| Delphastus catalinae (Horn)(Coleoptera, Cocciellidae)is an important predator of whitefliesand is widely applied at abroad in recent years. In this work, the artificial diets of adultD.catalinae were studied, in order to provide theoretical basis for mass rearing of D.catalinae. Themain results obtained were as follows:The Tenebrio molitor pupae, Bactrocera dorsalis mature larvae and Corcyra cephalonicaegg were respectively uesed as the main ingredient of artificial diets. The T.molitor pupae andB.dorsalis mature larvae were processed into3forms: homogenate, full-fat, and defatted. So therewere7kinds of artificial diets used in the experiments, which were homogenate of T.molitorpupae (Hy), full-fat of T.molitor pupae (Hq), defatted of T.molitor pupae (Ht), homogenate ofB.dorsalis mature larvae (Jq), full-fat of B.dorsalis mature larvae (Jq), defatted of B.dorsalismature larvae (Jt) and C.cephalonica egg (M). The effect of the artificial diets was evaluated bythe longevity and mortality of D.catalinae fed. The results showed that D.catalinae feeding onC.cephalonica eggs could develop longest for93days, which was close to90days of feeding onwhiteflies. But there were higher mortality rate within the first six days. Mortality rate ofD.catalinae with different artificial diets in descending order were Ht (56%)=Hy (56%)>Jq(40%)>Hq (32%)=Jt (32%)=Jy (32%)>M (28%). The average longevities of D.catalinae withdifferent artificial diets in descending order were CK2(69.80d)＞M (35.44d)＞Jt (22.12d)＞Ht(20.50d)＞Jq (18.10d)＞Jy (17.02d)＞Hq (16.68d)＞Hy (14.40d)＞CK1(2.43d). However, nooviposition presented. The effect of the defatted powder of T.molitor pupae was better, comparedwith the homogenate and full-fat powder of T.molitor pupae. The B.dorsalis mature larvae had thesame effect.The predatory behaviors of D.catalinae with artificial diets were observed by a camera todetermine the difference on behaviors aiming to further improve artificial diets. The resultsshowed that, compared with the behaviors of preying whiteflies, the feeding time of D.catalinaewith artificial diets was prolonged in one feeding process, but the number of feeding werereduced in1hour. The feeding time of D.catalinae with different artificial diets in descendingorder was M (3228.29s)> Jt (1714.00s)> Ht (1235.90s)> CK (863.35s). The feeding number ofD.catalinae with different artificial diets in descending order was CK (3.42)> Jt (0.65)> Ht(0.54)> M (0.46). In order to improve the feeding effect, a mixture of sugar with olive oil andthe plant leaf serosity with whitefly were added into artificial diets. The results showed that themixture of sugar with olive oil added into artificial diets had no significant promoting effect, buthad some promoting effect on C.cephalonica eggs. Predation functional responses were made35days after D.catalinaeae fed on artificial diets,to determine the effect of artificial diets on the behavior of preying whiteflies of D.catalinae. Theinvestigation showed that the predation functional responses of D.catalinae fed with artificial dietsall corresponded with Holling Ⅱ model, but the value of a/Th（the ratio of attack rate to handlingtime）in D.catalinae fed with artificial diets was lower than those fed with whitefly. The values ofa/Th of D.catalinae fed with different artificial diets in descending order were M (1.5723)> CK(1.3387)> Ht (1.2469)>Jt (1.169).The feeding time of artificial diet had some effect on the reproduction of D.catalinae.D.catalinae were fed on whitefly15days,25days,35days respectively after having been fed onartificial diets. Once changed to feed on whitefly, it can resume to lay eggs within1-4days. Theoviposition period of D.catalinae with artificial diets was prolonged, compared with theD.catalinae preying on whiteflies, and the egg production of D.catalinae with artificial diets wasreduced. D.catalinae with artificial diets had a shorter oviposition period and a lower fecunditywith the increasing days of feeding on artificial diet. Under the same days of feeding on differentartificial diets, the fecundity of D.catalinae feeding on the egg of C.cephalonica was biggest, andthe oviposition periods of D.catalinae in descending order were M> Ht> CK>Jt. |
