Dewdrop spider living on the edge

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.

Argyrodes antipodianus
St Andrew’s Cross with a Dewdrop spider at the top of the photo

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.

Argyrodes antipodianus
Dewdrop Spider, male

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.

Dewdrop spider stealing from St Andrew's Cross
Dewdrop getting closer to a meal
dewdrop and standrew's cross spiders
Dewdrop reaching for a the host’s prey
dewdrop
Yes, really!

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.

Dewdrop spider and prey
Dewdrop spider and prey

Peak butterfly season

Rain makes the plants grow and provides ideal conditions for caterpillars and other vegetarian insects so we’re now in peak butterfly season.

One very slow walk around my garden was enough for me to take the photos you see below. I missed the Common Crow (old pic here), which we see often, and the Orchard Swallowtail and Cairns Birdwing, which are fairly regular visitors, but otherwise it’s a good overview of the larger species we see at this time of year.

Junonia hedonia
Brown Soldier or Chocolate Argus, Junonia hedonia
Cupha prosope
Australian Rustic, Cupha prosope

Continue reading “Peak butterfly season”

The burrowing wasp

We’ve had a couple of big mounds of mulch in our garden since the stump-grinding people did some work for us almost a year ago. “Leave us some mulch,” I said, and they did.

We have gradually spread it around and dug it in, but we’ve had a surprising amount of help from little friends – mostly big fat white grubs which are scarab larvae.

A big black wasp has been keen to help, too.

Flower Wasp
Wasp digging into the mulch

Continue reading “The burrowing wasp”