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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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The diet of the bottlenose dolphin described by stomach content and stable isotope analyses

The diet of the bottlenose dolphin described by stomach content and stable isotope analyses

The ecological role of species can vary among populations depending on local and regional differences in diet. This is particularly true for top predators such as the bottlenose dolphin, which exhibits a highly varied diet throughout its distribution range. Local dietary assessments are therefore critical to fully understand the role of this species within marine ecosystems, as well as its interaction with important ecosystem services such as fisheries. Here, stomach content analyses (SCA) and stable isotope analyses (SIA) were combined to describe bottlenose dolphins diet in the Gulf of Cadiz (North Atlantic Ocean). Prey items identified using SCA included European conger and European hake as the most important ingested prey. However, mass-balance isotopic mixing model (MixSIAR), using ?13C and ?15N, indicated that the assimilated diet consisted mainly on Sparidae species (e.g. seabream) and a mixture of other species including European hake, mackerels, European conger, red bandfish and European pilchard. These contrasting results highlight differences in the temporal and taxonomic resolution of each approach, but also point to potential differences between ingested (SCA) and assimilated (SIA) diets. Both approaches provide different insights, e.g. determination of consumed fish biomass for the management of fish stocks (SCA) or identification of important assimilated prey species to the consumer (SIA). informacion[at]ebd.csic.es: Giménez et al (2017) Diet of bottlenose dolphins (Tursiops truncatus) from the Gulf of Cadiz: Insights from stomach content and stable isotope analyses PLoS ONE https://doi.org/10.1371/journal.pone.0184673


http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0184673