Tony Eales, a Research Officer from Queensland, writes in with some lovely arthropod photos. His notes are indented.
So it’s winter in the southern hemisphere, and insects and other arthropods are more difficult to find. However when that happens I turn to the leaf litter. I collect a bag of litter from a likely looking spot and then sort through handful by handful on a white bucket lid, looking for movement. The bucket lid helps me see the tiny things crawling around but also has another effect. With a little manipulation of black/white levels on photoshop and some erasing I can isolate the subject in the photo against a white background. This effect can really help bring out the details of these tiny ground-dwelling creatures. Here’s a sample of some of the things that I’ve pulled out of the litter.
Having said all that the first subject is one from the trees rather than the ground. It’s a small male orb-weaving spider Araneus arenaceus the Sandy Orb-weaver. When disturbed, it heads to a twig and hunches up into this shape and becomes basically invisible, looking like any other small protrusion.
Commonly in the rainforest leaf litter I find harvestmen, arachnids in the Order Opiliones. The commonest are these peculiar creatures in the genus Bogania. I can’t find much information about them but I find the huge articulated spiked jaws fascinating. I’d love to observe them catching prey.
The thing about looking at the small stuff is that you’re going to be finding the unstudied stuff fairly regularly. This photo is of a spider in the cobweb spider family Theridiidae. Consulting with the experts on the spiders of my state, we can get it down to the subfamily Hadrotarsinae, but that’s as far as anyone can get. Despite many surveys of the leaf litter in my part of the world, some groups are just not known. I love the long setae on the back.
This is a tiny ant from a genus restricted to the Indo-Australian region. There are only nine described species and they live in small colonies of around 100 ants, foraging in the leaf litter. I think I’ve keyed this one out to Mayriella abstinens, but it’s definitely Mayriella sp. as identified by the deep antennal scrobes (grooves) in the head.
The rainforest leaf litter contains many tiny land snails, most often in the Family Charopidae. There are numerous species with very similar form and thus it is difficult to even get to genus with most that I find. This one, Nautiliropa omicron, however, is quite distinctive with a bi-concave nautiloid shell, delicate ridges and zig-zag patterning.
I’m not sure why this tortoise leaf-beetle was in the leaf litter, as I normally find them in the bushes on live leaves. It’s definitely in the genus Paropsisterna related to P. decolorata, but there’s a problem for researchers describing these beetles, as they have distinctive colours and golden iridescences until they’re dead, and then they lose their colour. It makes it very difficult to compare with the holotypes, many of which were sent to Europe and researchers here aren’t sure if a particular beetle already has a name or not.
Last, some more from my favourite order, spiders. This hairy one is a crab spider. An undescribed member of genus Sidymella. They appear to be fairly common in the leaf litter which is quite unusual for crab spiders. I can’t think of another one that lives on the ground.
Next, I am told by someone more capable in spider ID than I, is genus Spermophora…maybe. It’s a cute little jack-o-lantern-faced cellar spider, Family Pholcidae. I was trying to get to the bottom of what species it is and the key paper on Australian Pholcids has this to say “Spermophora is probably the most chaotic genus within pholcids”, plus it lists only two species in that genus—both far in the tropical north. So who knows. Cute, though.
Last is a jumping spider in the small genus Tara. It’s one of two types I always find in the rainforest leaf litter. Not very colourful for a jumping spider but with those big forward facing eyes they are the most appealing of all spiders.