bluuebunny/crossref_metadata_2025 huggingface dataset:
Population biology of three‐spined sticklebacks,Gasterosteus aculeatus, in Scotland
Authors: Giles N.
Published: March 2009

The age of maturation, longevity and aspects of anti‐predator morphology were studied for sevenGasterosteus aculeatusL. populations in Scotland during 1978 and 1979. All seven populations are annual with less than 1% of adults surviving a second year. At the four mainland study sites, breeding adult sticklebacks were larger than at any of the three Hebridean sites. Adult females were larger than adult males at all sites, except Lennox Castle where parasitism may account for the lack of sexual dimorphism. Two of the Hebridean sites, Loch Fada and Loch a Bharpa have spine‐deficientG. aculeatuspopulations which are morphologically unprotected from predation. In the five normally spined populations, some aspects of defensive morphology (index of increase in critical dimension, ventral spine size) are associated with predation risk, while others (lateral plate number) are not. These data are discussed in relation to the current stickleback literature.
Hilltopping, leks and female choice in the Carpenter bee Xylocopa (Neoxylocopa) varipuncta
Authors: ALCOCK J. , SMITH A. P.
Published: March 2009

The mating system of the Carpenter bee, Xylocopa (Neoxylocopa) varipuncta Patton, closely resembles the leks of certain vertebrates. Males defend hovering stations at small creosote bushes on ridgetops in the Sonoran Desert, as well as at large ironwood trees in dry washes. Ridgetops, like washes, may provide orientation guides for dispersing females, channelling potential mates to waiting males. During the height of the two month flight season, both males and females were more concentrated on the ridge than in the wash. Males were particularly densely aggregated at or near two prominent peaks on the study ridge. At times, two or more males occupied the same creosote bush. Females visited hovering males infrequently, and exhibited a high degree of freedom in mate choice, usually rejecting males after a close inspection.

The reduction in territorial intolerance exhibited by some males at ridgetop sites may occur: (1) because of the costs of repelling many intruders and (2) because females may choose among males through direct analysis of male phenotype, rather than by selecting a male on the basis of territory position.
Aspects of the biology of Pilot whales (Globicephala melaena) in recent mass strandings on the British coast
Authors: MARTIN A. R. , REYNOLDS P. , RICHARDSON M. G.
Published: March 2009

Five mass strandings of Pilot whales, involving from 23 to 40 animals, occurred on the British coast between 1982 and 1985. The sex ratio in all strandings was biased towards females (62% overall), but more than one mature male was present in each group. A multi‐male, polygynous social system is suggested. Growth is rapid from a mean body length at birth of 1.78 m to about 3 m at 2–3 years. Thereafter, males grow faster than females and attain a greater body length by some 18–25%. Maximum body lengths in this study were of a 6.3 m male and a 5.5 m female. The greatest ages determined were of a 20‐year‐old male and a 25‐year‐old female, but there is a possibility that readable dentine is not deposited in the teeth of older animals and that some whales are thus of a greater age than can be detected. Females become sexually mature at about seven years of age and a body length of 3–4 m. Some reach sexual senility before death. Males mature at a greater age and at about 5 m in length. Annual calf production is about 11% and no seasonality in parturition could be detected. Pollutant levels are generally within the range of those published for odontocetes, but PCB levels are higher than any yet found in other Pilot whale populations. Evidence of squid was found in three digestive tracts. Blubber thickness increases with the size of the animal, reaching 35–65 mm in adults. The existence of an annual, rigid north‐south migrational pattern is unlikely.
The chemosensory behaviour of Lithobius forficatus. 1. Evidence for a pheromone released by the coxal organs (Myriapoda: Chilopoda)
Authors: LITTLEWOOD P. M. H. , BLOWER J. G.
Published: March 2009

The behaviour of the Common brown centipede, Lithobius forficatus (.L.) is investigated with reference to the function of the coxal organs which are a peculiar and characteristic feature of Chilopoda. Previous studies of these organs in centipedes have been largely morphological and have relied on ultrastructural comparisons with other arthropod epithelia of disparate functions. Evidence is presented which suggests that the coxal pores release a sex‐specific pheromone. The nature of intraspecific interactions in L. forficatus is discussed.
Egg formation and the pre‐laying period of the Common guillemot Una aalge
Authors: BIRKHEAD T. R. , NEVO A. J. DEL
Published: March 2009

The patterns of colony attendance of male and female Common guillemots, relative to calendar date and relative to the female's laying date during the three weeks prior to egg laying, are presented. The probability of a male being at the colony was consistently higher than that for females. Male attendance peaked in the three days before his mate laid: female attendance was lowest at this time. Examination of the yolk showed that the egg was formed over 14–15 days, with yolk deposition (of first eggs) taking 11–5 days, and a lag period (between the end of yolk deposition and laying) of 3–4 days. Yolk deposition occurred over a shorter period (9–3 days) in replacement eggs, and followed a different pattern from first eggs.
A laboratory study of optimal behaviour and the costs of net construction by Polycentropus Havomaculatus (Insecta: Trichoptera: Polycentropodidae)
Authors: DUDGEON DAVID
Published: March 2009

Metabolic rates of Polycentropus flavomaculatus larvae in a flow‐through respirometer at 15°C were 17 % higher during net spinning than while larvae were resting. The energy content of net silk and caddisfly tissues, obtained by bomb calorimetry, were 23–367 J mgAFDW‐1 and 25–715 J mg AFDW‐1, respectively. Total cost of net construction for an ‘average’ 5th instar larva (2–808 mg dry wt) was 0124 J as silk (75–8 % of total cost) and 0030 J as increased activity over the 293‐minute building period at 15°C.

