Polyrhachis lamellidens is a temporary social parasitic species. When a newly mated queen encounters a host worker, it opens its jaws, mounts and rubs the body of the host worker, called rubbing behaviour. This behaviour is different from aggressive behaviour and is considered to be a preparatory action before invasion of the host colony. However, it is unclear what cues trigger rubbing behaviour. Therefore, in this study, we used glass beads that imitated the insect body surfaces and searched for triggers. Although P. lamellidens did not respond to the cuticular compounds only, cuticular compounds and chitin coatings on glass beads elicited responses that were similar to those towards live samples. The rubbing behaviour of P. lamellidens was elicited in response to a cuticle-like surface that mimicked a procuticle by combining the compounds with chitin. These results suggest that host recognition and nest-mate recognition are supported by different mechanisms.

Polyrhachis lamellidens is a temporary socially parasitic ant whose new queen utilizes other ant species in the early stages of colony foundation. Field observations and rearing experiments suggest that Camponotus japonicus is a host species of P. lamellidens. It is presumed that Camponotus obscuripes is also a host of P. lamellidens by rearing experiments and field observations; however, there are no records of P. lamellidens workers or brood coexisting in C. obscuripes colonies in field observations, and there is no clear evidence that C. obscuripes is a natural host of P. lamellidens. We conducted detailed field observations, behavioral tests, and rearing experiments to show that C. obscuripes is a host of temporary social parasites. We found colonies with P. lamellidens queens, workers, and larvae intermixed with C. obscuripes workers in the field. Behavioral tests showed that workers of both species in mixed colonies did not attack each other and maintained nestmate recognition ability, which suggests a collaborative nestmate relationship. Furthermore, a rearing experiment confirmed social parasitism by P. lamellidens among C. obscuripes by producing a mixed brood-producing colony. These are the first field and laboratory records of temporary social parasitism involving P. lamellidens and C. obscuripes.

Halomonas meridiana strain Eplume2 (ATCC BAA-804) is a Gram-negative bacterium isolated from hydrothermal plume seawater in the Northeast Pacific Ocean at a depth of 2,000 m. Here, we report the complete genome sequence of this strain, which has a total size of 4.12 Mbp and a 56.6% G+C content.