Meeting Abstract
Splash-zone copepods (Tigriopus californicus) experience a variety of environmental fluctuations including changes in salinity, temperature, pH, and dissolved oxygen. We predicted that individuals acclimated to warmer temperatures would develop a thermal preference for cooler water, while also decreasing their activity level. Egg-mass-bearing females (n=48) were subjected to one of four temperature treatments for two weeks: 15°C, 19°C, 23°C and one treatment oscillating between 15-23°C each day. We assayed both activity patterns and thermal preference on each individual to examine the effects of fluctuating and constant temperature acclimation on behavior. We quantified activity of individual copepods in a novel, high-throughput microplate-based assay to look at the effects of acclimation to fluctuating and constant temperature on activity patterns during a controlled heat ramp (18-26°C). Results to date indicate that females acclimated to warmer temperatures have a thermal preference that averages ~4°C below their acclimation temperature, and those acclimated to a fluctuating thermal regime prefer temperatures close to the mean of the daily cycle. Meanwhile, copepods acclimated to 15°C preferred temperatures slightly above their acclimation temperature. Although there is only a weak effect of acute temperature change on activity levels during a heat ramp, there is evidence of decreased overall activity in copepods acclimated to higher temperatures. Our ultimate goal is to assess the ecological and evolutionary implications of environmental stress physiology and developmental plasticity of offspring in these dynamic and changing intertidal habitats.
