Walking Stick

Habitat
This kind of stick insect is most abundant in the savannah regions of Costa Rica’s Guanacaste province. Other species of stick insects live in many different habitats in the country. These animals live most abundantly in wetter forests.

Range
This species largely sticks to the dry zones in the Guanacaste province in Costa Rica. Speaking of stick insects more broadly, there are 2,500 species living in Latin America, the West Indies, Europe, and Indonesia.

National Parks
Guanacaste National Park, Rincón de la Vieja National Park, and Santa Rosa National Park.

Physical Description
Phasmids, or stick insects, get their common name from their bodily camouflage: extraordinarily long, slender limbs and body segments; brown, green, or mixed coloration; and “sticklike” movement perfect for blending into their surroundings. Some species have wings as adults, but Calynda bicuspis does not.

Biology and Natural History
During the day this insect will grasp onto adjacent sticks of a tree or other plant and maintain a stiff position or sway back and forth for hours.

At night it abandons this discrete behavior to forage and mate. The male has claspers that he uses to hold the female during copulation, and he may ride on her back for several days. If he does this he can continue to munch on nearby leaves from his position. The female has a small “flipper” at the end of her abdomen; she uses this ovipositor to spring her eggs into the air so they are not all laid in the same place.

While all stick insects share a somewhat similar appearance, different species use different combinations of behaviors to stay alive. Some species have the camouflage coloration of C. bicuspis, but some can also change their color to their surroundings, like to a chameleon. Some will drop to the ground from their hiding place if they feel pursued. Phasmids have relatively fragile bodies, but some can grow a limb back if they lose it. Others that have wings may fly or make a warning sound. Certain stick insects may also pretend to be dead or expel nasty chemicals in self-defense.

Diet
Species in some regions only eat from certain host plants, but the stick insect in Guanacaste may be less particular about which plants it eats.

Height/Weight
A female Calynda bicuspis is over 12 cm long once she is mature. Male stick insects tend to be smaller than females. Size varies according to species, and some in the Amazon can be quite large.

Taxonomy
Order: Phasmatoptera
Family: Phasmatidae

Sources
Hogue, Charles L. Latin American Insects and Entomology. University of California Press: Berkely and Los Angeles, 1993.
Janzen, Daniel H. Costa Rican Natural History. Chicago: University of Chicago Press, 1983.
Massey, A. and D.M. Windsor in Janzen, Daniel H. Costa Rican Natural History. Chicago: University of Chicago Press, 1983.

-Amy Strieter, Wildlife Writer