A significant cost jn net building was demonstrated by larvae which were forced to rebuild their nets daily. They lost more weight than larvae which were forced to rebuild every second day; undisturbed (starved) larvae lost least weight. The weight of nets which were rebuilt daily declined over successive constructions, but net allocation (net weight/larval weight) remained rather constant. The major energetic expense of undisturbed larvae was routine metabolism, whilst that of the daily rebuilders was silk synthesis.

Feeding regime had a marked influence on net construction, and ad libitum fed larvae built larger nets than those fed every second day; starved larvae built the smallest nets. Food capture was apparently linked to the initiation of construction behaviour and thus a more liberal feeding regime was associated with larger nets.

The energy gain (food intake –costs of metabolism and silk synthesis) of ad libitum fed larvae was greater than that of animals fed every second day, and the cost/benefit function for both groups declined throughout the experiment. While each meal was associated with additional net‐spinning costs, over time, the animals tended towards greater energetic economy.

Prior feeding regime had no effect on the weight of nets built subsequently; nets were spun without reference to expectation of prey capture. Prior feeding regime had a significant effect on giving‐up time, and those animals with previous experience of high prey capture rates abandoned nets sooner than larvae which had experienced a lower rate of encounter. However, the giving‐up time of all treatment groups (< 50 % given‐up after 30 days) was longer than previously reported for polycentropodids.

Polycentropus flavomaculatus larvae have resting metabolic rates lower than those of ‘normal’ poikilotherms and spiders, but similar to those of ant lions. These differences are correlated with modes of food capture, and allow P. flavomaculatus to endure periods of food scarcity.
Incubation temperatures, sex ratios and sex determination in a population of Nile crocodiles (Crocodylus niloticus)
Authors: HUTTON J. M.
Published: March 2009

A demographic study of the Nile crocodile Crocodylus niloticus at Lake Ngezi, Zimbabwe, revealed that females predominated in all size classes and among embryos. The sex of C. niloticus was shown to be determined by the temperature of egg incubation in constant temperature laboratory experiments. At 31 °C and below only females were produced. The threshold temperature for maleness was between 31 ° and 34 °C, but appeared to vary between clutches. The duration of the incubation period varied with temperature and was 110 days at 28 °C, falling to 85 days at 34 °C. Incubation temperature affected hatchling length, but not mass. Hatchlings from incubation at 34 °C were shorter on average than those from incubation at 28 °C and 31 °C, but by three months had outgrown them. There was no sex‐related difference in length in a random sample of 200 two‐year‐old C. niloticus on a crocodile farm. Mean temperatures in wild nests were consistently lower than 31 °C and therefore the male threshold as determined in the laboratory. Embryonic development was slow and hatching success poor. The shallowest eggs in a nest had higher mean temperatures and more advanced embryos than the deepest eggs. They also experienced daily temperature fluctuations of up to 10 °C during which the maximum occasionally rose to 35 °C. Constant temperature incubation was not a good model of field conditions, but the correlation between nest temperatures and embryonic sex is consistent with temperature‐dependent sex determination in the wild.
An analysis of the forces of fighting of the blackbuck (Antilope cervicapra) and the bighorn sheep (Ovis canadensis) and the mechanical design of the horn of bovids
Authors: Kitchener Andrew
Published: March 2009

The costs and benefits of fighting in bovids are high in terms of injury and reproductive success, respectively. The breakage of a horn would curtail reproductive success permanently. Therefore, the horns of bovids should include sufficient material so that they are strong enough to be unlikely to break in fighting but without being too heavy to carry around. The forces developed during fighting were measured in a computerized analysis of film of blackbuck and bighorn sheep. All possible modes of failure were investigated using a mechanical analysis to see how the horns are most likely to fail.

The maximum possible force developed during fighting is 3400 N for the bighorn sheep and 456 N for the blackbuck. Bending stress, shear stress, deflection, strain energy and critical crack lengths were calculated for the horns of these two bovids. Horns are most likely to fail in bending as indicated by safety factors. Most of the force is taken in compression due to the curvature of horns. Shear stresses are insignificant and deflections are negligible during the most forceful encounters.

The safety factor in bending of the horn of the bighorn sheep is greater (10) than that of the horn of the blackbuck (3.4) because the forces are probably more variable and unpredictable in the fighting of the former.

All of the energy of fighting is absorbed by the body musculature because horns store less than 1% of the energy produced in fighting as strain energy when they bend. Cracks and scratches mustbe more than 60% of the transverse basal dimensions of horns in order for there to be catastrophic failure at the maximum stresses developed during fighting.

The horns of the blackbuck and the bighorn sheep appear to be minimum weight structures given the variability of the forces acting on them and are unlikely to break in fighting given the forces calculated from the analyses of films.
Homology and evolution of the opercular series in the loricarioid catfishes (Pisces: Siluroidei)
Authors: Schaefer Scott A.
Published: March 2009

Aspects of the morphology of the opercular region of siluroids (catfishes) were examined to determine the homologies of the opercular bones of loricarioid catfishes, a diverse monophyletic neotropical group. Homology of the component structures was inferred by examination of three criteria: (1) functional relations to the jaw abduction mechanism of primitive halecostome fishes; (2) positional relations to the bones of the suspensorium and the path of the preopercular laterosensory canal; and (3) pattern of development of the preopercular canal and lateral cheek plates of loricarioid catfishes. The majority of siluroids have lost one or more of the preopercular canal exit branches to the skin surface present in most primitive siluroids. A number of specializations of the canal pathway and components of the opercular series have occurred in loricariids. Trichomycterids have the preopercular canal reduced to a short branch from the pterotic. Callichthyids share the presence of a preopercular canal with primitive siluroids, but have lost the communication of the canal between the preopercle and pterotic bones. Callichthyids and scoloplacids share one additional loss of a preopercle exit. The second of two subopercular elements of astroblepids is homologous with the interhyal. Astroblepids and loricariids have lost one additional preopercle exit, the interoperculo‐mandibular ligament and the corresponding biomechanical couple for lower jaw abduction. Loricariids have probably lost the interopercle as well. These derived features of loricariids and astroblepids are viewed as specializations for a particular feeding behaviour: scraping algae and detritus from the substratum.
Comparative rates of natural osteological disorders in a collection of Paraguayan birds
Authors: Goodman S. M. , Glynn Carolyn
Published: March 2009

A Series of bird skeletons collected in areas of Paraguay without severe human distrubance were examined for ostelogocial abnormalities. The majority of pathological lesions were the result of tauma and a significant portion to the pectoral girdle. Several groups showed a relatively high prevalence rate, e.g. hawks and owls, which is presumably related to the method of food capture. The interpretation of the results is discussed in regards to zooarchaeological analysis for which it is important to separate natural rates of bone disorder from other potential influences before human‐induced factors can be implicated.
Population biology and estimates of abundance of fruit bats (Pteropodidae) in Philippine submontane rainforest
Authors: HEIDEMAN P. D. , HEANEY L. R.
Published: March 2009

Thirteen species of megachiropteran bats were captured in primary forest at 830–1000 m on Negros Island in the central Phillippines; 1229 individuals were marked and released. Individuals of six species were recaptured, for an overall recapture rate of 13%. For these six species, mean movement distance ranged from 0.16 to 0.75 km. For the two species with larger sample sizes, Haplonycteris fischeri Lawrence and Ptenochirusjagori Peters, adult males moved only one‐half as far as females or subadult males. For three species, Cynopterus brachyotis Muller, H. fischeri and P. jagori, minimum longevities in the wild of four or five years were documented. For the same species, estimates of combined subadult and adult annual survival were 60 to 80%. Density estimates for six species ranged from 0.2 to 3.7 individuals per hectare, with a cumulative density of about 10 bats per hectare. Considerable differences in proportional abundance were found between different subsamples of netted bats, but most of this variation could be accounted for by variation between habitats. Four species (Cynopterus brachyotis, Eonycleris spelaea Dobson, Macroglossus minimus Geoffroy, and Rousettus amplexicaudatus Geoffroy) that were common in agricultural habitats distant from forest were strongly associated with clearings and rare in forest; three species (Harpyionycteris whiteheadi Thomas, Nyctimene rabori Heaney and Peterson, and Ptenochirus jagori) that were as common in clearings as in forest, or slightly more common in clearings, are absent from sites more than a kilometre from forest or forest patches, and appear to use clearings principally as flyways; and one species (Haplonycterisfischeri) that was much more common in forest than in the adjacent clearings is elsewhere present only in or very near forest or in forest patches. Estimates of density of small subcanopy fruit bats that are derived from recapture data were found to be correlated with rank‐order abundance in moderate (c. 100 fruit bats) net‐samples in forest, and directly proportional to abundance of fruit bats in large (c. 300–500) samples in forest. This indicates that large netting samples can provide meaningful estimates of relative abundance for these species.
Social structure of the Eurasian badger (Meles meles): genetic evidence
Authors: EVANS P. G. H. , MACDONALD D. W. , CHEESEMAN C. L.
Published: March 2009

Studies of territorial, highly stable groups of wild Eurasian badger, Meles meles, revealed that more than one adult of each sex may breed within a group, and that extra‐territorial movements may occur within clusters of territories. Although there is some genetic structuring within a local population and a deficiency of heterozygotes, due probably to minimal juvenile dispersal, heterogeneity of gene frequencies is reduced by: (a) adults transferring between adjacent groups, and (b) matings between males of one group and females of another. Marked changes in gene frequencies between generations indicate that a minority of males have a strong influence on the genotypes of the offspring, being either polygynous or promiscuous. Within one generation, the young of a given group may be sired by two or more males, and these males may not necessarily be members of that group.
Two patterns of differentiation in the jaw musculature of teleostean fishes
Authors: GOSLINE WILLIAM A.
Published: March 2009

In its most generalized configuration among modern teleosts the M. adductor mandibulae comprises a single, almost continuous mass of musculature extending from the cheek to the inner surface of the mandible. In more advanced teleosts this muscle is usually divided into sections. Two basically different pathways of differentiation in the cheek part of the adductor mandibulae are dealt with here. One is that in the ostariophysine fishes. The other is represented in at least the great majority of acanthopterygians. Only certain of the differentiated sections are homologous in these two large groups of fishes.
Reproductive strategies of bats in Africa
Authors: Happold D. C. D. , Happold M.
Published: March 2009

The reproduction of 37 species of bats from Malawi was investigated, and the strategies (litter size and chronology) of seven species were determined. Reproduction was then related to rainfall and (if possible) abundance of food. Strategies of Malawian bats were compared with strategies of bats from six other African environments with different patterns of rainfall and availability of food. Monotocous species are numerous and found in all environments, but there are few polytocous species and polytocy has not been recorded in some environments. Ten reproductive chronologies (distinguished by the timing of parturition in relation to season, the presence of reproductive synchrony, the number of pregnancies/year, and the presence or absence of postpartum oestrus) were recognized in African bats. The number and kind of chronologies occurring in different environments is variable. Four chronologies have been recorded in fruit‐bats; intraspecific variability is rare, possibly because fluctuations in the abundance of fruit are comparatively small in the environments where most species of fruit‐bats are found. Reproductive inflexibility may explain why most fruit‐bats do not exploit diverse environments. Eight chronologies have been recorded in insect‐eating bats. These bats show more interspecific and intraspecific variability than fruit‐bats, probably because seasonal differences in the availability of insects are great enough to impose considerable selective pressure on reproduction. Species capable of reproductive flexibility exploit diverse environments.
Implications of the dental eruption sequence in Barbourofelis (Carnivora, Nimravidae) for the function of upper canines and the duration of parental care in sabretoothed carnivores
Authors: Bryant Harold N.
Published: March 2009

The eruption of the large deciduous upper canines in the nimravid sabretooth cat Barbourofelis was delayed until after the individual was eating meat. This inference is based primarily on the eruption sequence and dental wear displayed by seven specimens referred to this genus. It indicates that the sabres were not required for feeding and suggests that these teeth were primarily killing devices. The deciduous upper canines in Barbourofelis and the permanent canines in large felids probably erupted at similar stages of dental ontogeny. If the potential for independence from adults occurs with the eruption of canines that were large enough to serve as killing devices, the delayed eruption of the deciduous sabres in nimravids did not necessitate any significant extension to the long period of parental care that is typical of the extant Carnivora.

The eruption sequence of, and patterns of wear to, the dentition of Barbourofelis demonstrate that juveniles were processing meat before the eruption of the deciduous sabres and thus the upper canines were not necessary for feeding. This supports the view that the sabres were preferentially killing devices; any use of the sabres in dismemberment of the carcass by adults was probably secondary. The transfer of these inferences to felid sabretooths such as Smilodon may be unwise; however, arguments that Smilodon's sabres were inefficient slicing devices (Simpson, 1941), and the patterns of wear on its incisors and cheekteeth (Miller, 1969; Akersten, 1985), suggest that a similar scenario is likely. The marked modifications to the morphology and eruption sequence of the dentition in Barbourofelis may not have resulted in any significant increase in the length of parental care.
Duration of post‐weaning fast and local dispersion in the southern elephant seal, Mirounga leonina, at Marion Island
Authors: Wilkinson I. S. , Bester M. N.
Published: March 2009

Post‐weaning behaviour of southern elephant seals, M. leonina, was studied at Marion Island. Duration of fast in both sexes increased in direct proportion to weight at weaning, while it decreased with weaning date in males. Both sexes appear to fast until they have reached a lower weight ‘threshold’ of around 70% of weaning weight. Local dispersion after the fast was studied by resighting tagged animals at weekly intervals. Only 460 (7.0%) resights out of 6530 involved a move between sites, representing 378 (16.8%) of the 2246 pups that were tagged. Males moved more frequently between tagging sites and covered greater distances than females. Moves between sites are more frequent and distances travelled are greater in December than November. Differences in dispersion patterns between Marion Island and lies Kerguelen may be caused by differences in coastal configuration. Underyearlings spent 105.0±19.6 days at sea before returning for between 10 and 20 days in the autumn. Weaning weight had no effect on likelihood of hauling out in autumn. Movements between sites during the autumn haulout are infrequent and no fidelity to birth site is evident at this stage.
The feeding strategy of a crab spider, Diaea sp. indet. (Araneae: Thomisidae): post‐capture decision rules
Authors: Pollard Simon D.
Published: March 2009

