The mating behaviour of two species of spiders in their natural habitat is described. A male Leucauge nigrovittata from Sumatra mated repeatedly with a newly-moulted adult female which he had been guarding. Each copulation was in response to a body-jerking ‘invitation’ display by the female. In Tylorida ventralis from Sulawesi, males and females copulated almost continuously from dawn until dusk over several days. Females switched from diurnal to nocturnal web construction during this time. After temporary separations, females were almost as likely as males to solicit the re-initiation of copulation. In both species the sexes are of approximately equal size. The possible adaptive reasons for the extended mating times in T. ventralis are discussed.

The behaviour of free-ranging groups of Callithrix aurita and Callithrix flaviceps, small-bodied omnivorous marmosets, was monitored at two sites (Cunha and Caratinga, respectively) in south-eastern Brazil during equivalent periods in consecutive years. Quantitative behavioural data were collected using a standard scan-sampling protocol, with scans being taken at 5-min intervals throughout the daily activity period. Data were collected during the wet season months of January and February at Cunha in 1993 and 1994, and during the dry season months of July and August at Caratinga in 1985 and 1986. In both cases, wet-season precipitation levels were considerably higher during the first year. Activity budgets, daily ranging and the foraging behaviour of both species were compared between years. Significant between-year differences were observed in several behaviour categories in both species, and were consistent with seasonal and longitudinal variation in resource abundance. In C. aurita, apparent changes in fruiting patterns resulted in a significant increase in exudate feeding in the second year, both in relative and absolute terms, but little change in prey foraging. By contrast, a marked reduction in arthropod prey in 1986 resulted in major changes in most aspects of C. flaviceps behaviour, with the exception of plant feeding. While consistent with behaviour patterns in other marmoset species, the numerous significant differences observed in the present study further highlight the problems associated with the evaluation of intertaxon differences in the behaviour and ecology of primates, in particular marmosets, on the basis of relatively short-term studies of a few individuals, often at only a single study site.

Daily and seasonal activity of the mountain tapir Tapirus pinchaque was measured along trails and at two salt licks in mature and secondary montane forests of the Central Andes of Colombia using active and passive infrared monitors. Daily activity of the mountain tapir showed a clear bimodal pattern, with maxima during the early hours of the day (5:00–7:00) and early hours of the evening (18:00–20:00). This bimodal activity pattern has also been found in radio-tracking studies of T. terrestris and T. bairdii. Overall, there was more activity in mature than in secondary forest and at lower (3100 m) than higher altitudes (3600 m). Night-time activity was higher during full moon than during quarter and new moons. There was no correlation between monthly rainfall and seasonal activity. The time the mountain tapir was at the salt licks varied between 1 and 190 min. Daily activity at Quebrada Paraiso salt lick (3400 m) showed a clear bimodal pattern with maxima around midnight (0:00–2:00) and midday (11:00–14:00). These patterns of diurnal and nocturnal activity of the mountain tapir could be used in combination with future radio-tracking studies to better understand habitat use by this species.

This study examines the ecology of a population of Geoffroy's side-necked turtle Phrynops geoffroanus inhabiting a polluted urban river in Ribeirão Preto city, São Paulo state, south-eastern Brazil. Adult turtles fed mainly on Chironomidae larvae and pupae (Chironomus cf. plumosus, 100% of occurrence frequency) and domestic waste, but they also consumed terrestrial items (cockroach, snails) and carrion. Juvenile turtles showed more feeding diversity than the adults and exhibited a trend for predation on Chironomidae pupae, but this is not reflected in resource partitioning. The elevated number of turtles (170–230 turtles/ha of river) and biomass (255–345 kg/ha of river) inhabiting this urban river is probably the result of the abundance of sewage and organic waste produced by humans, the absence of predators, and increased availability of nesting areas. Such factors convert this area into an environment highly advantageous for the survival of Geoffroy's side-necked turtle.

The giant mole-rat Cryptomys mechowi exhibits an extreme reproductive division of labour. Reproduction in the colony is restricted to a single breeding pair. Non-reproductive individuals do not breed unless removed from the colony and paired with unfamiliar conspecifics. Circulating basal concentrations of luteinizing hormone (LH) as well as LH levels measured in response to a single exogenous gonadotropin hormone (GnRH) challenge are not significantly different between the reproductive and non-reproductive groups of either sex. Neither non-reproductive males nor females are physiologically suppressed at the level of the pituitary, as they do not exhibit a reduced pituitary secretion of LH or decreased sensitivity to hypothalamic GnRH. Rather, reproductive skew seems to result from an inhibition to mate with familiar conspecifics. Familiar individuals housed in the absence of the breeding pair did not breed, whereas pairing unfamiliar individuals of the opposite sex resulted in sexual activity and recruitment. The results from the giant mole-rat suggest that reproductive skew may result from a predominantly behavioural repression in non-reproductive females arising from an incest avoidance mechanism.

This paper describes the mate locating strategies of male Australian carpenter bees Xylocopa (Lestis) aeratus Smith and X.(L.) bombylans (F.). Males of X. aeratus display three different mate locating strategies: (1) non-territorial patrolling near nests or flowers; (2) territorial defence of nests that contain unmated females; (3) non-resource territoriality (hill-topping). At the onset of the mating season, non-territorial patrolling and territorial defence of nests were observed in three out of four populations that were studied, while in a fourth population only non-resource territoriality was observed. Later in the mating season both territorial defence of nests and non-resource territoriality were observed in one of the populations. Male X. bombylans have only been observed using the non-resource territoriality. Males of all size classes used the same strategy at any one time, but males that were observed more than once in a territory were significantly larger, suggesting that larger males have greater territory-holding capacity. Upon encountering males, receptive female X. aeratus alternated low zigzag flights through the vegetation with high-velocity flights well above the vegetation, while males followed closely. This behaviour is interpreted as a test of the flight capacity of males, and is indicative of pronounced female choice. The mate locating strategies of the two species are compared with literature data from other xylocopine bees, and factors that might affect the choice of a particular mate locating strategy are briefly discussed.

Northern tuatara Sphenodon punctatus punctatus survive on about 26 islands off the north-east coast of the North Island, New Zealand. These rare, lizard-like reptiles include seabirds in their diet. The presence of the Pacific rat Rattus exulans on some islands has been implicated in the decline of tuatara populations through predation and competition for food. Pacific rats and tuatara eat similar dietary items, including seabirds. Seabirds have high levels of the long chain n-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The potential contribution of seabirds to the diet of tuatara was investigated by measuring the composition of plasma fatty acids and the concentrations of triacylglycerol and cholesterol of adult tuatara from Green Island (rat-free, numerous seabirds) and Coppermine Island (rat-inhabited, relatively few seabirds). The composition of plasma fatty acids differed between islands and sexes. Specifically, tuatara from rat-free Green Island had higher levels of the long chain PUFAs arachidonic acid, EPA and DHA compared to tuatara on rat-inhabited Coppermine Island, and males had significantly higher levels of DHA than females on both islands. Concentrations of plasma triacylglycerol and cholesterol were higher in tuatara from Green Island than Coppermine Island. Males had higher cholesterol but lower triacylglycerol concentrations than females. Differences in fatty acid composition and lipid concentrations between groups of tuatara imply differences in diet. Tuatara on the rat-free island evidently had a higher intake of n-3 PUFAs compared with tuatara on the rat-inhabited island. This is probably due to higher seabird consumption, or perhaps to the presence of other dietary items containing EPA and DHA. High concentrations of plasma triacylglycerol and cholesterol may be the result of a high intake of insect larvae. We recommend the direct investigation of the diets of northern tuatara and the consequences of differences in the composition of plasma fatty acids for reproduction.

