female attraction to male odors or to orchid fragrances has never been demonstrated in behavioral experiments. Instead, it is now thought that the function of the male odors is to signal male 'genetic quality' to females, because great effort must be expended by males to collect orchid fragrances and thus only the most fit males could gather complex odor mixes. This would constitute an unusual example of Zahavi's handicap principle, analogous to the male peacock's tail. The relationship between male euglossine bees and volatile chemicals is essentially unique in the animal kingdom. Scientists use single synthetic compounds as bait to attract and collect males for study; among them are many familiar flavorings and odors considered appealing to humans (e.g., methyl salicylate, eugenol, cineole, benzyl acetate, methyl benzoate, methyl cinnamate), and others which are not (e.g., skatole). It is also important to note that resource 'hot spots' wax and wane throughout the year as plants bloom and die, largely due to temporal changes, particularly between the changing of seasons. This often shifts euglossine bee preferences for certain chemicals over others. For Euglossa imperialis, studies have shown that there is a significant trend in chemical preference for cineole during later times in the year as opposed to methyl salicylate. In the local fragrance environment, a shift in the wind direction is another factor which may also cause another fragrance 'hot spot' to be included in the odor plume for euglossine bees. Neotropical orchids themselves often exhibit elaborate adaptations involving highly specific placement of pollen packets (pollinia) on the bodies of the male orchid bees; the specificity of their placement ensures that cross-pollination only occurs between orchids of the same species. Different orchid bee males are attracted to different chemicals, so there is also some specificity regarding which orchid bees visit which types of orchid. The early description of this pollination system was by Charles Darwin, though at the time, he believed the bees were females. Not all orchids utilize euglossines as pollen vectors, of course; among the other types of insects exploited are other types of bees, wasps, flies, ants, and moths. The male of Eufriesea purpurata is highly unusual among insects in seeking out and collecting large quantities of insecticide. Dressler (1967) discovered E. purpurata collecting aldrin and Roberts (1982) observed them collecting DDT in huge amounts from houses in Brazil, amounting to several percent of the bee's weight, without suffering