Journal of Plant Protection Research (2015) 55, 142-150

Fater Mohamad, Mohammed Mansour and Ali Ramadan (2015)
Effects of biological and environmental factors on sex ratio in Ascogaster quadridentata Wesmael (Hymenoptera: Braconidae), a parasitoid of Cydia pomonella L. (Torticidae)
Journal of Plant Protection Research 55 (2), 142-150
Abstract: The sex ratio in the natural population of most Hymenopteran parasitoids is 1 : 1. Females of these parasitoids, however, can regulate the sex of their offspring in response to environmental and biological factors. Under certain circumstances, this may lead to an overproduction of males, which can result in a very negative impact on any control program using these parasitoids. For these reasons, understanding the effect of these factors is very important. In this study, five biological and environmental factors known to affect sex ratio in parasitic Hymenoptera were investigated for Ascogaster quadridentata Wesmael, a parasitoid of Cydia pomonella L. Results showed that food, ambient temperature, and parasitoid age had significant effects on the sex ratio of the offspring of Hymenopteran parasitoids. The percentage of females decreased with lack of food, parasitoid age (when it became 10-days-old or older), and at low (15°C) and high (35°C) temperatures. The effect of host age and density, however, was not significant.
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Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cydia pomonella	Apple (Malus)	Syria
Ascogaster quadridentatus (parasitoid)	Cydia pomonella	Apple (Malus)	Syria