A mature St Andrew’s Cross spider (Argiope keyserlingi) has set up her web between two maidenhair ferns on our back patio and I noticed yesterday morning that she had caught and wrapped a substantial meal, perhaps a fly or a small moth.
Looking more closely after lunch (my lunch, that is, not hers), I saw a much smaller spider hanging around in the edge of her web.
The macro lens with a close-up filter was able to show that it was a Dewdrop Spider, Argyrodes antipodianus, and even that it was a male (those “boxing gloves”, really enlarged palps, are the giveaway). St Andrews Cross females grow to 16 mm according to Arachne.org while Dewdrop males grow to 2.5 mm according to the same site, and both were close to those sizes.
Dewdrops and others in the same genus are kleptoparasites, living in the webs of much larger spiders and stealing from them. It’s a surprisingly widespread lifestyle (see Wikipedia for examples), but its dangers are obvious: the host might catch and eat the freeloader. In this case, we think that the Dewdrop is so light-footed that the St Andrew’s Cross doesn’t respond as it would to the struggles of worthwhile prey blundering into her web.
As I watched, the Dewdrop spider circled around his host, who had finished her meal and was preoccupied with unwrapping her prey before discarding the dry remains. Eventually, after timid approaches and panicky retreats, Dewdrop laid his fangs on her meal.
Whether he extracted any nutrition from it is doubtful, but at least he survived the attempt.
A little while later he was in the lower section of her web with fresh prey which was his to enjoy in peace. It had been caught in her web but it was far too small for her to bother with. This, of course is the other (and probably safer) way in which Dewdrop spiders benefit from their host’s work.
Sitting at my computer a few days ago, I was distracted by a tiny bug moving around on the screen. My first impulse was to identify it, and the way it moved, its body shape and what I could guess of its leg-count all said, “spider, not insect.”
My next impulse was to remove it without harming it, and this is the point at which things got really interesting: I discovered that it wasn’t on the screen at all, but inside it. That, naturally (for me, at least) called for a photograph. Out came the camera and the macro lens …
But that was a problem, too, because photographing anything small, moving, poorly lit, obscured by its surroundings, or under glass is a challenge, and this was all five.
A recent trip to Paluma Dam with the good people of Wildlife Queensland was enjoyable for the wildlife and just being in the rainforest but was far from strenuous. We walked across the dam wall and along a vehicular track to the west of the dam, took a side track to down to the dam shore, and returned the same way Continue reading “Walking in the Paluma rainforest”