Insect collecting Insect collecting has left traces in European cultural history, literature and songs (e.g., Georges Brassens's "La chasse aux papillons" ("The Hunt for Butterflies")). The practice is still widespread in many countries, and is particularly common among Japanese youths. Insects are passively caught using funnels, pitfall traps, bottle traps, malaise traps, flight interception traps and other passive types of insect traps, some of which are baited with small bits of sweet foods (such as honey). Different designs of ultraviolet light traps such as the Robinson trap are also used by entomologists for collecting nocturnal insects (especially moths) during faunistic survey studies.
Comma category difference between the two notions is that a natural transformation is a particular collection of morphisms of type of the form formula_182, while objects of the comma category contains "all" morphisms of type of such form. A functor to the comma category selects that particular collection of morphisms. This is described succinctly by an observation by Huq that a natural transformation formula_183, with formula_184, corresponds to a functor formula_185 which maps each object formula_8 to formula_187 and maps each morphism formula_188 to formula_16. This is a bijective correspondence between natural transformations formula_181 and functors formula_185 which are sections of both