Publications by authors named "Johan R Vikan"
Article Synopsis
- Natural selection may favor maternal control of offspring sex ratios based on the ability to invest in offspring, especially among generalist parasites like the common cuckoo.
- The study investigated the relationship between host-specific sex allocation in cuckoos, but found no significant correlation between host race, host quality, and sex ratio across multiple populations.
- Results indicate that common cuckoos do not exhibit a sex-ratio bias linked to host race or maternal quality, suggesting broader implications regarding gene flow and host adaptations.
Article Synopsis
- - The study investigates how environmental variations affect the interactions between parasitic common cuckoos and their reed warbler hosts across different European populations, focusing on traits like egg matching and host defenses.
- - Researchers found that differences in the ability of warbler hosts to reject cuckoo eggs (defenses) correlated with how well cuckoo eggs matched the warblers' eggs, varying across populations.
- - Although climatic conditions influenced the traits of both cuckoos and hosts, the study suggests that the defenses of the hosts play a more significant role in driving evolutionary changes in cuckoo egg mimicry.
Background: Antagonistic species often interact via matching of phenotypes, and interactions between brood parasitic common cuckoos (Cuculus canorus) and their hosts constitute classic examples. The outcome of a parasitic event is often determined by the match between host and cuckoo eggs, giving rise to potentially strong associations between fitness and egg phenotype. Yet, empirical efforts aiming to document and understand the resulting evolutionary outcomes are in short supply.
View Article and Find Full Text PDFArticle Synopsis
- Generalist parasites like the common cuckoo can evolve host-specific races that adapt to particular host species, often stemming from isolated populations that develop unique traits.
- In areas where multiple host races exist, there is a concern that gene flow might disrupt these specific adaptations, although in the case of the cuckoo, it's been thought that only females drive these adaptations through their W-chromosome.
- This study found significant genetic differences in both male and female cuckoos, suggesting that males also play a role in the evolution of these host races, indicating that important genes related to egg traits may be located on regular chromosomes instead of just the W-chromosome.