Effect of two prey types on life-history characteristics and predation rate of Geocoris floridanus (Heteroptera: Geocoridae)

Abstract

The predator Geocoris floridanus Blatchley has become more common in row crop systems in Georgia, but its ecology is unknown. We studied selected life-history characteristics of G. floridanus in the laboratory. Two prey treatments were evaluated for nymphs and adults of G. floridanus: 1) eggs of the corn earworm, Helicoverpa zea (Boddie), and (2) young larvae of the beet armyworm, Spodoptera exigua (Hübner). G. floridanus nymphs were reared on the prey, and predator development and prey consumption were monitored; predation rates, longevity, and fecundity of adults were evaluated. Nymphal development times and number of prey consumed by predators fed corn earworm eggs were similar for females and males. Nymphal development of predators fed beet armyworm larvae was prolonged compared with predators reared on corn earworm eggs. Nymphal survival was unaffected by prey type. Nymphs reared on corn earworm eggs required fewer prey to complete nymphal development and produced larger adults. Females fed corn earworm eggs had shorter preoviposition periods, and greater fecundity and longevity than females fed beet armyworms. Females consumed more beet armyworms than corn earworm eggs, but produced fewer eggs per unit prey. Female predators fed beet armyworms while nymphs and switched to corn earworm eggs when adult partially recovered their fecundity, and exhibited life-history characteristics equal to those of females fed corn earworm eggs throughout their lives. Thus, G. floridanus can feed, develop, and reproduce on both prey species, and its performance increases when switched from beet armyworm larvae to corn earworm eggs.