The adaptedness of the floral phenotype in a relict endemic, hawkmoth-pollinated violet. 2. Patterns of variation among disjunct populations

Abstract

This study examines patterns of variation in quantitative floral traits among 18 disjunct populations of Viola cazorlensis (Violaceae), a relict endemic violet of south-eastern Spain. At all sites, the species is almost exclusively pollinated by a single species of day-flying hawkmoth. Differences between populations were significant for all traits examined, and population means exhibit a broad range of variation. When all characters are considered together, each population displays a unique combination of characters. Despite interpopulation differences in character means, local populations retain most of the variability of the entire species. Floral traits d o not vary in unison among flowers, and at least four different subsets of independently varying traits are identifiable. Floral similarity between populations of V. cazorlensis was largely unrelated to geographic proximity, as revealed by analyses at both large and small geographic scales. The geographic pattern of floral variation among populations represents a random patchwork, with unique combinations of character means occurring randomly across the study region. Marked population differences in quantitative floral traits in spite of spatial constancy in the identity of pollinators, a disintegrated floral phenotype, and prevailingly random geographic variation among populations, suggest low adaptedness of the floral phenotype of V. cazorlensir to its current hawkmoth pollinators.

Comparative floral and vegetative differentiation between two European Aquilegia taxa along a narrow contact zone

“…Multivariate vegetative, but not floral, similarity between populations could be predicted from geographical distance, indicating that populations that are geographically closer tend to be more similar in vegetative traits, but not in their floral characteristics, than those that are more distant. This pattern of distance-independent floral differentiation among populations is similar to the ''random patchwork'' pattern of floral morphology described by Herrera (1990) for Viola cazorlensis, another narrowly endemic species with isolated populations distributed over the study region.…”

“…In contrast, there have been relatively few investigations focusing on the connections between microand macroevolutionary patterns of floral variation (Miller 1981, Barrett 1995, Johnson 1997, and on intraspecific floral variation and its relationship to evolutionary divergence in pollinators (see however e.g. Herrera 1990, Robertson and Wyatt 1990, Arroyo and Dafni 1995, Boyd 2002, Herrera et al 2002, SilvaMontellano and Eguiarte 2003.…”

Variação na arquitetura floral e sucesso reprodutivo de duas espécies de Helicteres (Malvaceae), na região sudoeste de Mato Grosso

“…A evolução de plantas ornitófi las e outros polinizadores vertebrados, têm se apresentado bastante próximas (Muchhala 2007) e é razoável supor que a variação na arquitetura fl oral passa pela variação no sucesso reprodutivo das plantas, principalmente quando as características envolvidas afetam a atração de polinizadores ou transferência de pólen (Herrera 1990).…”

Reproductive success and variation in floral traits in the Iberian Peninsula endemic white campion Silene marizii (Caryophyllaceae)

“…Variable morphological traits that have no effect on reproductive success are unlikely to lead to evolutionary change (Herrera 1990). In many plant species, the size and number of reproductive structures and the components of female reproductive success show marked among-flower withininflorescence variation (e.g.…”

“…Over the last few decades, different authors have followed various approaches to study the variation in floral morphology and its effect on reproductive success (Schlichting 1986;Herrera 1990;Wolfe 1993;Johnson et al 1995;Diggle 1995;García-Cruz & Sosa 2007).…”