BEMISIA-ARGENTIFOLII (HOMOPTERA, ALEYRODIDAE) AND MACROSIPHUM-EUPHORBIA (HOMOPTERA, APHIDIDAE) AS PREY FOR 2 SPECIES OF CHRYSOPIDAE

The suitability of the whitefly Bemisia argentifolii Bellows & Perring and the potato aphid, Macrosiphum euphorbiae (Thomas), as prey for 2 indigenous species of Chrysopidae, Chrysoperla rufilabris (Burmeister) and Ceraeochrysa cubana (Hagen), was examined. The developmental time and percentage mortality were compared for each prey separately and m ixed. Prey preference was also tested for each predator using 2 prefer ence models as well as a paired t-test. The developmental period for C rufilabris was shortest on a mixed diet of aphids and whiteflies, sug gesting that the nutritional quality of each prey alone was inferior t o that of the combined prey. Development of C, cubana was slowest and mortality was greatest on the aphid diet. Both species of chrysopids w ere able to complete development on immature life stages of the whitef ly alone. Both species consumed greater numbers of whiteflies than aph ids; however, the consumption of aphids increased with each new instar . This trend indicates that prey selection was strongly influenced by increases in body size. The results of the paired t-test and probabili ty model, coupled with the developmental responses in feeding trials, lead us to conclude that C cubana exhibited a preference beyond that w hich was associated with body size for B. argentifobii over M. euphorb iae, whereas C, rufilabris demonstrated little or no such preference.