Life table parameters of the parasitoid Cephalonomia tarsalis (Hymenoptera: Bethylidae) and its host the saw-toothed grain beetle Oryzaephilus surinamensis (Coleoptera: Silvanidae)

Abstract

Biological parameters of the larval parasitoid Cephalonomia tarsalis (Ashmead) (Hymenoptera: Bethylidae) and its host the saw-toothed beetle Oryzapehilus surinamensis (L.) (Coleoptera: Silvanidae) were studied in the laboratory. The duration of the immature period, survival during development, as well as adult longevity and the number of progeny of both insects were recorded. Our data were used for the estimation of several demographic parameters and life table construction of both the host and the parasitoid. The wasp managed to complete its development (egg - adult) in 19.8 days at 25oC, whereas the adult female lived for 24.3 days. The host O. surinamensis demonstrated a longer developmental period (30.5 days) and adult female longevity (103.0 days). Female wasps laid an average of 66.4 eggs throughout their lifetime whereas their beetle hosts laid five times more eggs (313.9). Life table parameters of C. tarsalis were estimated for the first time. The intrinsic rate of natural increase (rm) was 0.124 which was almost double that of its host (0.056). Our results are discussed on the basis of evaluating and improving the performance of C. tarsalis as a biocontrol agent against O. surinamensis in storage facilities. © 2019 Polish Academy of Sciences. All rights reserved.