Friday, September 30, 2022

Owl Pellets


I recently was gifted owl pellets by Ben Caruthers. The dried undigested regurgitated remnants of an owl meal is an exciting exploration for a 5th grade WOLF student. I stored them in paper egg cartons inside a ziplock bag in the dining room. I have a very tolerant wife.

Exuviae of emerged moths - notice the wing features below

When I opened them a month later I could see exuviae, empty pupa cases with remnants where there had been wings developing. Among the collection of digested rodent bones, some of the debris was moving. After filming it, (a historic term for video), I extracted a wiggling piece of debris and captured a case-bearing larva attempting to escape as seen in this video.

The larva lives this stage of its life in a tunnel it glues together from debris.  The owl pellets in the egg carton had a least a hundred of these little guys.  Now the question was what were they?  
6 mm moth in owl pellets

A week later I had an answer.  I found several of these 6 mm long moths in the bag.  a quick Google search of "case-bearing moths" returned lots of links pointing to clothes/carpet moths in the Tineidae family.  The majority of these feed on fungi, lichens, and detritus, which fits with the material in these pellet remnants.

This is most likely the case bearing clothing moth, Tinea pellionella.  They are distributed world wide and are frequently associated with human populations.  There are a few other similar species in the family that can only be identified by examining their genitalia so we won't go into that.   

"T. pellionella larva eats mainly fibrous keratin, such as hairs and feathers. It can become a pest when it feeds on carpets, furs, upholstery, and woolen fabrics. It also consumes detritus, cobwebs, and bird nests."  -Wikipedia

The larva lives inside a snug case it constructs from debris such as fibers and hairs.  It extends its body to crawl around, hauling its home for protection.  Incredibly, it can turn around in the case to protrude its head and legs at either end and drag the case in either direction.  Finally they will form a pupa and eventually crawl out and expand their wings.

So back to the other question, what are owl pellets and why would a grown man collect them?  Owls often swallow mice, voles, small birds, and other prey whole.  After its gizzard has sorted out the indigestible parts such as fur, feathers, teeth and bones, the owl regurgitates them in a oval owl pellet.  This frequently occurs in a roost where they collect on the ground underneath.  Taking these to the 5th grade WOLF School, we students young and old, will examine them to try to determine what the owl had been eating. 


There are lots of resources available to students of all ages.  This brings out your inner 5th grader without having to get on a bus every morning.

Tuesday, September 27, 2022

Summer Egg Hunt #

Tonya Smith sent me on a non-Easter egg hunt with these picture of a string of barrel shaped eggs laid on a mulberry sapling leaf.  A search for insect egg photographs brought out a likely suspect, a leaf-footed bug, Leptoglossus oppositusA deeper dive found a picture of the critter in action below. 

The name leaf-footed bug comes from the shape of the tibia of many of the Coreidae family.  There are 88 species known in North America.   L. oppositus is extremely common across the eastern US and I find lots of them in the fields every year along Bull Creek.  

 L. oppositus is distinguished by the deeper scallops in the leaf-like feature of the hind tibia and the addition of three white spots across the hemelytra, the name of forewings in true bugs.

Proving the identification of the eggs down to species is hard but I would argue that the circumstantial evidence is strong.  Red mulberry is one of the host plants of the species as listed in BioOne.

Eggs closeup - Tonya Smith
Laying eggs - William Dedo



The eggs that Tonya photographed with their barrel shape and bulls-eye circle are fairly distinctive as seen at several sources.   Now enough of this hunt, it is time to go back to work.  No, not really - this isn't really work.

Friday, September 23, 2022

Rusty Spider Wasp

Building her nest - BC

Ben Caruthers comes through again with a great set of pictures.  He shot this red wasp and identified it as a rusty spider wasp (RSP), a lot easier to pronounce than its scientific name Tachypompilus ferrugineusThis is a large and impressive wasp that dives into its work head first.


Rusty spider wasp dragging a wolf spider across the ground
Click to enlarge - MDC

Spider wasps belong to the family Pompilidae.  These wasps visit flowers for nectar but their fame comes from killing spiders to feed the family.  The female stings her spider prey into paralysis and then drags the spider backwards to her nest, gripping the incapacitated spider with her mandibles.  The trip can be long and laborious as the spider is frequently much larger than the wasp.  Maybe that is why they call it going into labor?

Spider Wasp and Wolf Spider - Tachypompilus ferrugineus
With a wolf spider prey - Ted Kropiewnicki CC

Once the nest is prepared to her satisfaction, she grabs the spider and rolls it over so it is on top of her while she deposits a single egg before covering it with soil.  I frequently wonder how we know details like these but in this case it was observations by R.W. Strandtman described in this more detailed source.

The RSP specializes in collecting wolf spiders (Lycosidae).  Other species of spider wasps also tend to specialize in their spider prey, some with free living hunting species and others using web spiders.  The young wasp will get all its nutrition from this spider while all adults feed on nectar.

After this considerable effort to deliver and feed a single young, I wonder if she doesn't tell the next male that finds her, "Not tonight, I have a headache!"

Saturday, September 10, 2022

Giant Walkingstick

I found this stick insect in the bed of my truck after emptying a load of cut branches.  This is a giant walkingstick,  Megaphasma denticrus, quite distinctive in coloration.  This is the longest insect in North America, reaching up to seven inches long.

It had a rough day and was missing one leg but that didn't keep it from climbing onto my hand and start heading upward, the only direction most stick insects want to go.  During the day they cling to the tree, sometimes swaying a little like a small branch.  Their defense is to drop to the ground and they are light enough to survive the fall.  Then they immediately start to climb up for food and shelter.  M. dentricrus adult's favorite food is oak and grapevine leaves.

This specimen is a male, defined by a large, single spine on the underside of its mid and hind femora, the first leg segment like our femur.  Another distinctive male feature is the clasper at the end of its body.

Copulation - Marvin Smith CC

Males tend to be smaller and far fewer than females.  The copulation consists of the male using his clasper to hang on to the female's genitalia, fertilizing the eggs as they come out and immediately drop to down to the forest floor.  The male may hang on for several days, eating during this time. 

The female may produce 150 eggs with three eggs per hour.  Her ovipositor has a small flipper which propels them randomly, ensuring that they are scattered and less likely to compete for vegetation.  (See ADW)


Clasping copulation - Marvin Smith cc

The young offspring feed on grass and leaves, particularly oaks and grapevine.  They will go through four to five molts before achieving sexual maturity.  This species is known to regenerate a missing limb but in this case I wasn't able to raise it long enough to make it to the WOLF School alive.  I think it died of a lonely heart, never having reached its biological imperative.

Ben Caruthers sent this incredible macro of its eye.  Now check this Bugguide link for more photographs.