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

Many vespertilionid bats roost in proximity to roofing timbers and are therefore potentially exposed to organochlorines used as wood preservatives. Organochlorines elevate metabolic rate (MR) in some vertebrate species and any such effect in bats may threaten survival. The aim of this study was to determine whether sublethal exposure to lindane affected the body mass, food intake and MR of pipistrelle bats Pipistrellus pipistrellus and whether any such effects were modified by environmental conditions and the presence of co-roosting bats. Bats held indoors and receiving repeated doses of 50 μg of lindane lost mass (−0.26 g) relative to co-roosting bats receiving either 10 or 0 μg. 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 μg bat−1 3 days−1. The magnitude of this effect decreased as bats became heavier. Lindane significantly increased MR in bats and the effect was most pronounced in lean individuals. Environmental temperature and the presence of co-roosting bats altered the impact of lindane, the pesticide-mediated elevation of MR being greater under cold conditions. It was predicted that, under the environmental conditions of the experiment, exposure to 50 μg lindane bat−1 3 days−1 would increase 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