process that has to happen in vivo (inside their bodies). One of the waste products that the caterpillars produce when they digest LDPE is called glycol. Glycol is toxic to humans, but, fortuitously, it can be biodegraded by several common, naturally occurring bacteria. For now, recycling LDPE is still the best option. But further research into the Greater Wax Moth larva’s in vivo process of digesting plastic may prove to be fruitful.

This summer, even if you’re not able to escape for a weekend getaway to the Big Apple, you are still likely to get the opportunity to enjoy a Sunday stroll along the sidewalks of your own hometown. And if, by chance, you look down and see a line of ants diligently portioning out and carrying away a cast-off crust of bread, take a moment to stop and watch them hard at work. You can maybe even silently thank them for their Herculean efforts. If it weren’t for their help, food waste would be an environmental hazard, a threat to public health, and an additional financial burden to your city. It’s a dirty job, but somebody’s got to do it. Fortunately for us, our voracious, multi-legged little friends are ready and willing to take on the task.

Shelby Wyzykowski is a Gallery Experience Presenter in CMNH’s Life Long Learning Department. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Reading Results: CNC Final Phase

by Patrick McShea

Whether you participated in the recent City Nature Challenge (CNC) or not, the results of the Pittsburgh Region’s broadest annual citizen science biological survey might be of interest.

The visually rich and geographically referenced compilation is a record of 1,219 different species of free-living plants, animals, and fungi documented, via the iNaturalist phone app, by 446 observers within six southwestern Pennsylvania counties during four mid-spring days. It’s a site where anyone with an interest in local natural history can spend a lot of time exploring.

Participation in Pittsburgh’s 2021 CNC was 16% lower than during the 2020 event, a reduction resulting in a similar-sized decline in total observations, yet only a 10% drop in the total number of different organisms documented. This year’s event was held April 30 – May 3, nearly a full week later in the spring than the 2020 CNC, a modification that might have increased the likelihood for some organisms to be observed.

A flowering garlic mustard plant growing at the base of a black walnut tree.

Garlic mustard (Alliaria petiolata), a highly invasive plant introduced to North America in the mid-1800s for its herbal value and erosion control properties, was the most commonly documented organism, accounting for 98 of the Pittsburgh Region’s 7,045 total observations. On the results page, where visitors can further explore every documented species, there’s information to be gleaned beyond the common and scientific names of each entry. Far down the rankings, for example, all four images of organ-pipe mud-dauber nest chambers show the wasp-build tubes attached to human-built walls, and both seal salamander images appear to be illuminated by flashlight or headlamp.

Tubular nests built by the organ pipe mud dauber, a wasp species that preys upon spiders.

As a category, plants, and frequently their blossoms, account for over half the total species documented. Birds, which included some migrants passing through the Pittsburgh region, led the vertebrate class with 111 species documented. Mammals followed with 21 documented species, and documented species for amphibians and reptiles numbered 16 and 13, respectively. 197 species of insects were documented, as were 137 species of fungi.

Participation levels are also carefully recorded in the results, with CMNH’s own Mason Heberling, Assistant Curator of Botany, leading the pack with 403 recorded observations of 208 different species. He explains his level of activity as a response to the scientifically sound parameters established by the CNC organizers. “Because it is roughly the same time each year, I have made a habit of going back to the same several sites each year, mostly ones that are convenient and nearby to me, and ironically, ones I don’t often get to as much as I wish I could. I do that with hopes of after going back to the same handful of sites around the same time, year after year, we can look at year-to-year and longer-term differences.”

And CMNH’s own Bonnie Isaac, Collection Manager in Botany, was among 397 identifiers who contributed time and background knowledge during a critical six-day second phase of the CNC to review and identify the observations of other participants. In fact, Bonnie identified 872 observations during the challenge. Within the operations of the iNaturalist app, observations with GPS coordinates that are identified by two separate reviewers are termed “Research Grade,” meaning they can contribute to the data sets of future studies. Nearly 54% of the Pittsburgh Region’s CNC observations earned the research grade mark this year, a very slight increase over last year’s mark.

Through the CNC and other citizen science survey projects, the contributions of observers and identifiers enables the powerful image recognition software of the iNaturalist platform to increasingly transform our phones into broad spectrum field guides. As you scroll and click through this year’s CNC results it’s also worth reflecting upon what is both gained and lost through a digital interface.

In a 2015 New York Times essay titled Identification Please, naturalist Helen Macdonald pays homage to the low-tech field guide by first calling out their flaws:

Out in the field, birds and insects are often seen briefly, at a distance, in low light or half-obscured by foliage; they do not resemble the tabular arrangements of paintings in guides, where similar species are brought together on a plain background on the same page, all facing one way and bathed in bright, shadowless light so they may be easily compared.

She later explains the great value of field guides in preparing our eyes and minds for what we hope to observe:

Field guides made possible the joy of encountering a thing I already knew but had never seen before.

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Collected on this Day in 1982: One specimen isn’t always enough!

Archiving biological variation.

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Leaping Slugs! Did that Slug Just Jump?

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Can’t Touch This

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