Botany

By Jim White: Senior Fellow for Land and Biodiversity

It’s not every day that a new species of animal is found in Delaware. In fact, it is very rare indeed. However, in the summer or 2015 Adam Mitchel, a PhD candidate at the University of Delaware did just that. While collecting insects in a meadow at the Ashland Nature Center for his PhD research project on the effects of invasive alien plants on native insects, Adam found several insect specimens that he could not identify.  After examining them under a microscope in his lab he could only identify them as insects belonging to the Insect Order Thysanoptera commonly called Thrips (both the singular and plural of the noun has an (s). The Order Thysanoptera are minute insects with reduced wings, most species being around 1mm long. All but a few use sucking mouth parts to feed on the stems of plants. Several species are considered pest as they can damage crops and other plants. However, the vast majority of the 6,000 or so species are not pests to humans and are valuable members of the food chain.

This species of Thrips, new to science, was discovered at the Ashland Nature Center by entomologist Adam Mitchel. It has no English common name, but scientifically it is called Konothrips polychaeta.  Photo courtesy of Dr. Mitchel, from Goldarazena et al. (2017).

These tiny insects are not often studied unless they are considered pests and information on the many non-pest species is limited. Lucky for Adam, a professor from Belgium, Dr. Arturo Goldarazena…an authority on Thrips, was visiting the University of Delaware. Adam approached Dr. Goldarazena and asked if he would look at some of the Thrips specimens that he collected.  It did not take long for the professor to realize that he had never seen some of the specimens and declared that Adam might have discovered a new species. Adam agreed to give Dr. Goldarazena the specimens to study back in Belgium.  After an exhausting investigation the new species was described and published in Goldarazena et al. (2017). Its official scientific name is Konothrips polychaeta which loosely translates to “hairy tenacious woodworms”.  At this time, there is no common English name for this new species of Thrips. However, I propose to call it Mitchell’s Thrips.

Andropogon virginicus is the host plant for the newly discovered Thrips. Is the new species found wherever this plant exists??? Photo courtesy of Dr. Mitchel, from Goldarazena et al. (2017).

Finding a new species of animal or plant is a dream for biologists – finding them right under our noses in places like Ashland is even more exciting. Adam found the new species inside the flowers of the broom-sedge, Andropogon virginicus but he believes that Konothrips polychaeta probably feeds and breeds on other grasses and sedges that are abundant in the meadows and marshes at the Ashland Nature Center and beyond. These meadow and marsh habitats have been restored and maintained at several of Delaware Nature Society sites as part of the land and biodiversity management program. The program is dedicated to the conservation and preservation of native species and their habitats.

Dr. Adam Mitchel is a native Delawarean and discovered the new species of Thrips while he was a PhD candidate at the University of Delaware. Photo courtesy of Dr. Mitchel.

Dr. Adam Mitchel is a native Delawarean. He attended St. Marks High School and received his undergraduate degrees at the University of Delaware in Wildlife Conservation, Entomology, Plant Protection, Agriculture and Natural Resources (quad majored), and earned his master’s degree in Fish and Wildlife Management at Montana State University. Adam returned home to University of Delaware to obtain a PHD in Entomology and Wildlife Ecology (concentration: Entomology) at the time of the discovery of the Thrips. Adam is now employed as an Assistant Professor of Entomology at Tarleton State University in Texas.

Reference:

Goldarazena A, Mitchell AB and T. Hance (2017) Konothrips polychaeta sp.n. from Delaware, North America, with a key to the three species of this genus. Zootaxa 4341: 445-450.

Ian Stewart

Happy New Year everyone! If you’re looking for an interesting New Year’s Resolution to get you outdoors, why not seek out and learn about a different tree every month? This is exactly the time of year to spot one of Delaware’s most distinctive trees – the Osage orange.

The Osage orange (Maclura pomifera) is a small to medium-sized deciduous tree native to the Midwest that was originally restricted to a relatively small stretch of Arkansas, Oklahoma and Texas. It is not related to oranges but is in the Mulberry family. The name refers to the bright orange color of its wood and the Osage Nation, a midwestern Native American tribe who used the wood for making bows and apparently supplied early settlers with young plants.

The exposed orange roots of a fallen Osage

Although their original range was small, Osage oranges are now found throughout the lower 48 states after lines of them were planted to provide windbreaks in flat open landscapes such as farmland and isolated homesteads. Lines of Osages were also planted throughout the rest of the country to act as natural thorny fencerows for housing livestock and to delineate driveways and land borders, which is why you most often find Delaware Osages arranged in rows on either side of old country roads. Coverdale Farm Preserve’s famous ‘Avenue of the Osages’ contains no fewer than 72 of these striking trees which were probably planted over a hundred years ago.

Coverdale Farm’s famous ‘Avenue of the Osages’, with fallen fruit in foreground

Gnarly, orange-tinged bark of an Osage

The easiest time of year to identify Osage oranges is in the middle of winter as the bare trees now reveal their distinctive gnarled orange-tinged bark made up of many twisted strips. Some trees still bear their large green fruit, commonly known as ‘monkey brains’, although most of these have now fallen to the ground. Be careful – if they fall on a sidewalk or road they become a slippery hazard to pedestrians and motorists alike!

Osage orange fruit with knobbled surface

Interior of an Osage fruit with some seeds

Osages occur as either male or female trees but only the female trees produce the softball-sized fruit which contains several small seeds within its gooey white flesh. Although the fruit is edible almost all animals ignore it as it is tough, unpalatable and exudes latex, so the clusters of monkey brains simply remain where they fall until they decay. Squirrels do eat the seeds however, which may be why you see so few young trees mixed in with the old ones.

Interestingly, almost every Osage I see has a poison ivy vine growing up its trunk, perhaps because the vine finds it easy to grip onto the furrowed bark. Next time you are a passenger in a car being driven along a country lane, try to spot some rows of Osage oranges. If you spot some it might make you resolve to learn about our local trees in 2019!

This Osage was cut down at Coverdale and has about 90 growth rings, suggesting it was at least 90 years old. The poison ivy vine seen in cross-section on the left of the trunk had 19 growth rings so it had been attached for many years.

Ian Stewart

Jewelweed is a colorful native annual wildflower that is common in damp marshy areas where it grows as a thin bush about 4 feet high. It is also known as ‘touch-me-not’ because of its curious habit of expelling its projectile seeds when the flowers are handled or brushed against. Jewelweed is a classic folk remedy because the juice of its leaves and stems is a well-known antidote to stings and rashes from stinging nettle, which it often grows close to.

Jewelweed growing along the boardwalk at Ashland

Many Delawareans are familiar with jewelweed as it is often found in shaded suburban gardens and parks, but few people realize that there are two species and they usually grow right next to each other! The most common is spotted jewelweed (Impatiens capensis), which is also known as orange jewelweed. This has bright orange petals densely covered with red spots and a long ‘nectar spur’ which curls along the bottom of the flower. The second, less-common species is yellow jewelweed (Impatiens pallida), which is also known as pale jewelweed. This has larger, yellow flowers with only a smattering of red spots and a shorter nectar spur which dangles downward. The leaves of yellow jewelweed have more veins and are more deeply toothed than those of the orange jewelweed. In my experience, spotted jewelweed outnumbers yellow by about 5 to 1.

Side by side views of spotted (left) and yellow (right) jewelweed showing the differences in petal pattern, the length and angle of the nectar spur, and leaf venation

Jewelweed is pollinated by both hummingbirds and bees and watching these insects crawl into the depths of the flower to access the nectar pooled up in the spur is a fun way to spend a sunny afternoon! If you’re very lucky you may get to see a hummingbird feeding from the nectar spur.

A bee burrows into a jewelweed flower in search of nectar

The bee’s back is now coated in pollen from the pollen stalk dangling above it. The bee may now pollinate the next jewelweed it enters!

Both jewelweeds have a long blooming season from late spring through the early fall and are an attractive native wildflower to plant in a damp, shaded corner of your yard to attract pollinator insects and hummingbirds.

Learn more about how you can garden for native plants and wildlife by certifying your yard as a wildlife habitat through the Delaware Nature Society

https://www.delawarenaturesociety.org/what-we-do/protecting-habitats-wildlife/garden-for-wildlife/

 

By Ian Stewart

The buzz around this year’s Native Plant Sale is building to fever pitch! Our plant sale comes at the perfect time as we have finally emerged from the frigid gloom of an unusually long cold winter to find colorful wildflowers emerging all across the state. These ‘spring ephemerals’ are so-named because they only flower for a fairly short time since they start losing the sunlight once the trees leaf out.

We are fortunate to have a lot of fairly common attractive native plants in Delaware, and sometimes these get taken for granted. This is a pity, as several have some surprises in store if you look at them closely. Trout Lilies are a perennial often found growing in clumps which get their name because their mottled leaves resemble the sides of a Brook Trout, a freshwater fish. However, they take between 4 and 7 years to mature so the great majority of the lilies you see don’t produce a flower and have just a single leaf (top photo). Only the older, flowering plants have two leaves (second top). The beautiful nodding Lily flowers are harder to find but tend to occur in small colonies which are often visited by insects (bottom photos).

The familiar Mayapple has a similar subtlety. This distinctive umbrella-shaped wildflower of shady forest floors is often found in dense clusters of what look like identical plants, but if you look closely you will see that some have a forked, Y-shaped stem whereas most have just a single stem (below). Only the Y-shaped stems produce a flower then later the apple-like fruit. Mayapples are actually misnamed, as in May they still only have the white flower, which is found in the base of the fork. The hanging ‘apple’ doesn’t appear until later in the summer, and despite the name, is not pleasant to eat and may even be poisonous so we do not recommend that you try it.

Delaware is blessed with a kaleidoscope of beautiful native wildflowers in our area and below are a few of my favorites (from top, Virginia Bluebell, Cardinal Flower, Great Lobelia, Butterfly Weed).

These beautiful wildflowers are available at a reasonable price at the Native Plant Sale so if you want to able to observe these natural wonders in your own back yard just come on by. As well as their visual appeal they are popular with beneficial pollinator insects like bees and butterflies, so now you can have an idyllic native garden and help nature at the same time!

The Plant Sale is held at Coverdale Farm Preserve (543 Way Rd, Greenville, Delaware) Thursday May 3rdand Friday May 4th from 3pm to 7pm (member days) and Saturday May 5th (10am – 4pm) and Sunday May 6th (11am – 3pm) (open to public). Free admission if you just want to come and browse! Credit cards, checks and cash accepted. Click on the link below for more details.

http://www.delawarenaturesociety.org/NativePlantSale#.WuijZi7wa7Q