Heart Rate Responses To Different Temperatures In Juvenile Poppiana Dentata (Randall, 1840)

Temperature is one of the main factors that influences cardiovascular functioning in ectotherms. Hence this study sought to investigate heart rate responses of a freshwater crab species, Poppiana dentata, to different temperature exposures since the species generally reside in habitats of fluctuating physicochemistry. Heart rates were non-invasively determined in juvenile crabs for three temperature regimes, each over an 8-day session; A: temperature exposures of 26 degrees C (2 days) to 30 degrees C (3 days) to 26 degrees C (3 days), B: 26 degrees C (2 days) to 32 degrees C (3 days) to 26 degrees C (3 days) and C: a control at constant 26 degrees C. I kart rate variations were significant among the regimes (P < 0.05), with the median heart rate being highest for regime B (74 beats per minute or bpm) during the temperature insult (32 degrees C), relative to regime A (70 bpm) and the control (64 bpm). Notably, a suppression and inversion of the diurnal cardiac patterns occurred for regimes' A and B crabs respectively, with rates from the highest temperature insult not shifting back to pre-insult levels during recovery (26 degrees C). It is plausible that P. dentata may have compensatory cardiovascular mechanisms that account for these differential heart rate responses, possibly conveying adaptive strategies in its dynamic habitat conditions.