ENTOMOLOGY F.S. Ramalho et al. (2008) Phytoparasitica 36(1):30-37 Reproductive Strategy of Podisus nigrispinus Females under Different Feeding Intervals ES. Ramalho, 1'* J. Mezzomo, 1 W.E Lemos, 1 C.M. Bandeira, 1 J.B. Malaquia, ~ J.P.S. Silva, 1 G.L.D. Leite 2 and J.C. Zanuncio 3 An attempt was made to quantify the influence of prey scarcity on longevity and on the reproductive variables of females of the predator Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae). The predators received prey (Alabama argillacea) of different sizes, viz., 50 mg (small prey) or 220 mg (large prey), for a period of 24 h, daily or every 2, 4, 8 or 16 days. In an additional trial, the predators were provided only with water or kept without food, in which latter condition they lived a significantly shorter time. Individuals that received large prey in excess (every day) and at 16-day intervals lived significantly less, while the longevity of those that fed on small prey did not differ significantly between feeding intervals. Predators that fed less frequently laid fewer eggs, with increased intervals between clutches. The results were more marked in females fed on small prey; however, evidence of trade-off between reproduction and survival was detected only in predators that received large prey. The results suggest a type of trade-off, where longevity is maintained at the expense of reproduction. This strategy can contribute to the establishment and survival of P. nigrispinus in an environment of fluctuating food supply. KEY WORDS: Predators; food scarcity; life history; biological control. INTRODUCTION The representatives of the genus Podisus are generalist predators, which have been found in many parts of the American continent, feeding mainly on immature lepidopterans and coleopterans (7,8). In the cotton agroecosystem the species Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) has been able to kill, efficiently, the major defoliating pest in Brazil, the cotton leafworm (Alabama argillacea Hiibner) (18). Alimentary limitation affects several parameters in the life history of arthropods, such as development rate (25), body size (14,21), survival (35), fecundity (14,25) and diapause (1). Besides, food scarcity may promote limited growth in the population (9) or increase inter-species competition (19,35). However, there is no unanimity among the researchers about the possibility of food scarcity for predators being a common phenomenon in nature. According to some researchers, the intensity of natural alimentary limitation may vary in time and/or space (25,36) and, in some cases, predators are not subjected to it (4,13). An important attribute of predators, as agents for biological control, is their ability to establish populations and to persist in a specific ecosystem. Consequently, efficient Received March 15, 2007; accepted Sept. 16, 2007; http://www.phytoparasitica.orgposting Dec. 11, 2007. 1 Unidade de Controle Biol6gico(UCB)/EmbrapaAlgodfio, 58107-720, CampinaGrande, State of Paral'ba, Brazil. *Corresponding author [e-mail: framalho@pesquisador.cnpq.br]. 2UFMG/Nticleo de Cirncia agr'Zrias,Montes Claros, State of Minas Gerals, Brazil [e-mail: gldleite@ufmg.br]. 3Depto. de Biologia Animal, Universidade Federal de Viqosa, 36571-000, Viqosa, State of Minas Gerals, Brazil [e-mall: zanuncio@ ufv.br]. 30 ES. Ramalho et al.