Variation in temperature can affect the expression of a variety of important fitness‐related behaviours, including those involved with mate attraction and selection, with consequences for the coordination of mating across variable environments. We examined how temperature influences the expression of male mating signals and female mate preferences—as well as the relationship between how male signals and female mate preferences change across temperatures (signal–preference temperature coupling)—in Enchenopa binotata treehoppers. These small plant‐feeding insects communicate using plantborne vibrations, and our field surveys indicate they experience significant natural variation in temperature during the mating season. We tested for signal–preference temperature coupling in four populations of E. binotata by manipulating temperature in a controlled laboratory environment. We measured the frequency of male signals—the trait for which females show strongest preference—and female peak preference—the signal frequency most preferred by females—across a range of biologically relevant temperatures (18°C–36°C). We found a strong effect of temperature on both male signals and female preferences, which generated signal–preference temperature coupling within each population. Even in a population in which male signals mismatched female preferences, the temperature coupling reinforces predicted directional selection across all temperatures. Additionally, we found similar thermal sensitivity in signals and preferences across populations even though populations varied in the mean frequency of male signals and female peak preference. Together, these results suggest that temperature variation should not affect the action of sexual selection via female choice, but rather should reinforce stabilizing selection in populations with signal–preference matches, and directional selection in those with signal–preference mismatches. Finally, we do not predict that thermal variation will disrupt the coordination of mating in this species by generating signal–preference mismatches at thermal extremes.

Temperature influences the expression of a wide range of behavioral traits in ectotherms, including many involved in the initiation of pair formation and mating. Although opportunities to mate are thought to be greatest when male and female activity overlap, sex‐specific behaviors and physiology could result in mismatched thermal optima for male and female courtship. Here, we investigate how conflicts in the thermal sensitivity of male and female courtship activity affect patterns of mating across temperatures in Enchenopa binotata treehoppers (Hemiptera: Membracidae). These plant‐feeding insects coordinate mating with plant‐borne vibrational signals exchanged in male–female duets prior to pair formation. We manipulated temperature across an ecologically relevant range (18–36ºC) and tested the likelihood of individual male and female E. binotata to engage in courtship activity using vibrational playbacks. We then staged male–female mating interactions across the same temperature range and quantified the thermal sensitivity of mating‐related behaviors across stages of mating. Specifically, we measured the timing of duetting, the likelihood for key pre‐copulatory behaviors to occur, whether the pair mated, and copulation duration. We found sex‐specific thermal sensitivity in courtship activity: Males showed a clear peak of activity at intermediate temperatures (27–30ºC), while females showed highest activity at the hotter thermal extreme. Mating rates, courtship duets, and copulatory attempts were less likely to occur at thermal extremes. Also, duetting occurred earlier and copulation was shortest at higher temperatures. Overall, our data suggest that sexes differ in how temperature affects mating‐related activity and some processes involved in mate coordination may be more sensitive than others across variable thermal environments.

We compared pollination and seed set of bicolor and concolor morphs in self-incompatible, Viola pedata over two seasons in two populations of unequal sizes.  One population grew on a wooded slope (CR) and the second on an exposed glade (SNR).  Both were burned in 2014. The number of flowers produced by concolor plants at SNR was higher in 2014 while the number of flowering bicolors increased at CR in 2015. Petal temperatures, regardless of site, showed that dark purple, posterior petals of bicolors were consistently warmer than their own mauve-lilac, anterior (lip) petals and the all mauve petals of concolors. Major pollen vectors were female bees (Andrenidae, Apidae and Halictidae) but polylectic, Andrena carlinii dominated both sites.  Bees foraged on flowers upside down or right side up but neither mode correlated with either morph. Bees foraged preferentially on concolor at both sites.  Pistils containing pollen tubes were higher in concolor pistils at both sites with a marginally greater number of  tubes penetrating concolor ovules regardless of site or year.  While both populations produced more seeds in 2014 SNR plants always produced more seeds than CR plants.  The increasing numbers of bicolor plants at CR in 2015 suggested that bicolors may equal or outnumber concolors when dark petals offer additional warmth to ectothermic pollinators in a shady (cooler) forest vs. an open, sunny glade. Subtle environmental factors may give a floral trait a selective advantage influencing fitness in an unbalanced polymorphism persisting in localized populations.