Behavioral manipulation in two sheet web weaver-spider by the parasitoid wasp, Eruga unilabiana Pádua & Sobczak, 2018 (hymenoptera: Ichneumonidae)

The ability of some organisms to manipulate the behavior, physiology, and morphology of other individuals to increase the chances of survival and reproduction is well known among animals with a parasitic lifestyle. In the present study we (i) report the interaction between the parasitoid wasp Eruga unilabiana and the host spider Eurymorion sp. (Linyphiidae) for the first time (plus Sphecozone sp. (Linyphiidae)), (ii) describe the normal and cocoon webs of Eurymorion sp. induced by larvae of the penultimate instar of E. unilabiana, (iii) quantify the differences between the structures of normal and cocoon webs of Eurymorion sp. and Sphecozone sp. spiders, and (iv) describe the behavior of two spider species under influence of the penultimate instar larvae of E. unilabiana. The cocoon webs built by parasitized Eurymorion sp. are structurally similar to those of Sphecozone sp. induced by the same parasitoid species. The areas of the sheets and the length of the interception threads of the cocoon webs were significantly smaller than those of normal webs. Several individuals of the two species of host spiders are induced to abandon their normal webs to build a cocoon web from scratch, a rare behavior in non-parasitized individuals.