Elevated temperature increases reproductive investment in less preferred mates in the invasive European corn borer moth

Abstract

Rapidly changing environments may weaken sexual selection and lead to indiscriminate mating by interfering with the reception of mating signals or by increasing the costs associated with mate choice. If temperature alters sexual selection, it may impact population response and adaptation to climate change. Here, we examine how differences in temperature of the mating environment influence reproductive investment in the European corn borer moth (Ostrinia nubilalis). Mate preference in this species is known to be related to pheromone usage, with assortative mating occurring between genetically distinct E and Z strains that differ in the composition of female and male pheromones. We compared egg production within and between corn borer lines derived from four different populations that vary in pheromone composition and other traits. Pairs of adults were placed in a mating environment that matched the pupal environment (ambient temperature) or at elevated temperature (5°C above the pupal environment). At ambient temperature, we found that within‐line pairs produced eggs sooner and produced more egg clusters than between‐line pairs. However, at elevated temperature, between‐line pairs produced the same number of egg clusters as within‐line pairs. These results suggest that elevated temperature increased investment in matings with typically less preferred, between‐line mates. This increased investment could result in changes in gene flow among corn borer populations in warming environments.

The role of sexual isolation during rapid ecological divergence: Evidence for a new dimension of isolation in Rhagoletis pomonella

“…Though warmer rearing temperatures did not change the overall strength of sexual isolation between populations, asymmetric contributions to total sexual isolation under warming conditions could facilitate asymmetric gene flow. While the causal mechanisms are unknown, a study in European corn borer moths similarly found a higher potential for gene flow under warmer rearing temperatures (Enos & Kozak, 2021). Sexual isolation may be particularly sensitive to environmental changes when differences in mating preferences and traits evolved due to environmental differences (Fisher et al, 2006; Lackey & Boughman, 2013; Seehausen et al, 1997; Ward & Blum, 2012).…”

“…Moreover, such changes could potentially increase, decrease, or have no effect on gene flow between populations (García‐Roa et al, 2020; Larson et al, 2019). However, two recent examples in insects found warmer temperatures caused higher mating rates between populations (Enos & Kozak, 2021; Kindle et al, 2006).…”

Effect of short-term exposure to high temperatures on the reproductive behavior and physiological enzyme activities in the fruit fly Zeugodacus tau (Walker)

“…High-temperature and low-temperature stress irreversibly damages the function and structure of the reproductive system, thus, affecting the mating behavior of ectotherms (Singh et al, 2015;Enos and Kozak, 2021). High and low temperatures affect the mating behavior of fruit flies, including the mating-related traits of mating latency, duration of copulation, mating frequency, the number of progeny produced, etc.…”

Temperature impacts how sugar resources alter reproductive investment in the European corn borer moth

“…Previous work has found that when E and Z strain individuals are given the opportunity to mate with access only to water at standard temperatures (22–24 °C), females are more likely to mate with males of their own strain and females lay more egg clusters with preferred males (Liebherr and Roelofs 1975, Pélozuelo et al 2007, Dopman et al 2010, Enos and Kozak 2021). When exposed to elevated temperatures (above 27 °C) with access only to water, previous work found that mating pairs show patterns consistent with terminal investment of resources to reproduction: females lay more eggs earlier in life independent of the strain of the mate (Lee and Spence 1987, Enos and Kozak 2021). Building on this prior work, we provided adult corn borer moths access to supplemental sugar solutions during mating, at both ambient (23 °C) and elevated (28 °C) temperature.…”