Feeding Ecology of Pest Mole Crickets (Orthoptera: Gryllotalpidae: Scapteriscus spp.) and Associated Damage to Turfgrass

Abstract

Two omnivorous species of mole crickets (Orthoptera: Gryllotalpidae), Scapteriscus vicinus Scudder and S. borellii Giglio-Tos, are introduced subterranean pests that cause damage to turfgrass by feeding and tunneling in the southeastern United States. Unlike strict herbivores, the impact of omnivorous pests on host plants can vary according to the availability of plant and animal prey. After a series of greenhouse experiments investigating the influence of earthworm (Eisenia fetida Savigny) prey on hybrid bermudagrass by adult S. vicinus and S. borellii, it was shown that alternative prey, when present, may result in a negative impact on turfgrass roots from foraging omnivorous mole crickets. In laboratory experiments, the feeding preference of both mole cricket species was determined using choice and no-choice tests. In choice tests, S. borellii preferred an animal diet and plant diets were preferred by S. vicinus supporting the previous studies on gut contents. Additionally, further investigation about the impact of diet on survival and nymphal development provided insight into the relative benefits of each dietary choice on these omnivores. Overall, S. borellii provisioned with animal diet had less mortality, greater body mass, and faster development compared to the ones fed on plant diet. Even though S. vicinus is primarily a herbivorous species, nymphs fed on animal diet gained more weight and developed faster than the ones fed on plants. This work suggests that S. vicinus and S. borellii have the capability of nutrient regulation and adaptability on various diets, and that an animal diet benefits both species in terms of survival and nymphal development.