摘要:

A cytogenic study of nearly 200 house mice(Mus musculus sensu stneto)and aboriginal mice(Mus hortulanus, Mus abbotti)of the subgenusMuswas carried out. Mice were sampled from most localities in the former U.S.S.R., from the western borders to the Far East, and it was shown that it is possible to use cytogenetic markers to classify the species and rare subspecies of the subgenus. Such markers included the characteristic morphology of the sex chromosomes and the pattern of distribution of the C‐heterochromatin in the karyotype. Thus, the aboriginal mice, together withM. spretus, are characterized by a significant reduction in the size of the Y chromosome. In addition, the variant of the X chromosome (so called‘molossinus’lype) previously only observed in JapaneseM. in. molossinuswas found in all theMus musculussampled from the fauna of the former U.S.S.R. Another type, the so called‘domeslicus’is a plesiomorphic variant of the X chromosome which is normally found inM. domestuus. M. hortulanus, M. abbottiand possibly inM. spretus.The presence of the common variant X chromosome in the house mice of the various subspecies in the fauna of the former U.S.S.R., Mongolia(raddei)and Japan(molossinus)provides the basis for the integration of Asian house mice into the one species,At. musculus sensu stricto.The problems of morphology, ecology and systematics of the mouse fauna of the former U.S.S.R. are also discussed with special attention being paid to the studies of the so called‘

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1993.tb00881.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Patterns of variation in chromosomes, mitochondrial DNA and allozymes were assessed for two parthenogenetic(Lepidodactylus lugubrisandHemidactylus garnotii)and one sexual(H. frenatus)species of house gecko that have colonized remote Pacific Ocean islands. The aims were to test the assumed recency of colonization and to provide information on the amount and distribution of genetic variation.Lepidodactylus lugubriswas found to have diploid and triploid clones, high heterozygosity and moderate diversity for allozymes, and only two common types of mtDNA. The common clones distinguished by genetic analysis were geographically widespread. Together the genetic data suggest multiple origins ofL. lugubris, with multiple recent invasions of the Pacific Ocean islands.Hemidactylus garnotiihad low genetic diversity for chromosomes, mtDNA and allozymes. In contrast, its sexual congener,H. frenalus, had unusually high levels of mtDNA diversity, with some widespread variants. The low level of mtDNA diversity in the parthogenetic species provides strong support for the assumption that these are recent colonists of Pacific Islands.

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1993.tb00882.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The radular teeth of 55 species of Sacoglossa (= Ascoglossa) (Mollusca: Opisthobranchia) with known diets are classified into three basic groups: triangular, blade‐shaped and sabot‐shaped. Cell wall composition of the food plant is the single most important factor influencing radular morphology. The algae eaten by sacoglossans have either xylan, mannan or cellulose as their structural wall component. Sabot‐shaped teeth are associated with diets of Siphonocladales and Cladophorales, which have cellulose cell walls of a ‘crossed fibrillar texture’. Triangular teeth with lateral denticles are associated with diets ofCaulerpaor with calcified algae. Most of these have xylan as the major structural polysaccharide. Blade‐shaped teeth occur in a large number of species representing a wide variety of diets. It is proposed that the three types of teeth function in different manners. Tooth denticulation is correlated with functional group of the food plant. The radular teeth ofElysia viridisfeeding onCodiumare longer, wider and have more curved tips than teeth ofE. viridisfeeding onChaetomorpha.The teeth ofE. viridistransferred fromCodiumtoChaelomorphain the laboratory change in shape as w

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1993.tb00883.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

In a recent review article by Mani published in 1990, it was shown that the changes in the frequency of the morphcarbonariacan be explained through a migration‐selection model and the model is capable of reproducing the decrease in thecarbonariafrequency since the enactment ofClean Air Acts.In this paper new data both forcarbonariaand forinsulariaup to 1990 for West Kirby in NW England and for Cambridge are presented. In the earlier review, the data for West Kirby extended to 1987 and for Cambridge to 1985. Data not previously published for thecarbonariaand theinsulariafrequencies at sites in Northwood in Middlesex, Egham in Surrey and Ringwood in Hampshire are also presented. A migration‐selection model was used to predict the change in the frequencies of the melanic morphs up to the year 2010. All the data are compared with the predictions of the model. It is encouraging that the data follow the theoretical predicti

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1993.tb00884.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

We review published studies in which arthropods were presented with a choice of food types at a range of relative densities. Twenty‐four of 28 studies showed frequency‐independent preference; 11 studies also showed frequency‐dependent preference. Both pro‐ and anti‐apostatic selection were found. In the light of these studies we discuss possible behavioural mechanisms which produce such selection; the potential benefits to the predators and the consequences of such selection for diversity both within and betwee

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1993.tb00885.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY