Top 20 Most Common Insects in Idaho Falls

An unusually large and heavy species of moth, large yellow underwing (Noctua pronuba) is dreaded by gardeners for the larvae's habit of causing fatal damage to the base of virtually any herbaceous plant. Large migrations occur some years, but how those years are determined is not yet known. Its contrasting colors (yellow-orange and brown) are thought to confuse would-be predators.

Known for its aerial building mastery, 'Dolichovespula arenaria' or 'aerial yellowjacket', constructs nests high up in trees or manmade structures. Its architecture prevents predation and creates an opportunity for symbiosis, with smaller insects benefiting from its scraps. Intriguingly, the aerial yellowjacket's sting is especially potent to its peers, often resulting in the takeover of rival hives, thereby increasing their lateral gene flow and ecosystem diversity.

Ennomos magnaria, the maple spanworm moth, notched wing moth, notched-wing geometer or notch-wing moth, is a moth of the family Geometridae. The species was first described by Achille Guenée in 1858. It is found from coast to coast in southern Canada and the northern United States, south in the east to Florida and Louisiana and in the west to California. The wingspan is 43–60 mm. Adults resemble an autumn leaf. The wings are deeply and unevenly scalloped. They are bright orange yellow and variably spotted with brown and shaded with reddish brown toward the outer margin. Adults are on wing from July to early November in one generation per year. The larvae feed on the leaves of Alnus, Fraxinus, Tilia, Betula, Ulmus, Carya, Acer, Quercus, and Populus species. They are twig mimics with a green, brown or gray body with white spots. Larvae can be found from May to August. The species overwinters as an egg. Pupation takes place in a cocoon amongst the foliage of their host plant.

Lycaena rubidus, the ruddy copper, is a butterfly of the family Lycaenidae. It is found in the western mountains of North America. Adults lay their eggs on plants of the genus Rumex, which later become the larval food plants. This butterfly gets its name from the brightly colored wings of the males, which are important in sexual selection. Its larvae exhibit mutualism with red ants, and are often raised in ant nests until they reach adulthood. Adults are on wing from mid-July to early August.

Megachile pugnata is a species of North American bee in the family Megachilidae. It was described by Say in 1837. Females are 12-18 mm in length while male are somewhat smaller: 11-13 mm. The adults are active from June to September. Females of this species are oligolectic on the pollen of plants in the sunflower family, Asteraceae, and commonly visit ironweeds (e.g. Vernonia fasciculata) for nectar.

Speyeria coronis, the Coronis fritillary, is a butterfly of the family Nymphalidae of North America. It is common from Baja California to Washington and east to Colorado and western South Dakota and once reported in Alberta. This butterfly is mostly orange and yellow with distinct dark-brown bars on the topside. The wing margins are dark with lighter circles then dark crescents. Silvery spots predominate on the yellowish underside. Wingspan ranges from 60–86 mm (2.4–3.4 in). Larva feed on Viola species.

It is dark brown with two eyespots on the forewing with the upper larger than the lower. The wingspan measures 39–44 mm (1.5–1.7 in). Its flight period is from late June to late August.

In general, the butterfly has a wingspan of 2.5 - 3.5 cm, with males being slightly smaller than females. Females are further differentiated from males by their number of functional legs; females possess three pairs, while males do not utilize their shortened forelegs and thus only have two. The Canadian populations have been described as having white checked dark brown wings, a gray body, green eyes, and black and white banded antennae. There is a reddish tint towards the base of the forewings, and the ventral side of the wings are gray.

Erinnyis ello, the ello sphinx, is a moth of the family Sphingidae. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. It is distributed from Argentina through Central America to the United States as far north as Nevada. The wingspan is 75–85 mm. The abdomen has gray and black bands. The forewing upperside of the female is pale gray with a few dark dots near the outer margin, while the forewing upperside of the male is dark gray and brown with a black band running from the base to the tip. In both sexes, the hindwing upperside is orange with a wide black border. Adults are on wing year-round in the tropics and southern Florida. Adults feed on the nectar of flowers, including common soapwort (Saponaria officinalis) and Chinese violet (Asystasia gangetica). The larva feeds on a variety of host plants, including papaya (Carica papaya) in the family Caricaceae; poinsettia (Euphorbia pulcherrima), Mexican jumping bean (Sebastiania pavoniana), Cnidoscolus urens, and cassava (Manihot esculenta) in the Euphorbiaceae; guavas (Psidium spp.) in the Myrtaceae; and saffron plum (Sideroxylon celastrinum) in the Sapotaceae. The ello sphinx can be parasitized by the braconid wasp Microplitis figueresi.

The four-spot (Libellula quadrimaculata) is one of the large dragonflies and reaches a body length of 4 to 4.5 centimeters with wingspan between 7 and 8.5 centimeters. Each of the four wings has a striking dark spot in the area of the distinctive transverse vein (nodus), after which the species received both its scientific and its trivial name. This dragonfly is also known for its mass migrations in swarms of impressive dimensions. The entire stock is not considered to be threatened.