Insects

All posts tagged Insects

By Derek Stoner, Conservation Project Coordinator

A female Regal Fritillary rests briefly on a yarrow plant at Fort Indiantown Gap. Image by Derek Stoner.

While soldiers train nearby to help in the fight for freedom, we wander along the carefully mowed fields amidst vast meadows ablaze with the colors of black-eyed susans, bull thistle, butterflyweed, yarrow, monarda, and other wildflowers.  Our eyes scan back and forth for the winged creatures that visit these flowers in search of nectar.   The flowers are seeking the same thing we are: butterflies.  In this unique location, one special butterfly is the attraction: the Regal Fritillary

A Great-spangled Fritillary glides above a male Regal Fritillary nectaring on Monarda. Image by Derek Stoner.

These gorgeous butterflies have a discerning taste when it comes to choosing habitat: weedy fields in poor soils that have plenty of violets, the host plant for the Regal Fritillary.  And not just any field will do, as these butterflies thrive in areas of disturbance.  A field that burns every few years spurs re-growth of violets and favorite nectar sources(thistles and milkweeds).   Where do you find such habitat?  At a military training ground, of course.

The sign says it all: You may want to watch your step while searching for butterflies. Image by Derek Stoner.

For the third year in a row, the Delaware Nature Society led a trip to Fort Indiantown Gap in Pennsylvania.  For several days each summer, this National Guard training base opens to the public for tours of its very special treasure.  Naturalists from the Fort led an assemblage of more than a hundred curious folks eager to see these winged wonders.  Amidst firing ranges, rusting battle tanks, ripped parachutes hanging in trees, and the multiple hand grenade training areas, we tiptoed along the trails in search of the rare Regals.  We saw plenty of Regals– likely 50 or more individuals out of an estimated population of more than 1,500 at the base.  That’s the largest single population of this insect in the entire world!

The Delaware state butterfly, the Tiger Swallowtail, is just one of the 81 species of butterflies documented at Fort Indiantown Gap. Image by Derek Stoner.

The intensely-managed and altered habitat at the Fort attracts a diversity of insect species, and our group  identified 25 butterfly species during our visit.  In the vibrant meadows we found other fritillary species like Great-spangled and Variegated, along with other beauties like Bronze Copper, Common Wood Nymph, Zebra Swallowtail, and Pearl Crescent.

If you are interested in butterflies join Delaware Nature Society staff member, Sheila Vincent on the program Butterflies for Grownups, Saturday August 7, 1:00 – 4:00 p.m.  Additionally, if you would like to help with a special citizen science project, we invite you to join us for the annual Butterfly Count sponsored by the North American Butterfly Association.  This year’s count will be held on Saturday, July 31,  beginning at 9:00 a.m.  Armed with nets, cameras, and notebooks, we will document all the butterflies we can find (and identify) at Ashland Nature Center and Burrows Run Preserve.  To register for this free event, contact Sheila Vincent at 302-239-2334, ext. 125. 

By Jim White: Associate Director, Land and Biodiversity

I have been putting off writing this blog entry for about a month. In fact I still am not sure that the following story is “blog worthy” but what the heck – here goes…

It was a beautiful sunny day and I was taking a blissful ride on my motorbike. As I cruised down Brackenville Road I was surprised when I was struck by an insect on the side of my face. Actually, insect strikes are a fairly common occurrence and this one didn’t feel that bad because I was only going 25 mph. However, instead of bouncing off my face as I expected, this bug crawled under my helmet and then into my right ear. I couldn’t stop immediately, but I was close to the Ashland Nature Center and decided to pull in and assess my situation. As I pulled up the driveway I saw Joe Sebastiani walking toward me. Much to his dismay I asked Joe to look into my ear to see if he could see the intruder. Joe made a feeble attempt and informed me he saw nothing.
So I went to my desk figuring that the little creature would soon decide to crawl out and go about its business. But after twenty minutes of trying to identify the bug just by feeling its little legs scratching annoyingly deep inside my ear, I decided to go home and lay down and let gravity assist in the exit. Once I was lying down I had plenty of time to ponder my situation. I started to recall an episode from one of my favorite TV shows of my youth: Rod Sterling’s “Night Gallery”. Some of you might remember the episode erroneously called “The Caterpillar”. The unlucky protagonist has a small insect-like creature (which they call an “earwig”), crawl into his ear. The creature then burrows through his ear and into his brain, causing a slow slide into insanity. Well, just when I was amusing myself with the coincidence, my intruder started to move with more vigor and instead of crawling out it decided to go deeper, finally crawling on my ear drum. This is when I started to think that maybe there was some truth to the TV story.
Luckily, after several very painful minutes, my ento-friend finally decided to make for the daylight and crawl out of my ear. Not only was I relieved physically, I was also finally able to identify the creature. It was not an “earwig” but instead an almost inch-long Rove Beetle (family Staphylinidae). Well, for me that explained why the creature had crawled into my ear canal instead of just flying away. Rove Beetles have a natural ability and affinity to crawl into tight places: they typically are found in and under dead animals where they feed on fly maggots, and they enter carcasses through openings in the skin. As I believe there were no maggots in my ear for it to feed on, I would guess that my visitor was “glad’ to be free. I know I was sure glad to see him go.

Happily, I have suffered no lasting ill effects from the experience, but if you recall the end of the TV story — only time will tell. You see, in the TV story, although the invading insect was removed, it was discovered that it was a female and had laid eggs in the poor fellow’s brain. Do-do-do-doo, Do-do-do-doo! 

Jim on bike photo6
Simulation by Gregory White
Rove Beetle

Rove Beetle

By Jim White, Associate Director, Land and Biodiversity

I have always enjoyed answering questions about wildlife and take a bit of pride in being able to come up with answers quickly. However, every now and then there are questions that are real stumpers. These questions are always the most fun to work on and often require communication with other naturalists, flipping through old field guides, and of course searching the web.

One such question turned up the other day. A friend of mine called me when he and a few of his neighbors discovered an interesting scene on the neighborhood sidewalk. My friend described it as several groups of worm-like things forming a rope and walking en masse in a clockwise circle. The ropes were several “worms” thick and joined head to tail. He was speculating (in jest) that they were an alien life form. To be honest I was wondering if he might be right. Luckily, one of the neighbors, Paul Dreyfus had a digital camera and was able to take a few photos and send them to me. I waited in anticipation, figuring that once I saw the photos I would know exactly what the “worms” were. But noooooo! Although I could tell that they were insect larva I had no idea what kind.

Strange insect larvae walking in a circle on a sidewalk.  Photo by Paul Dreyfus.

Strange insect larvae walking in a circle on a sidewalk. Photo by Paul Dreyfus.

I decided to ask Richard Smith a well-versed entomologist that I know. He was also stumped but did some web searching of his own and found our answer in a photo on an obscure garden listserve. Sure enough the photo was a match – the “aliens” were the larvae of a species of Dark-winged Fungus Gnats (family Sciaridae). As their common name implies, the larvae of these small flies (order Diptera) feed on fungus, but they also eat the root hairs of many plants. Some species are known pests of mushroom cultivation and greenhouse operations.

Dark-winged Fungus Gnats close-up.  Photo by Paul Dreyfus.

Dark-winged Fungus Gnats close-up. Photo by Paul Dreyfus.

So with the identification in hand I set out to find out all I could about these intriguing insects. I figured a few minutes on the web would give me as much information as I wanted on the little guys. Wrong again. So far I have only found out the following:
• The larvae often live in large congregations and from time to time move en masse to new locations.
• In Europe there are several species of Dark-winged Fungus Gnats, especially the army worm Sciara militaris, that migrate in processions up to ten meters long, containing thousands of individuals.
• The circles apparently form when the leading larvae mistakenly hooks up with the larvae at the tail of the “rope”, forming an endless loop.
Many questions remain about why and where the larval migrations occur and how frequently the circles form. I will keep searching for these answers and report my findings (if any) in another blog. Meanwhile, please contact me if you’ve seen, or have additional information about, these “alien worm circles”.

Jim White, Associate Director, Land and Biodiversity
Top wing view

Milbert's Tortoiseshell Burrows Run Preserve 28 September 2009 11

Finding or observing a rare or uncommon plant or animal is one of a naturalist’s greatest joys. I for one have spent many hours searching high and low for rare birds, herps, and insects. However, many times rarities turn up when you don’t expect them and sometimes they are found by the unsuspecting.

One such find happened on September 28, 2009 at the Delaware Nature Society’s Burrows Run Preserve in northern Delaware. During the “Life of the Monarch Butterfly” program being taught that morning to students from The Pilot School, one of the children netted a butterfly that looked unusual to the Teacher-Naturalists (TNs) leading the program. One of these TNs, my wife Amy, realized that she had never seen this type of butterfly before and decided to keep it in the collecting jar until she could make a positive identification. Moments after the school group left the preserve, Amy and fellow TN Judi VanderWerff were able to match the butterfly to one in Elton Woodbury’s Butterflies of Delmarva field guide. And sure enough, it was a butterfly very rarely encountered in our area, called a Milbert’s Tortoiseshell Nymphalis milberti. This handsome butterfly is mostly dark on the upperside except for a wide, bright orange band near the outer edge of the wings. It typically ranges well north of Delaware, usually in the mountains, and also in the western U.S.. Considered a stray in the mid-Atlantic region, this individual possibly was blown down from the Appalachian Mountains. This great find brings the total number of butterfly species found at the Burrows Run Preserve to fifty-four. So stay alert and you may just be the one to find the next rare critter in our area!