Climate and mating phenology in ants

Authors: Helms Iv, Jackson

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/16/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: Organisms adjust the timing of life events, especially reproduction, in response to climate or other factors in their environment. But we know little about when and where mating occurs in ants, or how that might be changing with climate. To address this, we compiled a database of mating observations across all ant species known to occus in the continental U.S. We descibe when ant mating has occured in the past and how it changes with latitude and elevation, and we also test whether ant mating seasons occur earlier due to a warming climate. We found that about a fourth of the most commonly observered native species have advanced their mating season earlier in the year, consistent with predicted response sto warming temperatures.

Technical Abstract: Plastic or evolutionary shifts in phenology are key ways organisms respond to their environment. Reproductive timing incurs strong selective pressure because it directly impacts fitness. We lack comprehensive data on reproductive timing in one of the world’s most prominent insect groups—the ants. Ecological studies often focus on ant workers—the agents through which colonies interact with their environment—rather than on queens and males whose survival and reproduction constitute the direct fitness of ant lineages. We characterize the mating phenology of ants across the USA by synthesizing data from museum records dating back over a century. We characterize how ant mating seasons vary across time and space and test whether they have shifted in response to climate change. Average mating date across the ants increases by about 1 day per degree of latitude and per 100 meters elevation. Reproductive timing is over 1.5 times as variable at low latitudes than high, such that mating seasons can occur year-round in southern areas but occur mostly in late summer in the far north. Consistent with warming temperatures, a fourth of the native species analyzed have advanced their mating seasons by half a day per year in recent decades. No species delayed their mating seasons. Our results highlight the sensitivity of ants to climate change mediated by shifts in mating season, present a novel mechanism for climate-driven changes in ant community composition, and represent a first step toward a comprehensive theory of reproductive timing in ants.