What Is A Palmetto Bug?

palmetto bug is the colloquial name for the Florida woods cockroach, Eurycotis floridana. As the name would imply, the species is native to Florida and the West Indies, where it is commonly found in trees, stumps, under decaying leaves, and cavities beneath tree bark.

If you are in walking in the woods in Florida and overturn some dead plant matter, odds are you will find this bug. The name “palmetto bug” comes from the insects’ tendency to be found in palmetto trees. “Palmetto bug” is also a common nickname for the American cockroach, but the two are distinct species.

A close up of an adult male Florida woods cockroach. Source: Mike Leffler via Flickr

Unlike other species of cockroach such as the German cockroach or American cockroach, Florida woods cockroaches are not normally known to be household pests. Instead, they prefer to live outside in damp areas with plenty of decaying plant matter. The insect is known for its defense mechanism in which it sprays a foul-smelling liquid upon perceived threats. This behavior is responsible for the bug’s variety of other common names, such as the skunk cockroach, the skunkroach, and the stinkroah,

Anatomy Of A Palmetto Bug

Most palmetto bug specimens come in at around 1.2-1.6 inches long and 1 in wide. Their color ranges from dark blackish-brown to a lighter reddish-brown. They tend to be squatter and broader than other cockroaches and their long flat body shape is useful for resting in the crevices they prefer. Like all insects, the palmetto bug has a segmented body composed out of a head, thorax, and abdomen. Each main segment is further divided into smaller segments. Surrounding the mesothorax are the bug’s tegmina, modified leathery forewings. Although palmetto bugs have wing-like appendages, they are incapable of flight. Like other species of roaches, they have two large compound eyes, two smaller simple eyes, and two long antennae attached to the head.

Florida woods cockroaches are not considered a sexually dimorphic species, but there are subtle differences in the morphology of males and females. Females have a wider abdomen that tapers and terminates in a V-shaped notch. Male abdomens are more narrow and end in a flat bottom, with two filaments on either side. The different abdomen shapes are necessary for copulation and reproduction.

Lifecycle And Behavior Of A Palmetto Bug

Florida woods cockroaches subsist primarily on decaying plant matter like leaves and bark, as well as lichens, molds and other microflora. Due to these feeding habits, the species is not known to invade human living spaces. They prefer to make their homes in stable domiciles like fallen tree trunks or dead tree stumps. However, they have been known to sometimes infest the foundations of old buildings; places that might have old rotting wood. In addition to serving an ecological role as natural mechanisms for removing decomposing organic material, Florida woods cockroaches also form the base of the food chain for a number of predators, such as spiders, lizards, rodents, and birds.

Florida woods roaches are thigmotactic, meaning they primarily interact with their environment through touch. The reliance on physical contact makes the insect favor tight enclosed spaces, as the constant contact helps them keep their bearings. Attached on their legs are various chemoreceptors that they use for taste. They generally do not like light, and will actively move to get out of well-lit and warm areas.

Florida woods cockroaches in their normal habitat. They like damp enclosed spaces, such as the interior of dead tree or under piles of dead leaves.  Source: WikiCommons

Florida woods cockroaches reach sexual maturity after about 150 days. At that point, the females will begin to produce their first eggs, regardless of fertilization. If a female never mates with a male, she is still able to reproduce via parthenogenesis, the development of an embryo without fertilization. Nymphs produced from parthenogenesis, however, will never reach sexual maturity, thus preserving the need for males for successful reproduction. On average, the bug lives for about 1 year.

Males and females reproduce via a complicated series of dances and gestures. After copulation and fertilization, the female with lay her eggs in groups of about 20 in a damp and stable location. Once laid, eggs take about 50 days to hatch, after which the newly hatched nymphs go through 6-8 molts before reaching adulthood in 100-120 days. Like some other species of roaches, rearing nymphs in isolation from one another causes them to take longer to develop and cause them to have problems functioning around others of their species. It is thought that certain pheromone secretions from other nymphs are necessary for proper growth and development. Palmetto bug ootheca (egg sacs) are susceptible to infection by some species of parasitic wasp. The wasps will lay their larvae on the egg sacs which become food for the parasite larvae.

Perhaps the most distinctive feature of Florida woods cockroaches is their spray defense mechanism. When threatened, the insect will spray a foul-smelling liquid upon potential threats. The liquid is composed mostly of different organic acids and serves as an irritant for invertebrate and vertebrate predators. After spraying, it can take up to 60 days for the bug to replenish its liquid stores, making the spraying a one-time-event for an individual cockroach. The spray plays two functions: First, it serves to deter antagonists. Second, the spray releases a pheromone in the air which elicits an escape response from other cockroaches. In other words, the roach “tags” the potential threat with the spray as a warning sign to others of its species. They are not known to bite, but will if their initial spray defense is ineffective.

Such behavior is just another example of the complex chemical signaling behaviors exhibited by roaches. Florida woods cockroaches frequently communicate with the release of chemicals to signify viable sources of food, safe locations to live, and potential threats and predators. There is also evidence that Florida woods cockroaches can even recognize the unique chemical secretions of other roaches and distinguish between family members and non-members. Each roach’s unique chemical profile essentially serves as its name tag and cockroaches can communicate this information via antennae contact.

Alex Bolano

Alex Bolano is a graduate of UMSL with his MA in philosophy, with an area of concentration in the history and philosophy of science. When he isn’t nerdily stalking the internet for science news, he enjoys tabletop RPGs and making really obscure TV references.

Cite this article as:
Alex Bolano. What Is A Palmetto Bug?, Science Trends, 2018.
DOI: 10.31988/SciTrends.25098
*Note, DOIs are registered Friday weekly and therefore may not work until then.

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