| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- Horowitz, Laura, et al.
(författare)
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Post-conflict non-affiliative behavioural strategies and subsequent social interaction in preschool boys with language impairment in comparison to preschool boys with typical language skills
- 2008
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Ingår i: Behaviour. - : Brill. - 0005-7959 .- 1568-539X. ; 145:11, s. 1671-1700
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Tidskriftsartikel (refereegranskat)abstract
- Conflicts between 20 boys (4-6 years old) with typical language development (TL) and between 11 boys (4-7 years old) with Language Impairment (LI) were examined in naturalistic preschool settings. Post-conflict aggression, passive withdrawal (auto-manipulation/irrelevant vocalizations) and active withdrawal (leaving conflict scene) were examined in relation to preceding behavioural situations and the likelihood of social interaction after conflict management. The boys with TL tended to display aggression to a greater extent than the boys with LI in conflicts with pre-conflict social interaction and in the role of conflict victim. However it was revealed that the boys with TL displayed passive withdrawal significantly more often in conflicts without pre-conflict social interaction than in conflicts with pre-conflict interaction. When in the role of conflict victims the boys with LI conducted active withdrawal significantly more than the boys with TL. Reconciliation (former opponents exchange friendly contact following conflict termination) has been shown to facilitate social interaction after terminated conflict management. However, this link appeared to be weakened significantly when initial post-conflict responses were active withdrawal (more representative LI strategy) than after reconciled conflicts without active withdrawal. Clinical treatment and educational intervention should address emotional regulation and referential communication to facilitate developmental social interaction.
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| 5. |
- Nilsson, Anders, et al.
(författare)
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Friends and foes in foraging: intraspecific interactions act on foraging-cycle stages
- 2006
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Ingår i: Behaviour. - : Brill. - 1568-539X .- 0005-7959. ; 143:6, s. 733-745
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Tidskriftsartikel (refereegranskat)abstract
- Intraspecific interactions may increase or decrease foraging rates of individual consumers, and such facilitation or interference interactions should affect individual foraging economies as well as predator-prey processes at the population level. To mechanistically predict individual foraging performance, we need to investigate the effects of positive and negative interactions on separate foraging-cycle stages. We illustrate the importance and viability of examining the effects of facilitation and interference on different foraging-cycle stages using three piscivore species as a model system. We studied individual foraging behaviour when alone or in the presence of conspecifics, and show that northern pike foraging in the presence of conspecifics decrease attack frequencies and consumption rates, although no explicit agonistic behaviours were recorded. Pikeperch increase consumption rates in conspecific groups, possibly through a prey-mediated increase in capture success, as pikeperch showed no direct behavioural interactions. The actively cooperating Eurasian perch increase capture success and consumption rates in groups. The results demonstrate the need to combine behavioural studies of positive and negative effects of intraspecific interactions on foraging-cycle stages with quantifications of overall consumption rates. Pure behavioural observations may result in misinterpretations of the effects of interactions on foraging, while studies on consumption rates only would lack the mechanistic base of the obtained results. We also suggest that effects of intraspecific interactions during the foraging cycle should be incorporated in mechanistic models of facilitation and interference to elucidate the link between individual behaviours and higher-order processes.
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| 6. |
- Pechacek, Peter, et al.
(författare)
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Monogamy with exceptions: Social and genetic mating system in a bird species with high paternal investment
- 2005
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Ingår i: Behaviour. - : Brill. - 0005-7959 .- 1568-539X. ; 142:8, s. 1093-1114
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Tidskriftsartikel (refereegranskat)abstract
- Animal mating systems are strongly linked to costs and benefits associated with parental care. A high degree of male parental care may explain the occasional occurrence of social polyandry in some monogamous birds such as woodpeckers. We examined mating and parental behaviours of 55 three-toed woodpeckers Picoides tridaclylus, and used DNA fingerprinting to study its genetic mating system over 11 years. Sexes shared nest hole guarding and parental care, but males allocated significantly more time to territory defence, cavity excavation and feeding young than females. Two (7.4%) of the 27 females were polyandrous, each paired simultaneously with two males. Four (7.3%) out of 55 chicks were extra-pair (15.4% of the broods). Two of these chicks were associated with social polyandry, and one with female parasitism. Hence, three-toed woodpeckers were socially and genetically predominantly monogamous. We propose that both social and genetic polyandry in woodpeckers are constrained by the long duration of cavity excavation, few re-mating opportunities, and by the fact that bi-parental care is important for reproductive success.
