The diet of southern African carnivorous slugs of the endemic family Chlamydephoridae is discussed. At least three species, Chlamydephorus bruggeni, C. burnupi and C. sexangulus, are predators of pill-millipedes Sphaerotherium sp. The feeding behaviour of C. sexangulus is described in detail and illustrated. It is suggested that the prey, once captured, is killed or immobilized by the introduction of a toxin through the intersegmental membrane joining the millipede's skeletal plates. The source for such a toxin may be the anterior pedal mucous gland. Predation on sphaerotheriid millipedes may be a behavioural apomorphy associated with a clade within the Chlamydephoridae, including taxa with longitudinal body keels and distinctive radula morphology, but it is evidently not confined to this clade. Whether the diet of such millipede-eating slugs is limited to millipedes is unknown, but it is probable that at least some chlamydephorids feed on more conventional prey such as snails and earthworms.

Nephila edulis is a spider with large body size variability in males and females. Genital characters show negative allometric values compared to somatic characters. In males, the embolus (the most important structure for sperm transfer) had a significantly lower coefficient of variation than body size. This suggests that male genitalia are under stabilizing selection favouring intermediate size. Female N. edulis showed a trend similar to males regarding allometric values in genitalia. In females, however, the variation coefficient in a specific genital character crucial for successful copulation did not differ from that of indicators for overall body size. This suggests that in Nephila the genitalia of the females experience less stabilizing selection than those of the males. In male and female genitalia, the mode of selection seems to cause developmental instability not in degrees of fluctuating asymmetry but in the degree of data scatter which indicates a lower coefficient of determination.

Movements and group structure of giraffe Giraffa camelopardalis were studied in Lake Manyara National Park, northern Tanzania. The giraffe population in Manyara had increased from 60 to 85 individuals between the early 1980s and 1991. This increase may have been the result of an increase in browse availability as a result of a dramatic decline in elephant numbers, and bush encroachment following a series of anthrax epidemics that killed impala. Giraffe densities in Manyara are high compared to other areas within the Masai ecosystem, and Manyara probably serves as a dry season refuge. Females were found in small, yet unstable groups, while males associated randomly with each other. Neither males nor females were confined to single localities, although home ranges were small compared with studies in areas with low giraffe densities. In one area within the park a more stable group was found, and resident males who were probably defending a temporary harem, engaged in necking contests with immigrant males. A comparison with other studies showed that giraffe density, home-range size, mobility and group stability differ across different habitats. The tendency that more stable groups are found in high density areas might be taken as evidence for the occurrence of resource defence polygyny in such areas.

Sixteen microsatellite markers were used to determine the genetic relatedness between adult female polar bears and their accompanying cubs for three recent occurrences of natural adoption recorded in the Canadian Arctic. The estimation of the degree of relatedness was powerful and provided a high degree of separation between first order relatives and unrelated individuals with the loci used. The analysis showed that the cubs were unrelated to their adoptive mothers and that the mothers were unrelated to one another. Although the circumstances and mechanisms whereby these adoptive events occurred are unknown, the data do not support kinship theory as an explanation for the exchange of cubs. We suggest that these adoptive events probably represent instances of the misidentification of cubs by adult polar bears.

A comparative study was conducted on the ontogenetic variation in morphometry of a total of 29 shell-bearing molluscan species occurring on an intertidal stony shore in south-western Japan. The relationships between shell size and total weight and between shell size and flesh weight were all highly significant on logarithmic scales with the slopes having values of about three. The arcsine-transformed proportion of shell weight out of total weight varied among and within different morphological/taxonomic groups, ranging from 58.6% in Acanthochiton defilippi to 76.4% in Nerita albicilla. The allometry of shell weight was analysed by regressing the arcsine transformed values of the proportion of shell weight against total weight in each species. The slope (β) of the regression varied substantially among different taxa, with all three possible cases, i.e. β > 0, β [ape ] 0 and β < 0, being observed. Thus, depending on molluscan species, the proportion of shell mass either (1) increases, (2) does not change, or (3) decreases with increasing body mass. Variation in the value of β was to some extent explained by the proportion of shell mass of young individuals of each species; species with relatively high proportions of shell mass in small individuals tended to have low β. Interspecifically, it was shown that shell mass scaled in proportion to body mass for this assemblage of 29 species. Consideration was given to the theoretical background of variation in shell morphometry, with particular reference to the shell as a defence structure.

