Spiny Oak Slug

 

 
While I was volunteering at the "Bear Aware" table at MDC's Great Outdoor Days at Bois D'arc CA, a young naturalist named Timothy brought up this caterpillar, one of several like it he had found.  He has been hunting for caterpillars "for a long time" and raises them at home to adulthood.  This degree of sophistication at his age is quite impressive.

His find is a spiny oak slug caterpillar, Euclea delphinii, a colorful creature which comes in a remarkable variety of different colors.  Bright colors are frequently a warning to predators that "I taste bad" or "I can hurt you".  In the case of E. delphinii, it is the latter as those hairy spikes have a fluid that can cause a stinging sensation.

Another color -  Kevin Firth

While many larvae of lepidoptera eat only a limited species of plants, the oak slug relatively omniverous.  It eats " a variety of deciduous trees and shrubs, not limited to: apple, ash, basswood, beech, birch, blueberry, cherry, chestnut, hackberry, hickory, maple, oak, poplar, sycamore and willow," (Wagner, 2005*).

...and another color,  - Jon Rapp

and another! - Bob Barber

There are a number of different species of "stinging caterpillars".  The buck moth and the colorful io silkworm moths have this feature as well as the saddleback caterpillar and the hag moth, coming soon to the blog.  They have in common specialized hairs.

"Stinging caterpillars possess hollow quill-like hairs, connected to poison sacs, that are used as defensive weapons. When these hairs are touched they break through the skin releasing the poison. Reactions can range from a mild itching to the more severe pain, dermatitis, and even intestinal disturbances."  University of Kentucky

Slug moth caterpillars have a unique way of traveling with a wave-like motion,  They can leave a sticky trail not unlike a slug.  This is produced by the suction cups on its eight abdominal segments, replacing the usual prolegs of other caterpillars.

While finding the caterpillars requires diligent searching skills like Timothy's, the cute little (10 mm) moth can be found occasionally on the siding by our deck light.  Once mated, the females lay their eggs on leaves, and generally produce two generations of offspring a year from Missouri on south.

*  If you are interested in caterpillars, Wagner's Caterpillars of Eastern North America is a good place to start.

Little Biter

I was sitting at the "Bear Aware" table at MDC's Great Outdoors Day with Jay Barber, our MDC educator, when he noticed a mild biting sensation on his arm.  Immediately concerned for his comfort, I responded like any Master Naturalist would.  I stopped him from slapping it while I took pictures of it.

Identification proved challenging. Six legs like an insect, no wings, and biting mouth parts suggested an insect larva. It looked a little like a hellgrammite, the aquatic larva of a dobsonfly, while its mouth parts resembled an antlion larva.  At home without my field guides, I turned to entomologist* friends for help.

Kevin Firth came up with a helpful suggestion: "Just raise him to adulthood--you already know what he eats!"  Chris Barnhart identified it as  Neuroptera larva, the family that includes the antlion.  David Bowles then made the ID for me:

"The handsome critter in question is the larva of a green lacewing, order Neuroptera: family Chrysopidae, genus Chrysopa or Chrysoperla (can't tell from photo).  They are predatory on other insects, especially aphids. Maybe this one thought (Jay) was a giant aphid."  Entomologists are a sympathetic bunch.

Chrysopa - Black speckled green lacewing- James Bailey

Robert Lord Zimlich CC

The green lacewings are indeed "handsome".  The delicate pattern of the venation of their wings is important in identifying the species.  Some of the species are named by the color of their eyes.  The golden-eyed lacewing - Chrysopa oculata, on the right has an almost soulful expression.  Clicking on the picture brings out its beautiful coloration.

What's the stink? - Chrysopa nigricornis - Roy Cohutta Brown

Chrysopa species also go by the common name "stinkflies", the entomological version of trash talk like "Your mother smells bad."  This refers to the vile smell that they can release from paired prothoracal glands when handled. 