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| 7. |
- Poschadel, J R, et al.
(författare)
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Response to chemical cues from conspecifics reflects male mating preference for large females and avoidance of large competitors in the European pond turtle, Emys orbicularis
- 2006
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Ingår i: Behaviour. - : Brill. - 0005-7959 .- 1568-539X. ; 143, s. 569-587
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Tidskriftsartikel (refereegranskat)abstract
- We examined chemical communication in male and female European pond turtles (Emys orbicularis). In simultaneous binary choice tests, a focal animal was given a choice between pheromones from a conspecific and a choice chamber containing untreated water. Females did not show a preference, both when male and when female stimuli were presented. On the contrary, males preferred the odor of a female over untreated water, suggesting that males actively search for females. The strength of preference was positively correlated with the body size difference between the female and the focal male, indicating that males prefer to mate with larger females. Female fecundity is positively correlated with female size in E. orbicularis, which may account for male choosiness. No overall preference for the stimulus animal was observed when males were presented cues from another male. However, the strength of preference was negatively correlated with the difference in body size. Males avoided large males, but oriented towards smaller stimulus males. This reflects that males form dominance hierarchies, where large males aggressively attack smaller ones. Far-range chemical communication probably enables males to minimize the risk of costly aggressive interactions. This is, to our knowledge, the first study on the role of chemical cues for inter-and intrasexual communication in the European pond turtle.
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| 8. |
- Westlund, Karolina, et al.
(författare)
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Age effects and gender differences on post-conflict reconciliation in preschool children
- 2008
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Ingår i: Behaviour. - : Brill. - 0005-7959 .- 1568-539X. ; 145, s. 1525-1556
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Tidskriftsartikel (refereegranskat)abstract
- We studied conflict management and post-conflict affiliative interactions (reconciliation) in 3-to-6 year-old preschool children. We found development in reconciliatory proficiency with age for boys, but girls reconciled at similar levels throughout the age span. After peer conflict, 3-year-old boys were less likely to reconcile than same-aged girls, or as boys aged 4-6 years. Gender differences were not manifested in older same-age-groups (4-6-year olds). Younger boys (3-4-year olds) experienced higher reconciliation rates in conflicts with older boys (5-6-year olds) than in conflicts with same aged boys. We found no significant age or gender effects in distribution of reconciliatory repertoire or frequency of non-affiliative conflict management strategies (aggression and displacement activities, indicative of stress responses). However, 6-year-old children were more likely than younger children to mediate in conflicts in which they were not opponents, but had witnessed. Though not confirmed statistically, this phenomenon appeared more pronounced in girls than boys. Together, our results suggest that at 3 years of age, preschool children employ sophisticated behaviours to resolve conflicts, displaying remarkable receptiveness and responsiveness to reconciliatory behaviours exhibited by older opponents.
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| 9. |
- Skog, Malin
(författare)
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Intersexual differences in European lobster (Homarus gammarus): recognition mechanisms and agonistic behaviours
- 2009
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Ingår i: Behaviour. - 1568-539X. ; 146, s. 1071-1091
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Tidskriftsartikel (refereegranskat)abstract
- Dominance can be maintained through status recognition or recognition of individual (familiar) opponents. In crustaceans, both types of recognition exist, often based on chemical signals. Fight behaviours involved in establishment and maintenance of dominance relationships in male and female European lobster (Homarus gammarus) were examined. Same-sex pairs of size-matched animals interacted on two consecutive days, encountering either the same (familiar) or another (unfamiliar) opponent of the opposite dominance status in the second fight. Results show that both female and male H. gammarus establish dominance in a first encounter, and maintain dominance in a second interaction against a familiar animal, resulting in decreased fight duration and lower aggression levels. Female losers that met an unfamiliar dominant also had short second days with low aggression, while male losers responded to unfamiliar animals with high aggression and long fights. Thus, males distinguish between familiar and unfamiliar opponents, indicating individual recognition whereas females do not, indicating that they use dominance status recognition rather than individual recognition. Female-female fights involved more high-level aggression (claw lock) than male-male fights, contrary to the belief that male lobsters are more aggressive than females. H. gammarus fights also escalated to unrestrained violence fast, indicating low levels of ritualisation.
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| 10. |
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