Effects of simulated precipitation extremes on crayfish (Procambarus clarkii Girard) oviposition in artificial burrows

Mature female Procambarus clarkii were housed individually in artificial burrows simulating conditions in natural burrows. Crayfish were exposed to conditions of simulated temporary flooding dislocation (Experiment 1) or simulated drought (Experiment 2). In Experiment 1, females were dislocated from burrows to simulate 0, 1, 3 or 6 temporary flooding dislocations, and in Experiment 2, females were exposed to the following simulated drought conditions: wet control (no drought), dry control (no free water), month-long periods without free water during July, August, September and October (1month drought), two consecutive months without free water (AugustSeptember), and three consecutive months without free water (AugustOctober). In Experiment 1, no significant differences in survival or oviposition rate were observed following transfer of individuals from settled/sealed' burrows to new burrow' containers, even after six consecutive dislocations. In Experiment 2, simulated drought of 2 or 3month's duration had a significant negative impact on oviposition. Survival was significantly reduced only among females exposed to no free water during the 6-month study. No spawning occurred without the presence of free water in the burrows, and when free water was absent during the peak spawning months of September and/or October, oviposition was delayed until free water was returned. These results indicate that brood female P. clarkii can withstand short-term conditions without free water in the burrow with little effect, but reproduction and survival are significantly reduced by prolonged drought.