Host recognition by entomopathogenic nematodes: Behavioral response to contact with host feces

Abstract

Host recognition by entomopathogenic nematodes may occur through contact with insects' excretory products, cuticle, or gut contents. We analyzed the behavioral responses of four species of entomopathogenic nematodes during contact with feces of natural or experimental hosts. Host recognition by nematodes was manifested in alterations in the frequency and/or duration of one or more search parameters including forward crawling, headwaving, body-waving, stopping, backward crawling, head-rubbing, and headthrusting.Heterorhabditis bacteriophora andSteinernema glaseri showed behavioral responses to contact with feces of their natural hosts,Spodoptera exigua (Lepidoptera) andPopillia japonica (Coleoptera), and to the experimental hosts,Acheata domesticus (Orthoptera) andBlatella germanica (Blatteria).Steinernema carpocapsae responded only toB. germanica feces, whereas5. scapterisci did not significantly respond to any of the insect species. During contact with cockroach feces, all nematodes, exceptS. scapterisci, showed avoidance behavior. We suggest that ammonia present in cockroach feces is inhibitory to nematodes. Specific host recognition by entomopathogenic nematodes may be an important mechanism to maintain host affinities.

Movement of Heterorhabditis amazonensis and Steinernema arenarium in search of corn fall armyworm larvae in artificial conditions

“…The infective juveniles can use environmental cues to locate the host. Some of these stimuli are the concentration of CO 2 in the environment (Gaugler et al, 1980;Lewis et al, 1993;Lewis, 2002), the vibration caused by the host in the substrate (Torr et al, 2004), temperature gradients (Burman and Pye, 1980;Byers and Poinar Jr., 1982), the presence of an electric current (Shapiro-Ilan et al, 2009), and the presence of chemical compounds (Pye and Burman, 1981;Shapiro et al, 2000) such as the contents of the digestive tract of the insect (Grewal et al, 1997) and its excretion products (Schmidt and All, 1979;Grewal et al, 1993). The presence of these factors increases the chance of infective juveniles to find the host.…”

Steinernema carpocapsae: Poststorage Infectivity and Sex Ratio of Invading Infective Juveniles

“…The basic foraging strategy of Steinernema carpocapsae has been purported to be that of an ambusher (i.e., sit-and-wait behavior) (12,14,27) and tends to become quiescent with a straight posture when host cue such as CO2 (7,28) , feces (12,30) or larval plasma (25) are not available. The positive responses of IJs to such cues, if any, were at most 20% others were indifferent (23).…”

Behavioral ecology of entomopathogenic nematodes

“…Since penetration into non-suitable hosts is a dead end for that speciWc nematode genotype, it can be expected that nematodes recognize suitable hosts and that the response to host-associated stimuli and the ultimate success in establishing and propagating in a host is correlated. This was partially found for S. glaseri, S. carpocapsae, S. scapterisci, and H. bacteriophora with the hosts Spodoptera exigua (Hübner), Popillia japonica Newman, Blatella germanica (L.), and Achaeta domestica (L.) (Grewal et al, 1993a). The reaction of S. carpocapsae to contact with the integument of nine diVerent insect species was studied by Lewis et al (1996).…”