摘要:

Cases of the larvae of the caddis flyPotamophylax latipennis(Curtis) (Trichoptera) were collected from a 60 m stretch of the River Allander, Milngavie, Dunbartonshire, Scotland. Water depth ranged from 2 to 25 cm and water speed from 0·25 to 0·66 m/sec. The river bottom consisted of gravel and stones lying on a compact silt substrate. The size of the stones ranged from under 1 cm to 22 cm in diameter. Larval cases were only found on the undersurfaces of large stones of a diameter 11 cm to 22 cm, and were not limited to any particular shape of stone. Analysis of the microdistribution of larval cases on the undersurfaces of the large stones revealed two levels of aggregation. Firstly, cases were found only on particular stones, and secondly, they were aggregated on particular areas of the undersurfaces of those stones. These aggregations may be the result of gregarious behaviour, or be caused by certain large stones and particular areas of the undersurfaces of those stones having the most suitable microenvironment for attachment. Cases usually faced into the current. A short description of the larval case is give

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb01724.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

The mating calls of three members of the “regularisgroup” of toads (Anura: Bufonidae) that are sympatric in part of South Africa are examined. A naturally occurring population of hybrid toads from Pretoria (South Africa) has previously been described as representing an intergrading betweenBufo garmaniMeek andBufo rangeriHewitt. Examination of the mating calls of these toads provides little evidence of intergrading betweenBufo rangeriandBufo garmani, and indicates the involvement ofBufo regularisReuss in the hybridization. The mating calls of the hybrids are varied, and are structurally intermediate between those of the parental species. Mating call parameters are found to be useful in separating forms that are difficult to distinguish on morphological grounds alone. They are further found to be a sensitive non‐morphological means of ascertaining the affinities of naturally occurring hybrid

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb01725.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Polymorphism in the cerci of the earwig (Forficula auriculariaL.) has been re‐examined making use of a graphical method for the analysis of frequency distributions. Three statistically distinct types of male cerci and two statistically distinct types of female cerci are describe

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb01726.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Two surveys are described which were designed to provide information on changes in status in the British Isles of the frog (Rana temporariaL.) and the toad (Bufo bufoL.). Questionnaires were distributed asking for information and conclusions are based on replies referring to 1079 localities and 314 individual breeding sites. Replies indicated that the frog decreased slightly over most of the British Isles during the 1940s and 1950s, and suffered considerable declines over most of England throughout the 1960s. Moderate declines occurred in Scotland and Northern Ireland during the last half of the decade. Declines for the toad probably followed a similar pattern.The garden pond was the only habitat in which either species increased. Both the frog and the toad decreased markedly in breeding sites on agricultural land in the early 1960s, but during the late 1960s declines were less severe.The main reason for the declines has probably been loss of suitable wetland habitat due to sites being filled in, drained or physically modified in some way. Insecticides are only likely to have been harmful in sites where unusually high pollutant concentrations occurred. Other possible contributory factors are discussed and of these road mortality is perhaps the most important. Recent declines for the frog were significantly related to human population density.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb01727.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

On hatching from the egg, a larva ofLepidosroma hirtumCurtis constructed a tubular, sand grain case. As the larva became older it periodically added new material to the anterior of the case and, once in every instar except the 1st, cut off ⅓ to ¼ of the posterior of the case. In the 3rd instar the larva changed from adding sand grains to cutting out and attaching almost rectangular leaf panels. By the 5th instar the case was composed entirely of leaf panels. The case was then square in section and composed of one row of panels for each of the sides. The panels were not truly rectangular but convex on the leading edge and sides and concave at the back, so that the anterior convexity of one panel fitted into the posterior concavity of the panel in front. Panels were arranged with their long axes across the case. The seams between panels in the roof were half a panel length out of phase with those in the sides but in phase with those in the floor. The convex sides of a panel allowed it to overlap the seams between panels on the two adjacent sides. If a 5th instar larva was removed from its case it first built a sand grain case followed by a leaf panel case. The animal cut panels from the leaf with its mandibles and then further shaped them by chewing round the edge. Just prior to pupation, the case was modified by the attachment of further panels to the anterior; these included panels which for the first time in the life of the larva were arranged with their long axes along the ca

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb01728.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Details of the segmental chaetotaxy of the legs of 47 species of Uropodina are given. On the basis of the ontogenetic development of the chaetotaxy, the Uropodina may be divided into two groups which coincide with the concepts of the Lower (Polyaspidoidea) and Higher (Uropodoidea) Uropodina of certain authors. Chaetotactic criteria do not support the classification of the Polyaspidini and TrachyuropodinisensuHirschmann and Z‐Nicol within the Oplitinae Hirschmann&Z‐Nicol, the Diarthrophallini within the Uroactiniinae Hirschmann&Z‐Nicol or the genusTrachyteswithin the Uropodini.A critical appraisal is given of the classification of the Uropodidae (based on “Gangmerk‐male”) by Hirschmann

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb01729.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Records of pinnipeds and sirenians are rare in the western Indian Ocean away from continental coasts. In the case of pinnipeds there are apparently no records at all in this area, except for occasional stray Elephant sealsMirounga leoninaas far north as Mauritius and Rodriguez, and a single record of an undetermined species in the southern Maldive Islands: the Indian Ocean now lacks any counterpart of the Monk seals of the Caribbean and the Pacific (King, 1956, 1964). In the case of sirenians, Dugongs are widely distributed round the continental coasts of the Indian Ocean, including Madagascar, the Comoros, and Ceylon, but there is much less information concerning them on more remote Indian Ocean islands. This paper draws attention to hitherto unnoticed reports of animals which could be either pinnipeds or sirenians made by 18th and early 19th century navigators, and reviews some of the published evidence for the existence of these animals in the 17th and 18th centuries in the Mascarene Islands. It is shown that many of the reef islands of the tropical western Indian Ocean were formerly inhabited by seals, of undetermined species and now extinct, and that some of the early references to Dugongs in fact concerned seals.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb01730.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

The morphology of the Millerettidae is described in detail, based on careful preparation using the acetic acid technique. This shows that the Millerettidae constitute a closely knit natural group and results in a more satisfactory classification. Common to the group is the possession of anthracosaur‐like vomerine fangs. A second feature of major importance is that these animals do not have a solid lower temporal bar. It is suggested that the reason for this is to be sought in an understanding of cranial kinesis. The reason for the lack of a temporal bar can be traced back to Anthracosaurian amphibia and is due to expansion and contraction across the cheek region during jaw movements. (These movements were necessarily minimized during the transition from amphibian to reptile.) Following from this it is suggested that the Millerettidae may have given rise directly to the Squamata. The Archo‐sauria and Rhynchocephalia probably had an entirely independent origin. Only three genera are considered valid, viz.Miileretta(Broom, 1948) in which the temporal opening first appears,Millerosaurus(Broom, 1948) in which contact between jugal and quadratojugal is lost, though the jugal retains a crenellated posterior edge, and a new genusMilleropsisbased onMillerosaurus pricei(Watson, 1957) in which there is still greater separation between jugal and quadratojugal and in which the posterior border of the jugal is quite smo

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb01731.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY