Habrobracon hebetor (Hym.: Braconidae) is a cosmopolite ectoparasitoid wasp that is widely used as one of the most important biocontrol agents against larval stages of many lepidopteran pests. The success of parasitoids is usually eva‎luated by counting their hosts killed by parasitoids egg laying and the development of its immature stages on or inside the host, which is called reproductive effect. The non-reproductive effects of parasitoids, such as Pseudo-parasitism, paralyzing the host, and changing the host’s behavior and physiology due to the presence of the parasitoid, which can reduce the density of the host’s population, have recently been noticed. The performance of parasitoids by both reproductive and non-reproductive effects is affected by the internal condition of the parasitoid and the conditions of the host. In this research, reproductive and non-reproductive effects of H. hebetor wasp on its host, Ephestia kuehniella (Lep.: Pyralidae) were investigated under different conditions of age, feeding and experience status, and presences of conspecific individuals as well as different density and sizes of the host. Our results showed that the age of the female wasp has a significant effect on the fertility and the number of parasitized larvae, so that the lowest these parameters, 1.20±0.49 and 0.53±0.16, respectively, were seen in 11-day-old female compared to three- and seven-day-old females. The number of paralyzed larvae is not influenced by female’s age. Also, the wasps fed with honey water has significantly more fertility (8.07±0.93) than the wasps without feeding (3.29±0.86) (p˂0.00), but the number of paralyzed larvae and the pattern of female oviposition on the host larvae does not change with female feeding. The measured parameters are not influenced by previous handling host experience of female wasp. The amount of parasitized larvae is not affected by the presence of the conspecific female wasp, but the number of paralyzed larvae and the number of non-consumptive larvae are negatively affected by the presence of the conspecific females, so that the least number of paralyzed larvae (4.42±0.91) and the highest number of non-consumptive larvae (4.08±0.59) is seen in the without conspecific female (p˂0.04). The density of the host caused a significant increase in the number of paralyzed larvae, so that the highest number of paralyzed larvae (24.25±0.64) is seen in the density of 30 host larvae (p˂0.00). Host size has no significant effect on parasitism and other measured parameters. In all the experiments, the weight of the host pupa significantly decreased by the exposed to the parasitoid wasp (p˂0.00). The results of the present study showed that age, diet and presence of conspecific female parasitoid, and density of host larvae affect the reproductive effects of the H. hebetor on its host. Also, non-reproductive effects such as the amount of paralyzed larvae and weight loss of host pupae under the influence of wasp are observed. The results showed that various factors can affect the reproductive and non-reproductive effects of parasitoids on their host, which should be considered in their mass rearing, biological control programs, and efficiency eva‎luation in the field.

نفيسه پورجواد

جهانگير خواجه علي، امير حسين مهدوي