Nature Blog Network

Wednesday, August 20, 2014

Road Hog

Answer to "What is it?"

Driving down our lane, I encountered an obstruction.  A three foot timber rattlesnake was basking in the 85 degree heat and showed no inclination to move.  When I got out of the truck and approached, it assumed a defensive position rather than escaping into the thickets on either side of the road.

Defensive coil - Click to enlarge
If you click on the picture above, you will notice that its head is tucked, even hidden directly below the rattling tail.  The rattle serves as a warning to those of us who know (or should know) better than to pick up a snake.  It is likely that this developed as a way to lure a curious animal such as a rat that is then dinner, a technique called caudal luring.  Having its head right by the rattling tail allows it to strike the target quickly as well as expose its least vulnerable part while protecting its head.  Another example of caudal luring is the bright yellow tail of a young copperhead, although one study suggested that tail color didn't affect the success in pygmy rattlesnakes. 

Young copperhead - note yellow tail lure
The problem now was it was hogging the road between the two wheel paths.  I was afraid if I tried to straddle it with the truck it would try to escape and be run over.  It had now settled down, still coiled but with its tail upright and motionless.  I tried pushing it to the side with a long stick (let me emphasize long) and merely succeeded in annoying it as seen in this video.

I finally used a long watering tool as a modified snake hook and lifted it to the side and it slithered off in annoyance.  This rattler was smaller than the ones we occasionally see in the same area of the road so I suspect that they have been breeding successfully on the glade.  As long as they stay there and not at the garage and house, we will peacefully coexist.

Monday, August 18, 2014

Butterfly Aggression

Monarch interrupting tiger swallowtails mating - CB
What could be more peaceful and serene than butterflies fluttering around in the Butterfly House at Close Park?  Like a reality show named Real Butterflies of Springfield, there is a lot more going on if you watch closely.

Chris Barnhart has videos of lepidoptera lust and mayhem posted on Youtube.  The first one pictured above was a monarch persistently interrupting a pair of mating tiger swallowtails.  The monarch continued in the interspecies "menage a trois" until Chris physically removed it, as seen in this video.  You try explaining what the butterflies were doing to a group of little kids!

Male monarchs wrestling on the gravel floor- CB
I don't think of butterflies as aggressive but they can be very territorial as well as competitive in breeding.  Red admiral butterflies are notorious for defending their nectaring territory.  Chris tells me that monarchs are also aggressive, an important trait if you have to fly 2,500 miles to find a branch to land on in a crowded forest.  The two male monarchs pictured above can be seen in this video doing their impression of W.W.F. contestants.  The cause of their altercation is unknown.

It is an insect eats insect world in nature and this continues in the house.  Although we try to control loss at all monarch stages, there are lots of predators in every stage in their growth.  When the caterpillar hatches it eats its egg before starting on the milkweed host.  At times the caterpillar will come across another egg and eat it.  This fratricide increases the survival odds by ensuring a better food supply. 
Rat nibbling on a black swallowtail caterpillar - CB
There has been an unusual predator in the house recently.  This rodent above, possibly a cotton rat, was seen munching on a black swallowtail caterpillar.  While this is part of the balance of nature, it is considered rude in the Butterfly House.  It is facing deportation soon and will be available to the first caller.

Coming next, but what are they?

Friday, August 15, 2014

Algae Bloom on Steroids

David Casaletto wrote an interesting issue of Ozark Waters newsletter
discussing the Toledo water crisis and its Ozarks implications.  The pictures are striking.  I had read about the devastating algae bloom on Lake Erie that caused a shutdown of all potable water in Toledo, Ohio for two days.  We are used to the occasional boil order in small towns, but this was 400,000 people!  And no boiling solutions as boiling would only concentrate the toxin.

Lake Erie from satellite - NASA

Lake Erie water sample
What was striking in the article was the photographs. You couldn't make this worse with Photoshop. The ecological impact came from a combination of farm fertilizer runoff, septic systems around the heavily developed lake shore and global warming.

This blue-green algae problem isn't just limited to Lake Erie.  It has been reported to cause sickness in many Wisconsin communities.  The algae is common and can occur in our Ozark waters, but so far not in toxic concentrations.  As we have more warm weather and pack people closer together, the algae risks climb.  We have no control of the weather, but we can limit runoff of fertilizers and animal waste into our streams. 

Wednesday, August 13, 2014

Glue traps

Rat snake on a glue trap.
Wood rats and mice are all part of country living and so are glue traps and rat snakes.  Unfortunately occasionally a glue trap and a snake become intimately acquainted.  If the snake is found within a few days, it can usually be released without harm.

Our first experience was with a five foot rat snake curled tightly on two glue traps.  Freeing it required 15 minutes of careful peeling (tail first) while inserting little pieces of newspaper to keep it from sticking again.  Once it was free, the belly was very sticky so we powdered it with flour.  It was probably certain it was headed to the frying pan.  It didn't learn anything from this as 2 weeks later it had climbed back into the second story crawl space of our house.

Red-bellied snake- note thin collar ring
We now know a better method of freeing a snake.  This weekend we had two snakes on our glue traps.  The first was a red-bellied snake, a small snake with an impressive name, Storeria occipitomaculata occipitomaculata.   We discussed this snake and its hot lips in a previous blog.  There was a thin ring around this specimen's neck, made up of three unconnected segments, unlike the thicker collar of a ring-neck snake.

Note the stretched skin of the neck
Three days later Barb found a black rat snake stuck to another glue trap.  It has been renamed a Texas rat snake (don't get me started on renaming) and we commonly find their skin sheds around the upstairs or in the well house of the creek house.  Their intact skin is very stretchy as you can see in the picture above.  When I picked up the trap he gaped his mouth impressively, closing it just before I got the camera focused.

The method for releasing an animal from a glue trap is quite simple.  Lay the trap on a flat surface out of doors and pour vegetable oil on the trap.  It slowly dissolves the glue as seen in this video, and the snake pulls itself off.  Ours got free before I could get the camera on it again and took off, probably expecting the flour to come next before a hot skillet.

Monday, August 11, 2014

Bobcat Babies

Bobcat family- Linda Bower
One of my favorite technologies is the game camera.  As the field has advanced, the capacity to take videos opens up new opportunities to the naturalist.  Linda Bower MN (Master Naturalist), has a Youtube channel full of observations from her land east of Springfield.  Her pond and trails are a virtual zoo of activity, as seen in this bobcat video.

Turkey family - Linda Bower
We see lots of turkeys and their poults this time of year, the young-ens now the size of Cornish hens.  While we find them scrambling to escape, Linda's game camera has filmed a video of this charming family scene.

Raccoon at play before eating tomatoes - REK
As we survey the half eaten tomatoes in our fenced raised garden, I have to remind myself that raccoons can be as cute as they are destructive.  They consider the five foot mesh fence a handy ladder, built for their convenience and the live trap for packrats a toy.  They turn them on the side before teasing out the veggie bait.  Linda's raccoon video shows their cute side.

You can see more at Linda's Youtube Channel.

Saturday, August 9, 2014

Aphid Cornicles

When Mark Bower sent the first pictures of the oleander aphids shown in the previous blog, the picture above stood out with its little brown spheres on the "tail pipes" on one aphid.  Mark researched this for me and came up with the description of aphid "cornicles".

Nymph with dry cornicles
Cornicles are structures unique to aphids.  They are little tubes extending from the last dorsal abdominal segment like exhaust pipes on the cab of a semi.  They are normally empty and short, easily overlooked on the nymphs.  In this voiceless creature, they are a way of shouting out a warning of danger.

When muscles at the base of the tubes contract, these hollow tubes secrete droplets of fluid.  Originally this was thought to be honeydew, but we now know that the honeydew beloved of ants is actually a digestive byproduct released from the digestive tract.

Aphid cornicles in action - Wikimedia
The cornicles secrete a mixture of hemolymph, lipids and an alarm pheromone called E-β-farnesene (for you chemistry geeks).  It can be detected by other aphids on this plant and in the surrounding area, sending the message "I am dying, run away."

As described by Ira Flatow at Science Friday,
"An aphid only produces E-β-farnesene after it’s been attacked. Once the alarm pheromone is released, any aphid within detection distance will stop feeding and walk or fall off the leaf it’s on. In species with long cornicles, the aphids will flex their abdomens and smear the pheromone onto the predator in the moments before death. This action ensures that wherever the predator goes on the plant, the other aphids know before it even arrives!  It’s totally sneaky. This behavior allows the other aphids in the cluster more time to escape predation."
The adult aphid is far less likely to release the hormone than the nymphs.  The adult has methods of escaping and may not be programed to waste as much energy producing the fluid.  Nymphs on the other hand are lined up in a virtual smorgasbord for predators, and the ability to escape in mass helps perpetuate the aphid species.

A lot more detail is at this link.

Thursday, August 7, 2014

Milkweed Aphid

 Mark Bower sent me the picture above, a critter on a milkweed.  It looked like an aphid and so with a brilliant piece of detective work I Googled "milkweed aphid" and came up with the identification.  

Like many organisms, when you dive deep enough, it has some interesting characteristics.  This aphid is an omnivorous plant sucker, feeding on sap of plants in the dogbane family such as milkweed, vinca and oleander.  It will even cross over for dessert on crassulaceae (succulents such as jade plant) and solanaceae (nightshade family).

All oleander aphids are female as males do not occur in the wild.  They are parthenogenetic (reproduce without male fertilization) and viviparous, giving birth to live nymphs instead of laying eggs.  The nymphs go through five stages all looking similar to the adult.  Some adults will develop wings when there is overcrowding or the plants are dying off, allowing the aphid to establish a new distant colony.
 Winged A. nerii - Ken Schneider
Reproducing in large numbers usually means an insect is a problem to some plants (and growers) but dinner for others.  This aphid sequesters toxic cardioglycosides from the plant sap of milkweed, making it distasteful to many species, just like the monarch butterfly.  In addition they make distasteful secretions on their cornicles (coming up next week).  When this secretion is applied to a spider's mouth parts, it will retreat and wipe its mouth (and presumably make a terrible face!)  This shows that the secretion is effective and that some entomologists have way too much time on their hands.

So what does eat these aphids?  Hover or flower flies, lacewings and lady beetles have no problem with their secretions.  A prominent source of predation are the aphid wasps such as Lysiphlebus testaceipes.   They lay their eggs on the aphid nymphs and the resulting larva enters the aphid which mummifies while the larva matures inside.

The oleander aphid can become a garden pest, injuring young shoots and producing a sticky honeydew which can develop a black sooty mold on it, not what you want on your garden flowers.  The aphids can be removed by hand and are vulnerable to insecticidal soaps and oil.  Gardeners should avoid other insecticides as they are also toxic to butterflies and other pollinators.
Large Milkweed Bug-  Mark Bower
Photo- Mark Bower
I was initially confused by pictures of another bug on the same plant, a deeper orange but co-existing with the aphids.  Kevin Firth cleared up the confusion by identifying it as a nymph of a Oncopeltus fasciatus, the Large Milkweed Bug. Seen below with the adult, it is a minor enemy of milkweed but a friend to science. It is easy to grow and to dissect, making it an ideal insect to study in the lab.

Large Milkweed Bug adult and nymphs-  Photo by Greg Hume
Like the aphids, they suck the juices of milkweed and accumulate toxic glycosides in their bodies.  This and their bright orange aposematic color serves to warn off many predators.
Details on the aphid are found at this University of Florida website.