Friday, April 19, 2019

Spring Beauty Colors


On our first Wildflower Walk of 2019, the spring beauty, Claytonia virginica, were carpeting the forest floor along the Mail Trace Road.  These are tiny flowers, not particularly striking unless you bend down for a close look.

They have tiny streaks of color called nectar guides.  These are paths like a painted stripe leading to the nectary where the flower's pollen is waiting to be spread.  The nectary contains the rewards for the pollinator, sweet nectar, oils, resins, and scents and sometimes the pollen itself.  For the pollinator it is about reward, for the plant it is pure sex.

What was striking was the variety of colors in the petals.  They ranged from an almost pure white with faint pink streaks to the background white almost blotted out by the wide deep purple
nectar guides, converting it to what almost looks like a different species.  There was soon a lot of discussion of why the different colors side by side.  Could it be the time of blooming or the temperature variations in the soil?

It turns out that others have asked this same question.   A study by Frank M. Frey out of Indiana University found that the differences were genetic, controlled by two different compounds and created 4 distinct color morphs ranging from all white to mostly crimson.  The results are simplified to my level in this description from Indefenseofplants.com.

"...pollinators, which for Claytonia are solitary bees, do, in fact, prefer crimson color morphs. This helps to explain the greater number of crimson colored flowers in any given area because the more pollinator visits, the higher overall fitness for that plant. What it does not explain though, is why white morphs exist in the population at all."  
"The flavonols that produce white pigmentation also beef up the plants defenses. Frey found that white colored flowers experienced significantly less predation than crimson flowers. Herbivory has serious consequences for Claytonia and plants that receive high levels of herbivore damage are far more likely to die. Because of this, white morphs, even with significantly less reproductive fitness, are able to maintain themselves in any given population."

Monday, April 15, 2019

Living Room Ants


We walked into our living room at the creek and found these ants clustered around a small black fragment. We were conflicted by the problem of "securing our border" (i.e. the front door sill) while removing the ant migrants safely. We tried brushing them, considered baiting and finally used extreme measures on the remaining few while two escaped under the sofa.

James Trager identified the ants as eastern black carpenter ants Camponotus pennsylvanicus.  Its claim to fame is that it was the first North American ant to be described.  It is ubiquitous east of the Rockies and can be very destructive when out of its natural woodland habitat, chewing wood in our structures. They only eat dead wood that has some degree of softening by rot.  Ants might argue that they were here long before we were and the conflict comes from humans and their wood dwellings that have encroached on the ants' territory.

Munching on a spider head
"C. pennsylvanicus can be distinguished from other carpenter ant species by the dull black color of the head and body, and by whitish or yellowish hairs on the abdomen."  This is a highly social species that lives in trees and rotting logs in the forest. Colonies can contain over a thousand ants, and can occasionally produce a crackling sound. The workers forage for food and can tend aphids, harvesting their honeydew for the colony. They also feed on dead insects like our specimen above. Wikipedia

Now we are concerned about those two ants that are isolated and lonely under the sofa. There is scientific evidence in this study that a related species, Camponotus fellah, have a shortened life span when they are isolated and presumably depressed.  Isolated ants lived only six days, whereas group-living ants lived up to ten times as long (averaging 66 days of life).
"Although isolated ants ingested the same amount of food as grouped ants, they retained food in the crop, hence preventing its use as an energy source. Moreover, the difference in life span between single and grouped individuals vanished when ants were not fed. This study thus underlines the role of social interactions as key regulators of energy balance, which ultimately affects aging and health in a highly social organism." *  Lonely Ants Die Young 
Dolomedes tenebrosus - James Trager
I tentatively identified the fragment of the ants' victim as remains of a Dolmedes sp spider.  The eye arrangement is distinctive with the lower four eyes curving upward like a smile, unlike the frown of other members of the Pisauridae family of nursery web spiders.  They are so named because they carry their egg sacs in their jaws.  Coincidentally, James reminded me that he had previously shared the photograph above with me, taken in our cabin!
"By the way, I took pictures a live Dolomedes tenebrosus when I was in your cabin. They like the moist woods and riparian sites, and hang out on tree trunks looking like bark. I’ve never found one at the actual water’s edge, where related Pisaurina mira lives."
Meanwhile, I considered forming a support group for the lonely and starving pair of ants under the couch but Barb has convinced me that I am suffering from excessive anthropomorphic thoughts.  If they emerge they will likely be euthanized with her finger. 


* Social isolation causes mortality by disrupting energy homeostasis in ants. 

Behavioral Ecology and Sociobiology.

Wednesday, April 10, 2019

All Natural Breakfast

Indian-meal moth of winter - 9mm     REK
Last month I saw the first flying insect of winter on the creek house bathroom wall.  It was 9mm long and I readily identified it on INaturalist as an Indian-meal moth, Plodia interpunctella.  It occurs on all the continents and is named because it is commonly found in Indian meal, i.e. corn meal.  It is considered the most important pest in stored food products in America and is omnivorous, consuming grain products, seeds, dried fruit, dog food, and spices. (Florida University Entomology)

Intact pupa
The next week I started to pour some crunchy cereal into my bowl for breakfast when I saw something roll out of the bag.  When I was a child in the 1950's breakfast cereals advertised "a toy in every box!"  Now 68 years later this "toy" was "organic" just like the cereal.  It was a well formed 7mm pupa with the future wings visible along the back.

Empty pupa case on a toothpick for scale - REK
We hadn't opened that cereal box for several months, the plastic bag inside was rolled up tight and it was stored in a plastic box with snap on lid. After breakfast I noticed several things clinging to the inside of the clear plastic bag.  These were empty pupa cases the same size as the moth, attached by silk to the clear plastic cereal bag. I picked this one up on a toothpick for photos.

Cereal flake with larvae and lots of frass - REK

After emptying the bag on a plate I sorted through the breakfast cereal with a magnifier. Six of the flakes were packed with extra organic nutrition, not too bad for a nearly full box. Tiny 3mm larvae clinging to them as well as little white eggs and a lot of frass.   Just think, the whole life cycle present in our kitchen!
According to the National Pesticide Information Center (NPIC), the larvae travel away from the food source to pupate, increasing their chances of survival.  They are able to chew their way through plastic and cardboard boxes, probably how they were able to attack our cereal.  The site has an extensive list of foods they can attack including cereal, grains, beans, nuts, flour, dried fruit, birdseed, dry animal food, spices, tea, chocolate, and candies.

If by now you  are getting a little paranoid,  the NPIC also has an extensive list of Control Tips that could keep you busy for a week.  I for one will be eating my cereal a lot faster and maybe not look at it under magnification quite so often.

If you haven't had enough fun yet, you may want to read Bug Eric's suggestions for an indoor bug hunt.

Thursday, April 4, 2019

Bombardiers, True and False


One advantage of country living is that you don't always have to go out to find nature - sometimes it comes in to find you.  Last Friday I saw this ground beetle crossing the living room floor, intent on finding safety under the couch.  It wasn't too happy to end up in the box, but at least it didn't fire its defenses at me.

This is a false bombardier beetle, most likely Galerita bicolor or possibly G. janus.  The two species are both common and similar in appearance.  The head and pronotum shapes are somewhat different, but I don't have the ability to separate them without a key and a lot more knowledge.  My guess is G. bicolor but go to bugguide.net and make your choice.


Galerita are said to be found in forested areas, in or under decaying or rotting timber.  This didn't give me much confidence in our cabin flooring until I found a number of sites recording finding them in houses and basements.  They are carnivorous predators, eating primarily caterpillars and other insects.  I imagine they think they are in a cafeteria in our creek house which is seemingly porous to all invertebrates (and a few vertebrates of rodent-like inclinations).
 

The specimen above was a "boot dissection" - found on the bathroom floor - that shows several key features.  You first see the elytra (hardened wing covers) that have linear grooves.  They protect the membranous wings below which have to be "inflated" with fluid before the beetle can fly.  Because this takes time, flight is not its best strategy when escaping a predator.  Instead it makes like a skunk and puts up a stink, possibly from the glands above, exposed at the tip of the abdomen. 

False bombardier beetles demonstrate that chemical warfare is nothing unique to humans.  It has glands on the abdomen which produce formic acid with a little acetic acid thrown in for good measure.  This produces a noxious odor, discouraging predators and can cause a burning sensation on the skin.  They have two side-by-side glands and nozzles and can selectively spray the side that is being attacked, such as holding a leg with tweezers.  They hold the other side's gland in reserve and can administer another six doses before running dry.

With armament like that, you might ask "then what does a true bombardier beetle have up its abdomen?"  The true bombardier beetles are smaller but don't let that fool you.  Their weapons are much more powerful, with separate chambers holding hydroquinones and hydrogen peroxide, suddenly mixed together with oxidative enzymes just as they are fired.  The chemical reaction heats the spray to near boiling temperature and the gas powers the spray.  To quote the Bug Lady, "drop for drop, the chemical is more potent than skunk spray, and a toad that is sprayed in the mouth gags, sticks out its tongue and rubs it against the ground."

"Just chillin' out."
Like many other insects, these beetles don't like having their picture taken.  Many species will fly away just before you finishing focusing on them.  In this case, Galerita seldom fly but scamper about quickly.  After an hour in the refrigerator slows them down for several minutes there is enough time for taking a portrait.  The insects aren't harmed, escape once they warm up and any goose bumps they have don't show at this magnification.

Thursday, March 28, 2019

I'll Drink to That

Long distance feeding - proboscis of the convolvulus hawk-moth_(Agrius convolvuli)
Snail proboscis - Wikipedia
The last blog discussed the anatomy of the incredible lepidopteran proboscis.  Before we go further, I need to point out some other species which have a proboscis.  Some other animals, including snails, as seen on the right, use long, prehensile proboscis for feeding on a dead fish.  Some other species have a proboscis used for function, beauty or just a good laugh.


Proboscis monkey - Wikipedia
In mammals the elephant trunk wins the function award but there are other famous contenders as well.  Consider Jimmy Durante, a comedian who made a career of poking fun at his nose as in his song Boys with the Proboscis.

Jimmy Durante - Wikipedia


Elephant seal  - Wikipedia















Great spangled fritillary on sweaty head
Some butterflies collect fluids that go beyond gross as described in Blood, Sweat and Tears.  Sweat feeding is not uncommon and some species like the hackberry emperor can be aggressive, landing repeatedly on sweaty surfaces even when brushed away.  I have had several land on me at the same time, evading my net by landing on my head.  Before this makes you feel special, they also feed on dung, mud puddles and animal urine.
Lachryphagy in the Peruvian Amazon  - Phil Torres from Mix
Tear‐feeding (lachryphagous) butterflies and moths can land on a larger animal and essentially puddle around its eye.  They poke their proboscis into the eye to stimulate tear production.  They usually feed on turtles, some mammals and crocodiles (yes, crocodile tears!).  Although lepidoptera don't harvest human tears, there are some bees that do.   "Bees go after the tears instead of sweat since they're 200 times richer in proteins than sweat."

Hematophagous (blood-feeding) moths may get their blood from a wounded surface or by actually piercing the skin.  Calyptra sp. in the Old World all pierce the skin of fruit and 10 species will pierce even tough mammalian skin. Their specialized proboscis has a combination of erectile barbs and tear‐shaped hooks on each galea (half of the proboscis).  "The insect rocks the proboscis from one side to the other, applying pressure until it pierces the skin. It then uses a rocking head motion to drill the tube deeper into the skin. The blood pressure of the victim supplies power to raise hooks on the proboscis to ensure the insect is not easily detached."

Goatweed leafwing butterfly competing with paper wasps - CB
Five Comma Butteflies on a racoon carcass
Goatweed leafwing butterflies are flying in March.  They overwinter as adults, hiding under loose bark, like on shagbark hickory, and emerging on warm days looking to collect sap.  Chris Barnhart describes their thick proboscis that can feed on fruit and they will stick it right under the mandibles of paper wasps which are competing for the same food as in his photograph above.

Happy hour on the deck - Chris Barnhart
Although they may use their wings to bat away competitors, butterflies can also become quite congenial in a puddle of the right kind of fluid as seen above.  This was sap leaking from several spots on a tree and probably fermenting from a yeast infection.  It was a popular hangout for several weeks.  If only all of our human communities could get along like this!

Saturday, March 23, 2019

The Incredible Proboscis


Proboscis in two halves

In the last blog we mentioned that when butterflies emerge from the chrysalis, their proboscises consist of two C-shaped fibers called galeae, which are then united, sealing the halves into a flexible elliptical tube.  So how do the two halves come together to form the functioning tube?  Self-assembly of the Butterfly Proboscis from Clemson describes the process which includes the butterflies' saliva and capillary forces.

No muscle action is required to hold the parts together.  Asknature.org has  technical descriptions of the linkage mechanisms.  This linkage also allows the proboscis to remained coiled without the use of muscle, reducing its energy requirements.

So once the two galeae are sealed together, is that a permanent bond?  I can recall a grade school bully who used to pull the wings off of a butterfly.  In a more scientific version, Suellen Floyd Pometto and colleagues separated the two halves of the proboscis in the name of science.  She performed this on monarch (Danaus plexippus) and painted lady (Vanessa cardui) butterflies, then studied the repair process.  Both species were able to accomplish repair of the proboscis, with variable rates of success.  Those achieving reunion of the galeae had recovery of the coiled resting state and dye studies then confirmed that the restored proboscises functioned normally.

Convolvulus hawk-moth_(Agrius_convolvuli)
That same paper also provides an in depth look into lepidoptera feeding strategies as well as the functions and mechanisms of the proboscis.  It also provides a listing of the 19 different muscles that control the proboscis in slurping up fluids.  The lepidopteran proboscis is a versatile tool to obtain different sources of minerals and food.  Some species are even able to pierce fruit and mammalian skin as discussed in the next blog.

Thursday, March 14, 2019

Winter Chrysalis

Sharon Hughes gave me this pupa at our Master Naturalist meeting on Monday.  Her husband found it hanging from the top of the door frame between the screen door and the front door. It looked like a butterfly chrysalis including a telltale string of silk with which it had suspended itself, waiting to spread its wings with the help of gravity.  Alas, winter had caught it and literally frozen it in time.

Kevin Firth identified it before the ink dried on my email request.  This is a spicebush swallowtail chrysalis, characterized by the two diagnostic anterior 'horns'.  We discussed the caterpillars in last June's blog.      The photographs below from the University of Florida will show how the chrysalis is suspended in nature.  The picture, on the bottom left, gives a better idea of where the wings will emerge and you can even make out the spiracles.


Photo by Donald Hall

Photo by Donald Hall









Since this had been found on a door jam outside of the front door, I had little hope that it would survive the freezing temperatures.  Just in case, I kept it in a bug box to watch.  One afternoon as I walked by the kitchen counter (my wife is a saint) I saw something move out of the corner of my eye. Turning to the box, I lifted the opaque lid and there was the eclosing butterfly. I started a video and then moved it to a larger container with an upright dried twig which it immediately climbed up on. 

You can see the video of its emergence here. Watch closely and you can see it repeatedly extend and curl up its proboscis.  When they emerge, the proboscises of butterflies and moths consist of two C-shaped fibers called galeae, which are united after the insect emerges from the pupa, sealing the halves into a flexible tube.  Here you can see the two halves of the proboscis haven't sealed together yet and the left wing is curved and withered although it is flattening out over time. Eventually it was able to fly around in its aquarium.  The bluish color on the dorsal hindwing confirmed it was a female.

Proboscis in two halves
Empty chrysalis












Proboscis sealed at last
The problem now was that the outside temperature was a high of 30 degrees, dropping to 10 degrees at night.  By putting it in our warm house we had interrupted its winter diapause. With a lifespan of several weeks at best, even if it warmed up she had no nectaring sources, no male available, and no food plants for her eggs. She had no outlet for her biological imperative.  In retrospect, her only extremely long shot at reproduction would have been keeping the chrysalis in the refrigerator until our spicebushes leaf out in 10 weeks.

Of course that is all from an anthropomorphic perspective as no one knows what a butterfly perceives.  With a beautiful and delicate creature, it is natural to empathize and impart our human values.  While it was a hopeless situation for this creature, the only realistic response is to to do what Sharon did and in its memory plant spicebush (Lindera benzoin) and sassafras (Sassafras albidum), its alternate host plant, as well as native plants for nectar.  This spring, carpe diem. Then, like Sharon, you'll be able to say "I grow spicebush so that makes me happy to know the little guys have found my plants"



More on proboscis closure is in this paper.
For much more detail on proboscis function try this source, and may the force be with you. 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4043169/