Circus of the Spineless #52

Welcome to the 52nd edition of Circus of the Spineless!

Hey you in the back - yeah, you - the one with the spine - get outta here! This circus is only for the spineless!

Since it's only us invertebrate lovers here, I know I can be honest with you - one of the reasons I think the spineless are so cool is that they can sometimes be very gross. You know what I mean - laying their eggs inside of other animals, eating them alive, etc., etc. So I thought that a nifty way to arrange this month's posts would be in order of grossness.

Since beauty (and grossness) are in the eye of the beholder, you may not agree with my arrangement. You may even be offended. That's OK, I don't mind, I have thick skin (actually sort of an exoskeleton).

Why don't we start at the beautiful end of the scale and work our way to the beastly end:

Zen Faulkes at NeuroDojo writes about the correlation between coloration and toxicity of sea slugs. In a post about coloration, how could you not have some really beautiful photos? Zen does not disappoint!

As glorious as the photos in Zen's post are the words in the poem submitted by Elaine Medline. Elaine writes about seeing the world through a dragonfly's eyes in her blog Memorizing Nature.

Many creatures inhabit the middle world between beauty and beast. Amber Coakley at Birder's Lounge writes about the sawfly, which starts its life as a somewhat attractive larvae and ends up a scary looking adult.

Or how about an insect that is graceful when observed from afar, but gets a little ugly if you get too close? JSK at Anybody Seen My Focus demonstrates this in a series of photos of a Great Blue Skimmer dragonfly, with very bugged-out eyes.

Marine invertebrates can be that way as well, beautiful from a distance but like slimy phlegm up close. Check out the sponges and other creatures discovered by Susannah's grand-daughter at Wanderin' Weeta.

Over at Wild About Ants, the "Consult-Ant" Roberta Gibson answers a question about ant pheromones. Ants are fascinating social insects and generally not too gross. A very interesting post!

Back to Zen Faulkes at NeuroDojo, this time for a review of a field study of a cricket population. This was an amazingly comprehensive study by some very patient researchers. They even tagged the crickets, which makes for a pretty funny photo.

We are now about halfway through our spectrum of grossness, so we are starting to tilt to the gross end. The Dragonfly Woman at her eponymous blog writes about aquatic insects being used as biological indicators of water quality. The Santa Cruz River in Tucson is 100% effluent (wastewater) and is filled with bloodworms. Need I say more?

Next we visit the blog of yours truly, John at Kind of Curious, where we find a moth that disguises itself as a bird dropping. Or, as one of the commenters noted, a shelf fungus.

Adrian Thysse, also known as The Bug Whisperer, provides a series of fascinating photos of an Ichneumon Wasp finding a larvae inside a log by echolocation, and then depositing its egg in the larvae. Now this is the kind of truly gross stuff I am talking about!

It is no coincidence that the revolting end of this spectrum of grossness is heavily populated by arachnids. David Winter writes about conservation of the Katipo Spider at The Atavism. Maybe it's just me, but I think most people would run from this spider.

Ted MacRae at Beetles in the Bush addresses the beauty/beast issue head on - he argues that jumping spiders are actually cute and cuddly! I'm not buying it, but he does provide some excellent close-up photos.

As we near the end of the grossness scale, our more fair readers may wish to avert their eyes. Michael Bok at Arthropoda provides an in-depth discussion (with photos!) of Camel Spiders, which are actually not true spiders but their own order within the arachnids.

What could be more gross than a spider? How about a wasp dragging a spider back to her nest to lay her eggs it its body? David Winter provides some great shots of this at The Atavism.

Finally, the post I have nominated as the most revolting, nauseating and disturbing of the bunch. Unfortunately, this one demonstrates the greed of humans, the short-sighted disregard of multiple procedures intended to protect other humans and our life-giving ecosystem. I am referring to the BP oil spill. Kevin Zelnio, administrator of Circus of the Spineless, submitted a post by Dr. Chris Mah on the Ocean Portal Blog of the Smithsonian Museum of Natural History. Dr. Mah's post describes the impact of the BP oil spill on invertebrates in the Gulf, which may be an even greater disaster than the impact on the more photogenic vertebrates we see on television.

Well, that's a wrap for Circus of the Spineless #52. I hope nobody was offended if I called your favorite invertebrate "gross". It was all in fun.

Next month, the spineless will converge at Birder's Lounge (I hope no one gets eaten!). Send your submissions to acoakley at birderslounge dot com.

Daddy Long Legs Daddies (aka Harvestman)

More from Life in the Undergrowth Episode 1 - Sir Attenborough stuck his micro camera in a "harvestman" nest, and showed a male guarding a nest filled with about 25 eggs. This creature, which looked like a spider, was constantly cleaning off the eggs. Occasionally a female harvestman would stop by to mate, and she would add her eggs to his collection. This egg-sitting service was provided to more than one female. At one point, a female tried to eat one of the eggs. After the male chased her off, he scurried around and seemed to be counting the eggs to make sure they were all there. He didn't stop until he seemed satisfied that his brood was safe.

Trying to find out more about this harvestman wasn't so easy. Sir Attenborough didn't mention the particular species he was observing, and it turns out there are thousands of them. But searching around the web (no pun intended, since harvestmen don't make webs), I discovered that what he showed was most likely a Zygopachylus albomarginis.

I was surprised to find out from my research that the "American" name for a harvestman is "daddy long legs". In the UK, they use the term "daddy long legs" to refer to a crane fly. The harvestman they showed in the video did not look or act like the ones I commonly see in New Jersey. Apparently Z. albomarginis lives in Panama. The Jersey harvestmen look more like the one in the photo above, but with a more rounded and darker body.

The most surprising thing I discovered is that despite their appearance, harvestmen are not spiders! They are arachnids, so they are related to spiders, but there are some differences. Spiders have a narrow waist (pedicel) between their two body sections, breathe using book lungs (more on that here), and produce silk. They eat by piercing their prey with fangs, injecting venom and digestive juices, and sucking out the digested contents. Harvestmen have an oval body (no waist), breathe by diffusing air directly from their tracheae into their "blood" (no lungs), and do not produce silk. They also do not produce venom, so they eat by ripping their prey into small pieces and transferring these to their mouth.

I'll leave you with a fun assignment for the next time you are in the woods at night (although it may be too cold to do this now in the northern latitudes). Take a flashlight and hold the butt end against your forehead, just above your eyebrows. Point the beam of the flashlight straight out, parallel to your line of vision. Then look around until you find a set of glowing green eyes looking back at you. Walk toward the eyes, keeping the flashlight on them, and you will find a spider. No kidding!

Thanks to Wikimedia Commons for the photo.

Arachnid Lungs Evolved From Horseshoe Crabs

I have been watching videos of the BBC television series Life in the Undergrowth with David Attenborough. It starts off by explaining how life got in the undergrowth to begin with, in other words, how it crawled out of the sea. One example he discusses is the horseshoe crab.

The horseshoe crab is actually not even a crab, it is an arthropod of the subphylum chelicerata, which means it is more closely related to the arachnids like spiders, scorpions and ticks than it is to crabs. Sir Attenborough showed thousands of horseshoe crabs crawling out of the water for their annual spawning. Living in prime horseshoe crab territory in New Jersey, I have seen many of these ancient creatures gracing our beaches.

Attenborough explained that since horseshoe crabs were among the first animals to develop the ability to venture onto land, they had a distinct advantage in that they could keep their eggs away from their enemies who were still in the water. They no longer have this advantage, since many birds look forward to the annual horseshoe crab spawn every year. This is especially true of the red knot, which feasts on the horseshoe crab eggs during its migration stop-over in the Delaware Bay. This species of sandpiper makes an amazing annual migration from one end of the Americas to the other, from the Canadian Arctic to Tierra del Fuego at the southern tip of South America!

The adaptation that allowed the horseshoe crab to venture onto land was the "book gill", which you can see in the top photo just above his tail. Each of the folds that is visible in the photo has many more folds within it, with the overall structure looking like the pages of a book. This gill is on the outside of the horseshoe crab's body, so as long as he keeps it moist with the small amount of water in the wet sand, he can live out of the water up to a week. The many folds increase the surface area for gas exchange to his blood.

Fast forward to modern-day spiders, close relatives of the horseshoe crab. Below is a cross-section diagram, with #16 being the "book lung". This is essentially the book gill of the horseshoe crab, evolved to be located within the spider's body, and supplied with air through a small opening. Scorpions have a similar setup. Pretty amazing that these small land animals have lungs evolved from an ancient sea creature. Thanks to Wikimedia Commons for the photo and diagram.