Adaptive Self-Defense: The Strategic Significance of Limb Autotomy in Freshwater Crabs Oziotelphusa Biloba

Background: Freshwater crabs Oziotelphusa biloba in paddy fields of Kerala exhibit extensive defensive self-amputation of limbs and understanding these autotomy patterns can provide insights into ecological and evolutionary significance of higher rate of autotomy response (41.4 ± 0.86%) than the marine crabs in nearby sea shore. Results: The morphometric characteristics in relation to the self-amputation process analyzed with observing 956 crabs during June to October 2022. The variability in rates of amputation among crabs with males (37.54 ± 1.14%) exhibiting slightly higher rates than females (35.96 ± 0.89%). The seasonal data in level of autotomy implies a higher autotomy rates in September and October, Right-sided limbs were more prone to injury (71.5% in males, 65.3% in females), Carapace width (30-35mm) and weight (15-16g) correlated with higher autotomy rates and Chelate legs were most susceptible to autotomy, particularly the right chelate leg in males (21.82 ± 1.6%) and both legs in females (25.87 ± 1.57% and 22.22 ± 1.91%). Conclusion: This study provides valuable insights into autotomy patterns and correlates in O. biloba, shedding light on the ecological and evolutionary significance of this defense strategy. The findings not only enlighten the predatory behavior in the field but also the energy conservation strategy during the injuries in limbs due to intraspecific interactions and cave building.