Dietary choices and their implication for survival and development of omnivorous mole crickets (Orthoptera: Gryllotalpidae)

Abstract

Omnivory is a common feeding strategy in terrestrial arthropods, and omnivores that partake of a mixed diet often gain developmental and reproductive advantages. We determined the palatability and preference of plant and animal foods for two omnivorous mole crickets, Scapteriscus vicinus Scudder and Scapteriscus borellii Giglio-Tos. Adults of both species fed more readily on carrots than bermudagrass blades, rhizomes, and roots. When given a choice, S. vicinus preferentially fed on carrots (plant diet) whereas S. borellii preferred mealworms (animal diet). Nymphs of both species were reared on animal, plant, or mixed (plant–animal rotation) diets. S. borellii fed mealworms developed faster, with greater body mass and survival, and a longer pronotal length compared to individuals fed only carrots. Nymphs of S. vicinus, however, performed slightly better when fed mealworms, and poorer when given a mixed diet. Omnivory among Scapteriscus mole crickets may be a beneficial adaptation for insects in low nitrogen, grassland environments. This work suggests that these two species respond differently to plant and animal diets. S. borellii has a survival and developmental advantage by ingesting animal tissue. Diet will influence the age distribution of field populations, and this may influence interactions with their grass host and natural enemies.