Are There General Patterns in Bark-Eating by Voles on Different Shoot Types from Woody Plants?

Abstract

Preferences by field voles (Microtus agrestis) for various shoot types of Salix myrsinifolia phylicifolia, S. pentandra, Populus tremula, Sorbus aucuparia, Betula pendula and B. pubescens were studied in series of laboratory experiments. Significantly more biomass and buds were taken from shoots collected in the uppermost parts of the Salix shrubs than from shoots from their basal part. A slightly higher palatability was recorded for long-shoots of Populus tremula than for short-shoots, but for Sorbus aucuparia we found no such difference. In general, more biomass was removed from shoots taken from individual trees in the reproductive phase than from non-reproductive trees (Betula pendula, B. pubescens and Sorbus aucuparia). The above results are discussed in relation to current theories on the feeding pattern by herbivores as influenced by plant defences.