Aphid wing polyphenism and conspecific egg cannibalism affects developmental and reproductive performances of Chrysoperla carnea

Ahmed A. Rashed^1*Marwa M. Ramadan¹Amged El-Harairy^2*Mohamed H. Bayoumy¹

• ¹Department of Economic Entomology, Faculty of Agriculture, Mansoura universiy, Mansoura, Egypt
• ²Albrecht Daniel Thaer Institute for Agricultural and Horticultural Sciences, Faculty of Life Sciences, Humboldt University of Berlin, Berlin, Baden-Württemberg, Germany

Aphid polyphenism and egg cannibalism may have nutritional consequences on the development, survival, and reproduction of predatory insects. Although predators have the same probability of attacking winged and wingless morphs in natural conditions, an increment in the proportion of winged morphs dispersed under predation risk may have a negative effect on predator feeding by reducing the size of the wingless form available on the plant. Whereas, the rest of the wingless aphids may be richer in nutritional value than the dispersed winged aphids. Therefore, the nutritional consequences of aphid morphs and egg cannibalism on development, survival, 10-time fecundity and fertility, and time needed to get 10-times of eggs of Chrysoperla carnea have been addressed via series of trials. Wingless aphids accelerated the total development and increased survival of C. carnea compared to winged ones. Furthermore, feeding with the wingless form increased the 10-clutch fecundities and fertilities, and reduced the days needed to get 10-times of eggs. Neonate larvae of C. carnea that devoured two conspecific eggs took shorter time with an acceleration in the overall development of C. carnea. Immature mortality was higher in controls than in the cannibalistic treatment. Reproductive benefits were obvious in females permitted to consume two conspecific eggs during their first instar compared to those did not. But the time needed to receive ten ovipositions did not differ between both groups. These findings are ecologically significant because C. carnea females are able to adapt to the stresses imposed by nature without needing winged aphid prey to distribute their eggs widely, as their larvae can grow on their own eggs and gain developmental and reproductive benefits from such behaviour when prey availability or quality is low.