bluuebunny/crossref_metadata_2025 huggingface dataset:
Causes and consequences of egg mass variation between and within blue tit clutches
Authors: Nilsson J. ‐Å. , Svensson E.
Published: March 2009

Causes of egg‐size variation between and within clutches were studied in clutches of the blue tit (Parus caeruleus L.). We measured the mass of each egg in the laying sequence in unmanipulated clutches, in clutches of parents experimentally supplied with extra food before egg‐laying, and in clutches of parents supplemented with extra food after the start of egg‐laying. Hatchlings were weighed at an age of two days and their mass was found to be positively related to egg mass. No general trend of decreasing or increasing egg mass was found within the laying sequence. Females provided with extra food before egg‐laying laid clutches with significantly less variation in egg mass than did control females. The reason for this was that the first‐laid egg of unmanipulated females was lighter than the rest of the eggs in the clutch. This pattern disappeared in clutches of females receiving extra food. Thus, the reduction in egg mass variation among clutches of foodsupplemented females depended on an ability of these females, in contrast to control females, to lay a first egg of the same mass as the rest of the clutch. Eggs laid after the initiation of incubation were significantly heavier than equivalent eggs in those clutches where incubation started after clutch completion. The difference was small, however, and the adaptive significance of the finding is questionable. We argue that intra‐clutch variation in egg mass is connected with greater fitness consequences than in inter‐clutch variation. Furthermore, our results indicate that energetical constraints on the laying female are more important as a cause of the observed intra‐clutch variation in egg mass than are adaptive responses to the environment.
The role of the liver in the cutaneous respiratory compensation of the frog (Rana esculenta)
Authors: Frangioni G. , Borgioli G.
Published: March 2009

Experiments on anaesthetized specimens of Rana esculenta (L.) demonstrate that at low temperatures (6°C) the liver of the frog‐like the spleen of the newt‐regulates cutaneous respiration, storing red blood cells when the animal is well oxygenated and releasing these into circulation under conditions of hypoxia. During the shift from the congested to decongested state, the liver is reduced to about two‐thirds of its weight, while the erythrocyte concentration and correlated parameters in the bloodstream can increase by more than 50%. At higher temperatures (18°C) this compensatory mechanism becomes inefficient and the liver oversees the survival of the hypoxic organism for a fairly long period of time (about 5 hours) by releasing glucose for anaerobic glycolysis.
The flight of pipistrelle bats Pipistrellus pipistrellus during pregnancy and lactation
Authors: Hughes Patsy , Rayner J. M. V.
Published: March 2009

A group of 20 pipistrelle bats were taken into captivity and allowed free flight and association within a flight room where they gave birth to and successfully reared 17 young. The flight of the females was recorded during pregnancy, early lactation and post‐lactation by using stroboscopic stereophotogrammetry (153 flights reconstructed in total). During the investigation body mass was altering owing to reproductive condition, and changes in mass were recorded daily for all (adult and juvenile) bats during the entire study period, which lasted from two weeks before the last birth until release, when the oldest baby was 43 days old. All bats were individually marked, and detailed morphological measurements were made. Pregnant and post‐lactating bats were heavier than lactating bats, which showed the lowest wingbeat frequencies. The flight speeds of pregnant, lactating and post‐lactating bats showed no significant differences, and this may be because the pregnant bats appeared to have a wider scope for selecting flight speed than the other two reproductive groups, or than animals studied previously. The group of bats as a whole decreased flight speed (scaling as M‐043) and increased wingbeat frequency (scaling as M0.58) as their mass increased. Wingbeat amplitude showed no relation to body mass, wing area or span, flight speed or frequency. A flight performance model applied to the experimental results and optimum flight conditions is used to predict cost of transport and mechanical power for steady flight, and equilibrium wingbeat amplitude which is compared with observations.
Diet and feeding ecology of saddle‐back (Saguinus fuscicollis) and moustached (S. mystax) tamarins in an Amazonian terra firme forest
Authors: Peres C. A.
Published: March 2009

The feeding ecology of two small‐bodied primate species—saddle‐back (Saguinus fuscicollis auilapiresi) and moustached tamarins (S. mystax pileatus)—occurring in stable, mixed‐species groups was studied in a terra firme forest site in the upper Urucu River, Amazonas, Brazil. Ecological data are based primarily on one mixed‐species group of 5–8 saddle‐back and 8–10 moustached tamarins. The overall vegetative and animal‐prey components of each tamarin species' diet, their selection of food species, and the seasonal variation in their use of plant resources are described, and compared to those of callitrichids elsewhere. The extremely diverse diet of tamarins included at least 136 tree, 33 vine and liana, 12 epiphyte and nine shrub species, as well as a wide range of prey items. They fed primarily on ripe fruit pulp of most of these species for most of the year, but shifted to floral nectar and plant exudates of a few key plant species during the dry season. Taxonomic overlap in plant diet was nearly complete between the two tamarin species, but they diverged considerably in their prey capture techniques. Saddle‐backs used the low forest understorey, and manipulatively searched for sedentary prey concealed within discrete, usually rigid, microhabitats, whereas moustached tamarins used the midstorey where they visually searched for mobile prey well exposed on foliage. These and other feeding and foraging patterns are discussed in the light of other callitrichid species studied to date.
The influence of birth date on the development of seasonal cycles in red deer hinds (Cervus elaphus)
Authors: Sibbald A. M. , Fenn P. D. , Kerr W. G. , Loudon A. S. I.
Published: March 2009

The relative importance of age and photoperiod in the timing of seasonal cycles was studied in red deer during the first 18 months of life. Seasonal cycles of appetite, live‐weight change, coat growth, oestrus and metabolic rate were examined in two groups of seven hind calves born in early May (group E) or nine weeks later in July (group L).

