Bilan nutritionnel au cours du développement de l'ectoparasite grégaire Dinarmus vagabundus et du solitaire Dinarmus basalis

Abstract

Mots clds: ectoparasite gr6gaire, ectoparasite solitaire, quantit6 de nourriture assimil6e, biomasse 61abor6e Key words: gregarious ectoparasite, solitary ectoparasite, quantity of assimilated food, biomass produced R~sum~ Nos m6thodes exp6rimentales permettent l'isolement d'une larve de sexe d6termin6 par h6te de l'ectoparasite gr6gaire Dinarmus vagabundus et du solaitire D. basalis. Des h6tes porteurs de 3/t 8 larves par h6te de D. vagabundus sont aussi isol6s. Dans ces conditions la quantit6 de nourriture disponible est la mSme pour toutes les densit6s larvaires 6tudi6es.Les larves 9 9 61ev6es en solitaire des deux esp6ces assimilent une quantit6 de nourriture significativement sup6rieure ~ celle assimil6e par les o" ~. Ceci conduit h des adultes 9 9 de poids moyen sup6rieur ~ celui des o" cy. Le poids moyen des cy cy et des 9 9 de D. vagabundus diminue significativement aux fortes densit6s larvaires. Uintensit6 de la liaison entre la quantit6 de nourriture assimil6e et la biomasse produite s'affaiblit au fur et ~ mesure que la densit6 larvaire par h6te augmente.Les 9 9 de D. vagabundus de poids moyen (0,42 mg) engendrent deux fois et demi plus de descendants que les 9 9 lilliputiennes (0,20 mg) 6merg6es d'h6tes/l forte densit6 larvaire. Celles de D. basalis (0,65 g) sont moins prolifiques que les 9 9 de D. vagabundus.

Parasitism of the grasshopper Melanoplus sanguinipes by a sarcophagid fly, Blaesoxipha atlanis: influence of solitary and gregarious development on host and parasitoid

“…Gregarious development incurred a fitness cost due to the positive correlation between body size and fecundity in females (Figures 1 and 2) and, possibly also, in males. A reduction in body size and fecundity as a result of competition between gregarious larvae is a common phenomenon in parasitic sarcophagids (Coupland & Baker, 1994) and tachinids (King et al, 1976;Grenier, 1981), non-parasitic sarcophagids (Baxter & Morrison, 1983;So & Dudgeon, 1989;Tanaka et al, 1990), and hymenopteran parasitoids (Rojas-Rousse et al, 1988;Taylor, 1988;Reitz & Adler, 1995).…”

Reproductive strategy of Dinarmus vagabundus Timb. (Hym., Pteromalidae): real sex ratio, sequence of emitting diploid and haploid eggs and effects of inbreeding on progeny

“…The hosts were then loaded with a fifth newborn male larva taken with fine forceps from a host parasitized by a virgin female and with a newborn female larva taken from a group of hosts parasitized by fertilized females. The size of newborn larvae was used to determine sex, since the sexual dimorphism of adult size can be detected as early as the newborn larval stage (ROJAS-ROUSE et al 1988). Larval sex was confirmed at nymphal instar, since experimental error remained possible.…”