Insular populations typically occur at higher densities, have higher survivorship, reduced fecundity, decreased dispersal, and reduced aggression compared to their mainland counterparts. Insularity may also affect mating system and genetic population structure. However, these factors have not been examined simultaneously in any island vertebrate. Here we report on the ecological, behavioural and genetic characteristics of a small carnivore, the island fox Urocyon littoralis, from Fraser Point, Santa Cruz Island, California. Dispersal distances in island foxes are very low (mean 1.39 km, SD 1.26, range 0.16–3.58 km, n=8). Home-range size is one of the smallest (mean annual home range=0.55 km2, sd 0.2, n =14) and density is nearly the highest recorded for any canid species (2.4–15.9 foxes/km2). Similar to other fox species, island foxes are distributed as mated pairs that maintain discrete territories. Overlap among mated pairs was always high (mean 0.85, sd 0.05), while overlap among neighbours (mean 0.11, sd 0.13), regardless of sex, was low. Despite this high degree of territoriality, island foxes are not strictly monogamous. Four of 16 offspring whose parents were identified by paternity analysis were a result of extra-pair fertilizations. Mated pairs were unrelated, however, suggesting inbreeding avoidance. Substantial population differentiation was found between the Fraser Point subpopulation and one only 13 km away (Fst=0.11). We suggest that the primary effect of finite island area is to limit dispersal, which then influences the demography, behaviour and genetic structure of island fox populations.

The hypothesis that Brants' whistling rat Parotomys brantsii is a central place forager, whose foraging decisions are modified by (a) predation risk, (b) time of day, and (c) food choice, was tested. Field observations showed that whistling rats followed central place foraging rules for a single-prey loader and much of their food material was brought back to burrow entrances to feed on, with larger food items being carried back greater distances than small ones. Small food items were consumed in situ more often than large ones, suggesting that predation risk may also play a role in their foraging behaviour. Larger food items were preferentially stored at burrow entrances or carried underground, whilst smaller items tended to be consumed immediately. Individuals foraged more actively in the afternoon than in the morning and, although there was no tendency for individuals to eat more food at this time, far more food was stored or taken underground during the afternoon. Different foraging strategies were used for different plant species with some species preferentially eaten, and others stored or taken below ground more frequently. This study shows that the foraging behaviour of Brants' whistling rats is complex, and whilst they may follow simple central place foraging strategies, other factors such as the time of day and food plant species also influence their foraging behaviour.

Nectivory was studied in 90 species from the spider family Salticidae. Observations of 31 of these species feeding on nectar from flowers in nature was the impetus for laboratory tests in which all 90 species fed from flowers. That sugar, not just water, is relevant to salticids was implied by choice tests where salticids spent more time drinking from a simulated nectar source (30% sucrose solution) than from distilled water. Our findings suggest that nectar feeding may be widespread, if not routine, in salticid spiders.

Karyotypic and allozyme analyses were carried out on 55 individuals of Microtus subterraneus and M. majori from 19 populations in Europe and Anatolia. The occurrence of M. subterraneus in Asia Minor was proven. Standard karyotypes were found in M. majori (2n=54), M. subterraneus from Poland (2n=54), and central and south-eastern Europe (2n=52). Although the karyotype of M. subterraneus populations from Anatolia (2n=54), resembled that from Poland, there were apparent differences in the X chromosomes: it was larger and submetacentric (instead of metacentric) in the Anatolian populations owing to the presence of a large block of heterochromatin. The heterochromatic segment was also found to cause the size and shape differences in the X chromosomes between M. majori and European M. subterraneus (both in the 2n=52 and 2n=54 karyotypes). However, the location of this segment differed between the latter species and M. subterraneus from Anatolia. The distribution of the 2n=52 and both the 2n=54 karyotypes of M. subterraneus suggests that the Robertsonian fusion, distinguishing these different karyotypes, originated within the range of the species (i.e. within the 54-chromosome karyotype) and has spread subsequently towards its periphery. It is also suggested that both the fusion in European populations and amplification of heterochromatin in Anatolian populations are quite recent phenomena. The allozyme data indicate that gene flow is limited between populations of M. subterraneus and they are concordant with the isolation-by-distance model. There seems to be little correspondence between patterns of chromosomal and allozyme variation in M. subterraneus. Nei's genetic distance between M. subterraneus and M. majori was low (D=0.169), suggesting their recent divergence.

Adult annual survival rates estimated by mark–recapture for eight Greek populations of the tortoise Testudo hermanni were in the range 0.80–1.0 (mean 0.886). Estimates from growth rings for the same populations were in a similar range (0.84–0.95, mean 0.899). The average survival rate from the two methods was significantly positively related to mean adult body size (r=0.815) and negatively related to effective temperature (r=−0.880). A life table model was used to investigate the consequences of adult survival rate for optimum age at maturity and mean adult size of females. The basis of the model was the trade-off between increased reproduction from large adult size, and decreased survival to maturity from delayed age at maturity. The model showed that the observed variation in adult survival rates was more than sufficient to account for the variation of adult size among populations. The model thus predicted an even greater range of mean adult size than that observed. A negative correlation between growth rate and adult survival rate or age at maturity, as observed, was needed to fit the size data. The model supports the hypothesis that variation in adult size of T. hermanni in Greece is adaptive (rather than a non-adaptive environmental or phylogenetic effect) and due to variation in adult survival rates (rather than other factors such as juvenile survival).

