摘要:

IndividualViviparus georgianusfrom a New York population are iteroparous, maturing in their second year. Ovoviviparous females have a maximum lifespan 1 year longer than that of males (4 + versus 3+ years), though individuals of both sexes can be reproductively active for three consecutive years. Embryophores are carried over winter and released each spring. Female survivorship is positively size related, as is incremental growth within any year. Reproductive effort is age related, increasing from 5.3% for modal 2‐year females to 79.7% for modal 4‐year females. Reproduction is size limited in 2‐year females, no females below 16 mm shell length were found containing broods. The lack of observable survivorship penalties related to reproduction may result from reproductive females have greater biomass and hence greater survivorship. Spat size is positively correlated with female age irrespective of female size, though brood numbers increase with maternal size and growth rates. Caged experiments have shown spat born early to older females grow fastest. Data presented indicate that the young of older females have greater expected lifetime fecundity and fitness. In this population, 3‐year females produce approximately 50.0% of each new cohort, with 2‐year and 4‐year females producing 21.0% and 26.0% respectively. Matrix models of the natural population and modified hypothetical populations emphasize the importance of survivorship and early reproduction in such stable, age‐structure

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01739.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Populations of three branching Caribbean demosponge species are composed of clones produced by asexual fragmentation. Dispersal of the fragments before they become established as independent individuals scatters clone members widely and intermixes members of different clones, complicating study of the clone structure of these populations and contrasting with many other sessile clonal organisms. Clone structures of these populations were inferred using a combination of tissue‐compatibility relationships and an analysis of variations in morphology and colour. Although tissue compatibility cannot be used for precise identification of sponge clones, in general, patterns of variation in morphological characters influencing fragmentation and patterns of fragment dispersal and recruitment suggest that, in these populations, tissue‐compatibility relationships closely reflect clone structure. Conditions that must be met in order to use tissue compatibility for study of sponge clones are discussed, and previous results, from which conflicting conclusions have been drawn, reconciled in this context. Variations among clones in numbers of physiologically independent members and in size and shape of areal extent are discussed in the context of processes that may affect evolution of clonal characters in these populations and in other species that propagate by dispersing asexual fragme

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01740.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A systematic review of parasitological data pertaining to the phylogeny of hominoid primates revealed considerable internal consistency and congruence with non‐parasitological data. Hylobatids are supported as the sister‐group ofPongo + Pan + Gorilla, the ‘Great Apes’. Within the Great Apes,Pan + Gorillaare sister taxa. Multiple analyses of presence/absence data placeHomowith cercopithecids, probably an artefact of humans' widespread occurrence and polymorphic feeding and living habits. Explicit phylogenetic hypotheses are available for only two parasite groups. Hookworms of the genusOesophagostomumsubgenusConoweberiaplaceHomoas the sister‐group ofPan + Gorilla, whereas pinworms of the genusEnterobiusplaceHomoas the sister‐group ofPongo + Pan + Gorilla. This disagreement among data sets with regards to the placement ofHomo, combined with the complete agreement about the placement of the other hominoids, is consistent with uncertainties in current findings from other s

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01741.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Genetic diversity and structure of populations of the wild progenitor of barley,Hordeum spontaneum, from three countries, Israel, Turkey and Iran, in the Near East Fertile Crescent, are compared and contrasted. The analysis is based on electrophoretically discernible allozymic variation in proteins encoded by 27 shared loci in 2125 individuals representing 52 populations of wild barley. The results indicate that: (a)H. spontaneumin the Near East Fertile Crescent is very variable genetically; (b) genetic differentiation of populations includes some clinal but primarily regional and local patterns often displaying sharp geographic differentiation over short distances; (c) the average relative genetic differentiation (Gst) was 54% within populations, 39% among populations, and 8% between the three countries; (d) allele distribution is characterized by a high proportion of unique alleles (51%), and a high proportion of common alleles that are distributed either locally or sporadically; (e) discriminant analysis by allele frequencies successfully clustered wild barley of each of the three countries (96% correct classification); (f) a substantial portion of the patterns of allozyme variation in the wild gene pool is significantly correlated with the environment and is predictable ecologically, chiefly by a combination of humidity and temperature variables; (g) natural populations of wild barley are, on the average, more variable than two composite crosses and land races of cultivated barley. The spatial patterns and environmental correlates and predictors of genetic variation ofH, spontaneumin the Fertile Crescent indicate that genetic variation in wild barley populations is not only rich but at least partly adaptive and predictable by ecology and allozyme markers. Consequently, conservation and utilization programmes should optimize sampling strategies by following the ecological‐genetic factors and allozyme markers as effectively predictive guideline

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01742.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The closely related species of leafhoppers,Oncopsis flavicollis(L.) and0. subangulata(Sahl.), are restricted to birches,Betula pendulaRoth andB. pubescensEhrh., as host plants. Morphometric discriminant analyses of adult insects from S Wales showed O.flavicollispopulations from the twoBetulaspecies to be significantly different. The best discrimination was provided by characters of the male dorsal abdominal apodemes. Analyses of such apodeme morphology in populations more widely from S Britain showed three distinct types: in western localities type 1 dominantly onB. pubescens, type 2 dominantly onB. pendulaand type 3 absent; in eastern localities type 3 only onB. pendula, type 2 on both species ofBetulaand type 1 only onB. pubescens.Acoustic calling and courtship signals of males showed clear differences between the three apodeme types of0. flavicollis.It is concluded that the three0. flavicollistypes, together with0. subangulata, are distinct but very closely related biological species. Contrary to earlier suggestions, this example provides no evidence for host plant utilization polymorphisms.

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01743.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Book reviewed in this article:Flowers of the Himalaya, by Oleg Polunin and Adam Stainton.A Guide to the Vegetation of Britain and Europe, by Oleg Polunin and Martin Walters.The Experimental Biology of Bryophytes,edited by A. F. Dyer&J. G. Duckett.A Birdwatcher's Miscellany,edited by Rob Hume.The Moths and Butterjlies of Great Britain and Ireland,Volume 10, Noctuidae (Part II) and Agaristidae, edited by J. Heath.Atlas of Butterjlies in Britain and Ireland,by J. Heath, E. Pollard&J. A. Thomas.Colour Identification Guide to Butterjlies of the British Isles,revised edition by T. G. Howarth.The World of Butterjlies,An Illustrated Encyclopaedia, by V. Sbordoni&S.Forestiero.Colour Identijcation Guide to Moths of the British Isles,by Bernard Skinner.The Biology of Buttegies,edited by R. I. Vane‐Wright&P. R. Ackery.Australian Grasses,by Nancy T. Burbidge, revised by Surrey W. L. Jacobs.Collins Guide to Grasses, Sedges, Rushes and Ferns,by R. Fitter&A. Fitter. Collins.Grasses of the Soviet Union,by N. N. Tsvelev, edited by A. A. Fedorov.The European Garden Flora,Volume 2, Monocotyledons (Part ZZ), edited by S. M Walters et al.Grasses,3rd edition, by C. E. Hubbard, revised by J. C. E. Hubbar

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01744.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY