Sub‐lethal effects of Metarhizium anisopliae on the life table parameters of the predatory coccinellid Menochilus sexmaculatus Fabricius

Abstract

Entomopathogenic fungi Metarhizium anisopliae (Metschnikoff) (Hypocerales: Claviciptaceae), as a microbial control agent, and the predator Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae) have been considered to regulate insect pest populations. The experiments were conducted on adults of coccinellid that were sprayed with conidial suspensions at a concentration of 1.11 × 104 conidia ml−1. This study reports on some laboratory experiments investigating the effects of the isolate of M. anisopliae on the biological and life history traits of Men. sexmaculatus by using the paired bootstrap procedure. Males progeny from individuals exposed to the fungus had a significantly different developmental time, but there was no difference between females when compared to the control group. However, fecundity did not differ in the treated and control groups (391 and 408.39 eggs respectively); the sex ratio (%female/total) ranged from 62% to 63%. The intrinsic rate of increase (r), finite rate of increase (λ) and net reproductive rate (R0) had no significant differences in the progeny of the fungal‐treated and untreated groups. Consequently, M. anisopliae had low effects in the sub‐lethal concentration on the biological parameters and fecundity of Men. sexmaculatus. The results, thus, suggest that M. anisopliae may be compatible with Men. sexmaculatus in an IPM programme.