Two new species of parasitic wasp have been identified in Portugal, and both parasitize the same species of spider.
The spider Zodarion styliferum belongs to the largest genus of ant-eating spiders, just one of over 100 species. It spends the day sleeping, only emerging at night to hunt its sole source of food. But it doesn’t sleep just anywhere – it builds itself an “igloo” using rocks and dead wood. This miniature house may protect it against a harsh environment or predators, but it’s no defence against the parastoid wasps Calymmochilus dispar and Gelis apterus.
Unfortunately for juvenile Z. styliferum, the wasps are perfectly evolved to negate the walls. When the spider is sleeping during the day, they push their narrow ovipositors (seen coiled beneath the wasp’s abdomen) through the cracks and gaps of its shelter. The wasps lay their eggs on the juvenile (at some point, it is immobilised) and feed on it.
But it’s not only the food source the wasps end up with – they get a nice home to pupate in. The wasps differ in their metamorphoses; while G. apterus spins itself a cocoon before pupating, C. dispar does not. It seems a tragic irony that while the spider’s house cannot protect it against the wasps, it does an excellent job of protecting the wasps themselves.
To read the paper: http://bit.ly/XjMl1U
Photo: Female G. apterus. Credit to Stanislav Korenko.