The breeding site characteristics of the smooth newt (Triturus vulgaris) and the common frog (Rana temporaria) have been investigated in the Republic of Ireland and in Northern Ireland. A total of 278 waterbodies and their surrounding terrestrial habitats were examined in 60 National Grid 10-km squares across the island: 33 habitat parameters were recorded. Discriminant function analyses were calculated which correctly classified 88.46% and 87.5% of the sites for the newt and frog, respectively. These analyses identified the terrestrial and aquatic habitat variables which were important in discriminating between the sites which were used and unused by each of the species. Terrestrial habitat factors, particularly the availability of terrestrial refugia, were found to be especially important in determining the suitability of the breeding sites for both species.

Data are presented on the demography and reproductive success of cheetahs (Acinonyx jubatus) living on the Serengeti Plains, Tanzania over a 25-year period. Average age at independence was 17.1 months, females gave birth to their first litter at approximately 2.4 years old, interbirth interval was 20.1 months, and average litter size at independence was 2.1 cubs. Females who survived to independence lived on average 6.2 years while minimum male average longevity was 2.8 years for those born in the study area and 5.3 years for immigrants, with a large proportion of males dispersing out of the Plains population. Females produced on average only 1.7 cubs to independence in their entire lifetime and their average reproductive rates were 0.36 cubs per year or 0.17 litters per year to independence. Variance in lifetime reproductive success in the cheetah is similar to that of other mammals.

No significant negative correlations were found between adult cheetah population size and numbers of cubs reaching independence, implying that the Plains population had not reached carrying capacity. Annual numbers of adult female cheetahs only were correlated with rainfall. Adult female cheetah numbers were not correlated with adult female lion numbers on the Plains, however, reproductive rates of cheetahs were negatively correlated with the presence of lions while cheetahs had cubs. Moreover, cheetah reproductive success was lower during the period of high lion abundance (1980-1994) than during the earlier period of relatively few lions (1969-1979). Litter size at independence dropped from 2.5 to 2.0, lifetime reproductive success declined from 2.1 to 1.6 cubs reared to independence, and the reproductive rate (cubs/year) decreased from 0.42 to 0.36 from the earlier to the later period.

Cheetah reproductive success showed little association with the presence of Thomson's gazelle at sightings except for a negative correlation between large numbers of gazelle (200±500) and reproductive success possibly because hunting success decreases with increasing prey herd size, or because cheetahs always lose in direct competition with other predators which are attracted to large congregations of prey. In addition, cheetah reproductive success was negatively correlated with the presence of Grant's gazelles (11 or more) perhaps because Grant's gazelles were more likely to occur consistently in dry areas.

Crytomys damarensis is a eusocial subterranean rodent occurring in colonies in which a sole reproductive female and one to two males are involved in procreation; the remaining colony members are non-reproductive. Within each sex the reproductive animals are usually the largest and most dominant animals.

The dominance hierarchy of a young colony consisting of a founding reproductive pair of genetically unrelated animals and the first three successive litters, comprising 12 offspring, from this pair had a non-linear dominance hierarchy, h = 0.32. Dominance was found to be correlated positively to body mass as well as to the age of the animal. A subsequent study, which followed the incorporation of two subsequent litters and growth of the first three litters, and comprised 15 offspring, revealed that the dominance hierarchy had attained linearity, h = 0.9. Dominance was again positively correlated with the age and body mass of respective colony members. In both studies there was no clear relationship between dominance and sex within the colony.

The relationship between body mass and burrow-maintenance activity revealed that frequent workers in the colony had a greater mean body mass than infrequent workers. It is suggested that in establishing colonies, the older, stronger and hence larger animals may constitute the initial workforce. In addition the colony exhibits frequency-related work determination into frequent and infrequent workers. Gender was found to play no role in the frequency of work associated with burrow maintenance.

The social organization and temporal changes with recruitment are discussed in the light of events occurring in the field.

The population biology of Paradistomum orientalis, a dicrocoeliid trematode occurring in the gall bladder of the garden lizard Calotes versicolor, was investigated during 1991-1993. The prevalence and abundance of the fluke were high throughout the year and demonstrated no seasonal fluctuations. The maturation cycle of the fluke followed an annual pattern. The recruitment of the fluke was restricted to the period September to February, with a peak during September. Mature flukes occurred throughout the year, facilitating continuous release of eggs into the macroenvironment. Rainfall plays a major role in governing the maturation cycle, by regulating the population density of the snail host and the feeding activity of the definitive host. The frequency distribution of the fluke followed the overdispersion pattern, fitting the negative binomial model. There is no evidence for the existence of parasite-induced host mortality. On the other hand, competition for space and nutritive resources under crowded conditions serves as a major regulatory force and is the key factor responsible for maintaining the equilibrium of parasite densities during different months. The infrapopulation of the fluke remained stable over several years.

Dragline use by an orb web spider (Nephila clavipes) was analysed by observing both intact spiders and those prevented from producing a dragline. The behaviours observed were those associated with returning to the web hub and prey capture. Upon returning to the hub, spiders resume the resting position by rotating within the hub, producing several new dragline attachment points during the rotation. The importance of the spider's use of the dragline was made clear by preventing experimental animals from producing the dragline. During resting, the permanent dragline-to-web attachment enabled the spider to maintain the correct posture. Prey capture behaviour was adversely affected in spiders prevented from using the dragline: without a dragline, all relevant components of the behaviour required more time to perform, and movements within the web (e.g. toward prey and back toward the hub) were directed less accurately. The benefit of the dragline to the spider, in terms of safety, time, energy and reduced exposure to predators, is likely to be significant.

The demography of red and grey squirrels was studied by live-trapping and radio-tagging at 14 deciduous and conifer sites in southern Britain and at eight conifer sites for one year in northern England. Densities and productivity correlated with tree seed crops for both squirrel species in deciduous and conifer habitats. Productivity was reduced by high density of full-grown squirrels relative to seed abundance. In oak-hazel woods, demography of grey squirrels correlated with abundance of acorns but not of hazel-nuts, whereas density and productivity of red squirrels correlated with hazel-nut abundance. Correlations of female density and productivity with pine-cone crops did not differ between red and grey squirrels. Predators ate many radio-tagged grey squirrels in conifers, and annual survival was only 50% compared with 80-82% for both species in other habitats. Grey squirrel populations in southern conifer sites were sustained by immigration, and at northern sites female density correlated with oak abundance within 500m. Failure to exploit acorn crops puts red squirrels at a competitive disadvantage in deciduous woodland. Red squirrels had higher survival than grey squirrels in conifers, which may give them an advantage in that habitat, but could also have been explained by a lack of predators on their island study site.

Although sex biases in natal dispersal are well known among birds and mammals, female-biased dispersal in polygynous mammals is rare. North American porcupines are polygynous and recent evidence suggests that natal dispersal in this species may be female-biased. We used data on disappearances, immigration, and reproductive behaviours to characterize natal dispersal and examine the extent to which inbreeding avoidance may motivate natal dispersal in porcupines. We predicted that, if female porcupines were the predominant dispersers, rates of disappearance and immigration would be higher for females than for males. Also, if females disperse to avoid mating with fathers, then the mean age of females at first conception should be less than the mean residence time of adult males. Population data suggested that natal dispersal was female-biased because a higher proportion of females (31%) disappeared than males (11%), and 78% of 18 immigrants observed in the population were females. Data on pregnancies indicated that female age at first conception ([ape ]25 months) was less than the mean residence time of adult males ([ape ]26 months), suggesting that female porcupines may disperse to avoid incestuous matings with fathers. Little is known regarding potential resource competition between mothers and offspring, or on how philopatric males avoid mating with their mothers. Additional data are needed in these areas to interpret dispersal tendencies in porcupines.

Timing of birth was determined for 292 roe deer (Capreolus capreolus) fawns belonging to 146 litters on an island in central Norway between 1991 and 1994, and for 33 fawns belonging to 19 litters from an inland site from 1995 to 1997. On the island site there was no significant variation between years in the mean date of birth, 22 May, nor was there any significant effect of dam age, fawn sex, or litter size. Individual does tended to give birth close to the same date in consecutive years. Mean birth date at the inland site was 5 June. The births showed a relatively high degree of synchrony with 80% occurring within 26 days and 24 days at the island and inland sites, respectively. Copulation dates were much more synchronized than birth dates on the island site. Gestation length averaged 301 days, although individuals varied by up to 26 days. When comparing published data from European populations, there appears to be extensive variation in timing of birth, while birth synchrony is very conservative. There appears to be little possible anti-predator benefit for roe deer in any pattern of birth synchrony. Because of their high post-natal investment and large litter size, we hypothesize that roe deer are constrained to give birth close to the peak of forage productivity.

This study addresses the question of how three species of flightless feather lice (Phthiraptera) specific to a brood parasitic bird, the common cuckoo (Cuculus canorus), are transmitted from one cuckoo generation to the next in the absence of any direct contact between parent and young. None of 21 cuckoo nestlings examined shortly before fledging carried cuckoo lice; nor were any lice found in 19 nests in which cuckoos had laid. Cuckoos returning to Japan for their first breeding season were as likely to be lousy as, and carried similar louse loads to, older birds. These field observations are consistent with data arising from examination of museum skins from European breeding areas and from African wintering areas, and it is concluded that cuckoos acquire their lice between leaving the nest in summer and returning to the breeding grounds the following spring. This acquisition probably occurs via direct body-to-body contact between cuckoos, a supposition bolstered by some observations.

Hair morphology has been studied and applied in several subjects, such as food quality control, archaeology, criminology, and ecology. Although medullar and scale patterns of hair structure are well known for a variety of mammal species, the effects of hazardous conditions on the internal and external morphology of hair are not known. In the present work, white-eared opossum (Didelphis albiventris) hairs were submitted to taxidermy, digestion, and putrefaction processes, and afterwards their structure was compared to control hairs, under the scanning electron microscope and light microscope. The results obtained indicate that the processes tested do not cause damage to the medullar and scale patterns of the opossum's hairs. In conclusion, based on the experiments with D. albiventris hairs, it is possible to compare hairs from museum collections or freshly collected hairs to hairs found in scats, gut contents, pellets, or other sources.

Fourteen radio-tagged red squirrels were released in pine woodland containing grey squirrels. Movements of the squirrels were related to the tree species of the donor site. Survival after release was lower than for the grey squirrels: of 11 red squirrels that survived at least a week, only three survived more than three months and none for four months. More than half were eaten or cached by predators, mainly foxes; an experiment with grey squirrel carcasses indicated that they had been killed, not scavenged after death. Hypertrophied adrenals, disease and loss of weight indicated stress as another factor in the deaths. Data on overlap of core ranges, and reluctance of red squirrels to enter traps used by grey squirrels in the mixed population, indicated interference competition between the two species, with grey squirrels possibly dominant. We recommend: (i) that care should be taken to release translocated animals in similar habitat to their origin; (ii) that grey squirrels should be excluded from future release areas until red squirrels have settled and, before biodiversity is reduced by landscape management for red squirrels; (iii) more research to determine whether interactions with grey squirrels or differential predation will ultimately displace red squirrels in conifers.

A radio-tracking study of two adjacent social groups of red foxes was conducted in a suburban residential district of greater Toronto from late July through December 1990. This was the first radio-tracking study of red foxes living completely within a large metropolitan centre in North America. The groups had non-overlapping home ranges and included both breeding and non-breeding adult females. Mean group home range size was 52 ha, toward the small end of home ranges documented for the species, and distances travelled nightly by adults of both sexes ranged from 2-20 km. The home ranges of both groups were primarily located in a bushy ravine containing golf courses and park land, but individual foxes readily utilized areas of low-density housing characterized by large, well-vegetated lots. However, the foxes avoided adjacent medium-density housing areas, indicating that this population may not be as habituated to urban life as some populations described from Great Britain and mainland Europe. Because of their constant proximity to, and frequent use of, some residential habitat types, these foxes have ample opportunity to transmit diseases such as rabies to domestic pets and humans in the vicinity.

Circadian rhythms of metabolic rate and body temperature were measured in groups of huddling and solitary red-billed woodhoopoes (Phoeniculus purpureus) as a function of ambient temperature. Basal metabolic rates were 30-60% lower than those of similar-sized birds of other species. As a consequence, circadian amplitudes of Tb and VO2 fluctuation between the rest and activity phases of non-huddling birds were also larger than expected. Circadian rhythms of metabolism save huddling and non-huddling woodhoopoes 19-34% of their potential daily energy expenditure. Birds huddling in groups conserved 12-29% of the daily energy expenditure of non-huddling birds at ambient temperatures of 20°C and below. However, at 30°C huddling birds used c. 12% more energy than non-huddling birds. The various avenues of energy conservation employed by woodhoopoes are suggested to be beneficial in: a) augmenting the proximate benefits of cooperative breeding; and b) optimizing fitness in the drought-prone sub-Saharan savannahs which are heavily influenced by the El Niño Southern Oscillations.

Male Teleogryllus oceanicus prefer to call from refuges and from these protected sites produce signals that contain more trill elements than produced by males calling without the protection of refuges. We tested the vulnerability of male crickets to predation from two species of gleaning bats, Nyctophilus major and N. geoffroyi. Crickets called from the floor of darkened fly-ways where bats preyed on calling rather than silent males. Both species of bat used passive listening to locate their prey rather than echolocation. Those crickets calling from refuges avoided predation. By counting the number of passes each bat made over paired speakers emitting different digitized songs, we tested the bat's preference for different call elements or the total number of sound elements in the song per unit time. When the total number of sound elements of each signal was balanced, bats preferred trills to chirps, and when call length differed, bats preferred those signals with more total sound elements. We discuss the possibility that predation by bats is a form of counter-selection on calling in T. oceanicus.

The kidneys of Anna's hummingbird (Calypte anna) differ in several significant ways from those of other birds that have been examined. The kidneys of this nectarivore contain very little medullary tissue; 90% of the total volume of the kidneys is cortical tissue, with medulla accounting for only an additional 2%. More than 99% of the nephrons are the so-called ‘reptilian type’), which lack the loop of Henle. The few looped (‘mammalian type’) nephrons are incorporated into only a few medullary cones per kidney. The loopless nephrons are similar to those of other birds. However, the looped nephrons differ in that they lack the thin descending limb of the loop of Henle, which is found in other birds and is thought to play an important role in the countercurrent multiplier system in the avian kidney. Instead, the cells of the nephron segment following the pars recta of the proximal tubule resemble those of the thick ascending limb, with the large populations of mitochondria that are typical of transporting epithelia and no reduction in cell height. The absence of a descending thin limb in Anna's hummingbird is not necessarily a correlate of the hummingbird's liquid diet, because thin limbs have been documented in the kidneys of two other hummingbird species, the rufous hummingbird (Selasphorus rufus) and the broad-tailed hummingbird (Selasphorus platycercus). The functional correlates of the unique renal morphology in Anna's hummingbird warrant further study.

The distribution of the bush-dwelling snail Theba pisana (Helicidae) in Israel is restricted to the coastal plain. It is known as an annual semelparous species, but recent studies revealed that part of the population has a biennial life cycle.

The present study examined the water economy and resistance to desiccation throughout the life cycle under natural conditions in the field, and by exposing samples of various size (age) groups to three weeks of laboratory desiccation during various seasons.

We found that resistance to desiccation in Theba pisana is age-dependent as young snails lost more water than adults during desiccation. In general, high rates of water loss during desiccation were noted in growing snails during winter and spring, and low rates were recorded during the summer aestivation in all age groups. A small part of the natural population ceased growing and entered an early aestivation, thereby avoiding the otherwise high rates of water loss.

We conclude that resistance to desiccation is entrained in the annual life cycle of T. pisana and that survival under natural desiccating conditions depends on the maturation, and on the ontogenetic development of the water preserving mechanisms. The age-dependent water economy of the snail dictates the timing of aestivation and the establishment of a new set-point which is reflected in the clustering behaviour, secretion of a calcareous epiphragm, and a selective compartmentalization of body fluids.

It is demonstrated that cross-fostering is a practical way of improving the rate of increase of a rare species in captivity. Two adult Bettongia tropica were captured in northern Queensland and housed in captivity in Adelaide, South Australia. Eleven pouch young born in captivity to the wild-caught B. tropica were transferred at 20 days old or older to B. penicillata foster mothers and nine were reared successfully. Of a further 10 young not fostered, six were reared by the wild-caught mother. Fostering allowed the wild-caught female to produce surviving young nearly twice as frequently as if she had reared them in her pouch.

