Host recognition parasitoid

Strand, M. R. and Vinson, S. B. Source (1982b) and characterization of a host-recognition kairomone of Thelonus heliothidis an egg parasitoid of Heliothis virescens. Physiol. Ent., 7, 83-90. 

Vinson, S. B. (1975b) Source of material in the tobacco budworm involved in host recognition by the egg-larval parasitoid, Chelonus texanus. Ann. ent. Soc. Am., 68, 381-4. 

Host recognition by parasitic Hymenoptera also can be a complex process involving a series of behaviors after initial host contact that must be completed in sequence before an egg is laid. One such sequence is illustrated in Figure 5.7, which diagrams the processes by which Aphytis melinus, a parasitoid used for biological control of California red scale, Aonidiella aurantii, first identifies a potential scale insect species as a potentially suitable host, then assesses the individual quality of that host for utilization (Luck et al. 1982). Egg deposition is the final event of a chain of other behaviors that must be completed in sequence. The series can be broken in several placed and restarted, but no steps can be skipped. 

Several other examples of host plant recognition by hymenopteran parasitoids have been described recently. Six species of aphid parasitoids, Aphidius ervi, Trioxys sp., Praon sp., Aphelinus flavus, Lysiphlebus fabarum, and Aphidius rophalosiphi were most strongly attracted to their host aphid in combination with the damaged host plant [62]. For A. rhopalosiphi, three wheat volatiles were... 

The external cuticle of insects is covered by a waxy layer composed of mixtures of hydro-phobic lipids that include long-chain alkanes, alkenes, wax esters, fatty acids, alcohols, aldehydes, and sterols. The primary purpose of this layer is to maintain water balance and prevent desiccation, as described in Chapter 6, but many of the cuticular lipid components have important secondary roles as intraspecific contact chemical signals (pheromones). These roles include species and sex recognition during reproductive interactions, and nestmate recognition and other colony organization functions in social insects. Thus, these compounds are essential mediators of insect behaviors. Cuticular compounds are also exploited by parasitoids and predators as interspecific contact cues (kairomones) to aid in host location. 

There is little doubt that chemicals play an important role in the internal defense and counterdefenses that have evolved during the evolution of the various parasitoid-host relationships. Currently too little is known about the chemicals involved in internal recognition and defense to develop any overall concepts. 

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