Mutual interference of Telenomus busseolae Gahan, an egg parasitoid of sugarcane stem borers Sesamia spp.

Subject Areas : entomology and othea arthropods

M. Esfandiari ¹ (Department of Plant Protection, College of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran)
E. Soleyman-Nejadian ² (Department of Plant Protection, College of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran)

Received: 2011-01-09 Accepted : 2011-12-14 Published : 2012-11-21

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Abstract :

When females encounter either an already parasitized host or a parasitoid mark on the substratum, they move away from the area. The present study investigates the mutual interference of T. busseolaeon Sesamia spp. eggs, at 29±1°C, 65±5% and 16:8 (L:D) photoperiod. In this experiment the constant density of 150 fresh host eggs were allocated for each wasp density. Densities of 1, 2, 4, 6 and 8 female wasps (with maximum age of 24hours) were chosen randomly from the wasp rearing colony from the Sugarcane Research Center of Khuzestan, placed separately in vials and fed with 10% sugar solution. The wasps removed after 24 hours. The relationship between the logarithm of the densities of searching parasitoids and the logarithm of searching efficiency for each wasp was linear ) F=619.5, r2=0.995, P=0.001). The coefficient of the regression line (m) was -1.4063. The negative value of (m) indicates that the mutual interference acts as reverse density-dependence factor. With parasitoid density increasing from 1 to 8, the per capita parasitism and per capita searching efficiency decreased from 135 to 12.4 and 2.40 to 0.14, respectively. These studies can lead to an improvement in mass rearing techniques at insectariums and rate of natural enemies release in green houses.