Study of Feeding Preference and the Effect of Some Hosts of Aphid on Some Biological Aspect of the Coccinella Septempunctata (Coleoptera: Coccinellidae)

Abstract

The current study included a food preference test for C.septempunctata in a modified McDonald's way in
preferring a type of aphid than the other, as well as to know the effect of the host species of prey in
attracting predators. In which the type of aphid had been studied and they are Schizaphisgraminum,
Aphis Nerii and thrioaphistrifolii. The results show that adult predators are attracted towards S.
graminum followed by A. nerii and T. trifolii. When the adults were exposed to plants without aphid,
they showed an attraction towards the Triticumspelta, followed by Nerium oleander and Medicago sativa
plants successively. The study also included the testing of aphid species at different stages of life for the
mentioned type. The results of the study showed that the growth rate of predator larvae differed
according to the insect host. The longest duration of the larval stage was (16091) day when feeding on S.
graminum and the shortest (12.01) day when feeding on T. trifolii. As for the pupae role, the longest
duration was (5.85) day when feeding on A.nerii insect. As for adults, the duration of pre-laying eggs, the
number of eggs, incubation and the proportion of hatching differed depending on the host insect. The
highest pre-egg laying time was (7.95) day when feeding on Nerium oleander aphid and the least (4.77)
day in feeding on T. trifolii and the highest rate of eggs lying was (800.30) and the lowest (386.00) in
feeding on S. graminum. The highest egg incubation period reached (4.00) day in feeding on A. Nerii and
the lowest (2.00) day in feeding on T. trifolii. The highest percentage of egg hatch is (88.82) in feeding on
S. graminum and the lowest is (60.33) % in feeding on A. nerii
Keywords: Hosts, Biological aspect, Coccinella Septempunctata.