The foraging behaviour of Cape clawless otters Aonyx capensis was investigated. Factors included: duration of dives, recovery times, processing times, hunting success, per cent time at the surface, and time foraging before each catch. Observations were made during the day on solitary adult A. capensis in a marine environment in False Bay, South Africa. There were significant differences in duration of unsuccessful dives, recovery times, and processing times as well as successful dives with various depths. Aonyx capensis prefer hunting at depths of 0.5–1.5 m. This is despite having a higher hunting success, catching larger, more energy-rich prey (fish), and shortest time foraging per catch, at depths of 1.5–2.5 m. Some of the data presented support the optimal breathing hypothesis, which predicts that both surface and dive times should increase for dives of greater depths. However, diving efficiency does not decrease with increasing depth, and percentage time at the surface does not increase with increasing depth. These are contrary to the optimal breathing hypothesis.

There is a vast literature on the reproductive behaviour of cichlid fishes, most of which describes spawning strategies and parental care. However, descriptive information on the early development of cichlids is scarce. In this study, embryos and larvae of laboratory-reared Cichlasoma dimerus are described. The early ontogeny is documented from oocyte activation until the beginning of the juvenile period. At a water temperature of 25 ± 0.5 °C and a 12:12 h photoperiod, cleavage is finished in 10 h and the first somites appear at 26 h of development. The larvae hatch during the beginning of the third day and are deposited by both parents in a pit they have dug out in advance. Yolk-sac larvae present three pairs of adhesive glands over the head, these transient larval organs being characteristic of substrate-brooding cichlids. After another 5 days, the fry swim freely and begin to feed exogenously. Since the yolk-sac is not completely reabsorbed until 2 or 3 days later, there is a period of combined endogenous and exogenous food supply. The juvenile stage is reached on the 42nd day from spawning.

An analysis of forelimb and hindlimb skeletal morphology of 15 passerine genera was performed to investigate the likely existence of an ecomorphological pattern relating morphology to migratory behaviour. Each genus was represented by a pair of species, one being sedentary and another migrant. Using a phylogenetic comparative method we found migrant species having longer sternum, deeper keel and longer coracoids than non-migrant species. Hindlimb morphology was not related to migration. These results are interpreted as adaptations for migrants favouring flight ability, as the larger the sternum and the coracoids the greater the surface available for attachment of the main muscles involved in active flight.

We examined 3747 teeth from 134 hares (Lepus sp.) collected at 46 sites in Israel to test whether variation in epigenetic occlusal characters was linked to ecogenetic or phylogenetic factors. Collection sites encompassed a wide range of ecogeographical and climatic regimes. We compared data from Israeli hares with occlusal characters of 160 cape hares L. capensis from East Africa and 68 brown hares L. europaeus from central Europe. Only three teeth (I1, I2, M3) did not show occlusal variation. Thirty-eight occlusal characters were derived from dental variants by dichotomous (0/1) scoring. Absence of association of character states among characters of single teeth indicated a lack of morphotypes. Epigenetic differentiation among hares from northern, central and southern Israel, and the two East African, and two central European samples, was revealed by pairwise C. A. B. Smith's ‘mean measures of divergence’ (MMD), based on frequencies of character states. Cluster analyses of MMD values revealed little epigenetic differentiation between northern and southern Israeli hares, but greater differentiation between central European and East African hares. Concordance of the MMD matrix with linear geographical distances among sampling regions was demonstrated by a Mantel test. No frequencies of character states exhibited significant changes across the climatic parameters among hares from northern and southern Israel. But the individual folding index, which expresses the degree of enamel on the occlusal surface, slightly decreased from north to south. Our results support a phylogenetic interpretation of occlusal character variation. Despite distinct differences in external appearance, hares from northern and southern Israel probably comprise a single species that encompasses two closely related geographical populations with a probable area of overlap. Israeli hares are intermediate between European brown hares and East African cape hares, with a slightly closer relationship to the cape hares.

