Monday, July 31, 2017

Pupa on a Silk Rope


On a sunny day in March we went on a long slow walk with Nels Holmberg looking at bryophytes (mosses and liverworts).  Slowing down and getting on my knees gave me a chance to see things like this half inch pupa case dangling on silk strands from a dead branch just above the ground.  It looked like it was hanging from the remnants of a spider nest.  I took it home and waited to see what might emerge.

On May 26 I found this wasp with the empty pupa case.  It had crawled out over the prior week and had a lonely death, never having found love.  After a lot of searching I sent it to Bugguide where it was identified as Acrotaphus wiltii.  This distinctive beauty is "a parasite of the arabesque orb weaver, Neoscona arabesca. The wasp stings the spider to briefly paralyze it while she lays a single egg on it. The larva is an external parasite." (Eric Eaton in Bugguide)

Female A. wiltii with ovipositor - Betsy Betros
This explains the silk rope that the pupa was dangling from.  After the larva had killed the spider it pupated and was suspended from the spider's web and the silk was twisted into a tangled cable over time.*  It survived the winter hanging close to the ground.  The wasp would normally emerge and search a mate.  The female would then search out a tiny spider and lay the fatal egg.  The larva would then cling onto the spider, feeding on it. 

Like most other Ichneumon wasps, she comes equipped with a dangerous looking but harmless ovipositor, that is harmless to us but not to the right brand of spider.  There is a bit of irony in the fearsome tailpiece that can paralyze a novice with fear.  The stingers of hymenoptera (wasps, bees, etc.) are actually modified ovipositors, now producing painful venom which can paralyze prey, such as spiders, that a wasp can take back to store as food for its emerging larva.



*Charley Eiseman has a set of photos in his Bugtracks Blog showing the larva with its spider victim before and after pupating.

Friday, July 28, 2017

Potter and Mason Wasps

Potter wasp - Monobia quadridens - female
This wasp spent a long time around our deck, crawling over the furniture and even the rim of my coffee cup.  After a long internet search, I settled on Euodynerus bidens, a potter wasp.  Two hours later, Bugguide corrected me with an ID of a Four-toothed Mason Wasp (Monobia quadridens).  There was some solace in the comment that they are almost identical, the main difference being a small white spot on the first abdominal segment and on the temples behind the eyes.  The marked similarity is even more remarkable; it developed independently as they are in separate genera.

Potter wasp nest - REK
Both of these wasps are in the Eumeninae family of potter and mason wasps. M. Quadridens is much more common compared to E. bidens.  It is usually found around open areas on flowers and the adult feeds on nectar.  The female collects caterpillars of tiny moths (microlepidoptera) such as grass moths and leaf roller moths.  She will find holes in wood or hollow stems, lay an egg in it and provision it with a caterpillar paralyzed by her sting before partitioning it off with mud, thus the name mason wasp.  The common name of mason refers to these mud walls.  A few species called potter wasps make their artistic
pottery out of mud.

Four-toothed Mason Wasp (Monobia quadridens)
This is our second encounter with M. quadridens.  Last year one was spotted at our cabin, preparing a nest in a carpenter bee hole.  They commonly use these and if occupied by the bee they will kill the bee, eggs, larvae and even pupae.  Bug Eric explains that they make an empty chamber between each egg chamber, presumably to convince predators that no one is home.  They have two broods a year, the fall class over wintering as pupae.
Home Sweet Home - REK
As they obtain their nectar, they also serve as important pollinators.  The female can sting if you grab it but is not aggressive like its look-alike baldfaced hornet.  Interestingly, the male doesn't have a stinger but can "sting" with the tip of its abdomen, a quick pain with no venom.  Over all they are good neighbors to have around your garden.  You can encourage them by making nesting sites.  Carl and Jessie Haworth have been doing this for some time with fancier designs than mine above.

And finally, where does the name Four-toothed Mason Wasp come from?  Sorry, nobody apparently knows or is talking.
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  • Bug Lady discusses the research on the nest building for "naked" larva which don't spin a cocoon.
  • As always, Bug Eric explains a lot more of the mechanics of their nests.  He suggests this video for more details.

