A very small drama on Castle Hill

Castle Hill from the Magnetic Island ferry
Castle Hill from the Magnetic Island ferry

Castle Hill is an immense mass of pink granite rising above the city. Beloved by tourists, joggers and landscape painters, it is a challenging environment for wildlife because the soil (where there is any) is so thin. Rainwater drains off almost instantly, so the vegetation struggles to survive and there aren’t many herbivores to feed the carnivores. Nevertheless, on Sunday I spent almost an hour in a little patch of open scrub near the summit, watching to see what was around, and was well rewarded.

There were grasshoppers, butterflies (Blue Tigers, Migrants, Crows and a few others), a couple of bee-flies, a baby mantis and lots of ants (links here take you to these insects on my flickr photostream), but the spiders drew my attention. There were odd little patches of silk in a few seed-heads of the tall grass and I pulled one apart to find a small pale-gold spider, while a similar but bigger patch in a knee-high sandpaper fig tree was home to what looked like a whole family (a female guarding her egg-sac and a smaller adult which could have been the male) of grey-brown spiders. A slim grey spider with enormously long legs appeared on the trunk of a poplar gum and wandered off again, and I watched the later stages of a deadly attack on one spider by another.

The attacker was a jumping spider (Salticidae, perhaps a Sandalodes) and its prey was a Lynx (Oxyopes macilentus). Both are predators, but the Lynx is an ambush hunter, typically waiting for prey to come within reach, while jumping spiders are roving hunters. In this case it looks like the jumping spider, the larger of the two, had chanced across the Lynx and lived up to its name; the Lynx offered very little resistance to its larger attacker.

How big are they? Not very big at all: perhaps 11 mm and 7 mm. If I hadn’t chosen to sit quietly and look around,  I wouldn’t even have noticed them in the grass.

two spiders
The jumping spider already has the advantage
two spiders
Nearly over. The Lynx has lost a couple of legs
two spiders
It’s easy to feel sorry for the loser

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