| 1. |
- Arlt, D, et al.
(författare)
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Breeding synchrony does not affect extra-pair paternity in great reed warblers
- 2004
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Ingår i: Behaviour. - : Brill. - 1568-539X .- 0005-7959. ; 141:7, s. 863-880
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Tidskriftsartikel (refereegranskat)abstract
- Breeding synchrony is hypothesised to influence the occurrence and frequency of extra-pair fertilisations (EPFs) in birds irrespective of the social mating system. The two proposed hypotheses make opposite predictions. (1) Synchronous breeding leads to a lower frequency of EPFs because males face a trade-off between mate guarding and obtaining additional matings via extra-pair copulations (EPCs) ('guarding constraint' hypothesis). (2) Synchronous breeding promotes EPFs because females are able to compare displaying males simultaneously, which provides them with more reliable cues for extra-pair mate choice ('mate assessment' hypothesis). In a study of great reed warblers (Acrocephalus arundillaceus) from 1987-1998, annual breeding was asynchronous and the frequency of EPFs was rather low (extra-pair young occurring in 6.4% of the broods). Within this population, however, there was no relationship between the frequency of EPFs and breeding synchrony, thus not favouring any of the two hypotheses. Contrary to assumptions of the hypotheses, mate guarding did not seem to constrain males from engaging in EPCs (disfavouring the 'guarding constraint' hypothesis), and females seem to have repeated opportunities to compare males irrespective of breeding synchrony (disfavouring the 'mate assessment' hypothesis). Our results suggest that breeding synchrony is not an important factor influencing patterns of EPFs in great reed warblers. The low frequency of EPFs may instead be explained by the socially polygynous mating system, where females are less constrained in their choice of a social male.
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| 2. |
- Barber, I., et al.
(författare)
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Behavioural responses to simulated avian predation in female three spined sticklebacks the effect of experimental Schistocephalus solidus infections
- 2004
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Ingår i: Behaviour. - 0005-7959 .- 1568-539X. ; 141, s. 1425-1440
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Tidskriftsartikel (refereegranskat)abstract
- Plerocercoid larvae of Schistocephalus solidus are common parasites of three-spined sticklebacks that require the ingestion of stickleback hosts by birds to complete their life cycle. Amongst wild-caught sticklebacks, infection is associated with a reduction in antipredator behaviour; however, to date no study has examined the escape responses of experimentally infected sticklebacks, and thus assigning causality remains difficult. Here, we compare aspects of the antipredator behaviour of five experimentally infected female sticklebacks with shamexposed controls over a 16 post-exposure week period. During weeks 1-7 post-exposure, the escape responses of infected fish did not differ significantly from those of sham-exposed fish. However, over weeks 9-15, when infected fish had developed plerocercoids of >50 mg—the size at which they become infective to birds —a lower proportion of infected fish performed directional responses and reached cover within 2 s of the strike. Infected fish also performed a lower frequency of ‘staggered dashes’, and a higher frequency of ‘slow swims’, than shamexposed fish over weeks 9-15. Amongst sham-exposed fish, re-emergence from cover was uncommon throughout the study, but infected fish regularly left cover during weeks 9-15. Our results support those of previous studies examining behavioural change in naturally infected fish and, although other explanations remain possible, our finding that behaviour change in experimentally-infected fish is limited to hosts harbouring single infective parasites provides further evidence that the behaviour changes may be parasite adaptations.
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| 3. |
- Berglund, Anders
(författare)
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Many mates make male pipefish choosy
- 1995
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Ingår i: Behaviour. - 0005-7959 .- 1568-539X. ; 132:3-4, s. 213-218
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Tidskriftsartikel (refereegranskat)abstract
- In the sex-role reversed pipefish Syngnathus typhle males search for mates, and prefer to mate with large rather than small females. When mate density was experimentally manipulated, males exerted a mate choice only under high mate density, whereas no mate choice could be demonstrated under low mate density. Hence, when males are infrequently encountered, males reduce the costs associated with an extended mate search by accepting females that otherwise would have been rejected.
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| 4. |
- Bernasconi, G, et al.
(författare)
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Do spermathecal morphology and inter-mating interval influence paternity in the polyandrous beetle Tribolium castaneum?
