It’s hard for us to wrap our minds around how populations of an organism that occurs by the millions (like the horseshoe crab, of recent BOTW fame) could be threatened. And yet.
In the early 1990s, an estimated 400 million Monarch butterflies (by some accounts, 700 million) overwintered in the mountains west of Mexico City. By 2010, that number had dropped, but it stabilized at around 100 million, though only 33 million were found in the winter of 2013-14. This year’s population is estimated at 93 million; the biomass of Monarchs went, according to the Center for Biological Diversity, from covering 39 football fields to covering about one. In the mid-1990’s, overwintering butterflies were found on about 44 mountainous acres; in 2013-14 on less than two acres; and this winter, on about 7.5 acres, down about 15% from last year.
The “Eastern Monarchs” that winter in the oyamel fir forests represent the entire migratory population this side of the Rockies. Pacific monarchs, whose numbers are also in steep decline, migrate along the coast to California, and there are non-migratory populations along the Gulf Coast and South Texas.
Still, 100 million butterflies is a lot of butterflies, right? Not when you consider the impossibility of what they do, which is to undertake a 2,000-plus mile migration. Monarchs weigh about one-half of a gram each, which means that a Quarter pounder is equivalent to about 225 Monarchs (the BugLady was told there would be no math). They face the physical dangers of a trip that takes them from as far north as Canada all the way to Central Mexico, where they spend months in resting mode before (right about now) perking up and meandering north. The same individuals that left Wisconsin to begin the return trip, but their offspring’s offspring tag home here in May.
They face predators, cars, habitat loss, agricultural pesticides, and the shifting seasonal temperatures and increasingly severe weather events precipitated by Global Climate Change (aka Global Weirdness. There were three hurricanes and two tropical storms at the start of the 2017 fall migration period http://monarchwatch.org/blog/2017/09/15/forgotten-victims-of-harvey-the-pollinators/). The fall migration of 2017 along the Atlantic Coast was late, with some butterflies lingering into late October and even early November, lulled by unseasonably warm weather, the late migrants left susceptible to storms and freezes. For a rundown on Monarch mortality factors, see “The State of the Monarch,” an August 2015 BOTW, at http://uwm.edu/field-station/the-state-of-the-monarch/). The only cushion against mortality factors like that is a huge population.
The US Fish and Wildlife Service tells us that “nearly a billion monarchs have vanished from the overwintering sites since 1990,” and according to a recent article in USA Today, “A 2016 study by the U.S. Geological Survey concluded that because of ongoing low population levels, there is an 11% to 57% risk that the eastern monarch migration could collapse within the next 20 years.”
Not on our watch!
Milkweed has declined dramatically in agricultural areas in the Midwest, where the Monarch’s population strongholds are (the “Milkweed Limitation Hypothesis”). Planting milkweed for caterpillars – and other nectar-bearing wildflowers for adults – as a part of grassland habitat restoration is a good start and it’s pretty and it can’t hurt. Chip Taylor, of Monarch Watch, goes further, saying that “we need a comprehensive plan on how to manage the fragmented edges and marginal areas created by development and agriculture since it is these edges that support monarchs, many of our pollinators, and the many forms of wildlife that are sustained by the seeds, fruits, nuts, berries, and foliage that result from pollination.” Late-blooming, nectar-bearing flowers fuel the fall migration and allow Monarchs to gain the fat reserves that will carry them through the winter.
Finally, the Monarch is under consideration for Endangered Species protection, a decision that will be made by June 2019 (https://www.fws.gov/savethemonarch/SSA.html). It needs to be on that list so that legal protections will apply
[Mildly political aside: And, of course, there needs to be an effective Endangered Species Act https://news.nationalgeographic.com/2017/05/endangered_speciesact/. Wonder what would happen if every school child drew pictures of Monarchs and sent them to their Congress-people and to the Fish and Wildlife Service?]
Ever since the BugLady started her “Bugs in the News” sub-series, alert BugFans have been sending links to articles they’ve come across. Thanks, BugFans! Alas, to view a few of these, you have to wade through some ad content.
And, if you’re interested in other things with wings, try this (after yet another ad), mostly in the daylight: http://rowe.audubon.org/birds/crane-cam (you may have to hit Reload).
This episode has been adapted from the Spring, 2010 issue of the BogHaunter, the newsletter of the Friends of the Cedarburg Bog; it was written by the BugLady, wearing a different hat. Woodcocks were a big part of her childhood – their return to our brushy fields was celebrated each year. Thanks, Mom, thanks, Dad.
Coming soon, to a field near you!
American Woodcocks (Scolopax minor) are long-billed, big-eyed, short-legged, round-winged, Robin-sized birds. The Cornell University All about Birds website says “Their large heads, short necks, and short tails give them a bulbous look on the ground and in flight” (“bulbous?” Really?). Their brown-streaked plumage makes them impossible (for the BugLady) to spot on the ground – she once stood near two young birds for about five minutes until they couldn’t stand it anymore and departed, with wings whistling. Woodcocks are shorebirds that are not tied to the shoreline – upland game birds, the “Landlubbers” of the shorebird family. These odd-looking birds (apparently, hunting dogs find them odd-smelling, too) have many nicknames, like “timberdoodle” and “bog-sucker” and “night partridge.”
A woodcock is a bundle of adaptations. Their short wings make it easier for them to maneuver in the brushy fields, woody edges, wet meadows, and open woodlands that they call home, and the fact that they are able to fly slower than any other bird – 5 MPH – serves them well in those spots.
Most of their adaptations have to do with their feeding habits. That long bill allows a woodcock to extract earthworms and other invertebrates from deep in the moist soil. The tip of the bill is both flexible and sensitive and can be opened without opening the base. Worms are slippery little devils, and roughened surfaces on the tongue and upper bill help it to get a grip. And a good thing – a woodcock may eat its weight (about a half-pound) in worms daily. See http://www.ruffedgrousesociety.org/Woodcock-Facts#.Wp2XumrwbIU for a video of a woodcock foraging.
Several sources said that the woodcock’s typical rocking walk may produce vibrations that rouse earthworms into motion so that the woodcock can hear it (and yes – you’ll get some interesting hits if you Google “Woodcock walk like an Egyptian”).
Any animal that feeds with its head down runs the risk of becoming a meal while having a meal. Over time, woodcock eyes have migrated toward the top of their head. As a result, woodcocks have good vision both to the back and to the sides while they probe for worms (as opposed to a robin, which has eyes on each side of its skull and can’t see much to the fore or aft). Because their eyes have thus migrated, their brains are upside down.
But, they’re famous for something besides their looks.
Woodcocks make their presence known in early spring – often by mid-March – when males take to the air to perform their amazing “sky dance.” They begin around sunset and continue into the wee hours, especially if the moon is full – the BugLady has heard them in her field at 1:00 AM. Here’s how it goes. After calling from the ground for a while – a nasal sound described as a “peent” https://www.youtube.com/watch?v=4Owj52XhoxI – the male takes off. Specially-shaped wing feathers produce a twittering sound as he spirals into the air, sometimes more than 300 feet up. From high in the sky he zigzags back down, vocalizing a rich “chirp, chirp, chirp, chirp” sound.
Let Aldo Leopold tell it: “Up and up he goes, the spirals steeper and smaller, the twittering louder and louder, until the performer is only a speck in the sky. Then, without warning, he tumbles like a crippled plane, giving voice in a soft liquid warble that a March bluebird might envy. At a few feet from the ground he levels off and returns to his peenting ground, usually to the exact spot where the performance began, and there resumes his peenting.”
There, the theory goes, the awed female woodcock will find him. The dance is repeated at dawn.
The first sound on this audio is the chirping call of a descending bird https://www.allaboutbirds.org/guide/American_Woodcock/sounds, and if you listen, after he’s landed and is peenting, you can hear the faint “Whoop – Whoop” sound that apparently is a communication between two birds that are on the ground. More vocalizations can be heard in the “Sound and Calls” section at the bottom-right-hand corner of the first page http://www.audubon.org/field-guide/bird/american-woodcock.
Once she finds him, he struts and bows with outstretched wings. Females may make the acquaintance of several males and vice versa, but by the end of April, the show’s about over. Males will continue their sky dance into early May – even though most of their potentially appreciative audience is sitting on eggs. Hope springs eternal, and some females will join the dance even while they’re caring for young.
Woodcocks nest on the ground; females line a shallow depression with leaves and deposit (usually) four eggs in it. She will sit on them for about three weeks, often incubating during the final snowstorms of spring. The young are “precocial,” (think “precocious”) – unlike the blind and naked young of songbirds, woodcock nestlings are dried off and running around within hours of hatching, and although she continues to feed them for a week or so, the young are probing for food when they’re just three or four days old, and flying after two weeks. The male does no incubation or child care.
As ground-nesting birds, woodcocks are preyed on by dogs, cats, skunks, possums, and snakes. The BugLady once saw a woodcock fluttering across the grass-tops in a field, pursued by a raccoon; it may have been a female, leading the raccoon away from her nest.
Many birds undertake epic migrations, but as the ground chills and worms migrate vertically to escape the frost, woodcocks need only travel to the Southeastern and Gulf States, where unfrozen ground allows them access to food. Woodcocks migrate at night, at low altitudes, alone or in small groups, usually starting in October. The trip is unhurried, with the birds’ cruising along at about 25 MPH on these flights. They start the return trip in February.
Around the beginning of the 20th century, books were being cranked out by “nature-f
akers,” who romanticized and anthropomorphized the daily lives of the animals they wrote about. They wrote that a woodcock was able to set its own leg if one got broken – the proof being the crusted mud often seen on woodcocks’ legs.
Back in 2011, the BugLady wrote about a spectacular arthropod called the Horseshoe crab that pre-dates insects by maybe 100,000,000 years. Despite the fact that they occur by the millions, horseshoe crabs are facing dire threats to their populations, and the BugLady wondered if anything had changed since the original episode. New text, old text, and pictures of a 1 ½” long, translucent, infant horseshoe crab that washed up on Sanibel long ago, that the BugLady happened to have in her collection. Put your feet up – this takes some telling.
The BugLady had taken herself on a little road trip to the Delaware Bay, the home of the horseshoe crab. Because of their cute faces and their long and primitive lineage (they are called “living fossils”), horseshoe crabs grab our imaginations – they are one of those creatures whose appearance immediately transports us to ancient swamp forests and shallow inland seas.
Horseshoe crabs have, in the words of local news-people, a “Wisconsin Connection.” They are close relatives of our beloved State Fossil called the Trilobite, an ancient inhabitant of those inland seas.
The story of the Atlantic horseshoe crab stretches from the great extinctions of the Silurian Period to the unique threats of the 21st century. The operative question is whether an animal that has survived for almost a half-billion years will join its extinct trilobite ancestor under our watch.
They are shaped like horseshoes, but they’re not crabs. They are under the same big umbrella as crabs – phylum Arthropoda (“jointed limb”) – but horseshoe crabs headed out on a completely different limb of the family tree a very long time ago, and they’re more closely related to spiders and scorpions. They’re in the class Merostomata (“legs attached to the mouth”), in the order Xiphosura (“sword tail”), in the family Limulidae. There are four living horseshoe crab species in the world, three of which reside along the edges of Asia. The Atlantic horseshoe Crab (Limulus polyphemus) (“Limulus” means “askew,” and the BugLady trusts that BugFans recall who Polyphemus was) is found in shallow ocean edges with soft, mucky or sandy floors from Maine through the Gulf of Mexico.
The fact that horseshoe crabs can survive dramatic changes in temperature and salinity and can fast for months (up to a year) helps to explain their longevity, and so does their decidedly tank-like physique. A hard, smooth shell makes them difficult for predators to handle, and the shell is a bulldozer that allows them to dig into the sand/mud for food. From above, they’re divided into three sections – a curved front shell, a trapezoid-shaped middle segment that is hinged to the front shell, and a long, sharp tail that they use as a rudder and as a pry bar when they get flipped over. They can see potential mates from about three feet away with large compound eyes located on the side curve of the front shell, and several centrally located simple eyes register UV light. It’s murky where they hang out, and the tail is equipped with photo-receptors.
Flip one over and your main impression is legs. The first five pairs are for locomotion and for passing food to the mouth, which is, indeed, surrounded by legs. The final pair is adapted for pushing.
Females are larger than males – some females may measure two feet from stem to stern. When it’s time to breed, horseshoe crabs move into shallow waters. There is some suspicion that females are imprinted on the muck they hatched out of, but it’s not known what – or how – they sense there. A female crawls up on shore, attended by piggyback males https://bugguide.net/node/view/352897/bgimage. She lays eggs, a few thousand at a time (up to 120,000 total), in a depression/”nest” in the sand, the males fertilize them externally, and waves cover them https://bugguide.net/node/view/1396827/bgimage.
Eggs hatch in two weeks and the minute’ young (initially tail-less) head for tidal flats to eat and shed and burrow. Their food supply – clams, worms, a few small fish and crabs and other invertebrates – dwell in the mud and sand with them. Rasps on their legs “pre-process” the food, and their sand-filled gizzard finishes the job. They will molt six times, increasing their size by one-third each time, and reaching a half inch by their first birthday. After they blow out the first candle or two, they move to deeper waters, molting once a year and reaching sexual maturity in about ten years. Older horseshoe crabs collect quite a load of hitchhikers during their lives – limpets, sponges, leeches, mussels, crabs, periwinkles, and other snails attach to the shell.
According to Japanese folklore, warriors killed in battle were reborn as horseshoe crabs, eternally roaming the sea floor, celebrated in art and poetry. Eastern tribes of Native Americans harvested horseshoe crabs for food (the muscles in the second section), fertilizer (and they taught the in-coming Europeans this trick), for bowls made from the front part of the shell, and for the sharp tail, used as a tip for fishing spears. The rubbery eggs, roasted “in the shell” are a delicacy in some Asian cuisines, though the roe of one species contains a neurotoxin called TTX by scientists and “Zombie Powder” by practitioners of Vodou.
Horseshoe crabs are armored but not invincible, and they face some unique modern challenges. They are vulnerable to predation by sea turtles, gulls, fish, and crabs (especially as eggs and newly-hatched young), to habitat degradation caused by shoreline development, to pesticide run-off, oil spills, and to being stranded during spawning. Their intersection with humans has not been a happy one – historically horseshoe crabs have been used for human and poultry food and for fertilizer, and today they’re taken and chopped up as bait for conch and eel fishing. Females with eggs are the most desirable bait, and they have even been harvested off their spawning grounds, and it doesn’t take a Brain Trust to see where that road leads.
Alas for the horseshoe crab, researchers discovered in the 1960’s that components of its blood could be used to screen drugs and intravenous compounds/devices for the presence of certain bacterial contaminants. In order to harvest this blood chemical, which is extremely important in today’s medicine, horseshoe crab are caught, relieved of up to one-third of their blood over a period of several days, and then released. In addition, the shell can be used to make absorbable sutures, treat certain eye problems, and speed blood clotting time
When she did her original research six years ago, the BugLady read that the “bleeding” process carried a 3% to 15% mortality rate (a figure offered by the industry). More recent studies suggest that mortality from the process alone could be as high as 30%. Add to that the trauma of being commercially collected and the fact they are stressed by being out of water during the bleeding process (and losing one-third of their blood), and it’s not surprising that they are disoriented and debilitated when they are released, and that females’ ability to spawn may be compromised (In response to criticism, an industry spokesperson noted that, “One of my suppliers built a water slide to put the crabs back into the water. They love it!”). Medical use is expected to go up, not down, but there has been talk of farming horseshoe crabs.
The food web to which Atlantic horseshoe crabs belong is complex and their contribution is vital. In uncountable numbers, horseshoe crab eggs have fueled migrating shorebirds, especially Red Knots, which time their spring migration from South American wintering grounds to coincide with the horseshoe crab spawning season (excellent video at https://www.youtube.com/watch?v=xLy6G53VOPw, and so is the longer one following it) (nice slide show, but cookieshttp://www.arkive.org/red-knot/calidris-canutus/image-G11960.html). They arrive at Atlantic shore staging areas – irreplaceable way-stations in their 9,000 mile journey – with depleted energy reserves. After two or three weeks of gorging on horseshoe crab eggs, rich in calories, protein and fat (they graze from nests uncovered by wind and waves, leaving plenty of intact nests undiscovered), up to a million shorebirds continue their journey to the Arctic circle having doubled or tripled their body weight. In recent years, as horseshoe crab numbers have fallen, so have shorebird populations. And when an animal doesn’t reproduce until it’s ten, like the horseshoe crab, it takes at least a decade to recover.
Today, population trends for the horseshoe crab are a good-news-bad-news story. They are declining in the Northeast and around much of Florida’s coast, but growing along Southeast beaches. Several Mid-Atlantic States have imposed moratoriums on harvesting horseshoe crabs, and populations there are stabilizing. In the Delaware Bay, the proposed take for the last three years has been 500,000 males and zero females. Biomedical companies harvested around 225,000 annually in the ‘90’s, and that number doubled by 2012 https://www.popularmechanics.com/science/health/a26038/the-blood-of-the-crab/. The problem is that because they return the horseshoe crabs to the water, the biomedical companies are not subject to these restrictions, and they are not required to reveal the numbers of animals they process to anyone except the state DNRs (which share it with the Atlantic States Marine Fisheries Commission).
According to an article called “Medical Labs May be Killing Horseshoe Crabs” that appeared in Scientific American in 2016, “The Atlantic States Marine Fisheries Commission’s most recent survey shows that although the number of horseshoe crabs in the Delaware Bay region has stabilized, the female population is just a third of what the bay is capable of supporting, says Larry Niles, a biologist for several nonprofit conservation groups. And the populations along the coasts of New York State and New England continue to decline. ‘Nobody has ever argued that the crab was going extinct. What we’re talking about is the collapse of an ecosystem, because a key species has been reduced extensively,’ Niles says.”
Long story short, the horseshoe crab is considered to be at a higher level of danger than it was in 1996, and populations could drop by 30% over the next four decades. The BugLady is reminded of the Passenger Pigeon, which also occurred in uncountable numbers, and when over-hunting took its toll and the birds disappeared, it was suggested that they must have flown off somewhere, like South America. Or the moon.
Another change – when this episode was originally posted, it was number 200 in the series. Now, we’re sneaking up on 500!
As veteran BugFans can attest, the BugLady is intrigued by galls. How many kinds are there? To quote from the first BOTW on galls (October, 2009) “Lawlor, in Discovering Nature Close to Home, states that North American plants support more than 2,000 kinds of galls – 800 different kinds form on oaks alone, about 125 kinds on roses, and more than 50 kinds on goldenrods (genus Solidago).”
So many galls, so little time.
Why are galls? Here’s the quick and dirty explanation offered in a Wisconsin Extension vineyard report for Door County. “Gall formation in many instances is initiated by egg laying (oviposition) by the adult form of an insect or by feeding of early larval stages. Feeding by certain gall-making insects results in the release of salivary fluids that may contain plant growth regulating substances (Auxins, IAA) and plant digesting enzymes, pectinases, proteases, and cellulases. The growth regulating substances released by feeding insects work in concert with the grapevines’ response to insect attack. The grapevines’ response to mechanical or chemical irritation is to isolate the toxins or invasion, resulting in a tumorous mass of tissue or gall.” In addition to galls caused by insects and mites (and nematodes), various fungi, bacteria, and viruses may cause galls on plants.
Many gall makers have complicated life cycles that, like the waterlily/reddish-brown plum aphids of recent BOTW fame, may include alternate hosts, and both sexual and asexual generations; in many cases, great chunks of their life histories are unknown. A gall maker tends to be named after the gall it makes.
The GRAPE FILBERT GALL is described in “The Ohio Naturalist” journal (December 1914) as a “Bud gall, being a spherical mass 15-50 mm. diameter, of small, lozenge-shaped galls, each about 5 x 15 mm. Leaf-green, covered with a felty yellow or orange pubescence. Infrequent.”
It has been on our radar for some time – according to the 1916 Bulletin of the University of the State of New York, “Apparently the same gall is found on wild frost grape in Illinois and was described and figured by Messrs. Walsh and Riley in 1868. They state that the gall develops from a common center at a point where a [leaf] bud would ordinarily occur….. Large specimens of this gall bear a general resemblance to a bunch of filbert or hazelnuts as they grow on a bush, which led to the designation vitus-coryloides” (Vitus is the genus name for grapes, and Corylus is the genus name for filbert/hazelnut). Its cause is the Filbert gall maker midge now named Schizomyia coryloides, in the fly family Cecidomyiidae. For many galls, there’s not much information that is more recent than these century-old sources; here’s a drawing of it from 1883 http://www.spiderpic.com/stock-photos/istockphoto/11378771-grape-vine-filbert-gall.
One of the big questions about galls is whether (other than cosmetically) they harm a plant. Sometimes. The larger, woodier, heavier galls that inhabit branch tips and persist for a year or more may weigh a branch down and make it more susceptible to wind and rain damage, but many of the smaller galls that grow on leafy tissue are nothing to worry about. Where would they be, after all, if they habitually killed their host plants? The Wisconsin Extension report concludes, “Galls may look destructive, but galls seldom injure the plant. Grapevines can support a large number of galls and still grow and reproduce normally ……. most galls that infect the soft tissue (leaves, tendrils, shoots) of grapevine are of little economic importance.”
A female-only generation exits the galls (one individual per) in late fall https://bugguide.net/node/view/265686/bgimage) and almost immediately oviposits. The all-female (asexual) generation of this tiny wasp alternates with an even tinier sexual generation that hadn’t even been identified as recently as 2009 when researchers managed to rear some.
When the BugLady started photographing this gall, it was green and was attended by ants. Turns out that rough bullet galls are one of a number of species of galls that produce a sweet substance that, like aphid “honeydew,” attracts insects like bees and wasps. And ants https://bygl.osu.edu/node/907. The ants may be deterring both the insects that graze on oak leaves and the parasitic wasps that seek to lay their eggs in the gall. Honeydew-making galls are induced by just a few genera of Cynipid wasps. In her search, the BugLady came across some papers about hairstreak butterflies that feed on honeydew from galls and from scale insects. For BugFans who want to wander down that very interesting side road, see this article in the American Entomologist https://academic.oup.com/ae/article/61/3/160/2194543 and this report on the first report: https://entomologytoday.org/2016/07/07/rare-butterfly-feeds-on-oak-galls-and-other-non-nectar-sources/.
A different Cynipid wasp, Andricusquercuspetiolicola (Quercus is the genus name of the oaks), makes the OAK PETIOLE GALL on various species of white oak. Unlike the bullet gall, this gall is produced in the softer tissue of the petiole (leaf stem), around the base of the leaf, and so it falls off when the tree loses its leaves. The gall starts growing in early spring, as the leaves start, and the gall makers exit by mid-summer. “BugTracks,” the website of Charley Eiseman, co-author of the excellent field guide Tracks and Signs of Insects and Other Invertebrates, has some amazing pictures in his blog: https://bugtracks.wordpress.com/2013/11/25/two-year-gall/.
Someday, the BugLady will write a book about trying to pry information about this wasp from the ether (once she figured out that it isn’t a Sphex or a Podalonia); it will be subtitled (with apologies to Judith Viorst) “Google has aTerrible,Horrible, No Good, Very Bad Day” (and possibly sub-sub-titled “Net Neutrality and Entomological Research? Really??”). Anyway – different pulpit.
The BugLady found one common name for Palmodes dimidiatus – the Florida Hunting Wasp – though it was not universally embraced. FHWs are in the family Sphecidae, the thread-waisted wasps (loosely called digger wasps), a family that contains some large and handsome, metallically-colored wasps that are named for the elongated constriction (called the petiole) between the thorax and abdomen. We have visited them before in the form of the Great black wasp, the Golden digger wasp, Thread-waisted wasps, Cricket hunters, and Mud daubers. All lead, as do the vast majority of wasps and bees, solitary rather than communal lives. Because they have no hive full of sisters to defend, solitary wasps are – generally – less likely to inflict pain on observers. Despite the fact that they are conspicuous on flowers in high summer, they are an under-studied group.
It’s a small family, with about 125 members in North America. They mostly live out in the open and make nests in the ground for their eggs. Adults feed on nectar (they’ll sip from extrafloral nectaries, of previous BOTW famehttp://uwm.edu/field-station/ants-in-my-plants/), and they sometimes partake of honeydew and of the bodily fluids of some of the invertebrates they capture for their young. They’re considered pollinators.
There are 10 species in the genus Palmodes (either, says bugguide.net, from the Latin for “palm tree” or “hand,” or from the Greek for “vibrating” or “throbbing”). The FHW is found across the continent, but it’s the only member of its genus in the eastern half of North America. Palmodes specialize in the katydids (Tettigoniidae), and some western species prey on Mormon crickets (which are actually katydids and may be 2 ½ inches long). The FHW prefers immature Shield-backed katydids (Atlanticus).
Female FHWs dig a tunnel https://bugguide.net/node/view/1167453/bgimage in loose or sandy soil and make a widened chamber at the end. She digs by biting at clumps of dirt, and scraping the loosened chunks away using the “combs” on her front legs. She forms loose soil into a ball that she tucks “under her chin,” holding it against her mouthparts with her front pair of legs and walking on the other four legs back up to the surface. She saves the soil in a small pile. When she is finished excavating, she plugs the tunnel temporarily and flies off to find a katydid.
She’s about an inch long, but she routinely tackles prey that is much larger than she is (studies suggest that she will go after the biggest prey she can handle), grabbing it, paralyzing it by stinging it once at the base of each set of legs and finally in the throat, then straddling it and dragging it back to the nest https://bugguide.net/node/view/64743/bgimage and https://bugguide.net/node/view/1375820/bgimage. Unlike some other solitary wasps, she makes only one chamber per tunnel, and she provisions it with only one katydid. That task complete, she lays a single egg on the still-living katydid, fills the tunnel with the reserved dirt, and disguises its entrance. When her larva hatches, voila – dinner is served. It will eat, grow, and pupate underground, eventually emerging as an adult.
In his book called Reproductive Behavior and Evolution of Tettigoniidae, Darryl Gwynne parses the difference between predators and parasites, “Digger wasps are often referred to not as predators but as parasitoids, “parasites” whose feeding activities eventually kill but do not dispatch the ‘prey’ right away so that it is kept fresh and unspoiled. The line between predator and parasite is blurred because the actual capture of the host insect by the adult wasp is certainly akin to predation, whereas the larva’s slow consumption of its motionless but still living cellmate has all the hallmarks of a parasitic act.”
Words. The BugLady appreciates the nice turn of a phrase; here are two gems she gleaned while researching this wasp.
From Gwynne’s book, in a discussion of Great Golden digger wasps, he quotes Howard Ensign Evans (1962), who said that that “he knows of few things more exciting than sitting by a flourishing colony…..and watching the females soar in, each with a katydid clutched beneath her: crisp, green songsters, creatures of the sunshine and warm, moonlit evenings, doomed to be devoured by flabby grubs in dark chambers.”
And, the dedication of a doctoral dissertation on wasp phylogeny and behavior, “To Burton and Joseph Payne, who walked high steel so the author wouldn’t have to.”
Epiblemas are micromoths, which is a handy but unscientific grouping that has members across several families (and it’s a genus name that is shared with an Australian orchid called “babe-in-a-cradle”). They are in the large and diverse family Tortricidae (TOR-tri-CYE-dye), the leafroller moths. Mmany are considered pests on agricultural plants, and others are used as biological controls of problem plants. They have their own website: http://www.tortricidae.com/morphology.asp.
Where do they fit in the great scheme of things? They’re in the subfamily Olethreutes, a name that, according to bugguide.net, comes “from Greek olethreuonta meaning “destroyer, annihilator,” a term used to describe the devil in Greek biblical texts.” Seems like overkill for a moth with a ¾” wingspan. And, they’re in the tribe Eucosmini, whose larvae feed on flowers or fruits, or roll/web leaves together, or bore in stems or roots, or make galls. Some are generalist feeders, and others are picky eaters. The adults are nocturnal (two of these three were Porch Light Bugs).
The GOLDENROD GALL MOTH (Epiblema scudderiana) is the most famous of the three. Also called Scudder’s Epiblema, it can be found in open areas east of the Great Plains.
The larval food plant is goldenrod; they burrow into the stem and trigger a thin-walled gall https://bugguide.net/node/view/345088/bgimage, and https://bugguide.net/node/view/1230348/bgimage. The write-up at the Storey Lab website (whose motto is “If we knew what we were doing, we wouldn’t call them experiments“) explains: “females lay eggs on the growing tips of goldenrod in the late spring and after hatching the caterpillar bores into the stem and starts to eat. The plant-insect interaction leads to the formation of an elliptical gall with wood-grain like scars on the outside…. In the autumn, the fifth (and final) instar of the caterpillar gets ready for winter. It moves out of the main gall cavity, hollows out the stem below the gall and fits itself snugly and vertically into this space in a head up position. The caterpillar lines the interior of the stem and gall with silk which helps to act as a barrier to water or ice penetration. … To keep from freezing they accumulate ultrahigh concentrations of glycerol in amounts equal to as much as 18-20% of their total body mass.”
Bugguide.net says that “the larva is winter host for 12 parasites.” In a study in western Pennsylvania in the mid-1970’s, researcher John Plakidas found an 11% rate of parasitism in winter galls of Epiblema, and he suggests that “Because many parasitic insects do not synchronize their life cycles with that of their hosts, they must rely on a variety of alternate hosts to maintain establishment within a community. Pepper (1934) stated that a study of non-economic insects inhabiting weeds might yield valuable information in the biological control of injurious insects. From these results it is evident that E. scudderiana plays an essential role as a winter host reservoir for some parasitic insects in Southwestern Pennsylvania. Expanding this concept, it may be advantageous to cultivate this [Solidago graminifolia] and other suitable species of wild flowering plants in and around orchards and field crops to insure a standing host population of specific parasitic insects.” An interesting comment in the face of today’s “clean farming” practices.
Next up is the BIDENS BORER (Epiblema otiosana), which is found over pretty much the same range as E. scudderiana, but in the damper habitats where its host plants (beggar-ticks and tickseed sunflower) grow. Writing in the Journal of the New York Entomological Society in 1932, George C. Decker tells us that it is “…generally regarded as having little or no economic significance. It is, however, of considerable interest because it is an important insect enemy of a group of noxious weeds known as beggar ticks [hey – the BugLady is fond of Bidens] and, also, because it serves as a reservoir for important parasites of several injurious insects”.
Its larvae are stem-borers, but they don’t cause galls to be formed. Decker writes that “Feeding within the stem, the larva spirals downward so that the spiral burrow practically girdles the stem and the top immediately wilts. Decomposition starts and moves steadily down the stem behind the advancing larva which is moving downward at a rate of from one to one and one-half inches per day. Fifty-eight percent of the Epiblema larvae he found were “inhabited,” mostly by the larvae of parasitic flies and wasps. He also observed that larvae could survive being frozen in stems that tipped over into the water.
Finally, the BugLady thinks that this ghostly little moth is EPIBLEMA BOXCANA, a moth that has no common name and no biography that she could find under any name, old or new. Sources that do mention it describe its genitalia in intimate detail, but say “Food plant unknown.” Leaf-tier, gall-maker, root-borer? Don’t know – but it’s at the center of a great story!
It was described and named in 1907 by an entomologist named W.D. Kearfott, a gentleman renowned/reviled for his nomenclatural eccentricities. For BugFans who doubted that entomology can be a blood sport, here are comments by Edward Meyrick, who calls Kearfott out very publically in The Entomologist’s Monthly Magazine in 1912: “In a paper published in the Transactions of the American Entomological Society, Vol xxxiii, 1907, by Mr. W.D. Kearfott, on new species of Tortricina, are a number of specific names that are openly and obviously based on a barbarous and unmeaning gibberish, and in my opinion must be rejected as null and void. They are given, below, and carry their condemnation on their face. … A line must be drawn somewhere, and for my part I propose to draw it here and now. I refuse to accept these names, and shall quote them as synonyms with the syllable (van.) attached, signifying that they are void. I take the responsibility of re-naming the species accordingly, since someone must do it. I regret any apparent discourtesy to Mr. Kearfott, from whom as a correspondent I have received much, kind help, but if he were my own brother, I could not act otherwise” (alas for Mr. Meyrick, once an organism is properly described and named, the name tends to stand unless subsequent taxonomic work reclassifies it. You can’t just rename something because you don’t like its name).
Almost a century later, a spotlight shone again on Kearfort’s approach to assigning scientific names. In the President’s address to the Lepidopterists Society in 2000 (“Nomenclatural Nonsense – Flying in the Face of a Farcical Code”), John W. Brown elaborates“….the names he proposed for new species are among those that are, shall I say, less than scholarly. Actually, Kearfott’s names stand as a tribute to whimsy, whether intentionally or not. … Kearfott approached his new names in a very orderly fashion, apparently leaning on his very thorough knowledge of the alphabet (you know – a, b, c, d…) with his keen ear for a good rhyme. Here are some of Kearfott’s species names (see Table 3): bobana, cocana, dodana, fofana, gogana, hohana – stop me when you see a pattern … and who can forget the concise, euphonious, and memorable gomonana, tomonana, … zomonana, or baracana, caracana, daracana…..Well, I like Kearfott’s names, they remind me of a song from the 1960’s [‘The Name Game’]…” It’s a lovely speech, and the BugLady recommends it: https://www.biodiversitylibrary.org/page/41154536#page/173/mode/1up (click on the plus sign above the page to magnify).
The BugLady likes her wetlands wet, not solid, so she’s diving into her files of aquatic/semi-aquatic organisms in order to evoke the sights and sounds and feel of a summer day. As usual, this has resulted in a few scenic side trips.
Scenic side trip #1 – what are all those fantastic aquatic organisms doing in the dead of winter, anyway? Invertebrates have three options here in God’s country – migration, diapause (suspended animation – hibernation for the cold-blooded) and termination. Most insects overwinter as eggs (ready to hit the road when the weather warms) or as pupae (ready to assume an adult form when the weather warms). A smaller number spend the winter as nymphs/larvae or as adults. Some aquatic invertebrates spend their whole lives in the water, but for others, water is a nursery that they occupy only as immatures. Both permanent and temporary residents are found under the ice or in frigid streams in winter.
Water is, at once, both a hospitable and an inhospitable place to live. It changes temperature slowly, so its inhabitants don’t experience the dramatic fluctuations felt by those of us who live in the air. Water temperatures under the ice are typically about 37 degrees F, often much warmer than the air above. But, ice overhead excludes new oxygen, and a snow cover keeps out sunlight, as well, so submerged plants don’t photosynthesize and add oxygen to the system. Streams may not ice over, which means they are more oxygenated, but colder.
Ice crystals are harmful/lethal to an organism’s cells, and cold-blooded aquatic invertebrates avoid them via both behavioral and physiological adaptations. They become inactive, some build shelters, and some drift down to the deepest, “warmest,” part of a pond. Aquatic invertebrates are freeze-resistant at the cellular level – able to be “supercooled” to about 22 degrees F without having ice crystals form in their tissues because they have eliminated small particles that would serve as the nucleus of an ice crystal. Some are even freeze-tolerant.
WATERLILY APHIDS (Rhopalosiphum nymphaeae) have an alternative plan for winter, which we’ll get to in a sec. Hint – it has something to do with their other common name, the Reddish-brown plum aphid.
The family Aphididae is a big one – about 5,000 species (1,300+ in North America), many of which are considered pests. WLAs are not from around here (their original range is northern Eurasia); they were first recorded in North America in 1890, but now they occur globally except for some really cold spots. They’re often referred to as “adventive,” a word whose definition ranges from “non-native” to “recently introduced and starting to spread” to “introduced but not really naturalized, not able to sustain their population without help.”
WLAs don’t look like they need any help. They can be seen, sometimes in spectacular numbers, on the flowers and floating leaves of both white and yellow water-lilies. Despite their name, they chow down on quite a variety of aquatic plants including duckweed, arrowhead, water milfoil, water plantain, cattail, bladderwort, Potamogeton, and rice. They are at home above the water and below it, using hairs on their bodies to trap/carry air when they submerge to feed; and they can hike along on the surface film to get to new food plants.
They are preyed on by the usual suspects, like ladybugs, syrphid flies, and some parasitoids, all of which experience population booms when large numbers of WLAs are around. While it is true that dragonflies and damselflies will hover and pick off perched insects, the BugLady isn’t sure if this Orange Bluet is taking advantage of the little bits of protein that surround him. But, she has no doubt that the wasp is collecting aphids to feed to larval wasps. WLAs are sovery fruitful that some authors consider them important “shapers” of aquatic habitats.
Other than the fact that they’re semi-aquatic, the lives of WLAs hew pretty much to the general aphid game plan. They’re found on water plants during the summer, wingless females producing more wingless females by parthenogenesis (virgin birth), a system so effective that their population can double in less than a week (she’ll crank out about 50 offspring in all, popping out two to four per day). Literally “popping out” – the young are produced in eggs, but the eggs hatch internally (it’s called ovovivipary). The nymphs mature in a week or so and become mothers themselves (one researcher used the delicious term “virginoparous,” which refers to a wingless female aphid that was produced by and is, herself, reproducing by, parthenogenesis).
As cold weather approaches, there is a winged generation that includes both males and females. They fly away from the water, boy meets girl, genepools are shared, and females lay eggs in bark crevices on a fruit tree like a peach, plum, almond, or cherry. When they hatch in spring, the nymphs (all female) feed on petioles and fruit stalks, attended by ants (myrmecophily) – and are known as Reddish-brown plum aphids. The tree is dubbed the primary host, because the eggs are laid there, and the aquatic plants that they feed on in summer are considered secondary hosts.
Googling the WLA results in a bunch of hits that demonstrate that beauty is, indeed, in the eye of the beholder. WLAs can transmit a number of plant viruses in either stage of their life cycle, and they are considered pests on some plants but are cheered on as biological controls of problem plants like water hyacinth and duckweed.
Scenic side trip #2 – the BugLady found a number of articles with contradictory views about WLAs and a plant called Azolla, as in “Good news, there are WLA-resistant strains ofAzolla!” and “Good news, you can use WLAs to controlAzolla!” Azolla?? Turns out that Azolla, a.k.a. pond fern, duckweed fern, water fern, and mosquito fern is an actual, floating aquatic fern. There are a dozen or so species – two listed in Wisconsin, both on the “watch list” due to their scarcity (https://www.minnesotawildflowers.info/fern/mexican-mosquito-fern).
Because their associated cyanobacterium fixes nitrogen, needed for plant growth, mosquito ferns can spread like crazy and cover/choke the water surface. The mistaken belief that a solid blanket of Azolla prevented mosquitoes from ovipositing led to that common name, but a thick layer of Azolla probably does make it difficult for mosquito larvae (and some other insects) to get to the surface film. Because of the way it covers the water surface, it acts as floating mulch for rice crops and then as fertilizer when it sinks (and it has been used in this way for 1,500 years). Azolla is grown in some parts of the world as a nutritious livestock feed, and it has been suggested as a food for humans, but there are some questions about long-term safety (neurotoxins).
Interesting Azolla story – apparently, about 50 million years ago, give or take, the greenhouse effect was in full swing and the climate of the North Pole was tropical (think palm trees), and large areas of the Arctic Ocean (which was then more fresh than salt) were covered by Azolla. For a million years, masses of Azolla used a lot of CO2 – half of the available CO2 of the time, by some accounts – and when the plants died and sank, they took all that carbon along with them, which reversed the greenhouse effect and initiated an ice age. It’s called the Azolla Effect! An interesting little plant that the BugLady had never heard of. For more about Azolla, see http://www.folkecenter.net/gb/rd/biogas/technologies/water-for-life/azolla/ and https://www.scientificamerican.com/article/can-the-fern-that-cooled-the-planet-do-it-again/.
The BugLady confesses that she doesn’t specifically set out to photograph WLAs up close – usually she’s hanging off a pier by her toes aiming her camera at something bigger; see http://influentialpoints.com/Gallery/Rhopalosiphum_nymphaeae_water_lily_aphid.htm for some great close-ups. The white markings around the thorax of mature WLAs are waxy flakes that are produced by the aphids (https://bugguide.net/node/view/637136/bgimage). E. O. Essig, in “Aphididae of Southern California” (1912) says that the “ventral surfaces of the thorax, head, antennae, and legs are covered with rather long, white flocculence. This is secreted on the lower surface of the thorax and is evidentially gathered up by the appendages coming in contact with it.”
People often ask the BugLady what her favorite bug is, and although there’s a crowded field for second place, the Tiger Swallowtail is the hands-down winner. Most Impressive Bug? The Black horse fly (Tabanus atratus) (family Tabanidae) is certainly high on that list, and although she knows that it’s (probably) not going to pursue her (they generally stalk non-human mammals), just seeing one always gives her a bit of a start. We have visited the Black horse fly in the past, but briefly, and it’s time to fill in some gaps in its biography. This fly is not the tiny, humpbacked Black fly that lives near rivers and torments all comers.
Yes, there are larger flies in the neighborhood – some of the robber flies, for example, are bigger – but they lack the substance of this fly. The official measurement of 20 to 28 mm (an inch-ish) just doesn’t do it justice. As one bugguide.net correspondent put it: “This is the largest fly I have ever seen, I actually saw two of these at two different locations on the same day. I am guessing it is a horsefly of some sort. A handful of these things ought to be able to carry a horse as a ‘to-go’ meal!”
The Black horse fly is mostly found east of the Rockies. Its larvae live in wet/damp places at the edges of wetlands, and the adults are generally found within a mile or so of the ponds they grew up in.
Their larvae are pale with dark bands https://bugguide.net/node/view/677968 and may be twice as long as their elders when mature. They have pointy mouthparts that can pack quite a punch if you mishandle one.
According to Werner Marchand in the Monographs of the Rockefeller Institute for Medical Research (1920), “Walsh found his aquatic larvae, on many occasions, ‘amongst floating ‘rejectamenta.’ On one occasion, he found six or seven specimens in the interior of a floating log so soft and rotten that it could be cut like cheese.” He goes on to say that “when handled, the larva is, according to Walsh, ‘very vigorous and restless,’ and burrows with great strength between the fingers, and even on a smooth table, walks as fast as any ordinary caterpillar, backwards or forward; when placed in a vessel of water it swims vigorously, twice the length of its body at every stroke...”
According to Marchand, the larvae can produce sound “…the crackling noise was freely produced by full-grown Tabanus atrata larvae, and … was chiefly heard when the larvae were disturbed and defending themselves with their sharp mandibles. The coincidence of the two phenomena was so close that I am bound to assume that the sound was produced by means of the mandibles.”
They climb up onto drier ground to pupate in the soil. Marchand says that “the pupa state lasts but a few days, and before the emergence of the fly the pupa is pushed to the surface of the ground by means of the bristles and thorns of the abdomen, with bending movements of the body.” For more about what happens in a pupal case, see http://uwm.edu/field-station/pupal-cases/.
Much of what is written about Black horse flies concerns their food and feeding habits. The larvae are active predators. Marchand again: “On September 2, 1863, he found a nearly full-grown larva among floating rejectamenta, and between that date and September 23, this larva devoured ‘the mollusks of eleven univalves’ (genus Planorbus) from one-half to three-fourths of an inch in diameter; and on three separate occasions observed it work its way into the mouth of the shell.” They eat other aquatic invertebrates, too, and small vertebrates, and even their tabanid brethren. Jones and Anthony, in The Tabanidae (Diptera) of Florida write “medium to large-size larvae of Tabanus atrata are extremely aggressive. When two or more are placed in the same container, only a short time usually elapses before all are dead except one. The survivor will feed on the victim if hungry, but generally it appears that a larva kills to avoid being killed.”
Like mosquitoes, female tabanids need a blood meal in order to maximize reproduction. Both males and females feed on nectar from flowers (he lacks her piercing mouthparts), but when she is in reproductive mode, a female will stalk livestock and other large mammals by their movement and their CO2 trail. She punctures her victim’s skin with a pretty sophisticated set of blades and is classed as a sanguivore – more specifically, she is a telmophage, because she laps up the resulting pool of blood instead of sucking it (unlike mosquitoes, who are “vessel feeders” or solenophages that employ a “syringe and pump”).
Humans are generally not targets, but a bite is, apparently, unforgettable. When present in numbers, these flies can be a problem for livestock due to blood loss, distress, and potential disease transmission.
Several resources pointed out something that the BugLady had never really thought about before – that being a sanguivore, getting a meal by puncturing an animal that is larger and that takes exception to being punctured, is a dangerous way to make a living. The blood is, as one researcher points out, “not freely given,” and a potential victim may simply swat its tormentor away or may eat it. The BugLady once went on a canoe trip on the Oconto River in Wisconsin where she was accompanied by clouds of deer flies and learned to swat them without breaking stroke, and after nine hours on the water, there was a layer of dead deer flies over the bottom of the canoe (the 50 yards of whitewater just before the pull-out spot were pretty memorable, too).
Another down-side of blood-feeding is that depending on the body temperature of the “pierc-ee,” the piercer is courting temperature shock by ingesting a substance that is much warmer than it is.
The “take-home” is that sanguivores need to do their work in a hurry (solenophages tend to get in and out more quickly and quietly than telmophages), and that the nutrition received needs to be worth the energy – and risk – required to extract it.
Introducing some insects that, while not totally unsung, still have a pretty low profile.
The YELLOW-HEADED CUTWORM (Apamea amputatrix) is a lovely little moth that’s named for its caterpillar, a caterpillar that has, alas, a bad reputation. The name “cutworm” is given to caterpillars in the family Noctuidae, subfamily Noctuinae, many of which are agricultural pests. A Yellow-headed cutworm feeds at the soil surface. Its long list of host plants includes food crops like lettuce, cabbage, wheat, corn, and fruit tree seedlings, and horticultural plantings like grass and roses – a broad menu that allows it to exist across North America (minus the Great Plains and much of the southeastern US), well up into Canada.
And yet. The Yellow-headed cutworm has a healthy-but-not-huge on-line presence, but it’s not the typical collection of Extension bulletins that mark a real agricultural/horticultural scourge. It’s often lumped into accounts of more impactful relatives; apparently, it can do some damage during “epidemic outbreaks,” but the rest of the time, it’s not an important pest.
What a dynamite oak gall! The CLUSTERED MIDRIB GALL occurs on various white oaks and is caused by a tiny (a few millimeters long) wasp called (not surprisingly) the Clustered Midrib Gall Wasp (Andricusdimorphus) https://bugguide.net/node/view/597513/bgimage. Galls are growths of plant tissue that are (largely) instigated by insects and mites. Oaks host about 40% of the 2,000+ different kinds of galls found in North America, and tiny wasps in the gall wasp family Cynipidae are responsible for a lot galls on oak stems and leaves http://uwm.edu/field-station/galls-ii/.
Many gall-makers lay a single egg at a time, but the female CMGW lays her eggs in clusters, and so these lovely ¼” to ½” galls occur in clusters. Albert Kinsey, in his Studies of Cynipidae, says that there’s a six week lapse between egg-laying and the first appearance of visible galls, and another few months before the galls are full grown. The galls can be downright rosy in color when young, changing to tan/gray and becoming thin-walled as they age. The adult wasp emerges the following spring to start the whole thing over again.
Tiny as these wasps are, there are wasps that parasitize them, finding their larvae even through the solid, fleshy wall of the gall. According to the folks at Wildwood Park, in Virginia, “If you want to see an adult, your best bet is to take some galls home, put them in a jar and wait to see what comes out. But, maybe not. Although the gall is a good protection from predators, other tiny wasps parasitize the gall wasps, inserting their ovipositors (egg-laying organs) into the gall and laying an egg in the grub. The parasitic wasp egg then hatches into a grub which eats the gall wasp and emerges in its stead. On top of that, still other wasps parasitize the parasites, laying their eggs in the parasitic grub. So what comes out could be a gall wasp, a wasp that ate the gall wasp, or a wasp that ate the wasp that ate the gall wasp.”
Or, as Johnathan Swift once wrote:
“So, naturalists observe, a flea
has smaller fleas that on him prey;
and these have smaller still to bite ’em;
and so proceed ad infinitum.”
This WATERCRESS LEAF BEETLE, a.k.a Mustard beetle (Phaedonviridis) (probably), looks like a mini-version of the Dogbane leaf beetle. It’s in the large and varied Leaf beetle family Chrysomelidae.
The BugLady couldn’t find a lot of contemporary biographical information about this shiny little beetle, but she did find Bulletin 66, printed by the US Department of Entomology in 1910 that discussed a watercress beetle called Phaedon aeruginosa, which turned out to be the same species. According to F.H. Chittenden (Entomologist in charge of Breeding Experiments), the eggs are laid on and both the larvae and the adults feed on the undersides of leaves. The beetles overwinter as adults.
Chittenden goes on to say that “E.A. Fitch has observed the partiality of the latter for watercress and other crucifers that grow in watery places ……… “thebeetles did not swim rapidly, but steadily, and they were seemingly not discomposed by being somewhat out of their natural element. It seems probable that they fly from plant to plant, and like most beetles undoubtedly are able to float for many hours, and perhaps even swim short distances until they reach a landing place.”
