The biology and ecology of pine aphid, Eulachnus tuberculostemmatus (Hemiptera: Aphididae) and its demographic responses to environmental changes

Abstract

Eulachnus tuberculostemmatus (Hemiptera: Aphididae) is the most abundant aphid species attacking pine trees in Isfahan, Iran. 2 Population fluctuations of this species and its natural enemies were studied on Pinus brutia var. eldarica by weekly sampling. Its fertility-life table parameters were determined in the field in spring and summer 2016. Furthermore, effects of different temperatures (15, 20, 25, and 30 ∘ C) and irrigation regimens (well irrigated, moderately and highly drought-stressed) on its performance were investigated in the laboratory. 3 The aphid population reached its peak abundance between 11 April and 23 May. Also, a minor peak was observed between mid-November and mid-December. During the survey, no sexual morphs were observed. Most fertility-life table parameters of E. tuberculostemmatus were found to be significantly higher in spring than in summer. Aphids reared at 20 and 25 ∘ C had a significantly higher net reproductive rate, intrinsic rate of increase and finite capacity for increase compared to those reared at 15 and 30 ∘ C. Also, the aphid performed significantly better on highly drought-stressed trees, due to higher survival rate, female adult longevity and fecundity. 4 Population peaks of the four Coccinellidae predators Adalia bipunctata, Hippodamia variegata, Propylea quatuordecimpunctata and Coccinella septempunctata coincided with that of the aphid. Keywords Fertility-life table, intrinsic rate of increase, pine forest, Pinus brutia.