摘要:

The timing of milk production in Antarctic fur seals was studied at Bird Island, South Georgia. Like all lactating otariid seals (Pinnipedia: Otariidae), Antarctic fur seal females alternate between short nursing periods ashore and regular foraging trips to sea. Females do not necessarily return to the colony with full mammae, which indicates that mammary volume capacity is unlikely to limit foraging trip duration. Upon arrival at the colony, milk fat (r2= 0.33, P<0.04) and protein (r2= 0.60, P<0.002) content were positively correlated to the time spent at sea. A similar trend was observed in the milk produced on land. The rate of milk energy production was much lower at sea (5.02 ± 0.05 MJ day‐1) than on land (23.66 ± 4.4 MJ‐1day‐1). The rate of milk energy production during the foraging trip was negatively correlated to the time spent at sea (r2= 0.29, P<0.05), whereas the rate of milk energy production on land was positively correlated (r2= 0.61, P<0.001) to the duration of the preceding foraging trip. The total amount of milk energy delivered to the pup during each twoday nursing period was positively correlated (r2= 0.60, P<0.002) to the duration of the previous foraging trip. The overall rate of milk energy delivery, however, was independent of foraging trip duration. This accords with previous observations that the growth rates of Antarctic fur seal pups are unaffected by maternal foraging trip duration p

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02741.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The semi‐fossorial scincid lizard,Lerista bougainvillii, is oviparous throughout its extensive range in south‐eastern mainland Australia. However, two widely separated (by approximately 1000 km) island populations are viviparous; in these populations the eggshell is lost and females retain their offspringin uterountil embryogenesis complete. One mainland population in south‐eastern Victoria shows an intermediate condition, in which the eggshells are incomplete and uterine embryogenesis is prolonged.Morphological and electrophoretic analyses confirm a high degree of morphological and genetic similarity between populations (i.e. there is no evidence for the presence of more than one species), and phenetic analyses of these data show that each of the two disjunct viviparous populations more closely resembles adjacent oviparous populations than the other viviparous group. Hence, we infer that viviparity may have arisen twice withinL. bougainvillii, in both cases on offshore islands with a cold cl

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02742.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Spitting' behaviour was examined in selected taxa ofNajaandHemachatus.A description of the kinematics and variations of spitting in each species was generated from the analysis of videotape records of over 400 spits. Interspecific variation was noted in the spitting behaviour. Intraspecific variation ranged from very stereotypic spitting inN. siamensis, andH. haemachatus, toN. pallidaandN. mossambicain which every aspect of the behaviour was variable. A striking lunge and exhalant burst of air may occur as part of the spitting behaviour, but are not essential agents in venom spitting.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02743.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Three new species are described in the cheilostomate bryozoan genusSchizoporellaHincks, 1877. British records of Scliizoporella dunkeri Reuss are shown to represent two previously unnamed species.Scliizoporella dunkeriis the senior synonym of the Adriatic speciesSchizoporella longirostrisHincks. Material ofS. longirostrisfrom British localities is referred in part toS. dunkeriand in part to a previously unnamed species.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02744.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Field vole abundance was assessed on a range of upland habitats in spring and autumn, using live—trapping, snap—trapping and vole sign index methods. Three estimates of vole numbers were derived from live—trapping, five from snap—trapping and one from vole signs. Estimates were compared using a correlation matrix in order to establish the most accurate and consistent method. Snap—trapping for five nights provided enough information to calculate vole density, though the method was time consuming. Vole abundance indices derived from two nights' snaptrapping were significantly correlated with indices from five nights' trapping. Live—trapping and vole sign index were discounted as methods for this study area, as both proved

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02745.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Japanese macaques on Yakushima Island have been seen attempting to open thick, woody plant galls in order to eat aphids contained within them. We analysed a sample of galls and gall fragments with toothmarks and found that 22% were still intact indicating a failure to open them. These marks were examined and measured. Ten pits had a mean indentational area of 1.44 mm2(S.D. 0.28 mm2), while 15 elongated scratches had a mean width of 1.26mm (S.D. 0.27 mm). The gall resembled a light wood in its mechanical properties and had a microhardness of 80.4MPa. Assuming that at least two marks were formed in any given bite, indentational analysis gave a mean estimate of bite forces of 232N (maximum 291 N) to produce pits and 255 N (maximum 487N) to produce scratches. These forces are consistent with, but at the high end of, limits predicted by anatomical analysis.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02746.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The spatial organization of the rare Ethiopian wolf (Canis simensis) was studied in the Afroalpine heathlands of Bale Mountains National Park, southern Ethiopia, between 1988 and 1992. Nineteen animals were radio‐tracked, 48 ear‐tagged and 64 others recognized by coat patterns and observed directly. Dry season (October—March) home ranges of resident wolves covered between 2 and 15 km2. The ranges of adult males were slightly larger than those of females, and subadults' home ranges were slightly smaller than those of adults. The population density of the wolves was correlated with prey biomass. In optimal habitat, wolves lived in packs of 3—13 adults (mean 5.9 wolves>1year old) containing several close‐kin males; adult sex ratio favoured males 1.88: 1 and combined pack home ranges averaged 6.0km2. In an area of lower prey productivity, wolves lived in pairs or small groups (mean 2.7), adult sex ratio was 1:1 and home ranges averaged 13.4 km2.Home ranges overlapped extensively (mean 85%) between members of the same pack. Four to seven percent of the population was additionally composed of non‐resident females, inhabiting larger ranges (mean 11.1 km2). Home ranges of neighbouring packs were largely discrete, forming a tessellating mosaic of packs occupying all available habitat. Pack home ranges were stable in time, drifting only during major pack readjustment after the disappearance of a pack or significant demographic changes. Ethiopian wolf home ranges were smaller than would be expected for a carnivore of its size and sociality, presumably as a result of the high rodent productivity of the Afroalpin

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02747.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

In order to examine a previously hypothesized influence of selective hunting on allele frequency changes at some regularly polymorphic allozyme loci in red deer (Cervus eluphus), antler characters, serving as criteria for culling, were examined in relation to electrophoretic variation in two free‐ranging populations of the Vosges, Eastern France, and an enclosure in Central France. When homozygous for the alleleIdh‐2125, stags ≥ 2 years old had a significantly higher number of antler points (NAP). When homozygous for the alleleAcp‐2100, stags older than 5 years had antlers that were significantly larger for a number of traits (NAP, main beam length and circumference, coronet circumference, brow tine length). Among younger stags, all antler traits inAcp‐2100homozygotes were significantly smaller than in carriers of the alternative allele,Acp‐285. Our data suggest the presence of at least two independent genetic components (one associated with early development of a high NAP, the other with generally large antler size in adults), affecting antler expression in red deer. Those genetic components, possibly major genes which are chromosomally linked with the allozyme loci studied, compensate or reinforce each other in their phenotypic effects. By playing a role in balancing benefits and costs of male reproductive success, they may be part of a genetic mechanism enabling the rapid adaptation of a population to various environmental and demographic conditions. The three populations studied originate from one another, and, based on an assessment of effective population sizes, it could be demonstrated that selective hunting for antler shape has changed allelic frequencies at the associated marker loci within a few

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02748.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

An investigation of the phylogenetic relationships of a number of cartilaginous fish based on the use of the immunological properties of the iron‐binding serum protein, transferrin. is presented. Data on immunological distance and the rate of amino acid substitution are used to produce a dendrogram. The tree confirms the close relationships of the holocephalan species examined which are a sister group of other neoselachians. The tree also indicates that the squaloids and galeoids are separate groups and thatHeterodontusbelongs with the galeoids. It is also clear that the divergence between the squaloids, galeoids (includingHeterodontus) and the Holocephali is an ancient one and that the rajids probably diverged from this basal stock rather than any more recent squaloid/squatinoid/galeoid groupin

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02749.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Three hundred and eighty‐two moles,Scalopus aquaticus, were collected from 16 sampling grids located within a 23 km2area in South Carolina, USA. Age of moles was determined using tooth wear. Both the mean and median ages of trapped moles werec.two years; the oldest mole was in its seventh year of life. More than 50% of the individuals are estimated to die during the first six months of life; adult survivorship was relatively high and age‐dependent. There was differential mortality between the sexes, and females lived longer than males.Scalopus aquaticusin South Carolina livedc.1.2 times longer than the maximum lifespan predicted on the basis of body mass. Pooled samples of moles yielded the expected age distribution, with fewer individuals occurring in successively older age classes. However, based on bootstrap estimates of the variance in age structure, samples from some grids contained significantly more young or old individuals than expected due to sampling error. Mole populations appear not to be in demographic equilibrium at this local scale, but instead conform more closely to a metapopulation‐type of stru

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb02750.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY