Inbreeding depression, the reduced fitness of the offspring of related individuals, can affect males and females differently. Although a comprehensive theoretical framework describing the causes of sex-specific inbreeding depression is lacking, empirical evidence suggests that often one sex tends to be more vulnerable than the other. However, the generality, direction, and degree of sex-specific difference in inbreeding depression remains enigmatic as studies on this topic have reported conflicting results.
View Article and Find Full Text PDFAnimals are usually expected to avoid mating with relatives (kin avoidance) as incestuous mating can lead to the expression of inbreeding depression. Yet, theoretical models predict that unbiased mating with regards to kinship should be common, and that under some conditions, the inclusive fitness benefits associated with inbreeding can even lead to a preference for mating with kin. This mismatch between empirical and theoretical expectations generates uncertainty as to the prevalence of inbreeding avoidance in animals.
View Article and Find Full Text PDFPhilos Trans R Soc Lond B Biol Sci
December 2020
Females of many species mate with multiple males, thereby inciting competition among ejaculates from rival males for fertilization. In response to increasing sperm competition, males are predicted to enhance their investment in sperm production. This prediction is so widespread that testes size (correcting for body size) is commonly used as a proxy of sperm competition, even in the absence of any other information about a species' reproductive behaviour.
View Article and Find Full Text PDFMale mate choice occurs in a wide range of species, and males can increase their reproductive success by distinguishing between females based on their fecundity (e.g., large body size) or their expected sperm competition risk (e.
View Article and Find Full Text PDFInbreeding negatively affects various life-history traits, with inbred individuals typically having lower fitness than outbred individuals (= inbreeding depression). Inbreeding depression is often emphasized under environmental stress, but the underlying mechanisms and potential long-lasting consequences of such inbreeding-environment interactions remain poorly understood. Here, we hypothesize that inbreeding-environment interactions that occur early in life have long-term physiological effects, in particular on the adult oxidative balance.
View Article and Find Full Text PDFInbreeding is a central topic in evolutionary biology and ecology and is of major concern for the conservation of endangered species. Yet, it remains challenging to comprehend the fitness consequences of inbreeding, because studies typically focus only on short-term effects on inbreeding in the offspring (e.g.
View Article and Find Full Text PDFInbreeding depression plays a significant role in evolutionary biology and ecology. However, we lack a clear understanding of the fitness consequences of inbreeding depression. Studies often focus on short-term effects of inbreeding in juvenile offspring, whereas inbreeding depression in adult traits and the interplay between inbreeding depression and age are rarely addressed.
View Article and Find Full Text PDFThe early developmental trajectory is affected by genetic and environmental factors that co-depend and interact often in a complex way. In order to distinguish their respective roles, we used canaries () of different genetic backgrounds (inbred and outbred birds). An artificial size hierarchy was created to provoke within-nest competition, manipulating postnatal conditions.
View Article and Find Full Text PDFThe expression of bird song is expected to signal male quality to females. 'Quality' is determined by genetic and environmental factors, but, surprisingly, there is very limited evidence if and how genetic aspects of male quality are reflected in song. Here, we manipulated the genetic make-up of canaries (Serinus canaria) via inbreeding, and studied its effects upon song output, complexity, phonetics and, for the first time, song learning.
View Article and Find Full Text PDFUnderstanding how the intensity of inbreeding depression is influenced by stressful environmental conditions is an important area of enquiry in various fields of biology. In birds, environmental stress during early development is often related to hatching asynchrony; differences in age, and thus size, impose a gradient in conditions ranging from benign (first hatched chick) to harsh (last hatched chick). Here, we compared the effect of hatching order on growth rate in inbred (parents are full siblings) and outbred (parents are unrelated) canary chicks (Serinus canaria).
View Article and Find Full Text PDFCommunication is important in social species, and may occur with the use of visual, olfactory or auditory signals. However, visual communication may be hampered in species that are arboreal have elaborate facial coloring and live in small groups. The common marmoset fits these criteria and may have limited visual communication.
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