Photojournal - 22 August 2007

Dusk discoveries

On Wednesday the 22nd, I went out around dusk to see what kind of insects and other little creatures I could find. Dusk is a good time to go looking, as the crepuscular and some nocturnal animals will be out.

First, in the planters on the way to the boardwalk, I found a pair of millipedes. (Recall that millipedes have two sets of legs per body segment, whereas centipedes have only one.) These particular millipedes are called the Greenhouse Millipede or Flat-backed Millipede, Oxidus gracilis. It's an invasive species, originally from the tropics, and it now infests most of the northern hemisphere if not the world.


In the right conditions, these millipedes can reproduce with abandon. Once, in Japan, an overgrowth of them coated a rail line densely enough to halt rail service for several hours while they were exterminated and brushed away. I'm not really sure if my specimens were mating or simply crossing over one another, but given their predilections, I'd guess the former.

Next I went down to check out the laurel bushes by the promenade. My first find was a little orange flier.


This lady is a braconid wasp. Braconids don't sting—that long "tail" is her ovipositor, not a stinger. Ovipositiors, naturally, are used to deposit ova (eggs). In the case of braconids, the eggs are deposited inside an insect or other arthropod, often a larva. Braconids are thus one of many parasitic families of wasps. This was a great find; I'd never seen a braconid before, although I had seen some of their closest cousins, the ichneumons.

Next I came upon a male mosquito, hanging on the bottom of a leaf, rear legs "raised", listening for the ladies.

The laurels are interspersed with rose bushes, and on one of the roses I found a Lucilla fly, more commonly known as a blow-fly or bottle-fly.  
Two flowers over, a fly with a grey abdomen made some comment about paparazzi and then mooned me.  

Sometimes I don't get no respect.

Anyhow, I figured I'd leave well enough alone, and moved on to the next laurel bush. There I found this delicate and long-legged fly. I haven't been able to identify this fellow any further.

On the other hand, my next subject was much easier. This beautiful copper-eyed creature is a Green Lacewing, a neuropteran in the family Chrysopidae. The details of the veins on the wings put this fellow in the genus Chrysopa or Chrysoperla, with Chrysoperla ploribunda (the Common Green Lacewing) being the most likely species.  

I like Green Lacewings not only for their elegant form, but also for one of their endearing habits: they play musical instruments in order to woo their lovers. Lacewings (of either gender) will find appropriate leaves or other plant matter and rhythmically twitch their bodies so as to vibrate the matter and thus create sounds. The pattern of sounds—the song—is distinctive to the species, much like birdsong. And presumably, if they play really well, they'll attract a mate. So it isn't a surprise to find that, by natural selection, these beauties have become virtuoso leaf-rustlers.

And no, that isn't at all like being a virtuoso cattle-rustler.

The next subject I found was a big ol' juicy earwig. This was pretty neat, as I don't recall ever finding an earwig in the neighborhood before. This particular earwig is a female European Earwig, Forficula auricularia.


European Earwigs are, curiously enough, native to Europe, and the best guess is that they've only been in North America for about a century.

My last subject of the evening was a spider I found near the security door that leads from the promenade to our courtyard. We get lots of spiders around our building, but this one stood out because he was either prepping or eating some new prey.


The long wrapped-up part of the prey (extending below the ball) is a wing, and I can't confidently say where the orange coloration on the main part of the prey comes from—it could very well be caused by the spider's digestive juices, which get injected into the prey once it's wrapped up. I don't know of any local insects with that color.

The other neat thing about this subject is that the spider is one that I haven't seen around here before: it's an orb weaver called the Grey Cross Spider, Larinioides sclopetarius. The vast majority of the orb weavers that we have around the building are the Garden Spider, Araneus diadematus. A. diadematus is also known as the Cross Spider, but that's not to be confused with the Grey Cross Spider.

It had been a short trip outside (about a half of an hour) but I had found an incredible diversity of little critters. I'll often spend whole days outside without finding this many new and interesting subjects.

Shaking a dried leaf,


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