Another usage of autotomized penis

Abstract We described and compared the mating behavior and morphology of the reproductive system in chromodorid nudibranchs, then, examined how extensively the unique usage of the penis (autotomy and sperm …

Trace conditioning as a test for animal consciousness: a new approach


Trace conditioning involves the pairing of a neutral conditioned stimulus (CS), followed by a short interval with a motivationally significant unconditioned stimulus (UCS). Recently, trace conditioning has been proposed as a test for animal consciousness due to its correlation in humans with subjective report of the CS–UCS connection. We argue that the distractor task in the Clark and Squire (1998) study on trace conditioning has been overlooked. Attentional inhibition played a crucial role in disrupting trace conditioning and awareness of the CS–UCS contingency in the human participants of that study. These results may be understood within the framework of the Temporal Representation Theory that asserts consciousness serves the function of selecting information into a representation of the present moment. While neither sufficient nor necessary, attentional processes are the primary means to select stimuli for consciousness. Consciousness and attention are both needed by an animal capable of flexible behavioral response. Consciousness keeps track of the current situation; attention amplifies task-relevant stimuli and inhibits irrelevant stimuli. In light of these joint functions, we hypothesize that the failure to trace condition under distraction in an organism known to successfully trace condition otherwise can be one of several tests that indicates animal consciousness. Successful trace conditioning is widespread and by itself does not indicate consciousness.

Social and environmental cues drive the intra-population variation in courtship behavior of a neotropical lekking bird


Sexual selection predicts evolution of secondary sexual traits favoring mating. Here, we address the within population variation in courtship display behavior among male White-throated Manakins, Corapipo gutturalis, from Central Amazonia. We repeatedly quantified the courtship display elements used by 16 males over multiple days and specifically tested whether male presence and displays at courts could be explained by variation in environmental conditions (forest shade with small sunny gaps, large sunny gaps, and cloudy), male age (juvenile or adult), or yet the social context (other males and female visits) during displays. Our results show that total male presence and time displaying varied with the total number of other males and female visits at the court. In addition, the type of courtship elements used in displays (assessed by principal component analysis) also varied with the presence of both females and other males on the court. Male age, however, did not influence male activity. Overall, the social context at the court was the strongest predictor of within-population variations in male courtship display, whereas light conditions only affected display duration. Variation in display repertoire with female presence might reflect variation in female preferences. In addition, similar displays among males of different age classes suggest a competitive, rather than cooperative lek system of White-throated Manakins in Central Amazonia.

Emergence of complex dynamics of choice due to repeated exposures to extinction learning


Extinction learning, the process of ceasing an acquired behavior in response to altered reinforcement contingencies, is not only essential for survival in a changing environment, but also plays a fundamental role in the treatment of pathological behaviors. During therapy and other forms of training involving extinction, subjects are typically exposed to several sessions with a similar structure. The effects of this repeated exposure are not well understood. Here, we studied the behavior of pigeons across several sessions of a discrimination-learning task in context A, extinction in context B, and a return to context A to test the context-dependent return of the learned responses (ABA renewal). By focusing on individual learning curves across animals, we uncovered a session-dependent variability of behavior: (1) during extinction, pigeons preferred the unrewarded alternative choice in one-third of the sessions, predominantly during the first one. (2) In later sessions, abrupt transitions of behavior at the onset of context B emerged, and (3) the renewal effect decayed as sessions progressed. We show that the observed results can be parsimoniously accounted for by a computational model based only on associative learning between stimuli and actions. Our work thus demonstrates the critical importance of studying the trial-by-trial dynamics of learning in individual sessions, and the power of “simple” associative learning processes.