Repertório comportamental e interações sociais de machos de Macrobrachium acanthurus (Wiegmann, 1836) (Crustacea, Palaemonidae) em condições controladas

Abstract

Animal behavior has been an important tool to understand the biology, ecology, and actions performed by species. With environmental changes, habitat degradation, and growing cultivation environments, knowledge of the normal behavior of species is a strong ally to contribute to conservation and animal welfare. In this study, we sought for the first time to understand the behavioral patterns exhibited by males of the freshwater shrimp Macrobrachium acanthurus, describing all exhibited behavioral patterns. In addition, we seek to understand how luminosity interferes in the activity cycle, and if the morphological variation of the propod influences the daily activities of the species. For this, laboratory tests were carried out, where it was possible to control the environment variables, simulating an environment similar to the natural one. Two experimental groups were filmed for 5 consecutive days, one group in light phase simulating daytime photoperiod, and the other group in dark phase simulating nighttime photoperiod, during 80 hours of observation. The results allowed us to identify 32 behavioral acts divided into 8 categories that correspond to locomotion, digging, inactivity, feeding, cleaning, approach and distance. The footage revealed that the animals show activity during all time bands, however, they tend to remain inactive during the day, presenting a higher level of activity in low light, causing the species to be classified as twilight/night. During the dark phase, the length of the propod was related to activity behaviors, but not related to aggressive behaviors. This shows that the morphological characters related to the larger size of the propod and the darker color of the animals are determining characteristics for domain formation, demonstrating that aggressive interactions are not the only tools used for the social organization of the species.