Impact of inbreeding on performance of the predator Podisus maculiventris

Effects of inbreeding on the development and reproduction of the predatory pentatomid Podisus maculiventris were assessed throughout 30 generations fo llowing introduction in the laboratory. Developmental and reproductive fitn ess of two mildly inbred lines did not differ dramatically from that of a r eference population. In most generations, egg weight, egg hatch and develop mental rate of nymphs were greater in the reference strain than in both inb red strains, but fecundity and longevity did not differ among strains. In t he 30th generation, fecundity of all strains had dropped to about half of t hat observed in the 15th generation, which was presumably related to non-ge netic factors. There were consistent differences among strains for adult bo dy weight and size, indicating heritable variation. A positive relationship between weight at day 14 and humeral width of P. maculiventris females was found, but neither of these parameters was associated with total fecundity . In the 30th generation, predators from both inbred lines had generally si milar predation capacities to those from the reference population. No signi ficant relationship could be detected between body weights and predation ra tes of either nymphs or adults. The use of inbreeding to minimize selective adaptation during rearing or to select for favourable traits in P. maculiv entris is discussed.