Sources of possible host regulatory factors in Cardiochiles nigriceps (hymenoptera: Braconidae)

Abstract

Both larvae and teratocytes liberated upon hatching from the eggs of the endoparasitoid Cardiochiles nigriceps Viereck were found to release proteins into their surrounding environment as they develop. Teratocytes were found to synthesize and release a number of proteins into culture media in which they were incubated. The proteins released differed among the different teratocyte ages. Larvae were also found to release proteins into the culture media in which they were incubated. Ligation of the head or anal vesicle altered the protein pattern found in the media. The results demonstrate that both larvae and the associated teratocytes release proteins that may have important functions in the parasitoidhost interaction. 0 1994 ~i~e y -~i s s , Inc.Key words: parasitoid, protein secretions, teratocytes, parasitoid larvae INTRODUCTIONInsects, following parasitism by parasitoid Hymenoptera, are either paralyzed or, if they grow and develop, the growth and developmental patterns are often altered. These pathologies, as discussed by Doutt [ 11, are not solely due to the physiological response of the host to the invader, but as discussed by Vinson and Iwantsch [2], are often due to factors released by the parasitoid that alter the physiology of the host in specific ways. Thus, the suitability of an insect to serve as a host for a particular parasitoid depends on constraints that the host represents [3] and the ability of the parasitoid to alter the physiological environment that the host represents. In some situations, and for some host processes, the developing parasitoid must conform to the physiological conditions of the host [4]. In other cases or for other processes in the same host, the parasitoid has evolved mechanisms that alter the host's immediate physiological environment [5-81. Acknowledgments: Approved as TA 30750 by the Director of the Texas Agricultural Experiment Station. Appreciation is extended to Zac Shawhan for insect colony maintenance.Received February 4, 1993; accepted April 6, 1993. 0 1994 Wiley-Liss, Inc. 198Vinson et al.Alteration of the physiological environment within which the parasitoid must develop involves both the injection and release of factors into the host [31. There are two basic sources of these factors. The first group is the parental derived factors that include the poison gland [9-111, calyx region of the lateral oviducts [12,13], the epithelium of the common oviduct [14], or the follicular epithelium [15,161. The second group is the progeny derived factors that include teratocytes and larvae that hatch from the egg [3]. Teratocytes are cells of the embryonic membrane of the parasitoid egg that are released upon hatching into the hemocoel of the host. The developing larvae are also a possible source of host regulatory factors.The larvae of Pimpla turionellae L. and ltoplectis conquisitor Say discharge secretions from their anus [24-271. These secretions have been reported to alter DOPA metabolism, and to have antibacterial and antifungal properties [24,27].Here we examin...

Polydnavirus of Campoletis chlorideae: Characterization and temporal effect on host Helicoverpa armigera cellular immune response

“…When the larva has emerged in the host, the parasitoid perhaps escapes from encapsulation by other mechanisms. It has been proved Braconids C. congregata and Cardiochiles nigriceps secrete proteins to modulate the host immune response (Beckage, 1993;Vinson et al, 1994). Calyx fluid (0.1 or 0.5 female equivalent) injected 24 h earlier failed to suppress the encapsulation of transplanted Sephadex, but could successfully suppress the encapsulation of washed eggs.…”

Feeding suppression in the tobacco hornworm, Manduca sexta: costs and benefits to the parasitic wasp Cotesia congregata

“…The afflicted insects will respond to tactile stimulation, but they do not feed (Vinson and Iwantsch 1980;Fouad et al 1994). Although parasitoid larvae can secrete compounds into their host (Führer and Willers 1986;Vinson et al 1994), it is not known whether C. congregata secrete compounds capable of suppressing host feeding.…”

Host regulation by the aphid parasitoid Aphidius ervi: the role of teratocytes

“…This activity integrates the action of the venom in the host castration process, and plays an increasingly important role when the parasitization occurs on later instars. This may partly explain the variation in the host quality of different pea aphid instars, which is a nonlinear function of the host size when parasitized (Sequeira & Mackauer, 1992a,b, 1994. However, this is accomplished through different dynamic changes of the host biochemical profile and metabolism, which are related to the host instar at parasitization (Pennacchio et al, 1995).…”