Senior Honors Projects, 2020-current

The impact of water availability on male territoriality in the Damselfly Megalagrion calliphya

Erica Head


Previous studies indicate that the Pacific Islands are primarily feeling the impacts of environmental changes caused by climate change through more frequent and prolonged El Niño events that result in severe droughts (Loope & Giambelluca, 1998, Sun & Trenberth, 1998; Meehl, 1996). In particular, higher elevations in the Pacific Islands are more at risk of experiencing prolonged drought. The population of concern in this study is a high-elevation population of aquatic insects in Hawaii, Megalagrion calliphya damselflies. Megalagrion’s sensitivity to climate change may also serve as an indicator for other native species’ response to climate change, including behavioral responses. I investigated the behavioral responses of territorial male damselflies to water availability. I used data from a previous experiment on water availability that contained twelve artificial habitat sites, each consisting of four different sized pools, that were placed in a 200 meter transect at an altitude of 1200 meters. A drought was simulated by covering the largest of the pools at each site, which decreased water availability. I examined male damselfly presence and territory locations before and after the simulated drought. I found that male territorial behavior, including the size of the male territorial pool and whether the male left the study population, was not impacted by the simulated drought. Male behavior was also not correlated with previous duration of time spent at study site or the size of the territory. Male territory behavior is quite plastic, as males at larger pools were also seen at smaller pools, and vice-versa.