Insectes Sociaux

, Volume 60, Issue 3, pp 383–388

Release of juvenile nematodes at hibernation sites by overwintered queens of the hornet Vespa simillima

Research Article

DOI: 10.1007/s00040-013-0303-9

Cite this article as:
Sayama, K., Kosaka, H. & Makino, S. Insect. Soc. (2013) 60: 383. doi:10.1007/s00040-013-0303-9


The nematode Sphaerulariavespae only parasitizes hornet queens and deprives them of fertility. To elucidate its transmission route, we observed the behavior of overwintered queens of Vespa simillima found around decayed logs of fallen trees—the principal hibernation sites for this species. We found that overwintered queens frequently visited those decayed logs in summer (late June to mid-August), hovering or walking on the surfaces of the logs, and sometimes entering holes or cracks there. These queens, unlike those visiting the hibernation sites in the fall, did not excavate wood to make their hibernacula, but often released juvenile nematodes there. In 25 % of the entries observed, we confirmed that juvenile nematodes had been released from the tips of the hornet’s gasters and thus transferred to the decayed logs. The timing of the host’s initial visit to decayed logs for nematode transmission corresponded well with the hatching of juveniles within the host’s body. These results suggest that the parasitic nematode manipulates its host to visit decayed logs in summer for its own transmission.


Entomoparasitic nematodes Hibernaculum Host manipulation Parasitism Social wasps Sphaerularia vespae 

Supplementary material

ESM_1 (release of nematodes): A sequence of behaviors of the parasitized queen of Vespa simillima releasing juvenile nematodes near the opening of a hole in the decayed log. These behaviors were videotaped in Sapporo on 21 July 2008. (MPG 16894 kb)

Copyright information

© International Union for the Study of Social Insects (IUSSI) 2013

Authors and Affiliations

  1. 1.Hokkaido Research CenterForestry and Forest Products Research InstituteSapporoJapan
  2. 2.Kyushu Research CenterForestry and Forest Products Research InstituteKumamotoJapan
  3. 3.Forestry and Forest Products Research InstituteTsukubaJapan

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