Insects

By Jim White: Senior Fellow for Land and Biodiversity

The Christina River has been one of my favorite Delaware canoeing and kayaking destinations for many years. Cruising with the tide on a late summer day is about as relaxing as it can get.  However, if you are like me, the best part of the experience is searching for wildlife such as American Beaver, Great Blue Herons or basking Northern Red-bellied Cooters and soaring Ospreys.  In the last several years, thanks to my friend Hal White (no relation) I have become very interested in dragonflies and the Christina River is a great place to see several of our common species. Scanning the spatterdock and cattails and other shoreline vegetation can result in observing colorful species such as Green Darner, Twelve-spotted Skimmer, Spangled Skimmer and Blue Dasher. However, my favorite species that makes the Christina its home is the Russet-tipped Clubtail.

A Russet-tipped Clubtail photographed by Jim White on the Christina River.

A Russet-tipped Clubtail photographed by Jim White on the Christina River.

This large species of dragonfly is only found on tidal freshwater rivers and is not particularity common elsewhere in Delaware. Hal White, in his book Natural History of Delmarva Dragonflies and Damselflies, wrote that this species was not recorded in Delaware until 2003 when a University of Delaware student collected it on the Christina River for his required insect collection. Why the species was not recorded earlier is a bit of a mystery but Hal speculates that large tidal rivers are not a place that most skilled dragonfly enthusiasts think of checking for uncommon species.  Since the 2003 lucky find, Hal has confirmed that the Russet-tipped Clubtail is actually fairly common on the river from August through mid-October.  However, although I had been up and down the Christina River many times over the years, I had never noticed this what I now consider, a rather conspicuous insect. That is, until 2008 when Hal and I mounted a mini-expedition by canoe to photograph this handsome dragonfly for his upcoming book.   It did not take long after putting-in, that we observed several Russet-tipped Clubtails patrolling low over the water.  But photographing flying dragonflies from a shaky canoe is a bit of a challenge to say the least.  Lucky for me though, one of them perched on an overhanging branch just long enough for me to get a few photos – mission accomplished.  So if you have a chance to get out along the Christina River keep your eyes peeled for Russet-tipped Clubtails.

A Russet-tipped Clubtail in flight, photographed by University of Delaware Professor, Dr. Michael Moore.

A Russet-tipped Clubtail in flight, photographed by University of Delaware Professor, Dr. Michael Moore.

Check out the next canoe trips on the Christina from the DuPont Environmental Education Center and see what you can find: Saturday, September 26 and Saturday, October 17

Natural History of Delmarva Dragonflies and Damselflies  by Hal White available at the Ashland Nature Center, DuPont Environmental Education Center, or on Amazon.com.

By Hazel Shinholt, Abbott’s Mill Nature Center Teacher/Naturalist

Warm weather is upon us and we see all kinds of insects scurrying about at Abbott’s Mill Nature Center.  One of the insects you may have walked right by (maybe even walked on) and never noticed is the antlion.   Antlions are in the family Myrmeleontidae and order Neuroptera.  They undergo complete metamorphosis.  The larvae look nothing like the adult.  The adults have wings and can look similar to a damselfly. The most noticeable differences are that the antlion has longer antennae that are clubbed at the end and the vein pattern in their wings is different from the damselfly.  The adult antlion is nocturnal but the larval stage is very active during the day.

Antlion Larva showing its big grasping mouthparts that is uses to subdue small insects that fall into its funnel-shaped trap.

Antlion Larva showing its big grasping mouthparts that is uses to subdue small insects that fall into its funnel-shaped trap.

It is larval stage of the antlion that I find most fascinating!  Antlion larvae are ominous looking creatures. They are gray/brown in color, with an oval shaped body covered in bristles, have short legs and large mandibles.  We have many near our meadow habitat at Abbott’s Mill Nature Center.

The Antlion larva waits for prey to drop into the bottom of the funnel-shaped trap, submerged in the sand.

The Antlion larva waits for prey to drop into the bottom of the funnel-shaped trap, submerged in the sand.

Antlion larvae dig a cone-shaped “pit” in loose sandy or dry soil (look for soil that looks like a rain drop hit it and left a cone-shaped impression in the soil).  The antlion buries itself in the bottom of the pit and waits for its next meal to arrive. Only part of its head is visible at the bottom of the pit.  When an ant or other small insect crawls near the edge of the trap, the loose soil gives way and the prey falls into the “pit of death.”    When the prey reaches the bottom, the antlion then grabs the prey with its strong mandibles and drags it under the soil.  It pierces the prey and feasts on the body fluid of the prey.  The antlion has no use for the carcass of the prey and flicks it out of the pit and the cycle begins again.

By Sheila Vincent, Group Program Coordinator

Occasionally we write book reviews on The Nature of Delaware blog, so since we recently added this book to our staff collection, we thought you might want to know about it.

Beetles of Eastern North America

Beetles of Eastern North America, by Arthur V. Evans, is not a field guide.

In fact, this tome, published by Princeton University Press, is beefy enough, and beautiful enough, to be the ultimate geek coffee-table book. It is comprehensive, 560-page, gorgeous, fascinating, and relentlessly technical. Take this random sample from one of the extremely thorough species accounts for example: “…Maxillary palp ornate in male, simple in female. Abdomen with six (male) or seven (female) ventrites…”. If your response to this description is “Um…..what?”, take heart. The book includes a good glossary, lots of excellent labeled illustrations and diagrams, and a dichotomous key, among many other aids to understanding. There are sections on beetle anatomy, when and where to find beetles, their behaviors and natural history, trapping, collecting, pinning…even a segment on rearing.

And of course, there are the striking, full-color photographs. Most depict living beetles in natural surroundings -on leaves, flowers, soil, wood, etc – in all their diverse, vivid glory. There is no way to do justice to these photos with mere descriptions, except to say that they actually make it possible to use the words “stunning” and “beautiful” and “beetles” in the same sentence. If you plan to use the book for specimen identification, however, you will need to have your own good photograph of the beetle in question, or ideally, have the specimen in hand.

Bottom line: Beetles of Eastern North America is a wonderful beast of a book. I learn something, and have some nerdy fun, every time I open it, whether it’s to ID a difficult specimen, answer a specific question about beetledom, randomly pick a page and start reading, or just gawk at the splendid photographs.  If you know someone who is seriously into insects, this book will keep them busy and amazed for a really long time.

By Joe Sebastiani, Seasonal Program Team Leader

Until a few weeks ago, the only Giant Swallowtail butterflies I had ever seen were in Florida.  Recently, I have had two of these southern butterflies whiz past me, and finally today, I found one at the Flint Woods Preserve that I was able to get photos of while it was feeding.  What is so special about seeing this large butterfly in Delaware?  They normally are found further south from here, and are considered a rare stray to our area.  This year is different.  People are reporting them from all over the mid-Atlantic and even up into New England.  This is the largest species of swallowtail that can be found in our area, and it is a beauty.  It is dark on the back, with yellow lines that form an “X” near the wingtip.  Underneath, they are largely yellow, with a blue median spot-band.  The tails also have a dab of yellow in the middle.

This Giant Swallowtail was found today at the Flint Woods Preserve.  Normally, they are rare this far north, but right now, they seem to be fairly common.  Photo by Joe Sebastiani

This Giant Swallowtail was found today at the Flint Woods Preserve. Normally, they are rare this far north, but right now, they seem to be fairly common. Photo by Joe Sebastiani

Giant Swallowtail caterpillars usually feed on leaves of citrus plants down south, in fact, in some areas, they are considered a citrus “pest” species.  Around here, there isn’t much citrus to go around, but some observers have seen them laying eggs on potted grapefruit and other potted citrus trees.  Otherwise, the caterpillars have been known to feed on Prickly-ash shrubs.  Too bad there isn’t any of that in Delaware either, at least not in the wild.  It historically occurred here, but is thought to be extirpated.  So what are these Giant Swallowtails doing here???  Who knows, but it could have to do with a super-abundance of them in one area, forcing them to leave to find new food resources, or it could have to do with weather patterns or other factors we haven’t considered.  One thing is for sure, they are here, and you have a good chance of seeing them over the next few weeks.

From this angle, you can see the upperside of the wing, which is black, and has a yellow "X" near the tip.  The tails are black with a yellow dot in the center.  Photo by Joe Sebastiani

From this angle, you can see the upperside of the wing, which is black, and has a yellow “X” near the tip. The tails are black with a yellow dot in the center. Photo by Joe Sebastiani

There are other swallowtail butterflies in the area as well.  Most commonly, you will see Eastern Tiger Swallowtails, which are large and very yellow.  The black form of the Tiger Swallowtail doesn’t have much yellow on it at all.  Black Swallowtails are smaller than Tigers and Giant Swallowtails.  They are black and have yellow lines that do not cross.  Other species include Spicebush and Pipevine Swallowtails, but they also have very little yellow.  So if you see a big, black swallowtail, with yellow lines that cross near the wingtip, and a very yellow underside, it should be a Giant Swallowtail.  Take a look around you flower garden, or go for a walk in a wildflower meadow and report back here if you find any.  You can email photos to me at joe@delawarenaturesociety.org if you want a species confirmation.