Dusky damselfish Stegastes fuscus relational learning: evidences from associative and spatial tasks

Abstract

This study investigated the ability of the dusky damselfish Stegastes fuscus to associate conditioned and unconditioned stimuli (single CS-US) and to find a specific place in a clueless ambiece (spatial learning). After tested for colour preference and showing no specific colour attractively, the fish were trained to associate a colour cue with a stimulus fish (conspecific). Fish were then challenged to locate the exact place where the stimulus fish was presented. Stegastes fuscus spent most time close to the zone where stimulus was presented, even without obvious marks for orientation. The results confirm that S. fuscus show single CS-US learning and suggest the fish ability for spatial orientation. Stegastes fuscus appears to use multiple senses (sight and lateral line) for cues association and recall, and appear to perform relational learning similar to mammals. These data suggest the importance of cognitive skill for reef fishes that may have contributed to their establishment and evolutionary success in such complex environment.

Memory retention of appetitive and aversive conditioning in the damselfish Stegastes fuscus

“…Therefore, we decide to use a conspecific as the appetitive stimulus, as S. fuscus promptly respond to its presence, seeking for the other fish. In another study testing associative learning in S. fuscus , the authors used a conspecific as unconditioned stimulus, showing the potential of social stimuli in learning tasks (Silveira et al ., ).…”

“…Stegastes fuscus is a territorial species that defends an area containing food and shelter from conspecifics and heterospecifics (Ferreira et al ., ; Osório et al ., ). Considering the ecological context of the species, it is important for an individual to learn and remember where it interacted with another fish (Silveira et al ., ) and the result of the encounter.…”

“…For the appetitive conditioning protocol, a similar procedure as the one above detailed was adopted with the exception that the focal fish was given a social stimulus (conspecific; Figure (b)), which is considered positive reinforcement for S. fuscus (Silveira et al ., ). The conditioning phase included two trials: on trial 1 (first day), each fish was placed on the white side of the tank for 60 s and the middle window was then opened to allow them to enter the black side.…”

Coffee time: Low caffeine dose promotes attention and focus in zebrafish

“…Although a number of studies have investigated distractors in fish decision-making (i. e. Silveira et al, 2015), and a few others in zebrafish under the effect of caffeine, none have studied these subjects in tandem. Apart from caffeine's effect of preventing fatigue, society also uses it to maintain focus on certain activities, such as studying (Hameleers et al, 2000), driving (Liu, Yao, & Spence, 2014), and similar attention and vigilance tasks (Foxe et al, 2012).…”

Can collective memories shape fish distributions? A test, linking space‐time occurrence models and population demographics

“…A variety of intrinsic and extrinsic controls, often working synergistically, are known to structure marine fish distributions (Planque et al 2011). For example, the use of visual stimuli to locate landmarks is well documented (Silveira et al 2015), whilst geomagnetic and olfactory cues provide important compasses for migrating salmon (Putman et al 2013). Furthermore, environmental gradients, predators, competitors and prey, population demographics and spatial memory can all be influential (Perry et al 2005, Rindorf and Lewy 2006, Loots et al 2010).…”