Red-backed Jumping Spider

The picture on Friday's blog is a facial view of a spider showing two big eyes like headlights, two smaller eyes to the side (turn indicators?) and four small eyes across the top.  Taken with my pocket Lumix, the picture lacks the clarity of the big league photographers but I suspect some of you recognized it as a spider.  The blue-green structures are the chelicerae, hollow mouth parts which connect the venom glands to the fangs at the tips.

Kevin Firth emailed within 4 hours with an ID as a jumping spider of the genus Phidippus.  I was amazed because spiders are tough except some of the more distinctive species.  I have contacted a lot of entomologists over the last few years, and even they sometimes ask if I know a "good spider expert."

Some species can be narrowed down by their web construction, habitat and body shape.  My specimen jumps dramatically, which is how I spotted it in Brian Edmond's dense prairie plantings. The final ID as red-backed jumping spider, Phidippus clarus, was made from browsing through jumping spiders in Bugguide, and comparing each with my full body photograph.

There is a lot of information on P. clarus on the web, particularly on Wikipedia.  Some of it is highly technical but there is also a lot of gee-whiz facts.

• Those big eyes really work.  Their vision exceeds that of a cat and is 10 times greater than the dragonfly which is the most acute of all the insects.
• Their powerful back two sets of legs allow them to jump 50 times their length, the equivalent of my jumping 250 feet.
• "In an experiment, P. clarus was offered as many fruit flies as it could eat, and in four-hour sessions individuals took 17 flies on average – while one took 41."
• Males compete for the largest females which then produce the largest number of offspring.  "When P. clarus males compete for females, the winners are those that produce the most vibrations on the surface and those that are largest. Contests between females involve less displaying, and physical fights between females are more likely to end in injury or death. " Mating rituals are complex and the average female produces 135 eggs in her sac.
• They hunt by sitting at the top of vegetation and pouncing down on their unsuspecting prey.  They, or their egg sacs, are placed sometimes in agricultural settings to feed on plant pests.

All spiders have silk glands which we associate with webs but some have adapted them to other uses.  The jumping spiders make silk shelters for protection of their eggs and a safer place to hang out while they are molting.

You can see a video of male and female P. clarus on this rkwalton.com link.  Arachnophobes beware.
An extensive collection of jumping spider videos can be found at this Dick Walton Natural History Services link.

Eight-spotted Forester Caterpillars

Roy Thompson sent us these pictures of caterpillars.  Here he shows what a walk in the woods by a sharp-eyed and curious naturalist with a modern phone camera can accomplish. 

He is one of several of our Butterfly House friends who can't pass a chewed leaf without pausing to see what's eating it.  In this case he was working when he saw a tree draped with grapevine and inspected the leaves.  He found several eight-spotted forester moth caterpillars, Alypia octomaculata,  of varying ages and used his I-phone to get their pictures.  After that he carefully collected the caterpillars and the grapevine leaves to raise them in a safer predator-free environment.

Early instar out for lunch

After emerging from their tiny eggs, these caterpillars likely chew up the remains of their former home before eating through the nearest leaf.  From this time on they will be non-stop eating machines.  Most lepidoptera (butterflies and moths) caterpillars require specific food plants to survive and grow.  In the case of these foresters, they need grapevine or Virginia creeper.  They eat everything tender enough to chew including small tendrils, leaving only the heaviest veins and leaf petioles.

They will be going through five ever larger caterpillar stages, called instars.  An early instar is seen to the right crawling up the petiole of a leaf.  They eat constantly, pausing only to avoid bad weather and to occasionally slip into something more comfortable.

More accurately, they slip out of something uncomfortable, skins now too tight to hold their expanding bodies.  This shedding or molting starts by attaching the rear of their abdomen to a structure, then unzipping the skin on the back of the head before crawling out of the old skin like we crawl out of a sleeping bag.  The new skin has room to expand, containing its host until it is ready to progress to the next instar stage.

Fourth instar- Click to enlarge

Like many other caterpillars, each instar looks a little different in color or pattern.  Some types of caterpillars change color and shape so dramatically that you would never even guess that they are the same species.  In this case the last instars look similar although larger.  Soon the last instar, seen at the top, will form a pupa, the last step before the final reincarnation-like act of emerging as a beautiful moth.

Life is hard if you are a juicy colorful caterpillar perched on a leaf.  Grape growers consider them a pest and may spray them.  These cats defend themselves from predators by vomiting a clear orange fluid.  They also will drop off the leaf and are spared a rough landing by a bungee-like cord of silk.  Roy's cats are living in a more protected environment so you and I will have to wait a while for the next installment in their story.

Missouri Oaks in Minnesota

Mighty Missouri oaks growing in Minnesota- Matt Kaproth

Missouri oaks are growing in a lab in Minnesota in a study of Relative Growth Rate and drought tolerance between species.  We described the collection process in last fall's blog so I won't repeat all the science behind it here, but will quote from that blog to explain the why of the study.

"We can look into which oak species withstand stresses better than others. With the recent droughts (and more predicted to come), we can identify which lineages have drought-tolerance, which can pass on this trait, and which species stand a better chance to survive with changing climates. You can’t get anything for free in nature though, and it’s hypothesized that lineages that can handle water stress have slower growth rates. Identifying this trade-off will let researchers predict species range limits and guide managers about how to care for their oaks."

The research is headed by our friend Dr Matt Kaproth.  Matt is a PhD in botany.  In the description by the child of a friend with a PhD, "Dad is a doctor, but not the kind that helps people."  He sent me some pictures of his research as well as more information on the process.

Forest under development- Matt Kaproth

In Matt's own words:

"I ended up planting over 5,000 acorns of 41 species. They've been growing on the Saint Paul campus of UMN for 5 months and I have currently transplanted 1000 plants.  I'm setting up irrigation supplies to start changing the watering treatments for the big plants soon - watering to saturation every other day, every other week and monthly. We'll see which species can handle drought and which fizzle out. We think there is a tradeoff between Relative Growth Rate (RGR) and drought tolerance, meaning that a plant that can handle drought has a lower RGR, thus there's a cost to being able to withstand drought - you put on less weight than ones that can not (but you stay alive)."

While the methodology of measuring the RGR is complex, the concept is understandable to us simple naturalists.  The RGR quantifies the speed of plant growth.  It is the mass increase per above ground biomass per day.  Over time as the plant grows, the RGR usually decreases as the plant biomass increases.  This is probably because as the biomass (roots and stems) increase, the top leaves start to shade the lower leaves, limiting photosynthesis while the plant's respiration (yes they "breathe") continues at a rate proportional to the biomass.  Also, with time, the soil nutrients can start to be depleted.

Matt's study may eventually contribute to our knowledge of which trees are best to survive our changing climate and still grow larger to help suck the increasing CO2 from our atmosphere.   Maybe he is the kind of doctor that helps people after all.

Coming soon to the blog.  
What is it?

Wavy-lined Emerald

Camouflaged looper with flower petals attached-  Charley Eiseman

Kevin Firth got me started looking at the wavy-lined emerald moth with this note. 

"The larvae are flower feeders that camouflage themselves with bits of whatever plant they are feeding on.  We had a bunch of them about five years ago around the house.  I found them on Prairie Blazing Star."

The wavy-lined emerald,  Synchlora aerata, is a fascinating critter.  Its caterpillar is commonly referred to as a camouflaged looper.  Unlike the camo of natural coloration, this caterpillar will attach plant fragments, especially flower petals to its back as it feeds, nature's version of a ghillie suit.  It is the only wide spread species that applies this artistic camouflage.

Synchlora cat- Steve Kortum

Sticky cat - Synchlora aerata Marvin Smith

The results can be quite striking and variable like those above, to the degree that you would never guess that these were the same species.  Part of the reason for the colorful variation is that they feed on a wide variety of plants including many flower heads and petals as well as trees and shrubs.  They seem to prefer composite flowers, especially (Asteraceae), including Aster, Rudbeckia, Liatris, Solidago, and Artemisia.  This gives them a wide variety of colors to chose from.  Since the fragments are always fresh looking they are probably replaced daily.

Dressed up for dinner- Kevin Firth

Find the looper caterpillar- Marie L. Schmidt

 Wavy-lined emerald - Synchlora aerata Tom Murray

The adult moth is a pale green with faint wavy lines running along the wings and a dainty fringe on the hind edges.  They are found widely over North America.

More caterpillars are seen on this Bugguide link. 

Click on this video showing attached flower petals shaking.

Abandoned Turkeys Get New “Mom”

From Jennifer Ailor
 
John Holt, who lives south of Allan Keller and me on Highway W southeast of Ozark, discovered a nest of turkey eggs hidden in the tall grass he was brush hogging in early July.  They were fresh so he carefully transferred the seven eggs to his brooder house where in short order they hatched.

Now about a week old, the babies are already are losing their fuzz. As he begins to let them out during the day, John expects to see them flying at two weeks and soon roosting in trees. Before you know it, he says, the young ones will attract mature turkeys and return to the wild with those birds. Based on others’ experiences, he doesn’t anticipate imprinting problems.

