Biological features ofThrips palmi (Thysanoptera: Thripidae) and consumption capacity of a natural enemy under laboratory conditions

Abstract

Thrips palmi is an exotic pest registered for Colombia since 1997. This research was made attempting to acquire a best knowledge about insect 's biology and ecology, especially his lifecycle. lt was also wanted to account for the consumption capability of Chrysoperla carnea (Neuroptera: Chrysopidae) on T. palmi. The environmental conditions were a medium temperature of 26ºC (d.s. 2.19) and a medium relative humidity of 53, 06% (d.s.5, 54). The experimental unit was an uncolored photographic plastic that can cut by the middle. Adults of T. palmi were collected at the field and his progeny was used for the evaluation of in nature's lifetime and adult's longevity. The predatory capability of e.carnea was evaluated at 24 hours of predator-prey interaction at levels of 10, 20 and 30 preys and O, 1,2,3 predators. The medium times in days for immatures feed on beans (Phaseolus vulgaris) was 2, J 4 for the first nymphal instar (n l ): 1,56 for the second (n2); 1,05 for prepupae (pp) and 2,2 for pupae (p). The live hope (ex) for n 1 was 1,99; for n2: 1,83; for pp: 1, 71, for p: 0,91. The sex ratio was 1:3,5 (male/female). Chrysoperla carnea had a medium consumption of 14,4 trips nymphs in 24 hours. The variance analysis reveals that the statistically significative effect obtained (F: 23, 71; p: 0,0001) was related to different predator densities and not to the different prey densities. The plots that included predator had significative differences with plots with no predator. At present prey level, there were no significant differences within two or three predators. Despite the cryptids may have a higher consumption of thrips at high-density levels (3 predators), the individual effectiveness is reduced by interference and cannibalism (in this case related to laboratory conditions).