Olfactory cues used in host‐habitat location and host location by the parasitoid Cotesia urabae

Abstract

There is a growing body of evidence that many hymenopteran parasitoids make use of olfaction as the primary mechanism to detect and locate hosts. In this study, a series of bioassays was conducted to investigate the orientation behaviour of the gum leaf skeletonizer larval parasitoid Cotesia urabae Austin & Allen (Hymenoptera: Braconidae) in both Y-tube and four-arm olfactometers. In a Y-tube olfactometer, male C. urabae were attracted only to virgin conspecific females. Host-plant leaves, damaged leaves, host larvae, and host larvae feeding on leaves were highly attractive to female C. urabae, whereas host frass and conspecific males were not. The multiple-comparison bioassay conducted in a four-arm olfactometer clearly indicates that C. urabae females were significantly more attracted to the host Uraba lugens Walker (Lepidoptera: Nolidae) larvae feeding on Eucalyptus fastigata H Deane & Maiden (Myrtaceae) leaves than to any other of the odour sources tested. The results of this study show that C. urabae individuals responded to chemical cues specific to the host plant and target host insect, and support hypotheses that unreliable cues are not utilized for host location by specific natural enemies.

Tamarixia radiata Behaviour Is Influenced by Volatiles from Both Plants and Diaphorina citri Nymphs

“…These investigations indicated that T. radiata males may forage for females in response to a volatile pheromone produced by the female. Similar findings have been observed with other parasitoid species [36].…”

“…Following this, female T. radiata may then refine their search by utilizing kairomones emanated by D. citri larvae nymphs from the host habitat (short-range searching). Studies conducted with Cotesia urabae Austin & Allen have also found that parasitoid wasps are capable of responding to volatiles emanated by plants of their hosts and the insect hosts themselves [36]. Specifically, Avila et al [36] observed that female C. urabae showed attractions to odour sources emitted by Eucalyptus fastigata Deane & Maiden leaves, their host larvae ( Uraba lugens Walker), the target plant–host complex, and E. fastigata leaves from feeding damage caused by their host larvae [36].…”

Behavioral responses of Anagrus nilaparvatae to common terpenoids, aromatic compounds, and fatty acid derivatives from rice plants

“…Successful location of oviposition sites by parasitoids requires the ability to perceive physical and chemical cues that indicate the presence of resources (Schröder & Hilker, ). It is widely accepted that chemical stimuli, such as infochemicals, are of great value for parasitoid foraging and survival (Tamiru et al., ; Avila et al., ).…”

Host‐related volatile cues used by a parasitoid wasp during foraging for its woodboring host

“…Parasitoids attack herbivorous hosts that can display various degrees of concealment (i.e., fully exposed, leaf miners, plant galleries , stem‐, wood‐, or seedborers) and while searching for them, they have to contend with the reliability–detectability problem (Vet & Dicke, ; Godfray, ): host‐derived stimuli are the most reliable indicators of host presence but their detectability is selected to be low; conversely, stimuli from plants on which herbivores feed may provide information which is readily detectable but not necessarily reliable in indicating herbivore presence. Particularly, plants release blends of volatile compounds in response to damage by herbivores (Hare, ), that are highly detectable by parasitoids in the long‐range search process (Turlings et al., ; Poelman et al., ; Avila et al., ). Plant volatile blends can be diverse in their chemical composition and parasitoids cope with this chemical complexity by reacting to a limited set of volatiles released by herbivore‐damaged plants.…”