Seasonal patterns of parasitism of the tropical spiders Theridion evexum (Araneae, Theridiidae) and Allocyclosa bifurca (Araneae, Araneidae) by the wasps Zatypota petronae and Polysphincta gutfreundi (Hymenoptera, Ichneumonidae)

Abstract

The rates of parasitism of Theridion evexum by the parasitoid wasp Zatypota petronae, and Allocyclosa bifurca by Polysphincta gutfreundi, were followed for two years. Parasitism of T. evexum was very low (mean 1.39+1.8%), and restricted to nearly seven months of the year. Parasitism of A. bifurca was higher (mean 7.8+7.6%), and did not show a seasonal pattern. Reproduction of the host spider T. evexum was highly seasonal, with only one, highly coordinated generation per year, while adults of A. bifurca were present year round. Short-term autocorrelation on parasitism rates over time at different sites suggest that P. gutfreundi tend to return to the same sites to hunt hosts over periods of a few weeks.

Host Specificity and Temporal and Seasonal Shifts in Host Preference of a Web-Spider ParasitoidZatypota percontatoria

“…The rate of parasitism on theridiid hosts by Z. percontatoria was relatively low in both years. This complements observations on other related species: 1.4% in Zatypota petronae Gauld parasitized on Theridion evexum Keyserling ( Barrantes et al 2008 ) and 5% in Zatypota albicoxa (Walker) parasitized on Parasteatoda tepidariorum (C.L.Koch) ( Tanaka 2007 ). In the study orchard, the frequency of parasitism did not exceed 6% throughout the season, except for the summer of 2007, when parasitism rate was 33% (sample in August).…”

“…In strictly specialized parasitoids, their life history is tightly coupled with that of their host species. Such parasitoids occur only in the habitat of their host and synchronize their development with them ( Barrantes et al 2008 ). Examples of rather specialized parasitoids include polysphinctine ichneumonids that attack spiders (e.g.…”

Incidence of Parasitoids and Predators on Eggs of Seven Species of Therididae (Araneae)

“…The occurrence of parasitoids year round may be related to the year-round presence of host spiders and egg sacs. A similar pattern was found for koinobiont spider parasitoids of other spider species in the same study area (Barrantes, Eberhard & Weng 2008). The seasonal changes in the incidence of parasitoids in the egg sacs of these two spider species is of changes in abundance and distribution of either hosts, parasitoids or both, but this result may also be affected by the relatively small sample size included in the analysis.…”

Maternal Care and Offspring Behaviour in Three Theridiid Species (Araneae, Theridiidae)

“…Maternal care is displayed by theridiids in many different ways, including protecting the egg sac (Bristowe, 1958;Viera et al, 2007), capturing prey for the offspring to feed upon (Bristowe, 1958), regurgitating to the offspring (Bristowe, 1958;Foelix, 1996;Viera et al, 2005Viera et al, , 2007, and accumulating the bodies of dead prey before the emergence of the spiderlings from their egg sac (Barrantes & Weng, 2007, 2008. Here, we describe the maternal care and offspring behaviours and occasional mortality of offspring associated with maternal care in Theridion evexum, Achaearanea tesselata (Keyserling) and Anelosimus studiosus (Hentz).…”