What’s all this buzz about bees? And what’s a hymanopteran? Well, let’s see.
Hymanoptera—our bees, wasps, hornets and ants—are generally considered to be our most evolved insects. Some form complex social colonies. Others lead solitary lives. Many are essential pollinators of flowering plants, including cultivars that provide food for people around the world. There are those with stingers for disabling prey and defending themselves and their nests. And then there are those without stingers. The predatory species are frequently regarded to be the most significant biological controls of the insects that might otherwise become destructive pests. The vast majority of the Hymanoptera show no aggression toward humans, a demeanor that is seldom reciprocated.
Late summer and early autumn is a critical time for the Hymanoptera. Most species are at their peak of abundance during this time of year, but many of the adult insects face certain death with the coming of freezing weather. Those that will perish are busy, either individually or as members of a colony, creating shelter and gathering food to nourish the larvae that will repopulate the environs with a new generation of adults next year. Without abundant sources of protein and carbohydrates, these efforts can quickly fail. Protein is stored for use by the larval insects upon hatching from their eggs. Because the eggs are typically deposited in a cell directly upon the cache of protein, the larvae can begin feeding and growing immediately. To provide energy for collecting protein and nesting materials, and in some cases excavating nest chambers, Hymanoptera seek out sources of carbohydrates. Species that remain active during cold weather must store up enough of a carbohydrate reserve to make it through the winter. Honey Bees make honey for this purpose. As you are about to see, members of this suborder rely predominately upon pollen or insect prey for protein, and upon nectar and/or honeydew for carbohydrates.
We’ve assembled here a collection of images and some short commentary describing nearly two dozen kinds of Hymanoptera found in the Lower Susquehanna River Watershed, the majority photographed as they busily collected provisions during recent weeks. Let’s see what some of these fascinating hymanopterans are up to…
SOLITARY WASPS
A Great Black Wasp on goldenrod (Solidago species). Like other solitary wasps, a female Great Black Wasp will sting and paralyze a host insect upon which she’ll deposit her eggs. After hatching, the larvae will begin consuming the host’s body as a source of protein. The parasitized insects are often katydids or grasshoppers.A Great Black Wasp feeding on nectar, a source of carbohydrates. Unlike social bees and wasps, solitary wasps are equipped with a stinger solely used for immobilizing prey, not defending a nest. They are therefore quite docile and pose little threat to humans.A Great Black Wasp powdered with pollen. Hymanopterans that gather nectar and/or pollen are tremendously important pollinators of hundreds of species of plants.A female Thread-waisted wasp (Ammophilia species, probably A. nigricans) drags a paralyzed caterpillar to her excavated nest where she’ll deposit an egg on the body. After hatching, the larval wasp will feed on the disabled caterpillar. The protein will enable the larvae to grow, pupate, and later emerge as an adult wasp.The female Eastern Cicada Killer (Sphecius speciosus) excavates an underground nest with branch tunnels connecting a dozen chambers or more. As the common name suggests, the female wasp paralyzes a cicada, then makes a strenuous effort to fly and drag it back to the nest for placement in a cell. Each male wasp egg is deposited upon just one immobilized cicada, but a female egg is provided with a cache of several cicadas to provide adequate protein for growth to a larger size. Nest cells are sealed with soil, then the larvae hatch in just a couple of days. Within about two weeks, they have consumed the cicada protein and are fully grown. Wrapped in a cocoon, they spend the winter in the nest, then pupate in the spring before emerging as a new generation of adults.The Black-and-yellow Mud Dauber (Sceliphron caementarium) builds a mud-ball nest within which it packs paralyzed spiders to function as a source of protein for its larvae.A Black-and-yellow Mud Dauber at nest.The Pipe Organ Mud Dauber builds this elaborate nest in which their eggs and paralyzed spiders are deposited in cells sealed with mud partitions. After consuming the spiders, the larvae pupate, overwinter, then emerge from their cells as adults during the following spring. To escape the protection of the nest, the new generation of adults bore through the mud walls. Adult Pipe Organ Mud Daubers resemble the Great Black Wasp, but have a white or yellow distal segment on their rear legs resembling a pair of light-colored socks.A closeup of the previous image with the lengths of the nest tubes compressed to show four scavenger flies (Miltogramminae), possibly two species, that have invaded this Pipe Organ Mud Dauber nest. Scavenger flies are kleptoparasites that victimize various solitary bees and wasps, depositing larvae directly into the host species’ nest cells to consume the protein cache stored therein.
CUCKOO WASPS
Cuckoo Wasps (Chrysididae), also known as Emerald Wasps, parasitize the nests of other species of wasps. Females lay their eggs inside the host’s nest, then flee the scene. Upon hatching, larval Cuckoo Wasps feed on stockpiles of prey intended for the host species’ offspring. Like the adult mud daubers that have already matured and departed this nest by digging a hole through the wall of the cell within which they were hatched, the metallic green Cuckoo Wasp in the upper left has just emerged in much the same way.
SWEAT BEES
A Sweat Bee (Lasioglossum species) collecting nectar and pollen on White Snakeroot (Ageratina altissima).Sweat Bees (Lasioglossum species) visit human skin to lick up the electrolytes left behind by evaporating perspiration.Sweat Bees in the genus Lasioglossum demonstrate various social behaviors ranging from species that are solitary nesters to those that create colonies with work forces ranging in size from as few as four to as many as hundreds of bees. Some Lasioglossum practice kleptoparasitism, while others are quite accomplished foragers.A female Augochlorine Green Sweat Bee (Augochlorini) collecting nectar on White Snakeroot. Notice the pollen “baskets” on the rear leg.An Augochlorine Green Sweat Bee (Augochlorini). Sweat bees nest in subterranean cavities and in hollowed out sections of trees.A copper-colored Augochlorine Green Sweat Bee (Augochlorini) collecting nectar and dusted with pollen.
LEAFCUTTER AND MASON BEES
A Leafcutter Bee (Megachile species). Like Mason Bees, female Mason Bees deposit each of their eggs on a “pollen loaf” within an individual cell inside a preexisting tunnel-like cavity in wood, stone, or in the ground. Unlike Mason Bees, female Leafcutter Bees cut a circular piece of leaf to create each of the cells in their nest. After hatching, the larval bee feeds on the pollen loaf, pupates, then emerges from the shelter of the nest to start a new generation, usually during the following year.A Leafcutter Bee (Megachile species) visiting Wild Bergamot. Female Leafcutter and Mason Bees lack pollen “baskets” on their rear legs but instead have pollen “brushes” on the underside of the abdomen to gather the protein they need to create a “pollen loaf” for each nest cell.A Leafcutter Bee (Megachile species) collecting nectar from White Snakeroot.A Mason Bee (Osmia species) emerging from a nest in spring. Mason Bees create nesting cells within preexisting cavities in wood, stone, and other other supporting structures. Within the nest cavity, each egg is deposited atop a cache of pollen and nectar, a pollen loaf, then enclosed behind a partition of mud. The female Mason Bee will usually repeat this process until an entire cavity is filled with cells. During the following spring, a new generation of adult Mason Bees digs its way through the cell walls to emerge and repeat the process. These bees readily use paper straws or holes drilled in blocks of wood for nesting.A mason bee nest box with holes drilled into blocks of wood.Mason Bees seal each cell and the outer end of their nest cavity with mud. These outer nest cells can been parasitized by a variety of wasps. Here, the outer cell of a Mason Bee nest has been victimized by a tiny chalcid wasp (looks like another one to the lower left). Several species of female chalcid wasps (native Monodontomerus species or non-native Pteromalus venustus) enlarge weak points in the outer partition of a mason bee nest, then sting and paralyze the larval bee inside before depositing their eggs. Within the cell. the wasp larvae consume the larval Mason Bee and the “pollen loaf” provided for its growth. These same parasitic wasps prey upon Leafcutter Bees as well.
BUMBLE BEES, CARPENTER BEES, HONEY BEES, AND DIGGER BEES
A Common Eastern Bumble Bee (Bombus impatiens) collecting nectar and pollen on goldenrod. Bumble bees are our sole native group of social bees. Their wax nests are built in a burrow or other shelter. The eggs are deposited in cells along with a supply of pollen for nourishing the larvae upon hatching. Honey is stored in “honey pots” within the nest. New queens are produced along with male bees during the late-summer and fall. Only the new generation of fertilized queens survive the winter to lay eggs and produce workers to construct a new nest.A pair of Common Eastern Bumble Bees collecting nectar and becoming dusted with pollen. Their fuzzy coats and semi-warm-blooded metabolism allows them to be active in cooler weather than is tolerated by other bees.Flowering plants including the Great Rhododendron find success attracting pollinators to their reproductive blossoms by offering carbohydrate-rich nectar to insects like this Eastern Bumble Bee. The yellow spots on the flower’s upper petal help to guide visitors toward their sweet treat.An Eastern Carpenter Bee feeding on goldenrod nectar. Compare the almost hairless abdomen to that of the bumble bees. Carpenter bees are semi-social insects. Females lay their eggs in cells within galleries bored into wood. These nests are completed with great precision, avoiding creation of any second entrance by mistakenly breaching the outer surface of the excavated wood. Each egg/larvae is provided with a supply of protein-rich pollen. Males often hover outside their mate’s nest to prevent competing males from entering the area.A worker Honey Bee, a female member of a sisterhood of foragers from a nearby hive, visits goldenrod alongside Common Eastern Bumble Bees. Honey Bees were brought to North America during the 1620s, the earliest years of the trans-Atlantic migration of European colonists, to pollinate cultivated plants and to provide a reliable source of honey and beeswax. Within the Honey Bee’s social structure, the queen of each hive lays the eggs to produce the female worker bees. Once each year, male drones are produced along with a new generation of queens.In nature, Honey Bees build hives in tree cavities. Recently, this colony constructed a hive in a screech owl nest box at susquehannawildlife.net headquarters. To provide protein for the hatching larvae, worker bees collect pollen and deposit it within the hexagonal cells of the vertically aligned beeswax combs. After an egg is deposited upon the pollen cache, each cell is sealed with more beeswax. Young females tend these nest combs before maturing and becoming foraging worker bees.In apiculture, Honey Bees are raised in man-made hives. This Pennsylvania Association of Beekeepers display gives visitors to the Pennsylvania Farm Show in Harrisburg a look at the inner workings of a live bee hive. Nectar collected by worker bees is turned into honey to provide the supply of carbohydrates needed to fuel the colony through the winter. Note the honeycombs on the glass.A possible Small Carpenter Bee (Ceratina species) visiting White Snakeroot. Small Carpenter Bees nest inside hollow stems and twigs. Some species are eusocial, with a queen’s daughters and sisters sharing responsibility for finding food and rearing the young. Females overwinter inside a one of the excavated stems and begin a new nest there in the spring.A Digger Bee (possibly Melissodes species) with “pollen baskets” full of pollen collected from nearby flowers. Digger Bees in the genus Melissodes are often known as the Long-horned Bees. These social insects excavate underground nests and many species practice communal living.
SCOLIID WASPS
The Two-spotted Scoliid Wasp (Scolia dubia), also known as the Blue-winged Scoliid Wasp, is most frequently observed feeding on nectar. Scoliid wasps are solitary nesters, though they may assemble into groups while visiting flowers. They often ignore the presence of humans and are seldom disturbed by their presence. Females seek out the burrowing grubs of beetles including the Green June Bug (Cotinis nitida) and possibly the Japanese Beetle. After stinging a grub to paralyze it, the wasp will deposit her egg on its body, then bury it. Upon hatching, the larval wasp will feed on the grub for nourishment as it grows.Don’t like having your watermelon overrun by Green June Bugs while you’re eating? Then you ought to go out of your way to be nice to the Two-spotted Scoliid Wasp.The Double-banded Scoliid (Scolia bicincta) parasitizes beetle larvae as hosts for its larvae. For carbohydrates it relishes flower nectar.
PAPER WASPS
A Northern Paper Wasp (Polistes fuscatus). Paper wasps prey upon numerous garden pests, particularly caterpillars, to collect protein. Though they are social insects equipped with stingers to subdue their victims and defend their nests, paper wasps are surprisingly docile.A Northern Paper Wasp (Polistes fuscatus) feeding on nectar from a goldenrod flower.A Northern Paper Wasp harvesting wood pulp from the side of a mason bee nest box at susquehannawildlife.net headquarters. The pulp is chewed in the wasp’s saliva to create the paper used to construct the colony’s open-cell nest.Common Paper Wasps (Polistes exclamans), also known as Guinea Paper Wasps, at their open-cell nest. This and the nests of most other paper wasps are suspended on a filament or a pedicle. Many paper wasps can excrete an ant repellent on this section of the nest in an effort to prevent invasion. Like many other social hymenopterans, a defending wasp can secrete a pheromone venom during the stinging process to warn the colony of danger at the nest. In winter, Common Paper Wasps seek shelter in stumps and other locations to hibernate.The European Paper Wasp (Polistes dominula) is a non-native species which builds nests in man-made structures including bird houses. To collect protein, they prey on a wide selection of insects and other invertebrates. As such, European Paper Wasps are widespread and successful here in North America.
YELLOWJACKETS AND HORNETS
An Eastern Yellowjacket feeding on lanternfly honeydew. Eastern Yellowjackets derive much of their success from being generalists, collecting carbohydrates from nearly any sweet source, natural or man made. They are quite fond of ripe fruits, flower nectar, and sugary snacks and drinks, especially soda. Protein for nourishing their larvae is derived from the wide variety invertebrates upon which they prey and from carrion. These foods are chewed into a paste form in preparation for placement into the brood cells.A subterranean colony of Eastern Yellowjackets is started anew each spring by a young queen that has survived winter hibernation in diapause, a state of interrupted development. She constructs the new nest’s first cells using pulp made by chewing rotting wood. The first brood of workers scales up construction while the queen continues producing eggs. At the nest, these social insects will viciously attack anyone or anything perceived to be a threat, so give them their space and leave them alone. Many yellowjacket infestations of homes and other buildings are the work of non-native German Yellowjacket (Vespula germanica) [not shown], an invasive species that constructs paper nests in void spaces including walls and attics.Yellowjackets may be moody and aggressive, but they do fall victim to a number of predators. A Robber Fly (Promachus species) has taken down and is devouring this Eastern Yellowjacket.A Bald-faced Hornet (Dolichovespula maculata) feeding on Spotted Lanternfly honeydew on a Tree-of-heaven (Ailanthus altissima). In the absence of nectar-producing flowers, many bees, yellowjackets, and hornets have turned to the invasive lanternfly and Ailanthus combo to turn the sun’s energy into the carbohydrates they need. For protein, they prey upon spiders, flies, caterpillars, and a variety of other insects.To create paper for nest construction, this Bald-faced Hornet is collecting wood pulp from the surface of a weathered picnic table. Away from the nest, these hornets demonstrate a calm, carefree demeanor and can be closely observed.A Bald-faced Hornet nest in a pine tree. These hives are strictly temporary. Within the nest, a generation of drones (males) and new queens are produced late each year. These wasps leave the colony to mate. With the arrival of freezing weather, all inhabitants within the nest, including the old queen, perish, as do the drones that departed to breed. Only the new queens survive winter hibernation to propagate the next generation of wasps, starting with the workers needed to construct a fresh nest and reestablish the colony.Did you ever get the feeling you’re being watched? Don’t go messing around with Bald-faced Hornet nests. The occupants therein, like other social bees, wasps, and hornets, are equipped with stingers and venom for defending their colony. This is an adaptation that has developed over time to assure the survival of populations of these insects. Think about it this way, a solitary wasp that loses a nest loses only their individual brood of offspring. There is minimal impact on the wider local population of such insects. Conversely, a social wasp or hornet that loses a nest loses an entire colony, possibly negating the benefits of their cooperative behavior and threatening the survival of the species. Insects that cooperate to build societies for survival can be more vulnerable to the catastrophic impacts of certain circumstances like disease, weather, and invasion of their colonies. Therefore, natural selection has provided them with contingencies for these dangers, for example, the instinct to construct protective shelters and the adaptation of stingers and venom for defense against intruders and would-be predators. Oh, and by the way, the Bald-faced Hornet can spray venom, often aiming for the eyes, so keep your distance.European Hornets (Vespa crabro), an introduced species, are predatory on a variety of flying insects for protein. For carbohydrates they are attracted to sweets like this lanternfly honeydew on Tree-of-heaven.European Hornets constructing a paper nest in a tree cavity.
POTTER WASPS
A potter wasp (Eumenes species), probably a Fraternal Potter Wasp (E. fraternus), hovering near a European Paper Wasp on Partridge Pea. The female potter wasp builds a small mud nest resembling a tiny clay pot. One of her eggs is inserted and left hanging on a thin thread. Then a paralyzed caterpillar is deposited as a source of protein to nourish the larva upon hatching. Lastly, the pot is sealed with a lid made of wet mud. Upon maturing, the new generation of adult wasps perform a pottery breaking to emerge and take flight.
ANTS
Field Ants (Formica species, possibly Formica pallidefulva) clear the entrance to their underground nest. Field ants are eusocial insects, they work in concert to build, maintain, and defend the nest, rear young, and find food. There is no social caste system. Field Ants are predators and scavengers when collecting protein. For carbohydrates they often rely on the honeydew produced by aphids. As a method of improving and sustaining the production of honeydew, some ant species will tend colonies of aphids by moving the younger individuals from depleted portions of plants to more healthy tissue. Field Ant nests contain chambers used for a variety of functions including raising young and storing food. Some nests include multiple queens and some colonies consist of more than one nest. Ants in the genus Formica are weaponized; they can spray formic acid to repel intruders and defend their colony.
We hope this brief but fascinating look at some of our more common bees, wasps, hornets, and ants has provided the reader with an appreciation for the complexity with which their food webs and ecology have developed over time. It should be no great mystery why bees and other insects, particularly native species, are becoming scarce or absent in areas of the Lower Susquehanna River Watershed where the landscape is paved, hyper-cultivated, sprayed, mowed, and devoid of native vegetation, particularly nectar-producing plants. Late-summer and autumn can be an especially difficult time for hymanopterans seeking the sources of proteins and carbohydrates needed to complete preparations for next year’s generations of these valuable insects. An absence of these staples during this critical time of year quickly diminishes the diversity of species and begins to tear at the fabric of the food web. This degradation of a regional ecosystem can have unforeseen impacts that become increasingly widespread and in many cases permanent.
How can anyone be surprised by the absence of bees and other pollinators in farmland? Manicured and cultivated ground offers little in the way of year-round shelter and food sources for insects and other wildlife.This savanna-like habitat on a south-facing slope provides the abundance of nectar-producing, pollen-rich wildflowers needed to nourish a diverse population of insects including bees, wasps, hornets, and ants. Goldenrods, asters, and White Snakeroot are some of their late-season favorites.
Editor’s Note: No bees, wasp, hornets, or ants were harmed during this production. Neither was the editor swarmed, attacked, or stung. Remember, don’t panic, just observe.
SOURCES
Eaton, Eric R., and Kenn Kaufman. 2007. Kaufman Field Guide to Insects of North America. Houghton Mifflin Company. New York, NY.
There’s something frightening going on down there. In the sand, beneath the plants on the shoreline, there’s a pile of soil next to a hole it’s been digging. Now, it’s dragging something toward the tunnel it made. What does it have? Is that alive?
We know how the system works, the food chain that is. The small stuff is eaten by the progressively bigger things, and there are fewer of the latter than there are of the former, thus the whole network keeps operating long-term. Some things chew plants, others devour animals whole or in part, and then there are those, like us, that do both. In the natural ecosystem, predators keep the numerous little critters from getting out of control and decimating certain other plant or animal populations and wrecking the whole business. When man brings an invasive and potentially destructive species to a new area, occasionally we’re fortunate enough to have a native species adapt and begin to keep the invader under control by eating it. It maintains the balance. It’s easy enough to understand.
Japanese Beetles (Popillia japonica) seen here on Halberd-leaved Rose Mallow. Without predation, exploding numbers of this invasive non-indigenous insect can defoliate and kill numerous species of plants in a given area.The Song Sparrow (Melospiza melodia) is a generalist feeder, eating seeds and invertebrates including Japanese Beetles. This species is the omnipresent year-round occupant of shoreline vegetation along the lower Susquehanna River.
Late summer days are marked by a change in the sounds coming from the forests surrounding the falls. For birds, breeding season is ending, so the males cease their chorus of songs and insects take over the musical duties. The buzzing calls of male “Annual Cicadas” (Neotibicen species) are the most familiar. The female “Annual Cicada” lays her eggs in the twigs of trees. After hatching, the nymphs drop to the ground and burrow into the soil to live and feed along tree roots for the next two to five years. A dry exoskeleton clinging to a tree trunk is evidence that a nymph has emerged from its subterranean haunts and flown away as an adult to breed and soon thereafter die. Flights of adult “Annual Cicadas” occur every year, but never come anywhere close to reaching the enormous numbers of “Periodical Cicadas” (Magicicada species). The three species of “Periodical Cicadas” synchronize their life cycles throughout their combined regional populations to create broods that emerge as spectacular flights once every 13 or 17 years.
An “Annual Cicada” also known as a “Dog-day Cicada”, clings to the stem of a Halberd-leaved Rose Mallow at Conewago Falls.
For the adult cicada, there is danger, and that danger resembles an enormous bee. It’s an Eastern Cicada Killer (Specius speciosus) wasp, and it will latch onto a cicada and begin stinging while both are in flight. The stings soon paralyze the screeching, panicked cicada. The Cicada Killer then begins the task of airlifting and/or dragging its victim to the lair it has prepared. The cicada is placed in one of more than a dozen cells in the tunnel complex where it will serve as food for the wasp’s larvae. The wasp lays an egg on the cicada, then leaves and pushes the hole closed. The egg hatches in a several days and the larval grub is on its own to feast upon the hapless cicada.
An Eastern Cicada Killer (Sphecius speciosus) along the river shoreline. Despite their intimidating appearance, they do not sting humans and can be quite docile when approached.
Other species in the Solitary Wasp family (Sphecidae) have similar life cycles using specific prey which they incapacitate to serve as sustenance for their larvae.
A Solitary Wasp, one of the Thread-waisted Wasps (Ammophila species), drags a paralyzed moth caterpillar to its breeding dungeon in the sandy soil at Conewago Falls. For the victim, there is no escape from the crypt.
The Solitary Wasps are an important control on the populations of their respective prey. Additionally, the wasp’s bizarre life cycle ensures a greater survival rate for its own offspring by providing sufficient food for each of its progeny before the egg beginning its life is ever put in place. It’s complete family planning.
The cicadas reproduce quickly and, as a species, seem to endure the assault by Cicada Killers, birds, and other predators. The Periodical Cicadas (Magicicada), with adult flights occurring as a massive swarm of an entire population every thirteen or seventeen years, survive as species by providing predators with so ample a supply of food that most of the adults go unmolested to complete reproduction. Stay tuned, 2021 is due to be the next Periodical Cicada year in the vicinity of Conewago Falls.
SOURCES
Eaton, Eric R., and Kenn Kaufman. 2007. Kaufman Field Guide to Insects of North America. Houghton Mifflin Company. New York.
