Jorg Brun

Influence of extra-pair paternity on parental care in great tits (Parus major)

The extent of parental care should usually increase with the benefits expected in terms of reproductive success. In monogamous birds, parental care should therefore increase with brood size. Some recent studies failed to show such a relationship, and we wondered if this may be due to phenomena like extra-pair copulations and/or intraspecific brood parasitism, that could lead to nestlings which are unrelated to one or both putative parents. Thus, measuring the expected benefits by counting the nestlings may be misleading. In our study on parental care in the great tit (Parus major) we determine parentage via multilocus DNA fingerprinting and show that parental care (measured as anti-predator nest defence) seems to be adjusted to the number of offspring fathered by the resident male rather than to the total number of nestlings.

Reproductive success of monogamous and polygynous pied flycatchers (Ficedula hypoleuca)

Abstract One of the most interesting aspects of the mating system of pied flycatchers is the regular occurrence of polygyny. Here we present data on the reproductive success of polygynously paired pied flycatcher males compared to monogamous males based on paternity analyses through DNA fingerprinting. Males paired with two females suffered a higher loss in reproductive output per female compared to monogamous males due to (1) a greater proportion of unhatched eggs in their broods, (2) greater nestling mortality and (3) a greater probability of being cuckolded. Nevertheless, the number of fledglings was significantly greater for polygynous males. Based on the number of nestlings that returned for subsequent breeding seasons, however, the reproductive success of monogamous and polygynous males did not differ significantly. These data raise the question as to why males attempt polygyny.

High frequency of extra-pair paternity in the Coal Tit

Haemoproteus columbae. Trans. R. Soc. Trop. Med. Hyg. 66: 186-187. Marshall, A. G. 1981. The ecology of ectoparasitic insects. Academic Press, London. Moller, A. P. 1990. Effects of a haematophagous mite on the Barn Swallow (Hirundo rustica): a test of the Hamilton and Zuk hypothesis. Evolution 44: 771-784. Moller, A. P. 1992. Parasites differentially increase the degree of fluctuating asymmetry in secondary sexual characters. J. Evol. Biol. 5: 691-699. Moller, A. P. 1994. Sexual selection in the Barn Swallow (Hirundo rustica). IV. Patterns of fluctuating asymmetry and selection against asymmetry. Evolution 48: 658-670. Moller, A. P. 1997. Developmental stability and fitness: a review. Am. Nat. 149: 916-932.

Elternschaftsnachweise bei drei Bruten des Trauerschnäppers (Ficedula hypoleuca) mit jeweils neun Nestlingen

In Pied flycatchers (Ficedula hypoleuca) unusually large clutches containing nine eggs were found regularly. Two alternative hypotheses may explain this phenomenon: Either a single female has produced such an unusually large clutch alone or two females paired with a monoterritorial bigyneous male have laid in sum nine eggs. Here we report about our results obtained by DNA fingerprint analyses of three Pied flycatcher broods containing nine nestlings. For two broods it is evidenced that a single female was the genetic mother of all nine nestlings. In the third instance one nestling was not related to either adult that cared for the young. It is argued that this single case is probably not due to intraspecific brood parasitism. Beim Trauerschnäpper (Ficedula hypoleuca) wird normalerweise angenommen, daß auch ungewöhnlich große Gelege mit 9 Eiern auf nur ein Weibchen zurückgehen. Wir untersuchten drei Bruten mit jeweils 9 Nestlingen mit Hilfe des DNA-Fingerprinting. Dabei ergab sich, daß in 2 Bruten das fütternde ♀ auch die genetische Mutter aller 9 Nestlinge war. In der dritten Brut war 1 Nestling mit keinem der beiden fütternden Altvögel verwandt. Es wird erörtert, warum es sich in diesem Fall vermutlich nicht um innerartlichen Brutparasitismus handelt.

Vaterschaftsnachweise bei einem trigyn verpaarten Trauerschnäpper(Ficedula hypoleuca)

In unserem Untersuchungsgebiet bei Lingen, NW Niedersachsen hatte 1995 fast jedges dritte Trauerschnäpper-♀ ein polygames ♂ zum Partner, wobei der polygame Verpaarungsstatus des ♂ daran erkannt wurde, daß es in zwei — und in einem Fall sogar in drei — Bruthöhlen Junge fütterte (Bigynie bzw. Trigynie). Mit Hilfe molekularbiologischer Methoden (DNA-Fingerprinting) wurde erstmals für einen Trigamisten die Vaterschaft analysiert. Dabei ergab sich, daß es sich bei dem fütternden ♂ in allen Bruten auch um den genetischen Vater jeweils sämtlicher Nestlinge handelte. In our study area near Lingen (52.27 N, 7.15 E), NW Germany polygyny among the Pied Flycatcher came to light through participation of males in feeding at 2 or 3 nestboxes (bigyny or trigyny). In the present paper we report a first time proof of paternity via DNA fingerprinting with the offspring of a trigynist. It could be evidenced that one male was the genetic father of all nestlings in all three broods.