caa a22 4500 477073565 CHVBK 20180405111433.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF02764247 doi (NATIONALLICENCE)springer-10.1007/BF02764247 Kenis M. International Institute of Biological Control, European Station, 1 chemin des Grillons, 2800, Delémont, Switzerland aut Factors affecting sex ratio in rearing of Coeloides sordidator (Hym.: Braconidae) [Elektronische Daten] [M. Kenis] Facteurs influençant la sex-ratio dans un élevage de Coeloides sordidator (Hymenoptera: Braconidae) Five factors known to affect the sex ratio (% of males) in parasitic Hymenoptera were investigated forCoeloides sordidator, a parasitoid ofPissodes weevils. The host age, the age of ovipositing females, and the host of origin had a significant impact on the sex ratio of offspring. In contrast, the number of ovipositing females had an insignificant effect on sex ratio whereas the effect of host density could not be clearly defined. The sex ratio decreased with host age, probably because, like many other hymenopteran parasitoids, females tend to lay male eggs on small hosts and female eggs on larger hosts in order to maximize the size and fitness of their female offspring. The sex ratio also varied with the age of the mother, younger females laying more male eggs and older females more female eggs. The host of origin also had an influence on sex ratio. The strain fromPissodes castaneus was significantly more male-biased than the strain fromP. validirostris, which corroborates previous observations made on field populations Lavoisier Abonnements, 1996 biological control nationallicence parasitoids nationallicence Pissodes nationallicence sex ratio nationallicence Entomophaga Springer Netherlands 41/2(1996-06-01), 217-224 0013-8959 41:2<217 1996 41 10526 https://doi.org/10.1007/BF02764247 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02764247 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Kenis M. International Institute of Biological Control, European Station, 1 chemin des Grillons, 2800, Delémont, Switzerland aut NATIONALLICENCE 773 0- Entomophaga Springer Netherlands 41/2(1996-06-01), 217-224 0013-8959 41:2<217 1996 41 10526 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer