bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation of adult body size of the tortoise Testudo hermanni in Greece: proximate and ultimate causes
Authors: Willemsen R. E. , Hailey A.
Published: February 2006

Seventeen populations of T. hermanni in Greece differed substantially in mean adult body size, over a range of about one and a half times in length and three times in mass. Females were the larger sex in all populations; the degree of sexual size dimorphism did not vary with mean body size. The proximate cause of the variation of body size among populations was differences in the duration of growth, rather than egg or hatchling size or the growth rates of juveniles. The age at maturity (α) increased with body size in the 17 populations, while the Bertalanffy growth constant (k) decreased with body size. The quantities αM and M/k (where M is the instantaneous mortality rate) were invariant with body size, suggesting that differences between populations were adaptive rather than the result of short‐term disturbance. Body size was greater in cooler areas, and increased with both latitude and altitude. This pattern is opposite to that found in most ectotherms (the reverse Bergmann's rule), and to that which occurs between tortoise species. Several hypotheses about the possible ultimate causes of variation of body size were rejected, including adaptation to long‐term habitat disturbance (land use), character displacement, social factors, energetics, thermoregulation, r‐K selection, the length of the season available for incubation, or differences in juvenile mortality. The most likely ultimate cause of size variation between sites is differences in adult mortality, the correlation with environmental temperature being through the frequency of fires.
Winter activity of a population of greater horseshoe bats (Rhinolophus ferrumequinum)
Authors: Park Kirsty J. , Jones Gareth , Ransome Roger D.
Published: February 2006

Activity patterns of greater horseshoe bats Rhinolophus ferrumequinum were investigated at caves in Cheddar (south‐west England) during the hibernation season. An ultrasound detector and datalogger were used to monitor and record the number of echolocation calls in a single cave. Activity of R. ferrumequinum remained largely nocturnal throughout winter, and the mean time of activity over 24 h was 88 to 369 min after sunset. There was an increase in diurnal activity from late May to early June, probably because bats remained active after foraging at dawn towards the end of the hibernation season. Visits to the cave did not increase bat activity. Cave air temperature reflected external climatic temperature, although there was variation in cave temperature and its range within and among caves. Individual R. ferrumequinum are usually dispersed in caves in regions where temperature fluctuations correlate with climatic variations in temperature. There was a positive correlation between the number of daily bat passes monitored by the bat detector and datalogger (= daily activity) and cave temperature. Nocturnal activity may be sometimes associated with winter feeding. Neither date nor barometric pressure had a significant effect on daily activity. Activity patterns largely reflected the findings from individual R. ferrumequinum studied by telemetry (Park, 1998), in that bat activity increased with cave and climatic temperatures, and the temporal pattern of activity remained consistently nocturnal throughout winter, starting at dusk.
Habitat selection by barbastelle bats (Barbastella barbastellus) in the Swiss Alps (Valais)
Authors: Sierro A.
Published: February 2006

Recent faecal analyses have shown that barbastelle bats Barbastella barbastellus are highly specialized moth predators. The predominance of moths (> 99% by volume) in their diet both in wooded areas of the Swiss Alps and in denuded steppe areas of Central Asia further suggests that this narrow diet does not stem from a highly specialized habitat selection, but merely from peculiar species‐specific foraging constraints. Non‐opportunistic predators relying on a few prey types must find areas providing their basic prey in abundance. Using radiotracking, habitat selection was investigated in a population of barbastelle bats inhabiting xeric forests in the Swiss Alps. In particular, I tested the prediction that the biologically most productive areas within the forest are exploited in priority. Eleven individuals were radiotracked from June through to October 1992, and in June 1993. The home range (59 ha) of the overall radiotracked population was divided in 236 cell units of 0.25 ha each. Within each cell, habitat and vegetation structure was described using 19 environmental variables. Habitat selection by the bats was investigated through stepwise regression analysis, which retained 11 variables showing a significant positive relationship with habitat use. The four variables accounting for 31% of the overall variance were: litter thickness, percentage of shrub layer cover, percentage of pine tree cover, and circumference of oak trunks. The results showed a clear preference by barbastelles bats for richly structured forests, and an avoidance of open woodland on stony outcrops and rocky slopes. This confirms that the biologically most productive parts of the forest were exploited in priority.
The food supply of Arabian oryx (Oryx leucoryx) in the desert of Oman
Authors: Spalton J. A.
Published: February 2006

The crude protein content, water content and in vitro digestibility of grasses in the diet of the Arabian oryx Oryx leucoryx were investigated. In the main food species, Stipagrostis spp., levels of crude protein, water content and digestibility were generally highest in the flower component while in other species, leaf was the best quality food. Crude protein content, water content and digestibility were highly correlated and all declined exponentially following rainfall. Levels remained comparatively high, even during extended drought, largely because fog and dew‐fall enabled some plants to continue to produce green leaf material. The crude protein content of rumen material from oryx that died during drought was negatively correlated with time since rainfall. Estimates of dietary crude protein derived from the protein content of rumen material were comparable to those predicted for available grass forage. The results are discussed in the context of the food and water requirements of oryx. It is suggested that during drought some grasses continue to be a source of adequate crude protein and water and of sufficient digestibility but that levels are close to minimum maintenance requirements. This and the decreasing biomass of available forage of sufficient quality lead to condition loss and death, particularly of the most vulnerable animals. Crude protein may become limiting sooner than does water.
Age‐related participation in allosuckling by nursing warthogs (Phacochoerus africanus)
Authors: Plesner Jensen S. , Siefert L. , Okori J. J. L. , Clutton‐Brock T. H.
Published: February 2006

This paper examines the distribution of non‐offspring nursing or ‘allosuckling’ in warthogs Phacochoerus africanus. Of the 16 breeding groups studied, 11 contained two or more nursing females. Allosuckling occurred in six of these groups (55%). The number of juveniles per nursing female was lower for groups with allosuckling, although juvenile mortality was not measurably affected by either allosuckling, group size or the number of females in a group. Time spent drinking was longer for juveniles in smaller litters but was not influenced by allosuckling or juvenile age. Longer intervals between the females' nursing bouts resulted in longer drinking bouts for the juveniles, but there was no correlation with inter‐meal intervals. The proportion of successful sucking bouts increased with juvenile age. This success rate was greater in groups without allosuckling, suggesting a better co‐ordination between mother and offspring. Females appeared able to distinguish between juveniles and to nurse selectively. Four‐ to 5‐year‐old females nursed fewer juveniles than did older or younger females in their groups and were thus less likely to be donors.
Diet of tawny owls (Strix aluco) in relation to field vole (Microtus agrestis) abundance in a conifer forest in northern England
Authors: Petty S. J.
Published: February 2006

The diet of tawny owls Strix aluco was determined from pellets and prey items in owl nests in Kielder Forest, a planted spruce forest in northern England. Field voles Microtus agrestis were their most important food, and formed the highest proportion of tawny owl diet in winter and early spring. Common shrews Sorex araneus, common frogs Rana temporaria and birds were taken more frequently in late spring and summer. Clear cuts, areas from which timber had been felled at the end of the rotation, provided the main field vole habitat in the forest and remained suitable for voles for 10–15 years after re‐planting. Field vole abundance was measured three times a year on numerous clear cuts throughout the study area using a vole sign index based on fresh grass clippings in runways. Tawny owls responded functionally to the 3 to 4‐year cycles of field vole abundance. In years when voles were scarce, adult owls took more common shrews and common frogs, as determined from pellet analysis. In contrast, more bird prey was fed to nestlings when field voles were scarce, as determined from prey items in nests. The proportions of the main prey in nests changed over a 19‐year period. More bank voles Clethrionomys glareolus and wood mice Apodemus sylvaticus occurred in every year after 1992 than in any year before this. Numbers of wood mice in owl nests increased significantly throughout the study period, whereas bank vole numbers exhibited non‐cyclic, multi‐annual fluctuations that were unrelated to field vole cycles. It is argued that fluctuations in rodent prey reflected changes in rodent guilds in the study area; reasons for this are discussed. This is the first study of tawny owl diet in spruce forests in Britain and highlights the value of such large‐scale dynamic habitats for rodent populations and their predators.
Morphology and phylogenetic implications of oesophageal modifications in the Limnodriloidinae (Oligochaeta, Tubificidae)
Authors: Gustavsson Lena M. , Erséus Christer
Published: February 2006

Two features have been considered apomorphic for the subfamily Limnodriloidinae (Tubificidae): the lobed prostate glands, which are broadly attached to prostatic pads inside the atrial ampullae, and the ‘modified oesophagus’ in segment IX. The homology of the modified oesophagus may be questioned, as it is not of the same kind in all taxa. In Limnodriloides, Smithsonidrilus, and Tectidrilus, there is a pair of diverticula, whereas in Thalassodrilides, Parakaketio, and Doliodrilus, the oesophagus is dilated to form a barrel‐shaped portion. In a few species of Limnodriloides lacking diverticula, a short part of the corresponding oesophagus is swollen. A scrutiny of these features shows that they are morphologically different in several aspects: the thickness and the structure of the epithelium, the granulation, the shape of the cells and the length of the modifications. Moreover, a regular, semi‐embedded blood plexus always occurs around the barrel‐shaped portion but rarely around the diverticula (if present, plexus irregular), and never around the swollen part of the oesophagus. These different types of modifications fail the similarity test and thus should be regarded as independently evolved structures and coded as different characters in a parsimony analysis. Species from other subfamilies within the Tubificidae were also morphologically investigated, and modifications of the alimentary canal were found in a few of them: Ainudrilus lutulentus, Heronidrilus bihamis, H. fastigatus (all Rhyacodrilinae) and Clitellio arenarius (Tubificinae). The modification in segment VIII of Heronidrilus spp. resembles the barrel‐shaped portion in, for example, Thalassodrilides, and should primarily be coded as the same character in a congruence test of homology.
Food habits of the long‐nosed snake (Rhinocheilus lecontei), a ‘specialist’ predator?
Authors: Rodríguez‐Robles Javier A. , Greene Harry W.
Published: February 2006

We explored predator specialization by examining dietary variation in the widespread North American long‐nosed snake, Rhinocheilus lecontei. We examined the stomach contents of more than 800 museum specimens, and supplemented our findings with published dietary records. Sixty‐six percent of 135 prey eaten by R. lecontei were lizards, 26% were mammals, and 7% were squamate eggs; teiid lizards of the genus Cnemidophorus comprised 72% (64 of 89) of all lizard prey. Ninety‐four percent of specimens with food contained a single item, and all 79 prey for which we determined direction of ingestion were swallowed head‐first. Among those specimens containing food, long‐nosed snakes from Mexico were significantly larger, and ate a higher percentage of mammals, than specimens from the United States. Larger R. lecontei sometimes fed on larger prey, and perhaps excluded smaller prey from their diet. To assess relative trophic niche breadth for R. lecontei, we compared the percentage of lizards and of Cnemidophorus in the diet of long‐nosed snakes with the percentage with which other terrestrial snakes consumed lizards as their modal prey, and with which these same snakes ate members of their preferred lizard prey genus. Although we uncovered no statistical basis for labelling R. lecontei a specialist, its diet may often be restricted to lizards and even to Cnemidophorus, and therefore recognizing long‐nosed snakes as specialist predators remains a subjective decision. Our study also demonstrates that quantitative natural history can place related species in a resource use continuum, and thereby can help to elucidate the evolutionary basis for specialization.
A second primitive marine snake: Pachyophis woodwardi from the Cretaceous of Bosnia‐Herzegovina
Authors: Lee M. S. Y. , Caldwell M. W. , Scanlon J. D.
Published: February 2006

The fossil of a second primitive snake from Cretaceous marine sediments is identified and redescribed: Pachyophis woodwardi Nopcsa. This snake was similar to Pachyrhachis in having pachyostotic vertebrae, a slender neck and a small head. However, Pachyophis differed from Pachyrhachis in being even more aquatically adapted: the mid‐dorsal vertebrae and ribs are more swollen (pachyostotic), the body was more laterally compressed, and the dentary contains more teeth. The hindlimb (well developed in Pachyrhachis) cannot be confirmed as present or absent in Pachyophis. A cladistic analysis demonstrates that Pachyophis and Pachyrhachis form a clade. This grouping, here termed the Pachyophiidae, forms the most basal group of snakes so far known and is the sister group to all other well‐known snakes.
Body size, and interactions between European and American mink (Mustela lutreola and M. vison) in Eastern Europe
Authors: Sidorovich V. , Kruuk H. , Macdonald D. W.
Published: February 2006

Body sizes of European mink (Mustela lutreola L.), polecat (M. putorius L.) and American mink (M. vison Schreber) were studied over a 10‐year period in an area of north‐eastern Belarus, before and after the invasion by American mink, and data are presented on interspecific interactions. On arrival in the study area American mink males were larger than males of European mink and polecat, and American mink females were larger than females of the other species. After arrival of the American mink its mean body size decreased, whilst the resident male and female European mink and female polecat increased as measured in absolute mass, length and relative mass. The observations suggest a strong character convergence most plausibly explained as a response to the invading exotic by the residents as well as in the invading species itself, whilst a divergence had been expected. There was no evidence to show whether these differences were genetically based. The body size data are consistent with the hypothesis that European mink, and to a lesser extent polecat, are responding to direct aggression from American mink (rather than merely competing for resources), with the smaller individual European mink being more likely to disappear first. We provide direct evidence for the aggressive nature of inter‐specific relations from observations using radio‐tracking: all observed inter‐specific interactions were aggressive, significantly more so than intraspecific encounters, causing the European mink to flee, and several left the study area altogether. Implications for niche theory and for conservation management are discussed.
Postnatal growth and age estimation in the Indian false vampire bat (Megaderma lyra)
Authors: Rajan K. Emmanuvel , Marimuthu G.
Published: February 2006

The Indian false vampire bat Megaderma lyra produces a single young under captive conditions, which is altricial at birth. Empirical growth curves were derived by measuring length of forearm, body mass and length of the total gap of the fourth metacarpal–phalangeal joint. Length of forearm and body mass followed a linear pattern of growth until day 28 and subsequently reached stability. The length of the total gap of the metacarpal–phalangeal joint initially showed a linear increase up to 4 days, followed by a linear decrease until 34 days when it closed. A quantitative method of estimation of age was derived from values of length of forearm and length of the total gap of the fourth metacarpal–phalangeal joint during the preflight (first 28 days) and postflight stages, respectively. Width of the 95% confidence level was ± 1.2 days at a mean length of forearm of 51.6 mm, and ± 0.07 days at a mean length of the total gap of the fourth metacarpal–phalangeal joint of 1.89 mm. Initiation of flight occurred 24 days after birth. At 28 days of age, young were able to forage on their own. There was no significant difference in the growth pattern of young held in captivity compared to that of young grown under natural conditions.
Use of the nutrients in bamboo by the red panda (Ailurus fulgens)
Authors: Wei Fuwen , Feng Zuojian , Wang Zuwang , Zhou Ang , Hu Jinchu
Published: February 2006

Nutrient use by the red panda Ailurus fulgens was measured in animals fed only on their natural bamboo Bashania spanostachya diet. The project was carried out at the field observation station of Yele Natural Reserve in Sichuan, China. Two‐week long trials were conducted at monthly intervals from May to November 1995. Results showed that dry matter digestibility differed significantly among seasons and between diets. Digestibilities of dry matter and key nutrients were high in summer–autumn, intermediate in spring and low in winter. Shoots were more easily digested than leaves and exhibited the highest digestibility. These variations were positively correlated with nutrient contents in bamboo. The results also indicated that the red panda poorly processed its bamboo food. This was demonstrated by the lower digestion coefficients of dry matter and nutrients, especially that of cell wall constituents. This implied that microbial digestion only played a minor role in its digestive strategy, similar to the giant panda Ailuropoda melanoleuca, another herbivorous carnivore. In addition, the transit of bamboo through the red panda gut was very rapid (2–4 h). In order to survive on this poor‐quality diet, it seems that the red panda has to select high‐quality items of bamboo such as tender leaves and shoots. These are ingested in large quantities (over 1.5 kg of fresh leaves and 4 kg of fresh shoots daily) that pass through the digestive tract fairly rapidly so as to maximize nutrient intake.
Diet choice and capture success of wild dog (Lycaon pictus) in Hluhluwe‐Umfolozi Park, South Africa
Authors: Krüger Sonja C. , Lawes Michael J. , Maddock Anthony H.
Published: February 2006

The small population of wild dog Lycaon pictus (n= 3 to 30) in Hluhluwe‐Umfolozi Park (HUP) has declined since 1992. The survival of dogs in HUP is dependent on the reintroduction of more dogs; however, wild dog reintroduction programmes are fraught with problems and many have failed. In this paper the diet and capture success of the wild dog pack in the Hluhluwe Section, and the influence of dietary considerations on the success of the future reintroduction of wild dogs in this reserve, are investigated. Diet choice was determined from scat analysis, personal observation and field staff records. Eight ungulate prey species were identified from scat analysis: nyala Tragelaphus angasi and impala Aepyceros melampus were the most abundant ungulate species in HUP and accounted for 77% of the diet. On the whole, wild dogs included prey types in the diet consistent with a rate‐maximizing foraging approach, although some prey were clearly taken opportunistically. The dogs preyed mostly on small‐ (> 25 kg) to medium‐sized (40–90 kg) prey, while the young of large (< 90 kg) prey species or scavenged carcasses supplemented the diet during the dry season. Adult nyala were taken more frequently than other age classes, but wild dog preyed on juvenile impala more than expected. Female prey were taken more frequently than males but selection did not differ from prey population sex ratios. Prey capture success was similar to that of previous studies from both open and densely wooded habitats and the wild dogs successfully caught 48% of all prey species pursued. Results suggest that wild dogs are quite capable of adapting both their diet choice and foraging technique to the dense vegetation in HUP. We conclude that prey type, prey availability and habitat constraints on prey capture success, will not affect the reintroduction of more wild dogs into HUP.
Grouping behaviour, tail‐biting behaviour and sexual dimorphism in the armadillo lizard (Cordylus cataphractus) from South Africa
Authors: Mouton P. le F. N. , Flemming A. F. , Kanga E. M.
Published: February 2006

Grouping behaviour, tail‐biting behaviour and sexual dimorphism were investigated in Cordylus cataphractus, a rock‐dwelling lizard from South Africa. Eighty‐five per cent of individuals collected during different seasons occurred in groups of two or more, which shows that grouping behaviour is a year‐round phenomenon in this species. Group size ranged from one to approximately 30. Groups smaller than nine individuals normally included only one adult male, but larger groups often had more than one. Sixty‐eight per cent of lone individuals were adult males. All individuals (n= 134) attempted to bite their tails and roll into a ball on collection. Cordylus cataphractus prefers horizontal crevices with an accompanying ledge on which animals can perch in close proximity to the crevice. Males apparently reach larger asymptotic body sizes than females and also have larger heads and longer tails. The higher incidence of scars among males suggests that sexual dimorphism could result from sexual selection, but sexual differences in scaling of head and tail dimensions, however, suggest that the dimorphism may be the result of differential energy allocation by females. Unlike most other Cordylus species which have female‐biased sex ratios, the ratio is close to one in C. cataphractus.
Identification of newts (Triturus sp.) and their hybrids using molecular methods
Authors: Beebee T. J. C. , Rowe G. , Arntzen J. W.
Published: February 2006

Identification of hybrids is important for the study of introgression between related species, but can be difficult when morphological differences between parental species are small. In the case of the newts Triturus vulgaris and T. helveticus, males are readily identifiable during the breeding season when secondary sexual characters are highly developed, but female dimorphism is always much less. Male hybrids with intermediate characters are therefore more likely to be detected than female ones. RAPD (random amplified polymorphic DNA) analysis of three putative newt hybrids and examples of the two parent species T. vulgaris and T. helveticus confirmed hybrid status in all three cases. The maternal parents of each hybrid were identified by amplification of mitochondrial cytochrome b and ATPase genes, including partial sequencing of the latter. One hybrid had a T. vulgaris mother while the other two had T. helveticus mothers. The PCR‐based methods therefore provided a quick and simple approach for identifying both hybrid status and parentage in crosses between these two urodele species. The RAPD technique should also prove useful for the identification of larvae, which are morphologically indistinguishable in T. vulgaris and T. helveticus.
A phylogeny of the European lizard genus Algyroides (Reptilia: Lacertidae) based on DNA sequences, with comments on the evolution of the group
Authors: Harris D. James , Arnold E. Nicholas , Thomas Richard H.
Published: February 2006

The four species of Algyroides Bibron & Bory, 1833 form part of the relatively plesiomorphic Palaearctic clade of lacertids comprising Lacerta and its allies. An estimate of phylogeny based on DNA sequence from parts of the 12S and 16S rRNA mitochondrial genes confirms the monophyly of the genus already suggested by several morphological features. The molecular data also indicates that relationships within the clade are: (A. nigropunctatus (A. moreoticus (A. fitzingeri, A. marchi))); this agrees with an estimate of phylogeny based on morphology that assumes the taxon ancestral to Alygroides was relatively robust in body form, and not strongly adapted to using crevices. Initial morphological evolution within Algyroides appears to involve adaptation to crypsis in woodland habitats. The most plesiomorphic form (A. nigropunctatus) is likely to have originally climbed extensively on tree boles and branches and there may have been two subsequent independent shifts to increased use of litter and vegetation matrices with related anatomical changes (A. moreoticus, A. fitzingeri), and one to increased use of crevices (A. marchi). Some members of Algyroides are strikingly similar in superficial morphology to particular species of the equatorial African genus Adolfus. This resemblance results from a combination of many shared primitive features plus a few independently acquired derived ones that are likely to give performance advantage in the relatively similar structural niches that these forms occupy. This study provides evidence that: (1) the use of a combination of molecular and morphological data may sometimes allow the estimation of ancestral anatomical features when these are otherwise unknown; (2) process considerations may permit a choice to be made in cases of character evolution where tree topology means that equally parsimonious alternatives exist; such decisions about character evolution may allow ecological shifts to be similarly assessed; (3) parallel evolution in ecological analogues may involve relatively few characters.
Variations in life‐history traits in the common frog Rana temporaria (Amphibia: Anura): a literature review and new data from the French Alps
Authors: Miaud Claude , Guyétant Robert , Elmberg Johan
Published: February 2006

Life‐history traits of Rana temporaria were studied in an alpine French population and in the literature. In the living frogs, mean adult body length was greater in females than in males. Sexual dimorphism in body length was 0.109 using Lovich & Gibbon's (1992) formula, but tended to decrease with age. Age of adult frogs was assessed by skeletochronology, and age distribution was not significantly different between the sexes (range 4–15 years in males, 5–12 in females). Adult survival rate was about 0.80 in both sexes. Once maturity was reached, the total expected longevity was 6.1 years in males and 5.5 years in females. Age and body length were positively correlated in both sexes. The growth coefficient (K) was 0.47 in males, and 0.55 in females, mainly reflected as faster female growth between metamorphosis and maturation. Growth rate generally decreased before sexual maturity was reached. On average, females matured 1 year later than males. Newly metamorphosed froglets averaged 16.1 mm. When combined with published data from 12 European populations of R. temporaria, the following general patterns emerge. Mean adult body length is significantly greater in females than in males, and mean body length at maturity shows the same trend. Variation in mean age at maturity and in longevity are considerable among populations, but there is no consistent trend of difference between the sexes. Body length and age are correlated between males and females, i.e. populations with long and old males also have long and old females. Mean adult body length, mean body length at maturity, age at maturity, and longevity all increase with decreasing activity period. Adults exposed to a short activity period grow slower but attain a greater final length. Sexual dimorphism in body length generally increases as activity period gets shorter. Polygons describing norms of reaction for maturation in an age–body length space are similarly oriented in both sexes, but with a wider range in age for females. This is due to an older age at maturity for females in populations with a short activity season. Mean age and length at maturity are significantly correlated in females, but not in males, partly supporting the hypothesis that this species has a flexible pattern of development. Observed patterns are compared with predictions from life‐history theory, paying attention to all life stages and environmental variation.
Small mammal communities and fire in the Brazilian Cerrado
Authors: Vieira Emerson M.
Published: February 2006

The Cerrado biome is a complex of open forests, gallery forests and savanna vegetation that harbours about 60 species of small mammals. Despite the frequent occurrence of fire in this habitat, few studies have analysed its effects on the small mammal communities in the Cerrado. The purpose of this study was to compare small mammal communities of two Cerrado areas with different fire frequencies (2–3 years or more than 18 years since the last fire). Species diversity, species composition, and relative abundance of the most common species of these communities were analysed in both areas before and after fire. One trapping grid was established in each of the two areas. These areas were sampled monthly or bi‐monthly during 1 year before and 1 year after prescribed fires. Both areas had communities with similar species composition, but the protected site had more species, before and after fire (seven and eight, respectively), than the frequently burned site (five and six species, respectively). Both sites showed significant post‐fire changes for a short time period (3 months), but only the area that had been protected against fire for more time showed significant post‐fire changes in relative abundance of the most common species (the murid rodents Bolomys lasiurus, Calomys callosus, C. tener, Oryzomys subflavus, and Thalpomys cerradensis) for the 1 year following fire. Overall diversity tended to be greater in the protected site both before and after fire. Species composition and diversity indices of the small mammal communities were relatively unaffected by the fires. Thalpomys cerradensis, however, appeared to use only areas that burn frequently and C. callosus showed an immediate post‐fire increase in population size in both areas, contrasting with a simultaneous decrease in number of B. lasiurus.
Hunting and social behaviour of leopard seals (Hydrurga leptonyx) at Seal Island, South Shetland Islands, Antarctica
Authors: Hiruki Lisa M. , Schwartz Michael K. , Boveng Peter L.
Published: February 2006

The hunting behaviour of leopard seals Hydrurga leptonyx was monitored opportunistically at Seal Island, South Shetland Islands, during the austral summers from 1986/87 to 1994/95. Leopard seals used several methods to catch Antarctic fur seal pups Arctocephalus gazella and chinstrap penguins Pygoscelis antarctica, and individuals showed different hunting styles and hunting success. One to two leopard seals per year were responsible for an average of 60% of observed captures of fur seal pups. Leopard seals preyed on penguins throughout the summer, but preyed on fur seal pups only between late December and mid‐February. Hunting behaviour differed significantly between different locations on the island; fur seals were hunted only at one colony, and penguins were hunted in several areas. The relative abundance of prey types, size of prey in relation to predator, and specialization of individual leopard seals to hunt fur seal prey probably influence individual prey preferences among leopard seals. On five occasions, two leopard seals were seen together on Seal Island. Possible interpretations of the relationship between the inter‐acting leopard seals included a mother–offspring relationship, a consorting male–female pair, and an adult leopard seal followed by an unrelated juvenile. In two incidents at Seal Island, two leopard seals were observed interacting while hunting: one seal captured fur seal pups and appeared to release them to the other seal. Observations of leopard seals interacting during hunting sessions were difficult to confirm as co‐operative hunting, but they strongly implied that the two seals were not agonistic toward one another. The hunting success of individual leopard seals pursuing penguins or fur seals is probably high enough for co‐operative hunting not to become a common hunting strategy; however, it may occur infrequently when it increases the hunting productivity of the seals.
Testicular and ovarian development in the harbour porpoise (Phocoena phocoena)
Authors: Karakosta C. V. , Jepson P. D. , Ohira H. , Moore A. , Bennett P. M. , Holt W. V.
Published: February 2006

Testicular and ovarian development in neonatal and juvenile harbour porpoises Phocoena phocoena was examined, using tissue from animals (males n= 65 and females n= 10) stranded or caught off the coast of England and Wales. Classification of the animals according to their stage of sexual development was undertaken using characteristics of gonadal morphology. Developmental correlates of the immature testis were increased incidence of prespermatogonia in seminiferous tubules, and the increasing proportion of testicular volume occupied by the seminiferous tubules. Using a low magnification (×200) assessment of testis sections, immature specimens could be grouped into three developmentally distinct classes, based on the relative amounts of interstitial and seminiferous tubule tissue and the frequency of prespermatogonia. Adult testes, showing either active spermatogenesis or seasonal quiescence, could be clearly distinguished from immature testes using histological criteria such as the presence of spermatocytes and spermatids. This classification system was used to determine relationships between testicular development and body size: males were classified as immature when they had body lengths < 135 cm and body weights < 30 kg; mature males always exceeded 140 cm in length and 40 kg in weight; and a transitional group, which was regarded as juvenile, had body lengths between 110 and 140 cm and body weights between 20 and 40 kg. Ovarian morphology was used to distinguish neonatal and juvenile females. Neonates displayed characteristic cords of naked ova which dispersed as development progressed. Neonatal animals had body lengths < 100 cm and body weights < 18 kg; within this group (n= 5) there were significant (P < 0.01) left‐right asymmetries in the number of naked ova present, the left ovary containing nearly twice as many ova as the right. Although this difference was not apparent in females with body lengths > 100 cm and body weights between 19 and 30 kg (juveniles) it could be related to the almost total asymmetry of ovulation from the left ovary in this species (Harrison, Brownwell & Boice, 1972).
Occurrence of the genus Chiasmocleis (Anura: Microhylidae) in the State of Alagoas, north‐eastern Brazil, with a description of a new species
Authors: Cruz C. A. G. , Caramaschi U. , Freire E. M. X.
Published: February 2006

