Fluttering

Fluttering

August 2016

One day in early August, we had a classic summer storm. When I walked onto our screen porch that evening, it was all a-flutter – I mean excessively a-flutter.

Moths in just one corner of the porch

It is not at all unusual to find various fluttering and buzzing things inside the porch. In fact, it's a good place to get a close look at various kinds of insets and learn to identify them.

Sometimes I find them lifeless on a sill or the floor after they have buzzed around too long from frustration, not knowing the way out. The large Carpenter Bees (which look a lot like Bumblebees, but less fuzzy) are the worst ones, their carcasses littering the floor at times.

Sometimes I manage to catch and release insects, particularly butterflies. However, the butterflies are best at finding their way back out.

This poor thing had wings that had seen better days, but I think it's a male Tawny Emperor (Asterocampa clyton clyton.)

I'm pretty sure this is a Silver-Spotted Skipper (Epargyreus clarus clarus.)

Here's what I found out on this one: it's a day-flying moth called Grape Leaffolder Moth: Superfamily Pyraloidea; Family Crambidae (Crambid Snout Moths); Subfamily Spilomelinae; Genus Desmia. The scientific name is Desmia funeralis (I'd like to know where the "funeral" part comes from - maybe the way it looks) and it has been know also as D. maculalis. The larvae feed on Evening-Primrose, Redbud and both domestic and wild grapes. We have plenty of all but the domestic grapes. This one is a male, evidenced by the distinct, appendaged antennae.

A Black Swallowtail (Papilio polyxenes asterius - male?) on Garlic Chive blossoms just outside the porch.

Once in a great while a bird finds its way in, frantically dashing throughout the porch, calling in alarm, grasping the screens with its tiny feet. I must chase it out quickly (usually by gently guiding it with a broom) because the cats get very interested.

Once a year, hordes of Asian Ladybugs congregate in the upper corners of the porch walls, ceiling and screens, and eventually disappear.

Other than the ladybugs, the great August congregation of smallish, dark moths was the largest mass insect gathering we'd had on the porch. Where did they come from all of a sudden? Why so many? What were they?

I thought perhaps they were taking shelter from the storm and that most would soon leave. But, they stuck around for the rest of their little moth lives.

I looked closely at them and took photos. Here are the main characteristics I observed:

–        at rest, they held their wings out in a flat, triangular shape

–        they all had distinctive  long, dark “snouts”

–        they were various shades of dull brown and gray, with some pattern on the wings (particularly the forewings) – I surmised that they would blend in well with tree bark

–        some were a little larger than others

–        there were some furry looking patches on their bodies.

I tried consulting my Peterson Guide to Eastern Moths, but it was hard to track it down there. I found groups that it must belong to, but some of the photo pages were in black and white, and there were so many moths to a page, with so many looking alike.

I wasn't sure how to approach this on the internet, but I knew who to contact – someone who is really into bugs and who knows just the right resources to go to – my county Extension Educator.

I sent her an email with three photos. It didn't take her long to respond with a link and the message, “this is the closest I could get.” Well, it looked to me that the Green Cloverworm moth (Hypena scabra) was as close as anyone could get. The link described my moths perfectly and the photo was identical. Later, she sent me another email saying that she had it verified.

She must have been very intrigued by this critter because it became the next topic of her local newspaper column.

I was then able to pin-point the moth in my Peterson moths guide. But, my guide was published in 1984! Things change in classification, so I also searched the internet. My book had it under the old name, Plathypena scabra, but it had recently been moved to the Genus Hypena.

The world of classification, especially with more recent research using DNA, is a very picky world. So, other things had changed besides the genus. It is still, of course, under the Order Lepidoptera, which are the scaly-winged insects – butterflies and moths. But that was the only thing that hadn't changed. I had to do some teasing-out of terms to get to the current status. My 1984 book has the Green Cloverworm in Family Noctuidae, under Superfamily Noctuidae. Well, it has gotten more complicated. I now find that it's in the Subfamily Hypeninae (snout moths) of the Family Erebidae, which is under the Superfamily Noctuoidea. Confused yet??

Order: Lepidoptera (butterflies and moths)

     Superfamily: Noctuoidea

          Family: Erebidae

               Subfamily: Hypeninae (snout moths)

                    Genus: Hypena

                         Species: H. scabra (Green Cloverworm)

Family Erebidae, formerly a subfamily of Noctuidae, is among the largest families in Superfamily Noctuoidea. It includes the underwings, tigers, tussocks, owlets, and our snout moths, among many others. Family Erebidae has 18 subfamilies – well, the last I checked – including our moth's Subfamily Hypeninae. Whew!

The confusion is not only in trying to reconcile between an old guide book and the internet. There are sites on the internet that still have the Green Cloverworm under Noctuidae! To change that would mean changing information on hundreds of pages on the web! So, you are lucky if you stumble across a correction or refutation, as I did. One said, “A very large portion of the Noctuidae was moved to Erebidae back in 2006 ...”, but, it goes on with much more detail. 

https://en.wikipedia.org/wiki/Talk:Noctuidae

Well, let's leave all that behind for now, shall we? And get on to other things.

Such as … why the “snout”?

It turns out that the “snout” is formed by the “labial palps” and the “proboscis”. In this group, the labial palps are exceptionally long. What are “labial palps”? According to the glossary in my moths book, they are “a pair of segmented … appendages that project forward and usually curve upward from the lower part of the head.” They are used for sensing. Between them is the proboscis, a sort of coiled tongue that is extended to take in water and food. Many of us have watched a butterfly on a flower which has uncoiled its proboscis, probing the flower for nectar.

I didn't find any mention of the color and pattern on the wings being camouflage on tree bark, but it is the particular arrangement of lines and dots that identifies a species of moth in this group. There is  some variation in coloring among these moths. I did find mention of body “hairiness.” 

In my book, the Green Cloverworm is referred to as part of the “Deltoid Noctuids”, referring to that triangular shape of the wings at rest. They do look like tiny deltoid aircraft ready to taxi and take off. Maybe they are the inspiration for this:

Canarded Deltoid Main Wing Aircraft patent:

https://www.google.com/search?q=aircraft+with+deltoid+shape&espv=2&biw=1455&bih=726&tbm=isch&imgil=YdFi-9nMoKB7RM%253A%253BNypku0UydfZiVM%253Bhttps%25253A%25252F%25252Fwww.google.ch%25252Fpatents%25252FUS20100224735&source=iu&pf=m&fir=YdFi-9nMoKB7RM%253A%252CNypku0UydfZiVM%252C_&usg=__nMWTNPvrDK8105d9V_PzKSkl314%3D&dpr=1.1&ved=0ahUKEwjZo7Koyd3OAhVCTSYKHTPfBXoQyjcIKw&ei=bmu_V9m0NcKamQGzvpfQBw#imgrc=YdFi-9nMoKB7RM%3A 

https://www.google.com/patents/US7854409

If you are into UFO's, they also resemble the mysterious “Dark Triangles”:

http://www.ufoevidence.org/topics/triangles.htm

But, why were there so many moths all at once?

That goes back to the larva or, rather, the larval food source. The Green Cloverworm larva is a light green caterpillar with a narrow white stripe along each side of its body. It resembles a looper, except it has four pairs of prolegs instead of the looper's three pair.

As the name implies, this “worm” (really a caterpillar) prefers clover. We have plenty of clover on our property, and all around. It also is common in soybeans, and this year we are surrounded by soybean fields, including our field near the house. In fact, the Green Cloverworm larva is a “soybean defoliator.” However, despite that strong-sounding tag they don't do enough damage to be a true agricultural pest. This is because their population is checked by their susceptibility to parasites and pathogens. The Purdue Extension Entomology web site even describes for us how parasitized and diseased Green Cloverworm larvae look (see list of links at end of article.)

Their population is also checked by predators. The North Carolina State Extension Cooperative Extension Integrated Pest Management web site says, “Many entomologists consider the green cloverworm a valuable food source for beneficial insects ...”

What else do they eat, besides the clover and soybeans that are so abundant at our place this year? Here's a list of other foods (leaves) that exist somewhere on our property:

–        beans

–        peas

–        locust trees

–        ragweed

–        raspberries

–        strawberries

–        corn

–        cherry tree

–        elm tree

–        hackberry tree

–        poplar tree

–        willow tree

Abundant food source = abundant larvae = abundant moths.

Here are other food sources I found listed, not currently on our property:

–        False Indigo

–        Alfalfa (we used to raise alfalfa hay, so there may still be some out there, or some on property nearby)

–        New Jersey Tea.

–        Birch tree

They like the leaves of any legumes, and we have more of those than are listed, such as southern peas, vetch, etc.

A curious thing some of the sites describe is the reaction of larvae when disturbed which will display “a brief jumping, flopping activity” or, better yet, “thrashes violently when disturbed.” I must find one and test this.

The Bugguide.com site tells us that the moths fly from March to November but are most common in late summer and fall. That makes sense. I wonder if we'll yet have another invasion? They also say there are at least three generations per year.

The moth lays a light green, hemispherical egg on a host plant leaf, about 0.5 mm in diameter. The larva hatches out yellow and starts munching away, turning light green, and eventually growing to about 30.5  mm long, if it escapes predators and disease. The successful larva, after feeding for about four weeks, drops to the ground and burrows into the litter or soil. There it becomes a dark brown pupa about 13 mm long. After about ten days, the moth emerges, pumps out its deltoid wings and takes off – many of them to our porch this year. They can overwinter as either pupae or adult moths. (facts from the North Carolina Integrated Pest Management web site)

And, so, here they were, a horde of them, fluttering away on the screens and walls. They began to disperse, but often into the house, as they are attracted to light. If I had to open the door to the house, I'd let in about fifteen, and more than that at night.

Soon they were all over the house – little dark brown deltoids dotting the pale living room carpet (sometimes turning slowly around as if getting ready to taxi to the runway,) the walls, the windows and window sills – just everywhere. While I was working at the computer, one zoomed to my head and landed briefly on my hair. We are too busy in summer to be chasing moths, and there were too many of them, so we just let them live out their lives. Hopefully some made it back outside where they could lay eggs on larval food sources, which they cannot find in our house. I have seen some flitting over the grass outside in the sun. They are supposed to be nocturnal, but I'm not sure I believe that.

Predictably, there came a time when I frequently swept up their inert forms from windowsills, kitchen sink, room corners, shelves, etc., and sent them to the compost.

There is probably another generation of larvae out there, mostly in the still bright green soybean field, munching away. Though we always have plenty of their food sources here, there will be much less next year when the crop rotation goes back to corn.  Oh, wait a minute – corn is on the list, too.

We'll see what turns up then.

Three Green Cloverworm moths showing variation in coloring

*********************************************************************************

Eastern Moths (Peterson Field Guides); Charles V. Covell, Jr.; Houghton Mifflin Company; 1984.

Bug Guide

bugguide.net/node/view/9540

Moth Photographers Group

mothphotographersgroup.msstate.edu/species.php?hodges=8465

Purdue Extension Entomology

https://extension.entm.purdue.edu/fieldcropspm/insects/green-cloverworm.php

North Carolina State/A+T State University Cooperative Extension – Integrated Pest Management

https://ipm.ncsu.edu/AG271/soybeans/green_cloverworm.html

Wikipedia

https://en.wikipedia.org/wiki/Hypena_scabra