1,721,079 research outputs found
Leaders Are More Attractive: Birds with Bigger Yellow Breast Patches Are Followed by More Group-Mates in Foraging Groups
Full text linkSocial network theory provides a perfect tool to better understand the population-level consequences of how individuals interact and make their decisions; however, this approach is generally overlooked among evolutionary biologists interested in social relationships. Here, we used social network analysis to examine the patterns of leader-follower interactions in relation to individual characteristics in foraging groups of free-living rock sparrows (Petronia petronia). We found that yellow feather ornamentation, a carotenoid-based trait, was the best predictor of leadership: birds with bigger ornaments exerted greater influence in the foraging groups and were followed by more group-mates than less elaborate individuals. An individual's tendency for eliciting followings was not influenced by sex, condition or the level of parental investment. None of the above individual characteristics had significant effect on the tendency of individuals to follow others. Our results indicate that a sexually selected trait can also play a significant role in group coordination and social organization of a species
Bearded Reedlings Adjust Their Pair-Bond Behaviour in Relation to the Sex and Attractiveness of Unpaired Conspecifics
Full text linkAn individual's investment in mating or keeping a pair bond intact may be influenced not only by the attractiveness of its current mate, but also by that of other potential mates. In this study, we investigated the effect of relative attractiveness on pair-bond behaviour in bearded reedlings, Panurus biarmicus. We showed that mate attractiveness, in terms of beard length in males and tail length in females, influenced courtship behaviour when the pair was kept isolated. In the presence of a conspecific, contact initiations within a pair increased. This increment was mainly related to the sex of the unpaired conspecific, however, and less to differences in attractiveness between the current partner and the unpaired conspecific. Female contact initiations towards potential extra mates were independent of male attractiveness, whereas male contact behaviour was significantly influenced by female attractiveness. However, females displayed more contact initiations to their current mate when they were less attractive than the unpaired females. Males decreased their overtures towards other females with increasing attractiveness of their current mates. Overall, our results suggested that, when there was a risk of losing their mate, bearded reedlings adjust their pair-bond investment mainly in response to the presence or absence of a competitor, and fine-tune investment to a lesser extent in response to the attractiveness of that potential competitor
Only females in poor condition display a clear preference and prefer males with an average badge
Full text linkAbstract Background Female condition-dependent variation in mate preference may have important evolutionary implications, not only within the same population but also among populations. There are few experiments, however, on how condition and/or genotype influences female mate preferences. The black throat patch of the male house sparrow, Passer domesticus, is an intensively studied plumage trait. It is often referred to as a 'badge of status' and seems to be involved in female mate choice, but differences exist among populations. Between-population variation in mate preference may occur for condition-dependent mate preferences. We tested the hypothesis that female preference may vary with female quality (body condition). Therefore, we measured female preference for badge size using an aviary two-choice test in which females were presented with two males that had different sizes of badges (enlarged or averaged). Results Overall we did not find a female preference for enlarged or average badges, but low-quality females spent more time near average badge males. Conversely, high-quality females did not show a clear preference. Conclusions Collectively, these results indicate that female preference varies with female quality. Differences in female condition are causes of within-population variation in mating preferences. To our knowledge, our results provide one of the first experimental evidences that variation in preference for a male ornament is associated with female condition. In our study, however, only females of low condition displayed a clear mate preference. Differences observed among populations could be partly explained by differences in female condition.</p
Sexual selection, multiple traits and pair-bond behaviour in bearded reedlings (Panurus biarmicus).
No full textIncorporating evolutionary processes in the identification of spatial conservation priorities for birds. 19th International Conference of the European Bird Census Council, 17-21 September 2013, Cluj, Romania.
No full textIncorporating evolutionary processes in the identification of spatial conservation priorities for birds.
No full text
Sexual conflict over parental care in a species with female and male brood desertion
No full textEach parent has limited resources to invest in current reproduction, so each parent would benefit if its mate did more of the work, which generates a sexual conflict between parents. Parental care behaviour is an adaptive decision, involving trade-offs between remating ( and consequently desertion of the brood) and continuing parental effort. The rock sparrow, Petronia petronia, is an unusual species in which brood desertion can occur in both sexes. Consequently, the rock sparrow is a good species to investigate the behavioural response of parents to the desertion by their mates and whether sexual difference in this response exists. We compared parental effort of pair members divided into three groups: pairs that cooperated, females that deserted the brood and males that deserted. During the period of biparental care, females fed offspring more often than males, but there were no differences among the three groups. Following desertion the total amount of care in biparental, female-only and male-only broods differed, because both sexes adjusted their care to the absence of their mates, but females overcompensated the mate's absence while males only partially compensated. Nestling survival rate was positively correlated with feeding rate and the mean survival rate was lower in the male-only broods. We suggest that both parents, in a negotiation process, would benefit from withholding parental investment, as proposed in recent theoretical models on sexual conflict over parental care. Altogether our results show an unexpected plastic response of parents to care during the desertion process
An experiment on the function of the long-term pair bond period in the socially monogamous bearded reedling
No full textPair bond duration and age are suggested to be important determinants for reproductive success in long-term monogamous pair bonding. These two effects are generally difficult to separate, however, and experimental approaches are scarce. We experimentally examined the role of the extended pair bond period, controlling for age and experience, in the bearded reedling, Panurus biarmicus. In this species pairs form in juvenile flocks and usually remain stable for life. We experimentally manipulated the pair-formation period in aviary pairs prior to their first breeding season and observed the effect of varying pair bond duration on breeding success, male parental effort and breeding coordination. This was done for pairs with long (6.5. months), medium (4. months) and short (2. weeks) formation periods. Our results suggest that the length of the bonding period does not influence male parental effort, as males with medium and short formation periods did not reduce their parental effort in nest building, during incubation or in nestling provisioning. Nevertheless, coordination of pair partners (in terms of simultaneous start of nest building) occurred more often when the pair bond period was long, and these pairs also started breeding earlier. Pairs with long bonds succeeded more often in breeding attempts and had higher hatching and fledging success than pairs with medium and short formation periods. Thus, our results support the hypothesis that the duration of the pair bond may improve coordination within a pair before the start of breeding and thereby may result in enhanced reproductive success
Is female mate preference based on the interaction between static and dynamic signals in bearded reedlings?
No full textIn many animal species ornaments and display behaviours are used together in intersexual communication. Few studies, however, have simultaneously explored how the static and dynamic components interact. We examined the significance of behaviour (e.g. dominance status) in comparison with beard length for the mate choice process in a bird species, the bearded reedling, Panurus biarmicus. In choice experiments, females were confronted with two males of varying beard length (artificially shortened or elongated) and status (dominant/subdominant). The results suggest that female choice is primarily based on beard length whereas dominance seems to be less important. Our results indicate that the beard length plays an important role in female choice in this species, as previously reported. Nevertheless, dominance status has a slight complementary effect. Beard length and behaviour seem to inform the female about the same aspect of male condition but with a different error probability. However, additional studies in which display rates and song properties are directly manipulated are needed
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