The shallow, offshore, hypersaline (∼ 60‰), benthic marine environment of Shark Bay, Western Australia, is dominated by the cockle Fragum erugatum. This small (< ∼ 11 mm long) bivalve occurs in large numbers (4000/m2) and probably completes its life cycle in 1 year. Cyclones with a periodicity of ∼ 50 years have, over the last 5000 years, deposited huge numbers of the shells of F. erugatum onto the shore as windrows, creating the unique Shell Beach, or Hamelin Coquina. In most anatomical respects, F. erugatum is a typical cockle, with a powerful digging foot, siphons formed by fusion of the inner mantle folds only, plicate ctenidia with a ciliation of type C(1) and powerful rejectory currents on the visceral mass and mantle. It is thus able to collect filterable material and digest it. The labial palps are, however, reduced, allowing the ingestion of only the finest particles of food via the acceptance tracts in the ctenidial axes and distal oral grooves. The waters of Shark Bay are hypersaline and oligotrophic, so what is the food source that supports such large numbers of filter-feeding bivalves? Fragum erugatum possesses symbiotic zooxanthellae, as do its close relatives the giant clams (Tridacnidae), and probably obtains the same nutritional benefits from the association, which may facilitate survival in the hyperosmotic environment of Shark Bay. The association between giant clams and their zooxanthellae enhances shell growth and results in a long life expectancy and gigantism. Conversely, in F. erugatum the association facilitates a large population size (but short life expectancy), allowing it to dominate a unique, hypersaline, oligotrophic environment. Like giant clams, F. erugatum possesses a zooxanthella tube system linking the digestive diverticula of the stomach with the kidneys. Either accidentally or periodically, ingested zooxanthellae are transferred from the gut, via this tube, along with senescent zooxanthellae from the blood haemocoel, to the kidney tubules for lysosomal hydrolysis and eventual expulsion. In the light of this discovery, the functioning of the recently confirmed zooxanthella tube system in the Tridacnidae needs re-examination and re-evaluation.

Burrow systems of two coastal populations (El Alamo and Los Maitenes) of the social octodontid rodent Spalacopus cyanus were studied in central Chile. Tunnel systems were estimated to be up to 600 m long, ran at a depth of 15 cm and had a diameter of 6 cm. Tunnel openings were usually unplugged, and a minor preference toward southern and south-eastern direction of entrances was apparent. Nests, frequently found in the root system of Berberis actinacantha at a depth of 30 cm, consisted of grasses, roots and plastic bags. Nests serve for sleep, care of the pups and as latrines. Many staphylinid beetles of the genus Edrabius and other invertebrates were found in the breeding nests. Food chambers contained up to 13.2 kg of bulbs of the geophyte Dioscorea longipes collected by a single colony consisting of 26 animals (including 10 adults) and were frequently found at El Alamo. However, no bulbs were found at Los Maitenes, where the coruros forage above ground on leaves of Convolvulus arvensis within a radius of about 10 cm of the entrances. Apparently, the burrow design is also affected by food availability, soil quality, and colony size.

In this study, glycogen distribution during the development of larval salivary glands in two Drosophila species (D. melanogaster and D. auraria) was examined using the osmium tetroxide–potassium ferrocyanide technique at the ultrastructural level. Glycogen particles are found in big clumps in the salivary gland cells of D. melanogaster during the early third instar, mainly at the basal part of the cells; they are also found as scattered particles in the cytoplasm and very close to the apical plasma membrane during the secretory activity at this developmental stage. During the middle third instar, where the production of ‘glue’ secretory granules begins, glycogen particles are mainly scattered and they are seen near the Golgi complexes and secretory granules. No glycogen particles are seen during the late third instar and secretion of ‘glue’ secretory granules. Re-formation of glycogen begins after spiracle eversion. In the larval salivary gland cells of D. auraria, glycogen particles (scattered and in clumps) are seen in every developmental stage. In the larval fat body cells of both species, many huge clumps of glycogen particles are seen, independent of the developmental stage. These results indicate that glycogen provides an important source of energy during development of Drosophila salivary glands, but different species use glycogen at different metabolic pathways, according to their needs.

Reproductive data on individually known free-ranging red-necked wallabies Macropus rufogriseus banksianus were obtained over a 6 year period. Although this subspecies is essentially a non-seasonal continuous breeder, more young wallabies emerged permanently from the pouch in spring than in any other season. This partial seasonality of breeding was the combined result of seasonal variation in duration of pouch lives, a tendency for the first young of females to emerge permanently in spring, and seasonal variation in the incidence of reproductive interruptions. It is proposed that the adaptive significance of this partial seasonality is that it maximizes juvenile survival while maintaining a high reproductive rate.

