Bioluminescence: Light Show Beneath the Sea

Bioluminescence: Light Show Beneath the Sea

If you like summer fireworks events, there is a great show ongoing during our warm summer months that you shouldn’t miss. Find an unlit dock along our coastal environs and take the time to pause, get down on your knees, and gaze into the starry… water. Our night skies are quite impressive in their own right, but our night waters will also put on an amazing show of glowing critters and flashing lights if you take the time to notice. Thousands of different marine organisms have the ability to produce light and the purposes served by this trait are many. Some animals use this tactic as camouflage and others to stand out for one reason or another. Being seen by others can assist with predation (luring), defense (startling or warning), or even reproduction (attracting a mate).

glowing jellyfish

Thousands of marine creatures create their own light, including many jelllyfish

Bioluminescence is the most accurate term for light emitted by living organisms; although sometimes you will hear it referred to as fluorescence or phosphorescence. Fluorescence however, is the term describing something that absorbs light energy from an external source and then almost immediately re-emits it. When the external source goes away, so does the fluorescence; i.e. it doesn’t keep going in the dark. Phosphorescence describes when something absorbs light energy from an external source and then slowly re-emits it over a longer timeframe, i.e. glowing stickers. In contrast to these other terms, bioluminescence results from a chemical reaction within the body of an organism. The trigger mechanisms can be quite varied in nature and some are even directly controlled by linkages with an animal’s brain and nervous system. Other times the light is triggered simply by a physical disturbance. This is the most common phenomenon observed by people as the water seems to sparkle from a boat’s wake at night or waves breaking in the surf. One of my earliest memories of this was as a teenager in the Keys while wading along the shore at night. Each splash would trigger a shower of sparks.

So, what is taking place to create this chemical reaction that gives off light? Well, scientists have learned a lot about it but still don’t have all of the answers regarding the incredible variety of ingredients and processes involved in the bioluminescent realm. In general, a molecule called luciferin is involved and when exposed to oxygen, it gives off light. An enzyme named luciferase acts as a catalyst to help speed up the reaction. There are apparently many types of luciferins utilized by different animals; and I’m guessing, many variations on the actual luciferases involved too.

During summertime the warm waters of the Gulf and our coastal estuaries are rich with planktonic life. If you look close at a dock post beneath the water you will see continual, tiny flashes being triggered as water moves around the stationary post. When you walk down the dock (very carefully, without a flashlight), you can also see streaks of light from startled fish swimming away. This light is emitted by single-celled dinoflagellates that are triggered by a disturbance near them. One fascinating account I’ve read, told the story of Jim Lovell (Apollo 13 astronaut), who used bioluminescence to find his way safely home. When the navigation equipment failed at night in the navy plane he was flying, he was able to turn off his cockpit lights and see the glowing wake from his carrier and follow it. I’m sure he was forever grateful to the tiny marine creatures that made this possible! If you can get to a coastal dock near you this summer, be sure to turn out the lights, and look down in the water for a spectacular, miniature fireworks show. No earplugs required.

Silent Night It Is Not!!! Cicadas Sing the Evening Away.

Silent Night It Is Not!!! Cicadas Sing the Evening Away.

cicada shell

Only a shell of its former self, the exoskeleton shed by a cicada is all that remains of the previous night’s long pursuits.

Autumn evenings in the panhandle are usually beginning to reflect the official change of seasons with cooler air and a slight lessening of the raucous din created by insects and birds. The recent early-fall hurricanes have brought the area a wide breath of hot, humid air, delaying the long anticipated start of relief from the sultry summer environment.

Anyone hearty enough to take an early evening walk in north Florida will experience a continuation of the frenetic activity and riotous sounds typical to summer in the south. The near deafening call of cicadas (Magicicada spp.) is part of the cacophony.

Once commonly identified as locust in the region, their near-mechanical buzzing originates from the protection of foliage in trees and bushes during the day or twilight hours. During the dark hours they sing often and relocate frequently.

It is important to note cicadas are not the locust of infamy which shred the green, lush landscapes and foretells famine. While locust and cicadas are both insects, the similarities end there.

These seldom seen or captured insects known for their boisterous, sometimes undulating, chorus do leave strategically placed souvenirs for the sharp-eyed observer. This discarded residue of their early life stages is a highly valued tool for many elementary school boys with a prank in mind. The hard shell is harmless, but under the right conditions does have a certain shock value appreciated by juvenile miscreants.

Their nymph stage skeletons are often seen on the trunks of trees, shrubs stalks and even the siding of buildings. The opaque brown shells are abandoned when the cicada outgrows it and then emerges to form a new exterior.

The process is similar in other insect species with an exoskeleton having very limited potential for growth and expansion. The rigid coating provides this creature an armored surface to fend off the challenges of being small and small in a big hungry world.

In some states, cicadas are famous for their periodic appearance in colossal numbers, sometimes as many as 1.5 million per acre. These once every 13 to 17 year swarms do not occur in Florida which has an insect friendly environment.

The 19 Florida cicada species fall into three groups based on overall size measured by the length of the forewings. They produce their songs with timbals, paired drum-like structures on the sides of the abdominal segments.

