Theoretical models indicate that speciation, especially when the scope for gene flow is great
(eg, sympatric speciation), is most likely when strong performance trade-offs coincide with …

Efforts to understand the process of speciation have been central to the research of
biologists since the origin of evolutionary biology as a discipline. While it is well established …

The Mediterranean Basin represents a Global Biodiversity Hotspot where many organisms
show high inter-and intraspecific differentiation. Extant phylogeographic patterns of …

Crossbills (Loxia spp.) provide a classical avian model of ecological specialization on food
resources. Previous studies have suggested that morphometric, genetic and vocal …

Bird-mediated seed dispersal is crucial for the regeneration and viability of ecosystems,
often resulting in complex mutualistic species networks. Yet, how this mutualism drives the …

The process of speciation remains poorly understood and hence definitions of species
continue to be a focus of sharp debate. A key unresolved issue in speciation debates is …

Carotenoid-based ornamentation can vary greatly among individual birds of the same
population. This variability might consider the timing and duration of moult. Crossbills (genus …

Carotenoid-based ornaments are often considered reliable (honest) individual condition
signals because their expression implies physiological costs unaffordable for low-quality …

Mediterranean Crossbills are as much differentiated as L. scotica and L. pytyopsittacus.
They are sedentary, linked to pine trees and have evolved a thicker bill to extract the seeds …

Species delineation has a long and contentious history, yet most agree that sympatric
populations exhibiting high levels of reproductive isolation and evolving independently are …