Selection of Bemisia nymphal stages for oviposition or feeding, and host-handling times of arrhenotokous and thelytokous Eretmocerus mundus and arrhenotokous E. eremicus

Abstract

Abstract. Host-handling behavior is an important aspect of parasitoid foraging behavior. When a parasitoid encounters a potential host, the handling behavior starts with the evaluation of the host and continues if the host has been judged acceptable. Host handling is usually terminated after egg laying or host feeding and host marking. Hosthandling behavior of an arrhenotokous population of two Eretmocerus species, E. mundus Mercet and E. eremicus Rose and Zolnerowich, along with a thelytokous population of E. mundus were compared under laboratory conditions. Several elements of host-handling behavior, including encountering, ascending, turning on host, descending, preening, egg laying, and host feeding were recorded. There were no correlations among the durations of these phases across parasitoid populations/species or host nymphal instars. Duration of different phases of host-handling behavior showed only slight and sometimes significant differences between different Eretmocerus populations/species. The actual laying of the egg had the longest duration of all host-handling behaviors, and was longer on third nymphal instars than on younger ones. Females of the three populations/species accepted the first three nymphal stages either for egg laying or for host feeding. Females spent a lot of time to make wounds in the host when preparing for host feeding, and eventually killed the host. The implications of these findings for the use of the different Eretmocerus populations/species in biological control are discussed.

DoesWolbachiainfection affect decision‐making in a parasitic wasp?

“…() stated for the first time that high rates of natural horizontal transfer occur between conspecifics in T. kaykai , when Wolbachia ‐infected and ‐uninfected T. kaykai larvae shared the same host and newly infected females thereafter produced daughters from their unfertilized eggs. As they produce only female progeny, the intrinsic rate of population growth is higher, even where the number of progeny per female is lower (Hohmann et al., ; Ardeh et al., ,b; Ramirez‐Romero et al., ). The thelytokous parthenogenesis induced by the infection increases the spread of Wolbachia .…”

Host‐feeding of three parasitoid species on Bemisia tabaci biotype B and implications for whitefly biological control

“…Non‐concurrent destructive host feeders are considered to be superior biological control agents to non‐host feeders (Jervis & Kidd, 1986; Jervis et al., 1996). Most whitefly parasitoids belong to this type of host feeders (van Lenteren et al., 1996; Videllet et al., 1997; Ardeh et al., 2005). However, there are no detailed studies on their capacities for host‐feeding and their influence on whitefly suppression.…”

Retrospective analysis of a classical biological control programme

“…Life tables may not have adequately quantified host‐feeding, and thus additional mortality imposed by either the native or exotic parasitoids. This behaviour is common in aphelinid parasitoids attacking a wide range of insect species, including those here (Ardeh, de Jong, & van Lenteren, ; Zang & Liu, ). Life table observations failed to detect any obvious evidence of host‐feeding on B. tabaci nymphs (Naranjo & Ellsworth, ), although this mortality could have, on occasion, been incorrectly captured in the unknown category.…”