There was no difference between groups in the timing or amplitude of the seasonal voluntary food intake (VFI) cycle, or in the timing of seasonal changes in rate of live‐weight gain, although mean live‐weight gain was significantly greater for group L than group E during the first winter of life.

Four animals in group L retained their calf coats throughout the first winter. In group L, the first summer coat fibres appeared approximately four weeks earlier, and mean fibre length for the subsequent winter coat was longer in group L than in group E. There was no difference between groups in the timing or amplitude of the seasonal cycle of plasma prolactin concentration, or in the incidence and mean time of onset of puberty.

There was no difference between groups in mean energy expenditure per unit of live weight at any time of the year. Mean daily energy expenditure was significantly higher in summer than in winter, but values measured when the animals were resting and corrected for differences in VFI were similar throughout the year.

It is concluded that the seasonal cycles of appetite, live‐weight change and oestrus in young red deer hinds are not modified by age, although the normal cycle of coat replacement can be disturbed in animals born towards the end of the calving season.
Defecation, apparent absorption efficiency, and the importance of water obtained in the food for water balance in captive brown long‐eared (Plecotus auritus) and Daubenton's (Myotis daubentoni) bats
Authors: Webb P. I. , Speakman J. R. , Racey P. A.
Published: March 2009

Mean apparent dry mass absorption efficiency by P. auritus fed on mealworms was 0.853 (S.D.=0.4, n=43). Mean apparent energy absorption efficiency by P. auritus and M. daubentoni fed on mealworms was 0.90 (S.D.=0.007, n=8). The mean energy content of mealworms was 28.6 kJ.g‐1 dry mass (S.D.=1.1, n=8), and that of faeces was 19.5 kJ.g‐1 (S.D.=0.7, n=8) in P. auritus and 19.9 kJ.g‐1 (S.D.=1.3, n=8) in M. daubentoni. Water content of mealworms was 61.1% wet mass (S.D.=1.4, n=173); water content of faeces was 73.3% in P. auritus (S.D.=6.8, n=76) and 72.3% (S.D.=7.0, n=42) in M. daubentoni. Oven‐dried mealworms consisted of <1% ash, <1% carbohydrate, 31% lipid and 39% protein. We suggest that the dry mass unaccounted for (28%) represented chitin, of which 59% was apparently absorbed during digestion. Apparent absorption by mass of both lipid and protein by P. auritus fed on mealworms was greater than 90%. Cumulative post‐prandial defecation was sigmoidal in both bat species with 50% (by mass) of faeces being voided within 4 h and 95% within 12 h of feeding. On the basis of previous measurements, using doubly‐labelled water, of daily energy expenditure and water flux in free‐living P. auritus, we predict that water intake via the food, as free water and as potential metabolic water, represents 20 to 40% of total daily water flux for P. auritus during lactation in the wild.
The influence of egg‐size, mass and composition upon hatching success in the short‐tailed shearwater Puffinus tenuirostris (Aves: Procellariiformes)
Authors: Meathrel C. E. , Skira I. J. , Bradley J. S. , Wooller R. D.
Published: March 2009

Short‐tailed shearwaters in Bass Strait, Australia, exhibited extreme synchronicity in laying during 1991. Egg dimensions and masses varied by approximately 40% between females and were related to the date of laying but not the fate of the egg at hatching. The composition of eggs was similar to other petrels, and typical of semiprecocial species. Larger egg‐size was attributable to relatively more albumen, but less yolk. Thus, hatching succcss may be proximately constrained by behavioural attributes of the patents.
Evolutionary trends in the dentition of true lemmings (Lemmini, Cricetidae, Rodentia): functional‐adaptive analysis
Authors: Abramson N. I.
Published: March 2009

This paper offers a functional analysis of structure and variation trends in the dentition of species of the tribe Lemmini Simpson, 1945. The striking differences in the structure, trends in variation and rate of evolution between the Lemmini and all other members of Arvicolinae can be understood from the quite different functioning of the masticatory apparatus. The polarity of character states in the dentition of the Lemmini is discussed. Suggested polarity is supported by the palaeontological and functional evidence. The distinctive means of increasing the efficiency of the masticatory apparatus seen in Lemmini not only reflects definite genetic history but can also be explained by their very unusual food specialization and the demands it imposes on the mechanics of their masticatory apparatus.
The genus Paragehyra (Reptilia: Sauria: Gekkonidae) in southern Madagascar
Authors: Nussbaum R. A. , Raxworthy C. J.
Published: March 2009