The range of the genus Chiasmocleis found in the south‐eastern and southern parts of the Atlantic rainforest of eastern Brazil, is expanded to the north‐eastern region. Chiasmocleis alagoanus sp. nov. is described from two localities in the State of Alagoas. It is characterized by: medium size (snout–vent length 25.5–27.8 mm in females, 22.7–23.4 mm in males); snout short, tip truncate in dorsal and rounded in lateral profile; hand and foot not webbed; fingers and toes without lateral dermal spines; dorsal and ventral surfaces of body and limbs smooth, without dermal spines; colour on dorsum uniformly dark brown; venter roughly marbled in dark brown and pale cream.
Trends in the numbers and mortality patterns of sparrowhawks (Accipiter nisus) and kestrels (Falco tinnunculus) in Britain, as revealed by carcass analyses
Authors: Newton I. , Wyllie I. , Dale L.
Published: February 2006

The numbers of sparrowhawks Accipiter nisus received for study at Monks Wood Research Station increased greatly between 1963 and 1992, then declined by 50% in 1992–97. The long‐term increase reflected the national population recovery over this period and followed the reduction in the use of organochlorine pesticides. It was most marked in the eastern parts of Britain where the earlier population decline was greatest. The numbers of kestrels Falco tinnunculus received for study fluctuated greatly from year to year, and showed only a slight net increase over the study period. There was a marked increase in the late 1970s in eastern districts, the only areas where kestrels had obviously declined during the peak years of organochlorine use. The sparrowhawk carcasses revealed two peaks in recorded mortality: August–September, affecting mainly recently independent juveniles; March–April, affecting similar numbers of adults and juveniles. Kestrels showed no obvious seasonal peak in recorded mortality, but fewest carcasses were received in the early breeding season April–May. Among sparrowhawk carcasses, the sex ratio was significantly biased towards females (0.8 male to 1.0 female), but among kestrel carcasses the sex ratio was close to unity. Overall, 64% of sparrowhawks and 69% of kestrels were juvenile (= first year) birds, implying a mean first‐year mortality in the two species of 64% and 69%. The proportion of juveniles among sparrowhawk carcasses increased during the study period (probably reflecting improved breeding success), but the proportion of juveniles among kestrel carcasses showed no long‐term trend. The most important causes of recorded deaths in both species were collisions (65% for sparrowhawk and 35% for kestrel) and starvation (18% for sparrowhawk and 40% for kestrel). The frequencies of different mortality causes recorded among carcasses found were unlikely to reflect their frequencies in the population at large, but they did reveal changes over time. During 1962–97, deaths attributed to organochlorine poisoning and shooting declined in frequency, while accidental deaths increased in frequency, especially collisions with road vehicles in kestrels and with windows in sparrowhawks.
Compliant walking in primates
Authors: Schmitt Daniel
Published: February 2006

It is now well recognized that terrestrial mammals can maintain equivalent bone stresses despite dramatic differences in body size through the adoption of extended limb positions during locomotion. However, this dynamic solution is not available to all mammals. Medium‐ and large‐bodied arboreal mammals, such as anthropoid primates, must maintain relatively gracile and mobile limbs in order to manoeuvre in a discontinuous arboreal environment. But they must also use flexed (i.e. crouched) limb positions in order to maintain balance on arboreal substrates, thus subjecting their gracile limbs to relatively high loads. To determine how primates resolve this conflict between their kinematics and their morphology, five species of Old World monkeys were videotaped with lateral, frontal, and overhead cameras while they walked at a range of natural speeds along a runway and raised horizontal poles instrumented with a force platform. Kinematic and kinetic data on the forelimb show that during arboreal quadrupedalism, Old World monkeys do crouch when travelling on arboreal supports compared to the ground. Simultaneously, they lower vertical peak reaction forces and thereby reduce and reorient the peak resultant substrate reaction force, so that moment arms and moments are roughly equivalent on poles and the ground. This is accomplished through the adoption of a compliant walking gait characterized by high degrees of forelimb protraction, substantial elbow yield, low vertical oscillations of the body, and long contact times. The use of a compliant walking gait appears to be extremely rare among mammals and is most likely related to an initial primate adaptation to quadrupedal locomotion on terminal branches. This gait represents a previously unrecognized dynamic postural mechanism for maintenance of similar bone stresses and safety factors in both arboreal and terrestrial environments.
Regulation of reproduction in female common mole‐rats (Cryptomys hottentotus hottentotus): the effects of breeding season and reproductive status
Authors: Spinks A. C. , Bennett N. C. , Jarvis J. U. M.
Published: February 2006

