摘要:

Calyptozetes sarekensis, an oribatid mite found predominantly, though not exclusively in lichens, inhabits regions within the arctic circle and subarctically between latitudes 60oand 70o(Swedish Lapland, Norway, Bear Island, Spitzbergen, Jan Mayen, Iceland, Greenland, northern Canada). In recent years, however, the species has been recorded from a number of montane sites in Great Britain and southern Europe. There would appear to be only two possible explanations for die discontinuous distribution of this mite. (1) The species has been transported from its main arctic and subarctic area of distribution to its southern montane outposts by some agent (driftwood, birds, wind), or (2) in Britain and southern Europe it represents a relict species of the Ice Age, left stranded on high ground after the final retreat of the ice. Evidence is presented in support of the second hypothesis. In addition, it is suggested that its presence on the different land masses of its main arctic and subarctic range, which are separated from each other by wide stretches of ocean, could be explained by die hypothesis that it is a very ancient species daring from the time Laurasia was in existence some 60 or more million years ago. The alternative hypothesis of transportation of the species between one or more of these areas, however, is by no means ruled out.

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1979.tb00047.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Movements of brown rats were deduced from records made during a capture‐recapture study of rural populations on two farms in Mid‐Wales. Populations in the hedges were sampled at monthly intervals for two years, but samples from the farm buildings were obtained only irregularly and by a variety of methods.On the main trap line, of the rats captured during at least two sampling periods 35 (78%) females and 57 (74%) males appeared to have established home ranges, the best estimates of mean home range length for each sex being 54.8 m and 66.1 m respectively. The longest recorded distances travelled during known life were 850 m for a female and 954 m for a male, although the median distances travelled were only 43 m and 52 m respectively. The median distance travelled during a sampling period (seven nights) was about 24 m for both sexes. There were no significant differences between the distances travelled by the sexes or by different age groups, and there was little seasonal variation.Infestations in the hedges were always associated with streams, and those more than about 100 m from the buildings seldom persisted through winter. During autumn and winter the rats in the more distant localities tended to move towards the buildings, but there was no suggestion of an orderly migration. Twenty‐seven out of 386 rats marked in the hedges were recovered amongst 576 taken from the buildings, but only nine of diem had travelled more than 100 m. No rats released in the buildings were captured in the hedges. Rats established in the buildings seemed to exclude rats immigrating from the h

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1979.tb00048.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Data are presented on the type‐material representing the species described by Linnaeus in his generaSphex, Chrysis, Vespa, ApisandMutilla, The names here considered total 158; six are currently applied in the Hymenoptera Parasitica. Of the balance of 147, three are emendations and five are unavailable homonyms or names proposed in the synonymy of other species. Fifteen Linnaean names are here placed as synonyms. One name is attributed to an author other than Linnaeus, and live names remainspecies incertae sedis.The remainder, 118, are applied as valid names in die Hymenoptera Aculeata. Holotype specimens in London, Uppsala or Stockholm represent 60 names; 55 names are based on lectotype specimens of which 49 are here designated, two by other authors. One name is represented by a neotype specimen in Lund, and one by a lectotype figure. One non‐aculeate species is based on syntypes. Specimens appear to be lost with respect to 25 names; three specimens in Uppsala may be the holotypes of a further three species.Eight new combinations are made, and twelve new synonyms established; three further new combinations and three further new synonymies are suggested. A systematically arranged summary of species treated and of nomenclatural changes made is given. Nomenclatural changes affecting non‐Linnaean names are included where relevant; lectotypes are designated for two non‐Linnaean

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1979.tb00049.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

In some wading birds (Charadrii) each adult rears a brood alone. The female leaves her first clutch with her first mate before herself rearing a clutch fertilized by a second male, who is already tending its first mate's first clutch. We here develop a simple model to account for the exchange of mates between clutches, and relate it to reported field studies. We suggest that females are attempting to be polygamous, rather than simply bigamous. Provided a female has a chance of obtaining a second, unmated male and that the costs of leaving the first male before remating are not high, matechanging will be favoured over monogamy. The implications of this model to the evolution of the more usual forms of polyandry and of male‐like females are discusse

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1979.tb00050.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1979.tb00047a.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY