Sunday, April 10, 2011
Australian of the Week: Net-casting Spider
Winter has somewhat relaxed its grip these last two weeks, enough so that at least one blue-bottle fly. probably Protophormia terraenovae Robineau-Desvoidy, 1830, has been on the wing. After work I’ve been sitting in a lawn chair in a spot of sun in a puddle of snowmelt determined to generate the first Vitamin-D of 2011 and the bluebottle stops by to see if I’m winter kill or not. You’d think from the species name, that the fly (aka Northern Blowfly) would be restricted to the New World, but it is holarctic in distribution and relatively well known for its forensic uses and myiasis problems in livestock and wildlife.
The fly is too wary for me to get close enough for a good shot with my point and shoot camera, but is familiar enough to induce daydreams about what might happen to the fly if it were in my former backyard in Brisbane, where a striking diversity of spiders were in residence year-round. One of my favourites was the Net-casting Spider, a species of Deinopis, probably Deinopis subrufa L. Koch, 1879. These are ambush predators that dangle from a scaffold web by their back two pairs of legs while holding a densely woven net in the front two pairs. Any insect that wanders or flies too close is snared and eaten. This behaviour has also earned them the name Retarius Spider from the Roman gladiators who fought with a net, trident, and dagger. Another name is Ogre-faced Spider – because of the very large median eyes that no doubt help coordinate the net-casting. We don’t seem to have a good frontal picture, but Robert Whyte has posted a striking portrait on flicker.
April 5th marked the first observation of a Milbert’s Tortoiseshell Butterfly (Aglais milberti) in the backyard with its bright colours and intriguing white tips to its antennae. A lone Ring-billed Gull showed up on 31 March and a Robin yesterday (9 April), so in spite of the deep snow pack and cooler than normal temperatures, spring does seem to be in the air. In my records (which only go back to 2005), the Ring-billed Gulls always show up in the last week of March – and since they are large and loud, they are hard to miss. The tortoiseshell sightings are more variable (5-17 April), but these depend on the happy coincidence of a sunny day and time for me to enjoy it. The Robin, and a couple of Honkers that showed up on April Fool’s Day, are both within the two week window in my records, so at least the animals around here think spring is coming at more or less the normal time. Time to set up a couple of blue bird houses at the Moose Pasture and then start shoveling the snow away from the house foundations. The water level is already getting close to the top of the holes in the basement floor.