Pigeons monocularly trained on the mirror image discrimination showed the mirror image reversal effect, but those trained on the single stimulus training showed the bimodal generalization gradients with peaks at S^D and its mirror image. Tests with radius stimuli indicated that pigeons do not discriminate “left” from “right” during the single stimulus training, whereas they discriminate “left” from “right” on the basis of their using eye in the case of the mirror image discrimination.

View full abstract

The purpose of this study is to investigate the alcohol preference in rats and to determine the utility of a new method; Alc-Alc two-bottle method.
Ss were 8 male albino rats 100 days old in Exp. I, and 11 male albino rats 75 days old in Exp. II. They were given access to 2 alcohol solutions of different concentrations, and the amount of each fluid consumed during a period of 24 hours was recorded. In a session of 8 days, such procedure was repeated on alternate days to control the effects of position and bottle. On non-test days water was available in the 2 drinking spouts. This test was conducted over every combination of 2 in 4 concentrations : 3, 5, 7, and 9 (vol. %). Test sequences were as follows : 3-5, 5-7, 7-9, 3-7, 5-9, 3-9, in Exp. I; 3-9, 5-9, 3-7, 7-9, 5-7, 3-5, 3-9, 5-9, 3-7, in Exp. II.
The main results : i) 3 types of preference were observed in the range of 3% to 9 %, the higher concentration preference, the lower concentration preference, and the middle concentration preference (See Fig. 1, Fig. 5 and Table 1). A greater difference in the concentration of a pair of the solutions tends to clearly reveal the type of preference (See Fig. 2 and Fig. 4). ii) The lower concentration preference observed here was considered to be confounded with alcohol rejection (See Fig. 3 and Fig. 6). iii) All rats rejected alcohol in the first session, and some of them turned to select the higher concentrations after a few sessions (See Fig. 4 and Fig. 6). iv) The patterns of selection in every pair of solutions were transitional to each other in most rats (See Table 1).

View full abstract

There are recognized three types of removing the obstacle from the nest, RB I, II and III, in the ant-lions. They remove the obstacles (the pieces of rubber in this experiment) from their nests with their posterior or dorsal parts of abdomens while moving backward with facing front by demolishing their nests and then build their nests again at the original (in both RB I and II) or near (in RB III) places. The removing behavior types above mentioned of both ant-lions of two species, Hagenomyia micans and Myrmeleon formicarius were compared each other. The results obtained are as follows.
1) The ant-lions, larvae of Hagenomyia micans were divided into three types, A, B and C, according to their body size in this experiment. The larger their bodies are, the broader the limits of the size of the obstacles they can remove are.
2) The larvae of Hagenomyia micans which can remove the obstacles from their nests show RB I, II and III when their nests have certain size.
3) In the RB I of the larvae of Hagenomyia micans the ratio D/R of the removing distance D to the radius R of the original nest is almost constant.
4) In the ant-lions of Hagenomyia micans the condition of sand making their nests i. e. higher or lower degree of homogeneity of sand particles has an important influence on their removing behavior. No matter whether the type of larvae is A or C, the removing behavior is observed more frequently in the latter than the former when the same obstacle is used in both the conditions of sand.
5) When the nests have the same sand condition as that at their own habitats in both species i. e. Sa I in Hagenomyia micans and Sa VII in Myrmeleonformi carius, the removing behavior is observed much more frequently in the former than the latter. This suggests an important ecological significance in the nest building power of both species.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract