Motion‐triggered laser photography shows burrowing crayfish activity patterns

1. Burrowing crayfish represent 15% of total crayfish species and 32% of
imperiled 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. 2. We evaluated activity patterns of two primary
burrowing crayfish species, Lacunicambarus erythrodactylus Simon &
Morris, 2014 and Procambarus holifieldi Schuster, Taylor & Adams,
2015 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. 3. 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. 4. 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 behavior. 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 the result of
reproductive behaviors such as period of egg production and incubation
within burrows. 5. 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
behavior.