Acetylcholinesterase 1 (AmAChE1) has low catalytic activity and is abundantly expressed in both neuronal and non-neuronal tissues. In previous experiments, we observed that AmAChE1 is rarely expressed in summer while highly expressed in winter. Through additional experiments, the expression of AmAChE1 was suggested to be associated with brood rearing status. Under the assumption that abnormal suppression of brood rearing activity may result in stressful condition in honey bee social community, it was further suggested that AmAChE1 is likely involved in stress management particularly during winter. We hypothesized that the increased docility usually observed in overwintering bees is likely an outcome of stress management in colony, which is mediated by AmAChE1 expression. To verify this, worker bees expressing abundant AmAChE1 were collected in early winter and injected with Amace1 dsRNA to knockdown Amace1. Then, the behavioral activity of the bees was investigated using the EthoVison video tracking system. Honey bees injected with Amace1 dsRNA showed significantly increased motility, which was strongly correlated with the suppressed expression level of AmAChE1 in the abdomen. No apparent reduced expression of AmAChE1 in the head was observed perhaps due to the limited efficacy of RNA interference in the blood-brain-barrier. Our finding suggests that behavioral activity can be regulated, at least, by AmAChE1 expression level in non-neuronal tissue (i.e., fatbody) perhaps via metabolic alteration.

Post-maternal social organisation of Amaurobius ferox (Araneae, Amaurobiidae) provides an opportunity to investigate the mechanisms of social behaviour in spiderlings while controlling for potential effects of maternal presence. Development and characteristics of locomotory behaviours in young individuals of the subsocial Amaurobius ferox were examined. Young collectively show a very rapid and linear locomotion in a short distance in response to an intruder in the natal nest. Such a locomotory behaviour of the spiderlings resembles the successive synchronised stepping towards prey of the permanently social spider, Anelosimus eximius. We observed the development of different types of locomotion relative to the age of young, collective tendency (i.e., proportion of individuals within the clutch engaging in the behaviour), and directional properties of the locomotion. Locomotory behaviours of spiderlings fell into two categories: ‘abrupt locomotion’ (AL), involving fast and linear movement over a short distance; and ‘ordinary locomotion’ (OL), involving slower movement over longer distances and times. The frequency of AL (abrupt locomotion) did not vary much throughout the days post-matriphagy, occurring for a limited period of time. On the other hand, the frequency of OL (ordinary locomotion) varied over the days post-matriphagy and increased during the maternal social period.