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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]ebd.csic.es: Álvarez et al (2020) Breeding consequences for a songbird nesting in Argentine ant' invaded land. Biol Invasions https://doi.org/10.1007/s10530-020-02297-3


https://link.springer.com/article/10.1007/s10530-020-02297-3
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Birds present worse body conditions in more urbanized areas

Birds present worse body conditions in more urbanized areas

Human landscape transformation, especially urbanization, strongly affects ecosystems worldwide. Both urban stressors and parasites have negative effects on organism health, however the potential synergy between those factors has been poorly investigated. The body condition (i.e. body mass after controlling for wing chord) of 2043 house sparrows (Passer domesticus; adults and yearlings) captured in 45 localities along an urbanization gradient in relation to Plasmodium, Haemoproteus and Leucocytozoon infection status was analysed. Body condition was negatively related to urbanization level and to urbanized land coverage but only in yearling birds from urban habitats. In addition, bird body condition tended to increase in rural habitats, significantly in the case of yearlings. Infected individuals by Plasmodium or Haemoproteus had higher body condition than un-infected birds, but this pattern could be due to a selective disappearance of infected individuals with lower body condition as suggested by the reduced variance in body condition in infected birds in urban habitats. These results provide support for a negative impact of urbanization on bird body condition, while Plasmodium and Haemoproteus may exert selection against individuals with lower body condition living in urban habitats, especially during earlier life stages, underlining the synergistic effects that urbanization and parasites may have on wild birds. informacion[at]ebd.csic.es: Jiménez-Peñuela et al (2018) Urbanization and blood parasite infections affect the body condition of wild birds. Sci Total Environ Doi 10.1016/j.scitotenv.2018.10.203


http://www.sciencedirect.com/science/article/pii/S0048969718340944