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001-es BibID:	BIBFORM018803
Első szerző:	Pap Péter László (ökológus)
Cím:	Increase of feather quality during moult : a possible implication of feather deformities in the evolution of partial moult in the great tit Parus major / Péter L. Pap, Zoltán Barta, Jácint Tökölyi, Csongor I. Vágási
Dátum:	2007
Megjegyzések:	Here we investigate the change in feather quality during partial post-juvenile and complete post-breeding moult in great tit Parus major by measuring the change in the number of fault bars and feather holes on wing and tail feathers. Feathers grown during ontogeny usually are of lower quality than feathers grown following subsequent moults at independence. This is reflected by higher number of fault bars and feather holes on juveniles compared to adults. Fault bars are significantly more common on tail and proximal wing feathers than on the distal remiges, indicating a mechanism of adaptive allocation of stress induced abnormalities during ontogeny into the aerodynamically less important flight feathers. On the contrary, feather holes produced probably by chewing lice have a more uniform distribution on wing and tail feathers, which may reflect the inability of birds to control their distribution, or the weak natural selection imposed by them. The adaptive value of the differential allocation of fault bar between groups of feathers seems to be supported by the significantly higher recapture probability of those juvenile great tits which have fewer fault bars at fledging on the aerodynamically most important primaries, but not on other groups of flight feathers. The selection imposed by feather holes seems to be smaller, since except for the positive association between hatching date, brood size and the number of feather holes at fledging, great tits' survival was not affected by the number of feather holes. During post-juvenile moult, the intensity of fault bars drops significantly through the replacement of tail feathers and tertials, resulting in disproportional reduction of the total number of fault bars on flight feathers related to the number of feathers replaced. The reduction in the number of fault bars during post-juvenile moult associated with their adaptive allocation to proximal wing feathers and rectrices may explain the evolution of partial post-juvenile moult in the great tit, since the quality of flight feathers can be increased significantly at a relatively small cost. Our results may explain the widespread phenomenon of partial post-juvenile moult of flight feathers among Palearctic passerines. During the next complete post-breeding moult, the total number of fault bars on flight feathers has remained unchanged, indicating the effectiveness of partial post-juvenile moult in reducing the number of adaptively allocated fault bars. The number of feather holes has also decreased on groups of feathers replaced during partial post-juvenile moult, but the reduction is proportional with the number of feathers moulted. In line with this observation, the number of feather holes is further reduced during post-breeding moult on primaries and secondaries, resulting in an increase in feather quality of adult great tits.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Avian Biology. - 38 : 4 (2007), p. 471-478. -
További szerzők:	Tökölyi Jácint (1984-) (biológus) Vágási Csongor István Barta Zoltán (1967-) (biológus, zoológus)
Pályázati támogatás:	OTKA T046661 OTKA NF061143
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM013407
Első szerző:	Pap Péter László (ökológus)
Cím:	Seasonality in the uropygial gland size and feather mite abundance in house sparrows Passer domesticus: natural covariation and an experiment. / Péter L. Pap, Csongor I. Vágási, Gergely Osváth, Cosmin Mureşan, Zoltán Barta
Dátum:	2010
Megjegyzések:	The seasonal change, i.e. the marked differences between seasons of low and high productivity, in the abundance ofectosymbionts and the defence intensity of the host against pathogens is a well defined characteristic of temperate zoneorganisms. Here we investigate the seasonal variation in the uropygial gland size and the abundance of Proctophyllodesfeather mites on the wing feathers of house sparrows Passer domesticus in two breeding populations. The size of theuropygial gland varied significantly in male and female house sparrows over the annual cycle. The gland was small duringthe non-breeding and mating season, after that it started to grow sharply, reaching its maximum size during breeding.Females had larger gland volumes than males during breeding, and the increase in gland size during breeding was morepronounced in females than in males. The number of feather mites was the lowest during breeding, followed by anincrease during moult and reaching its maximum between the wintering and mating seasons. The absence of a significantrelationship between the uropygial gland size and the abundance of feather mites, after controlling for potentialconfounding variables, supports the view that gland oils do not regulate the number of mites. To investigate further thishypothesis, through a full factorial experimental design we tested the effect of uropygial gland and photoperiodmanipulation on the population size and population dynamics of feather mites. The manipulation of uropygial gland hadno effect on mites, supporting our observational results. As a result of the experimentally increased day-length, theabundance of feather mites on wing feathers decreased significantly and more sharply than in the control group,supporting the previous anecdotal evidence about the photosensitivity of these organisms. Using photoperiodic cues,feather mites may respond to seasonal changes that affect their life-history and population dynamics.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Avian Biology. - 41 : 6 (2010), p. 653-661. -
További szerzők:	Vágási Csongor István Osváth Gergely (1985-) (biológus) Mureşan, Cosmin Barta Zoltán (1967-) (biológus, zoológus)
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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Saját polcon: