Motion‐triggered laser photography reveals fine‐scale activity patterns for burrowing crayfish

Abstract

Abstract Burrowing crayfish represent 15% of total crayfish species and 32% of imperilled species. Few life history studies exist for these species and more information is needed regarding their ecology, population status, distribution, and biogeography for effective conservation efforts. Challenges to gaining such information include sampling difficulty and small sample sizes. Collection efforts may be more efficient if activity patterns can be identified for species of interest. The goal of our study was to assess specific environmental indicators of burrowing crayfish activity patterns. We evaluated activity patterns of two primary burrowing crayfish species, Lacunicambarus erythrodactylus (Simon & Morris, Proc. Biol. Soc. Wash., 127, 2014, 572) and Procambarus holifieldi (Schuster, Taylor, & Adams, Zootaxa, 4021, 2015, 1) using laser‐triggered digital photography for one‐year periods in the Bogue Chitto Creek floodplain, Dallas County, Alabama, U.S.A. We predicted that activity would be related to time of day, season, groundwater depth, and precipitation. Activity by L. erythrodactylus covaried significantly with time of day, daylength, groundwater temperature, and relative air temperature, while activity by P. holifieldi covaried with time of day, season, groundwater temperature, and relative air temperature. Additionally, burrow chimney construction by P. holifieldi covaried with daylength, groundwater temperature, relative air temperature, and precipitation. Out‐of‐burrow activity for both species was greatest at night and during periods of relatively cool groundwater temperatures and relatively warm air temperatures, which may be linked to thermal regulation behaviour. The probability of chimney construction by P. holifieldi increased with increasing daylength and decreasing precipitation and was highest during periods of cool groundwater temperatures and air temperatures. A distinct lull in activity from October through March for both species was likely to be the result of reproductive behaviours such as period of egg production and incubation within burrows. Identifying peak out‐of‐burrow activity periods for burrowing crayfish will allow collection efforts to be focused on periods of greatest activity, thereby facilitating the study of burrowing crayfish behaviour.