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001-es BibID:	BIBFORM022625
Első szerző:	Pap Péter László (ökológus)
Cím:	Host-symbiont relationship and abundance of feather mites in relation to age and body condition of the barn swallow (Hirundo rustica) : an experimental study / Péter László Pap, Jácint Tökölyi, Tibor Szép
Dátum:	2005
Megjegyzések:	We analyzed the host-symbiont relationship and factors determining the abundance of feather mites among individual barn swallows (Hirundo rustica L., 1758) in two different host populations during the breeding season and postbreeding period. By experimentally removing the feather mites from the flight feathers of the birds with an insecticide, we showed that these symbiotic organisms have neither harmful nor beneficial effects on the fitness of the host, supporting the view that mites are commensals. This was indicated by the lack of any difference in the change in wing-feather length, tail-feather length, fluctuating asymmetry in tail-feather length, breeding performance, and survival of the birds between the fumigated and control groups 1 year after the experiment. During the postbreeding period juveniles harbored fewer mites than adults and the difference was also significant between the 1-year-old birds and those over 1 year old in the breeding population. The number of mites did not change after the second year of life of the birds. We hypothesize that the difference in abundance of mites between the age classes can be explained by the low reproductive potential of the mites, which are not able to populate the exploitable space until the second year of life of the host. Alternatively, young birds might provide fewer resources than old birds. The significant negative association between the number of mites and the laying date of female barn swallows seems to support the conclusion that the abundance of mites is condition-dependent. Because there was no relationship between other condition indices for males and females and number of mites, further research is needed to confirm this conclusion.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Canadian Journal of Zoology. - 83 : 8 (2005), p. 1059-1066. -
További szerzők:	Tökölyi Jácint (1984-) (biológus) Szép Tibor
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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001-es BibID:	BIBFORM096003
035-os BibID:	(Scopus)84999027902 (WOS)000396964700012
Első szerző:	Tökölyi Jácint (biológus)
Cím:	Resource allocation and post-reproductive degeneration in the freshwater cnidarian Hydra oligactis (Pallas, 1766) / Tökölyi Jácint, Ősz Zsófia, Sebestyén Flóra, Barta Zoltán
Dátum:	2017
ISSN:	0944-2006
Megjegyzések:	Freshwater hydra are among the few animal groups that show negligible senescence and can maintain high survival and reproduction rates when kept under stable conditions in the laboratory. Yet, one species of Hydra (H. oligactis) undergoes a senescence-like process in which polyps degenerate and die after sexual reproduction. The ultimate factors responsible for this phenomenon are unclear. High mortality in reproducing animals could be the consequence of increased allocation of resources to reproduction at the expense of somatic maintenance. This hypothesis predicts that patterns of reproduction and survival are influenced by resource availability. To test this prediction we investigated survival and reproduction at different levels of food availability in 10 lineages of H. oligactis derived from a single Hungarian population. Sexual reproduction was accompanied by reduced survival, but a substantial proportion of animals regenerated after sexual reproduction and continued reproducing asexually. Polyps belonging to different lineages showed differences in their propensity to initiate sexual reproduction, gonad number and survival rate. Food availability significantly affected fecundity (number of eggs or testes produced), with the largest number of gonads being produced by animals kept on a high food regime. On the other hand, survival rate was not affected by the amount of food. These results show that survival is conserved at the expense of reproduction in this population when food is low. It remains a question still to be answered why survival is prioritized over reproduction in this population.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Cnidaria Food availability Life history Senescence Survival/reproduction trade-offs
Megjelenés:	Zoology. - 120 (2017), p. 110-116. -
További szerzők:	Ősz Zsófia Sebestyén Flóra (1993-) (biológus) Barta Zoltán (1967-) (biológus, zoológus)
Pályázati támogatás:	NTP-EFÖ-P-15 Egyéb János Bolyai Research Scholarship of the Hungarian Academy of Sciences Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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