Do the food availability conditions influence the stage-specific prey choice and predation attributes of agroecosystem-inhabiting spiders?

Abstract

Present study was designed to assess the predation attributes of the hunting (Oxyopes javanus and Pardosa sumatrana) and web-weaving (Neoscona theisi and Tetragnatha javana) spiders on the wingless and winged stages of the economically important wheat aphid (Sitobion avenae) pests under varying prey quantity conditions. The experiments were carried out in two parts. First part included optimization of the experimental prey conditions (scarce/ optimal/ abundant) per spider species. The second part assessed the consumption rate, conversion efficiency and growth rate of each of the four spider species under fluctuating experimental prey conditions. Results revealed that: (1) irrespective of the spider species, predation attributes (viz. consumption rates, conversion efficiencies and growth rates) were highest on scarce prey and lowest on abundant prey; (2) amongst the four spider species, larger spiders (i.e. N. theisi and O. javanus) had higher prey consumption and utilization efficiencies over the smaller ones (T. javana and P. sumatrana); and (3) all species of spiders utilized higher biomass of wingless as compared to winged morphs under optimal and abundant conditions but displayed no such significant differences in consumption patterns under scarce conditions. The present results therefore reveal that the four studied spider species exhibit compensatory feeding under prey scarce conditions. However, larger species are more efficient in overcoming scarce prey conditions than the smaller species. Since spiders have enormous potential as biological control agents the results would be of significance in the management of wheat aphids. © 2022, International Society for Tropical Ecology.