Perception of oviposition-deterring larval tracks in aphidophagous coccinellids Cycloneda limbifer and Ceratomegilla undecimnotata (Coleoptera: Coccinellidae)

Abstract

The ability of the aphidophagous coccinellids Cycloneda limbifer Casey and Ceratomegilla undecimnotata (Schneider) to discriminate between simultaneously provided clean paper strips and paper strips with oviposition-deterring larval tracks was studied after the ablation of different sense organs. Females oviposited similar numbers of eggs on paper strips with conspecific tracks and on clean paper strips only when deprived of both maxillary palpi. C. undecimnotata without maxillary palpi also did not differentiate between clean paper strips and paper strips with tracks of the coccinellid Leis dimidiata (F.). If both antennae and one maxillary palpus were simultaneously ablated, females of both species laid significantly more eggs on clean than contaminated paper strips. The results of this study indicate that females use contact chemoreceptors on maxillary palpi exclusively to detect oviposition deterring tracks of conspecific larvae.Intact females of C. limbifer laid significantly larger batches of eggs on paper strips with conspecific larval tracks, than on clean paper strips in blank test. In contrast, intact females of C. undecimnotata laid significantly smaller batches on paper strips with conspecific tracks than on clean paper strips in blank test. This is the first evidence of an opposite effect of conspecific oviposition deterring larval tracks on egg clustering in aphidophagous coccinellids.