The function of spider egg sacs in relation to parasitoids and predators, with special reference to the Australian fauna

Systematics and biology of the aberrant intertidal parasitoid wasp Echthrodesis lamorali Masner (Hymenoptera : Platygastridae s.l.): a parasitoid of spider eggs

“…Baeus, Echthrodesis, Mirobaeoides). Some of the latter possess highly modified tarsal claws that facilitate access through the sticky silk (Austin 1985). Males of Echthrodesis have the specialised body form of females with extremely reduced wings (although they are larger than in the female), a sub-fusiform body and subsessile metasoma.…”

“…However, E. lamorali might rarely or never be physically immersed in water due to the air trapped within the egg sac and spider retreat inside limpet shells, which might provide sufficient air during submersion at high tide. Spider egg sacs and silk retreats play a critical role in preventing desiccation of eggs and juvenile spiders (Austin 1985(Austin , 1988bHieber 1992) and, hence, are likely to be sufficiently hydrophobic to keep water out. With the asynchronous development of egg clutches within a single egg sac, Echthrodesis can complete its life cycle protected inside a single spider retreat and only needs to expose itself to the external environment when it needs to locate new hosts.…”

Occurrence of Parasitoid Wasps, <em>Baeus</em> sp. and <em>Gelis</em> sp., in the Egg Sacs of the Wolf Spiders <em>Pardosa moesta</em> and <em>Pardosa sternalis</em> (Araneae, Lycosidae) in Southeastern Idaho

“…Larval endoparasites that consume spiders eggs are classified as parasitoids (Roberts and Janovy 2000) with the most speciose family of parasitoid wasps being the Ichneumonidae (Godfray 1994). To parasitize a spider egg sac, wasps insert their ovipositor into the wall of the egg sac and lay eggs which develop into larvae and predate the spider eggs (Austin 1985).…”

Egg sac construction by folding dead leaves in Pozonia nigroventris and Micrathena sp. (Araneae: Araneidae)

“…Protection is not absolute, and spider eggs frequently suffer high mortality from organisms such as ants, wasps, flies and birds (Austin 1985;Hieber 1992). Egg sac construction varies widely among different spider taxa (Kullmann 1961;Robinson & Robinson 1973, 1976Eberhard 1980;Manuel 1984;Austin 1985;Levi 1985;Barnes et al 1992;Bukowski & Christenson 1997;Guarisco 2001;Gheysens et al 2005).…”

“…Keywords: Canopy spider, convergent behavior, oviposition, predator defense Spider egg sacs protect eggs from damage by both biotic and abiotic factors (Austin 1985). Protection is not absolute, and spider eggs frequently suffer high mortality from organisms such as ants, wasps, flies and birds (Austin 1985;Hieber 1992).…”