Cardiochiles nigriceps

Behavioral and chemical evidence for signal specificity was also obtained by De Moraes et al. (1998). They found that Cardiochiles nigriceps, a parasitoid that specializes on Heliothis virescens, is much more attracted to plants attacked by its host than by plants attacked by the closely related non-host H. zea. Volatile collections... 

Syvertson, T.C., Jackson, L.L., Blomquist, G. J. and Vinson, S. B. (1995). Alkadienes mediating courtship in the parasitoid Cardiochiles nigriceps (Hymenoptera Braconidae). J. Chem. Ecol., 12,1971-1989. 

Hydrocarbons with methyl branching at C-ll to C-13 were isolated from Heliothis virescens (Noctuidae, Lepidoptera) 229). These compounds release a host-seeking behavior in the braconid Cardiochiles nigriceps, a Heliothis parasit. These kairomones were prepared in 1975 by Vinson et al. 229) by Wittig methylenation of the corresponding methyl ketones and subsequent catalytic hydrogenation 229). 

Vinson, S.B., R.L. Jones, P.E. Sonnet, B.A. Bierl, and M. Beroza Isolation, Identification and Synthesis of Host-Seeking Stimulants for Cardiochiles nigriceps, a Parasitoid of Tobacco Budworm. Entomol. Exp. Appl. 18, 443-450 (1975). 

Larval parasitoids respond to silk, frass, volatiles, cuticular components, and glandular secretions (Weseloh, 1981). For example, Cardiochiles nigriceps responds to hydrocarbons in the mandibular glands of H. virescens (Vinson, 1968), Apanteles melanoscelus responds to the silk produced in labial glands of gypsy moth (Weseloh, 1977), and several species respond to host feces. 

The ability to discriminate also appears to be influenced by experience (van Lenteren, 1976). As shown by van Lenteren (1976), inexperienced females may superparasitize many hosts until they encounter unparasitized hosts and learn to discriminate. It also appears that location of the host may be a matter of experience. Female Cardiochiles nigriceps are more likely to search for and attack hosts if they have previously encountered a host than inexperienced females (Strand and Vinson, 1982a). 

Vinson and Scott (1975) found DNA-containing particles in the calyx of Cardiochiles nigriceps. Similar particles discovered in several species of braconids and ichneumonids are viral, invade host tissues, and may have profound effects on the host (see Stoltz and Vinson, 1979, for a discussion). These viruses have been implicated in affecting growth (Vinson et al., 1979), hemolymph trehalose levels (Dahlman and Vinson, 1977), and suppression of the host s immune response toward the parasitoid s progeny (Edson et al., 1981). It is anticipated that additional host regulatory functions of these viruses will be found. 

Strand, M. R. and Vinson, S. B. (1982a) Behavioral response of the parasitoid, Cardiochiles nigriceps to a kairomone. Ent. expt. appl., 31, 305-15. 

Vinson, S. B. (1968) Source of a substance in Heliothis virescensihdX elicits a searching response in its habitual parasite, Cardiochiles nigriceps. Ann. ent. Soc. Am., 61,8-10. 

Vinson, S. B., Jones, R. L., Sonnet, P., Beirl, B. A. and Beroza, M. (1975) Isolation, identification and synthesis of host-seeking stimulants for Cardiochiles nigriceps, a parasitoid of the tobacco budworm. Ent. exp. appL, 18, 443-50. 

Several saturated C32, C33, and C34 hydrocarbons with methyl branches in the Cl 1 -13 positions have been identified from the tobacco horn-worm (Heliothis virescens) (Lepidoptera Noctuidae) that elicit a hostseeking response of its parasitoid, Cardiochiles nigriceps. These kairo-mones have been synthesized by Vinson et ai (170) using appropriate methyl ketones and Wittig reagents followed by catalytic reduction. 

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