The commonly reported freshwater snail Ceratophallus natalensis (Krauss) (Planorbidae) of eastern and southern Africa is shown here to be a composite taxon comprising at least three species. The species of Ceratophallus are found only in Africa and some Indian Ocean islands; they are distinguished by the structure of the penis, which is chitinized internally and may bear microspination. Ceratophallus natalensis (Krauss) has been often recorded as common in pools and marshes. According to observations on the genital organs reported here, this taxon comprises three species, C. natalensis, C. gibbonsi (Nelson) comb. nov. and C. yesimit sp. nov. No clear-cut conchological differences among them were evident. Anatomical observations were made on snails from 398 collectors' samples, providing many new locality records for this genus (details in Appendix). Ceratophallus natalensis and C. gibbonsi are widespread from Ethiopia to South Africa, whereas C. yesimit is known only from the Ethiopian Rift Valley. Though natalensis and gibbonsi are partly sympatric, the latter is associated with fully tropical climatic areas and comparatively permanent waterbodies, whereas natalensis is commonest in cooler areas and is abundant in seasonal rain pools. This study showed the penis of Ceratophallus to be stiffened by internal chitinous bands that apparently are unique in the Planorbidae and perhaps for all pulmonate molluscs. It is suggested that the microspinous penis of C. natalensis may be adapted to the function of sperm displacement. The chromosome number 2n=36 was observed for C. natalensis. Comparative data are given for Afrogyrus coretus (de Blainville) (Planorbidae), which in part of its range is sympatric with Ceratophallus and has a similar shell, but differs in having an external penial stylet. Although both groups are found only in the Afrotropical Region, they apparently differ in biogeographical history and phylogeny. In a cladogram where the first apomorphy is external chitinization of the penis, Afrogyrus is allied to Gyraulus, whereas Ceratophallus is more closely related to Planorbis.

This paper provides the first account of merycism in koalas (Phascolarctos cinereus), and in doing so, potentially sheds new light on the occurrence and significance of this behaviour in other herbivorous marsupials. Koalas fitted with acoustically sensitive transmitters, to monitor mastication and ingestive behaviour, were also found to make bouts of rhythmic ‘mastication-like’ noises that were not associated with ingestive feeding events. On average, these bouts consisted of 9.16 ‘mastications’, at an average rate of 1.21 ‘mastications’ per second, and occurred 53.3 times throughout a 24-h period. Furthermore, bouts were usually preceded by, and always followed by, a series of ‘creaky’, guttural noises that were interpreted as regurgitation and re-swallowing, respectively. Merycism may allow koalas to periodically re-masticate gastric digesta, while in a resting position, and thus potentially save energy and increase the extent of food preparation. Consequently, merycism may contribute to the koala's ability to consume a high fibre, poor quality diet.

Annual local survival of the garden dormouse Elyomis quercinus, a small, hibernating rodent, was studied by Cormack–Jolly–Seber models. The survival rates differed significantly between the 4 years of the study; the average rate was 0.38 (95% confidence interval: 0.25–0.52). Survival rates were not significantly different between sexes. Because all garden dormice were captured after weaning, pre-weaning survival could not be estimated. After weaning, the annual survival rates did not differ between age cohorts. In order to find out which phases within the annual cycle were more prone to mortality, survival was studied on a bimonthly scale as well. Survival during hibernation was estimated to be close to unity, while survival during the active phase of life in summer was considerably lower. The winter temperatures of the study years were similar to the long-year average; thus garden dormice were well adapted to these average conditions. Although hibernation is energetically challenging, it is not necessarily accompanied by increased mortality, as found in other studies focusing on survival during hibernation.

In this study the predation and fish prey selection of otters Lutra lutra L. living by eutrophic fish ponds on agricultural land and in a protected area of temperate climate in Hungary were investigated. The correlations between fish in the diet of the otters (by spraint analysis involved 1942 and 1280 samples for the two habitats) and the fish stock available (by harvest and sample fishing) were generally close. Prey selection was significantly related to selected species of a particular size range (P<0.01). The preference calculations were performed with Ivlev's index of preference (Ei, minimum −1, maximum +1). Regardless of species, the otters avoided (Ei=−0.51) fish heavier than 1000 g, with a preference for individuals weighing between 500 and 1000 g (Ei=0.79). No substantial or clear preference was observed in the weight range below 500 g (Ei=−0.02–0.38). The preference for fish in accordance with their characteristic sites of occurrence within the body of water was also significant (P<0.01). They avoided fish living primarily in open water (Ei=−0.64) and to a lesser degree those occurring near the pond bed (Ei=−0.22). They favoured fish inhabiting the area with a covering of aquatic plants (Ei=0.46), and showed a preference to a lesser degree for fish living in the shallow littoral regions (Ei=0.14). With the cessation of fish farming and the effect of the drastic changes which occurred in the vegetation, the otters fed substantially on the stock of alternative sources of prey such as amphibians and water insects as well as terrestrial animals, and at such times, depending on season, fish became a secondary source of prey.

