2019 Volume 22 Issue 1 Pages 11-23
Oviposition upon active predatory spiders is an arduous undertaking for spider-parasitoids (Ichneumonidae, the Polysphincta group of genera) in comparison with that towards phytophagous or saprophagous insect hosts, e.g., caterpillars, maggots or aphids. Here, various offensive oviposition behaviours of polysphinctines against spiders are reviewed. Although there are merely eight species behaviour of which are unravelled, they seem to be highly and uniquely adapted to spider-webs of each host spider. Several tactics, i.e., abrupt plunge, aggressive mimicry, pure ambush and creeping-up, have been recognized as a whole. There is a commonality among these tactics whereby the polysphinctines conservatively adopt careful ways to approach so that the spiders do not escape from the wasp (not being recognized as an enemy), rather than avoiding becoming prey to the spiders.
