Behavioral strategies of the freshwater crab <i>Sylviocarcinus pictus</i> (Crustacea Brachyura Trichodactylidae) in severe aquatic environments in the Brazilian semiarid region

Severe environments, characterized by high temperatures and scarce rainfall, challenge organisms and may lead them to display behavioral adaptations to live in such areas. While there is a significant amount of research on behavioral adaptations to severe environments on land, aquatic habitats remain relatively understudied. In this study, we selected a population of <i>Sylviocarcinus pictus</i> crabs from the semiarid region of Brazil to investigate, describe, and quantify the behavioral repertoire of adult crabs in a laboratory setting. In the laboratory, we filmed (<i>n</i> = 10) adult crabs individually (five males and five females), for 72 consecutive hours. Subsequently, we analyzed and recorded their behaviors every 20 min, totaling (<i>n</i> = 240) videos analyzed. Based on the observations, we then constructed an ethogram with nine behaviors grouped into four categories: quiescence, environmental exploration, feeding, and self-cleaning. Our results indicate that, regardless of sex (<i>P</i> = 0.39), <i>S. pictus</i> individuals remained more quiescent during the light period (<i>P</i> &lt; 0.05), with males spending 82.71% of the time quiescent and females spending 91.96% of their time quiescent. Additionally, individuals showed a substantial increase in the frequencies of activity-related behaviors during the dark period (<i>P</i> &lt; 0.05), with no significant differences between sexes. Compared to other species, <i>S. pictus</i> proved to be even more quiescent, especially during the day, possibly in response to the harsh environmental conditions. In the natural environment, we observed crabs seeking shelter under rocks during the day, possibly as a response to high temperatures. These findings suggest that the crabs have developed behavioral strategies to optimize energy use in severe aquatic environments.

以高温、少雨为典型特征的严苛生境，对生物生存构成极大挑战，亦会促使生物演化出适配该类环境的行为适应策略。尽管针对陆地严苛生境的行为适应已有大量研究，但水生相关生境的相关研究仍相对匮乏。本研究选取巴西半干旱地区的彩绘泥蟹（*Sylviocarcinus pictus*）种群，旨在通过实验室饲养条件下的观测，探究、描述并量化成年泥蟹的行为谱。实验过程中，我们对样本量为10只的成年泥蟹（雌雄各5只）进行单只隔离饲养，并连续72小时录制其行为活动。随后，我们以每20分钟为间隔对其行为进行记录与分析，最终共分析视频样本240份（*n*=240）。基于上述观测结果，我们构建了包含9种行为的行为图谱，将其划分为四大类别：静息、环境探索、取食以及自我清洁。研究结果显示，无论性别（*P*=0.39），彩绘泥蟹在光照时段均表现出更高的静息占比（*P*<0.05）：雄性个体静息时长占总观测时长的82.71%，雌性个体则为91.96%。此外，个体在黑暗时段的活动相关行为频率显著升高（*P*<0.05），且该变化不存在显著的性别差异。相较于其他蟹类物种，彩绘泥蟹的静息占比更高，尤其在日间时段，这或许是对严苛生境条件的适应性响应。在自然生境中，我们观测到泥蟹会在日间藏匿于石块下方，这可能是为了规避高温环境。上述研究结果表明，彩绘泥蟹已演化出行为策略，以在严苛的水生生境中优化能量利用效率。

搜集汇总

背景与挑战

背景概述

该数据集研究了巴西半干旱地区淡水蟹Sylviocarcinus pictus在严酷水生环境中的行为策略，通过实验室观察记录了10只成年蟹在72小时内的行为，构建了包含9种行为的行为谱。研究发现，无论性别，蟹在光照期高度静止（雄性82.71%，雌性91.96%），在黑暗期活动增加，表明其通过行为适应优化能量使用以应对高温等环境压力。