By examining the morphological basis of force generation in the chelae (claws) of both molluscivorous and non-molluscivorous crabs, it is possible to understand better the difference between general crab claw design and the morphology associated with durophagy. This comparative study investigates the morphology underlying claw force production and intraspecific claw dimorphism in six brachyuran crabs: Callinectes sapidus (Portunidae), Libinia emarginata (Majidae), Ocypode quadrata (Ocypodidae), Menippe mercenaria (Xanthidae), Panopeus herbstii (Xanthidae), and P. obesus (Xanthidae). The crushers of the three molluscivorous xanthids consistently proved to be morphologically ‘strong,’ having largest mechanical advantages (MAs), mean angles of pinnation (MAPs), and physiological cross-sectional areas (PCSAs). However, some patterns of variation (e.g. low MA in C. sapidus, indistinguishable force generation potential in the xanthids) suggested that a quantitative assessment of occlusion and dentition is needed to understand fully the relationship between force generation and diet. Interspecific differences in force generation potential seemed mainly to be a function of differences in chela closer muscle cross-sectional area, due to a sixfold variation in apodeme area. Intraspecific dimorphism was generally defined by tall crushers with long in-levers, though O. quadrata exhibited an extreme dimorphism suggesting that factors unrelated to a speed–strength dichotomy (e.g. sexual selection) have shaped dimorphism of that species. It is concluded here that: (1) the majority of interspecific claw strength variation is a function of closer muscle cross-sectional area; (2) variation in claw morphology related to force production and transmission does have some relation to hardness of diet; (3) claw dimorphism in many species does seem to be related to strength and speed trade-offs; (4) factors besides molluscivory must be considered to understand claw evolution fully; (5) a quantitative assessment of force distribution, lacking in the literature, is essential for a more complete understanding of the relationship between claw design and ecological function.

Tardigrades have achieved a widespread reputation for an ability to survive more than a century in an inactive, ametabolic state called cryptobiosis. However, a closer look at the empirical evidence provides little support for the claim that tardigrades are capable of century-long survival. Instead, current evidence suggests that a decade may more realistically represent the upper limit of cryptobiotic survival in the most resistant tardigrades.

For the first time, an attempt has been made to quantify the effect of a copepod parasite (Ergasilus bengalensis) on the respiratory efficiency of the gills of a riverine catfish (Wallago attu) using an important parameter – the diffusing capacity. In addition, scanning electron microscopy has been used to demonstrate the effect of a monogeneid fluke on the gill lamellae of this catfish. The anchorage of E. bengalensis towards the leading edge of the interlamellar channels (pores) will affect laminar flow of water through the gill sieve. About 35% of the water flow (1.23×10−3 cm3/s) and lamellar area (15.41 mm2) of an infected gill filament (4.46 mm) is affected by the copepod parasite (1.59 mm). Other effects of the monogeneid flukes on the catfish included fusion of the tips of gill filaments and distortion of lamellar epithelium. Parasite-induced changes in the branchial organization are discussed in relation to oxygen uptake efficiency of the gills of the catfish.

The diet of the short-toed eagle (Circaetus gallicus) was studied during the breeding season by analysing pellets and remains generated by adults and nestlings. The raptor proved to be a specialist feeder, as snake prey comprised almost 95% of the diet, in both frequency and biomass. We gathered information on prey availability and prey size availability (1499 specimens of nine different species) by searching for snakes in the study area. Regressions of vertebra centrum length and dorsal-scale length on snout–vent length (SVL) of the snakes were used to calculate prey size. The taxonomic diet composition differed depending on the sample analysed – remains or pellets – but we failed to find between-year diet differences. Most of the snakes identified (140 out of 141) belonged to only three species, Malpolon monspessulanus, Elaphe scalaris, and Coluber hippocrepis. Other prey included Lacerta lepida, Natrix maura, Bufo bufo, and Alectoris rufa, and many secondary prey (prey from stomach of the prey) were also detected in the pellets. The three main prey species were consumed according to their availability in the study area, but the eagles selected on the basis of prey size. Large snakes within 700–1000 mm SVL were positively selected, whereas snakes under 600 mm SVL were negatively selected. Adult eagles consumed the same prey species as those carried to the nest to feed their single nestling, although prey given to nestlings proved larger in size and biomass, suggesting that adults consumed the smallest prey, reserving the largest for nestlings.