The neotropics of the Americas encompass a zone from the Caribbean and southern Mexico all the way to Argentina and Chile. In various places throughout that zone, particularly in Costa Rica -- with its preservation of rich biodiversity -- there is a wasp called Apoica, or the nocturnal paper wasp. The latter name is based on its paper-like hives. Apoica is a swarming wasp that releases a powerful chemical signal that corresponds to an explosive swarm at dusk that begins the night's activities.
Scientists acknowledge that there is a lot left to learn about wasps, and that there may be species yet unidentified. Nocturnal wasps present a special problem because as they are hard to locate. In recent years, British observers have become interested in wasps of two families the ichneumonidae and braconidae -- parasitic wasps inhabiting the British Isles -- that are apparently nocturnal.
Southeast Asia is another diverse region where there are many species about which scientists know very little. Among them is the provespa family of wasps, sometimes called night hornets. Even with such a threatening nickname, they are not aggressive, though they seem to be attracted to lights where they become one among many flying night nuisances to humans. Provespa are believed to feed on flies who are still during the night.
One characteristic that scientists look for in newly found wasp specimens that is a clue it might be nocturnal is the enlarged ocelli, or bigger eyes. Nocturnal wasps have larger, more oval eyes than diurnal wasps. While scientists are not prepared to say exactly how larger eyes assist in a nocturnal environment, most hypothesize that the size and shape of the eye assists in night vision and possibly sensitizes the organ to small points of light upon which the animal can orient.