Biology of Mallochia pyralidis (Hymenoptera: Ichneumonidae), an Ectoparasite of Eoreuma loftini (Lepidoptera: Pyralidae) from Mexico

Abstract

Development, survivorship, and reproduction of the ichneumonid ectoparasite Mallochia pyralidis Wharton with the pyralid Eoreuma loftini (Dyar) as a host were studied at constant 26°C. Mean developmental time from egg to adult was 17.9 d for males and 18.9 d for females. Egg, larval (four instars), and pupal developmental times averaged 2.0, 7.5, and 8.8 d, respectively. Seventy-three percent of the individuals survived from egg to adulthood with mortality concentrated in the egg and first instar. Females deposited an average of 88.5 eggs throughout their life span with 10 hosts provided daily. Female longevity averaged 47.1 d with 50% of the eggs laid during the first 11 d of age and 90% during the first 23 d. An average of two eggs (range, 1–15) were laid per host, but only one parasite per host completed development, because of cannibalism by early instars. Sex ratio was skewed towards males (>70%), probably an artifact of rearing conditions. Unmated females produced only male progeny. General descriptions of M. pyralidis life stages are provided.