Slaters Pillbugs and Woodlice: Isopoda

Physical characteristics: Adult sand isopods are flat from top to bottom and measure up to 0.6 inches (15 millimeters) in length and 0.3 inches (7 millimeters) across. Their bodies are almost paddlelike when viewed from above. The thorax is almost round and is followed by a long and pointed abdomen. The legs are thick and feathery in appearance.

Geographic range: They live in the western Atlantic Ocean, from Nova Scotia south to Florida.

Habitat: Sand isopods live along the shore and just beyond in the water, where they burrow in coarse, sandy bottoms.

Diet: Very little is known about the diet and feeding ecology of this burrowing species, but they are thought to be predators.

Behavior and reproduction: The rear pereopods are used to burrow in the sand. Mating occurs while adult sand isopods are buried in the substrate and may take up to several days. The females molt while they are in the grasp of the males. Two to six dozen eggs are produced in one brood each year. Juveniles measuring 0.1 (2.5 millimeters) long and 0.05 inches (1.25 millimeters) wide appear in spring and molt at least six times before reaching adulthood.

Sand isopods and people: This species does not impact people or their activities.

Conservation status: Sand isopods are not considered endangered or threatened. ∎

Sand isopods live along the shore and just beyond in the water, where they burrow in coarse, sandy bottoms. (Illustration by Bruce Worden. Reproduced by permission.)