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Parental Ability (parental + ability)
Selected AbstractsThe role of melanin- and carotenoid-based plumage coloration in nest defence in the Great TitETHOLOGY, Issue 7 2007Javier Quesada Although plumage coloration is recognized to convey valuable information about the bearer's parental abilities, few studies have explored the relationship between coloration and nest defence. In this study in Great Tit Parus major, we analysed the relationship between nest defence and melanin- as well as carotenoid-based plumage coloration, after controlling for ecological variables known to influence nest defence. A principal components analysis was applied to classify birds according to how vigorously they defended the nest, and the intensity of nest defence was tested against plumage coloration. Males with a large black tie defended their nests more vigorously, but no such effect was found for yellow breast coloration. This suggests that melanin-based coloration in the Great Tit is associated with aggression, including both dominance-aggression and nest defence, whereas carotenoid-based coloration is not. The challenge in future studies will be to demonstrate whether females use this trait as an ornament to assess male quality and whether they trade off between the different ornaments a male may exhibit. [source] Age-dependent reproductive costs and the role of breeding skills in the Collared flycatcherACTA ZOOLOGICA, Issue 2 2007Joanna Sendecka Abstract This study addressed whether there are any age-related differences in reproductive costs. Of especial interest was whether young individuals increased their reproductive effort, and thereby their reproductive cost, as much as older birds when brood size was enlarged. To address these questions, a brood-size manipulation experiment with reciprocal cross-fostering of nestlings of young and middle-aged female Collared flycatchers, Ficedula albicollis, was performed on the Swedish island of Gotland. Nestlings' body mass, tarsus length and survival were recorded to estimate the parental ability and parental effort of the experimental female birds. Female survival and clutch size were recorded in the following years to estimate reproductive costs. We found that middle-aged female flycatchers coped better with enlarged broods than younger females or invested more in reproduction. In the following year, young female birds that had raised enlarged broods laid smaller clutches than the females from all the other experimental groups. This result shows that the young female birds pay higher reproductive costs than the middle-aged females. Both young and middle-aged female flycatchers seemed to increase their reproductive effort when brood size was increased. However, such an increase resulted in higher reproductive costs for the young females. The difference in reproductive costs between birds of different ages is most likely a result of insufficient breeding skills of the young individuals. [source] Parental Effort in Relation to Structural Plumage Coloration in the Mountain Bluebird (Sialia currucoides)ETHOLOGY, Issue 9 2007Susan L. Balenger Indicator models of sexual selection suggest that costly ornaments signal reliable information regarding an individual's quality to potential mates. In species that produce altricial offspring, the amount of parental care provided by both males and females can impact reproductive success. The Good Parent Hypothesis proposes that ornamentation in biparental species can act as an honest signal of parental ability to potential mates. We tested this hypothesis using the mountain bluebird (Sialia currucoides), a sexually dichromatic, socially monogamous species in which both sexes have structurally based ornamental plumage coloration. A male's plumage color predicted neither the rate at which it provisioned nestlings nor brood growth rate. The same was true for females. We also found no indication of assortative mating by color or body condition. Feeding rates within pairs were positively correlated, which we suggest may be due to pairs responding similarly to the perceived needs of nestlings or to local area prey availability. In sum, our results do not support the Good Parent Hypothesis as an explanation for the evolution of ornamental plumage color in mountain bluebirds. We suggest alternative hypotheses for the evolution of ornamental plumage color in this species. [source] When fathers make the difference: efficacy of male sexually selected antimicrobial glands in enhancing fish hatching successFUNCTIONAL ECOLOGY, Issue 1 2010Matteo Pizzolon Summary 1.,Egg and offspring resistance to pathogens is a major determinant of survival and has been mainly ascribed to maternal factors. However, paternal production of antimicrobials was recently suggested to increase offspring survival in species where males perform egg care. 2.,In the peacock blenny, Salaria pavo, a demersal spawning species where males exhibit a pair of anal glands producing lysozyme-like compounds, we tested the antimicrobial activity and the egg protection efficacy of these glands. The anal gland secretion (AGS) has an inhibitory effect on the growth of both Gram-negative and Gram-positive bacteria, including those causing the most severe fish diseases in marine culture. The egg clutches cared for by males deprived of anal glands have a significantly lower survival rate than those cared for by sham-operated males and non-viable eggs showed clear signs of bacterial infection. 3.,Anal gland secretion production and its protein content are proportional to gland size. In species where male parental care plays a crucial role in offspring survival, females are expected to assess mates selecting those traits that are reliably associated with parental ability. Hence, we experimentally challenged females with dummy males differing in anal gland size. Females definitely preferred dummy males with larger anal glands, suggesting that their choice is driven by the pursuit of direct fecundity benefits. 4.,These findings indicate that antimicrobial production is a crucial component of male parental care. The contribution of antimicrobials to male performance as fathers suggests that the development of traits devoted to this function may influence male attractiveness and be sexually selected. [source] | ||||||||||