Artificial size selection experiment reveals telomere length dynamics and fitness consequences in a wild passerine

Changes in telomere dynamics could underlie life-history trade-offs among growth, size and longevity, but our ability to quantify such mechanistic processes in natural, unmanipulated populations is limited. We investigated how 4 years of artificial selection for either larger or smaller body size affected early-life telomere length in two insular populations of wild house sparrows. A negative correlation between telomere length and structural size was evident under both selection regimes. The study also revealed that male sparrows had longer telomeres than females, after controlling for size, and there was a significant negative effect of harsh weather conditions on telomere length. The long-term fitness consequences of these changes in early-life telomere length induced by the artificial size selection were explored over a period of 11 years. These analyses indicated disruptive selection on telomere length because both short and long early-life telomere length tended to be associated with the lowest mortality rates and highest life expectancy. There was also weak evidence for a negative association between telomere length and annual reproductive success, but only in the population where body size was increased experimentally. Our results suggest that natural selection for optimal body size in wild animals will affect early-life telomere length during growth, which is known to be linked to longevity in birds, but also that the importance of telomeres for long-term somatic maintenance and fitness is complex in a wild bird species.

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Nestling telomere shortening, but not telomere length, reflects developmental stress and predicts survival in wild birds

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.3287 ◽

2014 ◽

Vol 281 (1785) ◽

pp. 20133287 ◽

Cited By ~ 130

Author(s):

Jelle J. Boonekamp ◽

G. A. Mulder ◽

H. Martijn Salomons ◽

Cor Dijkstra ◽

Simon Verhulst

Keyword(s):

Telomere Length ◽

Brood Size ◽

Developmental Stress ◽

Free Living ◽

Telomere Shortening ◽

Developmental Effects ◽

Fitness Consequences ◽

Developmental Conditions ◽

Fledgling Mass

Developmental stressors often have long-term fitness consequences, but linking offspring traits to fitness prospects has remained a challenge. Telomere length predicts mortality in adult birds, and may provide a link between developmental conditions and fitness prospects. Here, we examine the effects of manipulated brood size on growth, telomere dynamics and post-fledging survival in free-living jackdaws. Nestlings in enlarged broods achieved lower mass and lost 21% more telomere repeats relative to nestlings in reduced broods, showing that developmental stress accelerates telomere shortening. Adult telomere length was positively correlated with their telomere length as nestling ( r = 0.83). Thus, an advantage of long telomeres in nestlings is carried through to adulthood. Nestling telomere shortening predicted post-fledging survival and recruitment independent of manipulation and fledgling mass. This effect was strong, with a threefold difference in recruitment probability over the telomere shortening range. By contrast, absolute telomere length was neither affected by brood size manipulation nor related to survival. We conclude that telomere loss, but not absolute telomere length, links developmental conditions to subsequent survival and suggest that telomere shortening may provide a key to unravelling the physiological causes of developmental effects on fitness.

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Anthropogenic activities are associated with shorter telomeres in chicks of Adélie penguin (Pygoscelis adeliae)

Polar Biology ◽

10.1007/s00300-021-02892-7 ◽

2021 ◽

Author(s):

Jilda Alicia Caccavo ◽

Thierry Raclot ◽

Timothée Poupart ◽

Yan Ropert-Coudert ◽

Frédéric Angelier

Keyword(s):

Telomere Length ◽

Human Activity ◽

Anthropogenic Activities ◽

Adélie Penguin ◽

Pygoscelis Adeliae ◽

Adelie Penguin ◽

Fitness Consequences ◽

Length Analysis ◽

The Impact ◽

The Relationship

AbstractDefining the impact of anthropogenic stressors on Antarctic wildlife is an active aim for investigators. Telomeres represent a promising molecular tool to investigate the fitness of wild populations, as their length may predict longevity and survival. We examined the relationship between telomere length and human exposure in Adélie penguin chicks (Pygoscelis adeliae) from East Antarctica. Telomere length was compared between chicks from areas with sustained human activity and on neighboring protected islands with little or no human presence. Adélie penguin chicks from sites exposed to human activity had significantly shorter telomeres than chicks from unexposed sites in nearby protected areas, with exposed chicks having on average 3.5% shorter telomeres than unexposed chicks. While sampling limitations preclude our ability to draw more sweeping conclusions at this time, our analysis nonetheless provides important insights into measures of colony vulnerability. More data are needed both to understand the proximate causes (e.g., stress, feeding events) leading to shorter telomeres in chicks from human exposed areas, as well as the fitness consequences of reduced telomere length. We suggest to further test the use of telomere length analysis as an eco-indicator of stress in wildlife among anthropized sites throughout Antarctica.

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Dealing with hot rocky environments: Critical thermal maxima and locomotor performance in Leptodactylus lithonaetes (Anura: Leptodactylidae)

Herpetological Journal ◽

10.33256/hj29.3.155161 ◽

2019 ◽

pp. 155-161 ◽

Cited By ~ 1

Author(s):

Ivan Beltran

Keyword(s):

Environmental Temperature ◽

Extreme Temperature ◽

Effect Of Temperature ◽

Maximum Speed ◽

Locomotor Performance ◽

Extreme Temperatures ◽

Physiological Limits ◽

Fitness Consequences ◽

Thermal Maximum ◽

Environmental Temperatures

Environmental temperature has fitness consequences on ectotherm development, ecology and behaviour. Amphibians are especially vulnerable because thermoregulation often trades with appropriate water balance. Although substantial research has evaluated the effect of temperature in amphibian locomotion and physiological limits, there is little information about amphibians living under extreme temperature conditions. Leptodactylus lithonaetes is a frog allegedly specialised to forage and breed on dark granitic outcrops and associated puddles, which reach environmental temperatures well above 40 ˚C. Adults can select thermally favourable microhabitats during the day while tadpoles are constrained to rock puddles and associated temperature fluctuations; we thus established microhabitat temperatures and tested whether the critical thermal maximum (CTmax) of L. lithonaetes is higher in tadpoles compared to adults. In addition, we evaluated the effect of water temperature on locomotor performance of tadpoles. Contrary to our expectations, puddle temperatures were comparable and even lower than those temperatures measured in the microhabitats used by adults in the daytime. Nonetheless, the CTmax was 42.3 ˚C for tadpoles and 39.7 ˚C for adults. Regarding locomotor performance, maximum speed and maximum distance travelled by tadpoles peaked around 34 ˚C, approximately 1 ˚C below the maximum puddle temperatures registered in the puddles. In conclusion, L. lithonaetes tadpoles have a higher CTmax compared to adults, suggesting a longer exposure to extreme temperatures that lead to maintain their physiological performance at high temperatures. We suggest that these conditions are adaptations to face the strong selection forces driven by this granitic habitat.

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