Variable checkerspot

The variable checkerspot or Chalcedon checkerspot (Euphydryas chalcedona) is a butterfly in the family Nymphalidae. It is found in western North America, where its range stretches from Alaska in the north to Baja California in the south and extends east through the Rocky Mountains into Colorado, Montana, New Mexico and Wyoming. The butterfly is usually brown or black with extensive white and yellow checkering and some red coloration on the dorsal wing. Adult wingspan is 3.2–5.7 cm (1.3–2.2 in). Adult butterflies feed on nectar from flowers while larvae feed on a variety of plants including snowberry (Symphoricarpos), paintbrush (Castilleja), Buddleja, Diplacus aurantiacus and Scrophularia californica.

During the breeding period, males congregate around larval host plants to encounter females. Males court female butterflies via physical displays. Successful courtship leads to copulation, when the male deposits a nutrient-rich spermatophore in the female. In addition, males also secrete a mating plug during copulation that hinders the ability of females to mate with other males.

Pregnant females look for host plants like Diplacus aurantiacus that are close to nectar sources when they lay their eggs. The larvae that emerge from the eggs feed and live on these host plants, some of which have developed strategies to deter larvae from eating their leaves. After moving to a darker and more secluded site, larvae enter diapause, emerging between January and March with pupation usually beginning in April.

The variable checkerspot is a potential food source for many avian predators. Due to a larval diet rich in catalpol, this butterfly has developed a strategy of unpalatability to deter avian predation. In addition, coloring plays a part in the defense strategy of the butterfly; intense red coloration deters predators from attacking them.

The variable checkerspot is a member of the order Lepidoptera, which contains the butterflies and the moths. It belongs to the family Nymphalidae, which also includes the tortoiseshells and the admirals. The variable checkerspot is part of the genus Euphydryas, which contains other checkerspot butterflies like Euphydryas editha and Euphydryas phaeton. There are ten subspecies of Euphydryas chalcedona. Additional information is required to determine the conservation status of some subspecies.

The variable checkerspot is usually brown-black with extensive yellow, red and white spots on the dorsal wing. Their underside usually contains yellow and orange bands. However, as its name suggests, the butterfly is highly variable in appearance. Dorsal color can range from a brick-red background with brown and yellow markings in Sierra populations to yellow and black in northern Californian populations. Adult wingspan is 3.2–5.7 cm (1.3–2.2 in). The species is visually similar to Euphydryas anicia, with the only notable difference being their male genitalia.

The variable checkerspot is found across western North America, ranging from Alaska in the north to Baja California and Mexico in the south. Its habitat is bounded to the west by the Pacific Ocean and it extends east past the Rocky Mountains into Montana, Wyoming, Colorado and New Mexico.

The butterfly's habitat encompasses a large variety of environments, including sagebrush flats, desert hills, prairies, open forests and alpine tundra.