摘要:

The chelicerate order Schizomida is represented in Western Australia by a single species,Schizomus vineiHarvey, from caves in the semi–arid Cape Range on the North West Cape peninsula.Schizomus vineioccurs in eight of 170 caves known from the range but is found only in areas where the relative humidity exceeds 92%. The schizomids are associated with a rich fauna (at least 11 species) mostly of detritivores, some of which show troglobitic adaptations. They prey on the cave animals that feed on detritus and are known to eat oniscoid isopods, millipedes, cockroaches, worms andS. vinei.The size class structure of the population in cave C 118 was strongly skewed negatively suggesting that the smaller size classes occupy interstices of the infill of sumps. Schizomids in this cave were found to be distributed at random up to the third nearest neighbour. The minimum population size, with 95% confidence, was estimated to be 1323 individuals.Schizomus vineigrew very slowly in vivaria. One female produced nine eggs which did not survive.Schizomus vineihas a high mean rate of water loss (470–4 mg g‐1h‐1) and a low resistance to water loss (15–2 cm sec‐1); their resistance is about 10 x greater than that of a free water surface, but is about two orders of magnitude lower than that of some spiders and scorpions.Schizomus vineiexcretes a clear fluid and may be ammonotelic.Allozyme electrophoresis strongly suggests that individuals from the different caves are of the same species. Consideration of climate, age of separation of the caves and the general biology of the schizomids suggests that those caves containing schizomids ma

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02481.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Male rock elephant shrews,Elephantulus myurus, showed active spermatogenesis throughout the year but had significant reductions in testis and prostate size, the proportion of interstitial cells and sperm numbers and viability from April to June, when no pregnant females were recorded. Rock elephant shrews have relatively small testes and extragonadal sperm reserves compared to many similar–sized mamma

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02482.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The fine structure of the tail skin oflarvalNeoceratodusforsteri, between stages 40 and 50 (Kemp, 1982), is described and where applicable specific cellular components are compared and contrasted with comparable ones in the skin of adult dipnoans, teleosts and larval and adult amphibians.The epidermis of the early developing tail, within the range studied, differentiates a variety of different cell types. Surface epithelial lucent and vacuolated lucent cells and basal cells are distinguished, and goblet (mucous) cells, Merkel cells and macrophages appear in the epidermis towards the end of the series.Below a poorly developed collagenous basement lamella, immature melanophores with premelanosomes are present, and likewise there are non–myelinated nerves, some striated muscle fibres, capillaries and mesenchymal fibroblasts.The tail epidermis is innervated by naked neurites from the beginning of the series, and the earliest recognizable Merkel cell is in synaptic association with neurite

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02483.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Male and female strategies were compared for wild–living populations of coypu(Myocastor coypusMolina) censused during two years in marshlands of central–west France. In a habitat composed of a canal network bisecting pasture fields typically 0–5 ha in size, coypu movements were largely restricted to stretches of open water, though males explored further from water than females. Adults occupied home ranges with a mean size of 3–82 ha or 1. 19 km of canal, males on average moving faster over a larger area and using a greater length of canal than females. Movements within partially shared ranges were most positively coordinated between male–female pairs, while male–male interactions were less frequent. Juvenile coypus were largely absent from the late winter population. Synchronization of litters in March–April resulted in a peak of juveniles in early summer. The sex ratio of juveniles and sub–adults reversed from a male bias in summer to a female bias in autumn. Population densities peaked in November at 4 ha, with a significant female bias (1M: 1–6F). In the same month, a neighbouring population at lower density (1 ha‐lafter treatment with rodenticide) was significantly male biased (2–7M:lF) and may therefore have been acting as a sink for males dispersing from the high density population. Transients comprised 63% of the population. Females were resident longer than males, 22% of females remaining at least 5 months against 6% of males. Dispersal was recorded only for males aged 6 months or older. The general result, of exploratory behaviour amongst males contrasting with the establishment of longer term home ranges by females, is discussed in terms of male reproductive success and the capacity for females to influence nutrient su

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02484.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The area and inter–trap distance of small mammal live trapping grids can seriously influence observed movement patterns and estimates of animal densities. This paper examines inter–trap movement (ITM) according to inter–trap distance, time of the year, weather and numbers captured for the wood mouse,Apodemus sylvaticus, and the bank vole,Clethrionomys glareolus, in an oak wood in southern England. The analysis is based on live trapping data collected in three studies over an eight–year period. Trap spacing affected inter–trap movement, including the statistic, ‘Mean Distance Moved’ between successive captures (MDM), of different species and sexes of rodents in different and predictable ways. No association was found in MDM between males and females of the same species, MDM and time of the year or MDM and weather. However, there was a weak negative association between MDM and numbers captured, particularly in mice. Using an independent method of assessing effective grid area, the usefulness of the MDM in correcting grid areas for the estimation of animal densities

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02485.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Nocturnal activity of six Indian crested porcupines(Hystrix indica), inhabiting two nearby dens in the Negev desert highlands of southern Israel, was monitored for nine months by radio location telemetry. From movement simulation of 1121 relocations (187 ± 56 per animal) on a grid representation of the 20 km2study area, mean home ranges (i.e. 90% domains) were 1–5 ± 0–4 km2and the animals moved 2.8 ± 0.7 km per night. Spatial activity differed by main foraging habitat which, in turn, corresponded to den affiliation. Porcupines that foraged regularly on crops had narrow domains with bimodal activity centres near the den and in potato fields; and their movements were relatively stable across seasons. Animals dependent on natural forage had larger and seasonally variable domains, and more diffuse dispersions with a single activity centre near the den. Home range overlap was greater among crop foragers, and all porcupines remained closer to dens during moonlit periods. We conclude that crested porcupine dispersion patterns are flexible, and strongly linked to forage availability. The array of analytical procedures used here are recommended for future studies of animal spatial ac

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02486.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Male red–necked wallabies established dominance relationships by fighting, and dominance rankings among males were positively correlated with body size. Females became outstandingly attractive to males during the week preceding mating, and males, who normally ranged widely and solitarily in search of mates, gathered in groups around such females. It is suggested that females, by prolonging their advertisement of oestrus, and thereby inciting sustained competitive interactions among the males who were attracted to them, contributed to a bias in the distribution of male mating success in favour of very large dominant individuals. High–ranking males mated within discrete but undefended areas of absolute dominance (‘dominions’). Direct interactions between dominion–holding males were rare, but males just below dominion–holding status often fought with one another, and were frequently harassed by domin

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02487.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Seasonal changes in the distribution and composition of common seal haul–out groups were followed in a study area in Orkney, Scotland. A marking programme was also undertaken, using both conventional and radio–tags, to study individual movements between sites and seasonal changes in site–use. Certain haul–out sites were used only in the breeding season, while others were used during the winter. Seals were seen at one site all year round and at another during only the pre–pupping and moult period. On one island where two sites were used during the summer, there were significant differences in the sex ratio of groups at the two sites: at one site males predominated and few pups were seen; on another, nearby, mothers and pups were regularly seen, although the site was also used by males. There was also evidence for segregation of the sexes outside the breeding season. Repeated observations of marked seals showed that seals used several different haul–out sites throughout the year, and that the seasonal changes in abundance at different sites resulted from individual changes in site–use. These changes in site–use are discussed in relation to feeding movements, breeding requirements and the physical characteristics of

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02488.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Experiments have been carried out to determine whether cross–fertilization, multiple insemination and sperm sharing occur inBulinus cernicus.Snails collected from Canal La Paix, Mauritius, were found to be polymorphic for glucose phosphate isomerase, and from this stock three snail colonies homozygous for GPI 2/2, GPI4/4 and GPI6/6 were selected. Thus, three markers were available to monitor cross–fertilization. Isolated snails produced egg–masses by self–fertilization 40 days post–hatching. Egg–masses produced by self–fertilizing individuals tended to be smaller than those from cross–fertilizing snails, 367 eggs per egg–mass as opposed to 5–34. The majority of snails (70%) switched rapidly to cross–fertilization after pairing. Multiple insemination by two partners was common, heterozygous progeny were produced in a random manner and did not reflect the sequence of mating. No evidence of sperm sharing was found, snails were found to be capable of passing on their own sperm while still producing eggs fertilized by sperm received from an earlier mating. Differences in mating behaviour were noted between snails representing the homozygous GPI colonies, with snails from one colony adopting the female role more readily than those from the other two, which predomi

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02489.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The value of faecal analysis for estimating the composition of the diet of stone curlews was assessed by examination of the faeces of a captive bird fed on a measured diet. Remains of soft–bodied prey were under–represented in the faeces but the results could be adjusted to allow for this. Estimation of the size of prey was possible by measurement of remnants such as earthworm chaetae and insect mandibles. In some types of prey large specimens left more remnants than small ones and a correction was devised to allow for this. Regurgitated pellets contained large, hard remains and there was no trace of some important prey types such as earthworms. A method is described for estimating the composition of the diet of the wild stone curlews from counts of prey remains in their fae

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1989.tb02490.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY