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  • Griffith, Simon C., et al. (författare)
  • Variation in reproductive success across captive populations: Methodological differences, potential biases and opportunities
  • 2017
  • Ingår i: Ethology. - : Wiley-Blackwell. - 1439-0310. ; 123:1, s. 1-29
  • Tidskriftsartikel (refereegranskat)abstract
    • Our understanding of fundamental organismal biology has been disproportionately influenced by studies of a relatively small number of ‘model’ species extensively studied in captivity. Laboratory populations of model species are commonly subject to a number of forms of past and current selection that may affect experimental outcomes. Here, we examine these processes and their outcomes in one of the most widely used vertebrate species in the laboratory – the zebra finch (Taeniopygia guttata). This important model species is used for research across a broad range of fields, partly due to the ease with which it can be bred in captivity. However despite this perceived amenability, we demonstrate extensive variation in the success with which different laboratories and studies bred their subjects, and overall only 64% of all females that were given the opportunity, bred successfully in the laboratory. We identify and review several environmental, husbandry, life-history and behavioural factors that potentially contribute to this variation. The variation in reproductive success across individuals could lead to biases in experimental outcomes and drive some of the heterogeneity in research outcomes across studies. The zebra finch remains an excellent captive animal system and our aim is to sharpen the insight that future studies of this species can provide, both to our understanding of this species and also with respect to the reproduction of captive animals more widely. We hope to improve systematic reporting methods and that further investigation of the issues we raise will lead both to advances in our fundamental understanding of avian reproduction as well as to improvements in future welfare and experimental efficiency.
  • Salmon, Pablo, et al. (författare)
  • Effects of the Urban Environment on Oxidative Stress in Early Life : Insights from a Cross-fostering Experiment
  • 2018
  • Ingår i: Integrative and Comparative Biology. - : Oxford University Press. - 1557-7023. ; , s. 986-994
  • Tidskriftsartikel (refereegranskat)abstract
    • As urban areas expand rapidly worldwide, wildlife is exposed to a wide range of novel environmental stressors, such as increased air pollution and artificial light at night. Birds in highly polluted and/or urbanized habitats have been found to have increased antioxidant protection, which is likely important to avoid accumulation of oxidative damage, which can have negative fitness consequences. Yet, the current knowledge about the ontogeny of antioxidant protection in urban areas is limited; i.e., is the capacity to up-regulate the antioxidant defences already established during pre-natal development, or does it manifest itself during post-natal development? We cross-fostered great tit (Parus major) nestlings within and between urban and rural habitats, to determine if oxidative stress (measured as non-enzymatic total antioxidant capacity, superoxide dismutase (SOD), and plasma lipid peroxidation) is affected by habitat of origin and/or by habitat of rearing. The results demonstrate that being reared in the urban environment triggers an increase in SOD (an intracellular, enzymatic antioxidant) independent of natal habitat. Oxidative damage increased with hatching date in urban-reared nestlings, but there was little seasonal change in rural-reared nestlings. Total antioxidant capacity was neither affected by habitat of rearing or habitat of origin, but we observed a decline with hatching date in both rearing habitats. Taken together, our results support the growing evidence that the urban environment induces a direct plastic adjustment in antioxidant protection, but that up-regulation is not sufficient to avoid increased oxidative damage in late-hatched broods. Future studies should explore the underlying causes for this effect in late-hatched broods and whether it has any negative long-term implications, both at the individual- and the population level.
  • Yuvaraj, Jothi Kumar, et al. (författare)
  • Characterization of odorant receptors from a non-ditrysian moth, Eriocrania semipurpurella sheds light on the origin of the sex pheromone receptors in Lepidoptera
  • 2017
  • Ingår i: Molecular biology and evolution. - : Oxford University Press. - 0737-4038. ; 34:11, s. 2733-2746
  • Tidskriftsartikel (refereegranskat)abstract
    • Pheromone receptors (PRs) are essential in moths to detect sex pheromones for mate finding. However, it remainsunknown from which ancestral proteins these specialized receptors arose. The oldest lineages of moths, so-callednon-ditrysian moths, use short-chain pheromone components, secondary alcohols, or ketones, so called Type 0 pheromonesthat are similar to many common plant volatiles. It is, therefore, possible that receptors for these ancestralpheromones evolved from receptors detecting plant volatiles. Hence, we identified the odorant receptors (ORs) from anon-ditrysian moth, Eriocrania semipurpurella (Eriocraniidae, Lepidoptera), and performed functional characterizationof ORs using HEK293 cells. We report the first receptors that respond to Type 0 pheromone compounds; EsemOR3displayed highest sensitivity toward (2S, 6Z)-6-nonen-2-ol, whereas EsemOR5 was most sensitive to the behavioralantagonist (Z)-6-nonen-2-one. These receptors also respond to plant volatiles of similar chemical structures, but withlower sensitivity. Phylogenetically, EsemOR3 and EsemOR5 group with a plant volatile-responding receptor from thetortricid moth Epiphyas postvittana (EposOR3), which together reside outside the previously defined lepidopteran PRclade that contains the PRs from more derived lepidopteran families. In addition, one receptor (EsemOR1) that falls atthe base of the lepidopteran PR clade, responded specifically to b-caryophyllene and not to any other additional plant orpheromone compounds. Our results suggest that PRs for Type 0 pheromones have evolved from ORs that detectstructurally-related plant volatiles. They are unrelated to PRs detecting pheromones inmore derived Lepidoptera, which,in turn, also independently may have evolved a novel function from ORs detecting plant volatiles.
  • Andreasson, Fredrik, et al. (författare)
  • Experimentally increased nest temperature affects body temperature, growth and apparent survival in blue tit nestlings
  • Ingår i: Journal of Avian Biology. - : Federation of European Neuroscience Societies and Blackwell Publishing Ltd. - 0908-8857. ; 49:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The thermal environment experienced by birds during early postembryonic development may be an important factor shaping growth and survival. However, few studies have directly manipulated nest temperature (T n) during the nestling phase, and none have measured the consequences of experimental heat stress on nestlings’ body temperature (T b). It is therefore not known to what extent any fitness consequences of development in a thermally challenging environment arise as a direct, or indirect, effect of heat stress. We, therefore, studied how experimentally increased T n affected T b in 8–12 d old blue tit Cyanistes caeruleus nestlings, to investigate if increased thermoregulatory demands to maintain normothermic T b influenced nestling growth and apparent long-term survival. Nestlings in heated nest-boxes had significantly higher T b compared to unheated nestlings during most of the experimental period. Yet, despite facing T n  50°C (as measured in the bottom of the nest cup below the nestlings), the highest nestling T b recorded was 43.8°C with nestlings showing evidence of controlled facultative hyperthermia without any increased nestling mortality in heated nests. However, body mass gain was lower in these nestlings compared to nestlings from control nest-boxes. Contrary to our prediction, a larger proportion of nestlings from heated nest-boxes were recaptured during their first winter, or subsequently recruited into the breeding population as first- or second-year breeders. This result should, however, be treated with caution because of low recapture rates. This study highlights the importance of the thermal environment during nestling development, and its role in shaping both growth patterns and possibly also apparent survival.
  • Goldberg, Rebecca L., et al. (författare)
  • The costs and benefits of paternal care in fish : a meta-analysis
  • 2020
  • Ingår i: Proceedings. Biological sciences. - : Royal Society. - 1471-2954. ; 287:1935
  • Tidskriftsartikel (refereegranskat)abstract
    • Male-only parental care, while rare in most animals, is a widespread strategy within teleost fish. The costs and benefits to males of acting as sole carer are highly variable among fish species making it challenging to determine the selective pressures driving the evolution of male-only care to such a high prevalence. We conducted a phylogenetic meta-analysis to examine the costs and benefits of paternal care across fish species. We found no evidence that providing care negatively affects male condition. In contrast with other taxa, we also found limited evidence that male care has evolved as a strategy to improve offspring survival. Instead, we found that males already caring for a brood are preferred by females and that this preference is strongest in those species in which males work harder to care for larger broods. Thus, in fish, investment in offspring care does not constrain a male's mating success but rather augments it, suggesting that the relatively high prevalence of male-only care in fish may be in part explained by sexual selection through female preference for caring males.
  • Gonzalez, Elena G., et al. (författare)
  • Phylogeography and Population Genetic Analyses in the Iberian Toothcarp (Aphanius iberus Valenciennes, 1846) at Different Time Scales
  • 2018
  • Ingår i: Journal of Heredity. - : Oxford University Press. - 0022-1503. ; 109:3, s. 253-263
  • Tidskriftsartikel (refereegranskat)abstract
    • Secondary freshwater fish species inhabiting fluctuating and extreme environments are susceptible to changes in dispersion, effective population size, and genetic structure. The Iberian toothcarp Aphanius iberus is an endemic cyprinodontid of the Iberian Peninsula restricted to brackish water of salt marshes and coastal lagoons on the eastern Spanish Mediterranean coast. In this study, we analyzed mitochondrial cytochrome b (cyt b) DNA and microsatellite variation to evaluate ways in which the processes of extinction, dispersal, and colonization of A. iberus across its geographic distribution have affected its population genetic structure over time and space. The A. iberus network reconstruction indicated subtle levels of phylogeographic structuring.This, combined with substantial mitochondrial DNA (mtDNA) genetic diversity, suggests that Pleistocene glaciations had a lesser effect on the demographic structure of its populations than was the case for Iberian freshwater species with a similar distribution. Haplotype network, hierarchical analysis of molecular variance, and pairwise ΦST comparisons involving some Levantine samples showed a relatively high degree of mtDNA differentiation, which could be explained by historical isolation of the Villena Lagoon population. Conversely, significant genetic differentiation that follows an isolation-by-distance pattern, and a reduction in Ne though time was detected with microsatellites, suggesting extensive habitat fragmentation on the Mediterranean coast of the Iberian Peninsula over the past hundreds of years. At a smaller geographical scale (Mar Menor Lagoon), habitat fragmentation, probably due to human activity, appears to have resulted in substantially reduced migration and increased genetic drift, as shown by expanded genetic differentiation of populations.Subject areas: Population structure and phylogeography, Conservation
  • Kozłowski, Tomasz M (författare)
  • Fish Lenses : Anatomy and Optics
  • 2018
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • I have investigated some of the biological regulatory mechanisms governing the development of crystalline lenses. I used fish as model animals because they possess optically interesting lenses, while the geometrical simplicity of fish lenses allows for studies that are difficult or impossible with the lenses of other animals.First we have investigated lens optical plasticity by measuring longitudinal spherical aberration in light and dark adapted fish of two species, Atlantic and Polar cod. We noticed that Atlantic cod, native to regions with daily light/dark changes responded to light/dark adaptation by changing the optics of its lens, whereas the optics of Polar cod, living in the polar region, was unchanged on a daily basis (Paper I). However, we observed that the optics of the Polar cod lens changed annually between seasons corresponding to polar day and night (unpublished data). Our findings can be explained by the existence of two different mechanisms controlling the optics of fish lenses. A short-term one adapting the lenses to daily light/dark cycles (Atlantic cod) and a long-term one evolved for coping with long polar days and nights (Polar cod).The second project involved investigation of the osmolality of fish larvae body fluids. We tested two levels of osmolality in two different ways. The first one involved measuring the rate of optical deterioration of excised fish lenses placed in different immersion media, the second one the quality of a whole eye fixation. In both cases, lower osmolality gave better results for fish larvae. The optical quality of larval lenses deteriorated slower and fixation preserved the larval eye in a more natural shape (Paper II). We concluded that zebrafish larvae have lower osmolality in their bodies than adult fish.The third project was dedicated to the investigation of the cellular structure of fish lenses. First, we developed a method to visualize an equatorial cross-sections of adult fish lenses. Than we used the method to examine lenses in two size groups of fish of the same species. We measured lens fiber thickness in four relative radial positions in the lens. Our measurements showed that fish lens fiber cells have the same thickness along the radius of the lens and in both size groups. The average thickness was much lower than in other vertebrates (Paper III).We followed up that study by measuring full thickness profile along the lens radius in nine fish species. The thickness of a fiber was independent from its radial position in the lens in all but one species. We observed that the average fiber thickness depends on species. Additionally, we developed a model for calculating historical lens fiber thicknesses necessary for the cells to reach their current refractive indices and thicknesses by cell compaction. The model showed that the cells would have to lose 66% of their volumes to reach their current sizes. This unlikely number and the constancy of cell thickness suggest that a different mechanism is at work. (Paper IV). Based on the findings from both papers, we conclude that, at least in fish, protein is transported inwards between denucleated fibers in the growing lens. The cells in the peripheral lens layers have synthetic capabilities and are most likely the source of those proteins.
  • Lewden, Agnès, et al. (författare)
  • Body temperature responses to handling stress in wintering Black-capped Chickadees (Poecile atricapillus L.)
  • 2017
  • Ingår i: Physiology & Behavior. - : Elsevier. - 1873-507X. ; 179, s. 49-54
  • Tidskriftsartikel (refereegranskat)abstract
    • Body temperature variation in response to acute stress is typically characterized by peripheral vasoconstriction and a concomitant increase in core body temperature (stress-induced hyperthermia). It is poorly understood how this response differs between species and within individuals of the same species, and how it is affected by the environment. We therefore investigated stress-induced body temperature changes in a non-model species, the Black-capped Chickadee, in two environmental conditions: outdoors in low ambient temperature (mean: − 6.6 °C), and indoors, in milder ambient temperature close to thermoneutrality (mean: 18.7 °C). Our results show that the change in body temperature in response to the same handling stressor differs in these conditions. In cold environments, we noted a significant decrease in core body temperature (− 2.9 °C), whereas the response in mild indoor conditions was weak and non-significant (− 0.6 °C). Heat loss in outdoor birds was exacerbated when birds were handled for longer time. This may highlight the role of behavioral thermoregulation and heat substitution from activity to body temperature maintenance in harsh condition. Importantly, our work also indicates that changes in the physical properties of the bird during handling (conductive cooling from cold hands, decreased insulation from compression of plumage and prevention of ptiloerection) may have large consequences for thermoregulation. This might explain why females, the smaller sex, lost more heat than males in the experiment. Because physiological and physical changes during handling may carry over to affect predation risk and maintenance of energy balance during short winter days, we advice caution when designing experimental protocols entailing prolonged handling of small birds in cold conditions.
  • Nilsson, Jan-Åke, et al. (författare)
  • Testing the heat dissipation limit theory in a breeding passerine
  • 2018
  • Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : Royal Society. - 1471-2954. ; 285:1878
  • Tidskriftsartikel (refereegranskat)abstract
    • The maximum work rate of animals has recently been suggested to be determined by the rate at which excess metabolic heat generated during work can be dissipated (heat dissipation limitation (HDL) theory). As a first step towards testing this theory in wild animals, we experimentally manipulated brood size in breeding marsh tits (Poecile palustris) to change their work rate. Parents feeding nestlings generally operated at above-normal body temperatures. Body temperature in both males and females increased with maximum ambient temperature and with manipulated work rate, sometimes even exceeding 45°C, which is close to suggested lethal levels for birds. Such high body temperatures have previously only been described for birds living in hot and arid regions. Thus, reproductive effort in marsh tits may potentially be limited by the rate of heat dissipation. Females had lower body temperatures, a possible consequence of their brood patch serving as a thermal window facilitating heat dissipation. Because increasing body temperatures are connected to somatic costs, we suggest that the HDL theory may constitute a possible mediator of the trade-off between current and future reproduction. It follows that globally increasing, more stochastic, ambient temperatures may restrict the capacity for sustained work of animals in the future.
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