Examination of an altered bar code on a vehicle tax disc.

Altered vehicle excise licences (tax discs) are regularly submitted for questioned document examination in order to reveal the original vehicle details. A bar code printed on tax discs permits the electronic storage and transfer of vehicle licensing information. In a recent case involving a tax disc on which the printed serial number had been partially removed, it was possible to restore and manually decode an obliterated bar code. This allowed recovery of the complete serial number of the disc and subsequent retrieval of the original entries.

Mating patterns, relatedness and the basis of natal philopatry in the brown long-eared bat, Plecotus auritus.

The brown long-eared bat, Plecotus auritus, is unusual among temperate zone bats in that summer maternity colonies are composed of adult males and females, with both sexes displaying natal philopatry and long-term association with a colony. Here, we describe the use of microsatellite analysis to investigate colony relatedness and mating patterns, with the aim of identifying the evolutionary determinants of social organization in P. auritus. Mean colony relatedness was found to be low (R=0.033 +/- 0.002), with pairwise estimates of R within colonies ranging from -0.4 to 0.9. The proportion of young fathered by males in their own colony was investigated using a Bayesian approach, incorporating parameters detailing the number of untyped individuals. This analysis revealed that most offspring were fathered by males originating from a different colony to their own. In addition, we determined that the number of paternal half-sibs among cohorts of young was low, inferring little or no skew in male reproductive success. The results of this study suggest that kin selection cannot account for colony stability and natal philopatry in P. auritus, which may instead be explained by advantages accrued through the use of familiar and successful roost sites, and through long-term associations with conspecifics. Moreover, because the underlying causes of male natal dispersal in mammals, such as risk of inbreeding or competition for mates, appear to be avoided via extra-colony copulation and low male reproductive skew, both P. auritus males and females are able to benefit from long-term association with the natal colony.

Outbreeding increases offspring survival in wild greater horseshoe bats (Rhinolophus ferrumequinum).

The factors influencing the survival of greater horseshoe bat (Rhinolophus ferrumequinum) offspring born over seven years at a maternity colony in south-west Britain were studied. The effects of a range of phenotypic and maternal variables were analysed using a historical data set. In addition, the influence of two genetic measures on mortality, individual heterozygosity and a new measure of outbreeding, termed mean d(2), was assessed. Logistic regressions were undertaken with survival modelled as a binary response variable. Survival to two life stages was studied for each variable and all models were developed for both sexes separately and together. Only one variable, mean d(2), was significantly associated with survival. Male offspring with high mean d(2) scores were more likely to survive to their first and second summers. The influence of mean d(2) was not due to a single locus under selection but a wider multilocus effect and probably represents heterosis as opposed to solely inbreeding depression. Therefore, the extent to which an individual is outbred may determine survival more than widely used phenotypic characteristics such as size and mass. Mean d(2) may reflect immunocompetence, which influences mortality. Protection of mating sites in order to facilitate gene flow and, therefore, outbreeding may help to promote population stability and growth.

Genetic diversity and introgression in the Scottish wildcat.

This paper describes a genetic analysis of wild-living cats in Scotland. Samples from 230 wild-living Scottish cats (including 13 museum skins) and 74 house cats from England and Scotland were surveyed for nine microsatellite loci. Pelage characteristics of the wild-living cats were recorded, and the cats were then grouped into five separate categories depending on the degree to which they conformed to the characteristics attributed to Felis silvestris Schreber, 1775. Allele frequency differences between the morphological groups are greater than those among the three house cat samples. Analysis of genetic distances suggests that more of the differences between individuals can be explained by pelage than geographical proximity, and that pelage and geographical location are not confounded. Ordination of the genetic distances suggests two main groups of wild-living cats, with intermediates, and one group is genetically very similar to the house cats, while the other group contains all cats taxonomically identified as wildcat based on morphology. A genetic mixture analysis gives similar results to the ordination, but also suggests that the genotypes of a substantial number of cats in the wildcat group are drawn from a gene pool with genotypes in approximately equilibrium proportions. We argue that this is evidence that these cats do not have very recent domestic ancestry. However, from the morphological data it is highly likely that this gene pool also contains a contribution from earlier introgression of domestic cat genes.

