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Ploquin E.F.,University of Oviedo | Ploquin E.F.,Research Unit of Biodiversity UMIB | Herrera J.M.,University of Oviedo | Herrera J.M.,Research Unit of Biodiversity UMIB | And 3 more authors.
Oecologia | Year: 2013

Widespread alterations in species distribution and abundance as a result of global environmental change include upwards and polewards shifts driven by local extinctions in the south or at lower elevations and colonizations of newly available habitat elements in the north or at higher elevations. Although cumulative changes on patterns of community composition are also expected, studies following a community-level approach are still scarce. Here, we estimate changes in abundance and distribution of bumblebee (Bombus spp.) species over two decades along an elevational gradient to test whether these changes entailed concomitant alterations on patterns of community composition. Bumblebee species showed an overall trend to shift uphill their upper- or lower-elevational boundaries, resulting in narrower elevational ranges from one period to another, coincident with a regional warming of ca. 0.9 °C. Changes in elevational ranges were, however, mainly related to retractions of the lower limit of species distribution, rather than to variations in their upper elevational limit. Species turnover was associated with colonization and extinction events and also with variability in the relative abundance of short-, medium- and long-tongued species along the elevational gradient. Extinctions were especially relevant at medium elevations, while only communities at higher elevations had a positive net outcome between colonization and extinction events. The combination of these effects resulted in the homogenization of bumblebee assemblages, especially between medium and upper elevations. The changes reported in our study strongly match with predictions of global change driving elevational shifts in species distribution and provide the first evidence of elevational changes in bumblebees at both species and community level. © 2013 Springer-Verlag Berlin Heidelberg.

Bolopo D.,University of Valladolid | Canestrari D.,University of Oviedo | Canestrari D.,Research Unit of Biodiversity UMIB | Roldan M.,University of Granada | And 3 more authors.
Behavioral Ecology and Sociobiology | Year: 2015

In nests of birds parasitized by a larger non-evicting brood parasite, host chicks typically are at disadvantage in competing for food and often starve. However, when host chicks are larger, they may benefit from the presence of the parasite, which contributes to the net brood begging signal but cannot monopolize the food brought to the nest. Here, we show that, despite a higher begging intensity, great spotted cuckoos (Clamator glandarius) did not outcompete larger size carrion crow (Corvus corone corone) nestlings. Furthermore, cuckoos’ exaggerated begging allowed crow nest mates to decrease their begging intensity without negative consequences on food intake. Assuming an energetic cost to chicks of begging intensely, our results suggest that crow chicks sharing the nest with a cuckoo may obtain an advantage that should be weighed against the loss of indirect fitness due to parasitism. © 2015, Springer-Verlag Berlin Heidelberg.

Roder G.,University of Neuchatel | Canestrari D.,University of Oviedo | Canestrari D.,Research Unit of Biodiversity UMIB | Bolopo D.,University of Valladolid | And 5 more authors.
Journal of Chemical Ecology | Year: 2014

The great spotted cuckoo (Clamator glandarius) is an important brood parasite of carrion crows (Corvus corone corone) in northern Spain. We recently found that, unlike what is commonly known for cuckoo-host interactions, the great spotted cuckoo has no negative impact on average crow fitness in this region. The explanation for this surprising effect is a repulsive secretion that the cuckoo chicks produce when they are harassed and that may protect the brood against predation. Here, we provide details on the chemical composition of the cuckoo secretion, as well as conclusive evidence that the dominating volatile chemicals in the secretion are highly repellent to model species representative of common predators of the crows. These results support the notion that, in this particular system, the production of a repulsive secretion by the cuckoo chicks has turned a normally parasitic interaction into a mutualistic one. © 2014 Springer Science+Business Media New York.

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