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Science
Volume 40 Issue 9 • July 1-7, 2010
now in our 40th season

Bugs & Beetles

This time of year there are a plethora of bugs enjoying the plants in bloom, advantageous tidal cycles, high humidity and warm temperatures. Most of the time we are bugged by the bugs; heck, we appropriated the word “bug” to mean literally “to bother.”  Whether it is the green head flies, the mosquitoes, or the gnats, something is bound to be chewing on you. I’ve written about many other bugs species in the past few years and those articles can be found in the Yesterday Island online archives.  Make sure to catch up on the island essays, reviews, cooking and historical articles while you are there. This week I wanted to highlight some of the many amazing, beautiful, and downright weird bugs and insects hanging around. All of these creatures can be found on island this time of year. Once you see one, you’ll see dozens, in the same way as that Volkswagen beetle you bought in the 80s. I saw the following insects on a nature walk along the dirt road to Altar Rock.

But first we should discuss “What is a bug??”  Often people use the word bug interchangeably to mean an insect. An insect is a small arthropod animal of the class Insecta, having an adult stage characterized by three pairs of legs and a body segmented into head, thorax, and abdomen and usually having two pairs of wings. Insects include the flies, crickets, mosquitoes, beetles, butterflies, and bees. Although the term bug is often used generically to mean any insect, the scientific definition for a “bug” is an insect of the order Hemiptera, known as the "true bugs."  They belong to the phylum, Arthropoda which includes all invertebrate animals having an exoskeleton (external skeleton), a segmented body, and jointed appendages. The word arthopoda comes from the Greek “arthron” for "joint," and “podos” or "foot," which together mean "jointed feet." The phylum Arthropoda includes the insects, arachnids, crustaceans, and many other creatures with an estimated total of over a million described species, making up more than 80% of all species.

Bugs and Beetles

The first creature we encountered on our walk, settled into the joints of a tree beside the parking lot right next to Polpis road was a spittle bug hiding in its bubbly little foam home. Other than looking somewhat gross, spittle bugs do very little damage to a plant. They do suck some of the sap from the plant, but rarely enough to harm the plant. The foam serves mostly to hide the adult and immature spittle bugs and to keep the little guy from drying out in the sun. The “spit” is also known by the amusing and memorable names of cuckoo spit, frog spit, or snake spit.  The photo by Kurt Kulac shows what they look like hiding in the foam nest.  Nymphs resemble adults but are smaller and wingless.  The color on nymphs can vary from yellow to white to orange, but the eyes are always red. The spittle is a mixture of watery waste; air, which is blown through abdominal openings (okay, basically its butt) to make bubbles (a fun party trick); and a glandular secretion. More than one nymph may be found in a spittle mass. After the nymph molts for the final time, the resulting adult insect leaves the mass of "spittle" and moves about actively. Spittlebug nymphs wander away from their spittle masses and either start new ones, or enter those of other nymphs (hello!). Aphrophora nymphs hold the record size for a single spittle mass over a foot long containing about 100 individuals (party)!  The Spittle Bug belongs to the order of Hemiptera (True Bugs, Cicadas, Hoppers, Aphids and Allies), suborder Auchenorrhyncha  Family – Cercopidae, which is the froghoppers family (they look a little like squat frogs) and there are either 15 or 67 species depending on who you ask (http://bugguide.net/node/view/145).

It was long thought that the flea was the highest jumper in the insect world, but it turns out that the spit bug is the all-time winner.  British scientists discovered (www.usatoday.com/news/health/2003-07-30-spittle-bug-jumper_x.htm) using a high speed camera, that the spit bug can leap two feet into the air, accelerating to 400 times the force of gravity versus 135 times the average acceleration of a flea. That is the equivalent of “g” (gravity) forces/acceleration experienced while being shot out of a supersonic cannon.

Sometimes when we think of bugs we may be also thinking of one of the many lumbering beetles we see on the ground. The English etymology for the word “beetle” is "the little biter," derived ultimately from Old English bitela, from bītan, "to bite."  Beetles are the largest order in the animal kingdom, and with more than 350,000 described species worldwide, represent about 40% of known insects. Some scientists believe there may be as many as 1 million species! Beetles are classified in the order Coleoptera which is derived from the Greek “koleon” meaning "sheath" and “ptera” meaning "wings."  Aristotle called beetles “koleopteros” to refer to the front wings modified to protect the membranous hind wings (elytra).

While heading for Altar Rock, our eyes often glimpsed flashes of brilliant metallic green scurrying around on the dirt roads that are the tell-tale sign of a tiger beetle, most likely the six spotted tiger beetle (Cicindela sexguttata).  Tiger beetles often have large bulging eyes, long, slender legs and large curved mandibles. All are predatory, both as adults and as larvae. This tiger beetle is an active predator and can frequently be found hunting along footpaths and walkways through deciduous or mixed woodlands.  Since the adults overwinter in their original pupal burrows, they are some of the earliest flying insects out and about each spring. You can sneak up on them if you move slowly and approach from a low angle - they'll fly off if you blot out large areas of sky. These tiger beetles are different from the three species of special concern that might be found on Nantucket, the purple tiger beetle (Cicindela purpurea) seen on our beaches, the bank tiger beetle (Cicindela limbalis) and the extremely rare (last seen in 1923), twelve-spotted Tiger Beetle(Cicindela duodecimguttata). Tiger beetles have been considered as good indicator species and have been used in ecological studies on biodiversity.

Of course, one of our most famous local “bugs” is the carrion eating “little undertaker” the burying beetle. The American Burying beetle, Nicrophorus americanus, is one of 31 North American species in the family Silphidae, the carrion beetles. It is the largest carrion feeding insect in North America, measuring up to 3 cm. For many years on Nantucket, scientists from Boston University, the U.S. Fish and Wildlife Service, and the Roger Williams Park Zoo with help from on island scientists have been participating in a very successful reintroduction program to help shore up the dwindling population (www.rogerwilliamsparkzoo.org/conservation/beetlesspupdate.cfm).  Read more about this fascinating creature and the efforts to protect in this online edition from last year’s June 18-24th edition of this publication at www.yesterdaysisland.com/archives/events/7a.php.

Although certainly an insect, not technically a “bug,” I can’t help but mention some of our moth friends seen in the middle moors.  Draped in the blueberry and huckleberry shrubs we saw these dangling bits of yellowish caterpillar known as the larval form of the chain dotted or chain spotted geometers moth (Cingilia catenaria (Drury).  These are the quintessential “inch worms”.  They move by extending the front of the body as far forward as possible, then bringing the rear  of the body up to meet it; this is how they have gotten the name  "inchworm," “span worm,” or "measuring worm." In addition to their somewhat comical ambulation is the fact that they will hang straight down from a stem.  According to the Natural Heritage and Endangered Species Program in Massachusetts (www.mass.gov/dfwele/dfw/nhesp/species_info/ nhfacts/cingilia_catenaria.pdf), the Chain dot geometer is also a species of special concern.  The larvae feed on a wide variety of trees and shrubs, and are often conspicuously abundant in peatlands.  The scientific literature say that the species prefers blueberries, huckleberries, and small trees growing in pastures or cut areas, which explains why we see them in areas on island in which land management practices such as prescribed burns and mowing have been used.

From an incredibly useful online guide to bugs “Bugguide.net” is the etymology of the moth genus name of “cingilia” from the Latin "cingula" for “a girdle”; maybe reference to the dark dots that girdle the perimeter of the wings of the adult moth and “catenaria”, derived from the Latin "catenarius" - from "catena" (a chain); a reference to the "chain" of black dots on the wings of the adult and/or the sides of the larva, and the origin of the common name Chain-dotted (or Chainspotted) Geometer. To see lots of chain dot geometer pictures go to http://bugguide.net/ node/view/60. The adults are very pretty. On our walk, we were lucky enough to spot a state-listed Barrens Buck Moth (Hemiluca maia), feeding on its traditional scrub oak treat.  We also saw several of the white marked tussock moth that I wrote about previously in my “strange and unusual creatures” article (find it at www.yesterdaysisland.com/archives/science/16.php).

My friend, Dr. Jenn Forman Orth, runs the super fun website “Bug of the day” which allows one to sign up for a daily bug picture (http://www.flickr.com/photos/urtica/collections/72157600071443705/. I highly recommend her daily bug service, not only do you learn to appreciate what is hanging out in your yard, but you also almost always manage to have a smile when you see her photography. To learn more about other rare and endangered insects and plants found on Nantucket, go to www.mass.gov/dfwele/dfw/nhesp/species_info/town_lists/town_n.htm

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