Heart rate responses to different temperatures in juvenile Poppiana dentata ( )

• Main Authors: D. S. Singh, M. Alkins-Koo, L. V. Rostant, A. Mohammed
• Format: Article
• Language: English
• Published: Instituto Internacional de Ecologia 2019-04-01
• Series: Brazilian Journal of Biology
• Subjects: frequência cardíaca; caranguejos jovens; Poppiana dentata; variação de temperatura
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-69842019005002102&lng=en&tlng=en

Abstract 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 °C (2 days) to 30 °C (3 days) to 26 °C (3 days), B: 26 °C (2 days) to 32 °C (3 days) to 26 °C (3 days) and C: a control at constant 26 °C. Heart 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 °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 °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.