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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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Foxes, rabbits and nightjars interact on roads

Foxes, rabbits and nightjars interact on roads

Linear developments, such as roads, firebreaks, and railways, provide a stark juxtaposition of different habitats with contrasting associated predation risks, thus potentially influencing predator–prey interactions. However, empirical evidence is still very limited. The effect of fox abundance and that of their main prey, the European rabbit, on habitat selection by an alternative prey, the red-necked nightjar, was studied in a road network crossing the Doñana Natural Space. Nightjars generally forage on the same roads used by foxes to search for alternative prey when rabbits are scarce and, as a result, predation risk for nightjars may vary over time. Contrary to expectations, nightjars continued foraging on roads when foxes were most abundant, yet they behaved more cautiously. During risky periods, nightjars perched nearby tall roadside cover, which is known to functions as a protective barrier against fox attacks. Conversely, when predation risk decreased, nightjars shifted to safer microsites near short plants, further away from the roadside. This study shows how nightjar plasticity in microhabitat selection allows them to forage even in areas where predators are abundant, and highlights the important role that linear structures may play in interspecific interactions. informacion[at]ebd.csic.es: Camacho et el (2017) Nightjars, rabbits, and foxes interact on unpaved roads: spatial use of a secondary prey in a shared-predator system. Ecosphere DOI: 10.1002/ecs2.1611


http://onlinelibrary.wiley.com/doi/10.1002/ecs2.1611/full