Use of parasite regulation of host endocrinology to enhance the potential of biological control

Abstract

The implications of parasite regulation of host endocrinology for successful biological control have not been fully appreciated. Insect parasites regulate host metamorphosis in a number of different ways. For a given host (pest) situation, each form of host regulation has its own advantages and disadvantages. Careful selection of a parasite based upon its mode of host regulation can enhance the potential for biological control success. A basic knowledge of the endocrine basis for parasite regulation of its host will enable prediction of whether a parasite can regulate, and survive in, a host to which it has not been previously exposed.KEY-WORDS : Parasite regulation, host endocrinology, biological control.Insect parasites play a central role in the theory and practice of biological control of insect pests. Important behavioral and physiological properties of the parasite are conceptualized as I) host habitat finding, 2) host finding, 3) host acceptance, and 4) host suitability. Vinson (1975) distinguished between the suitability of the host as a template for parasite growth and the ability of the parasite to regulate the physiology of the host to keep that template suitable.The importance of the physiological aspects of the host-parasite interaction has been perceived only by some biological control authorities. DeBach (1974) stated that biological control problems must be solved by basic research including physiological studies. Achieving an understanding of the steps leading to selection and utilization of a specific host "... is one of the most important problems involved in the scientific investigation of biological control" (Doutt, 19641. Furthermore, "It appears very likely that if all facts were known, physiological unsuitability of natural-enemy species to their hosts has been the cause of a great many of the failures in colonization of imported species" (DeBaeh & Bartlett, 1964).Unfortunately, little research emphasis has been given to the physiological basis for host regulation, or how such knowledge can aid in successful biological control. Research papers, review articles and research grants rarely give real or hypothetical examples of how this basic knowledge can give more benefits than empirical observations.Possibly such examples were not given in the past because the endocrine basis for insect development and metamorphosis is only recently becoming understood, and these advances often are published in journals not scrutinized by biological control researchers. The purpose of this review is to 1 ) outline ways in which hosts and parasites do or can interact endocrinologically, 2) enumerate for biological control researchers advances in basic physiology which

Developmental responses of Trichoplusia ni (Lepidoptera: Noctuidae) to parasitism by the ectoparasite Euplectrus plathypenae (Hymenoptera: Eulophidae)

“…Parasitoid-host interactions have a profound effect on the behavior and development of the parasitized hosts. The interactions that have been observed between host larvae and parasitoids include 1) temporary or permanent paralysis, 2) alteration of the length of an instar, 3) induction of supernumerary instars, and 4) induction of precocious development [1,2]. Disruption of developmental events in hosts by parasitoids has been most thoroughly studied in the Lepidoptera [3-10; for reviews, see 1,ll-151.…”

Isomeric and quaternary properties of homogenous 33 kDa protein from the venom of chelonus near curvimaculatus

“…Paralyzing components of wasp venoms have been used in basic studies as probes of the insect neuronal synapse 171. Such venoms have been proposed for practical use in insect control [8][9][10][11]. A wide variety of experimental uses on nonparalyzing wasp venoms is suggested by their wide variety of effects [ill. Nonparalyzing venoms have been implicated in the survival of larval endoparasites , in endocrine disruptions in the host 1151, and in biochemical interactions with polydnaviruses [16].…”