Leaping primates are specialized for hindlimb-propelled locomotion within arboreal habitats. As a group, they include members of Galagonidae, Lemuriformes and Tarsiidae. Postcranial characters analysed here include humeral and femoral diaphyseal rigidity, articular surface areas and lengths. Data for leaper taxa are compared with corresponding data for less specialized small primates. The more generalized comparative primates include both closely related prosimians and distantly related platyrrhines (New World monkeys). In addition, the leapers are subdivided for further analysis according to body size and taxonomic association. Questions addressed concern the identification of functionally and/or phylogenetically linked traits in leaper postcrania. Results indicate that leapers as a group have relatively higher femoral diaphyseal rigidity and longer femora than do more generalized primates. These traits are also present in Pithecia pithecia, a platyrrhine leaper included for comparison. These enhanced properties probably function in resisting large hindlimb forces incurred during leaping, and in producing longer, more efficient leaps. Most of the large-bodied lemuriform leapers are further distinguished in having relatively bigger femoral heads and reduced humeral rigidity. The small-bodied leapers, galagonids and tarsiids, do not differ in either femoral head surface area or in any of the humeral properties from more generalized primates. Pithecia has a large femoral head like lemuriforms, but it is not reduced in humeral rigidity. Aspects of hip joint structure and mobility may be related to femoral head size in lemuriforms and Pithecia. Explanations regarding reduced lemuriform humeral rigidity are also explored. Differences between lemuriform primates are also present, most notably in aspects of the distal humerus. Indrids are characterized by relatively reduced trochleae, while many lemurids have relatively small capitula. These features are interpreted with regard to frequencies of suspensory behaviour and quadrupedalism.

Two new species of mites, Foveacheles (Proxistella) simulata n.sp. and Rhagidia longiseta n.sp., are described, and the little-known Foveacheles (Proxistella) terricola (C. L. Koch) is redescribed. All species were found inhabiting underground spaces in talus formations in the Czech Republic and Austria.

We studied the feeding apparatus of three species of northern ruminants representative of three feeding types: muskoxen Ovibos moschatus, Norwegian reindeer Rangifer tarandus tarandus and high Arctic Svalbard reindeer Rangifer tarandus platyhrynchus and Siberian musk deer Moschus moschiferus. The shape of the muzzle, the incisor arcade, the incisiform and the molariform teeth indicate that these species are selective feeders, irrespective of their body size or their position on the gazer-concentrate selector continuum of feeding types. Narrow muzzles seem well adapted for selective feeding on the diminutive but highly nutritious plants, or parts of plants, on tundra swards and Arctic-alpine meadows and enable the animals to maximize nutrient intake during the short summer. However, their small mouths presumably also restrict reindeer and muskoxen to taking small bites, thereby achieving low rates of dry matter intake when feeding on the very short swards in winter. This is partially obviated by two general strategies; a reduction of energy requirements in winter and, in Norwegian reindeer, migration inland to where foraging conditions are generally more favourable. In Svalbard reindeer, which have little access to lichens or other easy digestible plants in winter, rumen fill increases through the accumulation of slowly fermenting fibrous foods. Despite their narrow muzzles, reindeer and muskoxen are unable to avoid ingesting a certain amount of poor quality forage in winter and cope with this by appropriate modification of digestive function.

The uptake of volatile fatty acids (VFAs) from bacterial fermentation of forage in the rumen is enhanced by the presence of papillae which greatly increase the surface area of the mucosa of the rumen. The degree of papillation, expressed as the surface enlargement factor (SEF), seems to be closely related to the level of microbial activity and the rate of production of VFAs in the rumen. In several species of wild ruminants the SEF decreases markedly in winter, apparently in response to a decrease in the quality and availability of forage and also, presumably, in the level of ruminal microbial activity. Contrary to expectation, however, no reduction in the rate of production of VFAs in winter has been detected in semi-domesticated reindeer at natural pasture in northern Norway. We investigated the body mass, the composition and quality of the diet and the morphology of rumen papillae in adult female reindeer free-living at natural pasture. Animals were slaughtered in matched aged groups of nine on four occasions: in autumn (September) and winter (November, February and March). The composition and quality of the diet was determined by morphological and chemical analysis of plant fragments recovered from the rumen. The carcass mass of the animals did not differ significantly between collections. The animals ate vascular plants and lichens from 37 different genera. The composition of the diet varied little between months except for the inclusion of a substantial proportion (25.8% of fragments) of lichens in March. The mean density of rumen papillae increased from 55.6 papillae/cm2 in September to 75.7 papillae/cm2 in March (P < 0.001). All other parameters, including the length and perimeter of the papillae and the SEF of the rumen, were lower in March compared with September. However, the mean SEF increased from 8.8 in February to 10.6 in March (P < 0.05), indicating increased ruminal fermentation in late winter. We propose that the increase in the SEF in March might be associated with the increase in the proportion of lichens in the diet. Lichens are highly digestible in reindeer but do not score highly in conventional analyses of diet quality owing to the unusual chemical structure of the structural carbohydrates of which they are composed.