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131.
Sexual selection in a monomorphic lek-breeding bird: correlates of male mating success in the great snipe Gallinago media 总被引:2,自引:0,他引:2
Summary In the lek-breeding great snipe, male morphology, behaviour, and territory features were recorded for individually marked birds on two adjacent leks. Partial correlation sshowed that male mating success, expressed as the number of female solicitations and copulations, was negatively correlated with the distance of a display territory to the lek center and positively correlated with the number of displays per unit time given by a male. No other variables were directly correlated with male matin success. Thus, central males obtain more matings than peripheral males and successful males display more per unit time than do less successful males, independently of position on the lek. Central males were found to be older than peripheral ones and were present more often on the lek. Furthermore, central males had a larger number of white tail feathers, which are usea as visual signals in the displays, but this may be explained by the fact that these males were older. It is suggested that male great snipe are subject to sexual selection mainly in behavioural and vocal cues and that this may explain the absence of size and plumage dimorphism in this species. 相似文献
132.
Arne Stahl 《Die Naturwissenschaften》1996,83(10):459-466
133.
Coevolution is defined as specialized relationships between species that lead to a reciprocal evolutionary change. A particularly
suitable model system for studying coevolution is the interactions between obligate avian brood parasites and their hosts.
The common cuckoo (Cuculus canorus, hereafter cuckoo) is a well-known brood parasite, which utilizes a range of smaller passerines as hosts. However, warblers
of the genus Hippolais have rarely been reported as being victims of cuckoos, and furthermore, few data exist on the occurrence of antiparasite
defenses in these hosts. In this study, we examined possible host–parasite coevolution between cuckoos and eastern olivaceous
warblers (Hippolais pallida elaeica, hereafter olivaceous warblers) in three closely situated areas in northwestern Bulgaria. The olivaceous warbler has never
been reported to be a regular cuckoo host. However, the present study, carried out in 2001–2003 shows that the olivaceous
warbler is regularly and heavily parasitized by the cuckoo in this area. Parasitism rate was high (26.6%, 34/128) and consistent
among years, with some variation between areas. The cuckoo egg mimicry was moderately good, and olivaceous warbler rejection
rate of such eggs was 50%. Cuckoo eggs laid in olivaceous warbler nests had a whitish to whitish-green ground color, and the
majority appeared to be distinctly different from cuckoo eggs found in other host species in the area. The olivaceous warbler
proved to be a rather good host for cuckoos as 20.6% (7/34) of cuckoo eggs laid produced fledglings, a breeding success comparable
to other suitable hosts in Europe. This is the first in-depth study of brood parasitism in a warbler of the genus Hippolais, and cuckoos parasitizing olivaceous warblers probably represent a previously unknown gens. 相似文献