Influencia do fotoperiodo no desenvolvimento e na reproducao de Chrysoperla externa (hagen) (Neuroptera: Chrysopidae) | Influence of the photoperiod on development and reproduction of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)
2003
Macedo, L.P.M. | Souza, B. | Carvalho, C.F. | Ecole, C.C.
To know the influence of abiotic factors on bioecology of Chrysopidae, especially those from South America, is important in order to use these predators in biological control programs. This research was carried out with the objective of studying, in laboratory conditions, the influence of the photoperiods 8L:16D, 10L:14D, 12L:12D, 14L:10D and 16L:8D on biological aspects of Chrysoperla externa (Hagen), with light intensity near to 1,500 lux, temperature of 25 +/- 2 degrees C and 70 +/- 10% RH. The quantity of light did not affect the duration of the embryonic period, the number, duration and viability of instars, as well as adult mortality and pre-oviposition period. However, duration time of the larvae, pre-pupae and pupae decreased with the increase of the photofase. The eggs survival was smaller at 10h (85.6%) and 14h (77.8%) light. An inverse relationship was observed between photofase duration and fecundity, thus obtaining 778.3 eggs per female maintained at 8h light, and 233.0 eggs per female at 16h light. No morphological, physiological or behavioural changes were observed that could characterize a diapause symptom in C. externa population. These results help to improve the techniques for rearing the species in laboratory conditions.
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