Effect of high temperature on the growth and reproduction of corn aphids (Homoptera: Aphididae) and implications for their population dynamics on the northeastern Iberian peninsula

The development, reproduction and longevity of corn aphids Rhopalosiphum pads (L.), Sitobion avenae (Fabricius) and Metopolopluum dirhodum (Walker) were studied at 18, 22, 25; 27.5 and 30 degreesC. Only nymphs of R. padi survived at 30 degreesC, but the adult reproductive capacity was very low. Rhopalosiphum padi performed better than Nf. dirhodum at all temperatures tested, and better than S. avenae over the range of 22-27.5 degreesC. The better performance of R. padi was due to a lower nymphal mortality, lower developmental and prereproductive times and a higher intrinsic rate of increase (r(m)). Sitobion avenae had a higher r(m) than M. dirhodum at all temperatures. The most suitable temperature for population development was approximate to 28.5 degreesC for R. padi, 26.5 degreesC for S. avenae and 24.5 degreesC for M. dirhodum, suggesting the ability of aphid populations to adapt to high temperatures in the Iberian peninsula. The role of temperature as a key factor in determining aphid population dynamics in the northeastern Iberian peninsula is discussed.