Chrysoperla_carnea_larva eats an aphid - Wikimedia CC

A green lacewing larva looks like a primitive alligator with ice tongs on its head.  It eats a wide variety of garden pests such as aphids, caterpillars, leaf hoppers and thrips as well as insect eggs and the occasional MDC educator (see Jay above).  It is important to remember that plant pests don't deliberately damage your crops, they are just looking for energy like the rest of us.  It is "eat or be eaten", we just happen to be higher on the food chain.

Eggs - Mainzer Sand cc

Some lacewing adults are predaceous while others feed on honeydew, nectar, and pollen.  Females lay their eggs on plants, attaching them with delicate silken stalks.  The larvae create silken cocoons attached to plants before emerging as adults.  All four stages can survive mild winters.

Chrysopa  larvae are available commercially for aphid control.  You can buy them on the Internet in buckets of 500 to 10,000 for your garden or fields.  Or I can send you Jay and he can attract them for you.

*  I doubt there is an entomologist alive today who has not been conscious that his work is almost wholly unappreciated". L.O. Howard, 1919. - via David Bowles

Special thanks to Jay Barber (Missouri Department of Conservation) who endured "severe pain" while patiently postponing swatting or brushing it off while I took pictures of the larva. He suffered from my pursuit of science, as he always does.

Long-jawed Orb Weavers

 

We were sitting on a pond dock when someone spotted this creature stretched flat along a pole above the water.  Its slender length was dramatic enough that at first glance we weren't sure what kind of insect it was, but after counting its 8 legs we clinched the diagnosis as a spider.

Its posture and the jaws extending way in front of its head is a dead giveaway to its identification.  This is a Long-jawed Orb Weaver (LJO) of the family Tetragnatha (four jaws in Greek).  There are over 1,000 species found world wide, especially in the tropics, but only around 15 species in the US.  Identification of the species requires a specialist with lots of magnification to see parts that you and I could not identify. 

Also called "stretch spiders", LGOs extend their legs when threatened to hide on a blade of grass.  With their long legs and light weight body they are able to run on the surface of the water like a water strider. The third pair of legs which are much shorter are used to cling to grass or other vegetation as they stretch their other longer legs out in front and behind, blending in to the leaf blade.

Spread legs in a box

Even with a pocket camera you can still get decent pictures.  Using only a Panasonic Lumix camera with no specialized equipment you have to get your subject's permission to get up close.  I use a plastic box or container such as a margarine bin with smooth sides to keep the subject from climbing out.  If it is too active, a brief stay in the refrigerator will slow down the action.  You can see it has long jaws extending forward as well as the short third pair of legs.

"My what big jaws you have!"- note right fang.

Although named orbweaver, they are in a different family from the classical Araneidae orbweavers such as the Argiopes we discussed recently.  The Tetragnatha create their orb webs parallel with the surface of the water to pick up prey flying along the surface.  Their typical meal includes species like mayflies that emerge from their aquatic larval form into flying insects or insects that develop in the muddy banks like crane flies.

Front view - Note eyes, chelicerae with folded fangs

Once slowed down, I was able to move it into a different box to get the camera close for macro photographs. The eyes are now visible as raised black spots on the head.  The chelicerae (jaws) look blunt and club shaped, but you can see the fangs folded up along the inner edge.  Like a venomous snake, the Tetragnatha can control the amount of venom they inject.

Lip-locked mating - Youtube

Many female spiders are known to eat their potential suitors or even the male  after after they have mated.   The LJO has an interesting defense against this reproductive hazard.  They grab each others chelericia and holding on tight while the male delivers his vital fluids by using his pedipalps.  This gives a whole new meaning to the term "lip-lock".  You can see a video here but don't expect a lot of action.

More on LJW species at this website.

Beautiful Fungi

Beautiful..... and a slime mold - Trichia decipiens

Fungus and beautiful are two words you may not think belong in the same sentence, but Mark Bower's photography may change your mind.  His updated exhibition of the mushrooms of our area will be on display through the month of October at Burr Oak Nature Center in Kansas City.

