Cryptomys mechowi is a social subterranean mole-rat which inhabits the mesic regions of south-eastern and central Africa. Giant mole-rats live in colonies of up to 11 animals in which reproduction is normally restricted to the largest male and female in the colony. In this preliminary study on a laboratory-reared colony, the non-reproductive members of the colony could not be placed into clearly defined, work-related groups based on body mass. The colony showed a work frequency related division of labour. Reproductive animals performed little work, 3-4% of the total work. The non-reproductive caste was divided into two groups based on the amount of burrow maintenance activity: those performing between 7-11% of total work and those ranging from 15-22% of total work. Male members of the colony tended to perform more work than the females. The dominance hierarchy of the colony was found to be nearly linear, with a value of 0.83 calculated from Landau's linearity index. The reproductive animals were the most dominant in their respective gender. Dominance was not age-related. However, non-reproductive males tended to be more dominant than non-reproductive females. Social organization within the giant Zambian mole-rat is compared with other southern African Cryptomys species in the light of the eusociality continuum.

Larvae of Lepidoptera are mainly herbivores, and only the larval stages of Bradypodicola and Cryptoses pyralid moths are known to be specialized coprophages. Here, we report coprophagy as a main feeding habit for the larvae of another pyralid moth, Aglossa pinguinalis, on the basis of observational and experimental evidence. The larvae of this moth require two years to complete development, and construct silk tubes connecting the food source with a shelter chamber. Larvae of A. pinguinalis were mostly found inside caves, where they were about 700 times more abundant than in the open field. Inside the caves, observational results indicate that 98% of the larvae fed mostly on excrement and only 2% were recorded as eating other kinds of detritus (decayed mushrooms). No larvae were recorded eating plant detritus in the censuses nor in experimental detritus patches. The larvae did not show preferences for different types of excrement in the caves. Experimental dog and sheep excrement corroborated this result, showing that the abundance of larvae did not differ between these two excrement types over the entire study. We suggest that habitat selection of A. pinguinalis is ecologically similar to the trophic specialization of Bradypodicola and Cryptoses, in spite of the differences in natural history traits among these moths. Feeding on dry excrement inside caves, or in buried sloth dung, may reflect the constraints for Lepidoptera successfully to colonize excrement: in more exposed excrement, they cannot compete with other coprophagous specialists owing to the lack of parental care (e.g. resource relocation) and slow growth rates. We hypothesize that coprophagous Lepidoptera will be restricted to competition- and predation-free habitats and resources, feeding on excrement inside caves and animal burrows.

We report on a comparative scanning electron microscopical study of trophi morphology of the two species making up the Class Seisonidea of Phylum Rotifera. The trophi of the two are generally similar, with morphological differences being interpreted as the result of adaptations to different food sources: the trophi of Seison nebaliae are adapted to particle-feeding, that of Seison annulatus probably functions by piercing the integument of the host using the fulcrum tip, and subsequently sucking out haemolymph. This difference in feeding ecology is believed to contribute to the co-occurrence of both species on the same host. A new hypothesis on the evolution of rotifer trophi is proposed.

Among insects, the modified labium of Stenus species is one of the most specialized prey-capture structures. However, the question of its adaptive value has remained unanswered, since many species make use of their mandibles as an alternative capture technique (Bauer & Pfeiffer, 1991). In order to elucidate the biological significance of the specialized labium, within- and between-species comparisons of the performance abilities (i.e. velocity, mode of prey seizure, range, rate of occurrence and capture success) of both capture techniques were carried out. These investigations were performed in standardized prey-capture experiments, primarily by means of video-recordings and prey-capture cinematography. In addition, direct observations under semi-field conditions concerning habitat choice and searching behaviour were used to assess possible selection factors arising from the environment.

In standard experiments, most investigated species catch springtails much more successfully with the labium than with the mandibles, thereby stressing the selective value of the labium. The marked capture success of the latter is attributable to its large range, its high capture velocity and its capability of fixing prey at the moment of contact. The prey-capture experiments revealed interspecific differences in agility and reaction ability, which, to some extent, can be explained by differences in eye morphology. Some agile species, which usually forage on bare ground (e.g. S. comma), depend on the labium capture mechanism to a lesser degree. However, most species are not agile and forage in densely structured habitats such as plant debris or vegetation. The specialized labial apparatus of Stenus is thought to provide a biological advantage in that it permits these predators, in spite of their limited reaction ability and agility, to catch prey that are capable of rapid escape responses.

