| 1. |
- Dey, Cody J., et al.
(författare)
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Direct benefits and evolutionary transitions to complex societies
- 2017
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Ingår i: Nature Ecology and Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 1:5
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Tidskriftsartikel (refereegranskat)abstract
- The selective forces that drive the evolution of cooperation have been intensely debated. Evolutionary transitions to cooperative breeding, a complex form of cooperation, have been hypothesized to be linked to low degrees of promiscuity, which increases intragroup relatedness and the indirect (that is, kin selected) benefits of helping. However, ecological factors also promote cooperative breeding, and may be more important than relatedness in some contexts. Identifying the key evolutionary drivers of cooperative breeding therefore requires an integrated assessment of these hypotheses. Here we show, using a phylogenetic framework that explicitly evaluates mating behaviours and ecological factors, that evolutionary transitions to cooperative breeding in cichlid fishes were not associated with social monogamy. Instead, group living, biparental care and diet type directly favoured the evolution of cooperative breeding. Our results suggest that cichlid fishes exhibit an alternative path to the evolution of complex societies compared to other previously studied vertebrates, and these transitions are driven primarily by direct fitness benefits.
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| 2. |
- Fitzpatrick, John L., et al.
(författare)
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Female promiscuity promotes the evolution of faster sperm in cichlid fishes
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:4, s. 1128-1132
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Tidskriftsartikel (refereegranskat)abstract
- Sperm competition, the contest among ejaculates from rival males to fertilize ova of a female, is a common and powerful evolutionary force influencing ejaculate traits. During competitive interactions between ejaculates, longer and faster spermatozoa are expected to have an edge; however, to date, there has been mixed support for this key prediction from sperm competition theory. Here, we use the spectacular radiation of cichlid fishes from Lake Tanganyika to examine sperm characteristics in 29 closely related species. We provide phylogenetically robust evidence that species experiencing greater levels of sperm competition have faster-swimming sperm. We also show that sperm competition selects for increases in the number, size, and longevity of spermatozoa in the ejaculate of a male, and, contrary to expectations from theory, we find no evidence of trade-offs among sperm traits in an interspecific analysis. Also, sperm swimming speed is positively correlated with sperm length among, but not within, species. These different responses to sperm competition at intra-and interspecific levels provide a simple, powerful explanation for equivocal results from previous studies. Using phylogenetic analyses, we also reconstructed the probable evolutionary route of trait evolution in this taxon, and show that, in response to increases in the magnitude of sperm competition, the evolution of sperm traits in this clade began with the evolution of faster (thus, more competitive) sperm.
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| 3. |
- McCallum, Erin S., et al.
(författare)
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Exposure to wastewater effluent affects fish behaviour and tissue-specific uptake of pharmaceuticals
- 2017
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Ingår i: Science of the Total Environment. - Amsterdam : Elsevier. - 0048-9697 .- 1879-1026. ; 605-606, s. 578-588
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Tidskriftsartikel (refereegranskat)abstract
- Pharmaceutical active compounds (PhACs) are increasingly being reported in wastewater effluents and surface waters around the world. The presence of these products, designed to modulate human physiology and behaviour, has created concern over whether PhACs similarly affect aquatic organisms. Though laboratory studies are beginning to address the effects of individual PhACs on fish behaviour, few studies have assessed the effects of exposure to complex, realistic wastewater effluents on fish behaviour. In this study, we exposed a wild, invasive fish species—the round goby (Neogobius melanostomus)—to treated wastewater effluent (0%, 50% or 100% effluent dilutions) for 28 days. We then determined the impact of exposure on fish aggression, an important behaviour for territory acquisition and defense. We found that exposure to 100% wastewater effluent reduced the number of aggressive acts that round goby performed. We complimented our behavioural assay with measures of pharmaceutical uptake in fish tissues. We detected 11 of 93 pharmaceutical compounds that we tested for in round goby tissues, and we found that concentration was greatest in the brain followed by plasma, then gonads, then liver, and muscle. Fish exposed to 50% and 100% effluent had higher tissue concentrations of pharmaceuticals and concentrated a greater number of pharmaceutical compounds compare to control fish exposed to no (0%) effluent. Exposed fish also showed increased ethoxyresorufin-O-deethylase (EROD) activity in liver tissue, suggesting that fish were exposed to planar halogenated/polycyclic aromatic hydrocarbons (PHHs/PAHs) in the wastewater effluent. Our findings suggest that fish in effluent-dominated systems may have altered behaviours and greater tissue concentration of PhACs. Moreover, our results underscore the importance of characterizing exposure to multiple pollutants, and support using behaviour as a sensitive tool for assessing animal responses to complex contaminant mixtures, like wastewater effluent.
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| 4. |
- Miller, Jessica S., et al.
(författare)
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Sperm maturation and male tactic-specific differences in ejaculates in the plainfin midshipman fish Porichthys notatus
- 2019
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 94:3, s. 434-445
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Tidskriftsartikel (refereegranskat)abstract
- Using the plainfin midshipman fish Porichthys notatus, a species with alternative reproductive tactics (ARTs), we investigated how sperm maturation shapes sperm competitive abilities. We compared sperm performance and morphology before and after final sperm maturation by sampling sperm from the testes and stripped ejaculates of guarders and sneakers. In accordance with sperm competition risk theory, ejaculates from sneaker males had three times as much sperm as ejaculates from guarder males and sneaker males produced faster swimming sperm than guarder males, but this was only the case after final sperm maturation had occurred. Additionally, fully mature sperm found in ejaculates had larger heads and midpieces than sperm found in the testes. These results emphasize the important role played by non-sperm components of an ejaculate in mediating sperm performance and potentially also morphology.
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| 5. |
- Saaristo, Minna, et al.
(författare)
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Direct and indirect effects of chemical contaminants on the behaviour, ecology and evolution of wildlife
- 2018
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : ROYAL SOC. - 0962-8452 .- 1471-2954. ; 285:1885
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Forskningsöversikt (refereegranskat)abstract
- Chemical contaminants (e.g. metals, pesticides, pharmaceuticals) are changing ecosystems via effects on wildlife. Indeed, recent work explicitly performed under environmentally realistic conditions reveals that chemical contaminants can have both direct and indirect effects at multiple levels of organization by influencing animal behaviour. Altered behaviour reflects multiple physiological changes and links individual-to population-level processes, thereby representing a sensitive tool for holistically assessing impacts of environmentally relevant contaminant concentrations. Here, we show that even if direct effects of contaminants on behavioural responses are reasonably well documented, there are significant knowledge gaps in understanding both the plasticity (i.e. individual variation) and evolution of contaminant-induced behavioural changes. We explore implications of multi-level processes by developing a conceptual framework that integrates direct and indirect effects on behaviour under environmentally realistic contexts. Our framework illustrates how sublethal behavioural effects of contaminants can be both negative and positive, varying dynamically within the same individuals and populations. This is because linkages within communities will act indirectly to alter and even magnify contaminant-induced effects. Given the increasing pressure on wildlife and ecosystems from chemical pollution, we argue there is a need to incorporate existing knowledge in ecology and evolution to improve ecological hazard and risk assessments.
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| 6. |
- Stanbrook, Emily, et al.
(författare)
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The evolution of monogamy in cichlids and marine reef fishes
- 2022
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Although several hypotheses have been proposed to explain the emergence of social monogamy, its origin is still intensely debated. Monogamy has many potential drivers, but evolutionary causality among them remains unclear. Using phylogenetic comparative methods within a Bayesian framework we explored the evolution of monogamy in cichlids and in marine reef fishes because, while both groups are characterised by unusually high incidence of social monogamy, they face very different ecological challenges. For each group, we examined four classic hypotheses that explain the evolution of monogamy: female dispersal, male mate guarding, female–female intolerance, and the biparental care hypotheses. We also explored whether the ecological traits of diet and shelter use are evolutionarily coupled with these hypotheses or with monogamy. First, we found that the evolution of monogamy was predicted by male territoriality in cichlids and simultaneous male and female territoriality in marine reef fishes. We suggest that these results provide support for the male mate guarding hypothesis in cichlids and female–female intolerance hypothesis in marine reef fishes. Second, we demonstrate clear evidence against the biparental care hypothesis, as biparental care was a consequence, not a cause, of monogamy in our analyses. Third, as female dispersal drove the loss of monogamy in both cichlids and marine reef fishes, this suggests the female dispersal hypothesis is not driving the evolution of monogamy in either group. These findings in two highly-monogamous fish taxa largely support prior findings from primate and bird comparative studies and provide novel large-scale evidence for a link between mate guarding and the evolution of monogamy.
