A Dazzling Green Beetle: Six-spotted Tiger Beetle

For the past few weeks, I’ve been seeing dazzling green Six-spotted Tiger Beetles (Cicindela sexguttata) along wooded trails, and even on the paths through my shade garden.  I think of these brightly colored beetles as one of the harbingers of spring. They are most commonly seen from spring through early summer in openings in or next to wooded areas.

Six-spotted Tiger Beetle (Cicindela sexguttata)

This eye-catching beetle is named for the spots on its elytra (outer wings), although the number of spots is variable; an individual may have more or less than six spots.

Six-spotted Tiger Beetle (Cicindela sexguttata) with 6 spots

Six-spotted Tiger Beetle (Cicindela sexguttata) with 8 spots

Six-spotted Tiger Beetle (Cicindela sexguttata) with 8 spots

Sometimes called the Six-spotted Green Tiger Beetle, its coloration is most often a vivid metallic emerald green, but in some individuals it may take on a bluish hue.

Six-spotted Tiger Beetle (Cicindela sexguttata) with bluish coloration

Their large eyes, long legs and sickle-shaped mandibles are characteristic of the tiger beetles.

Six-spotted Tiger Beetle (Cicindela sexguttata). The large eyes, long legs and white sickle-shaped mandibles crossed in front of its head are characteristic of tiger beetles.

When I see a Six-spotted Tiger Beetle, it’s often because it spotted me first.  Their color lets them blend in when they are resting on foliage.  I see them when they dash ahead of me along a trail, stopping after a few feet, always keeping some distance between us unless I approach very slowly and carefully.  The beetles’ large eyes give them a broad field of view, the better to see their prey and avoid predators, which include robber flies, dragonflies, other insects, birds and small mammals.

Six-spotted Tiger Beetles are carnivores.  They eat various insects and other arthropods, such as spiders.  The beetles capture their prey with their large, white, ferocious-looking mandibles.

Six-spotted Tiger Beetle (Cicindela sexguttata) with prey

Even as larva, tiger beetles feed themselves by hunting for their own insect meals. Female tiger beetles dig holes in the ground to lay their eggs, one egg per hole, then the hole is covered with soil.  When the larvae hatch, they enlarge their underground tunnel and stay just below the ground level opening, waiting for a hapless insect to walk by.  With lightening-like speed, the larva juts part way out of its home, grabs its victim with its mandibles, drags it back inside its home tunnel, sprays it with digestive enzymes to liquefy it, filters out any solid bits and drinks the rest.

Adult male Six-spotted Tiger Beetles use their mandibles for an additional purpose.  Even after a pair finishes mating, the male may use his mandibles to retain his hold on the female, preventing any other male from attempting to mate with her.

Six-spotted Tiger Beetles (Cicindela sexguttata). Note that the male, who is the beetle on top, is retaining a hold on the female with his mandibles.

It takes about a year for the beetles to complete their metamorphosis.  Adults may live for a few years, often spending the winter in the same underground tunnel it used in its larval and pupal stages.

The Six-spotted Tiger Beetle is found from southeastern Canada to the Dakotas, south from eastern Texas to Florida. Look for these bright green beetles on a wooded trail near you!

Six-spotted Tiger Beetle (Cicindela sexguttata)

Resources

Eaton, Eric R.; Kauffman, Ken.  Kaufman Field Guide to Insects of North America.  2007.

Evans, Arthur V.  Beetles of Eastern North America.  2014.

Evans, Arthur V.  Field Guide to Insects and Spiders of North America.  2008.

Marshall, Stephen A. Insects Their Natural History and Diversity. 2006.

AnimalSake

University of Connecticut Home & Garden Education Center

Minnesota Seasons.com

Indiana Department of Natural Resources

 

Hackberry, Butterflies and Birds

Common Hackberry (Celtis occidentalis) is a tree whose ridged, warty bark makes it easy to recognize in any season.  It may be easiest to spot in winter, since there are fewer leaves to distract from Hackberry’s distinctive outerwear.

Common Hackberry (Celtis occidentalis)

Look for Hackberry on a winter day that’s a little warmer than normal, and you might be rewarded with a glimpse of one of the butterflies that are among Hackberry’s known associates, the Mourning Cloak and the Question Mark.

Mourning Cloak butterfly

Question Mark butterfly. It is named for the white markings on its wing.

Both of these butterflies survive the winter as adults, spending most of the time sheltering in dry accommodations such as under loose bark, in a woodpile, or in a crevice or hole in a tree.  The butterflies are able to produce an anti-freeze-like substance that keeps them from succumbing to the winter cold.  They are mostly inactive during the winter; they rarely eat and don’t reproduce.  But they may venture out on a warmish winter day to look for a snack of minerals from rotting fruit, dung, sap or mud puddles.  When you are a butterfly that wakes up from a winter nap in northern latitudes, you have to have a flexible diet.  Not many flowers are blooming to offer nectar during the cold winter months.

While these butterflies may be found anywhere in the woods, in the warmer months when reproduction is on their mind, they are known to associate with Hackberry trees because they are one of the species whose leaves the caterpillars of both these butterflies can eat.  In addition to Hackberries, Mourning Cloak caterpillars use the leaves of a variety of trees, including willows, elms, birch, cottonwoods and aspen.  Question Mark caterpillars can also eat elm tree and nettle leaves.

Question Mark caterpillar on Hackberry leaves

In the spring and summer months, you may see additional butterflies whose caterpillars specialize on Hackberry leaves.  These species depend solely on Hackberries for their survival.  They include the curious looking and aptly named American Snout, the Tawny Emperor, and Hackberry Emperor.

American Snout butterfly drinking nectar from Short-toothed Mountain Mint (Pycnanthemum muticum)

The American Snout drinks nectar in addition to seeking out minerals.  Its long ‘nose’ is thought to have evolved to look like the stem of a leaf, which together with the cryptic coloration of its wings helps this butterfly to hide in plain sight, disguised as a dead leaf.

Tawny Emperor

Hackberry Emperor

Because Tawny and Hackberry Emperors rarely nectar, you are most likely to encounter them in or near wooded areas where their caterpillar food is present.  Their diet of minerals from mud, sap, and rotting materials such as fruit and dung is similar to that of the Mourning Cloak and Question Mark.  Hackberry Emperors also find human sweat to be a good nutritional source.  It is the species of butterfly I have most often seen landing on people to get a quick snack!

Hackberry Emperor getting minerals from soil and rocks.

Hackberry Emperor getting minerals from the sweat on someone’s shirt!

Hackberry Emperor getting minerals from the hood of a car. Is it the paint or the dirt?

Not every caterpillar will live to become an adult butterfly, since there are many predators to elude first.  The Hackberry Emperor caterpillar in the photo below has fallen victim to a parasitic wasp. Her larva will develop inside the caterpillar, consuming its insides until the wasp is mature enough to emerge.  As you might expect, the caterpillar is unlikely to survive.

Hackberry Emperor caterpillar, with a predatory wasp.

Several moth species including the IO Moth, and White-marked and Banded Tussock Moths also use Hackberries, among other woody species, as food for their caterpillars.

White-marked Tussock Moth

Banded Tussock Moth

The round growths on the leaves in the photo below are galls called Hackberry Nipple Galls.  They are caused by a type of true bug in a group called psyllids, or less appealingly, jumping plant lice.  The insects develop inside the galls and emerge when they mature.

Common Hackberry with ripening fruit and Hackberry Nipple Galls, caused by Pachypsylla celtidismamma.

Many of these insects are a potential bounty of food for birds.  I watched the young Tufted Titmouse below and its nest mates forage for food and play among the branches of a mature Hackberry.

Tufted Titmouse in Hackberry

Hackberry’s somewhat inconspicuous flowers are pollinated by the wind, blooming at the same time that the leaves are beginning to emerge.  Hackberries are monoecious; they have some flowers with just male reproductive parts, others with just female flowers, with both types of flowers on the same trees.  In the photo below, both male and female flowers are present.  The female flowers have two stigma-tipped styles that are spread in a ‘v’ shape projecting from the flower. (They look like forceps, or they also remind me of the arcade games where you have to use a similar looking tool to retrieve a toy from a glass enclosure.)  The male flowers have five or six anther-tipped stamens that barely project beyond the enclosing sepals.  A tree may even have some flowers with both male and female parts.  Pollen is carried by the wind from the anthers and deposited on the stigmas.

Common Hackberry (Celtis occidentalis) flowers. The female flowers have 2 styles spread in a ‘v’ shape. The male flowers each have 5-6 dark-colored anthers.

If the flowers are pollinated, a fruit called a drupe is produced.  A drupe is a fleshy fruit that has a stony enclosure around the seed inside, like a peach.  The fruit ripens in fall, but may persist into winter. Birds as diverse as Mockingbirds,

Mockingbird

Pileated Woodpeckers,

Pileated Woodpecker

and Wood Ducks eat Hackberry fruit.

A pair of Wood Ducks

Raccoons and squirrels are among the small mammals who eat the fruit.

A raccoon peaking out from its home.

Common Hackberry’s natural habitat includes wooded floodplains and hillsides, and can grow to a height of about 115 feet (35 meters).  It is native in Manitoba, Ontario and Quebec provinces in Canada and most of the United States, from New Hampshire to Montana in the north, south through Utah, New Mexico and east to Florida, except Louisiana, although it is less common in the southern part of its range.   It is also often used as a street tree.

There is a related species, Sugarberry (C. laevigata) that is native in the southern half of the United States and in the western states.  Dwarf Hackberry (Celtis pumila) is native in Ontario, Michigan, and from New Jersey west to Kansas, and south from Texas to Florida.  The butterflies that specialize on Hackberries use these species, too!

Common Hackberry (Celtis occidentalis)

Resources

Allen, Thomas J.; Brock, Jim P.; Glassberg, Jeffrey. Caterpillars in the Field and Garden. 2005.

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Eastman, John.  The Book of Forest and Thicket.  1992.

Eaton, Eric R.; Kauffman, Ken.  Kaufman Field Guide to Insects of North America.  2007.

Eiseman, Charley; Charney, Noah.  Tracks & Sign of Insects and Other Invertebrates.  2010.

Martin, Alexander C.;  Zim, Herbert S.; Nelson, Arnold L.  American Wildlife & Plants A Guide to Wildlife Food Habits.  1951.

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Tallamy, Douglas W.  Bringing Nature Home.  2007

Wagner, David L.;  Caterpillars of Eastern North America, 2005.

Illinois Wildflowers
http://www.illinoiswildflowers.info/trees/plants/hackberry.html
http://www.illinoiswildflowers.info/trees/tables/table153.html

USDA NRCS Plant Database
https://plants.usda.gov/core/profile?symbol=CEOC
https://plants.usda.gov/plantguide/pdf/pg_ceoc.pdf

USDA US Forest Service

Oregon State University College of Agricultural Sciences Department of Horticulture Landscape Plants

 

 

 

Praying for Spring? So is Hobblebush Viburnum

Hobblebush Viburnum (Viburnum lantanoides) in winter

Praying for spring?  Based on appearances, it looks like Hobblebush Viburnum (Viburnum lantanoides, synonym V. alnifolia) is doing the same thing.

Many woody plants can be identified in winter by their distinctive leaf and flower buds, including Hobblebush.  Its leaf ‘buds’ are miniature immature leaves that survive the winter without protective scales.  Since Viburnums have leaves opposite each other along their branches and at branch tips, these leaf ‘buds’ are paired together, a perfect mimic of hands held in prayer.

Hobblebush Viburnum (Viburnum lantanoides) ‘naked’ leaf buds, a term that refers to buds without protective scales.

Where flower buds are present, they nestle between the two leaves in a pair.  In this configuration, the flower buds resemble a moose head, with the leaf ‘buds’ playing the role of moose ears.  That could explain why another common name for this shrub is Moosewood!

Hobblebush Viburnum (Viburnum lantanoides) leaf and flower buds. Do you see the resemblance to a female moose head?

Before the canopy trees have finished leafing out in spring, Hobblebush leaves begin to expand and grow, maximizing their ability to photosynthesize.  At the same time, the flowers also begin to bloom.

Hobblebush Viburnum (Viburnum lantanoides) in spring

Like some hydrangeas, Hobblebush inflorescences have two types of flowers, large sterile flowers around the perimeter of the flower cluster that are incapable of producing fruit, and masses of small fertile flowers in the center.  The sterile flowers open first.

Hobblebush Viburnum (Viburnum lantanoides), with leaves unfurling and sterile flowers blooming. The fertile flowers in the center of the inflorescence are still in bud.

The fertile flowers are where the serious work of pollination takes place.  They open a few at a time over several days, giving the plant a long period during which to lure visitors to help pollinate its flowers. At the same time it’s providing food to those pollinators over many days.  It’s a win-win.

Hobblebush Viburnum (Viburnum lantanoides), with fertile flowers beginning to bloom.

Why would a plant have sterile flowers?  Studies show that there is a higher rate of successful pollination in Hobblebush’s fertile flowers when these showy sterile flowers are present.  The sterile flowers help to advertise the plant’s offerings, luring pollinators to the inflorescence.  The many small fertile flowers make efficient use of the remaining space, offering more chances for the plant to reproduce than would be the case if all of the flowers were as large as those in the outer circle.  Aster family members have evolved a similar strategy.  Many have flower heads with a perimeter of showy but sterile ray flowers surrounding a dense cluster of tiny, tubular, fertile disk flowers.

Hobblebush Viburnum (Viburnum lantanoides) in bloom, with flies foraging on the flowers.

A relatively flat flower cluster like those of Hobblebush Viburnum can accommodate lots of different pollinators, including many bee and fly species.  As an insect moves from flower to flower foraging for food, its body brushes against and picks up pollen from the anthers at the tips of the stamens beneath it. This is an especially effective method of transporting pollen with insects that have hairy bodies to which the pollen can easily adhere.  On the day I observed Hobblebush flowers, flies were the most common visitors.  Flies are important pollinators, especially when the weather is cool; many species are able to fly at lower temperatures than bees.

Hobblebush Viburnum (Viburnum lantanoides) in bloom, with Syrphid fly

If you look closely, you can see that the flies are actually eating the pollen. Many bees and flies harvest both nectar and pollen when they visit flowers.  In addition to eating pollen themselves, female bees gather it to feed their larvae.

Hobblebush Viburnum (Viburnum lantanoides) with Syrphid fly eating pollen. The coloration of this fly mimics a wasp or bee, a disguise to deter predators, but its short antennae identify it as a fly to a discerning eye.

Some butterflies and moths use Hobblebush for food in a different way.  The caterpillars of Spring Azure butterflies and Hummingbird Clearwing moths both eat the leaves or buds of this shrub.

Spring Azure butterfly. Its caterpillars eat the flower buds and leaves of several shrub species, including Hobblebush.

While Hummingbird Clearwing Moths drink nectar from the flowers of many different plants, their caterpillars most frequently eat Viburnum leaves. This mature moth is visiting Swamp Milkweed (Asclepias incarnata) for a quick beverage.

In autumn, Hobblebush leaves turn stunning shades of pink, red and maroon.

Hobblebush Viburnum (Viburnum lantanoides) in fall.

Stunning fall foliage of Hobblebush Viburnum (Viburnum lantanoides)

At the same time the leaves are changing color, the fruit that results from pollinated flowers ripens from green to red, then deepens to a dark blue-black.

Hobblebush Viburnum (Viburnum lantanoides) with ripening fruit

The fruit is a drupe, a fleshy fruit with its seed encased inside in a hard coating.  A peach is an example of a drupe.  Hobblebush fruit is edible for humans, although you may want to avoid those seeds.  Many birds and mammals also eat the fruit, and subsequently ‘disperse’ the seeds, complete with fertilizer.  A few of the animals that eat Hobblebush fruit are pictured below.

American Robin

Northern Cardinal

Hermit Thrush

Eastern Chipmunk

Red Squirrel

In addition to reproducing through its flowers and fruit, Hobblebush can reproduce vegetatively.  Where its branches come in contact with the ground, roots can form and a new shoot can sprout.

Hobblebush Viburnum (Viburnum lantanoides)

Hobblebush Viburnum is a deciduous shrub that can be found in moist woods in Ontario, Quebec, Newfoundland and New Brunswick in Canada, and in the northeastern United States from Maine to northeastern Ohio, south to northern New Jersey and Pennsylvania, and in the Appalachian Mountain region as far south as northeastern Georgia.

Hobblebush is fervent in its belief that spring will eventually arrive.  We should be, too!

Hobblebush Viburnum (Viburnum lantanoides) praying for spring

Related Posts

Asters Yield a Treasure Trove

Nutritious Fall Foliage: What makes leaves so colorful?

Resources

Eaton, Eric R.; Kauffman, Ken.  Kaufman Field Guide to Insects of North America.  2007.

Martin, Alexander C.;  Zim, Herbert S.; Nelson, Arnold L.  American Wildlife & Plants A Guide to Wildlife Food Habits.  1951.

Peterson, Lee Allen.  A Field Guide to Edible Wild Plants of Eastern and Central North America. 1977.

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Spira, Timothy A.  Wildflowers & Plant Communities of the Southern Appalachian Mountains & Piedmont.  2011.

Tallamy, Douglas W.  Bringing Nature Home.  2007

Thompson, Elizabeth H.; Sorenson, Eric R.  Wetland, Woodland, Wildland A Guide to the Natural Communities of Vermont.  2005.

Wagner, David L.;  Caterpillars of Eastern North America, 2005.

Adirondacks Forever Wild:  Shrubs of the Adirondacks

Annals of Botany.  Sterile marginal flowers increase visitation and fruit set in the hobblebush (Viburnum lantanoides, Adoxaceae) at multiple spatial scales.

Biology Discussion

USDA NRCS Plants Database

 

 

A Pledge for the New Year

Song Sparrow with caterpillar (lunch!) surrounded by ripening fruit in a Black Cherry (Prunus serotina) tree.

For the new year and beyond, I pledge to do all I can to help achieve a healthy, diverse world, including reducing fossil fuel usage, and using more plants that are native to the area where I live.

I hope you’ll join me!

 

Oaks Have a Lot of Gall!

In late fall and early winter, oak (Quercus species) trees often stand out from their forest companions, refusing to let go of their richly colored russet and brown leaves long after other deciduous trees are completely bare.  Oaks are members of the Beech (Fagaceae) family, and winter leaf retention, or marcescence, is a family trait.  American Beech (Fagus grandifolia) trees tenaciously hold their leaves until early spring when new leaves are preparing to emerge.

Oak trees, retaining their leaves, stand out in a woodland in late fall.

No one knows exactly why some deciduous trees exhibit this characteristic, but there are several theories.  It may be that the dry leaves are a deterrent to winter browsing by deer, moose and other mammals.  Holding on to leaves until spring may be the trees’ way of time-releasing nutrients for recycling into the soil.  Or the leaves may capture and funnel more snow melt to the tree’s root system.

There are about 600 species of oaks (Quercus) worldwide, with 87 in North America, as well as numerous hybrids.  Oaks are usually categorized in two groups, the white oak group and the red oak group.  They can be distinguished by their leaves.  Trees in the white oak group have leaves with rounded lobes,

White Oak (Quercus alba)

while trees in the red oak group have leaves with pointed lobes or with very narrow ‘pins’ at the tips of their lobes.

Red Oak (Quercus rubra)

Oaks are among the most valuable species for supporting both wildlife and people, in many different ways.

The wind-pollinated flowers of oaks produce acorns, an important food for wildlife.

Acorn of Swamp White Oak (Quercus bicolor)

Many birds depend on this bounty of food, including Jays, Tufted Titmice, Red-headed and Red-bellied Woodpeckers, Ruffed Grouse, Lesser Prairie Chickens, Bobwhite and other quails, and Wild Turkeys.

Red-bellied Woodpeckers are among the many birds that eat acorns.

White-breasted Nuthatches are most often seen foraging for food, mostly insects, in the crevices of tree bark, but they also like fruit, and are named for their habit of tucking seeds and nuts like acorns into a crevice and hacking away at them to consume the tasty treat inside.  They may also cache some acorns for later consumption.

White-Breasted Nuthatch

Even Wood Ducks consume acorns.  They primarily live in forested wetlands where oak trees and acorns may be present. Wood Ducks are just one of the many animals that nest in tree cavities such as those found in oaks.

Wood Duck in fall

Acorns are an important food source for many mammals, from mice, chipmunks, raccoons and squirrels, to bear and deer.

Raccoons are among the many mammals that eat acorns, and may find shelter in oak or other tree cavities.

Eastern Gray Squirrels have a special relationship with oaks.  Not only do they consume acorns and shelter in oak cavities, but in return they help to disperse oak seeds (acorns).  Like the White-breasted Nuthatches, Gray Squirrels cache acorns for later consumption.  Squirrels typically have a very good memory for where they stashed each acorn, often recovering as much as 95% of their hoard.  But the other overlooked 5% may germinate and prosper in their new location.  Oaks also tend to have ‘mast years’ when they produce more acorns than can be easily eaten even over the long winter.  In such years, many acorns may live to become trees.

Eastern Gray Squirrel

Acorns are at their most nutritious before they germinate.  Acorns of trees in the white oak group germinate in their first year.  Squirrels can detect this, and are likely to eat acorns from the white oak group as soon as they are available rather than cache them.  Trees in the red oak group produce acorns that take two years to germinate.  Squirrels are likely to cache acorns from trees in the red oak group, since they remain a viable food source for a longer period of time.

When acorns are plentiful, Gray Squirrels, Blue Jays, White-footed Mice and other acorn consumers tend to eat only about half of each acorn, the half at the opposite end from which the tree seedling will emerge (the end without the ‘cap’).  This part of the acorn has a higher lipid content, the food these animals are seeking, and a lower tannin content, a bitter tasting compound that is off-putting to potential consumers.  The discarded uneaten half acorn will often germinate and produce a seedling.

Studies have shown that in the mid-Atlantic United States, oaks are food plants for the caterpillars of more butterfly and moth species than any other genus of trees, supporting more than 500 species.

Juvenal’s Duskywing nectaring from Spring Beauty (Claytonia virginica). Several Duskywing butterfly species use oaks as caterpillar food.

Red-banded Hairstreaks use the fallen leaves of oaks and sumacs as caterpillar food. The spend the winter in the fallen leaves.

Saddleback moth caterpillars eat oak leaves

Several giant silk moths like this Polyphemus Moth and Luna Moths depend on oaks for caterpillar food.

Insects, and especially caterpillars, are an important source of food for birds and other animals.  It takes thousands of caterpillars to feed a young bird family.  As a result, many of those caterpillars will become a meal before they get a chance to become a butterfly or moth.

Carolina Chickadees need thousands of caterpillars to raise a single brood.

Carolina Wrens need food in the form of the many caterpillars and other insects found on oak trees.

There are other insects whose presence in oak tissue stimulates the oak to produce a gall, an abnormal plant growth with more nutrients than are found in normal tissue.  The insect develops inside the gall, feeding on the nutrient rich tissue inside.  Some oak galls are caused by midges, but many are caused by members of a sub-family of wasps called gall (Cynipid) wasps.  The galls take some of the plant’s resources, but they typically don’t cause any harm to the plant.  Often these galls house additional insects, free-loaders (inquilines) that didn’t stimulate the tree to produce the gall but who live and feed in the gall, sharing it with the original tenant.

The galls on these Pin Oak (Quercus palustris) leaves are caused by a midge, Polystepha pilulae.

This gall on Swamp White Oak (Quercus bicolor) is called a Lobed or Pine Cone Oak Gall. It is caused by a wasp.

This summer my attention was drawn to a Swamp White Oak (Quercus bicolor)  branch by ants rapidly climbing around on several ‘bumps’ that could only be galls.  At this point the galls were somewhat nondescript little growths that turned out to be Oak Bullet Galls.

Ants patrolling galls on Swamp White Oak (Quercus bicolor)

But what attracted the ants to the galls?  Ants are omnivorous. Other insects are important food for them, but they also eat plant material and sweet tasty treats, like nectar.  Since they didn’t have access to the insects inside the galls, I speculated that there was something on the exterior of the gall that enticed them.  When I looked at my photos, they did appear to be eating something, but what?

Ants with Oak Bullet Galls galls on Swamp White Oak (Quercus bicolor)

When I checked on the galls about a week later, their appearance had changed dramatically; they now looked like red Hershey’s Kisses.  The ants were still on duty, and this time when I checked my photos, I could see droplets of nectar oozing out from the sides of the galls.  Mystery solved!  The wasp inside the gall had stimulated the tree to not only produce its home and food, but the home came equipped with a security system – nectaries to lure and pay for protection from predators.

Ant drinking nectar from Oak Bullet Gall on Swamp White Oak (Quercus bicolor). The glistening nectar droplets are especially visible just below the tip of the ant’s right front leg.

My next visit was about two weeks after the Hershey’s Kisses phase of the gall development.  Their appearance had changed again; now each gall had a tan, almost perfectly round exterior.  This time the ants were joined on patrol by several wasp species, each capable of discouraging predators of the gall wasp.

Paper Wasp drinking nectar from Oak Bullet Gall on Swamp White Oak (Quercus bicolor).

Cuckoo Wasp drinking nectar from Oak Bullet Gall on Swamp White Oak (Quercus bicolor).

This seems like an expensive security service for the tree to provide if it only benefits the gall wasp.  It is likely that many of these insect guards also protect the tree itself from other herbivores.  For example, Paper Wasps, like ants, are caterpillar predators.

Oaks also have relationships with many fungi, including species that are edible or provide medicine for humans, insects and other animals.

Hen of the Wood is just one of the many fungi that have a relationship with oak trees.

There is a plant called Squawroot or Cancer-root (Conopholis americana) that depends on oaks for its survival.  Squawroot doesn’t produce its own food through photosynthesis. Instead it taps into the roots of oak trees for its food.

Squawroot or Cancer-root (Conopholis americana)

How are oak trees beneficial for people?   If prepared correctly, some acorns are edible.  The wood is used for building, furniture and cabinet making.  The bark of some species is used for tanning.  Oak trees, especially the inner bark, have numerous medicinal uses.  Most importantly, through photosynthesis, oak trees and other plants produce the oxygen we need in order to breathe.  They help mitigate climate change by removing carbon dioxide and other pollutants from our air and water, providing cooling shade, producing moisture through transpiration, and helping to manage stormwater.

Swamp White Oak (Quercus bicolor)

Not only do oaks have a lot of gall, but they provide immeasurable value to life on earth.

Oak trees stand out in a woodland in late fall

Related Posts

Will Work for Food – Extra-floral Nectaries

American Beech

Resources

Beresford-Kroeger, Diana.  Arboretum America: A Philosophy of the Forest.  2003

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Eastman, John.  Birds of Forest, Yard, & Thicket.  1997.

Eastman, John.  Birds of Lake, Pond and Marsh.  1999.

Eastman, John.  The Book of Forest and Thicket.  1992.

Eastman, John.  The Book of Swamp and Bog.  1995.

Eaton, Eric R.; Kauffman, Ken.  Kaufman Field Guide to Insects of North America.  2007.

Eiseman, Charley; Charney, Noah.  Tracks & Sign of Insects and Other Invertebrates.  2010.

Martin, Alexander C.;  Zim, Herbert S.; Nelson, Arnold L.  American Wildlife & Plants A Guide to Wildlife Food Habits.  1951.

Nelson, Gil; Earle, Christopher J.; Spellenberg, Richard.  Trees of Eastern North America.  2014.

Sibley, David Allen.  The Sibley Guide to Bird Life and Behavior.  2001.

Steele, Michael A.; Koprowski, John L.  North American Tree Squirrels.  2001.

Tallamy, Douglas W.  Bringing Nature Home.  2007

Wagner, David L.;  Caterpillars of Eastern North America, 2005.

Buckeye Yard and Garden Online: Bullet Galls and Their Guards by Joe Boggs, October 2018

Capital Naturalist by Alonso Abugattas

Illinois Wildflowers

Minnesotaseasons.com

Missouri Botanical Garden

Naturalis Historia

Penn State College of Agricultural Sciences, Winter Leaves That Hang On