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Katleen Huyghe Annette Van Oystaeyen Frank Pasmans Zoran Tadić Bieke Vanhooydonck Raoul Van Damme 《Oecologia》2010,163(4):867-874
Permanent colour polymorphisms may be maintained by complex interactions between physiological traits (e.g. immunity) and
environmental pressures. In this study we investigate morph specific variation in parasite load and cellular immune response
(induced by a Phytohaemagglutinin, PHA injection) in a colour polymorphic population of the Dalmatian wall lizard (Podarcis melisellensis), where adult males have bright white, yellow or orange throats and ventral sides. Orange males have larger heads and can
bite harder than the others. To examine seasonal effects, analyses were performed at an early and late stage in the reproductive
season (May and September). Infection with mites and ticks did not differ among morphs, but was more severe at the end of
the reproductive season. Fewer orange individuals were infected with haemogregarines at the end of the season, but white males
were always more infected (higher number of haemogregarines in their blood) than other morphs. White and yellow males showed
an increased PHA response towards the end of the season, but PHA response decreased in the orange morph. Finally, across all
morphs, a relationship was found between ectoparasite load and PHA response. Our study provides indications of alternative
life-history strategies among colour morphs and evidence for an up-regulation of the immune function at the end of the reproductive
season. 相似文献
138.
Raoul Huys Laure Fernandez Reinoud J. Bootsma Viktor K. Jirsa 《Proceedings. Biological sciences / The Royal Society》2010,277(1685):1179-1184
It takes longer to accomplish difficult tasks than easy ones. In the context of motor behaviour, Fitts'' famous law states that the time needed to successfully execute an aiming movement increases linearly with task difficulty. While Fitts'' explicit formulation has met criticism, the relation between task difficulty and movement time is invariantly portrayed as continuous. Here, we demonstrate that Fitts'' law is discontinuous in reciprocal aiming owing to a transition in operative motor control mechanisms with increasing task difficulty. In particular, rhythmic movements are implemented in easy tasks and discrete movements in difficult ones. How movement time increases with task difficulty differs in both movement types. It appears, therefore, that the human nervous system abruptly engages a different control mechanism when task difficulty increases. 相似文献
139.
Limnology - Aquatic macrophytes play an important role in structuring biotic communities. A comparative study of macroinvertebrate community structures associated with Salvinia auriculata Aublet... 相似文献
140.