The role of aphids in wood formation. I. The effect of the Sycamore aphid, Drepanosiphum platanoides (Schr.) (Aphididae), on the growth of Sycamore, Acer pseudoplatanus (L.).
Abstract
In a field study in Scotland, two trees 10 m. high produced small leaves after heavy infestation with aphids during the spring, but the reduction in leaf size was far greater than would be expected from the quantity of nutrients removed by the aphids. The width of the annual ring was related to the size of the leaves and the number of aphids present through the year. A related study with eight trees showed that, after heavy infestation in spring, leaves falling in autumn retained large quantities of N. Calculations suggest that, in the absence of aphids, Sycamore could produce as much as 280% more stemwood each year. Laboratory experiments on saplings confirmed that aphid infestation can regulate leaf size, plant growth and the quantity of N in the leaves at leaf fall, and also showed that the width of the annual ring was related to the leaf area it supplied. The implications of the results are discussed from the point of view that the annual ring may be regarded as the area of vessels necessary to keep the leaves supplied with salts and water, rather than as a measure of the photosynthesis achieved. [Cf. F.A. 32 Nos. 1091, 2851-2. KEYWORDS: Acer pseudoplatanus insect pests, Hem. \ Drepanosiphum platanoides \ Hemiptera \ insect pests \ effects \ wood anatomy \ structure \ chemistry