Generation-dependent functional and numerical responses of a naturally fungus-infected colony of Habrobracon hebetor (Hymenoptera: Braconidae) reared on Ephestia kuehniella (Lepidoptera: Pyralidae) in Iran

Authors: BADRAN, FATIMA - TARBIAT MODARES UNIVERSITY; FATHIPOUR, YAGHOUB - TARBIAT MODARES UNIVERSITY; BAGHERI, ABDOOLNABI - TARBIAT MODARES UNIVERSITY; ATTARAN, MOHAMMADREZA - TARBIAT MODARES UNIVERSITY; Reddy, Gadi V.P.

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2020
Publication Date: 12/15/2020
Citation: Badran, F., Fathipour, Y., Bagheri, A., Attaran, M., Reddy, G.V. 2020. Generation-dependent functional and numerical responses of a naturally fungus-infected colony of Habrobracon hebetor (Hymenoptera: Braconidae) reared on Ephestia kuehniella (Lepidoptera: Pyralidae) in Iran. Journal of Economic Entomology. 114:1-10. https://doi.org/10.1093/jee/toaa268.
DOI: https://doi.org/10.1093/jee/toaa268

Interpretive Summary: Large-scale production of natural enemies on alternative or natural hosts or on artificial foods is a common approach in biological control programs that helps to reduce the cost of effective insect pest management. The ectoparasitoid wasp Habrobracon hebetor is a well-known biological control agent in many inundative and inoculative programs due to its high rate of reproduction and efficiency, short generation time, and diverse range of host species. investigate the possible changes that may occur in the behavioral aspects of parasitoid infected naturally with a fungal species. The results indicated that the efficiency of infected wasps varied significantly during mass rearing, in which the first and last generations were the most efficient. In addition to the significant effects of long-term rearing on the performance of parasitoid, fluctuations in the latter could also be due to fungal infections. To this end, a parallel study of infected and non-infected generations would be very useful in terms of the demographic parameters and search behaviors that it might reveal.

Technical Abstract: The functional and numerical responses of Habrobracon hebetor (Say) were assessed over 30 sequential generations (G) on different densities (2, 4, 8, 16, 32, 64, and 128 fifth instar larvae) of the Mediterranean flour moth Ephestia kuehniella (Zeller). Seven tested generations (G2inf, G4inf, G6inf, G8inf, G10inf, G15inf, and G30inf) had already been naturally infected by a fungus species, while only the second generation had the colonies of both infected (G2inf) and uninfected (G2uninf) individuals. All infected generations, as well as the uninfected generation, showed a Type III functional response. A high variation was found in the handling times (Th) of the parasitoid through 30 sequential generations, and G10inf had the longest handling time. The shortest handling time and the maximum estimated attack rate (T/Th) were observed in G2inf. No significant difference in terms of the number of parasitized hosts was found among all infected generations, as well as between G2inf and G2uninf. Although the handling times in G2inf and G2uninf were close to each other, the attack coefficient of G2uninf was more than that of G2inf. The attack coefficient and handling time of infected generations increased from G2inf to G10inf and then decreased in the higher generations. The most plausible parameters of functional response of infected generations were observed in Ginf. A negative relationship between eggs laid and host densities was observed in the infected generations (G2inf, G4inf, G6inf, G8inf, and G10inf). G2uninf and, among infected generations, Ginf were the best generations for practical utilization in inundative release programs.