Home >> Science & Nature >> Insects & Science

How a Cruiser Butterfly Adapts to a Biome

One of the most colorful and familiar group of butterflies in Southeast Asia, the cruisers comprise the four species of the Vindula genus. Like many butterflies and birds, cruiser species are sexually dimorphic: only the males bear the trademark bright orange coloration, whereas the females are a less conspicuous gray, but do share a similar pattern. Cruisers inhabit both forests and open countrysides in Southeast Asia, Australia and the South Pacific Islands. Even as pesticide use and habitat destruction strains butterfly populations worldwide, cruisers have persisted, in part due to a number of behavioral and physical adaptations to their environment.

Mimacry and Camouflage
- Like many species, cruisers utilize mimicry and camouflage to reduce the risk of predation. All Vindula species possess one or two pairs of small, circular "eyespots" on the rear of each hindwing. Eye spots have been shown to reduce susceptibility to predators, not by mimicking the eyes of larger animals as once thought, but by startling predators with the conspicuousness of the spots. In Thailand, Vindula erota is commonly called the banded treebrown butterfly, as the underside of its wings is brown and cryptic, camouflaging the butterfly in the dry foliage, common in their forested habitats. Similarly, the unusual chrysalis of cruisers strongly resembles a dead or decaying leaf, dry and brown with dark lines along the dorsal surface, much like a leaf's veins or ribs.
Mud Puddling
- Adult cruiser butterflies congregate around sites of moist dirt and soil -- a behavior known as "mud puddling." Most commonly observed in tropical regions, and nearly exclusively by males of the species, mud puddling is thought to be a means of replenishing nutrients, particularly sodium lacking in land plants. In his 1998 study, Jan Beck and his team looked at this phenomenon across 46 species of butterflies on the island of Borneo. They found the cruiser butterfly Vindula dejone preferred proteins, specifically albumin, over sodium chloride. The study's authors hypothesize that proteins obtained by mud puddling may increase reproductive success.
Flight
- Cruiser butterflies came by their name due to their robust flying and soaring abilities, allowing the species to propagate over long distances, even across the oceans of the Indo-Australian region. Their wings, spanning nearly 2.5 inches, are covered with both scales and fur. While males are more commonly seen on the ground or flying low, patrolling for mates along edge habitat, females achieve greater heights, even laying eggs at more than 5,000 feet in the tropical rainforest canopy.
Larval Food Plants
- Females cruisers lay their eggs on a vine of plants in the Passifloraceae family, which includes passionflowers and passion vines. Once emerged, the larvae -- caterpillars -- immediately begin feeding on the leaves of these plants. A favorite larval food plant of cruisers, the liana or viney Adenia has extremely toxic sap. Scientists Jan Beck and Konrad Fielder, in a study published in 2008, found that butterfly species utilizing lianas as a larval food plant live longer than those feeding on herbs, shrubs or trees.

Insects & Science