Moths And Butterflies

Butterflies and moths are insects in the order Lepidoptera, meaning “scale winged” in Greek for the tiny scales covering their wings and body. Like all insects, Lepidoptera have a hard outer covering called an exoskeleton which is divided into sections with joints so the animal can move. Also like other insects, butterflies and moths have six legs, a head, a thorax, and an abdomen. They are found on every continent except Antarctica, and in nearly every environment, where they serve an important role in food chains. Recently compiled estimates of described species suggest there are ~150,000 to 160,000 Lepidoptera species, compared to ~115,000 to 120,000 ant, bee and wasp (Hymenoptera) species. (Zhang, 2011)

The insect order Lepidoptera comprises the butterflies, moths, and skippers. They can be distinguished from all other insects by their two pairs of scale-covered wings. They undergo complete metamorphosis: eggs are laid, from which larvae hatch, and a pupal stage follows, during which the final adult form takes shape.

Lepidoptera are renowned for their sense of smell. The females of most species release complex, species-specific chemical compounds (pheromones), which can be detected by males from great distances. The males locate the females by following their scent plumes, often producing their own pheromones, which are used at close range during courtship. Some moths also have a well-developed sense of hearing, which has evolved as a method to detect the sonar of bats, which are important predators of moths. One group of moths, the tiger moths (Erebidae: Arctiinae) actually produce sound to interfere with the signals of bats or to advertise chemical protection gained from plant compounds.

For most Lepidoptera species, the vast majority of the life cycle is spent in the larval stage. Most larvae feed on living plant tissue, primarily leaves, but also flowers, buds, seeds, stems, roots, and bark. Some feed externally; others are miners or borers. A few species stimulate gall formation on their host plants. Many species are very host-specific; others feed on a wide variety of plant species. The larvae of some species feed on fungi or detritus, and a few have become facultative predators or parasites. Most adult Lepidoptera live for only 1 or 2 weeks, and have a fairly specific flight period. Most adults feed on nectar, but many have atrophied mouthparts and do not feed at all, living on the fat reserves built up in the larval stage. Many species, particularly butterflies, are known to “puddle” at damp places, presumably to obtain dissolved minerals.

The Lepidoptera form an essential part of most terrestrial ecosystems. As herbivores, they help to regulate plant growth (through herbivory and nutrient cycling) and when their population levels are high they can act as agents of plant community succession. Many adult lepidopterans are important pollinators. Larvae and adults are major food sources for many other animals, including songbirds, bats, and other insects.

A few species of Lepidoptera are such good resource competitors with humans that they are considered pests. Although the proportion of species in this category is very small, it includes pests of food crops, trees and timber, and stored food products. Although only two moth species have larvae that eat silk and wool products, this extremely rare feeding habit is often misattributed to the whole group by the uninformed. Silk itself comes from human exploitation of the Silk Moth, Bombyx mori (Linnaeus).

The Lepidoptera constitute one of the four largest groups of insects, in terms of their diversity. About 180 000 species have been described (Biodiversity Institute of Ontario 2006), but many more remain undiscovered. The total number of species is probably between 300 000 and 500 000 (Scoble 1995; Kristensen et al. 2007). Most of the butterfly species have been described, but some groups of moths, particularly the micromoths, remain poorly known. The earliest Lepidoptera fossils are about 190 million years old (Grimaldi and Engel 2005), but most evolutionary radiation in the group occurred in conjunction with that of the flowering plants, in the Cretaceous Period, 65 to 145 million years ago.

A checklist of Butterflies found in Rocky Mountain National Park, Colorado, USA.

LepiMAP is the African butterfly and moth mapping project. LepiMAP is a joint project of the Animal Demography Unit and Lepidopterists' Society of Africa.

Learn more about this citizen science project on SciStarter.org.

Butterflies and moths are important pollinators. However, many species of butterflies and moths have been declining, partially due to loss of migratory and nectar corridors. Over 200 species of butterflies and moths undergo some type of migration, and the loss of appropriate habitat the distance of the migration routes has led to declining populations. Attempts to reverse this trend are being made by local jurisdictions, conservation organizations, and federal agencies. Compared to bees, butterflies and moths are often less efficient at transferring pollen between plants because frequently pollen does not stick to their bodies and they lack specialized structures for collecting pollen. Butterflies and moths probe for nectar and prefer flat clustered flowers that they can use as a landing pad.