Written by Collin McMichael, Education Coordinator
Bug of the Month: After Dark was a smashing success, but instead of continuing the gross-out-fest that this column has become I’ve decided a new year means a new theme! And what’s more in keeping with the bright and shining future we are confidently striving for than the erroneously named Lanternfly?
The lanternfly is a perfect example of “What the heck were those early naturalists thinking?” as it is neither light emitting nor a Dipteran. Lanternflies belong to the insect order Hemiptera, meaning they are true bugs, not flies. They are a type of bug called a “planthopper” due to their herbivorous and rather bouncy nature, but more specifically they are planthoppers in the family Fulgoridae. Fulgorids are known for their intense wing venation and unusually bright colors. Several genera have elongated portions of their forehead, portions that the previously mentioned early naturalists were just absolutely sure had to light up. It turns out they don’t.
The mistaken supposition that these snooty bugs just had to be luminous can be traced back to a German naturalist and artist named Maria Sibylla Merian. Ms. Merian was, and still is, considered a pioneer in the field of entomology, pushing it ahead much farther than one would expect from the precious few decades she dedicated to its study. Her 1705 treatise and full-color plates of the insects of Surinam is still printed today with the vast majority of insects in it being identifiable to species solely from her depictions. Despite her illustrative career, her flawed belief in the bioluminescence of these bugs is one of her most lasting marks on entomology. It was solidified by Carl Linnaeus, the father of Latin names, who used her comments on Fulgorids when devising some of their specific epithets, namely lanternaria, phosphorea, and candelaria.
Bug based mythology aside, lanternflies themselves are quite interesting in their own right. Their behaviors are not terribly impressive, but those unusually bright colors are. Their wings are often spotted, striped, or display distinct eyes to ward off would-be predators. Eyespots may be rather self-explanatory for dissuading consumption; consider for a moment the last time you were shocked to see eyes peering back at you when least expected. Bright colors, on the other hand, might make the processed-food-obsessed modern human more inclined towards the meal. This would be a mistake.
Bright colors in the natural world can be used for several things. Solid colors are generally a lure-type intraspecific signal, much like red fruits attract birds or blue flowers attract insects. Patterns with contrasting colors are the exact opposite, warning anyone to stay well away, much like a coral snake or yellow jacket advertise their venom. These are not rules, per se, as many animals attempt to hijack the system to get what they want. Non-threatening individuals may display threatening colors in the hopes that predators have already experienced the adverse effects that usually track with them. Similarly, lure-type colors can be used to trick animals into danger. Lanternflies belong to the group of animals attempting to dissuade would be attackers by advertising their disgusting flavor. This type of coloration is known as aposematic coloration, and in insects, it is usually due to the critter sequestering nasty plant metabolites in their tissues so predators find them distasteful.
Some lanternflies actually adopt bright colors when they switch to toxic hostplants from something without nasty metabolites. Lycorma delicatula, the spotted lanternfly, is a well-studied example of this phenomenon. These little beasties usually feed on a rather interesting assortment of plants belonging to the grapes, pines, stone fruits, and apples. When they do feed on these plants, they are somewhat drab in coloration favoring blacks and muted earth tones. However, when they are able to find their favorite food, a tree of heaven, or Alianthus altissima, they chow down, sequester the toxic chemicals present in that plants sap into their own tissues, and assume a new hot-rod paint style complete with bright red hindwings to flash as a threat display.
Interestingly, both trees of heaven and the spotted lanternfly are non-native, invasive species. Both originally came from Asia. The tree of heaven was introduced to the U.S. as early as 1784 and makes a titular appearance in the book A Tree Grows in Brooklyn. Unfortunately for many, it turns out this tree is especially good at colonizing disturbed sites, reproducing quickly, suppressing other plant growth through allelopathy, and, just to add insult to injury, smelling absolutely awful. The spotted lanternfly is a much more recent addition making its first appearance in America as late as 2012 when it showed up in Pennsylvania and survived one of the harshest winters in recent memory. Since then it has spread to New York, New Jersey, and Virginia, mostly through human transport as this planthopper likes to hop more than fly.
The complicated case of these two invasions becomes more ensnared with one another when you realize it is the presence of the tree of heaven that has allowed the lanternfly to do so well. Often, bugs are introduced to control pest plants; however, these bugs are almost always not absurd generalists who can’t even whittle down their host choices to either gymnosperm or angiosperm. Being a generalist means the lanternfly will do little to suppress tree of heaven populations. Instead, the tree of heaven populations will bolster the spotted lanternfly invasion by supplying them with a means to further escape the natural enemies so few and far between in their new home. If the tree of heaven were not present, there might have been enough hungry mouths to fight off the lanternflies for good.
Instead, it is the lanternfly’s hungry mouth we get to contend with. These bugs, as invasive species, can show up in large numbers overwhelming a trees ability to fight them off. Once present on a tree, they suck on phloem sap much like an aphid. Also much like an aphid, this phloem sap shoots right through them since its mostly water. This oh-so-pleasantly-named excretion is called honeydew, instead of what it really is: bug diarrhea.
Honeydew first clings to the rump of the lanternfly. This can attract ants, bees, and wasps to the tree. Once more honeydew is excreted, it drops off either landing on a leaf below or the ground, attracting more ants and bees and wasps and anything else that likes sugar water. Being sugar water, this collection of excrement tends to grow fungus prolifically, often forming dense mats below infected trees. This fungus is mostly unsightly, but when growing on leaves it can inhibit photosynthesis. Most of the damage to the tree comes from a loss of turgor pressure in their phloem tissue, meaning they are essentially exsanguinated.
While Virginia may seem quite far away, the interstate transportation of plants and materials may bring the spotted lanternfly to Texas sooner than anyone would hope. When it gets here, you can be sure you will hear about it as stone fruit and grapes are important local crops. Furthermore, the fragile, remnant ecosystem lovingly called Lost Pines could be lost for good if these pine sucking buggos get their way.