Wednesday, July 26, 2017

Wool-sower Gall and Friends



Our friend Brandon Butler asked me if I hunt.  I initially said no, then realized that I hunt almost daily, I just don't shoot.  Sometimes I eat my finds (mushrooms), other times I photograph my prey and put them under the microscope.  I usually "catch and release" when possible but many of my prey are larvae that won't survive or occasionally die from chilling for photographing or saved as specimens.  I love the hunt.

Early summer is a great time for gall hunting.  As the leaves and buds are coming out, it is easy to spot the various oak galls which are frequently at their most colorful.  A few weeks later they are hidden in the leaves and require lots of patience to sneak up on them.  They can be very evasive, requiring lots of time to find a specimen I flagged just a week before.  This Wool Sower Gall was an excellent example.  It was the size of the tip of my thumb, obvious in the photograph but hard to recapture in the foliage.

The most distinctive oak galls are produced by  Cynipid (sin-a-pid) gall wasps.  These wasps are from 1-8 mm in length and many have a distinct hump on the back.  They lay their eggs on a specific plant and the eggs hatch as tiny larvae whose secretions cause the plant to form a gall around them.  The gall in turn provides both protection and nutrition.  How it does it remains a mystery.  Each species produces a distinctive gall and most are identified by their gall rather than their appearance.
Capsules with a larva - REK

The Wool Sower Gall (WSG) is an excellent example to study, colorful and yet infrequent enough to be elusive.  The gall looks like a cotton ball that sometimes has distinctive pink spots.  It is also called an Oak Seed gall, due to the seed-like appearance of the early larva capsules inside the gall.  The gall is produced by the secretions of the grubs of a tiny gall wasp, Callirhytis seminator.  Unlike the more common Oak Apple Gall which houses a single larva, these galls contain lots of "seeds", each containing a wasp larva.

Seed-like capsule opened to show larva - REK
After splitting one open I photographed the larvae inside.  Each lives on the nutrition produced by the oak, a special blend of sauce and spices created especially for its species.  Ordinarily it will live here until mid summer when it will emerge, but my razor blade has ended its chance to reach maturity.

Not Callirhytis seminator - REK
C seminator - Ces.ncsu.edu
The gall at the top of the page was left on the tree until it started to dry up.  I kept it in a ziplock bag for 10 days until the first wasp emerged.  It looked like a tiny black spot on the wall of the bag, measuring only 2.5 mm under the microscope.  I would have assumed under the circumstances that it would be C. seminator  but even I could tell at a glance that it isn't.  My first clue was her ovipositor which is longer than the wasp's body.

I sent pictures in to Bugguide and the response was even more interesting.  Ross Hill responded rapidly, identifying it as Torymus tubicola"a known parasitoid of Callirhytis seminator."  He sent it on to Eric Grissell who confirmed the ID.  There are over 400 species Torymus species world wide and it takes an expert to get an identification to species level.  I didn't expect to find much more information on this species, but finally ran across this blog by who else but Eric Eaton, aka Bug Eric.  Charlie Eiseman also reported on several he raised.

Not C. seminator but still a cool find!
Meanwhile, I am continuing my attempt to photograph C. seminator when it emerges from its custom built gall.  I think it is incredibly cool that a 2.5 mm wasp can lay an egg on a mighty white oak twig, the larva then produces enzymes, hormones or who knows what combination that causes the oak to create specially designed housing for it to grow up in, protected from the elements.  There is a master's thesis in this but better yet a source of wonder for any kid like me that finds one when out hunting.

Monday, July 24, 2017

Black Swallowtail

 Chrysalides are like a box of chocolates, you never know what you might get. (With thanks to Forest Gump.)

This has been the big year for Black Swallowtails.  For us it began when Barb was pulling the flowering tops off of invasive poison hemlock.  She brought them home in a black plastic bag and out crawled a caterpillar.  We put it in a plastic box and it quickly formed the pupa below.


Then she started finding them on our fennel and dill in the gardens at the creek and in Springfield.  She had been raising these plants in our gardens for years without finding them and now they are everywhere!  We have them in all stages now and are seeing the results.  And they aren't always what you expect!

Starting to pupate
Pupating on a chrysalis













One caterpillar even bypassed all the twigs and branches left for it and attached to another chrysalis to pupate.

While Black Swallowtails evolved in North America eating a number of plants in the carrot family that I don't recognize, they have learned to love imported food.  This includes a lot of of our herbs like dill, fennel, caraway and parsley.  They also eat some imports we wish had not made the trip like poison hemlock and its benign cousin Queen Anne's lace.


This is the result we expected, a gorgeous Black Swallowtail.  The various black swallowtails are hard to separate, especially on the wing.  The Black and Spicebush are especially close with two rows of orange spots on the underwing but this side by side comparison may help.

Newly emerged and hanging on fennel.
You won't have any problem separating this unexpected result for another chrysalis.  We were startled one morning to find it in the cage with the newly emerged swallowtail above.  This is a Trogus wasp, a parasitoid that lays its egg on a butterfly caterpillar.  The larva will live in the caterpillar, eating away inside while leaving just enough for the caterpillar to survive and pupate.  It then finishes off its host before emerging.  I suspect it was as surprised as we were to meet that morning.  Meet Trogus pennator.  I knew it looked familiar and finally realized that we had written a blog about Chris Barnhart's finding in 2011.


This Ichneumon wasp specializes in swallowtail butterflies for its eggs.  Lots of the pictures show it with Black Swallowtails but it avoids a look alike Pipevine Swallowtail due to its chemical toxins.  Looking back at the exuvial chrysalis we realized that this wasp had parasitized the larva that Barb found on our hated invasive poison hemlock.  We have to train them next time save the herbs.


Thursday, July 20, 2017

Life and Death on the Prairies

Faking a broken wing

By Becky Swearingen, MN
 I love the prairies, as anyone who follows my adventures knows. Part of the mystery is that nature is not always pretty and not always kind.

I had been watching a Killdeer nest at Talbot Conservation Area for several weeks, alerted to its presence by the adult's broken wing displays. When you get too close, the adult leads you away by hopping along, dragging a wing in a pitiful fashion, until you are some distance away from the nest. It usually will flash its bright tail feathers to be sure you are following, then may fly rapidly away, looking over its shoulder and laughing.
Changing of the guard, shading the nest in left foreground
I was anxious to follow the hatching of the eggs and watch the little Killdeer skitter around looking for food. I looked and looked for the nest and finally found it in plain sight. As usual, the parents had just scraped out a little area in the gravel by the parking lot and laid the eggs in it. The parents were vigilant about guarding the nest. Here they are switching off duties, which, because of the heat actually involved shading them more than sitting on them.
Parent shading the three eggs
I was excited when a friend texted me one morning that he was at Talbot and the eggs had hatched. He was watching two of the chicks as they ran around exploring and feeding. I arrived and there they were – two Killdeer chicks with their parents.
Find the chick
But where was the third chick? When I finally located it, I thought it was strange that it was separated from its parents and siblings. It would walk a little bit and then lie down in the grass.


As I was watching it I was sitting in my car and my friend was standing next to the car. The chick then did the oddest thing. It ran very purposefully toward my car and got under a tire and lay down.
A "tire-d" little chick
Looking for shade, shelter or just suicidal?  I knew that wasn’t the safest location for it, so I got out of my car and gently picked it up to move it back into the grass and closer to its parents.  I had noticed that both the parents and the two other chicks had disappeared. The parents had taken them into the taller grass. I set the chick down in the grass closer to where I had seen the parents, expecting them to return at any moment to retrieve the baby.

Killdeer parents are very attentive. We waited for several minutes and the parents never returned. I decided to go check on the chick and when I did, I discovered it was dead. I think the parents had determined that this little one was struggling and abandoned it to focus their energies on the two healthier chicks. This one appeared to be smaller and less energetic than the two other chicks.

As I left this area, I stopped by a second Killdeer nest I knew of. That mother had been sitting on three eggs just a few days previously. When I got to her next, I noticed that she was now down to two eggs. Life on the prairies seems so serene, but it is a daily struggle for the animals who inhabit it.

On a happier note, after I had driven around the Lockwood area for a while I decided to stop by Talbot on the way home to check on the Killdeer family. As I mentioned, they last time I saw them the parents had moved them into the taller grass, so I wasn’t sure I would be able to see them. I was so happy when I found them out in the open by the water with the parents. The two surviving chicks were busy exploring their new world.
Mother was close by supervising them. Life moves on. I hope for the best for these two little ones.
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Editor's note
 Killdeer chicks are precocial, meaning that they exit the egg with eyes open and their track shoes on.  For more on how this happens and how egg in a nest laid days apart all hatch the same day, see this  Birdwatching.com article.

Monday, July 17, 2017

Bleeding Spider

 

I received this gift of a spider to identify.  There had been two of them, possibly mating only this one couldn't get away.  It was in a jar and was having trouble getting around with a noticeable "limp," dragging its two front legs.  We couldn't decide if it was trauma related or possibly a male victim of a female's post-mating snacking.

Big eyes on top, four below
Click to enlarge
The first step in spider identification is to look into their eyes.  Getting one to sit still for a facial photograph can be a chore but this one wasn't moving well so I got a full frontal view.  The arrangement of eyes can be diagnostic of the spider's family using tables such as the one on Spiders.us.  The slightly concave arrangement of the 4 lower eyes suggested Zoropsid family but they don't occur in the Midwest so I was left with the possibility of a saggy Wolf Spider whose eye pattern is usually more convex.

Of more interest to me was the clear fluid which was on the table.  Close up I could see blebs on a leg and just behind the chelicera on the right side of the cephalothorax.  My friend didn't think it was injured during the capture so this likely was from the other spider.  I suspect that these were drops of spider hemolymph, i.e. spider blood.  This gets a bit complicated so stick with me (or move on to cat videos on Youtube).

Spider's blood is different from  mammal's blood.* In humans and other mammals the oxygen is bound to hemoglobin, a molecule that contains iron and gives the red color to blood cells. In spiders and some other arthropods, such as crustaceans as well as most mollusks, the oxygen is bound to a different molecule called hemocyanin that contains copper instead of iron.  The hemocyanins are proteins in the lymph rather than in blood cells, colorless in the reduced or deoxygenated state while oxidized copper gives a blue/green color to the oxygenated blood. Therefore spiders have clear to pale "blue" blood.

Spider's respiration is far different from insects.  This from the American Tarantula Society explains it far better than I can:
"The exchange of O2 and CO2 in insects is accomplished by an often complex system of air tubes, made up of trachea and the smaller tracheoles. The air tubes suffuse through the body in close contact with insect tissues. Hemolymph components are not needed to assist in gaseous exchange between the tissues and the air tubes. This point is driven home when you consider what happens with some insects, such as certain grasshopper species. When on the move, the blood is apparently being circulated around the body sufficiently, because the heart stops beating. The swishing around of the blood caused by movement is enough for the hemolymph to fulfill its function, which is largely distribution of nutrients, water, and the movement of wastes to the malpighian tubules for removal (roughly the insect equivalent of kidneys). The heart begins beating again when the insect stops moving."
Most spiders and insects are so small that any blood produced by squishing them is never noticed.  The exception is from an insect that is sucking your blood.  The take away is if it is red after you swat it, it was your blood!

Spider blood  http://askascientist.nz/z158
Spider respiration  http://atshq.org/articles/Respiration.pdf
*  Findaspider.org
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A recent article caught my attention by mentioning that most of us have fewer bugs splatting on our windshield than we did 20 years ago.  For those kids reading this, a 30 mile car trip in the "old days" left the windshield covered with spattered insect bodies.  Is something more serious going on?  Read this on Where have all the insects gone?

Saturday, July 15, 2017

Innocent White Moth


Walking a trail on an overcast day I spotted a small white moth on a leaf.  After a quick photograph it started to drizzle and I clipped off the branch to inspect later.  The next morning the moth hadn't moved until I nudged it but it still hung on tight.  There was a fuzzy white patch on the underside of the leaf and a smaller one under the moth when I bent the leaf.  I could see a mass of eggs and surprisingly the moth didn't fly off.  After photographing it I kept it for a week with the now dead moth clinging to the leaf.


Eggs in underside of leaf

This is the Fall Webworm Moth, Hyphantria cunea.  WAIT!   Before you hit the delete remembering those hated masses of silk on your tree during their big year in 2016, follow along to know thine enemy.  After mating H. cunea lays around 400 eggs on the underside of a leaf.  The eggs are bright green in many pictures but also described as "hair-covered masses of several hundred each" in others.  The hair comes from the female's body.

The female typically clings to the leaf until she dies, in this case covering her last batch of eggs.  I checked the leaf daily and on day 8 a few caterpillars emerged.  these were black-headed, typical of the spring hatch.

Emerging caterpillar
Empty egg cases













After filming them, I took the now dry crisp leaf out to a small elm tree and clipped it onto a fresh leaf.  The next morning they were crawling over a portion of the new leaf, eating the top green surface only.  You can see one emerge in this video.
Leaving the eggs
Skeletonized leaf - University of Florida
The larger next instar will eat both surfaces of the leaf leaving the structure of the leaf with no surface cells.  The final instar completely skeletonizes the leaf, eventually leaving only major veins, a view hidden by the ugly webs we all hate.

Dinner for the first instars







More on the subject is at this University of Florida link.

Thursday, July 13, 2017

Bathroom Fly

Bathroom Fly - Clogmia albipunctata - REK
Side view - REK
In line with our policy of presenting the good, the bad and the ugly, here comes old ugly.  We have noted these tiny flies in our bathroom at the creek house for years.  They are very hard to photograph, measuring only 2mm (less than 1/10").  Bathroom lighting is poor and when I get the camera lens close they fly off.  I caught several in a kill jar which yields only twisted specimens.  That said, I finally got a couple of "good enough" photographs to identify them.

C. albipunctata on the wall - REK
Once again, using my post-retirement entomological training, I Googled "Bathroom fly" and came up with a rapid answer of Clogmia albipunctata, aka bathroom fly.  They are in the Moth Fly family, Psychodinae.  They have hairs on their wings which will shed like scales and long segmented antennae.  Our C. albipunctata (white spotted) is the only member of its genus in North America and has distinctive white antennae and white spots on the edges of wings and tips of leg segments.  It is a common synanthropic species throughout the temperate and semi-temperate world.
C. albipunctata larvae - Ashley Bradford

C. albipunctata pupa  - Ashley Bradford
A synanthrop, Greek syn-, "together with" + anthro, "man," is a plant or animal species living selectively near humans and prospering when they find a stable habitat with food, protection and in more recent years a relatively stable temperature range.  These range from house flies, silverfish and cockroaches up to larger species such as house sparrows, pigeons and brown rats.  Some species such as pigeons can no longer make a living without us.  The moth fly family is now found on all continents except Antarctica, probably transported by the movement of human populations.

Until we came along, C. albipunctata probably lived in moist decaying plant and animal matter.  Societies have brought garbage collections, water containers like rain barrels and fire pits, air conditioners and cooling towers and clogged roof drain pipes.  Better yet are all the kitchen and bathroom drains with traps that can hold the gelatinous egg masses.  These are resistant to flushing, hot water, soap and many drain disinfectants and cleaners.

On hatching the larvae feed on algae, bacteria, fungi, microorganisms, and are a welcome addition to wastewater treatment plants.  The cycle from egg to adult is 7 to 28 days with more of the gory details here.  Ashley Bradford has a great series of their life cycle at this Bugguide link and Duke.edu has good closeups of the adult.

Wikipedia has good suggestions for control of our population.  Our source is likely the shower drain and I will collect specimens with a clear glass jar inverted over it.  It will be getting special attention, once I have been able to collect larvae  and possibly eggs to raise.  (Editor's note - "GROAN!!)

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Since the above was written, I failed to trap specimens from the shower and sink drains.  Ashley suggested the grout around the shower.  The tree farm house here is "rustic", a polite way to say poorly built with the bathroom partially below ground level and always damp. I suspect there are tiny little signs in the foundation cracks outside that say, For a good time big boy, come on in here. Free food and fermented beverages!