Post‐capture decision rules and the mechanisms and constraints controlling these rules were examined in a New Zealand crab spider, Diaea sp. indet. Diaea envenomates prey, principally in the head and thorax, and injects the total amount of venom it uses to immobilize prey within 15 s of the prey being captured. Diaea injects a larger volume of venom into larger prey, which demonstrates that this species can regulate the amount of venom injected. Diaea usually feeds from two sites on the prey—initially the head, then the posterior abdomen. Prey envenomated in the thorax or abdomen are re‐oriented by the spider so it can begin feeding from the prey's head. During feeding the exoskeleton of the prey remains intact. Diaea initially mixes digestive fluid, secreted from itsmidgut, with the contents of the prey. Fluid is then extracted from the prey using suction provided by the combined action of pharyngeal muscles and a sucking stomach. The sucking phase of feeding generates a pressure deficit (vacuum) within the prey and alternates with a relaxing phase, during which the spider stops sucking and the extracted fluid flows back into the prey. Both the sucking and relaxing phases lengthen as increasing volumes of fluid move between the spider and the prey. Reflux of fluid into the prey allows Diaea to mix digestive fluid with parts of the prey that are not in the immediate vicinity of the spider's mouthparts. Fluid is refluxed at an increasing distance from the spider's mouth as the lengthening sucking phase increases the vacuum within the prey.
A new species of the mite genus Mesoseiulus (Parasitiformes: Phytoseiidae) associated with thrips (Insecta: Thysanoptera)
Authors: Baker Anne S.
Published: March 2009

Mesoseiulus robertsi n.sp. is described from Bactrothrips sp. (Insecta: Thysanoptera) found on dead mango leaves in Cameroon.
Early embryonic development of the grey short‐tailed opossum, Monodelphis domestica, in vivo and in vitro
Authors: Baggott L. M. , Moore H. D. M.
Published: March 2009

Eggs and embryos (up to the unilaminar blastocyst stage) were collected from grey short‐tailed opossums, Monodelphis domestica, at known time intervals after mating. Some were fixed immediately for examination by light and electron microscopy while others were maintained in culture at 37 °C in 5% CO2 in Ham's F10 medium containing foetal calf serum. Cleavage to the early blastocyst stage was obtained in vitro although most embryos displayed arrested development at the eight‐cell stage. From gross morphological and ultrastructural observations a pattern of embryogenesis to the unilaminar blastocyst was constructed. Comparisons were made with the events of early development in other marsupials.

Oocytes were fertilized soon after ovulation and their zonae pellucidae surrounded by a mucoid layer originating from mucopolysaccharide secretion of oviductal epithelial cells. Within 24 hours zygotes passed into the uterus and shell membrane formation commenced.

The early embryonic development in vivo and in culture of the grey short‐tailed opossum, Monodelphis domestica, was investigated by light and electron microscopy. The following timetable of events was constructed:

The first cleavage at about 28 hours after ovulation (54 hours after mating) was at right angles to the equator of the zygote and was accompanied by the vesiculation of yolk mass. The resulting two blastomeres were composed of peripheral polar cytoplasm.

The second cleavage (44 hours) and third cleavage (approx. 72 hours) produced small blastomeres with no cell contact. Yolky vesicles surrounded the blastomeres.

The fourth cleavage division (approx. 96 hours) occurred in the same equatorial plane as the second resulting in two tiers of cells which subsequently flattened against the inner surface of the zona pellucida. Tight junctions formed between adjacent blastomeres.

Unilaminar blastocysts were formed about 5 days after fertilization.

Development in vitro followed a similar time course to that in vivo, however, most embryos were arrested at the 8‐cell stage.
Intrapopulation variation in the diet of the wood mouse Apodemus sylvaticus
Authors: Montgomery S. S. J. , Montgomery W. I.
Published: March 2009

Variation in the diet of wood mice, Apodemus sylvaticus, was investigated in two contrasting habitats, deciduous and coniferous woodland, over 26 months and in 10 additional sites trapped during winter. Stomach contents were categorized as seed, fruit, green plant, root and animal material. Diet was evaluated using the percentage occurrence of each food type. Age and sex differences in diet occurred infrequently. Seed predominated throughout but was especially prevalent in autumn and winter. There was a peak in the incidence of animal material in the spring and early summer. Animal food was generally more frequent in mice caught in conifer plantations than in deciduous woodland during the longer‐term study. Further, mice from the additional coniferous habitats had greater percentage occurrence of animal food than those from the additional deciduous sites. There was a negative, non‐linear association between relative population size and diet in these winter samples. This suggests that spatial variation in numbers of A. sylvaticus is dictated by food availability and density is locally food limited.
Estimating small mammal abundance for predator studies: snap‐trapping versus sign indices
Authors: Village A. , Myhill D.
Published: March 2009

Small mammal abundance was estimated by snaptrapping and sign indices every three months for seven years on two farmland areas in eastern England. Microtus were caught more often than Clethrionomys in both areas, and Apodemus more often in arable than mixed farmland. Clethrionomys apparently produced more signs per vole caught than did Microtus, and year‐to‐year changes in the sign index were better correlated with changes in the Clethrionomys, than the Microtus, snap‐trap index.

When there were few Clethrionomys caught, between‐site variations in the sign index were best explained by variations in the Microtus snap‐trap index, but this was not so when Clethrionomys trap scores increased. Seasonal changes in the production of sign per vole meant that the sign index was a poor indicator of the extent of seasonal variation in the snap‐trap index. The sign index may give an approximate measure of spatial or annual variations in vole abundance where there is only one vole species present, but it gives misleading estimates if more than one species produces signs.
Gestation period and between‐birth intervals in Carollia perspicillata (Phyllostomatidae, Chiroptera)
Authors: Laska Matthias
Published: March 2009

Several aspects of reproduction were investigated in a captive colony of Carollia perspicillata.

The gestation period of four females was found to be 125, 121, 108 and 105 days, respectively.

Twenty‐eight to 32 days post‐partum sexual receptivity seemed to occur in females, as only during this period copulations resulted in pregnancy.

The statistical median of the distribution of between‐birth intervals (B.B.I.) fell into the class of 121–130 days and the shortest B.B.I, was 120 days.

Young bats gave birth for the first time at the age of 381±25 days (mean±S.D.; N = 6), the youngest female being 350 days when she gave birth. Thus female leaf‐nosed bats seem to reach sexual maturity at approximately nine months of age.

The synchronization of sexual activity with seasons that was typical under field conditions was maintained during the first year of captivity, but faded within four years.

The data presented suggest that the females of this colony may exceed the expected pattern of two births per year and at least three females gave birth to eight young within 36 months.

Increase in population density seemed to cause infanticide and a reduction of the number of individuals housed together led to a marked increase in rearing success.
Parturition and early maternal care of spotted hyaenas Crocuta crocuta: a case report
Authors: Henschel J. R. , Skinner J. D.
Published: March 2009

Birth and the early development of spotted hyaenas Crocuta crocuta has been documented for captive animals (Grimpe, 1916; Schneider, 1926; Pournelle, 1965; Golding, 1969) and in the wild (Kruuk, 1972). However, little is known of parturition and maternal behaviour in the first fortnight following parturition. The behaviour of one dam during this critical period is described.
Seasonal changes in populations of three sympatric isopods in a Hong Kong forest
Authors: Ma H. H. T. , Dudgeon D. , Lam P. K. S.
Published: March 2009

Data on the population dynamics of tropical isopods in general, and those inhabiting forests in particular, are scarce. Consequently, the population dynamics of three sympatric isopods, Burmoniscus ocellatus (Philosciidae), Formosillo raffaelei and Orodillo maculatus (Armadillidae), were studied at two neighbouring sites in a mixed forest in Hong Kong between March 1985 and December 1986. Isopod population densities varied with the species, site and season, with mean densities ranging from 100–150 m‐2. Burmoniscus ocellatus and F. raffaelei had a single recruitment peak per year, while O. maculatus had two. Results of the present study revealed that air temperature was the main factor explaining seasonal variations in population density, while rainfall exerted its effect with a two‐ to three‐week time‐lag, depending on the species studied. Approximately 20% of Formosillo raffaelei and O. maculatus sampled were found infected by Rickettsiella bacteria. The possible influence of pathogens, and other biotic factors, on the dynamics of the Hong Kong isopod populations was discussed
Ultrastructure of Holothuria polii encapsulating body
Authors: Cancicatti C. , Quaglia A.
Published: March 2009

The coelomic cavity of freshly collected Holothuria polii specimens contains a variable number of brown pigmented and unpigmented encapsulating structures. They are composed of nodules with entrapped parasites and an internodular mass which comprises a number of nodules. Both brown and unpigmented bodies occur in different size classes depending upon the number of nodules accumulated in a complete body. The unpigmented bodies probably represent an early unmelanized stage of the brown ones.

The nodule was ultrastructurally constituted by foreign bodies surrounded by a fibrous, electron‐dense, non‐cellular layer, probably melanin, followed by a layer of elongated and extremely flattened amoebocytes. Nodules were assembled in an internodular mass formed by amoebocytes type I, II and III spherule cells. As for the amoebocytes constituting the nodule, those present in the spaces between nodules did not develop junctional complexes. It is conceivable that the intricate network established among the cell processes could represent the mechanical force maintaining the whole structure.

As suggested by our results, two functional amoebocyte populations seem to be responsible for the organization of the scavenger body: 1. encapsulating amoebocytes, characteristically non phagocytosing, elongated cells; and 2, phagocytosing amoebocytes. The former organize the nodules, the latter constitute the internodular mass of several nodules.

Most probably, the double scavenger activity justifies the considerable complexity of the H. polii encapsulating structure compared to other invertebrates.

Spherule cells participate only in constituting the internodular mass.
Parasite load and brightness in lizards: an interspecific test of the Hamilton and Zuk hypothesis
Authors: Lefcort H. , Blaustein A. R.
Published: March 2009

Hamilton & Zuk (1982) hypothesized a positive correlation between a species' sexual showiness and its level of parasitic infection. We tested the hypothesis in 26 species of lizards, members of a class of vertebrates never before used to test the model. The prevalence of parasites was determined using published lists of parasites found in wild lizard populations. An index of showiness (brightness) was derived by scoring photographs of lizards in natural settings. Contrary to expectations of Hamilton & Zuk (1982), we found an inverse correlation between a lizard species' brightness and parasite prevalence. No correlation was found between a species' brightness and the number of parasite genera, species, or percentage of individual infecting parasite taxa. These results are discussed in relation to other interspecific tests of the hypothesis.
The breeding season of three species of kiwi (Apteryx) in captivity as determined from egg‐laying dates
Authors: Cockrem J. F. , Goudswaard R. , Sibley M. D. , Fox E. K. , Johnson T. M. , Bell M. J.
Published: March 2009

Records from kiwi (Apteryx spp.) breeding centres were used to obtain laying dates of 403 North Island brown kiwi (Apteryx australis mantelli) eggs, 24 great spotted kiwi (Apteryx haastii) eggs and 25 little spotted kiwi (Apteryx owenii) eggs. North Island brown kiwi outdoors had an annual cycle of egg‐laying with 88.5% of eggs laid from June to January. Eggs were laid in every month of the year, with fewest eggs in April (2.1 % of all eggs). The greatest number of eggs was laid in July (15.6% of all eggs), with a second peak of laying in October (13.5% of all eggs). Both the great spotted kiwi and little spotted kiwi had annual cycles of egg‐laying, with the main egg‐laying seasons being August‐January (87.5% of eggs) for the former and July‐December (96.0% of eggs) for the latter. The highest peaks of laying were in October and August, respectively. Kiwi eggs were considered to belong to the same clutch if they were laid no more than 40 days apart. Clutch size in the North Island brown and little spotted kiwi was most commonly one or two eggs. In the great spotted kiwi only clutches of one egg were found. The mean clutch size of North Island brown kiwi outdoors (1.51±0.05) did not differ from that of free‐living North Island brown kiwi (1.33±0.09). Similarly, there was no difference in the mean clutch size of captive and free‐living little spotted kiwi (1.39±0.14 and 1.10±0.07). The mean interval between eggs for kiwi outdoors did not differ between North Island brown kiwi and little spotted kiwi (27.4±0.5 and 30.7±1.8 days). The results indicate that all three species of kiwi maintain annual cycles of egg‐laying in captivity, with the main egg‐laying season being longer than in free‐living birds.
Activity patterns of termite‐eating land planarians Microplana termitophaga (Platyhelminthes: Tricladida)
Authors: Cumming Meg S.
Published: March 2009

The land planarian Microplana termitophaga is one of three invertebrate predators feeding at the open chimneys of the mound of the termite Odontotermes transvaalensis in Harare. This paper records over 4000 field observations of the mound and reports on the planarians over three rainy seasons from 1990 to 1993. Microplana termitophaga is crepuscular with a large early morning and a smaller evening activity peak. Rainfall appears to be of over‐riding importance; activity is confined to the rainy season, occurring once the cumulative rainfall reaches 150‐250 mm and being suspended during longish dry spells. Activity is also favoured by ambient relative humidity above 70%, light intensity below 50,000 lux (but not total darkness) and ambient temperature between 13 and 23d̀C. Planarians on sun‐exposed, but not on shaded, mounds disappeared after a drought. Dispersal occurs during prolonged wet weather.

Microplana termitophaga occurs with two predatory spider species and a commensal phorid fly and they all utilize the same termites. These four species exhibit temporal separation, probably related to their specific micro‐climatic needs.
The foraging ecology of dhole (Cuon alpinus) in Mudumalai Sanctuary, southern India
Authors: Venkataraman Arun B. , Arumugam R. , Sukumar R.
Published: March 2009

Two dhole (Cuon alpinus) packs were monitored in Mudumalai Sanctuary, southern India, during 1989‐93 to look at population dynamics, movement pattern, and foraging strategy and their inter‐relationship with the maintenance of social groups. Pack size fluctuated substantially (4–18 and 4–25 in the two packs) owing to dispersal and demographic factors such as females not breeding in a given year. Both packs killed a much higher proportion of chital (Axis axis) and sambar (Cervus unicolor) fawns (<one year old) than their availability in the population. There was no correlation between pack size and body weight of prey killed, while per capita consumption of meat declined with increasing pack size. Home‐range area (83.3km2 and 54.2km2 for the two packs) was not correlated with pack size. Pack movement from one resource patch (consisting of resting sites and aggregations of prey species) to another was not random or based on factors such as inter‐patch distance or relative prey densities. There was no difference in mean residence time of the pack across the four resource patches; the pack moved across these in a sequential manner in one direction. We conclude that dholes live in groups not because of any advantages accruing from enhanced group sizes through increased per capita yield of food, but as a consequence of the dispersion of resources.
Habitat relations within lowland grassland rodent communities in Taiwan
Authors: Adler Gregory H.
Published: March 2009

Patterns of habitat use by murid rodents were examined in lowland grasslands in Taiwan. Fifteen grassland sites were live‐trapped in 1990, and 16 microhabitat variables were measured at each of 539 trap stations in the sampling sites. Mus caroli, Apodemus agrarius, Rattus losea, and Bandicota indica were captured regularly during the sampling. Rattus norvegicus and Nivivenrer coxingi were captured infrequently. The analysis focused on the four common species.

Mus caroli, R. losea, and B. indica have been considered to be commensals of humans and to be largely dependent upon agricultural crops. However, these species were captured in natural habitats, often far from agricultural areas. M. caroli and R. Iosea were by far the most abundant species.

Vertical stratification of the habitat did not increase the number of species or overall rodent abundance. Rather, sites with well‐developed grass cover and little vertical development of vegetation above the grass layer had the highest overall densities of rodents.

Use of habitat was very similar among the four common species and was concentrated in areas with dense grass cover. Overlap in habitat use was particularly extensive in the core areas of greatest occupancy. Relative population abundances (number of individuals captured per trap station) of the four species were related weakly to the microhabitat variables. These variables were better predictors of capture probabilities of M. caroli and R. losea at individual trap stations, as revealed by multiple logistic regression. Abundances and capture probabilities did not appear to be affected by the presence or abundance of other species.

It is suggested that body size differences may facilitate coexistence of these four species of ecologically similar murids. Beginning with the smallest species (M. caroli), body masses of each subsequent species in the series differ by at least a factor of two. These grassland communities may be somewhat resistant to invasion by more similar‐sized species of murids.
Description of the first complete skeleton of the extinct New Zealand goose Cnemiornis calcitrans (Aves: Anatidae), and a reassessment of the relationships of Cnemiornis
Authors: Worthy T. H. , Holdaway R. N. , Sorenson M. D. , Cooper A. C.
Published: March 2009

The discovery of the first essentially complete Cnemiornis calcitrans skeleton is reported. This has facilitated a description of features of the skeleton not previously described and a reassessment of the phylogenetic relationships of Cnemiornis. A morphological comparison is supported by a cladistic analysis to show that Cnemiornis is the sister taxon of Cereopsis novaehollandiae. The data set based on morphological characters was insufficient to resolve the issue of whether the Cnemiornis/Cereopsis clade was the sister taxon of the rest of the Anserines or more primitive than them. The anserines (geese and swans) are the sister group to Dendrocygna, Thalassornis, and all other anatids. A 96 base pair sequence of mitochondrial DNA is reported for Cnemiornis calcitrans which shows much similarity with the equivalent section in Cereopsis, and is considerably different from other anserines. The DNA sequence supports the inclusion of the Cnemiornis/Cereopsis clade within the Anserinae.
Trophic consequences of differential performance: ontogeny of oral jaw‐crushing performance in the sheepshead, Archosargus probatocephalus (Teleostei, Sparidae)
Authors: Fernandez L. P. H. , Motta P. J.
Published: March 2009

Studies in the field of ecomorphology aim to delineate the role of anatomy in determining an organism's ecological niche. Although an extensive literature exists correlating trophic morphology with biological role, surprisingly little research has investigated the causal relationship between morphological variation and differential feeding performance. This study examines the possible role of oral jaw‐crushing performance in moulding diet in an ontogenetic series of sheepshead, Archosargus probatocephalus (Sparidae: Teleostei). By comparing potential niche, as determined by anatomical predictions of force production, with realized niche, as determined by field studies investigating prey use in the natural environment, we were able to assess to what degree maximal capabilities affected resource use. Evidence strongly suggested that oral jaw‐crushing force was an important determinant of diet in these fishes. All oral jaw elements, as well as force produced by the adductor mandibulae complex, scaled with positive allometry, which was consistent with the increase in hard prey taken. There was a significant correlation between increased force production and increased durophagous habit. Lastly, the force used to feed in nature increased at the same rate as the predicted maximum force generated by the adductor mandibulae complex. Studies such as this one speak directly to the relationship between maximum functional potential and actual patterns of resource use.
Factors influencing use of freshwater pools by otters,Lutra lutra, in a marine environment
Authors: Lovett L. , Kruuk H. , Lambin X.
Published: March 2009

Eurasian otters (Lutra lutra) inhabiting a marine environment need to wash in freshwater in order to maintain the insulating properties of their fur. Use of freshwater pools by otters on the coast of Skye was studied in order to determine factors influencing pool choice. A number of characteristics were recorded for all pools present. Otter spraints were recorded as an indication of pool use. Only 34% of available pools were utilized by otters. Stepwise logistic regression revealed that choice of pools is influenced by pool depth, the percentage of a pool's substratum composed of flat rock, and the surrounding percentage cover of short grass. Possible reasons for these associations are discussed. The information may be of use when selecting and managing coastal areas for otter conservation.
Secondary poisoning of mustelids in a New Zealand Nothofagus forest
Authors: Alterio N. , Brown K. , Moller H.
Published: March 2009

Eleven radio‐tagged stoats (Mustela erminea) and one weasel (M. nivalis) died of secondary poisoning following Talon 20 PTM (20 ppm brodifacoum) poisoning operations which killed mice (Mus musculus), ship rats (Rattus rattus) and probably brushtail possums (Trichosurus vulpecula) in a New Zealand beech (Nothofagus) forest. This poisoning method could be an especially useful way of restoring New Zealand native bird populations because it kills several predator species in one operation. Potential unwanted side‐effects must be researched before its routine use. This research also demonstrates the potential hazards of second‐generation anticoagulant rodenticides to conservation of rodent predators in Europe.