Sexual maturity occurred at 246-523 days (x[bar] = 407.2 ± 59.9 days) in 4 males and at 185-429 days (x[bar] = 300.5 ± 26.0 days) in 11 females. Breeding continues throughout the year and females undergo embryonic diapause whilst supporting a pouch young. The female reproductive system is remarkable for its relatively long urethra and lateral vaginae and consequently short urogenital sinus. The male reproductive system is unremarkable, having a carrot-shaped prostate gland and three pairs of Cowper's glands, as do many other macropodoid species. Two pairs of paracloacal glands are found in males and females.

The condition factor and fecundity of the translocated rock-dwelling cichlid fish, Cynotilapia afra, Pseudotropheus callainos, and Pseudotropheus tropheops ‘red cheek’ at Thumbi West Island, southern Lake Malawi, were compared with those at their sites of origin, in the north of the lake. The guiding hypothesis was that these species, having originated from a region of the lake which is generally poor in nutrients, and been introduced to an area richer in nutrients, would be in better condition and more fecund there than at their sites of origin. That seemed to be the case. P. callainos and P. tropheops ‘red cheek’ had significantly higher condition factors and fecundity indices at Thumbi West Island than at their sites of origin. However, both condition factor and fecundity of all the species studied fluctuated seasonally. The major peaks in condition factor coincided with either the wind-induced lake upwelling from June to August, or the rains. Major peaks in fecundity occurred at the end of the rainy season, between February and April, or at the end of the upwelling period between September and October. The translocated species began to breed at a smaller size at their sites of origin in the north than at Thumbi West Island, probably as an adaptive response to a poor nutrient regime in the north.

The increase in population of some translocated species can be partly attributed to their improved condition and fecundity due to enhanced nutrient availability at the site where they have been introduced. This may have negative implications for the native taxa, more particularly as competition for breeding space is rife among the rock-dwelling cichlids of Lake Malawi.

Two large (dorsal mantle length 42.5 and 47.5 cm), mated spent females of circum-Antarctic bathypelagic cranchiid squid Galiteuthis glacialis were caught early in March 1992 at the surface of the ice hole in the western Weddell Sea over depths 1915-1920 m by the team of the U.S.A.-Russian Ice Station Weddell-I. The structure of the reproductive system of adult females is described for the first time in detail.

Both were gelatinous, devoid of tentacles, with empty or almost empty stomachs. The empty spermatangia (sperm reservoirs of spermatophores) 30-35 mm in length were distributed in the mantle tissues parallel to the mantle surface and to each other in the dorso-anterior part of the mantle: 13 in one female, parallel to the body axis, and 20 in the other, parallel (13) or perpendicular (7) to the body axis. In the latter case, they represented probably two mating events. The spermatangia lay nearer to the inner than the outer mantle side and opened by a round window on the inner side; the skin with chromatophores above them remained intact. The spermatozoa had one flagellum and rod-like heads, length 5.0-5.3 μm, width 1.2-1.5 μm. The most characteristic features are: a very simple type of blood vessel branching making each micro-gonad currant-like, not grape-like; a very compact disposition of oviducal, nidamental glands and gill, forming a united complex located on both sides of the mantle cavity; and an ovary connected by mesentery along all its length with the continuation of the stomach from the caecum to the end of the gastrogenital ligament. Only immature degenerating trophoplasmatic oocytes, length 0.9-1.4, av. 1.0-1.2 mm, were contained in ovaries; only one mature egg (length 3.3 mm, width 2.4-2.5 mm) was found in each female. The absence of oocytes <0.9 mm and 1.5-3.2 mm indicates that the maturation of oocytes proceeds rather synchronously, one large portion of eggs (some tens of thousands) matures in a short time while others degenerate. The residual fecundity is assessed to be approximately 20,000 eggs.

It is hypothesized that mating occurs shortly before spawning and that mature males do not undergo gelatinous degeneration and do not lose tentacles. Spermatophores are placed on the inner side of the female's mantle with the aid of the male's tentacles and/or arms (less probably by the penis), but the exact mode of implantation is unclear. Spawning probably occurs at depths of adult habitat (approx. 500±2500m), may be multiportional but short; the exhausted female loses neutral buoyancy, rises to the surface and dies. Rising to the surface after spawning is a common feature of females of many meso- and bathypelagic squids undergoing gelatinous degeneration during maturation (Onychoteuthidae, Gonatidae, Histio-teuthidae, Cranchiidae, etc.) and may explain the common occurrence of large deep-water squids in the stomachs of seabirds, including those incapable of diving, and marine mammals.