From the Bug of the Week mailbag – Rose of Sharon on the menu for the hibiscus scentless plant bug, Niesthrea louisianica

 

An adult hibiscus scentless plant bug hiding beneath a flower bud glams for the paparazzi.

 

Harlequin colors of orange, black, and white are definitely “in” this pre-Halloween season. Just ask nymphs of pretty hibiscus scentless plant bugs as they the suck fluids from buds of Rose of Sharon. Image credit: Sonia Smith

Last week a super sleuthing Master Gardener discovered a highly suspicious orange, black, and white bug on her thirsty Rose of Sharon. Fearing a visit from the dreaded spotted lanternfly she hit the web-o-sphere and correctly identified the critter as a scentless plant bug. Nice detective work. My first encounter with this fetching rascal happened on a trip to a home improvement store, where I discovered a forlorn collection of Rose of Sharon shrubs desperately hoping someone would buy them before they were relegated to the dumpster to make room for a sprouting forest of plastic Christmas trees. One look at blossoms that had since gone to seed revealed hordes of magnificent scentless plant bugs decked out in harlequin costumes of orange, black, and white. With all the recent fuss about invasive bugs like the spotted lanternfly and brown marmorated stink bug, my angst twisted on the possibility that this was yet another case of a noxious invader arriving on our shores with a shipment of exotic plants. A quick look at the labels on the Rose of Sharon revealed that these plants were homegrown. A little poking around on the internet confirmed this to be a native bug with some redeeming qualities rather than a nocent new pest. Whew, what a relief!  

Although this bugger was new to my eyes, Niesthrea louisianica is long known to occur in North America from New York to Florida and west to California. This curious sucker is a gourmand for plants in the mallow family including cotton, Chinese lantern, okra, and Rose of Sharon. Like its cousins, the boxelder bug and red-shouldered bug that we met in previous episodes, Niesthrea has sucking mouthparts used to probe vegetation and seeds and extract liquefied nutrients. Unlike stink bugs and boxelder bugs that flock to houses to overwinter, Niesthrea finds a protected refuge outdoors beneath leaves and duff near its host plants. In spring, adults return to plants, begin feeding on foliage, and after mating, lay eggs in clusters of one to three dozen on the foliage or developing fruit of their host. After about a week, eggs hatch and tiny nymphs begin to feed. The plant bug requires little more than a month to complete a generation in summertime, and in southern states several generations occur each year.

During the growing season when flower buds abound, scentless plant bugs complete several generations on members of the mallow family. In the month of September, winged adults like the one on the left mill about with pretty orange and black nymphs. Later, when only dry pods remain, adults search for seeds to suck on, spend a little time hanging out with the gang, and work on looking sharp with some careful grooming of legs, wings, and derrière.

Rose of Sharon is a favored pollen source for many pollinators.

Bug of the Week has visited several exotic insects that attack our native plants after arriving in the US. However, beautiful Niesthrea louisianica turns the table and demonstrates how plant-feeding bugs sometimes become our allies when the plants on their menu are weeds. Throughout the corn and soybean growing regions of the US, an aggressive exotic weed called velvetleaf competes with our crops for nutrients and water. Velvetleaf is a member of the mallow family and thereby qualifies as a dinner item for hungry Niesthrea. By attacking the pods of velvetleaf and killing developing seeds inside, this small bug plays an important role in reducing the numbers of noxious velvetleaf weeds in many parts of the country. In one study, more than 80,000 Niesthrea lousianica were raised and released in several Midwestern states. Near the points of release, Niesthrea made a serious dent in the viability of velvetleaf seeds. Score one for the hometown bug.

Acknowledgements

Bug of the Week thanks Sonia Smith for inspiring this week’s episode and providing the nice image of scentless plant bugs. Two fascinating references, “Life History of Niesthrea louisianica (Hemiptera: Rhopalidae) on Rose of Sharon in North Carolina” by Al Wheeler and “Inundative biological control of velvetleaf, Abutilon theophrasti [Malvaceae] with Niesthrea louisianica (Hem.: Rhopalidae) by N. R. Spencer, were used as references for this episode.

Dragonfly meets spider, spider eats dragonfly: Seaside Dragonlet, Erythrodiplax Berenice, and daddy-long-legs, Pholcus spp.

 

Seaside Dragonlets spend much of their time perching on vegetation and are unique in their ability to breed in salty pools of water near the ocean.

 

Along the Atlantic coast from Nova Scotia to Florida a delightful small dragonfly called the Seaside Dragonlet makes saline pools its home. This small dragonfly is unique among its kin by virtue of the fact that it is the only member of the order Odonata capable of developing in a marine water source. That’s right, immature stages of other dragonflies live in the fresh water of streams, lakes, ponds, and swamps. Nymphs of the Seaside Dragonlet are able to survive in pools of water with salinities as high as 48%. Now that’s one salty brew.

A large pholcid spider takes advantage of the illuminated porch of a bayside home to construct its deadly web.

Unlike highly active dragonflies intent on staking out territories and actively defending them like ones we met in a previous episode, Seaside Dragonlets are described as lethargic and apparently show little interest in defending territories. Most of their time is spent in the leisurely activity of perching on vegetation with their head directed upwind toward the prevailing breeze. Scientists believe an upwind orientation may assist with lift-off when they decide to fly. On a recent visit to coastal Delaware, we were amazed by the vast number of Seaside Dragonlets in the landscape, where they perched on vegetation and blades of Spartina grasses at the edges of marshy pools. Little did the dragonlets know that humans had unintentionally designed a lethal trap for them in the form of marsh-side vacation homes. In a new development of beautiful homes, builders created covered porticos at the front entry of each house. These small porches were illuminated at night by brilliant lights that attracted a wide variety of arthropods. One group of opportunistic arthropods is spiders, predators with a fondness for building webs in nooks and corners of buildings. In past episodes we met pholcid spiders known as daddy-long-legs, web builders along walls and in corners of rooms inside homes. In the benign corners of the illuminated porch of one vacation home, pholcid spiders discovered excellent hunting grounds and set up shop to capture prey. During summertime, Seaside Dragonlets appear to be a staple in their diet.

On a shrub in the front lawn of a bayside home, Seaside Dragonlets perch facing an onshore breeze. In an upper corner of an illuminated porch, the gossamer web of a pholcid spider has snared a dragonlet. Despite attempts to free itself, by the following morning after a lethal encounter with the spider, it has joined other dragonflies and a crane fly in daddy-long-leg’s web of doom.

Snared by the web of a pholcid spider, a Seaside Dragonlet faces impending doom courtesy of lethal fangs.

Near one such home, dozens of Seaside Dragonlets perched on ornamental shrubs and lazily cruised the landscape. In the corner of the front entryway of this home, several dragonlets and other hapless six-leggers were tangled in the loose web of a rather large pholcid spider. As I entered the home one evening, a newly snared dragonlet struggled to break free of the sticky strands of the spider’s web. By morning, its struggles had ended and the dragonlet joined a macabre tableau of ill-fated prey kissed by the lethal fangs of the spider. As you watch the video, you will see a click beetle and crane fly that also succumbed to the spider’s bite. In addition to some dragonflies, several species of beetles, flies, moths, and other insects are attracted to porch lights. These prey items may catch the attention of hungry dragonflies. In an attempt to capture prey of their own, perhaps Seaside Dragonlets unwittingly become snared in the trap set by an even more fearful predator, the daddy-long-leg spider. There is a strange irony to see a dragonfly, an active ariel predator, dispatched by the clever silken contrivance of the patient spider, abetted by lights and corners provided by humans.            

Acknowledgements

Bug of the Week thanks Drs. William Lamp and Jeffery Shultz for providing identifications of the dragonfly and spider, respectively. The following articles were used to prepare this episode: “Observations of dragonflies visiting lights at night” by F. Kon Hong-Qiang, “The Behavior of the Seaside Dragonlet, Erythrodiplax berenice (Odonata: Libellulidae), in a Maine Salt Marsh” by W. Herbert Wilson, Jr., and “Arizona dragonflies” by Ann Cooper.