Entomophaga (1996) 41, 217-224

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M. Kenis (1996)
Factors affecting sex ratio in rearing of Coeloides sordidator (Hym.: Braconidae)
Entomophaga 41 (2), 217-224
Abstract: Five factors known to affect the sex ratio (% of males) in parasitic Hymenoptera were investigated for Coeloides sordidator a parasitoid of Pissodes 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 from Pissodes castaneus was significantly more male-biased than the strain from P. validirostris, which corroborates previous observations made on field populations.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Marc Kenis

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
rearing/culturing/mass production

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Pissodes castaneus
Pissodes validirostris
Coeloides sordidator (parasitoid) Pissodes castaneus
Coeloides sordidator (parasitoid) Pissodes validirostris