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| 7. |
- Svensson, Ola, 1971-
(författare)
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Sexual selection in Pomatoschistus – nests, sperm competition, and paternal care
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sexual selection arises through variation in reproductive success. This thesis investigates different aspects important in sexual selection, namely nest building, sperm competition, paternity and paternal care, and their mutual interrelationships. In the studied species, the sand goby (Pomatoschistus minutus) and the common goby (Pomatoschistus microps), sperm competition did arise when small males, so called sneakers, sneaked into other males nests and released sperm. They seemed to use female behaviour as their prime cue for a sneaking opportunity. However, also nest-holders, both with and without eggs, were found to fertilize eggs in the nests of other males.Clearly, nest-holding males tried to prevent other males from spreading their sperm in their nests, since they showed aggression towards such males. A nest building experiment indicated that the small nest-openings found in the sneaker male treatment were sexually selected through protection against sneaking or by female choice. Yet, no behavioural or genetical support for the hypothesis that the nest functions as a physical or visual defence, or that sneaker males prefer to sneak upon nests with wide nest-openings, were found in the other studies. Still, individual nest-holding males showed a higher mucus preparation effort inside the nest in the presence of a sneaker male than when alone. In close relatives, such mucus contains sperm, suggesting an importance in sperm competition. However, the mucus may also have pheromone and anti-bacterial functions and may constitute a mating effort, as found in other gobies. Both a behavioural and a mate choice experiment suggested that the males were not less eager to spawn in the presence of a sneaker male.Sneak intrusion did not affect nest defence, fanning or filial cannibalism, nor had paternity an effect on filial cannibalism. This and various life history aspects, together with the fact that the parasitic male only fertilized a fraction of the clutches, would predict females to ignore sneaker males. This was also the case, as the presence of sneaker males was found not to affect female spawning decision. Still, several females spawned in two nests, which coincided with parasitic spawnings, suggesting a cost of disturbance for the females and thus a substantial cost to the nest-holding males in terms of lost mating success. However, females paid attention to other traits in their choice of mate since spawning was associated with sand volume of the nest, but not with nest-opening width. Also, female (but not male) courtship was correlated with partial clutch filial cannibalism, indicating that females are able to anticipate future male cannibalism.In a partial correlation of nest opening, sand volume, male courtship display, displacement fanning and male size, a large number of traits were correlated both positively and negatively with regard to how we may expect them to be appreciated by females. For instance, males which fan well also build large nests or display intensely (but not both). Together with all the other results of this thesis, this shows the entangled selection pressures working on breeding animals, as well as the different male and female tactics employed to maximize their reproduction.
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| 8. |
- Ågerstrand, Marlene, et al.
(författare)
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Emerging investigator series : use of behavioural endpoints in the regulation of chemicals
- 2020
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Ingår i: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 22:1, s. 49-65
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Tidskriftsartikel (refereegranskat)abstract
- Interest in behavioural ecotoxicology is growing, partly due to technological and computational advances in recording behaviours but also because of improvements of detection capacity facilitating reporting effects at environmentally relevant concentrations. The peer-reviewed literature now contains studies investigating the effects of chemicals, including pesticides and pharmaceuticals, on migration, dispersal, aggression, sociability, reproduction, feeding and anti-predator behaviours in vertebrates and invertebrates. To understand how behavioural studies could be used in regulatory decision-making we: (1) assessed the legal obstacles to using behavioural endpoints in EU chemicals regulation; (2) analysed the known cases of use of behavioural endpoints in EU chemicals regulation; and (3) provided examples of behavioural endpoints of relevance for population level effects. We conclude that the only legal obstacle to the use of behavioural endpoints in EU chemicals regulation is whether an endpoint is considered to be relevant at the population level or not. We also conclude that ecotoxicity studies investigating behavioural endpoints are occasionally used in the EU chemicals regulation, and underscore that behavioural endpoints can be relevant at the population level. To improve the current use of behavioural studies in regulatory decision-making contribution from all relevant stakeholders is required. We have the following recommendations: (1) researchers should conduct robust, well-designed and transparent studies that emphasize the relevance of the study for regulation of chemicals; (2) editors and scientific journals should promote detailed, reliable and clearly reported studies; (3) regulatory agencies and the chemical industry need to embrace new behavioural endpoints of relevance at the population level.
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