flies quickly around the nest and may fall suddenly to the ground. This falling to the ground has only been observed in Dolichovespula species and its purpose is unclear. When small insects such as ants or spiders crawl on the nest the wasp responds by grabbing them in her mandibles and dropping to the ground. It is usually not necessary for her to try to keep these insects out of the nest as they are rarely seen to try and enter. Once there are some workers in a young nest the queen and workers cooperate to defend it. Curling Curling is one behaviour that is known only in the subfamily Vespinae and has been observed in nine species among three separate genera including the species D. media. Curling is an act of the queen where she curls her body around the pedicel of the nest when resting. The pedicel is the vertical part of the nest that gives it structure and what the combs are built around. This behaviour is almost always preceded by the queen turning around the pedicel before starting to curl. The queen most often curls at the pedicel for several minutes at a time. It is thought that this behaviour functions in brood incubation. This idea is supported by the evidence that the behaviour is present while there are only eggs and larvae in the nest but stops after many of the larvae have pupated. In addition, one study involving Vespa simillima showed that cell wall temperature rose by an average of 2.5-4.0C° (4.5-7.2 F°) and remained constant during curling. The rise in temperature and timing of the behaviour suggest that it is important in incubation for the offspring while they are eggs and larvae. Heat for later eggs and larvae is believed to be generated by pupa and other larvae as the colony size increases. Gastral vibration and tapping Another behaviour observed in D. media workers is gastral vibration. This is observed in workers of many Dolichovespula and Vespula species. Workers tap their gaster rapidly up and down onto the comb of the nest and this is associated with feeding of larvae. The behaviour typically occurs while wasps are walking on the comb and ceases after feeding each larvae a small amount of flesh and then resumes before feeding the next larvae. A behaviour that appears to be homologous to this is observed in the