We experimentally reduced clutch size of Great Tits Parus major to investigate the effects on parental care (including Daily Energy Expenditure, DEE, measured with doubly labelled water), and the relationship between DEE and the residual reproductive value. The length of a working day was not affected, but the nestling phase was 0.7 days (4%) shorter in experimental clutches. Males fed reduced ...

Thuman, KA. 2003. Female reproductive strategies in the ruff (Philomachus pugnax). Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 830. 24 pp. Uppsala. ISBN 91-554-5599-9 Traditionally, females have been considered to be strictly monogamous. Today, we know that females in the majority of species actively seek out and ma...

1985). Female body size is positively correlated both Mate choice by males in organisms that do not make obviously costly contributions to offspring should be expected where sperm production is limited and courtship time is finite. Although male guppies (Poecilia reticulata) contribute only sperm to their offspring, preliminary evidence points to male mate choice in this species. Thus, the hypo...

In fig wasps, mating takes place among the offspring of one or a few foundress mothers inside the fig from which mated females disperse to found new broods. Under these conditions, related males will compete with each other for mating and several studies have shown female bias in brood sex ratios as a response to Local Mate Competition (LMC). Studying Pegoscapus tonduzi which pollinates Ficus c...

BACKGROUND Organisms face trade-offs regarding their life-history strategies, such as decisions of single or multiple broods within a year. In passerines displaying facultative multiple breeding, the probability of laying a second clutch is influenced by several life-history factors. However, information about the mechanistic background of these trade-offs is largely lacking. Leptin is a protei...

Parental care of unrelated offspring is widespread but not well understood. We used 11 polymorphic microsatellite loci to investigate the relatedness of fry and parentally caring adults in a 118-nest colony of the socially and genetically monogamous cichlid fish Neolamprologus caudopunctatus in Lake Tanganyika. There was a high proportion of brood mixing, with 59% of 32 broods containing fry un...

We used microsatellite DNA markers to genotype chicks in 10 broods of lek-breeding sage grouse, Centrocercus urophasianus, whose mothers' behaviour was studied by radio-tracking and observing leks. Previous behavioural studies suggested that almost all matings are performed by territorial males on leks and that multiple mating is rare. Two broods (20%) were sired by more than one male. Genetic ...

We explored behavioural adjustments made by parent house sparrows, Passer domesticus, when the nutritional condition of their dependent nestlings was improved experimentally. Male parents responded to artificially supplemented broods by increasing food deliveries, whereas female parents continued matching the already high rate of control females. Thus, parental care was not truncated in the fac...

animals that breed in ground holes can be exposed to higher doses of radiation from natural radioactive isotopes, including radon and its daughters, present in soil air. one of such species is the sand martin riparia riparia. examination of natural burrows in sand mines revealed radon levels of 2.82-1320 bq/m3 in the examined soil horizon where martins dug their burrows. it was shown that adult...