Importance of Butterflies
Butterflies are not only familiar insects to most people, but many species are important both economically and ecologically. The larvae of some species are pests on crops, while others are rare specialists found only in specific habitats that support a specific plant.
Butterflies are especially important because of their of their long history of popularity. Like birds, butterflies have been studied for centuries, probably in part because of their aesthetic qualities. This long-standing popularity has allowed butterflies to be studied extensively, perhaps helping to build a base for much of the insect research conducted in years to come. For example, books such as The Aurelian (1766) depict the entire life cycle of one butterfly species, showing that these insects go through a complex metamorphosis that has later been found to occur in many other insect groups. Thus, perhaps much of the knowledge we have about insects today may stem from the early popularity of butterflies.
Butterflies are also economically important. Several species are efficient defoliators. Anyone who has a garden with cruciferous species like broccoli and cabbage knows the ravages of the cabbage white (Pieris rapae) firsthand. Others are important pests on other crops. The giant swallowtail (Heraclides cresphontes) is an important pest of the citrus industry in the Deep South.
At least one Nebraska butterfly is actually a predator as a larva. Several of the small blue butterflies in the Lycaenidae develop in ant nests and feed on developing ant larvae. How they manage this without being consumed themselves is still not fully understood. The harvester (Feniseca tarquinius) feeds on wooly aphids on alders as a larva. Though this certainly does not make them economically important, it shows that butterflies are not limited to feeding on plants.
Butterflies are also important as indicators of habitat quality. Many species only feed on one or a few plant species as larvae. These species are thus largely limited to areas in which these plants occur. This butterfly-plant relationship becomes even more complex as some species only feed on certain parts of the plant or only on plants of a certain age. For example, members of the lycaenid genus Celastrina feed on the developing fruits of the hostplant, and the flight of the adults is timed with the blooming of the plant so as to allow eggs to be laid at the base of the flowers. The rare swamp metalmark (Calephelis muticum) of the Great Lakes region feeds only on the relatively rare swamp thistle (Cirsium muticum). Though the swamp thistle is biennial (plant lives two years), the larvae only feed on first year plants. In some cases, habitat is more important than the occurrence of the foodplant. Though eastern red cedar (Juniperus virginiana) is common across much of Nebraska, the olive hairstreak (Mitoura grynea), which feeds on it, is largely restricted to areas of steep topography such as gullies and canyons. Thus, various butterfly species can be useful indicators of both the presence of various plant species and the general qualities of the habitat.