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Monday, October 13, 2014

Prophets and Phantoms

Mantid species

While most think of fall as a time when nature is waning and lifecycles are nearing their end, some things are just beginning.  This is the time of year when some of our most mysterious-looking insects, the praying mantids and the walking sticks, lay their eggs in anticipation of the next generation to hatch in the spring.   

The scientific order for praying mantis (Mantodea) comes from the Greek meaning 'prophet'  so named for its typical prayer-like stance.  This term is often misspelled as ‘preying mantis’ since mantids are a predatory species.  Several species exist in Texas, all of the genus Stagmomantis. Adult mantids are green to grayish brown, may reach 2 to 3 inches in length, and have well developed wings.  They have two grasping, spiked forelegs in which prey are caught and held securely while eaten. Their hunting relies greatly on their vision, and they can rotate their head nearly 300 degrees.  Consuming mostly insects, mantids are ambush predators that wait perfectly still until prey ambles near, and then strike with surprising quickness and agility. 

Praying mantids are experts at concealment, using their protective coloration to blend in with or mimic foliage, better snare their victims, and avoid predation themselves.  They do show a rocking behavior in which the insect makes a rhythmic, repetitive, side-to-side movement.  It is thought that this behavior may help them resemble vegetation blowing in the wind, but also allows them to discriminate objects from their background by their relative movement.  As generally sedentary insects, this behavior most likely replaces flying or running as a way to determine relative objects in their visual field.  When threatened they will stand tall, spread their forelegs, and fan their wings out wide to appear larger, and if further provoked will strike with their forelegs and attempt to pinch or bite.             

In the fall after mating, female mantids lay between 10 and 400 eggs, depending on the species. The eggs are typically laid in a frothy mass on the underside of a leaf or on a twig, which hardens to a tan or gray foam-like material called an ‘ootheca.’  If this egg case survives the winter, the nymphs emerge in the spring with voracious appetites, often devouring each other in their race to become mature adults.


Members of the Phasmatodea order of insects are commonly known as walking sticks, stick-bugs, ghost insects, leaf insects, and stick insects.  This scientific name comes from the Greek ‘phasma’ which means 'apparition' or 'phantom', and refers to many species closely resembling sticks and sometimes leaves.  At 16 species, Texas walking stick diversity is second only to California.  In fact, one species in Texas is the Giant Walkingstick (Megaphasma dentricus), which is the longest insect in the United States and grows to almost 7 inches!

Walking stick species
Our most frequently seen phasmid is the Common or Northern Walking Stick (Diapheromera femorata).  Adult males can be 3 inches long and are mostly brown, while females are larger at 4 inches and more of a greenish-brown.  Their long, thread-like antennae are about to-thirds the size of their body.  As part of their natural camouflage, their bodies are often further modified to include ridges resembling leaf veins and bark or bud-like tubercles, making them very difficult to spot. They are wingless, molt several times and may eat their shed skin as they grow to adult size.  

Phasmids feed mostly on the leaves of trees and shrubs, and often exhibit the same rhythmic movement as mantids, presumably to blend in to their surroundings and as  protection from predators.  At this time of year, the females lay anywhere from 100 to 1200 eggs individually, sticking them to vegetation or simply depositing them on the ground.   These eggs resemble tiny plant seeds and remain dormant until spring.  

While no doubt strange-looking and mysterious, mantids and phasmids are harmless to humans and beneficial components to keeping balance in our natural landscape.