The Effect of Experience and Age on Foraging Behavior of a Thelytokous Parasitoid, Lysiphlebus fabarum (Marshall) on Aphis fabae Scopoli

Document Type : Research Article


Shahid Chamran University of Ahvaz


Parasitic insects face many decisions when foraging for host, some for example frequently have to make decisions with regard to staying in or leaving their current patch. In this study, we investigated how the foraging and oviposition behavior of Lysiphlebus fabarum is influenced by (1) a female’s previous experience of encountering aphids host and (2) age of female parasitoids. To test this, I released individual L. fabarum females onto bean leaf disks with 15 second-third instar of A. fabae in the laboratory and made continuous observations, and then females’ proportional time allocation to various activities and oviposition decisions were measured. Pre-trial exposure of females to aphids for a period of 24 h, as opposed to one h, showed females that experienced more host deprivation remained more than twice as long in arenas as those from a 24 h exposure to aphids. Furthermore, all measured distinct behavior was higher for less experience females. Because of the large effect of treatment on patch residence time, the incidence or duration of various behaviors was expressed as a fraction of patch residence time and then re-analyzed. Data showed no difference in the incidence and duration of all behaviors. In the second experiment, Five days old females remained more than three times as long in arenas as did one d-old females and scored higher values for the incidence and duration of almost all behaviors. However, when values were expressed as fractions of patch time there were no significant differences between young and old females, suggesting that age like experience, had no effect on proportional time allocation to various behaviors during patch exploitation.

Key words: Patch residence time, Behavior allocation, Aphid defense, Thelytoky