摘要:

Males of aculeate Hymenoptera differ in the behavioural adaptations employed to locate and secure mates. The ecological and evolutionary bases of these differences are explored in this paper. Male bees and wasps search for females by patrolling widely within emergence‐nesting areas or within patches of flowers attractive to conspecific females, or by waiting at landmarks, at specific emergence sites, or at nests. Nest dispersion, flower distribution, the type of female mating system and the nature of male‐male competition appear to be key factors in determining the mate‐locating behaviour of males. Of special interest in multiple‐mating by females, which may be an evolutionary response to the costs of attempting to resist copulation in certain situations. When polyandry occurs, males are under selection pressure to be the last male to copulate with a female prior to oviposition if sperm precedence occurs. In species in which females mate just once, a selective premium is placed on being the first male to reach a virgin female. In either case, because receptive females are a limited resource, there is intense competition among males for access to the resource. The density of competitor males may play an important role in determining whether holding a relatively restricted territory is preferable to the strategy of patrolling widely at various sites which may have females. Territoriality is practiced by males of several species of aculeate Hymenoptera when the number of male competitors is relatively few in number and the distribution of emergence sites or foraging areas of females is clumped i

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1978.tb01075.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Paracryptops spinosus, a new centipede species from Delhi, is described. The species is unique in the genus in that its anal legs have their femora and tibiae beset distally with extraordinary spines. It is pointed out that the exceedingly short poison claws supposed to be incapable of meeting in the middle cannot be depended upon to identify the genusParacryptops. This character is apparent, not real and should be discarded. It is also pointed out that the number of tibial teeth used as a key character at species level, being subject to age variation, can be of limited taxonomic value and should be used with caution.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1978.tb01076.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

In the following account, detailed investigations are carried out on the cyto‐morphological changes in the anterior pituitary (adenohypophysis) of the Indian domestic fowl (Desi fowl)Gallus domesticusduring various growth phases including laying and broody period

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1978.tb01077.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Six species of genusClarias(Clariidae) ‐Clarias angolensisSteindachner,Clarias liberiensisSteindachner,Clarias submarginatusPeters,Clarias laevicepsGill,Clarias walkeriGünther andClarias longiorBoulenger — are redescribed from type specimens. It is shown thatC. submarginatusandC. laevicepsshould be properly ascribed to the subgenusClarioidesDavid and not to subgenusAllabenchelys(Boulenger), and that converselyC. walkeribelongs to subgenusAllabenchelysrather than subgenusClarioides. It is further shown that C.longiorhas commonly been mistaken forC. laevicepsand thatC. walkerihas often been mistaken forC. submarginatus. A general revision of the genusClariasin Africa based on reference to type material is strongly recomme

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1978.tb01078.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY