For many animals, strategies for optimally timing reproduction involve monitoring not only the physical environment, but also the social context. To explore the potential for social factors to modulate reproductive seasonality, the influence of social and environmental cues on birth timing was examined in greater spear-nosed bats Phyllostomus hastatus. Births were observed or dated from pup growth curves in three caves on Trinidad, West Indies, over 4 years. Nearly 40% of the variability in birth dates could be explained by environmental factors because birth dates differed significantly between years and showed consistent differences between locations that receive differing rainfall amounts. Nevertheless, the timing of births within caves and in captivity indicated that social cues also affect the timing and synchrony of births within female social groups. Within each cave, social groups differed significantly in mean birth dates. Two groups of greater spear-nosed bats brought into captivity and maintained without seasonal cues initially exhibited less birth synchrony than wild groups, but birth synchrony did not decline over 3 subsequent years. Further evidence for the influence of social cues on reproductive timing came from four females that were transferred between the captive groups and then gave birth in synchrony with their new group and out of schedule with their original group. Social cues influencing reproductive timing are unlikely to be volatile chemicals or other passively transferred cues, given that frequent prolonged physical contact did not increase birth synchrony between adjacent wild groups. Cues are more probably transferred actively between female group members, perhaps by grooming, or through mating with one attendant male.

An analysis of predator–prey ratio and guild constancy was made for 41 099 insects from 31 Acacia tree canopies in north-east Tanzania. A strong proportionality between predator–prey species richness, abundance and biomass was found, with reduced major axis slopes not statistically different from one. Predictions of five existing hypotheses to account for predator–prey ratios were tested: the energy ratio and common determinants of diversity hypotheses were well supported and most likely to explain the pattern reported here. Since predator–prey ratios can be considered a special case of the general guild constancy problem, it was also investigated whether species and biomass shares of guilds differed between six tree species and nine sampling localities. For most guilds no significant differences were found and both energy ratio and common determinants of diversity hypotheses might explain the observed general pattern of resource division in this ecological community.

Size and shape changes in the skull of South American spiny rats Proechimys spp. were investigated using geometric morphometrics. Six species were studied (P. guairae, P. poliopus, P. trinitatis, P. canicollis, P. mincae and Proechimys sp.) using 12 populations from Venezuela and Colombia. Proechimys poliopus, P. guairae and Proechimys sp. have undergone recent speciation coupled with chromosomal rearrangements. The separate analysis of size and shape showed that the only sexually dimorphic character is size; P. mincae is the smallest species and Proechimys sp. the largest. The populations are all recognizable by their shape, and populations of the same species share a common kind of shape modification. The prevalent non-uniform nature of morphological change in the skull shows how the various structures, such as those involved with audition, feeding and olfaction, are modified differently among species. Consequently, the modification of these different structures over a long time could reflect a progressive diversification of the microniche of each species.

Due to the unknown effects of long-term sympatry and interbreeding with the domestic cat, there is an ongoing debate about the characterization and taxonomic status of the wildcat Felis silvestris in Europe. Recent results on the morphology of wild-living cats in Scotland had revealed two morphological groups, T1 and T2, defined from a discriminant function (based on intestine length and limb bone size). We compared wild-living cats of each of these types from Scotland, together with known domestic cats, using a new technique: geometric analysis of 3D landmarks, with the goal of formalizing a definition of wildcats that would assist with their conservation. Eighty-five landmarks were digitized on a set of 85 skulls and subjected to superimposition techniques and univariate and multivariate analyses. Results showed that T1 cats generally clustered together while, despite showing their own morphological characteristics, T2 cats seemed closer to domestic cats. T1 cats had the largest skulls, the lowest braincase capacity index and demonstrated the greatest sexual dimorphism. Domestic cats were more heterogeneous, exhibiting a wide overlap between males and females. Analysing individual landmarks, females showed more differences between the groups, particularly in the orbito-nasal region. Our results not only provide a completely independent verification of the T1/T2 categorization, but also show that, as a practical tool, skulls can be identified as T1 using six linear skull characters selected from the 85 landmarks. From current evidence it is not logically possible to state conclusively that T1 cats are wildcats, but our results firmly support the hypothesis that they are furthest from domestic cats. Thus, the distribution of T1 cats in Scotland provides a possible basis for wildcat conservation through protection by area.

The parasite diversity of Norwegian lemmings Lemmus lemmus was studied in northern Fennoscandia during a moderate population peak in 1997–98. Our aim was to study the parasites of lemmings in their normal mountainous habitats in anticipation of the next great lemming migration in northern Fennoscandia into the coniferous taiga. The blood parasites (Hepatozoon, Trypanosoma and Bartonella) found, Frenkelia sp., which invades the brain tissue of the host, and the pulmonary fungus Chrysosporium (Emmonsia) sp., have been detected previously in the Norwegian lemming, but an unknown fungus, and oocysts of Eimeria spp. have not been reported from L. lemmus before. The Norwegian lemming was found to have an exceptionally species-poor helminth fauna. Only one species of cestode (Andrya sp.) occurring in lemmings at the adult stage was found, and the cestodes of carnivores that commonly parasitize voles at the larval stage were totally absent. The distribution and abundance of vectors, and sympatric definitive hosts of parasites are predicted to have a major role in determining the parasites that lemmings will encounter during their mass movements in new habitats. However, it is predicted that parasitism by adult and larval helminths is not markedly affected by the habitat change associated with the mass migration.