Three Iceland gull taxa were defined mainly from adult wingtip melanism. Up until about 1860, nominate glaucoides (no melanism) was known to breed from Greenland to western High Arctic Canada, but by about 1900 it was essentially confined to Greenland. Until 1860, thayeri (most melanism) was known only from western High Arctic Canada, but from 1900 to 1980 it was found throughout High Arctic Canada and in a small part of north-west Greenland. At high latitudes in Canada it replaced glaucoides, with which it was formerly sympatric in the west and probably interbred. The first known kumlieni (intermediate, variable melanism) were from west Greenland in the 1840s, and by 1900 the western and northern limits of most of its breeding range in the eastern Canadian Low/High Arctic were known. The range of kumlieni lies between those of thayeri and glaucoides and overlaps both; kumlieni bred in Greenland by 1964. It freely interbreeds with thayeri and probably with glaucoides. Winter ranges of glaucoides and thayeri have changed little since they were first determined for glaucoides by 1860 and for thayeri by the 1920s. However, winter adult kumlieni was unknown from Greenland to the British Isles until 1900; there were a few records prior to 1915 and progressively more after 1950. The study adds to the evidence that kumlieni represents introgressive hybridization by western thayeri into eastern glaucoides.

D. N. Weir died 15 August 2000.

Seasonal body weight changes were investigated in red and grey squirrels in spruce-dominated conifer plantations in the north of England. Annual seed food availability, particularly in the spruce plantations, varies markedly and is characterized by years with large cone crops (‘mast crops’) followed by several years of intermediate or low crops. The last mast crop in Kielder Forest District occurred in 1991 and we studied the two squirrel species when food availability was intermediate and low between 1992 and 1999. Neither red nor grey squirrels in the conifer plantations significantly increased their body weight for the autumn or winter. The responses of red and grey squirrels to the different foraging conditions in deciduous and conifer woodlands and the accumulation of seasonal fat stores may have to be seen in the context of habitat type and the pattern and predictability of seed availability. Our findings suggest that fat accumulation is likely to be less pronounced in conifer habitats where autumn and winter food supplies are more predictable, and manoeuvrability to feed on cones in the canopy is important.

The effect of diet quality on basal metabolic rate (BMR) over time was studied in female Octodon degus. Degus fed on a low-quality diet maintained a constant BMR over time, while those fed on a high-quality diet showed an increased BMR after 30 days. After 120 days of dietary acclimation, individuals fed on a high-quality diet exhibited comparatively higher BMRs. Thus, we hypothesize that when environmental food quality is high, degus are able to increase their BMR quickly, allowing high rates of biosynthesis.

Genetic diversity in four populations of the Eurasian badger Meles meles from Denmark was estimated by allozyme electrophoresis. Low genetic variability was found within populations as compared to the variability found in badger populations from other countries, whereas significant genetic differentiation was found between populations. The low genetic variability and the differentiation between populations is explained by the fragmentation of the Danish landscape, which reduces the effective population size of local populations and the gene flow between them. Low genetic variability found for Danish badgers also supports the hypothesis of a rapid recolonization following the last glaciation.

Echinostoma sp. use larval anurans as intermediate hosts. The cercariae enter the tadpoles via the cloacal opening and form metacercarial cysts in the kidneys, pronephroi, and Wolffian ducts. To examine the distribution of Echinostoma metacercariae in Rana sylvatica and Rana clamitans tadpoles, 200 individuals of each species were exposed to free-swimming cercariae. There was a significant left:right bias in the distribution of metacercariae within both R. sylvatica and R. clamitans tadpole hosts, with trematodes preferentially encysting in nephric structures on the right side. In R. sylvatica and R. clamitans, respectively, 56.7% and 96.8% of the metacercariae were on the tadpoles' right side. Asymmetry in the distribution of parasites followed the direction of the asymmetry in tadpole kidney size, but was much greater. Trematodes preferentially encysted in the head kidneys of R. clamitans, which regress at metamorphosis. The right head kidney was the most commonly infected structure in R. clamitans tadpoles, containing 72.7% of all cysts in that species. Despite the preference of trematodes to encyst in the head kidney, there was no correlation between the number of cysts in the right kidney and the number in the right head kidney. This suggests that limited space in the head kidney does not influence metacercarial formation in the kidney proper. The high frequency of unilateral encystment in both anurans, and in the head kidneys of R. clamitans, may be the result of a co-evolved relationship that ultimately benefits both the host and parasite by ensuring host survival.