VIRUS PARTICLES FROM THE REPRODUCTIVE TRACT OF THE FEMALE PARASITOID HYPOSOTER EXIGUAE (VIERECK) (HYMENOPTERA: ICHNEUMONIDAE): PHYSIOLOGICAL EFFECTS ON THE LARVAE OF THE CABBAGE LOOPER, TRICHOPLUSIA NI (HUBNER) (LEPIDOPTERA: NOCTUIDAE)

ROBERT MICHAEL KENNEDY, Fordham University

Abstract

Hyposoter exiguae calyx virus (HeCV) is purified on a continuous (10%-50% w/v) sucrose density gradient by centrifugation at 25,000 X g. Two criteria for purity were established: examination of the preparation in the electron microscope and electrophoresis of the particles through a 3%-6% discontinuous gradient polyacrylamide gel.^ Injection of healthy T. ni larvae with a purified preparation of HeCV causes a significant reduction of larval weight gain. Although depressing larval weight gain for six days the injection of HeCV does not prevent pupation. HeCV injected larvae pupate and give rise to normal adults, albeit four days later than the controls. The activity of the virus with regard to suppression of larval weight gain is destroyed by treating the HeCV preparation with the detergent NP-40.^ Measurements of larval oxygen consumption, and index of metabolic rate, showed that injection of T. ni larvae with a purified preparation of HeCV has no gross effect on larval metabolic rate. The respiratory rate of HeCV injected larvae is a linear function of body weight as it is for the control and saline injected larvae in the fourth and early fifth instars. There was a significant correlation between larval weight and larval oxygen consumption in control, saline injected and HeCV injected larvae but not in parasitoid larvae during the time that oxygen consumption was measured. Wounding, i.e. injection, caused a significant reduction in oxygen consumption on the day of the injection. The larvae recovered from this the next day.^ Hemolymph protein concentration in control and saline injected larvae shows a cyclical pattern within a stadium, decreasing during a molt and increasing prior to the next molt. Injection of T. ni larvae with a purified preparation of HeCV causes a significant reduction in hemolymph protein concentration for five days beginning two days after the injection. HeCV injcted larvae do not show the cyclical pattern of hemolymph protein concentration within a stadium which is characteristic of the controls. Electrophoresis of hemolymph proteins through a 6% polyacrylamide gel using a discontinuous buffer system resolved twenty-two protein bands in control and saline injected larvae and fourteen bands of HeCV injected larvae. ^

Subject Area

Entomology

Recommended Citation

KENNEDY, ROBERT MICHAEL, "VIRUS PARTICLES FROM THE REPRODUCTIVE TRACT OF THE FEMALE PARASITOID HYPOSOTER EXIGUAE (VIERECK) (HYMENOPTERA: ICHNEUMONIDAE): PHYSIOLOGICAL EFFECTS ON THE LARVAE OF THE CABBAGE LOOPER, TRICHOPLUSIA NI (HUBNER) (LEPIDOPTERA: NOCTUIDAE)" (1983). ETD Collection for Fordham University. AAI8323536.
http://fordham.bepress.com/dissertations/AAI8323536

Share

COinS