Lifetime egg maturation by host-deprived Venturia canescens

Area of Science:

• Entomology
• Insect reproductive biology
• Parasitoid wasps

Background:

• Endoparasitoid wasps play crucial roles in biological control.
• Understanding reproductive strategies in parasitoids is key to optimizing their use.
• Venturia canescens is a model organism for studying parasitoid behavior.

Purpose of the Study:

• To investigate egg maturation and deposition in Venturia canescens under host deprivation.
• To determine the factors influencing egg maturation rates and egg discarding behavior.
• To elucidate the physiological mechanisms regulating egg production in parasitoids.

Main Methods:

• Observation of egg deposition in host-deprived female Venturia canescens.
• Monitoring of egg maturation rates over extended periods.
• Experimental manipulation of the ovipositor and auxiliary valvulae to assess their impact on egg maturation.

Main Results:

• Female V. canescens deposited eggs without hosts, with continuous maturation observed.
• Egg maturation continued at a rate of approximately 5.8% daily under host deprivation.
• Ovipositor damage reduced egg maturation, while auxiliary valvulae damage had no effect.
• Host access increased the rate of additional egg maturation.

Conclusions:

• Egg maturation rate in V. canescens is regulated by fat body precursor synthesis, influenced by ovipositor feedback.
• Egg discarding is an involuntary process driven by unidirectional oviduct movement and ongoing egg maturation.
• The findings provide insights into the reproductive physiology of endoparasitoid wasps.