ibit simple forms of eusociality. There are about 200 described species, distributed in five genera: Euglossa, Eulaema, Eufriesea, Exaerete and the monotypic Aglae, all exclusively occurring in South or Central America (though one species, Euglossa viridissima, has become established in the United States). The latter two genera are cleptoparasites in the nests of other orchid bees. All except Eulaema are characterized by brilliant metallic coloration, primarily green, gold, and blue (Figure 46).
A Nest of Orchid Bees.
Females gather pollen and nectar as food from a variety of plants, and resins, mud and other materials for nest building. Some of the same food plants are also used by the males, which however leave the nest upon hatching and do not return.
Male orchid bees have uniquely modified legs which are used to collect and store different volatile compounds (often esters) throughout their lives, primarily from orchids in the subtribes Stanhopeinae and Catasetinae, where all species are exclusively pollinated by euglossine males. These orchids do not produce nectar, and hide the pollen on a single anther under an anther cap; they are not visited by females. The whole pollinarium becomes attached to the male as it leaves the flower (Figure 47). Several flowers from other plant families are also visited by the bees: Spathiphyllum and Anthurium (Araceae), Drymonia and Gloxinia (Gesneriaceae),Cyphomandra (Solanaceae), and Dalechampia (Euphorbiaceae) contain one or more species that attract male euglossines.
A Male Orchid Bee with Highly Modified Legs. Image Courtesy Green Fly.
The chemicals are picked up using special brushes on the forelegs, transferred from there by rubbing the brushes against combs on the middle legs, and finally these combs are pressed into grooves on the dorsal edge of the hind legs, squeezing the chemicals past the waxy hairs which block the opening of the groove, and into a sponge-like cavity inside the hind tibia.
The accumulated "fragrances" are evidently released by the males at their d