Two butterflies seen in the butterfly garden

Nature Mysteries


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What is this white fuzzy thing on my tree? What is this super long skinny worm? What is this white-headed bird? Will this giant wasp in my house sting me? What are these bumps on this log? Why do some plants grow backwards? Are ghost plants parasites?

The Nature Program is bringing some natural science to you by answering your questions about Raleigh's Nature Mysteries! 

Do you have a Nature Mystery question? We'd love to hear from you!

Email questions and photos to WilkersonNaturePreserve@raleighnc.gov Look for more answers to Raleigh's Nature Mysteries coming soon!

What is this white fuzzy thing on my tree?

Raleigh is called the “City of Oaks”, and we all know oak trees normally grow acorns – but sometimes our oak trees will grow other things that seem like they should be growing on a different plant completely – like a ball of wooly “cotton”, or even a round, smooth “apple”!

In the spring, you can find often white or pinkish woolly cotton-like growths on white oak trees. They are the result of a tiny insect called the “Wool Sower Gall Wasp”. These are very small, non-stinging wasps that feed on plants.  When the tiny grubs of these wasps feed on an oak leaf, they produce chemicals that trigger the oak to grow these white cotton balls. The tiny wasp grubs live inside the cotton-ball, where they can feed on it while safely hidden from the sight of predators.

Base of tree with green growing leaves and fluffy white circle

The “Wool Sower” galls of spring are not the only galls of oak trees. In the summer and fall, another kind of plant wasp will trigger growths of round, smooth galls that can be the size and color of a small green or reddish apple. These “Oak Apples” are not edible for people, but they are edible to the Oak Apple Wasp’s larva.

Oak Apple galls can be found on many kinds of red oaks, while Wool Sower galls appear on white oaks.  All these galls are very small compared to the size of an oak tree, and they do the trees very little harm. The tiny, non-stinging gall wasps are themselves eaten by various insect-eating forest animals.  For humans, these tiny insects are another creature adding to the variety and richness of Raleigh’s forest ecosystems.

What is this super long skinny worm?

Long skinny white worm

A long, very skinny worm

Some worms we all know – like earthworms.  But there are other animals around us that are “worm-like” yet are completely unrelated to earthworms.

Earthworms are what biologists call “segmented worms” – you can easily see an earthworm’s body is divided into many small, round sections, with visible creases between each section.

There are other “worm-like” animals living around us with bodies without segments.  These include “flatworms” (with flat, soft, smooth bodies), and “roundworms” (usually very tiny with round, smooth bodies).

The strangest of these worm-like animals may be the “Horsehair Worms”.  These worms can be very long, extremely thin, and quite tough and wiry.  They are usually 6 to 8 inches long, but some species can grow to 6 feet long, while still being only 1 or 2 mm wide.  
 

Long skinny worm on top of plastic container with hand holding it

A typical horsehair worm, about 7 inches long.

These worms are perfectly smooth, without any creases or segments like earthworms have.  (These worms are so different from other “worms” that biologists place them in their own Phylum – the Phylum Nematomorpha.)

The common name “Horsehair Worm” or “Hairworm” comes from the idea that they look like a long, thin, piece of horse-hair magically come to life!

Horsehair Worms are harmless to humans, our pets, and our gardens.  They are predators, which live as internal parasites primarily in large insects, such as grasshoppers, cockroaches, and some beetles.  They eat their insect host from the inside and then leave the dead insect behind to lay eggs in shallow water or in moist soil.  

Until very recently, all North American horsehair worms were believed to be aquatic, but a terrestrial (soil-living) species was recently discovered by Dr. Christina Anaya and colleagues, from the states of Louisiana, Texas, and Oklahoma.

Dr. Anaya has confirmed the ID of Horsehair Worm photos from Raleigh’s Wilkerson Nature Preserve, proving that terrestrial Horsehair Worms live in the Carolinas as well.

If *you* find a terrestrial Horsehair Worm, let us know! Citizen scientists may be the key to unraveling the mysteries of this newly discovered creature in our state.

What is this white-headed bird?

Bird with white head on bird feeder

Bird with white head and shoulders at Wilkerson Nature Preserve bird feeder.

This bird may look like it has snow on its head and shoulders, but it isn’t a snowbird. It is an example of a rare but naturally occurring genetic variation often called “pied” or “piebald” coloration.“Piebaldism” has nothing to do with baldness or feather loss.  It is the name for individuals born with scattered patches of feathers (or hair) that are pigment-free (white).

Piebald individuals are not albinos. True albinos have no melanin pigment and have pink eyes and all-white feathers. Individuals which have normal (dark) eyes but all-white feathers are called “leucistic”, which results from a different genetic trait than albinism. Individuals with partial or patchy leucistic feathers are called “piebald”.

Because piebald birds have normal eyes and some skin pigment, they do not experience the same health difficulties as true albinos. But their white feather patches may make camouflage or attracting a mate more difficult, and seeing a piebald in the wild is a rare occurrence.

It can be difficult to identify albino or piebald birds because their feathers do not show the usual color pattern for their species. In this case, our piebald bird is a Pine Siskin (Spinus pinus).  They are a regular winter visitor in Raleigh, and they love the same nyjer thistle seeds that American Goldfinches (a close relative) also enjoy.
 

Piebald Pine Siskin at Thistle Feeder, with American Goldfinch sitting below

Piebald Pine Siskin at Thistle Feeder, with American Goldfinch sitting below.

This particular piebald bird started visiting Wilkerson Nature Preserve’s birdfeeders in January of 2021, and remained in the area until early March.  There are many Pine Siskins at Wilkerson in winter, but the unique piebald pattern makes this individual instantly recognizable, as many visitors have observed.

Our Pine Siskins will fly north to upper Maine or Canada for the summer, but if this bird happens to return to Wilkerson Nature Preserve next winter, this “snowy” Siskin is one bird we will be sure to recognize again!

Will this giant wasp in my house sting me?

Large wasp bug with long thin tail

Wasp with really long tail

That really is a giant wasp! Including the “tail”, it is almost 6 inches long!

And it has a long name – the “Long-Tailed Giant Ichneumon Wasp” (Megarhyssa macrurus).  It is one of the biggest, longest-tailed wasps in all of North America – and you can find it right here in Raleigh.

Best of all, while these long-tailed wasps may look scary, they are harmless to humans. They do not sting.  
 

Close up photo of wasp bug with delicate wings and skinny body

Male Long-Tailed Giant Ichneumon Wasp, with shorter “tail”

Normally you’d expect to see this wasp outside in a forest in the summer months.  The very long, thin “tail” (called an “ovipositor”) is used by females to lay eggs deep underneath the bark of trees, especially dead or dying trees, which is why this wasp is also called the “Stump Stabber”.  Only the females of this species have the extra-long “tail” – the males are smaller than the females overall, but have similar body colors, mostly brown with yellow stripes.

In the winter, these giant wasps may sometimes be found inside homes – especially if you have brought logs of raw firewood indoors.  The young of Giant Ichneumon Wasps live inside dead wood, where they attack and eat the young of other kinds of wasps that eat wood (these wood-eating wasps are often called “horntails” or “sawflies”).

After eating the wood-eating-wasp larvae inside a log, a Long-Tailed Giant Ichneumon Wasp larva will make a pupa and sleep for months, waiting to emerge from the wood in the next spring or summer.

But if you cut that tree for firewood, and bring it indoors, the warmth of your house can trigger the wasp pupae in the wood to emerge early – even in winter.  This only happens with “raw” firewood.  “Kiln-dried” firewood has been treated with heat to kill any insects that might be living inside.

If you happen to see a long-tailed “Stump Stabber” inside your home or outdoors, don't be scared and enjoy the sight of one of our forest’s most remarkable (and harmless) creatures.  
 

What are these bumps on this log?

Dark black bumps on wooden log on forest floor

Log with mysterious bumpy organisms

Some things in nature are just strange looking – like this log.  It may look weird, or even gross, but even these bumpy organisms have an important role in our world.

These black bumps are commonly known as “Woodwart Fungi” – because they look like warts…on wood. They won’t give you warts, and in many cases, they’re actually helpful to trees!
 

Bumpy black fungus

Close-up view of woodwart fungus

Notice that these “warts” are growing all over a fallen log – not a living branch.  Most woodwart fungi are decomposers that only digest dead wood and bark, and in the process, help release nutrients back into the soil where they can be used again by growing plants.  The round “warts” are the part of the fungus that produces spores, which are released through tiny holes in the tops of the “warts”, and help the fungus spread.  A few woodwart fungi are known to attack living trees, but usually only if the tree was injured or weakened by something else first.

Woodwart fungi are small, often dark-colored, and have a hard, almost crunchy feel that is very different from the soft “mushy” feel of most mushrooms.  Woodwarts just aren’t the kind of fungi that humans would want to eat, and they are easy to overlook.

But if you do look closely, mycologists who study fungi have found many hundreds of kinds of woodwarts in forests throughout the world, and more continue to be discovered.  The Woodwart Family – the Hypoxylaceae – is currently thought to contain nearly 2,000 species, usually distinguished by microscopic features.

Small black bumps on wood branch

A different kind of woodwart fungus

Forests benefit from having so many kinds of woodwart fungi because different woodwarts have the ability to digest wood from different kinds of trees – Birch Woodwarts live on Birch tree wood, but Beech Woodwarts live on Beech tree wood.  It takes many fungal species to recycle all the woody material that would otherwise pile up in a forest. Without fungi and other decomposers breaking dead wood down into the soil, the accumulation of dead sticks and logs would put our forests at a higher risk of dangerous forest fires, and new plant growth would suffer from a lack of nutrients since plant roots cannot directly absorb the nutrients stored inside deadwood.

Recently, scientists have found some woodwart fungi living on tree bark produce chemicals that repel other fungi – including fungi that cause deadly tree diseases. Woodwarts may be doing more for forest health than we ever suspected. 

Why do some plants grow backwards?

Green leaf on forest floor with browned dead leaves

Winter-green leaf of a Puttyroot Orchid

Why do some plants grow new leaves in the winter and die in the summer?

Walking in a Raleigh forest in December, many plants look newly bare and leafless, especially our hardwood trees.  But on the forest floor, there are some plants doing the opposite – they’ve grown new leaves just in time for the winter – leaves that will die and disappear when spring comes.  One forest-floor plant with leaves to look for in winter is the Puttyroot Orchid (Aplectrum hyemale).  The scientific name “hyemale” even comes from the Latin word for winter.  Each Puttyroot plant makes one large, white-striped winter leaf that can be over 6 inches long.

Winter-green plants like Puttyroot do not die completely in the spring – their roots remain alive underground – but they do become dormant and leafless, exactly the opposite of our deciduous forest trees.
 

Deep purple leaf and bright green leaf on forest floor with other browned leaves

Crane-fly orchid winter-green leaves

From a plant’s perspective, sunlight is its food source.  When tall forest trees overhead are covered with leaves, very little sunlight reaches the forest floor.  But in winter, when trees are bare, there may be more sunlight at ground-level than in the summer.  Short plants can take advantage of this by growing their leaves in the late fall, just as the canopy trees’ leaves are dropping.  When spring comes and new tree leaves cast their shade again, these “backward” plants lose their leaves. 

Since these fall-to-spring leafing plants like Puttyroot do not keep leaves year-round, they are not evergreens.  But they are the reverse of the majority of our deciduous plants, which keep leaves from spring-to-fall.  You could call them winter-green or reverse-deciduous perennials.  Several of our native orchids are winter-green, including the Puttyroot and the smaller but more common Crane-fly Orchid (Tipularia discolor).  The scientific name “discolor” describes the two-colored green-purple leaves of this plant.

Flowering orchid with yellow blooms with dark red edges on green stalks

Puttyroot Orchid flowering in April-May

The deep purple color in a Crane-fly Orchid’s winter leaves also serves a purpose.
This color comes from a red-purple chemical called Anthocyanin, which is naturally found in a variety of plants – it makes Red Cabbage “red”, for example.  Experiments have found anthocyanin protects plant cells from cold damage (among other benefits), which is especially important to a winter-green plant that must survive harsher temperatures than summer-growing plants.

Even though reverse-deciduous winter-green plants grow their leaves for the winter, most still produce their flowers in the spring or summer, when the plant is otherwise leafless.  Flower-visiting insects like bees are not active in the cold of winter, so waiting until spring to grow a flower gives these plants a better chance of pollination.  

So when admiring tough winter-green leaves in Raleigh’s December woods, remember that December leaves sometimes make May flowers!  

Are ghost plants parasites?

White flowers of Ghost Plants

White flowers of Ghost Plants

If you’re out hiking in a Raleigh forest in the Fall, you may notice a pure white (or sometimes pinkish) flower stalk growing from the forest floor.  All the flowers and leaves on the stem are white…with nothing green visible at all. We know that most plants make their own food, using chlorophyll to capture energy from sunlight.  Chlorophyll is green, and it gives most plants their green color. Ghost Plants (Monotropa uniflora, also called Ghost Pipes) do not have chlorophyll, and cannot make their own food from sunlight.  So where do they get their food? Answer: They steal it.

This makes Ghost Plants a parasite – but not directly on other plants since Ghost Plants only parasitize soil fungi. Many kinds of fungi live underground in forest soil, where they decompose dead plant matter and use it is food. Ghost Plants cannot directly consume dead plants as food, the way fungi can.  So Ghost Plants’ roots tap into the underground threads of soil fungi, stealing away food from the fungi, and they are not known to give anything back to the fungi in return.

We do have other plants in our fall forests that truly are parasites of other plants.  One is called Beechdrops (Epifagus virginiana) because it taps its own roots into the roots of Beech trees.  Like the Ghost Plant, Beechdrops stems never have green leaves, and they don’t need chlorophyll, since they take all their food from their host, a Beech tree.  Fortunately for the trees, Beechdrop plants are small and do the trees very little harm (if the Beech tree died, all the Beechdrops plants under it would die as well).

The flowers of plants like Beechdrops and Ghost Plants offer both pollen and nectar to visiting pollinator insects, like bees – something that their hosts do not offer, so having parasitic plants in our forests benefits animal diversity, as well as adding some very strange flowers for us to enjoy.

When winter comes, look for the dried stems of Ghost Plants (and Beechdrops, too) still standing upright in the forest.  Their original color will be gone – you could call these blackened winter stems the “Ghost of the Ghost”.

Contact

 

Do you have a Nature Mystery question? We'd love to hear from you!

Email questions and photos to WilkersonNaturePreserve@raleighnc.gov

Look for more answers to Raleigh's Nature Mysteries coming soon!

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