Progeny production and adult longevity of the mealybug parasitoidsAnagyrus pseudococci, Leptomastix dactylopii, andLeptomastidea abnormis [Hym.: Encyrtidae] in relation to temperature

Abstract

Progeny production increased and adult longevity decreased with rising temperature within the range 18 *C to 30 *C for the 3 mealybug parasitoids Anagyrus pseudococci (Girault), Leptomastix dactylopii Howard and Leptomastidea abnormis (Girault). The Weibull distribution gave a good fit to survival curves for the 3 parasitoids and statistical comparison of Weibull b and c parameters at different temperatures allowed changes in the scale and shape of the curves to be detected, In general, ~ lived longer than ~' for all 3 species, except at high temperature.Female L. abnormis attained their maximum progeny production at 24 *C and maintained this level up to 34 *C. They lived longer than the other 2 parasitoid species at 30 *C and showed a type I survival curve throughout the range of temperatures examined. A. pseudococci and L. daetylopii both required high temperatures (30 *C) to attain their maximal progeny production, but were short-lived at this temperature. At 30 *C the survival curves of both ff and ~ A.pseudococci tended towards type II, with a larger proportion of the population dying within the first few days. L. dactylopii lived longest at 26 *C, with ~ showing a type I survival curve at all temperatures and ~' survival curves changing from type I to type II at 30 *C. The implications of these findings for the population dynamics of the different parasitoids are briefly discussed.

Life table parameters of the pseudococcid predators Nephus includens and Nephus bisignatus (Coleoptera: Coccinelidae)

“…4 and the values of the Weibull parameters in Table 3. In both species it is a type I survival curve, as parameter c is >1 (Tingle & Copland, 1989;Wang et al, 2000). Using mathematical models to describe the reproductive capacity and survival enables one to compare data with similar average values, which differ in their temporal distribution (Tingle & Copland, 1989).…”

“…The Weibull frequency distribution was used to describe the age specific survival of female adults. The probability that an individual lives at least to time t was calculated following Deevey (1947), Pinder et al (1978), Tingle & Copland (1989) and Wang et al (2000):…”

Egg laying and host stage preference at constant temperatures inEncarsia tricolor [Hym.: Aphelinidae]

“…increased with temperature from 10 to 28 *C, reaching a maximum of 123 eggs per female at 28 *C, and decreased sharply from 28 to 32 ~ Such a relationship has been widely reported in insects (Ratte, 1985 ;Tingle & Copland, 1989). The function developed by Hilbert & Logan (1983) As the E. tricolor females were kept at 24 *C for 16 hours each day, the reduction in the fecundity observed at low temperatures may be caused by a reduction in the searching capacity of the female, as reported in Spalangia endius Walker (Ables & Sbepard, 1976) more than by a decrease in oocyte maturation.…”

Effects and interactions of temperature, host deprivation and adult feeding on the longevity of the parasitoid Venturia canescens (Hymenoptera: Ichneumonidae)

“…The longer a male wasp lives the more females it can inseminate, while the longer a female can live the more eggs it can lay (Tingle & Copland, 1989;Jervis & Copland, 1996;Jervis et al, 1996). Longevity is a variable species specific characteristic, which is influenced by a range of biotic (host, body size, mating, adult feeding, etc.)…”