- 2006
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Ingår i: Behaviour. - : Brill. - 1568-539X .- 0005-7959. ; 143:5, s. 643-658
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In polyandrous insects, postcopulatory sexual selection is a pervasive evolutionary force favouring male and female traits that allow control of offspring paternity. Males may influence paternity through adaptations for sperm competition, and females through adaptations facilitating cryptic female choice. Yet, the mechanisms are often complex, involving behaviour, physiology or morphology, and they are difficult to identify. In red flour beetles (Tribolium castaneum), paternity varies widely, and evidence Suggests that both male and female traits influence the outcome of sperm competition. To test the role of spermathecal morphology and of sperm storage processes on the outcome of sperm competition, we mated each of 26 virgin females with two males. one of which carrying a phenotypic marker to assign offspring paternity. We manipulated the interval between mating with the first and the second male, to create different conditions of sperm storage (overlapping and non-overlapping) in the female reproductive tract. To investigate the role of sperm storage more closely. we examined the relationship between paternity and spermathecal morphology in a subset of 14 experimental females. In addition, we also characterized variation in spermathecal morphology in three different strains, wildtype, Chicago black and Reindeer. No significant influence of the intermating interval was found on the paternity of the focal male, although the direction of the difference was in the expected direction of higher last male paternity for longer intervals. Moreover, paternity was not significantly associated with spermathecal morphology, although spermathecal volume, complexity, and tubule width varied significantly and substantially among individuals in all investigated strains.
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| 5. |
- Bernet, Patricia, et al.
(författare)
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Female-female competition affects female ornamentation in the sex-role reversed pipefish Syngnathus typhle
- 1998
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Ingår i: Behaviour. - 0005-7959 .- 1568-539X. ; 135:5, s. 535-550
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Tidskriftsartikel (refereegranskat)abstract
- 1. In the sex role reversed pipefish Syngnathus typhle females compete for males, and males are more choosy than females. Before mating. females display a temporary sexual ornament in the form of a lateral zigzag pattern. which is an amplification of their permanent colour pattern. 2. In experiments males showed no significant preferences for permanently contrast-rich females, nor for females matching closely with the background. 3. Females in physical contact with a male could potentially develop the ornament, but under female-female competition females were more likely to display it than otherwise. 4. The ornament accurately predicted female mating success. More ornamented females displayed more actively towards males and were found closer to males than were non-ornamented females.
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| 6. |
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| 7. |
- Blomqvist, Donald, 1954, et al.
(författare)
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High frequency of extra-pair fertilisations in the moustached warbler, a songbird with a variable breeding system
- 2005
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Ingår i: Behaviour. - : Brill. - 0005-7959 .- 1568-539X. ; 142:8, s. 1133-1148
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Tidskriftsartikel (refereegranskat)abstract
- We examined the genetic mating system of the moustached warbler Acrocephalus melanopogon, a multi-brooded songbird that sometimes breeds in trios (one female and two males). The second male, which appears relatively late in the breeding cycle, participates in all forms of parental care but provides less care than the pair male. DNA fingerprinting revealed a high frequency of extra-pair paternity: 39% (7/18) of the broods contained extra-pair young, comprising 27% (12/44) of the chicks. An additional 7 broods contained at least 9 chicks (out of 20) that were not sired by the resident male. We were able to assign paternity for 11 (52%) of the extra-pair young. Of these, 7 (64%) were sired by secondary males and 4 (36%) by close neighbours (nesting within 50 m). Consistently, pairs with extra-pair young had more close neighbours, and they also tended to have a secondary male at the nest. Caring for nestlings that they might have sired through extra-pair copulations may be a way for secondary males to salvage their reproductive effort. They may also provide parental care because of the possibility of pairing with the female in future breeding attempts. Our results suggest that female moustached warblers obtain direct benefits (i.e., help with brood care) from extra-pair copulations. However, a skewed fertilisation pattern implies that genetic compatibility between mates and copulation partners may also influence female extra-pair behaviour in this species.
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| 8. |
- Borg, Åsa A., et al.
