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Jan Komdeur - One of the best experts on this subject based on the ideXlab platform.
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explicit experimental evidence for the effectiveness of proximity as mate guarding behaviour in reducing extra pair fertilization in the seychelles warbler
Molecular Ecology, 2007Co-Authors: Jan Komdeur, Terry Burke, David S RichardsonAbstract:Extra-pair copulations (EPCs; copulations outside the pair bond) are widespread in birds and may result in extra-pair fertilizations (EPFs). To increase reproductive success, males should not only seek to gain EPFs, but also prevent their own females from gaining EPFs. Although males could reduce the number of EPCs by their mates, this does not necessarily mean that they reduce the number of EPFs; indeed several studies have found no association between EPCs and EPFs. Male Seychelles warblers (Acrocephalus sechellensis) follow their partner closely during the Period when the pair female is most receptive (Fertile Period). We show that males that guarded their mates more closely were less likely to have extra-pair young in their nest. This study on the Seychelles warbler is the first to provide explicit experimental evidence that mate guarding is effective in reducing EPFs. First, in territories where free-living males were induced to stop mate guarding during the pair female's Fertile Period, extra-pair parentage was higher than in the control group. Second, in the experimental group, the probability of having an extra-pair nestling in the nest was positively associated with the number of days during the Fertile Period for which mate guarding was artificially stopped. Thus, male mate guarding was effective in reducing the risk of cuckoldry.
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is uv signalling involved in male male territorial conflict in the blue tit cyanistes caeruleus a new experimental approach
Behaviour, 2007Co-Authors: Peter Korsten, Thomas H Dijkstra, Jan KomdeurAbstract:Structurally-based ultraviolet (UV) coloration of plumage can signal male quality and plays a role in female mate choice in many bird species. UV-reflecting badges could also be important signals in male-male competition. We tested if territorial blue tit (Cyanistes caeruleus) males discriminate between conspecific male intruders which differ in the UV reflectance of their crown feathers. To this aim, we used a new experimental approach in which we simultaneously (instead of sequentially) introduced two male blue tit taxidermic mounts in the territories of resident males during the female Fertile Period; one mount with natural crown UV reflectance and one mount with reduced crown UV. The two mounts provoked strong aggressive reactions from resident males. Males specifically directed their aggression to conspecific intruders, as a male blue tit mount received substantially more aggression than a mount of a European robin (Erithacus rubecula). However, aggression of resident males did not vary between the UV-reduced and the control mount. Furthermore, the variation in natural crown UV reflectance of the resident males did not predict the intensity of their aggressive response. Contrary to previous findings our results suggest that UV signals play only a limited role in male-male interactions during territorial intrusions in the female Fertile Period.
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weather conditions affect levels of extra pair paternity in the reed bunting emberiza schoeniclus
Journal of Avian Biology, 2006Co-Authors: Karen M Bouwman, Jan KomdeurAbstract:Extra-pair paternity (EPP) is common in many socially monogamous birds, but large variations in frequency of EPP are found both between and within species. Local ecological factors can affect the costs and benefits of extra-pair mating behaviour, and may therefore influence the chance that individuals engage in extra-pair copulations (EPCs). We investigated the effect of weather conditions during the peak Fertile Period of the female on the levels of EPP in reed buntings Emberiza schoeniclus. The reed bunting is a socially monogamous passerine, with extremely high levels of EPP (50% of offspring in 80% of broods). We found that higher daily minimum temperatures and more rainfall during the peak Fertile Period were associated with lower proportions of EPP. As during adverse weather conditions individuals have to invest more in self maintenance, we suggest that during long Periods of rain the extra-pair mating behaviour of all individuals will be restricted, leading to lower proportions of EPP. During cold mornings, time-consuming activities such as mate guarding are likely to be more strongly affected than less time-consuming activities such as EPCs, leading to higher proportions of EPP.
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explicit experimental evidence for the role of mate guarding in minimizing loss of paternity in the seychelles warbler
Proceedings of The Royal Society B: Biological Sciences, 1999Co-Authors: Jan Komdeur, Femmie J L Kraaijeveldsmit, Ken Kraaijeveld, Pim EdelaarAbstract:Extra-pair copulations (EPCs) (copulations outside the pair bond) resulting in extra-pair fertilizations (EPFs) are widespread in birds. To increase reproductive success, males should not only seek EPCs, but also prevent their females from having EPFs. Male Seychelles warblers (Acrocephalus sechellensis) follow their partner closely during the Period when these females are most receptive (Fertile Period). The Seychelles warbler is the first species to offer explicit experimental evidence that mate guarding functions as paternity guarding: in territories where free-living males were induced to stop mate guarding during the pair female's Fertile Period, the rates of intrusions by other males and successful EPCs (male mounting female) were significantly higher than those observed in the control group and in the absence of mate guarding the frequency of successful EPCs increased significantly with local male density. Male warblers do not assure their paternity through frequent copulations to devalue any sperm from other males: males do not copulate with their partners immediately following a successful EPC obtained by their partners, the frequency of successful within-pair copulations does not increase with the frequency of successful EPCs and females initiate all successful copulations and are capable of resisting copulation attempts.
