Sawfly

Drawing of the Sawfly stages

Sawfly, Schizocerina krugii

Drawing from Insects of the Luquillo Mountains, Puerto Rico, Juan A. Torres. Information compiled by Alan Mowbray, Interpretive Media Writer, EYNF/LEF

General Information

Sawflies are a group of insects related to wasps and bees. Their name is derived from the saw-like ovipositor the adult female uses to lay eggs. Adult sawflies closely resemble wasps, but do not sting. The larval or immature stages of sawflies are plant feeders and resemble hairless caterpillars. Sawflies often feed in groups and can quickly defoliate a portion of a tree or plant. Each species of Sawfly prefers feeding on a specific plant or group of plants.

Description

Schizocerina krugii adults are dark-colored with the female somewhat longer (8 mm/0.3 inches) than the male (6 mm/0.2 inches). They have thin, transparent wings with the female’s forewing span at 20 mm/0.7 inches while the male’s is 11 mm/0.4 inches. Forewings and the smaller hind wings hook together in flight. Larvae look very much like the caterpillar larvae of butterflies except that they are hairless and have more than six soft legs (butterfly larva have less than five).

Habits

The female’s saw-like ovipositor (egg-laying apparatus) punctures the host plant injecting her eggs into the surface to protect them while they develop into larvae. The location of the egg deposit can be distinguished by tiny brown marks in rows on the host plant. Complete metamorphosis sequence (egg-larva-pupa-adult) occurs with Schizocerina krugii.

Habitat

Schizocerina krugii larvae can be found on Seagrape (Coccoloba uvifera) Moralón (C. pubescens) and other Coccoloba plants, which have been introduced to the Luquillo mountains. They cause intense defoliation of these trees and are considered a pest.

Where to look for this animal in the EYNF

On or near the leaves of the seagrape plant.