Lightning talk - Room F (12:15 P.M.)

28. Habituation Learning in Mealworm Pupae (Tenebrio molitor)

Rodolfo Bernal-Gamboa-National University of Mexico, Mexico, Jesús García-Salazar-National University of Mexico, Mexico, A. Matías Gámez-University of Cordoba, Spain

The decline of response as a consequence of repeated stimulation is known as habituation. The goal of the present experiments was evaluating the habituation of abdominal contractions in the pupa of Tenebrio molitor. Both experiments consisted of two phases. During Phase 1, all groups were exposed to a continuous stimulus (light in Experiment 1 and vibration in Experiment 2). At the beginning of this phase, pupae showed a high number of abdominal contractions, however, during the last minute of Phase 1, the number of abdominal contractions were lower. In the next phase, the pupae were divided in different groups to test for response recovery. We found an increase in the abdominal contractions when subjects were exposed to a different stimulus, be it within the same or in a distinct sensory modality. In addition, we also reported response recovery when the pupae were re-exposed to the original stimuli after a resting period. Results indicate that the increase in responding cannot be explained by neither sensory adaptation, nor fatigue. The findings are consistent with the perspective that suggests that habituation plays a major role in the survival of the species, even in non-feeding developmental stages.

29. Experience of nearer future events may extend possible time horizon in anticipatory contrast in rats

Mikita Nishikawa - Kanazawa University, Tohru Taniuchi - Kanazawa University

Flaherty and Checke (1982) found that rats refrained from drinking a less preferable saccharin solution in anticipation of a more preferable sucrose solution given later. The purpose of the present study was to examine whether previous experience with shorter inter-solution interval (ISI) leads to reliable anticipatory contrast under longer ISI. Rats were given 0.15% saccharin solution first and then 32% sucrose solution after ISI. Control rats were provided only with a first saccharin solution. Rats showed a reliable anticipatory contrast effect under ISI of 5 min but not of 30 min. However, once rats showed a reliable anticipatory contrast with a 5 min ISI, such a reliable anticipatory contrast was maintained even with an extended 30 min ISI for a long period. The anticipatory contrast under 30 min ISI quickly disappeared if the presentation of the subsequent sucrose solution was discontinued. These results suggest that a possible time horizon in the anticipatory contrast setting in rats can be extended through previous experience with shorter ISI.

30. An exploratory study on contexts, developmental changes and functions of mare-foal vocalizations in domestic horses (Equus caballus)

Chisato Wada - Graduate School of Humanities and Human Sciences, Hokkaido University Noriko Katsu - Graduate School of Arts and Sciences, The University of Tokyo; Japan Society for the Promotion of Science Ikuma Adachi - Primate Research Institute, Kyoto University Masahito Kawai - The Field Science Center for Northern Biosphere, Hokkaido University Ayaka Takimoto-Inose - Graduate School of Humanities and Human Sciences, Hokkaido University; Center for Experimental Research in Social Sciences, Hokkaido University

Domestic horses (Equus caballus) use about 10 types of vocalizations to communicate with conspecifics. It has been suggested that mares use the whinny and the nicker as contact calls, and foals use the whinny to regain or maintain contact with their mothers from early in their life, the detail of the contexts, developmental changes and functions of mare-foal vocalizations remain unclear. In this study, we investigated when mares and their foals use vocalizations, how the vocalizations change with the development of foals and what mare-foal affiliative behaviors are facilitated by the vocalizations. We observed 13 mare-foal pairs of Hokkaido native horses by focal sampling method from several weeks after birth of foals to weaning. We started each observation when the mare and her foal were within two body length, and recorded the focal pair’s vocalizations, behaviors and distances. The results revealed that the mare-foal maximum distance before reunion increased the occurrence of the mare-foal vocalizations and the age in weeks of the foals decreased the occurrence of the mare-foal vocalizations. We also found that vocalizations by foals reduced time taken to suckle after reunion and vocalizations by mares decreased the probability of them terminating suckling bouts. These results suggest that mares and foals vocalize when feeling anxiety from being apart from each other and such anxiety becomes weaker as the foals grow, and the mare-foal vocalizations have the function to facilitate suckling after reunion.

31. Forgetting as a function of delay and amount of information in spider monkeys

Reynoso-Cruz J. Eduardo-Universidad Nacional Autónoma de México, Hernandez-Salazar Laura Teresa-Instituto de Neuroetología, Nieto JAvier-Universidad Nacional Autónoma de México

The forgetting curve is a phenomenon in which animals forget as time passes. Spider monkeys had been tested previously and their performance suggested a reduction in accuracy as a function of time, but this reduction only occurred after 30 minutes. However, the method used a small number of trials, reducing the reliability of the measures. To solve this problem and to prove the effect of information in the forgetting process, we ran an experiment combining delays (0, 5, 10, 20, and 30 s) and the number of containers in which a reward could be hidden to retrieve (2, 3, 4, 5, and 6). Our data suggest that the delays, the container, and the interaction between them affect the forgetting process in a direct relationship: the longer the interval, the more information forgotten. An analysis of the mistakes shows that the individual codes the information using a code of spatial information. An additional experiment using color in the containers did not show evidence that the monkeys code the color to increase their accuracy, but to maintain the spatial information for a longer time. In conclusion, time and the amount of reward had an effect on the forgetting process, since spider monkeys code the location based on spatial information, and are capable of using discriminative stimulus to maintain spatial information.

32. Discrimination of frontally and laterally oriented conspecific faces in Bengalese finches

Wei Chen - The University of Tokyo, Kazuo Okanoya - The University of Tokyo

Animals detect others’ gaze direction to enable adaptive behavior. Because of the flat eye structure in birds, eye movement are smaller than most mammals. As a result, head movements play a larger role in gaze shifts in birds. Additionally, recent studies have demonstrated that most birds with laterally placed eyes usually turn their head to the targets by their lateral face. We used Bengalese finches (Lonchura striata var. domestica) to examine whether songbirds can discriminate conspecific frontal and lateral face and whether there is a boundary in head angles to discriminate. In the experiment, birds were trained by operant conditioning to discriminate stimulus composed of conspecific frontal and lateral pictures of four adult Bengalese finches. In the first training phase, we present a set of the stimuli from one adult Bengalese finch. When the subject is correct 90 percent, we add one more set of stimuli until up to four. After training, the subjects were tested with different head angles between frontal and lateral stimuli which shot from same Bengalese finch in training. At present stage, eight out of nine birds finished discrimination training and test sessions. We found that Bengalese finches can discriminate conspecific gaze direction by discriminating the frontal and lateral face angles. Furthermore, birds needed less trials to achieve the criteria as stimuli sets increased. However, it seems unlikely that there exists a discriminate boundary among the face angles. (Supported by JSPS #4903, JP17H06380 to K.O)