Observations of the external morphology of wild-caught and captive male brown long-eared bats (Plecotus auritus) revealed a marked seasonal pattern of spermatogenesis, similar to that established by histological examination of other temperate-zone vespertilionids, with a peak in testes size in August and a lag between testicular growth and epididymal distension. This was followed by complete cessation of spermatogenesis and shrinkage of the testes to prepubertal size. The period of peak spermatogenesis coincided with a reduction in the incidence of torpor and also a decline in body mass. This suggests that torpor and spermatogenesis may be incompatible in this species. Outside the season of testicular growth and epididymal distension, sexual maturity could not be confidently determined in P. auritus by the pigmentation of the tunica vaginalis surrounding the epididymis, a characteristic which has become established in other species. Instead, the size and shape of the caudae epididymides appeared to be a better criterion for defining sexual maturity in this species. Most males underwent testicular growth and epididymal distension, and were assumed to have reached sexual maturity, at an age of 15 months. However, some individuals (29%), particularly those in good condition (relatively heavy individuals), showed a degree of testicular and epididymal development in their first autumn, i.e. at 3 months of age, indicating that the onset of puberty may be dependent on body condition. Poor body condition was associated with delayed spermatogenesis in adult males.

We use information on the at-sea distribution of radio-tagged seals to identify the summer foraging areas used by 31 harbour seals from two different haul-out sites in the Moray Firth, N.E. Scotland. We then determine whether seals tend to occur over particular sediment types or water depths as hypothesized by Härkönen (1987b), and assess whether local geographical variations in diet composition can be related to local differences in available foraging habitat.

The majority of seals foraged within 30 km of their haul-out site, consequently there was broad overlap between the foraging areas used by animals from the same site, but little overlap in the areas used by seals from different sites. Most seals foraged in water depths of 10-50 m with mainly sandy sea-bed sediments. Data on the distribution of dive depths of five seals which were fitted with time-depth-recorders indicated that seals were generally diving on, or close to, the sea-bed. Occasional pelagic dives between the more common benthic dives were also observed. Between-site differences in the seals' use of different water depths and sea-bed sediments suggest that local geographical variations in diet were related to local differences in foraging habitats, but that habitat use also differed between individual seals.

Analysis of 904 small carnivore scats collected over a two-year period in a seasonal forest in the south-western Central African Republic yielded the remains of 732 shrews, rodents (<1 kg), and bats comprising at least 34 species. Most scats belonged to the long-nosed mongoose, Herpestes naso, the numerically dominant carnivore in the study area. Shrews were the principal small mammal prey with respect to number of individuals and frequency of occurrence. The mean monthly frequency of occurrence of shrews was 21.7% and of small rodents (<100 g) was 20.8%. Both shrews and small rodents occurred significantly more often in scats collected during dry season months, and live-trapping of rodents over a 22-month period revealed similar peaks in availability. In contrast to many mammalian carnivores, shrews did not appear to be used as an alternative prey source: not only did consumption levels of both prey types fluctuate in synchrony, but the availability of rodents apparently had no effect upon the likelihood of including shrews in the diet. Preferential use of small mammals by long-nosed mongooses was tested for the 10 rodent species for which abundance indices were calculated. Mongooses preyed selectively on several rodent species (Praomys spp., Deomys ferrugineus, Stochomys longicaudatus, and Grammomys rutilans), while the most common rodent in the study area, Hylomyscus spp., was found in scats at lower frequencies than expected. In accordance with the habitat specificities of these ‘preferred’ rodent prey, it is suggested that mongooses and perhaps other small carnivores were foraging in micro-habitats characterized by higher-than-average vegetation understorey thickness where the simultaneous rate of encounter with arthropods, their main prey, and shrews was apt to be high.

As part of a study on the ecological strategies related to adaptation to the subterranean habitat of genus Ctenomys (tuco-tucos), a natural population of C. talarum was live-trapped at Necochea (Buenos Aires Province, Argentina) with the aim of providing information on its population ecology. Population size was consistently low throughout the study and was related to the low habitat productivity. Mortality rates were low, although for juveniles the estimations were higher than for adults. Individuals have an average life expectancy of 22-25 months, but some individuals lived at least three years. Reproductive activity started by July and ended by March, when last known pregnancies were recorded. This long reproductive season allowed a gradual incorporation of young over an extended period of time, with a restricted period of recruitment lacking. Sex ratio did not depart from 1:1 and appears to be density dependent. The spatial distribution of individuals was clumped and corresponded to the patchy distribution of suitable habitats. The results are compared and contrasted with those from previous demographic studies performed in other conspecifics as well as in other subterranean rodents.

