title: Influence of mate preference and laying order on maternal allocation in a monogamous parrot species with extreme hatching asynchrony.
abstract: It is well established that in many avian species, prenatal maternal resource allocation varies both between and within clutches and may affect offspring fitness. Differential allocation of maternal resources, in terms of egg weight and yolk composition, may therefore allow the female to adjust brood reduction and to fine-tune reproductive investment in accordance with the expected fitness returns. The adaptive value of such maternal resource allocation is thought to be context-dependent as well as species-specific. We investigated the effects of female preference for her mate on the allocation of prenatal maternal resources in the budgerigar, Melopsittacus undulatus, a monogamous species of parrot that shows an extreme hatching asynchrony. We assessed mate preferences in a two-way preference test and allowed females two breeding rounds: one with the preferred and one with the non-preferred partner. We found no effect of preference on either latency to lay or clutch size, but females mated with the preferred partner laid eggs that contained significantly more yolk. Their eggs also contained significantly more androstenedione but not testosterone. Our results suggest that in this species, female preference may influence maternal resource allocation, and that the functional roles of each androgen in the yolk should be considered separately. In addition, we found a significant effect of laying order on egg and yolk weight as well as on yolk testosterone and androstenedione levels. These measures, however, did not change linearly with the laying order and render it unlikely that female budgerigars compensate for the extreme hatching asynchrony by adjusting within-clutch allocation of prenatal maternal resources.
authors: Department of Biology, Research Group Ethology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium. Electronic address: Stefanie.lahaye@uantwerpen.be.
authors: Stefanie E P
authors: SE
authors: Lahaye
authors: Department of Biology, Research Group Ethology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium.
authors: Marcel
authors: M
authors: Eens
authors: Department of Biology, Research Group Ethology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium.
authors: Arne
authors: A
authors: Iserbyt
authors: Department of Behavioural Biology, Centre for Behaviour and Neurosciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors: Ton G G
authors: TG
authors: Groothuis
authors: Department of Behavioural Biology, Centre for Behaviour and Neurosciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors: Bonnie
authors: B
authors: de Vries
authors: Department of Biology, Research Group Ethology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium.
authors: Wendt
authors: W
authors: Müller
authors: Department of Biology, Research Group Ethology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium; Institute for Education and Information Sciences, Research Unit Didactica, University of Antwerp, Antwerp, Belgium.
authors: Rianne
authors: R
authors: Pinxten
mesh_terms: D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D052284:Clutch Size; D004530:Egg Yolk / Q000378:metabolism / Q000502:physiology; D005260:Female; D008297:Male; D008425:Maternal Behavior / Q000502:physiology*; D052586:Mating Preference, Animal / Q000502:physiology*; D046408:Melopsittacus / Q000502:physiology*; D010063:Ovum / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology; D013739:Testosterone / Q000378:metabolism
chemical_list: D013739:Testosterone; D000735:Androstenedione
keywords: Androstenedione; Differential allocation; Hatching asynchrony; Male attractiveness; Maternal effects; Melopsittacus undulatus; Reproductive investment; Testosterone; Yolk hormones