Authors:L. Vega, A. Torres, W. Hoffmann, and I. Lamprecht
insect [ 8 ]. Kaiser found for honeybees that the state of antennal immobility was an important sign for the depth of the sleep process in this socialinsect [ 9 , 10 ]. Sauer presented a newly developed video and computer technique for continuous
Authors:Midori Sakura, T. Hiraguchi, K. Ohkawara, and H. Aonuma
Pheromones are important cues for social insects such as ants. As a first step in elucidation of pheromonal information processing mechanisms in the myrmicine ant, we investigated the morphological structure of the antennal lobe. Using autofluorescence imaging, labeling of neuronal filamentous actin, and reduced silver impregnation staining, the antennal lobe was found to consist of five compartments that, each received input from a different antennal sensory tract. Two major tracts of projection neurons, the medial and lateral antenno-cerebral tract (m-and l-ACT), originated from a different region of the antennal lobe. The m-ACT originated from the posterior part of the antennal lobe whereas the l-ACT originated from the anterior part. These results demonstrate a spatial segregation of function within the antennal lobe.
The ant, Formica japonica, is polyphagous and workers hunt other insects as foods. In this study, interspecific aggression was examined in the workers and queens. Behavior experiments demonstrated that interspecific aggressiveness was significantly higher in workers than queens. Workers showed predatory aggressive behavior towards crickets, on the other hand, queens elicited threat behavior but they didn’t attack crickets. In order to investigate neuronal mechanisms underlying regulation of aggressive motivation, the role of biogenic amine in the brain in evoking aggressive behavior was examined by measuring biogenic amine using high-performance liquid chromatography (HPLC) with electrochemical detection (ECD). No significant difference in the octopamine (OA) level was found between workers and queens, but the level of N-acetyloctopamine (NacOA) in the brain of queens was significantly higher than that of workers. This study suggests that OAergic system in the brain must involve in controlling aggressive motivation in the ants.
. H. and Pamilo, P. (1996): Evolution of SocialInsect Colonies - Sex Allocation and Kin Selection. Oxford University Press, Oxford.
Evolution of SocialInsect Colonies - Sex Allocation and Kin Selection