摘要:

A new genus of long‐snouted, eubrachythoracid arthrodire,Camuropiscisgen. nov., is described from the Upper Devonian Gogo formation of Western Australia. It is represented by two species, the typeC. concinnussp. nov. andC. laidlawisp. nov. These species are interchangeable withCoccosteusspp. in a sketch cladograin for arthrodires; their phylogenetic relationships are not known in any detail.C. concinnushas a well‐preserved pelvic girdle and throws new light on the structure of this element in arthrodi

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01102.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Mortality of life stages ofPhyllonoycterspecies in mined leaves of oak and birch was investigated in a Cheshire locality during 1974.Phyllonotycterspecies are mostly bivoltine, butP. cavellais univoltine. Parasitism and host‐feeding (predation) by Hymenoptera caused most mortality. Parasitism was heaviest in the first generations, with ectoparasitism predominating, although endoparasitism caused inore mortality in the second generations. The incidence of host‐feeding increased to leaf‐fall when more mines contained host‐fed remains than either parasites or healthyPhyllonoycter. Host‐feeding occurred particularly in the first three (sap‐feeding) larval instars; ectoparasitism affected mainly the two subsequent (tissue‐feeding) larval stages and pupae; and endoparasitism occurred in all stages although affected hosts are killed only from the fourth larval instar onwards. Highest mortality was suffered by tissue feeders in the first generation but by sap feeders in the second. Total mortality was greatest in second generation mines and, in a given generation, survival curves forPhyllonotycterwere similar on both tree species. The observed density of second generation mines relative to first in the sample was higher than predicted from first generation mortality levels, and this

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01103.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Parasitic Hpenoptera attackingPhyllonorycterspecies mining leaves of oak and birch were studied at a Cheshire locality during 1974. The host developmental stages killed, and attacked, by each parasite species are analysed. Smaller species and males tend to kill earlierPhyllonorycterinstars than do larger species and females, and certain of the endoparasites as well as the ectoparasites must discriminate between small hosts which receive haploid eggs and large hosts which receive diploid eggs. Host‐feeding is very widely practised, and facultative hyperparasitism is engaged in by all except the braconids and a few specialized chalcids. The biology of a parasite species generally allows its allocation to one of three groups according to the size of host larva that it attacks, whether it is endoparasitic or ectoparasitic, whether or not the host continues to develop after parasitization, the extent of its hyperparasitic behaviour, its reproductive capacity, and the width of its host range. Different strategies, together with different specific host and habitat preferences, provide the basis for parasite complexes of high species diversit

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01104.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The tictors affecting the variation of shell colour morph frequencies of the intertidal snailLittorina rudisMaton have been examined using ordination and correlation techniques. The major gradient underlying variation in shell colour is related to habitat type and structure. Dark, patterned shells are characteristic of cliff and salt marsh habitats whilst light, unpatterned shells reach high frequencies on boulder shores. Colour morphs do not differ significantly in shell thickness and between‐shore variation in colour morph frequencies cannot be directly attributed to habitat dilterences in the risk of shell injury, but to other factors associated with habitat type and structure, e.g. parasitism. It is suggested that the maintenance of shell colour polymorphism inL. rudisis probably mediated by selection on pleiotropic characters rather than shell colour alon

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01105.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Echinoderes andamanensissp. nov. is described from the Andaman Islands (Bay of Bengal, Indian Ocean). Unlike most members of this genus, this new species lacks middorsal spines. It is further distinguished by the presence of lateral spines on segments 4, 10 and 11 in the female and 4, 10–12 in the inale. Collected withE. andamanensiswere specimens ofE. ehlersipreviously known only from a single specimen collected in 1885 in Zanzibar. The Andaman Island females have shorter spines than the males. Additional species includeCatena gerlachi, previously known only from Walcair, India. A single juvenile exuvium ofPynophyessp. was also found. The taxonomic relationships of the species and other members of the genus are discusse

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01106.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01102a.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY