Do cicadas bite or sting? What other mischief do they create?

 

Cicadas insert soda-straw-like sucking mouthparts called a beak or proboscis into plant tissues to obtain nutrients for growth and development. Adult feeding results in minimal damage to plants compared to injury caused when female cicadas use their ovipositor to slit branches. Into these wounds eggs are deposited in egg-nests. Eggs develop during spring and summer. Cicada nymphs will hatch from these eggs, drop to the earth, and develop underground for the next seventeen years.

 

In recent episodes we learned where Brood XIV cicadas would and would not be seen this spring. We also discovered what signs to look for in your yard as a presage to their grand appearance. This week let’s tackle a few questions that popped up in a recent conversation with the Weather Channel. Two of the most frequently asked questions regarding cicadas is “do they bite and do they sting?” Well, through my six decades of watching, catching, studying, eating, and photographing cicadas, my answer has been no, don’t worry about being bitten or stung by cicadas. However, following two messages from folks who listened to a television interview this week, I am scratching my head just a little bit about what cicadas can and cannot do with regard to biting and stinging. One viewer recounted an episode almost two decades ago when a cicada landed on their shoulder and pierced the skin leaving behind a zig-zag shaped mark. A second viewer shared an encounter with a cicada that attempted to probe her finger with its beak while she was holding the cicada during a “show and tell” demonstration with some children.

See the black proboscis or beak of the cicada between its front legs? Watch as it pushes its beak into the tree to find the vascular element called xylem which will be its source of liquid food for the next several weeks.

So, let’s dive into these questions about biting and stinging cicadas and see what might be afoot. We all learned in grammar school that one commonality of animals is that they are heterotrophs, that is, they cannot produce their own food but instead must eat other things for their sustenance. And when we think about animals eating, we think about biting, right? Biting usually involves something like what we humans do, jaws with mandibles removing chunks of food. Many insects like grasshoppers, beetles, wasps, and caterpillars have jaws that remove hunks of flesh or foliage as they feed. However, in many clans of insects, these jaw-like mouthparts have morphed dramatically through time into more soda-straw-like mouthparts, called piercing or sucking mouthparts, with the descriptive name of beak or proboscis. The beak has internal channels; one is used to remove liquid food from plants or animals which they feed upon, and another channel is used to inject saliva into the food item. Insects with sucking mouthparts include disagreeable rascals like bed bugs, mosquitoes, stink bugs, and lanternflies. Cicadas also have sucking mouthparts used to imbibe xylem fluid from plants on which they feed. So, do cicadas bite? Technically, you cannot bite with sucking mouthparts but you can suck and yes, cicadas do suck. Obviously, the next question is “do they suck on humans or pets?” The answer as far as I am aware is no. I have never heard of any human or animal losing blood to a sucking periodical cicada. These are obligatory plant feeders. The person mildly assaulted by a cicada shared that it did not break her skin. Also, she disclosed that the cicada had been confined for a long time and maybe it was tired of being held by a human. Who knows?

Young saplings and recently transplanted trees growing rapidly in the open are often heavily damaged by cicadas.

Well, what about stinging? Let’s dive into that. Stinging insects like bees, ants, and hornets, do so with an appendage at the tip of their abdomen called an ovipositor. Queens of these social insects use their ovipositor to lay eggs that hatch into workers. Workers are tasked with the onerous job of defending the colony. The ovipositors of defensive workers are connected to glands that produce venom, powerful chemical cocktails designed to bring intense pain to Winne the Pooh or other interlopers intent on raiding the colony for honey or brood. The ovipositor of most other insects is an appendage used to deposit eggs in a place where offspring can develop and thrive. As is the case with cicadas, ovipositors of these insects lack venom. Periodical cicadas use their ovipositor to cut slits into the tissues of plants, primarily trees and shrubs, where eggs of the next generation of cicadas develop before nymphs hatch and drop to the earth. As you might surmise, these ovipositors are stout and sharp enough to pierce the bark of a branch. Perhaps the person assaulted by a cicada was the unwitting victim of a misguided female cicada who mistook a human shoulder for a place to deposit eggs. Animal behavior is rife with mysteries and evolutionary mistakes, some for the better and some for the worse. If this assault was an attempt to lay eggs in a human rather than a plant, you can bet these foolish egg-laying genes will not last long in the reign of cicadas. 

Female cicadas use saber-like ovipositors to cut slits in the bark of small branches. These slits are called egg-nests. Watch as the female cicada moves her ovipositor in and out of an egg-nest where she deposits 20 to 30 eggs. She creates dozens of egg-nests which line small branches throughout the canopy of trees she visits. In some cases, weakened branches break and leaves die, creating so-called “flags” hanging throughout the crowns of cicada laden trees. Young saplings and recently transplanted trees growing rapidly in the open are often heavily damaged by cicadas. 

Wrapping trees in netting will prevent periodical cicadas from damaging branches of young trees.

My take is that the chances of being probed by the beak of a cicada or assaulted by a crazed, egg-laying female are very small. However, for the millions of homeowners that might be visited by periodical cicadas there is one potentially significant problem. This “dark side” of periodical cicadas manifests itself if you have small saplings or have recently installed young trees in your landscape. Egg-laying cicadas will slice branches to insert their eggs into egg-nests. This causes the tips of many branches to wither and sometimes die. Dying and dead terminals droop, resulting in a type of tree injury called flagging. Some injured terminals break and fall to the ground. Branches that do not break may eventually heal, but the wound-site may form a gnarly irregular swelling on the branch. Which plants are most likely to be affected? The bad news here is that periodical cicadas are broad generalists. Miller and Crowley (1998) studied 140 genera of trees at the Morton Arboretum and found more than half sustained injury caused by ovipositing females. Among the most severely affected were ones common to landscapes in the DMV, including Acer (maple), Amelanchier (shadbush), Carpinus (hornbeam), Castanea (chestnut), Cercidphyllum (katsura), Cercis (redbud), Chionanthus (fringe tree), Fagus (beech), Quercus (oak), Myrica (bayberry), Ostrya (hophornbeam), Prunus (cherry) and Weigela (weigela). Another study by Brown and Zuefle (2009) of 42 woody plant species added several new genera to the list and found all but 10 species were used by cicadas to lay eggs. Small rapidly growing trees with longer, more open branching habits found in young saplings were more heavily used for egg-laying. Trees at the edges of forests with rapidly growing branches exposed to sunlight often sustain more cicada injury. While ovipositional injury poses a threat to newly planted trees, for older and well-established trees flagging and limb breakage may occur in the short term, however, studies indicate that the long-term threat to tree vitality is minimal (Miller and Croft 1998).

How can you mitigate damage caused by ovipositing Brood XIV cicadas on young trees in your yard? Unfortunately, sometimes our knee-jerk reaction is to grab a can of insecticide and start squirting when we see a bug. In the case of periodical cicadas, studies have shown that the most effective deterrent to egg-laying cicadas is to wrap your saplings in netting that prevents females from laying their eggs. Ahern et al. (2005) found that linden saplings protected by netting with openings of 1 cm (0.4 inches) prevented cicadas from laying eggs whereas saplings treated with systemic insecticides or those left untreated received several hundred egg-nests along their branches.

Young linden trees protected by netting had virtually no egg-nests laid in their branches while those treated with a systemic insecticide or left untreated had hundreds of egg-nests deposited in their branches. Data from Ahern et al. 2005.

In future episodes we will explore when Brood XIV cicadas might appear and learn more about these strange and remarkable insects.

To learn how to properly protect your tree with netting from egg-laying cicadas, please watch this clever video.

Acknowledgements

Great references for this episode include “Does the periodical cicada, Magicicada septendecim, prefer to oviposit on native or exotic plant species?” by W. P. Brown and M. E. Zueffle, “Effects of oviposition by periodical cicadas on tree growth” by K. Clay, A. L. Shelton and C. Winkle, “Periodical Cicada (Magicicada cassini) Oviposition Damage: Visually Impressive yet Dynamically Irrelevant” by W. M. Cook and R. D. Holt, “Effects of periodical cicada ovipositional injury on woody plants” by F. Miller and W. Crowley, “The ecology, behavior and evolution of periodical cicadas” by K. S. Williams and C. Simon, and  “Comparison of Exclusion and Imidacloprid for Reduction of Oviposition Damage to Young Trees by Periodical Cicadas (Hemiptera: Cicadidae)” by R. Ahern, S. Frank, and M. Raupp. Thanks to two anonymous viewers who shared their stories with me and to my friends at the Weather Channel for allowing me to share cicada stories with others.  

Will Brood XIV cicadas appear in my yard? Here are some clues

Perfectly shaped for moving soil, greatly expanded forelegs enable the mature cicada nymph to create a pathway to the world above ground.

Last week we broke some news that here in the DMV some will see Brood XIV cicadas this year (Virginia), others will not (DC), and some might (Maryland). If you are fortunate enough to live in one of the twelve states where Brood XIV are known to occur, how will you know if cicadas are about to grace your yard? As many of you know, periodical cicadas are quite patchy in their distribution. In my neighborhood in Columbia, Maryland, folks along my street had tons of Brood X cicadas back in 2021, but just a few streets away, nary a cicada was to be seen. Several factors feature into local distributions of periodical cicadas. Changes in land use are primary factors. Periodical cicadas depend on woody plants as key places to conduct their boisterous choruses, mating rituals and locations to deposit eggs that usher in the next generation. Although soil-dwelling nymphs can feed on roots of herbaceous plants, xylem fluids from tree roots support fantastic densities of cicada nymphs as they grow underground for seventeen years. If you live in a neighborhood where development has denuded trees and removed soil in the last seventeen years, your chances of Brood XIV emerging in your yard are slim. Likewise, if your house sprouted up in what formerly was a field of hay or corn, your chances of welcoming periodical cicadas are, well, not so hot. Habitat fragmentation and urbanization with attendant impervious surfaces and soil compaction are two factors thought to disfavor populations of periodical cicadas. In several locations in the eastern United States, populations have dwindled or been extirpated over the last two centuries.

Beneath this stately old tree, a raccoon ravaged this lawn in early March. Were periodical cicadas the object of its gastronomic desire? Image credit: L. Kenigsberg

As periodical cicadas complete their juvenile development, here are some clues to help you know if you will see cicadas this spring or not. First, if your landscape supported cicadas back in 2008, odds are excellent that you will see them again this year. If you have moved into a home sometime after 2008 and you live in one of the states where Brood XIV historically appears, simply ask one of your long-standing neighbors if they saw cicadas seventeen years ago. If you live in Georgia, Indiana, Kentucky, Massachusetts, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, or West Virginia, you can see which counties in your state reported Brood XIV back in 2008 by visiting the Cicada Mania website. There are also several clues you can see in the landscape around your home over the next month or so that signal the presence of cicadas. First, let’s talk about a glorious feast that is underway for small wild and domestic mammals as periodical cicadas prepare an exit strategy from their subterranean crypts. Four years ago, as a presage to the massive emergence of Brood X, a curious homeowner sent fascinating images of impressive excavations of turf beneath a fine old tree. The perpetrator of this crime was a pesky raccoon intent on digging for its dinner. The lawn was, well, just collateral damage on the way to a fine meal. While the identity of the subterranean morsel was never confirmed, this type of behavior is characteristic of many small mammals that will find cicada nymphs and adults irresistible this spring and go to great lengths to find them.

After feasting on periodical nymphs beneath my holly tree, this handsome fox headed for the hills and almost escaped my camera.

Also, during the early days of spring in 2021, the year of Brood X, while emptying some coffee grinds in the compost at 6:30 AM, I surprised a very handsome red fox in the process of excavating a thirty-foot-long patch of earth beneath my stately Burford holly. A couple quick turns of the shovel revealed several Magicicada nymphs about six inches below the surface of the earth. Casual site visits to my neighbors’ gardens and further inspection of my landscape revealed several locations where fox and friends had been busy in Columbia, Maryland enjoying cicada snacks. Both foxes and raccoons have excellent night vision, a must for their nocturnal forays, and an extremely keen sense of smell that allows them to detect prey beneath layers of fallen leaves and soil. These wild small mammals are not the only ones whose special creature powers include super olfaction. A dog’s sense of smell is estimated to be more than 10,000 times more acute than a human’s. And yes, if it hasn’t started already, soon inquiries will arrive posing the question: “Why is the dog digging up my yard?” Chances are good that Fido knows a good snack when he smells one. Please, just don’t let him eat too many.

How might you know if cicadas will emerge in your yard? Here are some clues. Small mammals like squirrels, foxes, racoons and skunks are on the hunt for cicadas, turning over the soil in lawns and beneath trees. In moist soils cicada nymphs sometimes build mud turrets over their exit holes and in other places vast numbers of round dime-sized holes will appear. Under stepping stones and flagstone walkways, numerous cicadas may be found in their galleries. Amazing expanded forelegs shaped by millions of years of evolution enable cicadas to move earth and shape their escape tunnels.

In moist soils like this, cicadas build mud turrets over their emergence holes.

Soon it will be time for a suburban safari to your backyard to spot additional signs of the arrival of periodical cicadas. Look for holes in the soil about the size of a dime within the dripline beneath trees that have been in the ground for seventeen years or more. Historically, oaks, maples, crabapples, and hollies seem to be the big winners in my landscape. In addition to holes, periodical cicadas often build domed caps or tubular extensions known as turrets over their escape tunnels. This may be more common in wetter soils. If your landscape includes stepping stones or flagstone pathways over soil, lift a few and you may discover lateral tunnels as cicadas encounter the impenetrable barrier and attempt to make their way to the edge of the barricade to reach the world above ground.

Lifting a stepping stone may reveal cicada nymphs peering out of their escape tunnels. Image credit: Kristin Jayd

No holes under trees? Don’t panic, new holes may show up over the next several weeks. During past emergences of periodical cicadas, a common question has been, “how do cicadas moved about underground and how did they construct their exit galleries? The answer lies in the clever adaptations of their forelegs. Their forelegs bear greatly expanded femurs and tibias which act like the blade of a shovel to move soil. Millions of years of evolution for a life in two worlds, one underground and one above the earth, have perfected the tools necessary for cicadas to succeed in both. In upcoming episodes, we will learn more about these remarkable insects.       

Acknowledgements

Bug of the Week thanks L. Kenigsberg for providing the nice image of lawn pillaged by a raccoon that served as the inspiration for this episode. Kristin Jayd and Paula Shrewsbury also provided images and assisted with videography.

Will Brood XIV cicadas appear in the DMV? Yes, no, and maybe – Magicicada septendecim, Magicicada cassini and Magicicada septendecula

 

Will cicadaphiles in the DMV have a chance to see beautiful periodical cicadas near their homes this year? Yes, no, and maybe.

 

During the past two months, Bug of the Week’s peregrinations took us to the tropical rainforests of Belize to visit stingless bees, sassy assassin bugs, red rump tarantulas, headlamp beetles, incredibly fast whip spiders, fungus-loving leafcutter ants, and rapacious army ants. This week we hop-scotch fifteen hundred miles north to the DMV to check on the progress of Brood XIV (14) periodical cicadas. Last week journalists proclaimed the upcoming arrival of millions (or is it billions?) of cicadas set to emerge in a dozen eastern states. The appearance of periodical cicadas in the DMV this year looks like a definite yes, no, and maybe. According to the Cicada Mania website, a source of all things cicada, Virginia is a definite yes. Brood XIV is a brood of all three species of 17 - year cicadas, Magicicada septendecim, Magicicada cassini and Magicicada septendecula, that was last seen in 2008 in Botetourt, Lee, Russell, Scott, Smyth, Tazewell, and Wise counties. Unfortunately, the District of Columbia appears to be a definite no. While historical maps by Charles Marlatt and Roy Troutman appear to show Brood XIV in D.C., more recent compilations indicate that this is not the case.

Seventeen years ago, back in 2008, eggs of periodical cicadas hatched. After stretching their legs a bit, tiny nymphs dropped form tree branches down to the earth below. They entered the soil sometimes using the very holes from which their parents emerged but few weeks earlier. After sucking sap from plant roots for a few years, they grew to the size of a jelly bean. But just three years ago, they were almost an inch in length. In locations where they will emerge you can visit Brood XIV cicadas by carefully turning the soil with a shovel. After your visit, please return them to the soil and gently cover them with earth so they will emerge with the rest of their brood mates later in spring.

The maybe part comes with Maryland. Until very recently Maryland was listed in some sources as a state that would host Brood XIV cicadas in Washington and Allegheny Counties. There are several historical accounts of Brood XIV cicadas emerging in these counties dating back to the 1900s and 1940s. In 2008 along the Potomac River near Hancock, Maryland a localized ensemble of periodical cicadas was observed. Whether these were Brood XIV cicadas or not remains a mystery. Cicada researchers suggest that these may be stragglers from Brood X, time travelers that emerged four years behind the massive emergence of their brood-mates in 2021. This Bug Guy hopes that periodical cicadas are hanging on in Washington and Allegheny Counties. He plans to spend a lot of time wandering the C & O canal this spring and summer to catch a glimpse of Brood XIV or maybe the stragglers of Brood X. 

So, if you are concerned that periodical cicadas may not show this spring, put your fears to rest. In addition to Virginia, periodical cicadas will appear in parts of Georgia, Indiana, Kentucky, Massachusetts, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, and West Virginia. For the rest of us mostly east of the Mississippi, well, we will have to wait for another time.

We will explore much more about these remarkable creatures in upcoming episodes.

Acknowledgements

Bug of the Week thanks Gaye Williams for providing the inspiration for this episode. Many thanks to Gene Kritsky and John Cooley for sharing their data, thoughts, and information about these marvelous creatures. Special thanks to Dan and the Cicada Mania website for providing one stop shopping for cicada information. Thanks also to Dr. Shrewsbury for some nice camera work.  

Jaws of the jungle: Leafcutter ants and Army ants

 

Tales are told of the Mayans using ant soldiers to close wounds. Where these the sickle-shaped jaws of army ants or the powerful jaws of leafcutter ants?

 

Yeah, I know, a corny little play on words from George of the Jungle, that funny old 1960s animated series by Jay Ward and Bill Scott which was later made into a full-length motion picture starring Brendon Fraser in 1997.  Well, this week let’s return to the jungles of Belize where we recently visited stingless bees, sassy assassin bugs, red rump tarantulas, headlamp beetles, and incredibly fast whip spiders. Deep in the rainforest and sometimes encroaching on humans live a pair of remarkable ants with truly amazing jaws.

We discovered that the jaws of a leafcutter ant could surely open a wound.

A short hike into the Maya Mountains brought us into contact with a large colony of leafcutter ants.  Leafcutters have been termed a superorganism of the tropical rainforest, creatures with social structure and specialized roles that, as individuals, cooperate and contribute to the success and survival of their colony. It has been said that on planet earth only two creatures cultivate crops: humans and leafcutter ants. Night and day, members of the worker caste search for nutritious leaves on trees, vines, and shrubs. When scouts find a suitable food source, they direct other workers to the bounty by releasing trail-marking chemicals called pheromones. The amazing jaws of major workers clip small sections of leaves and flowers and carry them to the ground, where they join a rambunctious procession of nest mates. In this parade, intermediate sized workers busily transport leaf sections while smaller workers sometimes hitchhike on leaves and help defend their sisters from marauding predators and parasitic flies. Nearby, large imposing soldiers defend their sisters and the colony with powerful jaws. As leafcutters remove foliage from a tree, the parade of ants may extend for distances of more than 200 yards as workers carry leafy cargo back to a subterranean nest.

Leaves can look like this after a visit from leafcutter ants.

A leafcutter nest is a marvelous structure that may contain several million ants and occupy 600 square meters of forest floor. Sophisticated ventilation systems cool the bustling nest and allow carbon dioxide to escape while drawing in oxygen. Once inside the nest, leaves are delivered to other workers that take the leaf sections and clip them into ever smaller fragments. These fragments are carefully inserted into a garden of living fungus maintained by the ants. Leaves serve as a substrate for fungi, which is harvested as the source of food for the entire ant colony. The fungus garden is meticulously tended by workers. Destructive alien fungi are detected and removed. Secretions produced by the queen and workers facilitate the growth of the cultivated fungus. Fungal strands produce specialized structures called gongylidia. Gongylidia are fed to the developing larvae and distributed throughout the colony to feed workers and the queen. To support their enormous colonies, leafcutters remove vast amounts of vegetation each day. It is estimated that large colonies may remove more than 500 dry weight pounds of vegetation annually.

With a work force like this, it’s little wonder that some rainforest trees disappear overnight as leafcutter ants take foliage back to their amazing subterranean fungus gardens.

Sickle-shaped jaws of the army ant soldier compressed the skin and likely could act as sutures.

Another superorganism of the rainforest is the fierce army ant, arguably the most rapacious insect predator in the jungle. On a mountainside in the Cockscomb range of the Maya Mountains, we encountered a streaming column of army ants. This bustling brigade was only a small portion of a pillaging horde hunting food in one small corner of the forest. Single colonies of army ants contain hundreds of thousands to more than a million workers capable of capturing and eating thousands of assorted arthropods each day. The column consisted of large and small workers busily transporting food to a temporary food cache or colony site called a bivouac. In lesser numbers within and alongside the column were imposing soldiers. These grotesque giants sported huge, sickle-shaped jaws used to defend workers and colony from attack. At the raiding end of the ant column, a chaotic melee of murder and mayhem ensued as swarms of stinging and biting workers captured other arthropods, primarily insects and spiders. Other unfortunate small animals that fail to escape the approaching horde may also succumb. After subduing victims, workers dismember their prey and transport them in large and small pieces back to a food cache or bivouac to feed developing larval ants, their attendants, and the hungry queen.

Army ants sometimes make their bivouac in unusual places which can cause a bit of panic for someone using an outhouse in the rainforest.

The bivouac is usually in a protected location beneath a log or between the buttress roots of a large tree. It is formed by thousands of ants linked leg to leg in a protective living cover for the queen and young. However, army ants may set up bivouacs in man-made structures. I have witnessed this event firsthand on a study abroad where army ants raided a research station and established a bivouac in an outhouse. This provided quite a surprise when a sleepy student undertook a nighttime visit to the privy. The life of army ant colonies is characterized by two distinct phases. When the colony is in the nomadic phase, workers hunt by day and bring food back to the colony, but they stop carrying food to the bivouac as night approaches. Bivouacs are relocated periodically when excited workers transport food and ant larvae away from an old bivouac to a new one along one of the outward leading trails. As the old bivouac disintegrates, the queen and her entourage follow a chemical trail through the forest and establish a new bivouac at a different location. The regular relocation of the bivouac in the nomadic phase enables legions of workers to pillage untapped areas of the forest for food each day. Several times a year, the colony enters a stationary phase. During this phase, the colony hunkers down in one location for several weeks. Larvae begin to pupate and the queen lays as many as 30,000 eggs each day. During the stationary phase, raids continue but are less frequent and intense. Army ants change locations of their jungle raids regularly. Foraging in different areas ensures that new victims will be found, and also allows future prey to repopulate recently searched areas. Over the span of a few weeks, thousands of eggs hatch and hungry young larvae place enormous demands for food on the colony. By now, ants produced during the previous stationary phase have completed development and matured into new workers. With thousands of new workers to forage and the demand for food high, the colony resumes its nomadic phase and it’s time for many small insects and other animals to run for their lives or die.

In the Belizean rainforest enormous leafcutter ants use their sharp jaws to slice sections of leaves to fuel their fungus gardens back at the colony. On the rainforest floor raiding columns of fierce army ants capture small insects to feed their young. Large soldiers with sickle-shaped jaws help to dismember prey like this hapless grasshopper. Can the jaws on a leafcutter close a wound? Nope, but they surely can open one. Can the sickle-like jaws of the army ant be used to close a wound as told in folklore? Probably so. These are but two of the fascinating jaws of the jungle.

Circling back to “jaws of the jungle” brings us to my attempt to reconcile a scene from Mel Gibson’s 2006 film Apocalypto. The scene in question features a Mayan mother who sutures her child’s leg wound using ants. The YouTube clip for this scene is entitled “Apocalypto - Using army ants as sutures”, and the video pretty clearly shows leafcutter ant soldiers being applied to the child’s leg. With both leafcutters and army ants on hand in the tropical rainforest, how could I resist the chance to see which one could really close a wound? First, I applied a large leafcutter ant to my thumb. It’s sharp jaws neatly sliced my skin, opening a slightly bloody but memorable wound. On another occasion, I repeated the experiment this time with a large army ant soldier. It’s long, powerful sickle-shaped jaws pierced my finger, clamped together, and neatly compressed my skin. These jaws of the jungle left no doubt of their ability to close a wound. So, the take home for me is this: Jaws of the leafcutter ant open a wound. Jaws of the army ant close a wound. The yin and yang of jaws of the jungle.

Acknowledgements

We thank Drs. Dan Gruner and Paula Shrewsbury, the hearty crew of BSCI 339M: Tropical Biology and Mayan Culture, and our fearless guides for providing the inspiration for this episode. The wonderful book "The Ants" by Bert Hölldobler and Edward O. Wilson, “The Insect Societies" by Edward O. Wilson, and the interesting article "Army Ants: A Collective Intelligence" by Nigel Franks, were used as references for this episode.

Wicked spines and long legs spell trouble at night for creatures in the rainforest: Whip spider, Paraphrynus spp.

 

Once the spines of the whip spider get you, there is no escape.

 

The whips of the whip spider are its incredibly long front legs used to locate prey, mates, and danger.

Last week on a nighttime adventure in the rainforest, we a met the very cool headlight beetle illuminating its journey through the rainforest. But this was not the only encounter with a spooky denizen of the dark. Resting on the trunk of a tree was a really mysterious arachnid called the whip spider, a.k.a. tailless whip scorpion. While not really a scorpion or a spider, this bizarre creature is a member of an arachnid clan known as Amblypygi. Whereas spiders and true scorpions amble about on four pairs of legs, whip spiders use just three pairs for nocturnal strolls. The fourth pair of legs, found at the front of the creature, is extraordinarily long and thin and loaded with sensory structures to detect odors and objects including mates, offspring, and prey. These so called “whips” can be three to six times the length of the body and give the whip spider its common name. Whips can move in an almost  complete circle around the creature and are very useful for detecting objects ahead, behind, above, and to the sides in a world of darkness.

A walk in the tropical rainforest at night is an awesome adventure filled with encounters with fearsome creatures. Resting on the trunk of a tree we discovered a whip spider just waiting for some hapless victim to stroll by. Super long front legs detect prey and wicked spines on the pedipalps guarantee there is no escape. A slight movement by the camera guy caused the whip spider to jet out of sight. Even slowed by 85%, the whip spider vanished almost too quickly to see.

Just in front of the whip-like legs is a pair of terrifying hinged appendages known as pedipalps. This “sit and wait” predator uses its pedipalps to capture prey in much the same fashion as a praying mantis uses its spiny forelegs to grab its victims. As a tasty morsel enters range, a rapid strike of the pedipalps ensnares the prey in comb-like spines. Usual meals include crickets, cockroaches, spiders and moths, but small lizards and even fish are known to be eaten by these clever predators. Once captured, the victim is pulverized by two grinding jaws called chelicerae. Digestive enzymes added to the pulpy mass enable the whip spider to ingest the liquefied meal.

Who knows what the leaflike expansions are for on the hind legs of this tiny whip spider?

As frightening as whip spiders appear, they are truly harmless to humans. In fact, some species have several admirable and somewhat endearing behaviors. One such behavior is a fine sense of direction. While wandering about the rainforest at night it is easy to get lost. On more than one occasion, hapless adventurers have disappeared into a ravine while searching for a trail in dense tropical vegetation. Not so the whip spider! Research has shown that some whip spiders can find their way home after being moved more than 30 feet away from their refuge, all of this without Google Maps.

For any mothers who might be reading this episode, think about the calories you burned lugging youngsters about when they wanted to be picked-up. Whip spiders lay from 10 to 90 eggs at a time. Mother whip spiders typically carry their young on their backs for several weeks after offspring hatch from eggs. In captivity, females of the Floridian whip spider, Phrynus marginemaculatus, continue to interact with their offspring for several months after the babes have departed from their mother’s back. Mothers were observed to move between small clusters of young ones. Females and offspring frequently engaged in gentle mutual stroking with their whip-like legs. How often these fascinating behaviors happen in the wild remains to be seen. The message conveyed by the mutual stroking is known only to the whip spider and her young, but on a dark night in the rainforest a gentle touch from mom could be a comforting signal, even to a whip scorpion.      

Watch as the whip spider senses the approaching danger of a giant finger and rockets out of harm’s way. At one tenth of normal speed, see how the whip-leg of the arachnid reaches back to examine the intruder’s finger before turning on the speed to escape.

 References    

On the steps of El Castello at the Mayan ruin of Xunantunich, students discover Mayan history and look forward to nighttime adventures in a tropical rainforest where amazing insects and arachnids abound.

Bug of the Week gives special thanks to Drs. Dan Gruner and Paula Shrewsbury, the hearty crew of BSCI 339M: Tropical Biology and Maya Culture, and the fearless guides at the Toucan Ridge Ecology and Education Center and  Cockscomb Wildlife Sanctuary who were the inspiration for this episode. Kenneth J. Chapin and Eileen A. Hebets’ treatise, “The behavioral ecology of amblypygids”, and the wonderful article “Social behavior in Amblypygids, and a reassessment of arachnid social patterns” by Linda Rayor and Lisa Anne Taylor, were used as references for this episode.