Most baby turkeys don’t make it to adulthood or even close. As poults, in their first three weeks of life, they are tasty eating for just about every predator, plus are sensitive to cold and wet. The mother hen is their only protection. Without that mother, these young turkeys are fortunate indeed to have been given a chance at life.

Editor's note:
What to do with abandoned baby animals is always a tough call. We know that if a baby bird is found away from the nest it is best to leave it for the mother bird to deal with. What about turkeys? If you find a turkey nest it should be left alone, giving the mother a chance to continue to brood the chicks. However, in this case the nest was close to a house, the tall grass cover had been mowed down, exposing the nest, and there are dogs, coyote, fox and bobcats around. I believe this Illinois Extension article confirms John's wisdom.

"Wild turkeys lay an average of 10 to 12 eggs, approximately one egg a day until the hen has a full clutch. Incubation is done by the hen only and lasts for about 28 days. Hens are very sensitive to disturbance while nesting, and are likely to abandon their eggs if they are startled from the nest. Young turkeys are called poults and are cared for by the female only. Poults are ready to leave the nest within 24 hours of hatching." 

Poults eat primarily insects during their early growth phase when they need lots of protein. They are particularly vulnerable in the first 10 days before they can fly to roost in the trees. Until then, John has his hands full.

One-eyed Abbott

I stumbled across this picture in my files yesterday, an unknown from 2010 that I had never identified.  Its dramatic single eyespot on the top of the head was distinctive but I couldn't find a match so I sent it off to Kevin Firth's same-day service.  Bingo!... Abbott's sphinx moth caterpillar.

The caterpillar of Abbott's sphinx, Sphecodina abbottii, changes its appearance dramatically  during its four instars (molts).  As you can see from the pictures below by Jo Ann Poe-McGavin, the first instar starts with a horn resembling a hypodermic needle.  The second instar loses the horn, converting it to an orange spot.

First instar- note horn

Later instar- horn replaced with orange knob

With the final instar before it forms its cocoon, things get really interesting.  The orange spot becomes a very convincing eyespot, complete with iris, pupil, and even the white reflecting spot in the middle.  To complicate things further, it can either be a brown color with 10 pairs of pale green saddles or come out in a tan wood-grain pattern like ours above.  If poked, it is said to squeak and bite at the attacker.

My wood grain version

Last instar, green version- Eddie Calloway

Abbott's sphinx moth- CircusCyaneus

The moth that emerges from the cocoon is no slouch either.  Its scalloped wings and coloration blend right in with tree bark and it adds to the effect by raising its abdomen at rest, resembling a broken twig.


Thanks to Jo Ann Poe-McGavin who makes all her pictures available for our common use.  She has submitted more than 3,000 pictures to Bugguide. 

June Beetle Grub

Barb spotted a big fat grub in our lawn at home and laid it on the patio table and said, "You have got to see this!"  As I watched, it twisted around from its C-shaped posture, rolled on its back and started crawling with its legs in the air.  I spent the next few minutes turning it over to get it to repeat the performance, a feat that it never tired of.  Check out it doing a backstroke on this video.

With the help of Google, I discovered that only the green June beetle, Cotinis nitida, and the bumble flower beetles, Euphoria, travel this way, and the June beetles are far more common.  Their legs are short and considered inadequate for travel but they wiggle them in the air as they go, as though that would help.  They have short stiff hairs on ridges of their backs which help them gain traction on the grass.

The third and final instar overwinters eight inches below the surface.  In the spring it burrows up closer to the surface, then moves through the soil on its back, feasting on decaying matter before forming a pupa.  It uses sticky secretions to hold soil particles together, forming a protective case from which the adult beetle will emerge in 16-18 days.

Green June Beetle- Wikimedia

The adults meet on your lawn, mate, then the female lays her eggs three inches deep in rich organic soil.  They might have to hunt for a home in nature, but they thrive where humans provide nurseries such as fertile lawns and gardens.  The eggs are buried in clusters of 10-30, wrapped up in a clump of dirt.

The grubs that emerge feed on decaying matter.  They are considered a serious pest on tobacco plants as they crawl through the soil, loosening and uprooting the plants.  They should be the symbol of the American Cancer Society campaign against smoking, but instead they are considered pests because of the damage they can do to lawns.

The large blue-winged wasp, Scolia dubia, is commonly seen flying low over grub infested lawns.  The female wasp actually digs into the soil to find green June beetle and Japanese beetle larvae.  She then stings a larva into paralysis and lays her eggs.  When they hatch, her larvae will consume the grub.  Even Japanese beetles have some benefit. 

To identify white grubs, go to this guide.