Attraction behaviour of three entomopathogenic nematode species towards infected and uninfected hosts

Abstract

Entomopathogenic nematode infective juveniles are likely to encounter both uninfected and infected insects and host quality depends on the stage of the infection. We hypothesized that nematode response to infected hosts will change over the course of an infection. Here, we tested this hypothesis by focusing on the influence of host infection status on long-range attraction to host volatile cues. The attraction response of 3 nematode species (Steinernema carpocapsae, S. glaseri and S. riobrave) with different foraging strategies to infected and uninfected insects (Galleria mellonella and Tenebrio molitor) was tested at 24 h intervals from start of infection to emergence of infective juveniles from depleted host. As expected, based on their foraging strategies, S. carpocapsae was not very responsive to hosts, S. glaseri was highly responsive and S. riobrave was intermediate. Generally, the level of attraction did not change with time after infection and was similar between infected and uninfected hosts. An exception was S. glaseri infected T. molitor, which tended to be less attractive to S. glaseri than uninfected hosts. These results suggest that any influence of host infection status on infection behaviour is occurring at subsequent steps in the host-infection process than host attraction, or involves non-volatile cues.

How maize root volatiles affect the efficacy of entomopathogenic nematodes in controlling the western corn rootworm?

“…Error bars represent the standard error of mean roots on which they can survive (Moeser andVidal 2004, Oyediran et al 2005). In contrast, EPN will also be effective against WCR larvae on roots of other plants Gaugler and Campbell 1991;Rae et al 2006;Ramos-Rodriguez et al 2007). …”

Comparative susceptibility of larval instars and pupae of the western corn rootworm to infection by three entomopathogenic nematodes

“…Nematodes orientate towards stimuli such as, carbon dioxide, long chain alcohols or thiazoles (Gaugler and Campbell 1991;O 0 Halloran and Burnell 2003), host excretory products (Schmidt and All 1978;Ramos-Rodríguez et al 2007), temperature gradients (Byers and Poinar 1982) and herbivore-induced plant volatiles (Rasmann et al 2005). The ability of EPNs to use these cues varies between species with different foraging strategies.…”

Host-seeking behavior of the Heterorhabditis amazonensis nematode in response to stimulant sources1

“…According to Ramos-Rodriguez et al (2007), nematodes use various chemical cues to find hosts, and these substances, such as CO 2 , may not necessarily be released by the host. Therefore, these cues can be unreliable, because they are emitted by many different sources, including non-host insects, and in various quantities.…”