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

Abstract

Current knowledge about polysphinctine parasite wasps' interactions with their spider hosts is very fragmented and incomplete. This study presents the host specificity of Zatypota percontatoria (Müller) (Hymenoptera: Ichneumonidae) and its adaptation to varying host availability. Two years of field observations show that Z. percontatoria is a stenophagous parasitoid that parasitizes only five closely related web-building spiders of the family Theridiidae (Araneae). Within the Theridiidae it attacks only species belonging to a small group of species, here called the “Theridion” group. These hosts have a similar biology, but are available at different levels of abundance and at different sizes over the season. Laboratory experiments showed that this wasp species ignores linyphiid, araneid or dictynid spiders and accepts only theridiid spiders of the “Theridion” group. In the field study, wasp females preferred older juvenile and sub-adult female spider instars with intermediate body size. Only 5% of the parasitized spiders were males. Parasitism in the natural population of theridiid spiders was on average 1.3%. Parasitism was most frequent on two species, Theridion varians Hahn in 2007 and Neottiura bimaculata Linnaeus in 2008. The parasitization rate was positively correlated with spider abundance. The wasp responded adaptively to seasonal changes in host abundance and host body size and shifted host preference according to the availability of suitable hosts during, as well as between, seasons. In spring and summer the highest percentage of parasitism was on T. varians and in autumn it was on N. bimaculata.

The ecological success of a social parasite increases with manipulation of collective host behaviour

“…Similar interspecific differences were shown in other host–parasite interactions, including amphipod–acanthocephalan (Tain et al ., ), spider–parasitoid wasps (Eberhard, ; Korenko & Pekár, ) and other ant–slavemaker systems (Bauer et al ., ). In some cases, parasites readily switch between host species, preferentially targeting the most abundant host (Korenko et al ., ), whereas in others, host preference reflects differences in the ability of parasites to manipulate host behaviour (Tain et al ., ). In our study system, parasite prevalence is higher in T. longispinosus populations, even in communities where T. curvispinosus is more abundant (Brandt & Foitzik, ).…”

Life history of the spider parasitoidZatypota percontatoria(Hymenoptera: Ichneumonidae)

“…percontatoria and their theridiid host have been studied by Korenko et al . () and Korenko and Pekár (). In these studies, the average prevalence of parasitism in Central Europe was observed to be 1.74–0.83%.…”

“…pinastri L. Koch, 1872, Phylloneta impressa (L. Koch, 1881), Neottiura bimaculata (Linnaeus, 1767), Platnickina tincta (Walckenaer, 1802), Heterotheridion nigrovariegatum (Simon, 1873) and Paidiscura pallens (Blackwall, 1834) (Korenko et al . ). Interactions between Z .…”

Megaselia scalaris(Diptera: Phoridae): an opportunistic endoparasitoid of the endangered Mexican redrump tarantula,Brachypelma vagans(Araneae: Theraphosidae)

“…Many species of spider are parasitized by a variety of insects (Eason et al 1967), most of which belong to the arthropod orders Hymenoptera and Diptera (Korenko et al 2011), as well as some nematodes (Poinar 1985(Poinar , 1987Penney & Bennett 2006), and kleptoparasitic spiders (Hénaut et al 2005). Considering only dipteran parasitoids, those in the family Acroceridae are the most representative (Schlinger 1993), although some species from the Tachinidae, Chloropidae, and Drosophilidae families also parasitize spiders (Eason et al 1967;Disney 1994).…”