Wednesday, September 14, 2016

Bald-faced Hornets



     Bald-faced Hornets (Dolichovespula maculata) have a mostly undeserved reputation for being vicious, pests and safety hazards. They are actually fairly beneficial insects with a role in the environment. Sometimes called White-faced Hornets, Bull Wasps, or Blackjackets, these wasps are actually not true hornets, but large aerial yellowjackets. 
     They mostly go unnoticed and cause no issues until suddenly someone becomes aware of their large paper nests and get scared. Now these insects, which have been living in that same place throughout the earlier part of the spring and summer causing no trouble, are seen as a danger and something to be feared and destroyed.

The typical paper nest we often do not notice until late in the season or when the leaves have fallen from the trees.

     Most of the time, Bald-faced Hornets are actually beneficial. They hunt other insect prey (including some pests) and bring them to feed themselves and their developing young. They predate on quite a few insects, considering that a nest can hold 400-700 workers by the end of the season. Interestingly, one of their favorite food items are their smaller cousins, Yellowjacket wasps. They also serve as minor pollinators (particularly late in the season when they visit more flowers to obtain nectar and hunt less since they have less young to feed). 

A Bald-faced Hornet worker visits a plum flower.

     A typical nest starts when an overwintering queen wakes up in the spring and finds a likely location to start her nest. Though most of the time they choose a location in a tree from 2'-60' high, they sometimes will use the eaves of a building or other structure that might give some cover from the elements. The queen chews some wood fiber, mixes it with saliva, and then shapes it into the first hexagonal paper cells that will house her eggs. Each egg takes about 6 days to produce young. She feeds and cares for these, who then become the first workers and will raise, provide, and protect the young until the end of the season. A new paper nest is quite small and has the opening at the very bottom.

A small paper hornets' nest at the beginning of the spring.

     The queen then has the sole duty of laying eggs for the rest of her life. The workers (all female) hunt for prey, raise the young, build, repair, and protect the nest. They add new layers and hexagonal cells until the nest attains the size of a basketball, though some are up to 2' long. The opening often ends up near the bottom but slightly off to the side. It is at this stage that many people notice and start to be fearful of the nest. Bald-faced Hornets, though not vicious, will certainly defend their nest. They will each sting repeatedly any perceived threat to their young. Unlike other wasps, they are also capable of squirting venom often aimed at the face of an intruder, and which can even temporarily blind. Here's a short video of a nest and its guards:

                              https://www.youtube.com/watch?v=X3HVOckYGsY

     By late summer or early fall, the queen starts laying male (drone ) and future queen eggs. Unfertilized eggs become male. The new queens tend to be larger and are hairless (unlike the female workers who have very short "hair" (setae)). Egg production starts to taper off, and eventually there are no more workers or reproductive eggs laid. The old queen dies (some say that in some cases, the workers kill the no longer useful queen). All but the new queens after mating will eventually die off, usually by the time they get a couple of hard frosts. The old nests are durable, easily visible in the winter when the leaves are not around, but start to rot away, with no workers to repair or lap them dry after storms. Nests (except maybe a very few in the deep South) are not used again.

An overwintering Bald-faced Hornet queen.

     The new queen finds a sheltered location to overwinter, often under bark or logs. She will remain in this state (called diapause by some) until mid spring of the following year when she finds a new nest location and starts the cycle all over again. Here's a short video of one I discovered under a log that was overwintering:

                              https://www.youtube.com/watch?v=3JdiA-Ozddw

     Sometimes nests do become a safety hazard where they might cause issues with people. This is normally when the nest is too close to habitation or where people can bump into them. When this happens, the nests do need to be destroyed, as they cannot be safely moved. This is best done by a professional. If someone does decide to try and eliminate a nest on one's own, please do so with caution and not use such ridiculous tactics as burning them. This should be done at night (when they're all home, sluggish due to lower temperature, and trapped inside) using one of the commercial hornet sprays. A flashlight may help to find the nest initially, but should be placed away from the person spraying or turned off so as to not give the workers a target if they come out in defense. The spray should be aimed directly into the opening, not only to get the pesticide inside and not hit unintended targets, but to also to help prevent them coming out against the stream of the nozzle. 
     Most of the time, these insects should be left alone however. They are beneficial and will leave people alone as long as they don't perceive them as a threat. This year, perhaps because of environmental conditions, we seem to have more nests around than other years. The nests I seem to be finding are much lower down than I typically find also. Old country lore claims that you can foretell the severity of snow by observing how low hornet nests are. The lower the nests are, so it is told, the more snow we will get. There doesn't seem to be any scientific reason that this would work, as the hornets are dead long before the snows arrive and so it doesn't matter where they choose to build, but if this is somehow true, we're in for a really deep snow from what I've noticed this year...

Thursday, September 1, 2016

Walnut Caterpillar

A Walnut Caterpillar. You may be able to notice where it spit up on my hand.

     The Walnut Caterpillar (Datana integerimma) is a neat caterpillar with a mixed reputation. One of 13 species of what are sometimes called the Handmaid Moths, the Genus Datana, they can be difficult to tell apart. They all are very social, at least while young caterpillars, forming large groups. When disturbed they also all have an interesting defensive posture. They all in unison lift both ends of their bodies and arch themselves upwards. They may also regurgitate onto anything that attempts to grab them. Older caterpillars sometimes just let go and fall to the ground.

A Walnut Caterpillar starting to give the typical defensive posture of the Datana moths.

     The Walnut Caterpillar is much easier to tell apart than the others, lacking much of the markings the other members of the family have that make them all look so similar. They do indeed feed on walnuts, hickories, and pecans (some claim they feed on a few other species, but that's debatable). This can lead to their being considered agricultural pests, though that's more of an issue in the South where they can have multiple broods and defoliate production trees. In our area and further North, they only have one brood and so usually are not as much of a problem and the trees recover well. They are also a favorite food of many animals, so their numbers are usually kept in check. 
     These caterpillars have what maybe a unique behavior as well, that even other members of their Genus lack. They all molt, shed their skins each time they grow, in unison. Even caterpillars born at different times and of different sizes, all somehow synchronize it so they all shed their skins at the same time and in the same place. This usually results in a huge pile of caterpillars and then left over skins, in what may resemble a big hair ball, in the crotch of the tree.

The remains of the synchronized molt of the Walnut Caterpillars in a black walnut tree.

     As quickly as they seem to have appeared, they all seem to disappear. The last instar (molt) crawls to the ground and pupates underground, starting the process again the next summer.

Wednesday, August 31, 2016

Handsome Trig - Red-headed Bush Cricket

A male Handsome Trig

     One of the most attractive local crickets we have around is the aptly named Handsome Trig (Phyllopalpus pulchellus). The name "Trig" refers to the family of crickets, Trigonidiinae, or Winged Bush Crickets, with 6 species worldwide, but only one in North America. The "Handsome" part is obvious. The scientific Genus name refers to the over sized, leaf-shaped mouth palps. "Pulchellus" means "pretty" or "beautiful" which is very appropriate indeed. I like this much better than its other common name: Red-headed Bush Cricket.
     Whatever you call it, this small (7-9mm) cricket really stands out. Some think the color combination may be protective in that it may mimic toxic bombardier beetles or perhaps jumping spiders. They feed on vegetation and do tend to stay in bushes. The males, as in most crickets, sing (stridulate) using their wings. The females have an extra middle extension, the ovipositor, used to lay eggs. 

A female Red-headed Bush Cricket.

     This is the time of year to keep an eye out for these handsome red-headed bush crickets. If you're lucky, you'll be rewarded with seeing these neat little songsters before they jump away.


Tuesday, August 30, 2016

Buttonbush

Tiger Swallowtails enjoying Buttonbush blooms.

     My all-time favorite pollinator shrub is Buttonbush (Cephalanthus occidentalis). I've not only seen tons of bees, butterflies, wasps and even hummingbirds nectar on the fragrant white globular flowers, but you'd be amazed at all the pollinators who visit the flower heads at night. I've seen many moths, beetles, and other nocturnal fliers attracted to the white blooms and their perfume. Few people of course are out in wetlands to witness these night time visitors.

A Bumblebee and Tiger Swallowtail share a Honeyball treat.

     This wetland shrub goes by a great variety of common names, most associated with either its habitat or flowers: Honeyballs, Button-willow, Pin-ball, Little Snowball, Pond Dogwood, Crane-willow, Globe-flower, and River-bush to name a few. It's scientific name is derived from the Greek for "head" (Cephalo) and "anthus" (flower). Occidentalis refers to it being from the West. It is in the Coffee Family (Rubiaceae). There are 6 other members of the genus.
     This multi-stemmed shrub can grow to 20' (though 5'-12' is more typical) right in the water, though it can take drier conditions as well. It has whorled or opposite leaves and stems. It is often one of the last native trees to leaf out in the spring. The leaves tend to turn yellowish in the Fall. Where it gets sufficient sun, it can bloom profusely, and often for more than a month at a time. The seed heads are round and to some look like old time buttons, thus its most common name. They can hang for most of the winter on the branches. The seeds float and can also get stuck to birds, both of these being the primary means of seed dispersal. 

The winter seed heads.

     At least 24 different bird species have been recorded eating the nutlets (about 8 of these being waterfowl). Nineteen different caterpillar species have been found to feed on it as well, despite the leaves having the toxic chemical cephalathin. But again, it's the large numbers of pollinators that visit this plant that is what really stands out, whether day or night. Here's a short video to give you an idea of its popularity:

                         https://www.youtube.com/watch?v=byOU5rKbwm0

     According to noted ethnobotanist Daniel Moerman, numerous Native American Indian tribes were recorded making use of this woody plant. The Chickasaw made a poultice from its roots to treat sore eyes. The Choctaw not only used the roots for their eyes, but also chewed the bark for toothaches and made a bark tea for both dysentery and fevers. The Kiowa used a root solution for hemorrhages while the Koasati used buttonbush to treat rheumatism and sore muscles. The Meskwaki used the bark to induce vomiting. The Seminole made the most use of it, using it for headaches, diarrhea, urinary disorders, constipation, menstruation, fevers, stomach aches, and as a laxative. 
     During the Civil War, Confederate doctor Francis Porcher was tasked with coming up with homegrown alternatives to items no longer available due to Union blockades and war shortages. Calling it crane-willow, he recorded that a decoction from the roots could be used for persistent coughs and as an anti-venereal. He claimed it made a pleasant syrup for lung issues: "It is thought by many intelligent persons to be a radical cure for consumption." 
     Some people have discovered that this makes a great garden plant. In addition to its fragrant, pollinator favorite blooms, it can take some difficult growing conditions. Its tolerance for wet feet (it is considered a wetland obligate plant) makes it a good choice for rain gardens and to deal with erosion control. It can also take some severe pruning, having evolved to having beavers chew on it. The seed heads (achenes) give winter interest. Of course, few plants can hold a candle to it for butterfly and pollinator gardens. It is easy to see why I consider it my favorite pollinator shrub.

A Pipevine Swallowtail on Buttonbush.

Wednesday, August 17, 2016

Spined Micrathena - Spiny Orbweaver Spider


     If you've taken a walk in the woods lately, you've likely run into a spider web. Chances are pretty good it was the orb web of the Spined Micrathena (Micrathena gracilis) or Spiny Orbweaver Spider. It is one of the most common woodland spiders, and it commonly builds webs across trails. Why does it always build its web across a trail where something will run into rather than parallel to the trail? Because those same trails used by people and larger animals are also the most likely to be used by the flies and other small insects that make up the vast amount of prey for these bizarre shaped spiders. Though they are a nuisance, they are harmless to people. 


Spiny Orbweavers are spiny and hard indeed.

     Female Spined Micrathena Spiders have 10 spines or points above their bodies and are cone shaped below. They can come in a variety of colors, but often are darker below and lighter colored (often white, yellow, or orange) above. This is a form of counter-shading, helping to camouflage them in the dappled light of the forest. They hang head down in the center of their webs, and from above match the darker forest floor, but from below match the lighter colored sky. They can get to about half an inch long and only the females build webs.


When looking at the bottom portion, the body is cone shaped.

     The males are rarely seen. They only have two spines and are very slender, being only half the size as adults than the females. They often station themselves near a female's web seeking an opportunity to mate with her. They have to be careful or the larger female will eat them. 
     The Genus Micrathena is derived from the Greek adjective for "small" and the Greek goddess Athena, who was the patron of the spinning/weaving arts. There are about 100 different species in this Genus, but only 3 in Eastern North America (with one additional one in the West). Micrathena gracilis, the Spined Micrathena, is the most common and ranges all the way to Costa Rica. Its specific name means "slender, slight, or graceful." A neat little name for these web builders. 
     The hard spiny body of the Spiny Orbweaver is likely a protection against predators such as birds and lizards. Since the spiders rarely if ever bite, this is important. They will often try to scurry away to a corner of their web if disturbed. They will also sometimes play dead, lying there immobile with their legs tight against their armored bodies. But their most interesting defense is the low pitched buzz (stridulation) they emit when scared. Next time you approach a web, blow on it and see if you can hear it.


When frightened, Spined Micrathena Spiders may pull their legs tight and rely on their armor for protection.

     Micrathena Spiders are in the family Araneidae, the Orbweavers. Their spiral webs are usually less than a foot across, but are placed 3-7 feet up high, perfect height for someone to walk into. When sunlight hits them, they can be really showy, giving them another common name: CD Spiders, since it might appear as though someone had strung one up across the trail.
     Unlike many other orb building spiders, Spined Micrathenas are diurnal, active during the day. They actually eat their webs (all but the supporting frame threads) every night. It takes them about an hour to build their webs again the next morning. About two thirds of their prey are Diptera, or flies. Spiny Orbweavers are a bit slow and clumsy, so their prey gets away a lot. They also differ from many other spiders in that they bite their prey first before wrapping them up, just the opposite of what most other orb web spiders do. 
     These small and common orb web spiders only live about a year (the males not even that long). By late summer and early Fall, the females will lay their eggs in a fuzzy egg sac hidden off to the sides of their webs. The adults all soon die, but the eggs will overwinter and young spiderlings will hatch out to spread through the forest the next spring. 
     So the next time you run into a web in the woods, it may be that you just destroyed the handiwork work of these little spiders. Before you curse them too badly, remember that they're harmless and doing you a favor by catching flies and other small flying insects. If you see one of their webs across your path, enjoy the craftsmanship along with the unusual color and shape of their maker. 



Monday, July 18, 2016

Cicada Killers or Cicada Hawks

A female Cicada Killer attempts to carry off her prey.

     Eastern Cicada Killers (Sphecius speciosus) are large solitary wasps that go several other common names: Cicada Hawks, Sand Hornets, and Giant Digger Wasps for example. They are in the family Crabronidae, which has 4 species in North America and 22 world wide, all specializing in preying on cicadas. Their scientific name translates to "Wasp" and "showy" respectively.
     They certainly do stand out. They're big, up to 2 inches for females around here. Though solitary, males will form territories around good nesting habitat, guarding what are called leks, or breeding grounds. Since they buzz loudly and fly up to investigate anything flying through their territories, they can be quite intimidating. They grapple mid air, sometimes crashing to the ground while engaged with one another. here's a short video of a male guarding a hole, waiting for an available female to stop by:
                    https://www.youtube.com/watch?v=G8BAQnAKyfI

     Recall however that stingers on bees, ants, and wasps are modified ovipositors, used for egg laying. Since males do not lay eggs, they cannot sting. They do have what amounts to hard tip on the end of their bodies though, a pseudo stinger that can poke, but again, this is all bluff.
     Females Cicada Killers can sting, but almost never do. Researchers have had to hold them in place to illicit stings, and supposedly the stings are no worse than a pin prick. They would only sting if caught by hand, stepped on barefoot, or got trapped in clothing. Walking or mowing over them will not aggravate them into stinging.
     Many people confuse Cicada Killers with the large, introduced European Hornet. These large yellowjacket-like wasps are capable of nasty stings. Since they also hunt large insects, seeming to like to eat cicadas as well, they are often called cicada killers when indeed they're not.

A European (German) Hornet attacks a Cicada. They're often confused with Cicada Killers. A smaller Yellowjacket hovers overhead.

     Female Cicada Killers require a cicada for their young to develop. They hunt for them, stinging them until they're paralyzed. Although you'd think they catch more male cicadas who are singing and advertising their presence than females, they seem to get an equal number of each. They go after the various species of "annual cicadas" (those that come out every year, but individuals may spend several years feeding underground) mostly. The Periodical 13 and 17 year cicadas have evolved to emerge earlier and are done breeding by the time Cicada Killers usually emerge. After stinging a cicada, they carry their prey back to their burrows. Since the weight of a cicada, especially the larger females, is 2-3 times the weight of a female Cicada Killer, that is no easy task. Here's a short video from the Capital Naturalist YouTube Channel showing one attempting to do so:
                        https://www.youtube.com/watch?v=5sdzhAuvBtU

     Cicada Killer burrows average about 6 inches deep, but can go deeper than 2 feet. The females excavate them using their jaws to loosen the soil and then pushing the dirt back out the holes using modified spines on their legs. This means that they are very picky about where they build their nests. They like to choose bare, loose, well drained (often sandy) soil, sunny if possible. Sometimes 2-3 females will share an entrance, but each then digs burrows away from the main tunnel to use as their own chambers.
     Each female has a cell she provisions with the paralyzed cicadas. She leaves one cicada if she decides to lay an unfertilized egg which results in a male Cicada Killer. She will leave 2-3 cicadas if she decides to leave a fertilized egg, resulting in a female wasp. Thus the males are smaller, much smaller if they were provisioned with a small male cicada. Eggs are placed under the second pair of legs of the paralyzed cicada. Females sleep in the burrows at night.

A lek, or breeding area, full of Cicada Killer burrows.

     After a couple of days, the eggs hatch. The larvae feed for about 2 weeks, feeding on the cicada, leaving its vital organs for last so it can stay fresh longer. The young pupate and overwinter in a cocoon, emerging in late June or July of the following year.  All adults die after breeding, none making it past the Fall. Adults nectar at flowers and feed on sap flows, being very minor pollinators.
     Though these huge wasps, among the largest in North America, can be intimidating, they are harmless to people. It is unfortunate that they sometimes choose our lawns, garden beds, window boxes, and playing fields to sometimes build their burrows, but these are beneficial insects. They can be discouraged by mulching or heavily planting the areas they favor, but should just be left alone otherwise. 


Wednesday, July 13, 2016

Eastern (Black) Ratsnakes


     The Eastern Ratsnake (Pantherophis alleghaniensis) is our longest and one of our most commonly seen snakes. Formerly called the Black Ratsnake (Elaphe obsoleta), both it's common and scientific names have been changed and formalized. But many people still refer to it as a Black Rat Snake or simply Black Snake. It is the longest snake in the region, the only one that regularly grows to over 6' in length. The world record is one that measured 101 inches from its snout to its vent. The Virginia record is a 67.3 inch one. Its large size along with ability and tendency to climb trees makes this snakes among the most visible in our area.
     Although the large size of Eastern Ratsnakes may make them seem intimidating, they are harmless to people. They will only bite if threatened or handled, and then only about half the time anyways. They prefer to slither away quickly, sometimes musking the perceived threat with a foul smelling liquid if handled. Eastern Ratsnakes will sometime curl up is an S-shape, hissing, vibrating their tail tips, and striking in an attempt to intimidate the potential predator into leaving it alone. The teeth are relatively small for such a large snake, leaving little pin pricks marks and not really causing any great harm. 
     This is a beneficial creature to have around. As the name suggests, they are superb at controlling rodents, being able to get into their burrows and tackling even large rats, killing their prey by constriction. They are however also opportunists, feeding on whatever is available and small enough for them to eat, including birds, eggs, salamanders, shrews, chipmunks, and sometimes larger prey. Because they are such good climbers, they sometimes get themselves in trouble with people who put up bird boxes that haven't been protected sufficiently, eating the occupants. 


Eastern (Black) Ratsnakes are excellent climbers and are often seen basking in trees.

     But overall, they are great allies and find plenty of rodents in urban areas to satisfy their appetites. They can really gorge themselves when food is plentiful. I once was feeding a large 6'+ ratsnake in a nature center I worked at. I was curious as to how many mice it could eat at one sitting. After 23 mice, I had nothing left to feed it, and it was still looking for more. 

     But ratsnakes can also go long times between meals. They can go months without eating if need be, their cold blooded metabolism being very efficient at not burning up energy reserves. This makes them arguably better at rodent control than other predators such as foxes, owls, hawks, and cats, who not only can't get into the rodent burrows, but also cannot go such long times with out eating, having to either move away or die. Not so with ratsnakes. When the rodents do return, they can resume eating with no real harm to the snakes.
     Luckily many people realize the benefits of having ratsnakes around. Sometimes they're referred to as the "Farmer's Friend" and purposely released into barns and out buildings. Their shiny black coloration, with a bit of white on their chin/neck and partial checkerboard pattern on their bellies helps to distinguish them from some of the other black snakes around. 
     But the young are sometimes confused with other snakes because they differ so much in coloration. They have a blotched pattern along their backs that turns all black as they age. Some people confuse them for other snakes such as copperheads or rattlesnakes (especially since these snakes, like many others, will shake their tails in the leaves and thus sometimes sound like a rattle). One of the best identification features for juvenile ratsnakes is a dark line that crosses the eyes to the mouth, almost like a unibrow. 


A juvenile Eastern (Black) Ratsnake, note the line connecting the eyes and blotched pattern.

     That the young sometimes put on a good show by pretending to be big and bad to scare away dangers sometimes backfires when they encounter people. This use to be a good defense against a predator that wasn't sure if it was dangerous. But now of course this can cause people to be frightened and often ends up with them killing the juvenile snakes. 

     Here's a short video from the Capital Naturalist YouTube Channel that shows you one such display: 
                         https://www.youtube.com/watch?v=uDHhbnsdeEQ 

     Eastern Ratsnakes take at least 4 years to reach maturity and breeding age. They lay their eggs (from 5-44 of them depending on the size of the snake) in late June or July around here. They often seek a rotting log or compost pile, the site helping to keep the eggs warm. If the site is a good one, they may use it year after year. The eggs hatch 60-75 days later, with the parents showing no parental care other than finding a good place to hide the eggs and the young are capable of catching their own prey at birth. If nothing eats them, they can live up to 22 years and 11 months, the record so far in captivity. 

     Eastern Ratsnakes overwinter in a dormant state referred to as brumation. Brumation sites (hibernacula) are often used year after year, with some sites containing several snakes. Occasionally they will share the hibernaculum site with other snake species, including venomous ones such as copperheads and rattlesnakes. This has led to the mistaken belief that they can mate with venomous snakes and thus produce the patterned young. This of course is completely false.
     I always am thrilled when I find an Eastern Ratsnake, often still calling it a Black Rat Snake in my excitement. I always try and tell folks about how beneficial they are, try to allay people's fears. I hope that these great and adaptable snakes can live in harmony with us well into the future. This will benefit people, but I also want our younger generations to be thrilled to find a really big snake, like I always am, and be able to talk about them to their kids in the future.