Insights into life history theory: a brood size manipulation on a southern hemisphere species,Tachycineta leucorrhoa, reveals a fast pace of life

Abstract

Life history traits exhibit substantial geographical variation associated with the pace of life. Species with a slow pace are expected to invest more in their future/residual reproductive value and are more common at tropical latitudes, whereas species from high latitudes, with a faster pace, are expected to prioritize the current reproductive eff ort. Most evidence supporting this pattern comes from studies conducted in tropical and north temperate species; very little is known about patterns in southern South American species. Here, we describe the life history of a southern swallow Tachycineta leucorrhoa and use an experimental approach to test their breeding strategy over four breeding seasons. We manipulated brood size for 105 nests of white-rumped swallows to measure whether costs of reproduction were borne by adults or nestlings as alternative selection strategies towards maintaining residual or current reproductive value. Adults increased their feeding eff ort in enlarged broods, at least enough to maintain nestlings ' development/growth. In addition, adults decreased the number of visits to the nest (without having a negative eff ect on nestlings) in reduced broods. We did not detect diff erences in fl edging success among treatments, suggesting there were no diff erences in nestlings ' survival. However, enlarged broods more frequently incurred in complete nest failure, suggesting only some adults were able to cope with increased costs of reproduction. We conclude this species is characterized by a fast pace of life similar to their northern congeners and less like its tropical ones. Th is is one of the fi rst studies to use an experimental approach to test a life history hypothesis of pace of life using data from a southern South American species. We encourage researches to include southern species when evaluating latitudinal variations as we still do not have enough evidence to assume all southern subtropical species are indeed similar to tropical ones.

Anti-predator responses in the Chilean Swallow Tachycineta leucopyga breeding in northwest Patagonia

“…It is possible that Chilean Swallows invest as much energy in defending their nests from the beginning of the breeding attempt as they do later on, maintaining the level of antipredator behaviour throughout the entire nestling period. Southern Hemisphere Tachycineta swallows seem to have more dedicated parental care than Northern Hemisphere congeners, as shown by the higher feeding rates of White-Rumped Swallow, compared to the Tree Swallow (Bulit et al 2014), and to the active role of Chilean Swallow males during incubation (Ospina et al 2015).…”

Ecological opportunities and individual condition as predictors of extra-pair paternity in a south-temperate swallow (Tachycineta leucorrhoa)

“…() and Bulit et al. (). For each nest box, we recorded latitude and longitude (± 3 m) using a GPS unit (Garmin 76, Garman International, Olathe, KS).…”

The metabolic rate of cultured muscle cells from hybrid Coturnix quail is intermediate to that of muscle cells from fast-growing and slow-growing Coturnix quail

“…Growth rate, a fundamental life history trait, varies 30-fold across all bird species (Ricklefs 1984;Williams et al 2007;Robinson et al 2010;Dmitriew 2011). Although an individual's growth rate may be plastic in response to environmental variables, the growth rate of an organism is genetically regulated, and may be a target for natural selection (Dmitriew 2011;Jimenez et al 2014c;Bulit et al 2014). As growth rate sets the pace for development, it can also influence time and energy budgets of reproduction that may result in changes in fitness (Ricklefs 2010).…”

“…We reared chicks from two hybrid lines with reciprocal parental configurations for growth rate to explore the effect of maternally inherited mitochondrial DNA on rates of growth and metabolism. Growth rates of chicks, cellular basal oxygen consumption, glycolytic flux, and mitochondrial volume in myoblasts from chicks from both reciprocal crosses were intermediate to the fast and Communicated by I. D. Hume. where species on the "slow" end are characterized by low metabolic rates, slow growth rates, greater longevity, and lower investment in reproduction, whereas species on the "fast" end are characterized by higher metabolic rates, faster growth rates, and greater investment in reproduction (Ricklefs and Wikelski 2002;Wiersma et al 2007;Londono 2014;Bulit et al 2014). Growth rate, a fundamental life history trait, varies 30-fold across all bird species (Ricklefs 1984;Williams et al 2007;Robinson et al 2010;Dmitriew 2011).…”