Genetic variation and population structure in the endangered greater horseshoe bat Rhinolophus ferrumequinum.

Following a dramatic decline last century, the British population of the endangered greater horseshoe bat Rhinolophus ferrumequinum is highly fragmented. To examine the consequences of fragmentation and limited dispersal on patterns of genetic structure and variation, we used microsatellite markers to screen bats from around 50% of the known maternity colonies in Britain, and two areas from continental Europe. Analyses revealed that Welsh and English colonies were genetically isolated. This, and lower variability in Britain than north France, may result from either genetic drift, or the species' colonization history. Gene flow among most neighbouring colonies was not generally restricted, with one exception. These findings have important implications for the ongoing conservation management of this species.

Parentage, reproductive success and breeding behaviour in the greater horseshoe bat (Rhinolophus ferrumequinum).

Female greater horseshoe bats form maternity colonies each summer in order to give birth and raise young. During the mating period, females visit males occupying territorial sites, copulation takes place and sperm are stored until ovulation occurs, normally in April. Using microsatellite markers and a likelihood method of parentage analysis, we studied breeding behaviour and male reproductive success over a five-year period in a population of bats in south-west Britain. Paternity was assigned with 80% confidence to 44% of young born in five successive cohorts. While a small annual skew in male reproductive success was detected, the variance increased over five years due to the repeated success of a few individuals. Mating was polygynous, although some females gave birth to offspring sired by the same male in separate years. Such repeated partnerships probably result from fidelity for either mating sites or individuals or from sperm competition. Females mated with males born both within and outside their own natal colony; however, relatedness between parents was no less than the average recorded for male female pairs. Gene flow between colonies is likely to be primarily mediated by both female and male dispersal during the mating period rather than more permanent movements.

Genetic structure of fragmented populations of red squirrel (Sciurus vulgaris) in the UK.

The relationships among 207 squirrels from 12 locations in the UK and three in mainland Europe were examined using mitochondrial DNA (mtDNA) control region sequence. Twenty-six haplotypes were detected, many of which were population specific. Eighty per cent of the populations analysed contained two or more haplotypes. Hierarchical analysis of molecular variance showed the majority of genetic variation to be partitioned among populations. Genetic diversity varied considerably within the UK, and conformed to no obvious geographical trend. The populations in Argyll and Spadeadam Forest showed the highest levels of variation in the UK. However, the greatest genetic diversity was seen in Bavaria, southern Germany where six unique alleles were detected in a sample of 10 individuals. Phylogenetic analysis revealed no evolutionary divergence between UK and mainland European haplotypes. We conclude that, within the UK, the genetic patterns observed are most likely to be explained by the effects of genetic drift which has occurred since the isolation of populations during the past few hundred years, hence we cannot detect any underlying phylogeographic pattern. Therefore, the use of larger, geographically distinct populations within the UK for augmentation of small isolated populations is unlikely to pose problems of genetic incompatibility. Further, the role that demographic factors may have in complicating the application of current genetically based management unit criteria is likely to need further attention.

Can skull morphology be used to predict ecological relationships between bat species? A test using two cryptic species of pipistrelle.

Can ecological relationships between bat species be predicted largely on the basis of morphology? This question was addressed by investigating skull morphology of two cryptic species of the pipistrelle bat. Since 45 Pipistrellus pipistrellus apparently eats larger prey than 55 P. pipistrellus, we predicted that it would have a larger overall skull size, a larger dentary apparatus, and a larger gape. To test these predictions, variables were measured from skulls of the two cryptic species, and comparisons made between them. In accordance with our predictions, overall skull size was larger in 45 P. pipistrellus than in 55 P. pipistrellus, and 45 P. pipistrellus had a longer lower jaw and the distance between the jaws at maximum gape was larger. In addition, 45 P. pipistrellus had longer upper canines, which may allow it to pierce harder prey items than 55 P. pipistrellus. Only some aspects of dietary differences between the two cryptic species could be explained by differences in skull morphology, and we suggest that empirical data, at least on diet and habitat use, are also required to explain mechanisms of resource partitioning among species in bat communities.