Amphibian Crossing Surprise

Nepa apiculata crossing the road in Shelburne, VT

Amphibian migration season is here, and many people have been spending their nights helping frogs and salamanders cross the road.  While assisting these four-legged critters, it is not uncommon to see six-legged, eight-legged, or even no-legged critters, too!  At the Shelburne Pond crossing, a very unusual arthropod was recently spotted; the waterscorpion Nepa apiculata.

Despite their misleading name, waterscorpions are not scorpions, but insects in the “true bug” order Heteroptera.  What looks like a stinger on their posterior is actually a snorkel-like breathing tube that they use to get oxygen without sticking their heads above the waterline.  They have no stinger and cannot bite, so to avoid predations they simply blend in.

Most species of waterscorpions are long and skinny and resemble aquatic walking sticks, but Nepa apiculata has a highly modified body that resembles a dead leaf.  The dark brown abdomen even has a netted pattern, resembling leaf veins!  

In addition to using their camouflage to hide, waterscorpions use it to ambush prey. They grab smaller organisms with their front legs, which look like giant mandibles, and suck out the juices with their piercing mouth parts.    

A Six-spotted Fishing Spider (D. triton)
crossing a road in Shelburne, VT

While Nepa apiculata is widespread, entomologists describe it as being rarely encountered; yet four have been found during amphibian monitoring over the past two years.  People have many special experiences while helping amphibians during their migratory season.  In addition to spotting waterscorpions, other surprise encounters include hooting owls, howling coyotes, and slithering snakes. You never know what you’ll see on a “big night”!