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Title: DEVELOPMENT, LONGEVITY AND FECUNDITY OF CHELONUS SP. NR. CURVIMACULATUS (HYMENOPTERA: BRACONIDAE), AND EGG-LARVAL PARASITOID OF PECTINOPHORA GOSSYPIELLA SAUNDERS (LEPIDOPTERA: GELECHIIDAE)

Author
item HENTZ, MATTHEW - UNIVERSITY OF ARIZONA
item ELLSWORTH, PETER - UNIVERSITY OF ARIZONA
item Naranjo, Steven
item WATSON, THEO - UNIVERSITY OF ARIZONA

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: The pink bollworm is a serious pest of cotton in the southwestern United States. Pesticides are currently the main method of control and more biologically-based methods are urgently needed. Several species of exotic insect parasites have been introduced in CA and AZ for biological control; however, none have established or had any effect on pest suppression. Most of these parasites were released with little knowledge of their biology an potential for control. Chelonus sp. nr. curvimaculatus is an egg-larval parasitoid of pink bollworm that was introduced in the 1970s. This study investigates developmental and reproductive rates of this parasite in relation to temperature and photoperiod. The rate of development from egg to adult increased linearly from 20 to 32C, and declined again at 35C. Females developed slower at lower temperatures, but both sexes were similar at higher temperatures. Thermal constants for female and male from egg to adult was 366 and 353 above a base temperature of 12.95C and 12.47C, respectively. Longevity of adults declined with temperature and was highest at 20C (16.5-20d), although at 35C both sexes survived about 6.5 d. Lifetime fecundity was highest at 25C (420 offspring) and lowest at 35C (67). Superparasitism varied with temperature and was greatest at 25 & 30C (55%). Net reproductive rates were highest at 20C (103.37) and lowest at 35C (32.79). Overall, photoperiod had little effect on parasite development or fecundity.

Technical Abstract: Developmental time, adult longevity, and fecundity of Chelonus sp. nr. curvimaculatus, an egg-larval parasitoid of Pectinophora gossypiella, were studied in the laboratory under five constant temperatures and three photoperiods. Parasitoid development, from egg to adult, was slower for females (53.6 d, 20C) than for males (49.5 d, 20C) at lower temperatures, but both sexes developed at similar rates at higher temperatures (19.9, 18.8, respectively, 35C). The thermal constant for female and male from egg to adult was 366 and 353 above a base temperature of 12.95C and 12.47C, respectively. Adult male and female parasitoids lived longest at 20C (16.6- 20 d), and at 35C both lived about 6.5 d. True and realized lifetime fecundity was highest at 25C (1034 and 420 offspring, respectively) and lowest at 35C (119 and 67, respectively). The percentage of superparasitized host eggs was greatest at 25 and 30C (55%), and lowest at 35C (29%). Net reproductive rates were variable in all conditions. Based o the realized fecundity, Ro was highest at 20C (103.37) and lowest at 35C (32.79). Temperature and the age of the parasitoid had the greatest influence on fecundity. Photoperiod played a minor role in influencing developmental rate, but not adult longevity or fecundity of C. sp. nr. curvimaculatus.