Paragehyra Angel is a gekkonine genus endemic to Madagascar. From 1929 until the present, the genus was represented only by the holotype of the single known species. Paragehyra petiti. The type locality of P. petiti is in the driest part of Madagascar (south‐west) where rainless periods may exceed 11 months and the original vegetation consists of thorn scrub or dry deciduous forest. No new individuals of P. petiti were observed. However, a second, undescribed species of the genus was discovered in October 1990 on the opposite side of the island (south‐east) in primary‐low montane rainforest. The new form was observed at four localities at the southernmost extremity of rainforest in Madagascar.
A phylogenetic interpretation of hamacanthids (Demospongiae, Porifera), with the redescription of Hamacantha popana
Authors: Hajdu Eduardo
Published: March 2009

The study of the phylogenetic relationships of Hamacantha Gray. 1867 showed it to be more closely related to mycalids than to desmacellids, on the basis of its highly cavernous choanosome with stout ascending tracts of megascleres, easily detachable ectosome with a reticulation of megasclere bundles, and presence of rosettes and of true toxa. Since Pozziella Topsent, 1896 is recognized as a good genus, close to Hamacantha. the family name Hamacanthidae Gray, 1872 may be retained for this assemblage. This family is the sister‐group of the Mycalidae Lundbeck, 1905 branch, and they both have Desmacellidae Ridley & Dondy, 1886 as sister‐group. A cladogram expressing these relationships is provided and compared with previous ones in the literature. Mycalidae, Hamacanthidae, Desmacellidae, Cladorhizidae and ‘guitarrids’ form a monophyletic group by sharing two derived characters: faintly‐necked styles, and sigmancistra derivatives.
Use of time and space by platypus (Ornithorhynchus anatinus: Monotremata) along a Victorian stream
Authors: Serena M.
Published: March 2009

Radio‐tracking and mark recapture methods were used to characterize the spatial organization and temporal activity patterns of free‐ranging platypuses in southern Victoria. The study area supported an estimated 1.3‐2.1 adult or subadult animals per kilometre of stream in the three summers sampled. The individual home ranges of 15 radio‐tagged animals comprised 0.33‐2.28 km of stream; animals foraging exclusively in the stream had significantly longer ranges (mean=1.40 km) than animals which also foraged in associated pond habitats (mean=0.64km). Home ranges of grown females overlapped with those of neighbouring grown females, subadult and adult males, and juveniles (<l y old) of both sexes. While the home ranges of a subadult and adult male, and subadult and juvenile male also overlapped substantially, only one sexually mature male was trapped at any given point in time, suggesting that adult males may occupy mutually exclusive home ranges in the study area. Most platypuses were observed to den at more than one location: burrow sharing was recorded in the case of a subadult and adult male, two grown females, a grown female and independent first‐year female, and two independent first‐year females. The mean length of time that nine individuals spent in dens per resting period varied from 11.6‐16.7 h. In addition, two grown females remained inactive in dens for longer periods (3‐6.5 days) in late May‐June.
Morphological adaptation of the digestive tract in relation to feeding ecology of raptors
Authors: Barton N. W. H. , Houston D. C.
Published: March 2009

The study examines some aspects of gross morphology in Falconiformes and Strigiformes. It is hypothesized that, in predatory birds, hunting strategy might influence the relative size of skeletal musculature and length of the digestive tract. Falconiform species were categorized as either ‘attackers’ or ‘searchers’ depending on the degree to which active, powered pursuit is required for prey capture. Attacking species feed predominantly on avian prey, requiring extreme agility, speed and acceleration for prey capture. Searchers feed largely on relatively slow‐moving mammals and carrion. Comparisons between species of attackers and searchers showed that the former had heavier pectoral muscle mass, larger areas for flight muscle attachment and higher linearized wing loadings. Strigiformes had a pectoral muscle mass only half the size of that of attacking Falconiformes and had a correspondingly smaller sternum area. A skeletal body‐size measure was determined to enable calculation of intestine length independent of body‐size and shape differences. Attacking species have a small intestine which is 20–30% shorter than would be predicted on the basis of body‐size and 50% shorter than found in searchers of equivalent body‐size. Strigiformes that locate prey by active flight also have intestinal tracts shorter than expected. The likely effects of intestine length on digestive efficiency and food utilization are discussed and it is suggested that, in predatory birds, some species have evolved alimentary tracts that are shorter than necessary for maximum digestive efficiency in order to enhance prey capture.
Sexual behaviour of male and female tammar wallabies (Macropus eugenii) at post‐partum oestrus
Authors: Rudd Carl D.
Published: March 2009

