Arachtober

Having failed to get out in the garden early, while it was sunny and there might have been some easy invertebrate pickings to be had, I was faced with trying to find and photograph reluctant subjects this afternoon, in very poor light. In the end I resorted to beating a few things out of their roosts, and used flash. I was fairly happy with the twin flash and diffusers I bought last winter, but I found that I was still having some trouble with specular highlights on the shinier bugs, and over the summer I've been pondering what I might do to reduce them. Today's experiment was to put a small scrunch of medical gauze inside each diffuser, which helped to an extent, though I think I'd need to use quite a bit more to really flatten the light.

Luckily none of the three spiders I'm posting tonight was especially shiny, though the background leaf in the main image is brighter than I'd have liked. The subject here is a Green Crab Spider, Diaea dorsata, which I beat from the Lawson cypress, where it will have been perfectly camouflaged as it lurked in wait for prey. I'm getting very mixed messages from this individual, which has the typical dark leg and prosoma markings of a male, but otherwise looks more like a female. If it is a male it must be sub-adult, because on their final moult into adulthood male Green Crab Spiders develop outrageously long legs, and also tend to turn much yellower than this. It would be unusual to find an adult male this late in the year because they don't live long after mating, but females can persist into the autumn, and sub-adults overwinter in bark crevices. Adult males are around 3-4mm long (excluding the exhibitionist legs), and adult females are around 5mm; this specimen was towards the upper end of that range.

My second photo shows a male Green Mesh Web Spider, Nigma walckenaeri, which arrived on the beating tray along with the Green Crab Spider, but was noticeably smaller in every dimension, and much more passive. Adult males of this species are around 3-4mm long, which is the same length as an adult male Green Crab Spider, but they're narrower and have shorter legs, and they appear generally less robust. This individual might just about have stretched to 3mm.

The third photo shows an adult female Green Mesh Web Spider, which was about 5mm long, and more heavily built than the male. Luckily I spotted her in her retreat on the smoke bush as I was walking past, so I was able to photograph her in situ without disturbing her. Both male and female Nigma walckenaeri persist well into the autumn, and females have even been recorded in the middle of winter.

R: C6, D7.