@article {8807, title = {Male spotless starlings adjust feeding effort based on egg spots revealing ectoparasite load}, journal = {Animal Behaviour}, volume = {78}, number = {4}, year = {2009}, month = {October}, pages = {993-999}, type = {Article}, abstract = {Parents may vary their parental behaviour and investment in reproduction in response to parasiteinduced changes in the fitness prospects of their offspring. Thus, parents may use the physical condition of their offspring, or any other trait related to parasite load, to adjust parental effort. The immaculate eggs of the spotless starling, Sturnus unicolor, often become densely spotted owing to the activity of the ectoparasite carnid fly Carnus hemapterus. Spot density anticipates the intensity of fly infestation suffered by nestlings and, therefore, may serve as a cue for parents to adjust reproductive investment. By cleaning spots produced by C. hemapterus on eggs of spotless starlings, we manipulated the parasite{\textquoteright}s traces revealing its presence in broods of starlings, without modifying the level of infestation, to test whether parents use these signals to adjust reproductive effort. We found support for the hypothetical negative effect of Carnus flies since nestlings raised in nests with a higher fly load had lower body mass. The experimental egg cleaning during incubation did not change the intensity of carnid fly infestation during nestling development. However, it had a significant positive influence on paternal but not maternal effort. Our experimental results support the idea that spotless starling males adjust their effort in response to their perception of the fitness prospects of their nestlings as indirectly estimated by traces of parasites on the eggshells. As far as we know, this is the first evidence of the use of parasite traces to infer risk of parasitic infestation by animal hosts. [copyright] 2009 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.}, keywords = {Carnidae, Carnus hemapterus, on Sturnus unicolor}, isbn = {0003-3472}, url = {://ZOOREC:ZOOR14602009277 }, author = {Jesus M Aviles and Perez-Contreras, Tomas and Navarro, Carlos and Juan J. Soler} } @article {3602, title = {Habitat-specific effects of a food supplementation experiment on immunocompetence in Eurasian magpie Pica pica nestlings}, journal = {Ibis}, volume = {149}, number = {4}, year = {2007}, month = {October}, pages = {763-773}, type = {Article}, abstract = {Parasite pressure and nutrition are two of the most important factors affecting the trade-off between nestling growth and immune development. During development, energy and nutrients are often limited, and nestlings should only dedicate differentially more valuable resources to their immune system when the associated benefits are high (i.e. in situations of an increased risk of parasitism). In this study, we manipulated nutritional condition of Eurasian Magpie Pica pica nestlings by providing a food supplement. Additionally, the study area was subdivided into two categories of habitat (irrigated and arid) based on the presence of irrigation canals. Nestling diet composition was more varied in the irrigated compared with in the arid habitat. In addition, nestlings of the irrigated habitat showed a significantly higher infestation of both ectoparasites and blood parasites and a significantly higher cell-mediated immunity, but lower tarsus length compared with nestlings of the arid habitat. Food supplementation to nestlings did not affect tarsus length, but increased nestling cell-mediated immunity in the arid habitat only. Based on the recent demonstrated trade-off between growth and immunocompetence in nestlings, we suggest that differences between habitats in nestling diet and parasite prevalence may have caused different priority rules in the allocation of resources between both fitness traits. }, isbn = {0019-1019}, url = {://ZOOREC:ZOOR14406036320 }, author = {de Neve, L. and Juan J. Soler and Ruiz-Rodriguez, Magdalena and Martin-Galvez, David and Perez-Contreras, Tomas and Soler, Manuel} } @article {1783, title = {Relative importance of factors affecting nestling immune response differs between junior and senior nestlings within broods of hoopoes Upupa epops}, journal = {Journal of Avian Biology}, volume = {37}, number = {5}, year = {2006}, month = {September}, pages = {467-476}, abstract = {Animals should invest in the immune system to protect themselves from parasites, but the cost of immune responses may limit investment depending on resource availability. In birds\&$\#$39; broods, senior and junior chicks in size hierarchies face different rearing conditions, and thus we predicted that factors affecting immune response should differ between them. In asynchronously hatched hoopoe Upupa epops broods, we found that the immune response of senior nestlings was not related to their body condition, but positively related to risk of parasitism (which was indirectly estimated by laying date). This suggests that their immunocompetence is not limited by access to resources, and they can differentially invest in immune response with increasing risk of parasitism. On the other hand, immune response of junior nestlings was related to their body condition, but secondarily also to risk of parasitism. Our results agree with previous studies that have found significant influence of nutritional status and risk of parasitism on nestlings immune defence, but show that the effects of these environmental factors on nestling immunocompetence differ between nestlings occupying high and low rank positions in size hierarchies. The possible influence of maternal effects on the results found is also discussed. }, keywords = {Carnidae, Carnus, Carnus hemapterus, Spain}, isbn = {0908-8857}, author = {Martin-Vivaldi, Manuel and Ruiz-Rodriguez, Magdalena and Mendez, Maria and Juan J. Soler} }