Current Issue

Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Five-legged cricket in the bathtub: Ceuthophilus spp. (American camel crickets) and Diestrammena spp. (Asian camel crickets)

 

Super long antennae help camel crickets navigate dark places and powerful legs help them escape nosy entomologists.

 

One day last week as I prepped for my morning shower, I was greeted by a five-legged camel cricket in the bathtub. Now for some people this might be disturbing, but hey, if you’re a bug geek what could be better to get the morning off to a hopping start? Camel crickets, dromedaries of the insect world, are so named for their humpbacked appearance. Like their cousins the field crickets, camel crickets (a.k.a. cave crickets) have extraordinarily long hind legs and prodigious antennae. The antennae bear sense organs that enable camel crickets to detect food and avoid predators in dark, damp habitats such as the deep woodlands and caves in which they live. In a realm of perpetual darkness where eyesight is of little value, some cavernicolous species of camel crickets are blind.

 

 

Camel crickets seem to enjoy a warm shower in the morning.

Other episodes of Bug of the Week have featured invaders from Asia including emerald ash borer, brown marmorated stink bug, and kudzu bug, but more recently Asian camel crickets have captured the attention of the national media. Several years ago scientists learned that a new cricket on the block, the Asian camel cricket Diestrammena, had bested our native camel cricket, Ceuthophilus, as rulers of residential man-caves and basement bedrooms. Researchers at North Carolina State University conducted a national survey and discovered that in places like Maryland, Virginia, and the District of Columbia, more than 90% of the camel crickets found in homes were Asian camel crickets. Camel crickets in the genus Diestrammena were first detected in the United States in a greenhouse in Minnesota in 1898 and dubbed the greenhouse camel cricket. Who would have guessed that in little more than a century they would become a dominant home invader?

Fecal spots left by camel crickets create a foul ambiance to the interior of a tool shed.

Whether domestic or exotic, all camel crickets consume decaying organic matter such as leaves, roots, and fruits. They also devour rotting remains of other insects, including their kin. When not invading dwellings, camel crickets are found in tool sheds, damp wood piles, beneath upturned wheel barrows, or in cool dank spots such as a leafy redoubt behind a rubbish bin along the shaded, northern aspect of my foundation. In addition to engendering the “yuck” response, they are occasional pests because they nibble stored fabrics. In tool sheds their fecal remains stain wood and tools. Their annual home invasion begins in force late in summer and early autumn and they favor basements, garages, and crawl spaces with high humidity and low light levels. Like boxelder bugs, brown marmorated stink bugs, lady beetles, and field crickets, camel crickets enter homes through  portals, including cracks in the foundation, voids around basement windows, spaces beneath doors, and holes where plumbing and electrical utilities exit and enter. Little crickets enter early in the season of siege and often go unnoticed, but as they scavenge food and grow in size, they become more apparent. Though wingless, they have remarkable powers of locomotion. Long, powerful legs provide an uncanny ability to jump. Recently, as I chased one sartorial visitor around the bath tub, it easily cleared the edge of the tub - a leap more than ten times its own height. While this feat might seem trivial, in human terms this would be equivalent to Zach Lavine slam-dunking at a rim 60 feet above the court!

 

Sensory structures on the antennae and mouthparts help camel crickets decide what to eat.

Here are some helpful tricks to keep these curious crickets out of your home. Remove woodpiles and vegetation near the foundation of your home. These refuges are ideal sites for camel crickets to multiply and later enter your home. Caulk and seal all openings to the outdoors around the foundation. Replace and repair door sweeps and reduce levels of humidity in the basement. If you find crickets inside, you can capture them and place them outdoors. Or as one cricket aficionado noted, they make excellent fish bait. Fortunately, when wrangling these leapers, I have a long-handled insect net that gets the job done. If you are armed with a vacuum cleaner or jar, I wish you luck. Sticky traps such as those used for snaring roaches can be placed on the basement floor. I have found the corner junction of two walls to be a productive spot for catching crickets, as many species like to travel with a shoulder near a wall – a behavior known as thigmotaxis.  

Camel crickets will drop a leg when threatened by a predator. Looks a little like a turkey drumstick doesn’t it?

Ok, by now some of you might be wondering what’s up with the missing-one-leg thing. Here’s the deal. Many animals discard an appendage, often a leg or a tail, when attacked by a predator. The strange behavior of discarding an appendage is not uncommon for many insects such as crickets and walking sticks. A special muscle allows a leg or antenna to snap off at the insect’s will under the right circumstances. This phenomenon, known as autotomy, allows the insect to lose a leg and save its life by distracting a hungry predator. When the predator stops to examine or eat the severed limb, the bug makes its getaway. In many cases the insect regenerates the missing part. In addition to bugs, reptiles, birds, and mammals use this clever ploy. With Thanksgiving just past, the one-legged cricket reminded me of a turkey missing a drumstick. I love the drumstick and wish that turkeys had six of them. I could not help but ponder the disappointment of some poor predator when its camel cricket feast had but one big drumstick leg instead of two. Glad that turkeys don’t drop a leg and I hope your feasts this holiday season are filled with drumsticks.

References

The wonderful article “Too big to be noticed: cryptic invasion of Asian camel crickets in North American houses” by Mary Jane Epps, Holly L. Menninger, Nathan LaSala, and Robert R. Dunn was used as a reference for this story. Other references used in preparing this Bug of the Week were the article entitled “Autotomy in a walking stick (Insecta: Phasmida)” by Tara Lynn MaGinnis, and “The Insects: An outline of Entomology” by P.J. Gullan and P.J. Cranston.

To learn more about camel crickets, please visit the following web sites:

http://dx.doi.org/10.7717/peerj.523

http://www.ces.ncsu.edu/depts/ent/notes/Urban/camelcrickets.htm

http://www.wtop.com/109/3694474/How-to-rid-a-basement-of-invasive-species-of-crickets