Factors affecting cannibalism by Mallada basalis

Abstract

ABSTRACTCannibalism within arthropod populations is widespread and can regulate populations. The relationships between larval cannibalism of the biological control agent Mallada basalis (Neuroptera: Chrysopidae) and different factors, including feeding density, starvation time, food type and amount, temperature, humidity, and photoperiod, were studied. As feeding density, temperature, or photoperiod increased, the frequency of larval cannibalism increased, whereas it declined with increasing prey availability. Total cannibalism mortality was greatest when food (the diet included 0.03 g of Corcyra cephalonica eggs, Lipaphis erysimi nymphs, or an artificial diet) was insufficient; it was also high at 35°C. Total cannibalism mortality was lowest when the feeding density was 2 larvae/petri dish. Duration of starvation and humidity did not affect total cannibalism mortality. Results indicated that feeding density, food amount, temperature, and photoperiod were the four main factors that affected cannibalism in M. basalis. These results provide critical new information for the mass rearing of M. basalis.