Readers’ wildlife photos

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.

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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:

Finally, I found a video that Brigette made and sent me in 2014:
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:



  1. philfinn7
    Posted June 26, 2016 at 8:02 am | Permalink

    Wow1! All fascinating, but the parasite emerging from the dead caterpillar is incredible.

  2. Mark Sturtevant
    Posted June 26, 2016 at 8:15 am | Permalink

    These are lovely! I did not know that horseshoe crabs could fluoresce. The purple glow from the barnacles suggests that they do not fluoresce, as in giving off their own light, but are instead reflective of UV light.

  3. Mark Sturtevant
    Posted June 26, 2016 at 8:53 am | Permalink

    You certainly have an interesting menagerie of critters, Brigette. I also like the names you have given them.

    • Posted June 27, 2016 at 8:31 am | Permalink

      Thanks! I keep telling myself that I’m preparing myself to have my own human offspring – but for now, it’s me (and the fiance) and the animals 🙂

  4. Diana MacPherson
    Posted June 26, 2016 at 10:05 am | Permalink

    I love horseshoe crabs because they remind me of trilobites and Spock (different coloured blood).

    Brigitte, you must make a trilobite stuffed animal!!:)

  5. Posted June 26, 2016 at 12:01 pm | Permalink

    Wonderful photos! I want a plush tardigrade, too!

    • Posted June 27, 2016 at 8:36 am | Permalink

      I’ll keep you all in mind if I ever get back to sewing with the fuzzy fleece fabric again. Need to get my dissertation done first.

  6. Posted June 26, 2016 at 12:02 pm | Permalink

    Lovely tardigrade, Brigitte! Your work looks so interesting.

  7. rickflick
    Posted June 26, 2016 at 12:03 pm | Permalink

    Great views! The parasitoid reminds me of watching 17 yr cicadas emerge from the underground form – not to mention a certain sci-fi flick from a few years back.

  8. Mark Sturtevant
    Posted June 26, 2016 at 1:22 pm | Permalink

    Since the horseshoe crabs fluoresce very brightly in their leg joint membranes, I wonder if it is their famous blood that is doing the fluorescing.

  9. Leslie
    Posted June 26, 2016 at 3:31 pm | Permalink

    I grew up with horseshoe crabs (Long Island, NY) and have a 47 year old scar on the bottom of my foot to remind me (you really must watch your step around them). I never saw them fluoresce. The young ones are transparent, though.

  10. Posted June 26, 2016 at 5:26 pm | Permalink

    Awesome stuff!

  11. Chukar
    Posted June 26, 2016 at 7:09 pm | Permalink

    My vote goes with Diana MacPherson, #4 above. I have a strong affection for horseshoe crabs. When I was young and insensitive to the plight of others, I was unkind (I’ll leave it at that) to them. They looked so primitive and undeserving of my concern! Another guilt I’ll carry to my grave.

    They are greatly affected by storm surges, which wash them up on east coast beaches and embed them in banks and piles of sand and seaweed. When on their backs, it’s very difficult for them to extricate themselves. I found such a situation in So. Carolina and pulled hundreds of the still living out of the mess and carried them – by their tails of course, which was still fun to do – back to the sea where they’d slowly move off like little tanks. Even more of them had already died.

    In Delaware Bay, their millions (billions?) of eggs refuel Red Knots on their migration northward to the Arctic, another reason to be concerned for their continued survival, which is in peril.

  12. Posted June 27, 2016 at 8:42 am | Permalink

    Thanks for all the kind words!

    My friends are already planning on bringing much bigger/brighter UV lights next year, to try to get better photos. It was hard for our phone cameras to truly capture the bright fluorescence of some individuals – they shone like green beacons in the shallow water.

    Also – I should credit Piotr Naskrecki for the idea. I had remembered his blog, where he mentioned the fluorescent quality of horseshoe crabs. Hence, I grabbed my UV flashlight before I ran out the door for the beach.

    He’s got some great photos here, which look more accurate in terms of the colors we were seeing:

  13. Alex
    Posted June 28, 2016 at 11:15 am | Permalink

    Interesting stuff. I know this is probably silly, but I do have a small case of mottephobia. Not that I freak out when there’s a moth fluttering in the porch, but usually it’s the large moths with the eyespots that creep the f@@@ out of me especially if one picture of one pops up in a book I’m reading.

    • rickflick
      Posted June 28, 2016 at 3:02 pm | Permalink

      My spouse used to scream and cover her ears whenever a moth would get into the house. Over the years she’s gotten much better. I assume it comes from childhood when someone teased her about moths wanting to make a home in human ears.

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