Pseudomerulius aureus - Click to enlarge

For those of you who saw his exhibit at the Springfield Conservation Nature Center this year, there is still more to see.  He has added a number of species including some that I think are his best works ever.

Stemontitis sp. (Chocolate Tube Slime) - Click to enlarge

Many of these are tiny slim molds.  The whole set are on line at this Flickr link.  Simply click on the picture and then thumb through them.  At the bottom you can get more information on the species by clicking on "for more information".

Mycena caerulea - Click to enlarge

His other Flickr albums are here.
Mark is a member of the Springfield Plateau Chapter of Missouri Master Naturalists and the Missouri Mycological Society.

Ladies'-tresses Orchids

Photo by Mark Bower

We recently had the pleasure of botanizing at Bull Mills with Doug Ladd of the Nature Conservancy.  While we were standing in the cemetery and I rambled on about the history, Doug turned around and pointed out a few tiny orchids standing above the mowed grass, something that none of us had noticed.  These were slender ladies'-tresses orchids Spiranthes lacera, a genus he had discussed at our Master Naturalist meeting in June.

Identifying orchid species can be intimidating but ladies'-tresses are distinctive.   The genus Spiranthes comes from the Greek speira, meaning "coil". Their inflorescence (cluster of flowers) is arranged in a spiral down the stem.  I was able to identify it as S. lacera because of the distinctive green or yellowish-green spot on the center of the labellum (lower modified petal).*

Photo by Mark Bower

The details of the tiny petals were impossible for me to capture with my equipment so I called Mark Bower.  He came down the next morning and took these beautiful pictures which show the orchid's distinctive features.  You can easily see the "yellowish-green spot on the center of the labellum" that was hard to see at ground level with a magnifier.

S, lacera range- Wikipedia

Orchids, like bobcats and black bears, are what I think of as common yet uncommon Ozark species.  If you look at a range map, orchids occur over the Eastern US and Canada and yet we haven't seen them before and native plant enthusiasts will make field trips just looking for them.  Their brief period of flowering and diminutive size lead to their infrequent discovery.  Even on the mowed grass we had a hard time finding all of them.  However once you've seen one you are much more likely to recognize another.  On subsequent days Barb found them while eliminating some sericea lespedeza between  trees bordering a bottom land field and under a power line cut.

Photo by Mark Bower

*  Gobotany.newenglandwild.org has details.

What is it?
Below is a photograph I was sent by our friend Georgia, who found it on the edge of her dog's water bowl.  She asked me what it was and I was way off with my first guess.  Now you can try before we answer it in a posting next week.

Animal, vegetable or mineral?

Pawpaw Poacher

Asimina webworm

Click to enlarge

While I was checking out a pawpaw (Asimina triloba)  grove for fruit, I noticed that most of the trees had some of the leaves hanging down, pale to dry and shriveled.  The damage seem to occur along the petiole and they were usually stuck to an adjoining green leaf with silk.  This was my introduction to a pyralid moth, the asimina webworm moth, Omphalocera munroei.

Wrapped in silk, heading back into the frass

When I began to carefully unwrap these leaves I found occasional caterpillars, small and brightly colored.  They were deep inside the leaves which were bound together by silk and filled with frass (insect poop).  As soon as I exposed one, it quickly crawled further into its protective frass-filled pouch.  When I put one on the hood of the truck it thrashed violently and crawled to escape much faster than the average caterpillar.

Adult asimina moth -  Mark Dreiling

The tiny moth lays it eggs on the underside of older pawpaw leaves.  Although studies have shown that their caterpillars grow better on fresh young leaves, the older tougher leaves make a better protective shelter.  The earliest larvae pull leaves together with their silk to create a communal home while later instars will live singly in rolled leaf edges.  Both types of shelters have been shown to help protect them from predatory wasps which lay their eggs on caterpillars for parasitic development of their young.

Green and dead leaves form the shelter

A caterpillar will chew on the petiole, causing the leaf to die and dry out.  It will then tie it onto a fresh leaf with silk, the dry leaf providing protection while it chews on the green one.  Soon there may be four dead leaves forming its cave before it heads out to another branch.  Eventually the moth can even defoliate the tree late in the season as well as bore into the fruit.

Chewed leaves and new leaf growth

While this is not good for the individual pawpaw tree, it may benefit the zebra swallowtail whose caterpillars require pawpaw to grow to adulthood.  The zebra cats also grow best eating younger leaves.  After the asimina caterpillars kill leaves, the pawpaw responds by growing new fresh leaves that the zebra cats need.  Meanwhile, the asimina stick to their mature leaf diet for their shelter properties.  In Florida this has been shown to increase the number of second summer broods of zebra swallowtails.*

Our asimina babies

Editor's note
We are currently raising Asimina caterpillars out of curiosity, just to see the adult moths.  Who knows why, as there are more than enough of them this year at Bull Mills.

* See this reference

More of egg laying strategies 

Leaf age 

• Details on the zebra swallowtail-pawpaw connection are in this blog.
• Pawpaw is also host to the pawpaw sphinx moth, pink-spotted hawk moth, and tulip tree beauty moth. 
•  

Scelionidae Wasp Hatching

Mark Bower sent me these pictures last month, a good example of what you can find with curiosity.....and a good photographer.  These eggs are 1mm in diameter (1/25 of an inch), hard to see with a magnifier and impossible to photograph.  I asked him to describe his find.

"These eggs were deposited on a wooden post on our front porch. When the first one emerged, it stayed with the eggs constantly. When others hatched, the first one watched intently, and immediately either attacked or mated with them. I say two "hatchlings" get attacked and expelled from the egg cluster, one gets mated with, and several others die (why?) before they could get out (after opening their eggs). Not sure what all was going on there; it all seemed sort of odd."

We sent this to Chris Barnhart who explained that "these are parasitoid wasps, emerging from eggs of hemiptera. The wasp is likely in the Scelionidae family."  Hemiptera are the order of "true bugs", the order that contains aphids, planthoppers, leafhoppers, shield bugs, and stink bugs that often plague your garden.  In this closeup Youtube video by Mark, at 1:03 you can see a wasp emerging from a hemipteran egg and an immediate attempted mating by a newly emerged male who was waiting for her to come out.

Not all species are black

The scelionidae family contains over 3000 species of parasitoid wasps.  They all lay their eggs on the eggs of insects or spiders where their young grow by using their host  as food.  Generally they are careful to eat only nonessential parts at first, prolonging the life of the host to obtain maximal nutrition.

These wasps and the eggs they attack are tiny!

Antennae with 9 visible segments

A typical scelionid wasp is black and slender although some are various colors and shapes.  In general they have long elbowed antennae with 9 or 10 segments.  These are tiny creatures, ant sized, and could be mistaken for them without magnification.  Most are winged except for some species that parasitize wingless beetles.

A miniscule wasp measuring 3mm in length would have a difficult time fly all over looking for insect eggs to parasitize but they have developed a strategy to find a host for their young- hitchhiking.  They get on the back of a female insect and hang on until she starts laying her eggs.  Then the wasp gets off and starts laying her eggs inside her hosts fresh laid eggs.  Finally, she adds a strong odor, warning away any other parasitic wasp that these are taken.*

Winged scelionid wasp

We tend to be judgmental about plants and animals, classifying them as "good" or  "bad" by our personal criteria.  In ecological terms, many "bad" bugs and plants are just misplaced, located where it is inconvenient or problematic for us.   Eating our garden or the caterpillars of butterflies we treasure labels them "bad".   Meanwhile they are, to paraphrase Arthur Dent in Hitchhikers Guide to the Galaxy, "just these bugs, you know", making babies the best they can.  And if you look closely, they can even be a little cute.

Cute? -  Compound eyes, "The better to see many of you with."

 *  More details at this beesnwasps.com page.