Variability in the developmental parameters of bird cherry–oat aphid Rhopalosiphum padi (L.) (Homoptera, Aphididae) clones during the life cycle as a genotypic adaptation

Resumo

The complexity of life cycles, clonal structure of populations, and polymorphism underpin the ability of aphids to quickly evolve adaptations and inflict greater damage to crops. Harmfulness of aphids can only be limited by controlling changes in the adaptive norm that occur during seasonal cycles. In this study, timing of emergence of the main morphs and their developmental traits as reflected in 27 parameters are established for 9 heteroecious holocyclic clones of the bird cherry–oat aphid Rhopalosiphum padi (Linnaeus, 1758). On the basis of ranking the clones by the performance index, 3 clones with good performance and 4 clones with bad performance were identified. Three intermediate clones were discovered, which are capable of prolonged anholocyclic development and of overwintering at the active stage. Omission of the generation that develops on the primary host may change the population dynamics and harmfulness of aphids on secondary hosts. It is shown that performance of clones should be assessed by using demographic characteristics of morph development and phenological and behavioral peculiarities. The work was carried out under field conditions and in outdoor metal grid cages.