Oh, Just a Harvestman Eating a Velvet Worm Under UV Light... - Observation of the Week, 5/10/22

Our Observation of the Week is this amazing scene: a Cranaid Harvestman (Family Cranaidae) eating an Equatorial Velvet Worm (Genus Oroperipatus) in Ecuador! Seen by @m_ellis.

Mike Ellis is a PhD candidate at Tulane University, and he credits his parents for helping him get outside and explore nature at a young age, even though his interests tended toward books and playing Pokémon. He did bring that “gotta catch ‘em all” mindset to his later study of biology and ecology, and tells me

as a freshman at Hobart & William Smith Colleges, the first course I enrolled in was a seminar called “Bird Obsessions,” and my advisor, Dr. Mark Deutschlander, issued our class a challenge to see who could find the most bird species in a single semester. That competition planted the seeds for my own bird obsession, and two years later, a semester abroad in Ecuador and Peru officially converted me into a conservationist and birder hooked on “seeing them all.”

For the last six or seven years, Mike has been “immersed in tropical ecology, ornithology, and conservation [in Ecuador] with two nonprofits dedicated to protecting and restoring the country's critically threatened western forests: Third Millennium Alliance (TMA) and Fundación para la Conservación de los Andes Tropicales (FCAT),” and that’s where he stumbled up on the really cool predation event documented here.

With forests in the area disappearing quickly, Mike says one often runs into other scientists “doing amazing work,” and on the night of this observation he was helping TMA’s herpetologists Moisés Tenorio and Diego Quirola look for Bothrops asper snakes. “I was out searching for anything that might look funky under a UV light and hoping to catch a glimpse of whatever their expert herper eyes could find that my birder eyes might miss,” he tells me, 

[and] I had just finished marveling at a glowing frog and was slogging through some cloud forest mud to catch up with the others when my UV light landed on something electric blue sticking out against the blood red spikemosses covering the forest floor. Harvestmen are a dime a dozen here, but they tend towards yellow or green under UV light and often aren't this vibrantly luminescent, so I leaned in for a closer look. I was jazzed by what I saw, more so because it was my first ever onychophoran (velvet worm) than because of the predation I was witnessing! At Tulane, I teach intro ecology and evolutionary biology labs on the diversity of life, and we have a week dedicated entirely to ecdysozoans (critters that grow by molting their exoskeletons). Onychophorans have always been, in my opinion, one of the more fascinating members of that group, made all the more intriguing by the fact that it's one of the few taxa I teach about that I'd never before encountered in person. 

Mike’s right, velvet worms are pretty remarkable creatures. Averaging about 5 cm (2 inches) in length, they use their stubby feet to crawl on the ground, searching for prey. When a velvet worm assesses that an organism might be a good meal, it immobilizes the prey by squirting glue-like slime over it! 

Harvestmen, often called daddy longlegs, often do have very spindly legs and lack both venom and silk glands. Some scavenge and others hunt, and what’s really cool is that they are able to eat solid food, whereas most other arachnids can only ingest liquids. They comprise their own order within the arachnids and are not spiders. 

Working with Dr. Jordan Karubian from Tulane, Mike (above) is doing research that 

leverages remote sensing and field data to determine how anthropogenic forces pair with natural environmental gradients to reshape forest structure and avian communities in the region. My ultimate goals are to improve our understanding of tropical landscape and climate change impacts and to generate tools and data that will help us better monitor, prevent, and reverse declines in diversity and ecosystem function.

An iNat user for about four years now, Mike says he likes the connections it builds between naturalists of all stripes, especially important for conservation work as experts can provide identification help with endangered and potentially undescribed species. And,  

lastly, I love and use iNaturalist because it's a great way to foster a culture of gratitude and reciprocity, both with nature and with each other. Often, learning an organism's name is the first step people take towards really knowing and caring for that organism, so the ability to make and share identifications on this platform is very powerful. It's a place where we can share the gift and responsibility of knowledge, so I always try to give back a bit more than I receive by keeping my community ID numbers ahead of my own observation numbers. I encourage you to try doing the same! Even if you feel you're just a seedling of a naturalist in a forest of experts, there's always a niche for you here to grow into and share.

- Check out this video about a physicist studying the velvet worm slime squirting.

- An early Observation of the Week by @steve_kerr documented a harvestman with a “Phineas Gage” injury. 

- Just take a look at the most faved velvet worms and harvestmen on iNat - amazing!

- iNatter @leftcoastnaturalist debunks the myth that “daddy longlegs” are the most venomous creatures on Earth. 

Posted on May 10, 2022 09:30 PM by tiwane