Brigette Zacharczenko is a graduate student in the Department of Ecology and Evolution at the University of Connecticut, Storrs, working on the evolution of moths. Her other interests include biological illustration, keeping a menagerie of pets that few people would want around, powerlifting, making lovely plush animals (I want a tardigrade!), and coordinating events during National Moth Week. Beside the horseshoe crabs that are today’s main subject, I also found a video she sent me in 2014, which I don’t think I’ve posted.
First, the crabs, sent June 22 along with Brigette’s commentary. Note: horseshoe crabs—the ones below are the famous blue-blooded Limulus polyphemus—aren’t really crabs. While both groups are arthropods, horseshoe crabs are in the subphylum Chelicerata along with scorpions and spiders. “Real” crabs, on the other hand, are in the subphylum Crustacea. That means, of course, that the animals you see below are more closely related to spiders than to the crabs we eat.
Hello! I’m a long time reader and I thought you might enjoy these photos I took last night. My friends and I went to Napatree Point in Rhode Island hoping to see some mating horseshoe crabs (they typically mate during the full moon). It wasn’t the piles of chelicerates on the sand like you see in some photos, but we did see hundreds in the water by the shore! I remembered seeing some pictures of them glowing under UV lighting, so I brought a little handheld UV flashlight. As far as I can tell, no one is quite sure why they glow – or perhaps there is no reason at all, and it is a byproduct of how their exoskeletons are constructed? We did notice a lot of individual variation in the extent of their fluorescence, typically the fresher looking ones (recently molted, not covered in barnacles and limpets) would pop bright green.
We also got to follow the volunteers of “Project Limulus” as they were counting individuals, measuring body widths, and recording tags. Overall, it was a magical night.
These are from my phone, so I apologize for their size/dimensions.
Just to show you how big these mating aggregations can be, here’s a photo of individuals on Long Island Sound, courtesy of WNPR and the U.S. Fish and Wildlife Service:
If you want to learn more about horseshoe crabs, here’s a 50-minute documentary from WildOcean:
A student brought a caterpillar (Euchaetes egle) into my office, wondering if the caterpillar was still alive. It certainly was moving, but not for usual reasons.
The resident parasitoid had eaten the caterpillar, became restless, and decided to take a hike, perhaps to pupate. It is a fly maggot in the family Tachinidae. They commonly target caterpillars.
I took the video with my phone, at first only hoping to record the wiggling motions of the caterpillar. I was quite surprised when the parasitoid fully emerged!
That reminded me of the botfly that emerged from my head.
Sadly, these are no longer available: