Phylogenomic analyses re-examine the evolution of reinforcement and hypothesized hybrid speciation in Phlox wildflowers.

The tree of life is riddled with reticulate evolutionary histories, and some clades, such as the eastern standing Phlox, appear to be hotspots of hybridization. In this group, there are two cases of reinforcement and nine hypothesized hybrid species. Given their historical importance in our understanding of plant speciation, the relationships between these taxa and the role of hybridization in their diversification require genomic validation.

Characterizing each step of pollination in Phlox drummondii reveals that a single butterfly species predominates in the pollinator assemblage.

Premise: A central goal of pollination biology is to connect plants with the identity of their pollinator(s). While predictions based on floral syndrome traits are extremely useful, direct observation can reveal further details of a species' pollination biology. The wildflower Phlox drummondii has a floral syndrome consistent with pollination by Lepidoptera.

Flower orientation influences floral temperature, pollinator visits and plant fitness.

Effective insect pollination requires appropriate responses to internal and external environmental cues in both the plant and the pollinator. Helianthus annuus, a highly outcrossing species, is marked for its uniform eastward orientation of mature pseudanthia, or capitula. Here we investigate how this orientation affects floral microclimate and the consequent effects on plant and pollinator interactions and reproductive fitness.

Genomic analyses overturn two long-standing homoploid hybrid speciation hypotheses.

The importance of hybridization in generating biological diversity has been historically controversial. Previously, inference about hybridization was limited by dependence on morphological data; with the advent of the next-generation sequencing tools for nonmodel organisms, the evolutionary significance of hybridization is more evident. Here, we test classic hypotheses of hybrid origins of two species in the Phlox pilosa complex.

A Linkage-Based Genome Assembly for the Mosquito and Identification of Chromosomal Regions Affecting Diapause.

The Asian tiger mosquito, , is an invasive vector mosquito of substantial public health concern. The large genome size (~1.19-1.

Genomic Signatures of Reinforcement.

Reinforcement is the process by which selection against hybridization increases reproductive isolation between taxa. Much research has focused on demonstrating the existence of reinforcement, yet relatively little is known about the genetic basis of reinforcement or the evolutionary conditions under which reinforcement can occur. Inspired by reinforcement's characteristic phenotypic pattern of reproductive trait divergence in sympatry but not in allopatry, we discuss whether reinforcement also leaves a distinct genomic pattern.

Circadian regulation of sunflower heliotropism, floral orientation, and pollinator visits.

Young sunflower plants track the Sun from east to west during the day and then reorient during the night to face east in anticipation of dawn. In contrast, mature plants cease movement with their flower heads facing east. We show that circadian regulation of directional growth pathways accounts for both phenomena and leads to increased vegetative biomass and enhanced pollinator visits to flowers.

Genetic loci with parent-of-origin effects cause hybrid seed lethality in crosses between Mimulus species.

In flowering plants, F1 hybrid seed lethality is a common outcome of crosses between closely related diploid species, but the genetic basis of this early-acting and potentially widespread form of postzygotic reproductive isolation is largely unknown. We intercrossed two closely related species of monkeyflower, Mimulus guttatus and Mimulus tilingii, to characterize the mechanisms and strength of postzygotic reproductive isolation. Then, using a reciprocal backcross design, we performed high-resolution genetic mapping to determine the genetic architecture of hybrid seed lethality and directly test for loci with parent-of-origin effects.