This study describes the sexual behaviour of the adult male and female tammar wallaby from the time a female gives birth to the end of post‐partum oestrus. Eleven females were continuously observed from around the time of birth until up to 3 h after the last observed mating attempt. Males began to associate with females from around the time of birth, thus females appear to be attractive to males at, but not prior to parturition. Females subsequently allowed males to mate with them from 1.3±0.8h (mean±S.D.) post‐partum, although the first ejaculation was delayed until 1.8±0.8h after birth owing to intense intermale aggression directed towards any male which attempted to mate with an oestrous female. Mating chases, in which a post‐partum female was pursued by several males, were observed from 1.3±0.8h post‐partum. All of this mating activity usually occurred within the first 6h after birth.
Population structure and emergence order in the fruit‐bat (Rousettus aegyptiacus: Mammalia, Chiroptera)
Authors: Korine Carmi , Izhaki Ido , Makin David
Published: March 2009

Population size and emergence order of R. aegyptiacus were studied in the Abas cave. Haifa, Israel. Throughout the reproductive period adult females populated the cave and the adult population consisted mainly of adult females except during winter when higher numbers of adult males were recorded. The proportion of juveniles increased consistently from spring to winter. Thus, it is suggested that the Abas cave serves as a maternity roost. Adult females in the reproductive state emerged from the cave earlier that juveniles and adult males. Social factors and differences in nutritional demands which may correspond to this different emergence order are discussed.
Historical aspects of protandrous sex change in the anemonefish Amphiprion melanopus (Pomacentridae, Teleostei)
Authors: Godwin John
Published: March 2009

Gonadal structure and cellular composition were examined in juveniles, males and females of the protandric hermaphrodite, Amphiprion melanopus. Functional sex change was experimentally induced in the field and gonad structure was histologically examined both qualitatively and quantitatively at 10, 20, 30 and 45 days after its initiation. Juvenile gonads consist primarily of immature ovarian tissue. Functional male gonads are ovotestes with co‐existing mature spermatogenic tissue and immature ovarian tissue, while females possess only ovarian tissue. The initiation of sex change is marked by a rapid maturation of spermatogenic tissue and proliferation of putative oogonia. Gonads were essentially female by 20 days into sex change, but evidence of mature female function (marked by the initiation of vitellogenesis) was not observed until 45 days. Considerable variation between individuals was seen in quantitative measures of gonadal change in the early stages of sex change, but not in later stages. Progress in sex change as indicated by histological indicators was, however, consistent within stages. Duet systems for gamete transport changed from the male to the female form after all male tissue had been replaced.
Serratus ventralis function in vervet monkeys (Cercopithecus aethiops): are primate quadrupeds unique?
Authors: Schmitt D. , Larson S. G. , Stern J. T.
Published: March 2009

The serratus ventralis in mammals is a fan‐shaped scapulo‐thoracic muscle that is believed by most morphologists both to support body weight and to rotate the scapula during quadrupedal locomotion. Electromyographic studies of this muscle in cats, dogs and opossums confirm the dual supportive and rotatory roles of the serratus ventralis. Although this muscle has been studied in several primate species, the concentration on arboreal locomotion has resulted in an inadequate data set to permit direct comparisons to non‐primate terrestrial quadrupeds. In order to provide a more comparable data set, we examined cranial, mid‐ and caudal thoracic regions of the serratus ventralis during terrestrial quadrupedalism in the vervet monkey, Cereopithecus aethiops. Our results indicate that the serratus ventralis does support the body during the stance phase of quadrupedalism in this primate. However, unlike several non‐primate mammals, it plays a relatively insignificant rotatory role during swing phase.
Wing folding and free‐flight kinematics in Coleoptera (Insecta): a comparative study
Authors: Brackenbury J. H.
Published: March 2009

Relative movements of the main wing areas around the major flexion lines are compared during wing folding at rest, and during the supinatory phase of the flight cycle, which involves considerable wing deformation. Folding of the wing apex at rest is achieved by a combination of movements around the median flexion line (the main longitudinal flexion line), the principal transverse fold, and a variety of smaller, oblique ‘tucking’ folds. During flight, wing tip deformation is strongly influenced by elastic forces involved in the normal wing folding and unfolding processes. Those beetles possessing an inwardly sprung wing apex display partial folding at supination, associated with the temporary relaxation of the forces opposing spring recoil. These beetles also show enhanced mobility about the median flexion line which facilitates leading edge supination. The presence of the principal transverse fold may help to concentrate ventral flexure towards the wing tip. The wings of beetles possessing an outwardly‐sprung apex are much less affected by the presence of the flexion lines associated with folding. In these cases, enhanced supination of the leading edge, in the face of an overall increase in wing membrane stiffness, may be related to the presence of the highly‐sclerotized pterostigma.
Seasonal variation in resting metabolic rate and body temperature of streaked tenrecs, Hemicentetes nigriceps and H. Semispinosus (Insectivora: Tenrecidae)
Authors: Stephenson P. J. , Racey P. A.
Published: March 2009

Annual variations in resting metabolic rate (RMR) and body temperature (Tb) were measured in the streaked tenrecs Hemicentetes nigiceps and H. semispinosus. RMR in non‐reproducing, non‐torpid adults was lower than predicted by the Kleiber (1961) curve, supporting Genoud's (1990) hypothesis on BMR in hibernating mammals. Both species demonstrated a reduction in RMR and Tb during the austral winter and these changes were independent of body mass. H. semispinosus frequently roused from torpor to forage whereas H. nigriceps remained dormant throughout the winter, This contrast in activity patterns may result from altitudinal differences in species distributions. H. nigriceps may be an obligate hibernator whereas H. semispinosus, living at lower, warmer altitudes, may be a facultative hibernator. It is proposed that the ability of H. semispinosus to remain active during favourable climatic conditions allows winter breeding and increases annual reproductive output.
Chemosensory cells in the oral epithelium of Raja clavata (Chondrichthyes)
Authors: Whitear M. , Moate R. M.
Published: March 2009

Examination by scanning and transmission electron microscopy (SEM and TEM) has found no actual taste buds in the mouth of Raja clavata. Prominences of the epithelium on the roof and floor of the mouth, and on the oral valves, contain large numbers of innervated bipolar cells, not associated in the form of taste buds, with a cytology intimating that they have a chemosensory function. The apices of these sensory cells, each bearing a group of microvilli, protrude between the superficial epithelial cells. Neurite profiles are associated with the sensory cells; synaptic specializations are marked by a cluster of vesicles with inconspicuous dense cores and some densities on the cell membrane. Shrunken, electron‐dense, cell profiles are interpreted as apoptotic. Shrunken sensory cell profiles are commoner than similar epithelial cells, especially in young individuals, indicating a relatively rapid turnover of sensory cells. The epithelium contains a variety of granulocytic leucocytes, some of which contain large phagosomes.
Ranging behaviour and activity of red foxes (Vulpes vulpes: Mammalia) in relation to environmental variables, in a Mediterranean mixed pinewood
Authors: Lovari S. , Valier P. , Lucchi M. Ricci
Published: March 2009

The relationships between the main abiotic environmental variables, food availability, dict, activity and home range size of the fox in a Mediterranean mixed pinewood were assessed. Food habits were determined by faecal analysis on a weekly basis. Food availability was measured by weekly censuses. Radio‐tracking allowed the detection of fox movements and activity. Individual differences shown by a sample of four radio‐tagged foxes were analysed. Juniper berries (Juniperus oxycedrus) were the staple of the diet during the year, except in summer. Insects, mainly nocturnal Orthoptera and cicada larvae (Cicada orni), were the main prey in the warm season. Large vertebrates, mostly wild boars (Sus scrofa), were scavenged in winter. In the warm season foxes' activity depended largely on the pattern of activity of prey. Food habits tended to depend on food availability, which, in turn was mainly influenced by temperature. In spite of habitat similarity, individual differences in food habits were detected within the same season. Home ranges were larger in pinewood than in neighbouring heterogeneous habitats. Individual home range sizes were: (i) directly correlated to Orthoptera abundance and distribution; (ii) inversely correlated to the abundance of cicada larvae in diet. Resident males may exist in fox society, exploiting other males' territories when good clumped food resources are available.
Comparative studies of epididymal morphology and sperm distribution in dasyurid marsupials during the breeding season
Authors: Taggart D. A. , Temple‐Smith P. D.
Published: March 2009

The structural features of the epididymis and the number and distribution of spermatozoa along the duct, during the breeding season, were examined in two semelparous and three iteroparous dasyurid marsupials. Total numbers of epididymal spermatozoa were extremely low in all of these species when compared with epididymal sperm numbers in most other marsupials and eutherian mammals. Although semelparous dasyurids had significantly more epididymal spermatozoa than itcroparous species, very few spermatozoa were seen in the distal cauda epididymidis of any of the species examined. This coincided with distinct changes in duct shape and the surface area of the lumen in caudal regions which resulted in a reduced sperm storage capacity in the cauda epididymidis of these species. The data suggest that, like Antechinus stuartii (Taggart & Temple‐Smith, 1990a), sperm content of the ejaculates in these species will be extremely low, and that sperm motility and/or transport in the female tract is highly efficient. The functional and evolutionary significance of the reproductive strategies of semelparous and iteroparous dasyurid marsupials is still obscure and further study is needed to determine if the length of sperm storage in the female and sperm competition for storage sites is related to sperm distribution in the male and mating activities. This study does, however, clearly indicate that large numbers of spermatozoa are not required to ensure successful fertilization in either semelparous or iteroparous members of the family Dasyuridae.
Factors influencing population dynamics of the plains viscacha (Lagostomus maximus, Mammalia, Chinchillidae) in scrub habitat of central Argentina1
Authors: Branch Lyn C. , Villarreal D. , Fowler G. S.
Published: March 2009

Population dynamics of the plains viscacha (Lagostomus maximus), a highly social burrowing rodent, were studied in desert scrub habitat of central Argentina from 1984 to 1991. The viscacha population declined between 1984 and 1987 from 96 to three individuals, and all but one of eight social groups went extinct. Our data provide support for both food shortage and predation as important factors in the population crash.

During this study, rainfall was above average for the first three years and then fell below average. Vegetative cover, especially plant species consumed by viscachas, declined concurrently with the drop in rainfall. A decrease in body weights of adult viscachas and growth rates of young indicated that food was limited. Predation by mountain lions (Felis concolor) was high throughout the study. However, observations of mountain lions foraging in viscacha colonies increased during the decline of the viscacha population. Predation rates may have increased because viscachas spent more time searching for food, and they were in poor body condition.

Following the decline in the viscacha population and after a slight increase in rainfall, vegetation cover increased. However, the viscacha population did not recover except in areas that were burned subsequent to the population crash. Fire, a natural part of the ecosystem, may be necessary to reverse changes in vegetation that occur when viscachas are removed from the landscape, and to allow viscacha populations to recover.
Investigation of badger (Meles meles) setts using soil resistivity measurements
Authors: Butler J. , Roper T. J. , Clark A. J.
Published: March 2009

Eight badger (Meles meles L.) Setts (two main setts, four subsidiaries, one annex and one outlier) were surveyed by means of soil resistivity and magnetometry techniques, of a type normally used for the detection of buried archaeological remains. The results were compared with data concerning the underground sleeping locations adopted by radio‐collared badgers in the same setts. Of the eight resistivity surveys, six gave sufficiently detailed results for the overall size of the setts in question to be determined and for some features of the constituent tunnel systems to be discerned. Areas of low resistivity matched locations where radio‐collared badgers were found to sleep, so presumably corresponded with underground tunnels and chambers. Magnetometry surveys were not successful, probably because tunnels and chambers were too deep to be detected by this method.
Intraspecific life‐history variation in Radix plicatulus (Gastropoda: Pulmonata: Lymnaeidae)
Authors: Lam Paul K. S.
Published: March 2009

Life‐histories of Radix plicatulus (Benson, 1842) populations inhabiting two neighbouring sites on a Hong Kong stream were investigated. In one of the two sites, R. plicatulus co‐occurred with high densities of Pomacea levior which is known to prey on the egg capsules and hatchlings of sympatric gastropods. On the basis of general life‐history theory, I hypothesized that R. plicatulus which co‐occurred with P. levior should exhibit a life‐history strategy characterized by a delayed reproduction, a longer recruitment period and a larger number of breeding bouts per year as compared with contemporaries inhabiting the other site with low P. levior abundance. Reproductive patterns of the two populations observed in the field accorded with the expectations of general life‐history theory, and lent support to the hypothesis. However, laboratory culture experiments revealed no evidence of a genetic basis for the interpopulation differences. The importance of establishing a genetic basis for the interpopulation divergence before invoking an evolutionary explanation was discussed.
Factor affecting body mass of young fat dormics (Glis glis) at weaning and by hibernation
Authors: Pilastro A. , Gomiero T. , Marin G.
Published: March 2009

This paper describes the factors affecting body mass at weaning and by hibernation of young fat dormice (Glis glis) We studied a free‐living population in 1991 and 1992 in a mixed forest where 100 nest‐boxes were placed. In the two years, 128 females used the nest‐boxes to give birth and rear their litters and more than 900 dormice have been individually marked. Body mass of young at weaning was positively correlated to body mass of the mother in both years and to birth date in 1991, while litter size was negatively correlated to body mass of the young in 1992 only, when birth took place about two weeks later than in 1991. On the contrary, by the time of hibernation, young born later weighed significantly less than those born earlier in the season, and heavier young at weaning remained heavier by hibernation, while maternal body mass and litter size did not significantly affect body mass of young at this stage. Body mass of the mother was negatively related to the date of parturition and early breeding females lost weight during lactation, while females that bred later did not. It seems, therefore, that early breeding carries a cost that only females in good condition can afford. It appears that females may follow two strategies: those in poor body condition will delay pregnancy so that lactation occurs when environmental feeding conditions are at their best; those in good condition will breed earlier, since they can afford to lose weight during lactation. Their young will have more time to grow before hibernation and the mothers themselves will have a longer period of time for restoring their fat reserves.
Reproductive suppression in social Cryptomys damarensis colonies—a lifetime of socially‐induced sterility in males and females (Rodentia: Bathyergidae)
Authors: Bennett N. C.
Published: March 2009

The Damaraland mole‐rat, Cryptomys damarensis, is a highly social subterranean rodent that exhibits reproductive suppression. Inhibition of reproduction occurs in colonies of the Damaraland mole‐rat such that only one female and one or two males are reproductively active. A strict breeding system is set up in which the sole reproductive female initiates courtship and selects her mate who is paired with her throughout the year.

The present study has shown that in C. damarensis colonies, both adult and juvenile non‐reproductive females are anovulatory and have low concentrations of oestrogen, 2.2 ± 4.6 nmols/mmol creatinine (n = 133) throughout the year. In contrast, the reproductively active female has elevated concentrations of oestrogen during pregnancy, 95.0 ± 151.O nmols/ mmol creatinine (n = 17). The non‐reproductive females are rendered at least temporarily infertile in that, instead of the secondary follicles maturing and ovulating, they develop into luteinizing follicles. This suppression of ovulation is maintained for as long as there is a reproductive female in the colony. These data support the behavioural findings that non‐reproductive females are never involved in courtship or copulatory behaviour nor do they solicit male colony members. Thus a socially induced suppression of reproductive physiology is apparent in females.

In the male Damaraland mole‐rat, suppression of reproduction is due entirely to an inhibition of reproductive behaviour. The mean urinary concentration of testosterone of the reproductive male was 3.8 ± 3.7 nmols/mmol creatinine (n = 25) and that of the five non‐reproductive males 4.4 ± 5.3 nmols/mmol creatinine (n = 114). All male mole‐rats are capable of undergoing spermatogenesis and thus are physiologically capable of fertilizing the reproductive female.

It appears, therefore, that reproductive suppression amongst non‐reproductive female mole‐rats is more profound than that which occurs in non‐reproductive males. The latter are apparently restrained from sexual activity by being subordinate to the reproductive male(s), excluded from the pair bond and by being the progeny of the reproductive animals. Thus a predominantly behavioural control mechanism would be in force on male colony members.
Diet of common dolphins (Delphinus delphis) off the south‐east coast of southern Africa: opportunism or specialization?
Authors: Young Deborah D. , Cockcroft V. G.
Published: March 2009

A total of 297 common dolphin (Delphinus delphis) stomachs was used for these diet analyses. All originated from common dolphins incidentally captured in Natal, where their occurrence is strongly associated with an annual, northward fish migration, the sardine run, along the east coast. Thirty‐six fish and four cephalopod prey species were identified. Though 86.9% by weight of the diet was made up of only five prey species, common dolphins appear to feed opportunistically, their diet reflecting local prey abundance and availability. Prey were primarily small, easily‐caught, pelagic shoaling species, with the main prey being South African pilchard (Sardinops ocellatus). Although pilchard dominated the diet between 1974 and 1992, there were marked annual and seasonal fluctuations in dietary composition, reflecting changes in prey availability and abundance. There were clear differences in the contribution of particular prey species to the diet of different sex and size groups, with strong evidence for resource partitioning between groups. The influence of the annual ‘sardine run’, and the fish predators associated with it, on the diet, feeding biology and distribution of common dolphins is discussed.
Functional anatomy of the gastrointestinal system of Northeastern Atlantic minke whales (Balaenoptera acutorostrata)
Authors: Olsen M. A. , Nordøy E. S. , Blix A. S. , Mathiesen S. D.
Published: March 2009

The anatomy of the gastrointestinal system of Northeastern Atlantic minke whales (Balaenoptera acutorostrata) was investigated. The stomach consisted of four compartments. The first chamber, or forestomach, was non‐glandular and was lined with a keratinized stratified squamous epithelium. The tissue wet weight of the forestomach represented 10.4 ± 2.2% (n = 3) of the total gastrointestinal tract (GI‐tract). When maximally expanded with water, the forestomach contained from 68–321 litres (n = 3), while forestomach contents in situ ranged from 5–80 litres (n = 12), with a pH of 6.43 ± 0.28 (n = 12). An orifice, with a relaxed diameter of 27.8 ± 100cm (n = 8), separated the forestomach from the fundic chamber. The mucosa of the fundic chamber possessed gastric glands comprising parietal and chief cells. The contents of this chamber had a pH of 5.26 ± 1.02 (n = 12). The tissue wet weight represented 13.5 ± 1.9% (n = 3) of the total GI‐tract, and when maximally expanded with water, the fundic chamber contained 63–100 litres (n = 3). In situ contents of this chamber ranged from 2–25 litres (n = 12). A connecting channel, with a relaxed orifice diameter of 7.3 ± 3.7 cm (n = 8), joined the fundic chamber and the pyloric chamber. The mucosa of the pyloric chamber contained mucous glands only and no primary glands of digestion. The contents of the pyloric chamber had a pH of 3.60 ± 0.97 (n = 12). The tissue wet weight represented 2.8 ± 0.1% (n = 3) of the total GI‐tract, while the maximally expanded pyloric chamber contained 18–39 litres (n = 3). The pyloric sphincter, with a relaxed diameter of 3.6 ± 0.5cm (n = 8), terminated the stomach. The small intestine began with a duodenal ampulla, lined with mucous glands similar to those in the pyloric chamber. The contents of the duodenal ampulla had a pH of 3.24 ± 0.79 (n = 12). The tissue wet weight represented 1.4 ± 0.2% (n = 3) of the total GI‐tract, and its maximally expanded volume was 8–30 litres (n = 3). The tissue wet weight of the small intestine, caecum and colon represented 61.9 ± 1.3 (n = 3), 0.82 ± 0.48 (n = 3) and 8.7 ± 2.1% (n = 3) of the total GI‐tract, respectively. The lengths of the small intestine, caecum and colon were maximally 36, 0.4 and 4 m, respectively. The forestomach somewhat resembles that of ruminants, but the overall size of the stomach is small, and the length of the intestine short compared to ruminants.
Larval development of three blenniid species Aidablennius sphynx, Coryphoblennius galerita and Lipophrys canevai (Pisces: Blenniidae: Blenniini) in the western Mediterranean
Authors: Sabates Ana
Published: March 2009

The early stages of development of three blenniid species, Aidablennius sphynx (6.7–15.8 mm BL), Coryphoblennius galerita (4.3–13.9mm BL), and Lipophrys canevai (3.5–10.4 mm BL) are described from specimens collected in the western Mediterranean. The characteristics used for identification included meristic, developmental, morphological and pigmentation characters. Distinguishing characters of these species useful in differentiating them from other species of blenniids for which early stages are known in the Mediterranean are presented. Information on the occurrence of larvae and juveniles of these species off the Catalan coast (north‐western Mediterranean) is also given.
Food niche overlap and ecological separation in a multi‐species community of shrews in the Siberian taiga
Authors: Churchfield Sara , Sheftel B. I.
Published: March 2009

An investigation of the feeding habits and prey availability in a community of seven species of shrew (Insectivora: Soricidae) inhabiting the taiga of Central Siberia was carried out with the aim of quantifying levels of niche overlap and elucidating modes of ecological separation amongst these coexisting species. All species took a wide range of invertebrate prey, and overlap in the numbers of shared prey taxa was high, but differences in dietary composition of certain taxa reduced overlap between most species. Small species fed almost exclusively on small arthropods, mostly Araneae, Chilopoda and Coleoptera, while medium and large‐sized species took high proportions of oligochaetes. Prey were mostly taken in proportions approximately equal to their availability, although certain prey appeared to be selected. All shrews took prey in a range of sizes, and the high dietary occurrence of small invertebrates reflected their availability and high encounter rate in field samples. Dietary occurrence of small prey was negatively correlated, and large prey positively correlated, with body size of shrew. Smaller shrews were predominantly ground‐surface foragers while larger species were more subterranean, with body size and dietary occurrence of soil prey being positively correlated. Differences in prey size and foraging mode reduced niche overlap between shrew species of widely differing sizes. Each shrew species did not occupy a separate, well‐defined food niche. Instead, the community was sub‐divided into three functional groups: large and small species which tended towards specialization with relatively low levels of overlap, and intermediate, generalist species with higher levels of overlap.
Status, vocalization and breeding biology of two species of African bullfrogs (Ranidae: Pyxicephalus)
Authors: Channing A. , DU Preez L. , Passmore N.
Published: March 2009

There is much confusion concerning the identity of bullfrogs in southern Africa. Currently three subspecies are recognized, and introgression has been suspected. We demonstrate that in southern Africa there are two species: Pyxicephalus adspersus which has a long call, breeds during the day, and exhibits lek behaviour; Pyxicephalus edulis which is smaller, has a short call, breeds at night and does not exhibit lek behaviour.
Ontogeny of shell morphology and shell strength of the marine snails Littorina obtusata and Littorina mariae: different defence strategies in a pair of sympatric, sibling species
Authors: Lowell R. B. , Fletcher C. R. , Grahame J. , Mill P. J.
Published: March 2009

The sibling marine snails Littorina obtusata (L.) and Littorina mariae Sacchi & Rastelli are sympatrically distributed and the shells of both species are subject to similar breaking forces by predatory crabs. Nevertheless, the two species exhibit rather different growth and defence strategies. To determine growth patterns, we measured changes in five morphological variables with increasing shell length: body whorl thickness at the point of crushing force application, shell height (related to globosity), shell mass, body mass, and apertural lip thickness. We also measured ontogenetic changes in the ability to withstand shell crushing. For most morphological variables, L. mariae showed uniformly allometric growth of juveniles into adults. In contrast, L. obtusata usually exhibited a distinct change in growth pattern upon reaching maturity. As adults, L. mariae showed a more sustained increase in overall shell mass and in body whorl thickness (defence against crushing attacks) and also had proportionally thicker apertural lips (defence against peeling attacks). Littorina obtusata, however, grew to a larger size and their shells could accommodate larger bodies at all sizes. Furthermore, the strength of L. obtusata shells increased faster than could be accounted for by either overall shell mass or thickness at the point of force application, suggesting strengthening by other means such as changes in shell microstructure or shape (other than globosity). These results illustrate the viability of two contrasting antipredator strategies, despite a highly similar phylogenetic history and selective regime.
Injection of venom into an insect prey by the free hunting spider Cupiennius salei (Araneae, Ctenidae)*
Authors: Boevé Jean‐Luc
Published: March 2009

For the generalist spider Cupiennius salei, each particular predator‐prey interaction could be related to obligatory behavioural patterns. The injection of venom by the spider was studied in relation to prey weight and time of injection. Single crickets (Acheta domesticus) of a given weight were offered successively to a spider at 10 min intervals. The prey items were removed 5, 60 or 180 sec after the beginning of the attack, and their state of activity recorded. Prey mortality was assumed to reflect the amount of venom injected. With relatively small prey items, the spider regulated this amount and venom glands were gradually emptied during successive bites. The injection was slow, lasting at least 3 min, possibly by a succession of discrete injections as a response to attempts by the prey to escape. In contrast, with larger prey items, the injection occurred within 1 min and mostly emptied the glands during the first bite. Bites experimentally reduced to 5 sec never allowed a spider to empty the venom glands completely. Only the first prey attacked usually received a lethal amount of venom. This suggested that an initial dose can be injected rapidly and could be morphologically segregated from the remaining venom.