The effects of breeding season and reproductive status on female reproduction were investigated in the common mole‐rat, Cryptomys hottentotus hottentotus, a co‐operatively breeding rodent that exhibits seasonal breeding and a reproductive division of labour. Body mass, reproductive tract morphometrics, ovarian histology and plasma testosterone concentrations were studied in 80 females from 42 wild‐caught colonies. Although the birth of offspring is restricted to the summer, qualitative analysis of ovarian histology revealed that females retained reproductive function during the winter non‐breeding period. Seasonal differences were found in ovarian morphometrics and testosterone concentrations and are probably associated with the occurrence of pregnancy in reproductive females during the breeding period. The continuance of reproductive function during the non‐breeding period in female common mole‐rats parallels the situation in males, and is believed to be important in dispersal in C. h. hottentotus. The non‐breeding period coincides with the period of maximal dispersal opportunities in the winter rainfall areas inhabited by the common mole‐rat. Reproductive activation in dispersing animals may aid intersexual recognition, assist pair‐bond formation and thereby facilitate independent reproduction. Reproductive and non‐reproductive females exhibited a similar degree of reproductive function, and as for season, the only clear‐cut status‐related differences were associated with the occurrence of pregnancy in reproductive females. This absence of a physiologically well‐defined suppression of reproduction in female common mole‐rats is similar to the situation in males. Incest taboos between philopatric siblings may negate the need for a rigorous suppression of reproduction in subordinate colony members of this obligate outbreeder.
The comparative biomechanics of an ophidian defensive behaviour: head triangulation in hognose snake (Heterodon) and an egg‐eating snake (Dasypeltis)
Authors: Young B. A. , Lalor J. , Solomon J.
Published: February 2006

Head triangulation is a regular component of the defensive behaviour of both Heterodon and Dasypeltis. In Heterodon platyrhinos, the triangulation is achieved primarily through rotation of the quadrate in the transverse plane with the distal end of the quadrate moving dorsad. The quadrate is pulled by the m. cervicomandibularis acting in conjunction with one of the jaw adductors. Head triangulation in Dasypeltis scabra is produced by rotation of the quadrate mainly in the frontal plane with the distal end of the quadrate moving craniad. Experimental analysis documents that contraction of the m. adductor mandibulae externus superficialis is temporally linked to this displacement of the quadrate. The presence of two different mechanical bases for head triangulation in these distantly related colubrids suggests that this behavioural display has evolved independently in these ophidian lineages.
Thyone herberti, a new dendrochirotid species from the east coast of South Africa (Echinodermata: Holothuroidea)
Authors: Thandar Ahmed S. , Rajpal Vish
Published: February 2006

A new species of a dendrochirotid holothuroid, Thyone herberti, is described from the deep waters of Matigulu, KwaZulu‐Natal, South Africa. The new species is distinct from other species of the genus in the form of its calcareous ring, in which the radial plates are prolonged posteriorly before bifurcating, and in the presence of non‐rosette‐like perforated rods and plates in the tentacles and the introvert. The new species increases to eight the number of southern African species currently classified in the genus Thyone.
Impact of season, habitat and research techniques on diet composition of roe deer (Capreolus capreolus): a review
Authors: Cornelis Johnny , Casaer Jim , Hermy Martin
Published: February 2006

We summarize the information on the diet of roe deer Capreolus capreolus found in 33 European studies. After giving a short overview of the differences between the existing studies, we compare the information for each season. We submit the information, summarized in a matrix of 83 cases on 10 food groups, to a detrended correspondence analysis (DCA) and a two‐way indicator species analysis (TWINSPAN). We calculate weighted averages grouping the information by season, habitat, research method and their cross‐products. The weighted averages are also used as input for a multivariate ratio analysis. Since the available food items dictate the possible diet composition we further investigate the influence of the habitat on the reported food selection. The influence of season on the diet composition is compared with the effect of the habitat, and other factors such as research method and geographical location of the study site. The review shows that there is relatively little seasonal variation in the diet composition, which is more closely correlated to the habitat than to the season.
A mitochondrial DNA perspective on the evolution of Iberian Discoglossus (Amphibia: Anura)
Authors: Garcí‐París M. , Jockusch E. L.
Published: February 2006

Sequences of a mtDNA gene, cytochrome b, were used to generate a phylogenetic hypothesis for the evolution of Iberian archaeobatrachian frogs of the genus Discoglossus. Results from the inferred phylogenetic branching pattern and the sequence divergence among species and populations support the following: (1) the two endemic species from Iberia, D. galganoi and D. jeanneae are sister taxa and are reciprocally monophyletic with respect to their mtDNA; (2) the geographic distribution of these two morphologically cryptic species differs considerably from previous expectations. D. galganoi is limited to the metamorphic granitic and shale substrates of western Spain and Portugal, while D. jeanneae extends over the limestone and gypsum substrates of most of eastern Spain from the Strait of Gibraltar to the Pyrenees; (3) sequence divergence between D. galganoi and D. jeanneae averages 8.6%, suggesting that the two lineages diverged before the Mio–Pliocene boundary. We suggest that these lineages were isolated by the opening of the Betic Strait and that isolation has been maintained until recently by the Guadalquivir River Basin; (4) all specimens of D. jeanneae, from the central Pyrenees in the north to the southern end of the Iberian Peninsula have nearly identical cytochrome b haplotypes, clear evidence of a rapid relatively recent (Late Pleistocene–Quaternary) expansion of the species; (5) populations of D. pictus from northeastern Spain are highly divergent from all other Discoglossus studied and do not fall within the Iberian clade.