Energetic effects of sublethal exposure to lindane on pipistrelle bats (Pipistrellus pipistrellus)

Many vespertilionid bats roost in proximity to roofing timbers and are ther efore potentially exposed to organochlorines used as wood preservatives. Or ganochlorines elevate metabolic rate (MR) in some vertebrate species and an y such effect in bats may threaten survival. The aim of this study was to d etermine whether sublethal exposure to lindane affected the body mass, food intake and MR of pipistrelle bats Pipistrellus pipistrellus and whether an y such effects were modified by environmental conditions and the presence o f co-roosting bats. Bats held indoors and receiving repeated doses of 50 mu g of lindane lost mass (-0.26 g) relative to coroosting bats receiving eit her 10 or 0 mu g. Lindane increased the mealworm intake of bats, those with 0.45 g of body lipid increased their mealworm intake by 0.29 g DW night(-1 ) when given lindane doses of 50 mu g bat(-1) 3 days(-1). The magnitude of this effect decreased as bats became heavier. Lindane significantly increas ed MR in bats and the effect was most pronounced in lean individuals. Envir onmental temperature and the presence of co-roosting bats altered the impac t of lindane, the pesticide-mediated elevation of MR being greater under co ld conditions. It was predicted that, under the environmental conditions of the experiment, exposure to 50 mu g lindane bat(-1) 3 days(-1) would incre ase the 24-h MR of a 7.3 g bat by 3.4 kJ (15%) and that of a 6.3 g bat by 4 .8 kJ (23%). Such sublethal exposure might constitute a significant threat to free-living bats. (C) 1999 Elsevier Science Ltd. All rights reserved.