Sexual segregation reported in many wild ruminants is generally assumed to result from either different habitat choices by adult males and females or ‘social factors’. In this framework, we studied group composition and habitat use of mouflon sheep (Ovis gmelini) over an annual cycle in the low-mountain range of Caroux-Espinouse (continental France). The analysis of group composition revealed segregation outside the rut, not only between the sexes, but also between the young (2-3 years) and old rams ([ges ] 4 years). Moreover, ewes, young rams, and old rams exhibited some differences in patterns of habitat use in the mid-rutting and lambing seasons, but showed similar patterns in winter and summer. These results, juxtaposed with those of studies of interactions and proximity between individuals within groups, suggest that segregation between age-sex classes has a strong social basis in mouflon sheep.

The level of visible (i.e. white or unpigmented) scarring on cetaceans varies greatly between species, particularly for intraspecific scarring in odontocete cetaceans. In some species, unpigmented intraspecific scars may act as an indicator of male ‘quality’ during aggressive social interactions. Evidence to support this hypothesis was found in 18 species of odontocete cetacean. These were the narwhal (Monodon monoceros), the sperm whale (Physeter macrocephalus), the Risso's dolphin (Grampus griseus) and the family Ziphiidae (with the exception of Mesoplodon ginkgodens). The evolution of such signalling is related to the fact that teeth are not required for feeding on certain diets, primarily cephalopod-based diets, and as a result the number of teeth has been reduced. However, some teeth have been retained, and selected, as weapons for male-male competition. This has resulted in an increase in the level of intraspecific scarring and the greater need for a signal of ‘quality’ to avoid costly and dangerous fights. As intraspecific scarring became this signal, the repigmentation rate of scars was reduced, leading to all scars remaining permanently unpigmented in these species.

We studied the behaviour of free-ranging female mouflon sheep (age 3-5 years) in the period periparturition. The study area is situated in the north-east of Germany (52°59′N, 13°50′E). For continuous data collection, we used the storage-telemetry-system ETHOSYS. Activity and foraging behaviour of five females were recorded every second by electronic sensors integrated in a collar round the sheep¨s neck (weight 300 g). Whenever the animals visit a special ‘link-station’, installed at a combined saltlick/feeder station, the recorded data are transmitted from the collar to the station and then to a laptop. In addition, we recorded continuously the presence of sheep at the saltlick using a camera-system, including a daylight and an infra-red camera.

Activity of female mouflon ranged from 8 to 10 hours daily during late winter. The animals spent the major part of that time feeding (70-80%). The sheep visited the saltlick every two to three days regularly. However, from late March to early April, every animal stayed away from the ‘link-station’ for about two weeks. This meant spatial isolation from social companions. When returning, these sheep were accompanied by a lamb. Parturition was assumed to take place during 2-3 consecutive days of markedly decreased activity. In the night from the first to the second day of this period, we found a unique activity pattern observed in all sheep. A short activity bout during the second half of the night was interpreted as the exact time of lambing. Spatial and temporal changes in behaviour during parturition are discussed with regard to other wild ungulates as well as domestic animals.

Population ecology and reproduction of the fat dormouse (Myoxus glis L.) were studied in central Germany in the years 1992 and 1993. Animals were captured in wooden live-traps twice a month, during trapping periods lasting three days each, and marked individually by tattooing. Demographic results show that, in three subpopulations, population structure differed extremely between 1992 and 1993. In 1992, more adult than subadult dormice occurred in the study area and the reverse was found in 1993. Subadults emerged from hibernation a little before or together with adult dormice. Adult males emerged significantly earlier than adult females. After a year with good reproductive success (1992), a total lack of reproduction was observed in 1993. Juvenile dormice were neither found in traps nor in nest-boxes. The assessment of gonadal states indicated that all males (adult and subadult) remained in a state of testicular regression throughout the year 1993. Also, no female was found lactating. Reproductive failure coincided with a lack of food resources in the autumn of 1993 (e.g. fruits of oaks and beeches). Body mass changes imply high energy expenditure prior to mating in adult males. It seems likely that males in years with low food availability do not invest energy in reproduction.

The indigenous wildcat, Felis silvestris Schreber, 1775, and the introduced domestic cat, F. catus L., have been sympatric in Britain for more than 2000 years. As a result of interbreeding, any distinction between these two forms has become obscured, although a range of morphological criteria (pelage patterns, body measurements, gut lengths, skull morphometrics) and genetic techniques (immunological distances, electrophoresis, DNA hybridization) have been used previously to distinguish between them.

A sample of 333 wild-living cats in Scotland was assessed for coloration and markings of pelage, standard body measurements and weights, and (for carcasses only) limb bone lengths, intestine lengths, and skull measurements. These cats were also classified as wildcat, hybrid, or domestic cat according to traditional pelage criteria.

Multivariate analyses on these variables, for adult cats, failed to show any clearly distinct groups. When each of the variables was analysed separately, only the distribution of limb bone and intestine length measurements suggested the possibility that two groups might exist. Group 1 cats had short intestines and long limb bones. Group 2 consisted of cats with long intestines and short limb bones. Although the characteristics defining cats in Group 1 were similar to those traditionally associated with wildcats, they exhibited a much broader range of pelage and coloration than traditionally described.

The groups exhibited a degree of geographical separation. The distribution of Group 1 cats was found to be related to certain environmental variables, namely mean annual temperature and land with poor potential for forestry and agriculture, suggesting that there may be a biological basis for the separation. The implications of these results on the identification and taxonomy of the wildcat are significant. The concept of the wildcat and the domestic cat as separate species can be challenged. The paper highlights the complexity and difficulties for conventional taxonomy when used as a means for distinguishing between a wild type and its domesticated form where there is interbreeding.

The social structure of three sympatric bat species occupying bat boxes in woodland in southern England was studied: Pipistrellus pipistrellus (pipistrelle), Plecotus auritus (brown long-eared bat) and Myotis nattereri (Natterer's bat). Before parturition, P. pipistrellus populations were heavily skewed towards solitary males. After parturition, the sex ratio was closer to unity. Recaptures of marked bats suggested that after parturition a resident male population of P. pipistrellus is invaded by a transient female population. The sex ratios of populations of P. auritus and M. nattereri were very close to unity, both pre- and post-parturition. The numbers of recaptures of individual bats were similar for both sexes in P. auritus and slightly higher for females in M. nattereri. In the mating season (August-October), solitary male P. pipistrellus were found with small groups (1-9) of females. In contrast, in both P. auritus and M. nattereri, mixed sex groups were found pre- and post-parturition, and roosting groups in the mating season contained up to 20 females and up to 10 males. The stability of female groups in P. auritus appeared to be higher than M. nattereri and P. pipistrellus as known females were found together more frequently. These patterns are discussed with reference to the possible differences in foraging and social behaviour.

The helminth parasites from more than 300 cetaceans stranded on the coast of England and Wales during the period 1990-1994 were identified, this being the largest organized survey of cetacean parasites yet undertaken. Thirteen species of cetaceans were examined, although the majority were common (harbour) porpoises Phocoena phocoena (n=173) and common dolphins Delphinus delphis (n=101). The parasites found included 11 species of nematode (Anisakis simplex, Pseudalius inflexus, Torynurus convolutus, Stenurus globicephalae, S. minor, Halocercus delphini, H. invaginatus, H. lagenorhynchi, H. taurica, Crassicauda boopis, Crassicauda sp.), five cestodes (Diphyllobothrium polyrugosum, D. stemmacephalum, Phyllobothrium delphini, Monorygma grimaldii, Tetrabothrius sp.), five digeneans (Campula oblonga, Oschmarinella albamarina, O. rochebruni, Lecithodesmus palliatus, Pholeter gastrophilus) and two acanthocephalans (Bolbosoma capitatum, B. physeteris). The results of this survey are tabulated and each helminth species is discussed in terms of its biology and pathogenicity.

One new genus and three new species of deep-sea holothuroids, taken by the South African Division of Sea Fisheries R.S. Africana II routine trawls, off the west coast of the Cape Peninsula in South Africa in 1959, are described. A new genus Psolidothuria, perhaps referable to the dactylochirotid family Vaneyellidae, is erected for the new species P. octodactyla. The remaining new species are Paracucumaria capense, in the dendrochirotid family Cucumariidae, and Laetmogone perplexa, in the elasipodid family Laetmogonidae. P. capense was originally described as Trachythyone ?parva (Ludwig) by Thandar (1991). The diagnosis of the family Vaneyellidae is amended to accommodate the new genus.

During three breeding seasons, 1994-96, the habitats of song thrushes were studied in north-east Essex, U.K., in 10 tetrads (total 40 km2) of mainly farmland habitat and 35 woods of differing sizes (range 0.1-57.0 ha). Within tetrads, only 6 (3.5%) territories were found in farmland. Gardens held 123 (71.5%) territories, though this habitat made up only 2% of the total area, while 39 (22.7%) were in woodlands (1% of total area). Population densities were much lower in the tetrads than in earlier studies; this may be an indication of the severe population decline that the species has recently undergone. Densities in gardens differed less from those of previous studies.

In the woodland study, the number of woods holding song thrush territories declined over the three years, while the proportion of total territories in the six largest woods increased. Densities in the woods were lower than those reported in earlier studies but the disparity was not as great as in farmland. Extinctions in the smaller woods was 20-30% per annum, a rate similar to that for gardens: population extinctions did not occur in the larger woods.

Some 40% of non-garden territories in the surveys of both tetrads and woodland plots were within 100 m of a garden. Gardens may be currently acting as a refuge for song thrushes and an understanding of the ecology of the species in different types of gardens may be important in current conservation efforts for the species.

The annual cycle of adult butterflies was studied at seven rocky outcrops located along an altitudinal gradient in a northern Spanish mountain area (Picos de Europa) with a Eurosiberian climate in 1993 and 1995. Both total abundance and number of species of butterflies peaked in summer at all study sites. The cumulative species number uniformly increased over the season until late summer. These results imply that butterflies concentrated their activity when temperatures were higher in the year. Regardless of their diversity and total abundance, timing of the flight period was later for assemblages at high altitude than for assemblages at low altitude. A similar trend in increasing delay in flight period was found when data were analysed separately for each species. The duration of the flight period of assemblages was correlated with abundance in 1993, but it was correlated with altitude in 1995. Most species tended to show shorter flight periods at high altitudes in both study years. These altitudinal changes in timing of adult flight are likely to be linked with effects of temperature on developmental rates of early stages of the life cycle. Changes in duration of the flight period, however, might be partly related to variability in species abundance.

We studied the foraging behaviour and energetics of the nectar-feeding bat, Leptonycteris curasoae (=L. sanborni), in the Sonoran Desert near Bahia Kino, Sonora, Mexico, using radio-telemetry, light-tagging, and focal plant observations to answer three questions: (1) How far do these bats fly in a night and at what energetic cost? (2) How do they harvest nectar and pollen from columnar cacti that offer large but temporally variable nectar rewards? (3) What are the implications of their foraging behaviour for gene flow within populations of their food plants? L. curasoae visited flowers of three species of columnar cacti in April through June. Many bats roosted on Isla Tiburon 20 km from the Mexican mainland and commuted about 30 km to the mainland to feed. Bats flew for about 5 h each night for a total distance of about 100 km. Individuals foraged alone or in small groups in overlapping areas of 1-3 km2; and visited the same feeding areas on successive nights. Within feeding areas, bats visited the flowers of many cactus plants, visited most flowers <5 times, and removed about 0.1 mL of nectar per visit. Although bats flew nearly continuously early in the evening, they did most of their feeding between 24:00 and 02:00. When visiting flowers of Pachycereus pringlei (cardon), bats apparently waited until flowers had accumulated 0.8 mL of nectar before feeding, which suggests that rates of nectar secretion influence the timing of feeding in these bats. We estimate that the daily energy budget of L. curasoae is at least 40 kJ and that bats make about 80-100 visits to cactus flowers to acquire this energy. Foraging areas typically contain thousands of cactus flowers, and thus food does not appear to be a limited resource for these bats during the spring. The cost-efficient flight of this bat makes it an excellent pollen vector for self-incompatible, widely spaced desert cacti.

The egg capsules and larvae of Engina armillata (Reeve) (Gastropoda: Buccinidae) are described for the first time. Its general ecology in the Cape d'Aguilar Marine Reserve, Hong Kong, is also described, the species occurring under stable boulders with a community of encrusting species, notably sedentary tubicolous polychaetes. The diet of E. armillata at Cape d'Aguilar consists of serpulid and spirobid polychaetes. Of the four commonest such species, Hydroides elegans was preferred to Pomatoleios kraussi, Simplicaria pseudomilitaris and Spirorbis foraminosus. Consumption rates by E. armillata varied considerably amongst individuals, but generally ranged between 1.2 and 6.5% of predator dry weight day-1 during conditions wherein prey quantity was maintained. Such a figure is low when compared to other boring naticid and muricid predatory gastropods which spend much time and energy accessing their prey. The ready availability of easily accessible prey may account for the low consumption rate of E. armillata (as also seen in other non-boring predatory gastropods) and explain its apparent specialist feeding habits.