Deluded zombies: induced behavioural modifications in a spider with leaf shelter web do not increase the survival of its parasitoid wasp

Description

Data from an experiment in which we evaluated the survival of pupae of the parasitoid Zatypota alborhombarta in modified and unmodified webs of Cryptachaea migrans (File: Data Parasitoid_Survival), as well as evaluations of the web modifications induced by the parasitoid in both parasitized and unparasitized spider hosts (File: Data Web_Modification). The data is provided in Excel (.xlsx) format.

Steps to reproduce

Behaviour modification We analyzed the web structure of C. migrans hosts to evaluate web design changes, comparing webs constructed by parasitized and unparasitized spiders. We analyzed 12 females of C. migrans parasitized by the second-stage larvae of Z. alborhombarta, 11 females parasitized by the third-stage larvae of Z. alborhombarta, and 12 unparasitized females. We considered second-stage larvae the individuals with segmented bodies and third-stage larvae the individuals with characteristic dorsal tubercles, absent in previous stages. To describe the web modification induced by the parasitoid larvae, we collected the spiders in the field from July 2016 to October 2017. We stored the individuals in polyethylene tubes and took them to the laboratory. All individuals were collected with their shelters (dry leaf). We quantified the components of webs of non-parasitized and parasitized spiders by second-stage larva 48 h after transferring the individuals to the triangular structure in the laboratory. Webs of spiders parasitized by third-stage larvae were described after the parasitoid larva killed the spider. To describe the web, we first covered it with cornstarch and photographed it. We evaluated changes in the number of vertical lines, the number of distal ends of gumfoot lines forked, the number of gumfoot lines, and the increase in the density of silk threads around the shelter's support thread. Parasitoid pupae survivorship in unmodified and modified webs To evaluate pupae survival in unmodified and modified C. migrans webs, we collected spiders parasitized by second-stage larvae and unparasitized spiders. The parasitized spiders were divided into two groups. In the first group (N=17), when the wasp larvae induced web modifications, we transferred the parasitized spiders from these webs to unmodified webs constructed by unparasitized spiders installed in other structures. We previously removed the resident spider from its unmodified web and released it on vegetation at least 1000 m away from the experimental area. In addition, in the second group (N=15), we removed the parasitized spiders from their original modified webs, kept them for 1 minute (same time spent to transfer the spiders of the first group between the webs) in 2 ml plastic microtubes and inserted them again in the same modified webs from they have been removed. After the death of the parasitized spider and subsequent cocoon building by the larvae in both groups of webs, the structures with webs and cocoons were inserted in the field. We positioned each web every 30 meters in line, which prevented the repetitions from being distributed in a small area. The repetitions were performed over time. All webs remained in these places for at least 14 days, which is a period sufficient for all adult Z. alborhombarta to hatch (T.G. Kloss, pers. observ.).

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