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Argentine ants harm nestlings of the blue tit

The consequences of ant invasions on ecosystems may only become apparent after long periods. In addition, predicting how sensitive native fauna will respond is only possible if the underlying proximate mechanisms of their impact are identified. The attraction of the native and invasive ant community to artificial bird nests was studied, together with reproduction of a wild native songbird over five consecutive breeding seasons in relation to the presence of an invasive ant species. Biometric, reproductive and individual blood parameters of great tits Parus major breeding in invaded as compared to uninvaded sites by Argentine ants Linepithema humile were analysed. Great tits bred preferably in uninvaded territories by the Argentine ant. Moreover, Argentine ants were more abundant at nests in invaded sites, than any native ant species were at uninvaded sites. Further, Argentine ants recruited at the artificial nests more intensively and responded to a larger variety of nest (intact eggs, cracked eggs, faeces, and cracked eggs plus faeces) contents than native species. Although breeding success and adult condition did not vary in relation to invasion status, offspring quality was negatively affected by the presence of Argentine ants. Nestlings reared in invaded sites were lighter, with lower wing/tarsus length ratio and had a reduced nutritional condition and altered oxidative stress balance as measured from several blood parameters. The interspersed distribution and small distance between invaded versus uninvaded territories suggest that ant presence affects nestling condition through direct interference at the nest. These results highlight the importance of evaluating the proximate effects like physiological parameters of the native fauna, when studying invasive ant-native bird interactions. informacion[at] Álvarez et al (2020) Breeding consequences for a songbird nesting in Argentine ant' invaded land. Biol Invasions
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Adaptation to high-altitude habitats in the Eastern honey

Adaptation to high-altitude habitats in the Eastern honey

The Eastern honey bee Apis cerana is of central importance for agriculture in Asia. It has adapted to a wide variety of environmental conditions across its native range in southern and eastern Asia, which includes high?altitude regions. Eastern honey bees inhabiting mountains differ morphologically from neighboring lowland populations, and may also exhibit differences in physiology and behavior. The genomes of 60 Eastern honey bees collected from high and low altitudes in Yunnan and Gansu provinces, China, were compared to infer their evolutionary history and to identify candidate genes that may underlie adaptation to high altitude. Using a combination of F_ST?based statistics, long?range haplotype tests, and population branch statistics, several regions of the genome were identified that appear to have been under positive selection. These candidate regions were strongly enriched for coding sequences and had high haplotype homozygosity and increased divergence specifically in highland bee populations, suggesting they have been subjected to recent selection in high altitude habitats. Candidate loci in these genomic regions included genes related to reproduction and feeding behavior in honey bees. Functional investigation of these candidate loci is necessary to fully understand the mechanisms of adaptation to high?altitude habitats in the Eastern honey bee. The results of this research will be very useful to monitor the populations of Asian bees and establish conservation priorities. Pollination services provided by bees are essential for food production throughout the world, but Asian bee populations in China have been declining since the early 20th century due to changes in agricultural practices and the introduction of non-native bees. Therefore, it is important to understand how populations of this species adapt to different environmental conditions such as altitude, as this can help improve conservation efforts and management. informacion[at] Montero-Mendieta et al (2018) The genomic basis of adaptation to high-altitude habitats in the Eastern honey bee (Apis cerana). Mol Ecol DOI 10.1111/mec.14986.