Bart Kempenaers - One of the best experts on this subject based on the ideXlab platform.
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exposure to predator models during the Fertile Period leads to higher levels of extra pair paternity in blue tits
Journal of Animal Ecology, 2020Co-Authors: Peter Santema, Mihai Valcu, Bart KempenaersAbstract:: The perceived risk of predation can affect breeding behaviour and reduce reproductive success in prey species. Individuals exposed to predators may also adopt different mating tactics with potential consequences for the distribution of paternity in socially monogamous species that engage in extra-pair copulations. We experimentally increased perceived predation risk during the Fertile Period in blue tits Cyanistes caeruleus. Every morning between nest completion and the onset of egg laying, we presented a model of either a predator or a non-predator (control) near active nestboxes. Broods from pairs exposed to predators had higher levels of extra-pair paternity than control broods. This mainly resulted from a higher proportion of extra-pair offspring in broods with at least one extra-pair young. Females exposed to predators first emerged from the nestbox later in the morning, stayed away from the nestbox for longer and were less likely to be visited at the nest by their social mate, but we detected no behavioural differences once the model was removed. Our results suggest that the higher rates of extra-pair paternity resulted from the disruption of morning routines, which may have inhibited within-pair copulations or increased opportunities for females to engage in extra-pair copulations. We conclude that the perceived risk of predation can have substantial effects on levels of extra-pair paternity.
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Exposure to predator models during the Fertile Period leads to higher levels of extra-pair paternity in blue tits.
Journal of Animal Ecology, 2019Co-Authors: Peter Santema, Mihai Valcu, Bart KempenaersAbstract:The perceived risk of predation can affect breeding behaviour and reduce reproductive success in prey species. Individuals exposed to predators may also adopt different mating tactics with potential consequences for the distribution of paternity in socially monogamous species that engage in extra-pair copulations. We experimentally increased perceived predation risk during the Fertile Period in blue tits Cyanistes caeruleus. Every morning between nest completion and the onset of egg laying, we presented a model of either a predator or a non-predator (control) near active nestboxes. Broods from pairs exposed to predators had higher levels of extra-pair paternity than control broods. This mainly resulted from a higher proportion of extra-pair offspring in broods with at least one extra-pair young. Females exposed to predators first emerged from the nestbox later in the morning, stayed away from the nestbox for longer and were less likely to be visited at the nest by their social mate, but we detected no behavioural differences once the model was removed. Our results suggest that the higher rates of extra-pair paternity resulted from the disruption of morning routines, which may have inhibited within-pair copulations or increased opportunities for females to engage in extra-pair copulations. We conclude that the perceived risk of predation can have substantial effects on levels of extra-pair paternity.
Peter Santema - One of the best experts on this subject based on the ideXlab platform.
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exposure to predator models during the Fertile Period leads to higher levels of extra pair paternity in blue tits
Journal of Animal Ecology, 2020Co-Authors: Peter Santema, Mihai Valcu, Bart KempenaersAbstract:: The perceived risk of predation can affect breeding behaviour and reduce reproductive success in prey species. Individuals exposed to predators may also adopt different mating tactics with potential consequences for the distribution of paternity in socially monogamous species that engage in extra-pair copulations. We experimentally increased perceived predation risk during the Fertile Period in blue tits Cyanistes caeruleus. Every morning between nest completion and the onset of egg laying, we presented a model of either a predator or a non-predator (control) near active nestboxes. Broods from pairs exposed to predators had higher levels of extra-pair paternity than control broods. This mainly resulted from a higher proportion of extra-pair offspring in broods with at least one extra-pair young. Females exposed to predators first emerged from the nestbox later in the morning, stayed away from the nestbox for longer and were less likely to be visited at the nest by their social mate, but we detected no behavioural differences once the model was removed. Our results suggest that the higher rates of extra-pair paternity resulted from the disruption of morning routines, which may have inhibited within-pair copulations or increased opportunities for females to engage in extra-pair copulations. We conclude that the perceived risk of predation can have substantial effects on levels of extra-pair paternity.
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Exposure to predator models during the Fertile Period leads to higher levels of extra-pair paternity in blue tits.
Journal of Animal Ecology, 2019Co-Authors: Peter Santema, Mihai Valcu, Bart KempenaersAbstract:The perceived risk of predation can affect breeding behaviour and reduce reproductive success in prey species. Individuals exposed to predators may also adopt different mating tactics with potential consequences for the distribution of paternity in socially monogamous species that engage in extra-pair copulations. We experimentally increased perceived predation risk during the Fertile Period in blue tits Cyanistes caeruleus. Every morning between nest completion and the onset of egg laying, we presented a model of either a predator or a non-predator (control) near active nestboxes. Broods from pairs exposed to predators had higher levels of extra-pair paternity than control broods. This mainly resulted from a higher proportion of extra-pair offspring in broods with at least one extra-pair young. Females exposed to predators first emerged from the nestbox later in the morning, stayed away from the nestbox for longer and were less likely to be visited at the nest by their social mate, but we detected no behavioural differences once the model was removed. Our results suggest that the higher rates of extra-pair paternity resulted from the disruption of morning routines, which may have inhibited within-pair copulations or increased opportunities for females to engage in extra-pair copulations. We conclude that the perceived risk of predation can have substantial effects on levels of extra-pair paternity.
Hans Ellegren - One of the best experts on this subject based on the ideXlab platform.
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breeding synchrony and paternity in the barn swallow hirundo rustica
Behavioral Ecology and Sociobiology, 1999Co-Authors: Nicola Saino, Craig R Primmer, Hans EllegrenAbstract:The barn swallow (Hirundo rustica) is a socially monogamous passerine which usually breeds in colonies where extra-pair copulations are frequent. Males intensively guard their mates during the female Fertile Period. Since males are more likely to be available for extra-pair copulations when their mate is not Fertile, synchrony in timing of breeding may affect paternity of individual males. In this study, we analysed the change in mate-guarding rate by males in relation to the fertility condition of the female, and the relationships between breeding synchrony and density with paternity in first broods of 52 male barn swallows. Paternity (proportion of nestlings fathered in own brood) was assessed by typing of three highly polymorphic microsatellite loci. Mate guarding by males peaked during the Fertile Period of their mates. Paternity increased as breeding synchrony in the colony increased. Paternity of barn swallows is positively associated with the degree of exaggeration of male tail ornaments. The relationship between male ornamentation and paternity was partly mediated by an effect of ornament size on breeding synchrony. We suggest that females might delay breeding with low-quality males to enhance their opportunities for being fertilised by high-quality extra-pair males.
Delwyn G Cooke - One of the best experts on this subject based on the ideXlab platform.
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definition of the potentially Fertile Period from urinary steroid excretion rates part ii a threshold value for pregnanediol glucuronide as a marker for the end of the potentially Fertile Period in the human menstrual cycle
Steroids, 1998Co-Authors: Leonard F Blackwell, James B Brown, Delwyn G CookeAbstract:Abstract Application of time series analysis to a database containing serial pregnanediol data from 113 complete ovulatory menstrual cycles contributed by 83 women of proven fertility and 68 cycles for which pregnanediol values were available over the ovulatory Period, detected the first statistically significant rise in pregnanediol excretion for all cycles for which a baseline was available ( n = 170). However, even at the 99% confidence level, for 22% of cycles a rise was observed before the presumed day of ovulation. Therefore, a threshold value for pregnanediol was sought from the database as a better marker for the end of fertility. A value of 1.4 mg per 24 h was not reached before day 2 after the pre-ovulatory estrogen peak day for 96% of the cycles. In the remaining 4% of cycles it was reached one day after the total estrogen peak day. The validity of this threshold was confirmed in extensive studies using the Ovarian Monitor where the equivalent is 6.3 μmol per 24 h of pregnanediol glucuronide and measurements are performed on timed urine specimens with a minimum collection time of three hours. These studies were as follows: 1) a World Health Organization study on the use of the Ovarian Monitor as a fertility self test in the home (108 cycles), 2) a multicenter study on returning fertility during breast feeding conducted by Family Health International (73 women), and 3) the general application of the Ovarian Monitor for pregnancy achievement and avoidance during the past ten years (over 250,000 PdG assays performed in ten countries). With rare exceptions, the use of these threshold values is applicable for all women provided correction is made for urine volume.
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definition of the potentially Fertile Period from urinary steroid excretion rates part ii a threshold value for pregnanediol glucuronide as a marker for the end of the potentially Fertile Period in the human menstrual cycle
Steroids, 1998Co-Authors: Leonard F Blackwell, James B Brown, Delwyn G CookeAbstract:Application of time series analysis to a database containing serial pregnanediol data from 113 complete ovulatory menstrual cycles contributed by 83 women of proven fertility and 68 cycles for which pregnanediol values were available over the ovulatory Period, detected the first statistically significant risk in pregnanediol excretion for all cycles for which a baseline was available (n = 170). However, even at the 99% confidence level, for 22% of cycles a rise was observed before the presumed day of ovulation. Therefore, a threshold value for pregnanediol was sought from the database as a better marker for the end of fertility. A value of 1.4 mg per 24 h was not reached before day 2 after the pre-ovulatory estrogen peak day for 96% of the cycles. In the remaining 4% of cycles it was reached one day after the total estrogen peak day. The validity of this threshold was confirmed in extensive studies using the Ovarian Monitor where the equivalent is 6.3 mumol per 24 h of pregnanediol glucuronide and measurements are performed on timed urine specimens with a minimum collection time of three hours. These studies were as follows: 1) a World Health Organization study on the use of the Ovarian Monitor as a fertility self test in the home (108 cycles), 2) a multicenter study on returning fertility during breast feeding conducted by Family Health International (73 women), and 3) the general application of the Ovarian Monitor for pregnancy achievement and avoidance during the past ten years (over 250,000 PdG assays performed in ten countries). With rare exceptions, the use of these threshold values is applicable for all women provided correction is made for urine volume.