摘要:

The changing temperature requirements ofChesias legatellaSchiffermüller during embryonic development are investigated. The eggs are laid in the autumn and embryogenesis is interrupted by a short diapause at the germ band stage, after which development proceeds slowly throughout the winter. The effects of temperature during the pre‐diapause, diapause and post‐diapause phases of development are assessed by examination of the rate and variability of morphogenesis through all the embryonic stages. An examination is presented of the effect of temperature during the late autumn on the rate and uniformity of diapause termination, and consequently on the length of the hatching period the following sp

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb04099.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The reported occurrence of protozoan parasites of the blood of British wild birds and mammals is reviewed. Nineteen species of British birds have been recorded as hosts ofHaemoproteus(orParahaemoproteus), Leucocytozoon(orAkiba), Plasmodium, Trypanosomaor “atoxoplasms” (a group whose taxonomic status is presently in doubt), and seventeen species of British mammals are known to be hosts ofBabesia, Hepatozoon, PolychromophilusorTrypanosoma(including at least three species from Chiroptera:T. (Schizotrypanum) dionisii, T. (S.) vespertilionisandT. (Megatrypanum) incert

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb04100.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

A study of the breeding season of the polymorphic equatorial land snailLimicolaria martensianaSmith (Achatinidae: Pulmonata) lasting six years and six months in populations in the Kampala District (lat. 0 20′) and the Equator line shows that the snail breeds continuously throughout the year but has bimodal peaks in its breeding which occurs during the dry seasons, while during the rainy seasons breeding is low. It is the decrease in the amount of rainfall which induces peak breeding and as a result there is an inverse relationship between the amount of rainfall and the breeding intensity. The evolution of ovoviviparity with the ability to retain eggs and/or youngin uteroduring aestivation is the phenomenon that enablesL. martensianato have peak breeding during the dry seasons. Moisture which enables young to feed and thus grow is an ultimate factor in determining breeding inL. martensiana. The gestation period is 10 to 14 days during the rainy seasons but the snail retains its eggs and/or youngin uteroduring the dry seasons and only deposits them when rain returns. The eggs take 18.6±5.43 days (N=130) to hatch after they are laid. Hatchingin uteroand outside occurs by the young eating the egg shells. Oogenesis in the snails occurs at all times.L. martensianastores viable allosperms which it can use for further reproducti

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb04101.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Sticklebacks from a variety of habitats have been examined for trichodinids. Two species of trichodinid were found on fish at every site. They were identified asTrichodina domergueisubsp.domergueiandT. tenuidens, and these identifications are discussed in relation to previous observations by other workers. The tolerance to change in salinity has been examined for both species and the activity of the contractile vacuole ofT. domergueihas been examined in detail.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb04102.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The surface area of the gills, air sacs and skin have been measured in specimens of different body size and their relationship to body weight fits the equation: area=aWb. The slopes (b) of the double logarithmic plots are 0.746 (gills), 0.662 (air sacs) and 0.684 (skin). The gills are poorly developed and their average weight specific area is less than figures obtained for sluggish marine fishes. The skin has an area about 70% of the total respiratory surfaces (gills+air sac+skin). Nevertheless the greater thickness of the skin leads to a smaller diffusing capacity of the tissue barrier (Dt) as compared with the gills and air sac. The air sac area for each ml of air that it contains is about 10.5 cm2which is much lower than figures obtained for lungs of other air‐breathing fish and for tetrapod

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb04103.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Five populations of marmots were studied in Colorado from 1962 through 1972. Males are classified by age as yearlings, two‐year olds, and adults. Socially, marmots are colonial, peripheral, or transient. Each population was divided into four age‐sex classes, male yearlings, female yearlings, male adults, female adults, for analysis of social behaviour. Social behaviour was amicable or agonistic. Both types of behaviour occurred between male yearlings and each of the other age‐sex classes. Play‐fighting characterized social behaviour among male yearlings. Agonistic behaviour characterized social interactions between male yearlings and male adults. Male yearlings avoided male adults and usually dispersed from the locality. Adult male aggression enhanced but was not necessary for dispersal of yearling males. Agonistic behaviour between males and the four age‐sex classes was not related to population density.Territorial males are conspicuous and advertise their presence by tail flagging. Many colonial males patrol their territory. Adult male social behaviour is predominantly agonistic. Mean rates of amicable and of agonistic behaviour between adult males and adult females were greater for years of male turnover than for years of male returns.Territoriality is characterized by exclusive use of the area by the colonial male, vigorous defence against transient or peripheral males, and by a relatively fixed area. A decrease in the number of males in an area causes an increase in the size of territories. Additional males in an area causes a decrease in the size of territories. The mean size of 24 typical territories is 0.67 ha. Reduction in the number of territories in an area was associated with increased agonistic behaviour among adult males. Fights were rare and occurred when the territorial system was unstable.The major functions of the territorial system are enhanced reproduction in a limited environment, enhanced outbreeding and enhanced fitness of colon

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb04104.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The methods of principal component analysis and of canonical analysis are applied to data of the external measurements of the Sperm whale(Physeter catodon).The principal component analysis summarizes the main features of the data in the first four components and suggests those characters of prime importance while the canonical analysis permits comparisons between those whales caught at several locations.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb04105.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY