Local conditions have greater influence than provenance on sugar maple (Acer saccharum Marsh.) frost hardiness at its northern range limit.

In temperate and boreal ecosystems, trees undergo dormancy to avoid cold temperatures during the unfavorable season. This phase includes changes in frost hardiness, which is minimal during the growing season and reaches its maximum in winter. Quantifying frost hardiness is important to assess the frost risk and shifts of species distribution under a changing climate.

The genetic basis of floral mechanical isolation between two hummingbird-pollinated Neotropical understorey herbs.

Floral divergence can contribute to reproductive isolation among plant lineages, and thus provides an opportunity to study the genetics of speciation, including the number, effect size, mode of action and interactions of quantitative trait loci (QTL). Moreover, flowers represent suites of functionally interrelated traits, but it is unclear to what extent the phenotypic integration of the flower is underlain by a shared genetic architecture, which could facilitate or constrain correlated evolution of floral traits. Here, we examine the genetic architecture of floral morphological traits involved in an evolutionary switch from bill to forehead pollen placement between two species of hummingbird-pollinated Neotropical understorey herbs that are reproductively isolated by these floral differences.

Correction: Genetic introgression among differentiated clades is lower among clades exhibiting different parity modes.

The original version of this Article contained an error in the spelling of the author Y. Surget-Groba, which was incorrectly given as J. Surget-Groba.

Genetic introgression among differentiated clades is lower among clades exhibiting different parity modes.

Mechanisms leading to sympatric speciation are diverse and may build up reproductive isolation. Reproductive isolation among differentiated clades may exist due to genetic incompatibilities, sexual selection, differences in parity mode, reduced post-zygotic survival or reproductive success of hybrids. Here, we test whether differences in parity mode lead to reproductive isolation by investigating introgression in Zootoca vivipara, a lizard species exhibiting oviparous and viviparous reproduction.