Scaling of avian brain:body mass throughout the diversification of the class was investigated by analysis of a large collection of adult brain and body masses. Linear regression model analysis of whole-class brain:body scaling resulted in scaling exponents ranging from 0.574 to 0.609, values which exclude several prior empirical and theoretical estimates. Taxonomic level-specific analysis of brain:body scaling was performed by major-axis regression of trait variances partitioned among levels of taxonomic distinction. Brain:body scaling exponents varied markedly among avian orders, but were not easily related to ecological differences among taxa. Avian brain:body scaling exhibited a partial taxon-level effect, in that scaling exponents vary with the taxonomic level of investigation. However, scaling exponents were greatest at the family level, a pattern not consistent with prior ontogenetic or genetic covariance models of trait diversification. Instead, it is suggested that initial diversification among birds was largely through body size diversification, while later diversification of families within orders contained a relatively greater degree of brain size diversification. Avian developmental mode, known to influence avian brain size at hatching, was associated with relatively little variance in adult brain mass. Avian brain:body diversification has occurred relatively uniformly in precocial taxa, while diversification within altricial taxa is marked by a relatively high degree of brain mass diversification among families within orders.

Moulting and copulation by the barnacle Tetraclita japonica attached to an intertidal concrete pier were observed continuously with a video camera housed in a plastic case in summer 1996 and 1997. In a total of 779 individual-day observations, 10 individuals became sexually receptive as functional females and 14 moulted. Copulation occurred not only immediately after, but also before moulting. Duration of receptivity varied from 2 min to nearly 12 h, during which functional females accepted between two to 582 penis insertions by between one to 11 surrounding males. Each insertion time was short, ranging from 0.6 to 42 s, with a median of 2.4 s. Sex role changes were observed between two animals located close to each other, the shortest interval for which was 3.3 h. No significant size differences were detected between functional males and females. A temporal pattern of copulation, with a high frequency of penis insertions of short durations, is discussed in relation to natural habitat conditions.

Controlled studies with baits containing the biomarkers iophenoxic acid or tetracycline were carried out to measure bait uptake by free-living badgers. The presence of these biomarkers was determined in badger plasma and dentition. The biomarkers were then incorporated into baits to quantify bait uptake by badgers in the field. Seven captive badgers were orally dosed with iophenoxic acid, which was subsequently measured in serial plasma samples for 18 weeks. Subsequently, field studies using baits marked with iophenoxic acid were carried out at selected setts in two study areas. In other experiments, five cage-trapped badgers were orally dosed with tetracycline and released. These badgers were subsequently re-trapped and the presence of tetracycline measured in sections of canine teeth. Field trials were also carried out using baits marked with tetracycline in four separate study areas. Badgers dosed with iophenoxic acid had elevated plasma iodine in comparison to a pre-dose baseline level. The elevations in plasma iodine could be detected throughout the sampling period. Field experiments using iophenoxic acid showed that c. 80% of wild badgers had ingested the marked bait. In addition, all five badgers dosed with tetracycline had tetracycline deposits in their canine teeth. Between 20% and 77.8% of badgers trapped in the tetracycline field trials were positive for uptake of the tetracycline-marked bait. Variation in the percentage of badgers marked was attributed to several factors including seasonal timing of bait deployment. Our results indicated that iophenoxic acid and tetracycline were effective biomarkers of bait uptake by badgers.

Hickmania troglodytes, the Tasmanian cave spider, belongs to a relict group with a scattered world distribution, and is of both phylogenetic and zoogeographic interest. It belongs to the superfamily Austrochiloidea (infra-order Araneomorphae) and shares characteristics with more advanced araneomorphs and primitive spiders in the infra-orders Liphistiomorphae and Mygalomorphae. The reproductive behaviour of H. troglodytes (including courtship, mating, egg-sac construction, brooding, emergence, and moulting behaviour) is described, providing the first such account for any member of the Austrochiloidea. Courtship in H. troglodytes is ritualized and involves distinct communicatory gestures (beating with the legs) by the male to identify and protect himself. Males use a pronounced curve in the metatarsus of the second leg to immobilize females during mating; this curve closely matches the contours of the female's cheliceral region. Both courtship and mating are protracted and each can last for over 5.5 h. The egg-sac is large and unusual, with a rigid internal structure that separates the egg mass from the silk walls, while the silk itself seems to be exceptionally resistant to fungal degradation. The young emerge from the egg-sac 8–10 months after laying, a period significantly longer than the typical emergence time of araneomorph spiders (4–8 weeks). It is suggested that the rigid internal structure and the silk of the egg-sacs may help to buffer and protect the eggs and young from biotic and abiotic factors during this extended pre-emergence period.

International Commission on Zoological Nomenclature