(författare)
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Presence of same sex individuals negatively affects egg maturation in female guppies (Poecilia reticulata)
- 2006
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Ingår i: Behaviour. - : Brill. - 0005-7959 .- 1568-539X. ; 143, s. 747-761
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Tidskriftsartikel (refereegranskat)abstract
- Competition with individuals of the same sex may affect reproduction, and the effect may depend on own competitive ability. We exposed individual guppy (Poecilia reticulata) females either to larger females, smaller females or held them alone for five weeks. All replicates had visual access to a sexually mature mate. At the end of the experiment, there were no significant differences in daily growth or mass between the three treatments. However, females held alone had a higher reproductive output (in terms of ovary weight and GSI) than females held with either larger or smaller companions. This was mainly caused by a higher number of fully developed eggs in the ovaries of these females. The total number of eggs (including all stages) did not differ between the treatments. We suggest that the 'extra' energy not used in reproduction in the competitive treatments might have been spent on interactions between the females. In guppies socialising with other females seems to impose a cost on female reproduction.
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| 9. |
- Cunha, Mário, et al.
(författare)
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Reduced cannibalism during male pregnancy
- 2016
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Ingår i: Behaviour. - : Brill Academic Publishers. - 0005-7959 .- 1568-539X. ; 153:1, s. 91-106
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Tidskriftsartikel (refereegranskat)abstract
- Cannibalism provides energetic benefits but is also potentially costly, especially when directed towards kin. Since fitness costs increase with time and energy invested in offspring, cannibalism should be infrequent when parental investment is high. Thus, filial cannibalism in male syngnathids, a group known for the occurrence of male pregnancy, should be rare. Using the pipefish (Syngnathus abaster) we aimed to investigate whether cannibalism does occur in both sexes and how it is affected by reproductive and nutritional states. Although rare, we witnessed cannibalism both in the wild and in the laboratory. Unlike non-pregnant males and females, pregnant and postpartum males largely refrained from cannibalising juveniles. Reproducing males decreased their feeding activity, thus rendering cannibalism, towards kin or non-kin, less likely to occur. However, if not continuously fed, all pipefish adopted a cannibal strategy, revealing that sex and life history stages influenced the ratio between the benefits and costs of cannibalism.
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| 10. |
- Dessborn, Lisa, 1976-, et al.
(författare)
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Innate responses of mallard ducklings towards aerial, aquatic and terrestrial predators
- 2012
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Ingår i: Behaviour. - Leiden, Netherlands : Brill Academic Publishers. - 0005-7959 .- 1568-539X. ; 149:13-14, s. 1299-1317
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Tidskriftsartikel (refereegranskat)abstract
- Reproductive success in ducks is strongly influenced by predation on the breeding grounds. Ducklings are targeted by a range of terrestrial, aerial and aquatic predators, giving a strong selective advantage to individuals and broods that have effective ways to avoid predation. In experiments on naive mallard (Anas platyrhynchos) ducklings without an accompanying adult female we investigated the innate ability to identify and avoid threats at varying intensity from aerial, aquatic and terrestrial predators. Ducklings displayed increased vigilance in response to pre-recorded calls of predatory birds, representing a low level of threat. They did not react to visual and olfactory stimuli generated by motionless northern pike (Esox lucius). Neither did they show a strong response to caged American mink (Neovison vison) (visual and olfactory stimuli), although they avoided the area with the mink, indicating a certain level of recognition. High intensity threats were simulated by staging attacks from aerial (goshawk, Accipiter gentilis) and aquatic predators (northern pike). The aerial attack made ducklings dive and scatter under water, whereas the response to attack by pike was to run on the water and scatter in different directions. The lack of response to a ‘passive’ pike and the rather weak avoidance of mink indicate that olfactory cues are not as important in identifying a potential predatory threat by ducklings as are auditory cues. Visual cues appear to be of little importance unless they are combined with movement, and a clear response is only triggered when the intensity of predator threat is high. Mallard ducklings, thus, show an innate capacity to adjust anti-predator behaviour to different predator types and to threat intensity. Our study highlights the general trade-off between foraging needs and predator avoidance, but also second-order trade-offs in which innate avoidance behaviour towards one type of predator may increase predation risk from another.
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