Mosquito consumption by insectivorous bats: does size matter?

Insectivorous bats have often been touted as biological control for mosquito populations. However, mosquitoes generally represent only a small proportion of bat diet. Given the small size of mosquitoes, restrictions imposed on prey detectability by low frequency echolocation, and variable field metabolic rates (FMR), mosquitoes may not be available to or profitable for all bats.

Foraging ranges of insectivorous bats shift relative to changes in mosquito abundance.

The need to develop effective management strategies for insectivorous bat populations requires an understanding of factors influencing habitat use. Availability of pest prey, such as mosquitoes is likely to be one such factor. To assess whether this is the case, we radio-tracked Vespadelus vulturnus Thomas (little forest bat), a predator of Aedes vigilax Skuse (saltmarsh mosquito), in saltmarsh and adjacent coastal swamp forest during periods of high and low Ae.

Ethics and transgenesis: toward a policy framework incorporating intrinsic objections and societal perceptions.

Concerns about the use of transgenic animals can be broadly separated into extrinsic factors, such as risks to human and non-human health, environment, economy and society, and intrinsic factors, such as spiritual, cultural, moral or otherwise personal beliefs about humans, animals and Nature. We examine the bases for making ethical decisions about the use of transgenic animals and the intrinsic beliefs that underpin common objections to their use. We explore the need for a policy framework based on a utilitarian approach to ethical decision-making, which balances costs with benefits, but which also acknowledges the intrinsic beliefs that lie at the core of much opposition to genetic modification of animals.