A muscle attached to the timbal plate causes the timbal ribs to pop inward and project outward when relaxed. Flexed rapidly, the cicada chorus can deliver hours of uninterrupted night music.

In Florida, only males have timbals and the females are mute. Most sounds made by males are calling songs which serve to attract the silent females.

Cicada nymphs live in underground burrows where they feed on xylem sap from roots of grasses or woody plants. Because xylem sap is low in nutrients, complete nymph development takes several years to successfully mature.

All cicada species molt four times underground. When the cicada nymph is ready for its fifth and final molt it makes its way to the soil’s surface. It climbs a short distance up a tree trunk or stem, anchors itself and molts for the last time becoming an adult.

If male, the new cicada will add its contribution to the nightly festivities. If female, she will quietly wait for that special, one in a million, nocturnal crooner.

To learn more about north Florida’s noisy night insects, contact the local UF/IFAS County Extension Office. Click here for contact information.

Backyard Shiitake Mushrooms: a Tasty and SAFE DIY Project

Backyard Shiitake Mushrooms: a Tasty and SAFE DIY Project

Have you ever eaten a wild mushroom and then wondered afterwards if you might have made a mistake? If you are prone to forage outdoors for tasty treats from nature, I’ll bet you have. The problem is, unless you are harvesting one of a few “foolproof” species of edible fungi, positive identification can be very challenging. Oft-times wild mushroom harvesters take a notion to branch out and seek new varieties that are outside of the identification capabilities of the novice mycologist. This is where folks begin treading on dangerous ground and may be at risk for gastrointestinal distress;

Properly inoculated shiitake logs can be quite productive

with symptoms that may range from a mild upset stomach to permanent damage or death.

Yes, death!

Everyone has heard about poisonous mushrooms but few people realize that some of the deadliest species are look-alikes for some of the tastiest species. And you would not be able to distinguish the difference by nibbling a sample. Even a small sample of some of the “bad actors” can be lethal, leading to painful symptoms and organ failure. If this scares you out taking a risk then this article has served a good purpose.

If you wish to enjoy a safe, tasty experience with a highly-prized mushroom species, just take up the hobby of growing your very own shiitake mushrooms. Shiitake comes from the root Japanese “shii” (meaning oak) and “take” (for mushroom). Shiitake mushrooms are a billion dollar industry in Asia with 92% of the world production coming from Japan. Many culinary and medical uses have been identified. This species was only available as dried mushrooms in the US until 1972 but with the removal of a ban on importing live fungi a commercial industry has blossomed.

Hardwood logs are the key, with oak being a preferred tree species. There are six considerations if you are to be successful:

1. You must acquire living Shiitake inoculum (the mycelial or rooting stage) already growing on a wood medium, usually hardwood dowels or sawdust (internet search will yield many providers).
2. Proper cutting and handling of the logs to be inoculated is important. Cut trees close to the time of inoculation (2 weeks max.), 4-8 inch diameter and 3-4 feet long.
3. Inoculate by drilling holes in the logs, inserting the living inoculum/spawn and seal the holes with melted wax to retain moisture. A single log may have 30-40 holes drilled in it.
4. Place logs in a shady/moist environment (i.e. under the canopy in a woodlot with at least 75% shade).
5. Maintain logs by wetting during dry spells. A sprinkler or mister run for a couple of hours a day works well.
6. Proper harvesting and storage is most important and information is available in many places online.

Shiitake fruiting is usually triggered by changes in temperature and humidity so spring and fall are key times to check your logs. It does not take long for a mushroom to go from the early “pinning” stage to mature, so weekly checks are advised. Significant tropical weather events will also stimulate fruiting. Logs produce mushrooms for at least two years, until the nutrients in the wood are used up.

Don’t be in a hurry though, as the full colonization of the log by the mushroom mycelium will take up to 9 months before mushrooms begin to appear. Remember, beware the risks of harvesting wild fungi. A small-scale shiitake growing operation is a safe alternative for getting your “mushroom-fix.” Also, be ready to compete with a squirrel or two for your crop as they know a good thing when they see it too.

Which Local Creatures Eat Venomous Snakes?

Which Local Creatures Eat Venomous Snakes?

In my job, I get many calls about snakes. Most people want to know how to tell a venomous from a nonvenomous one and how to keep them out of the yard.  I was recently reading a new book out by Dr. Sean Graham entitled American Snakes and in the chapter on snake defenses, he provided a long litany of local creatures who consumed snakes – some surprised me.  Check this out…

The “cottonmouth” gape of this venomous snakes is a warning. Notice the banded coloration of this individual.
Photo: UF IFAS Wildlife

First, most who do only consume smaller species of snakes – but the list is still surprising. Spiders… spiders were on the list.  He specifically called out the black widow – who probably could kill a small snake, but indicated there were others.  Scorpions, centipedes, fire ants, carpenter ants, giant water bugs, crayfish, and crabs made the list as well.  Some of these may consume snakes only after they are dead – but some can kill small ones.

 

From the vertebrate world he mentions the larger salamanders (such as the hellbender), and other snakes (such as the short-tailed snake and the coral snake). There are several mammals including shrews, moles, and even the rodents themselves are consumers of snakes!  He describes how hoofed mammals (such deer, goat, and horses) do not consume snakes, but can completely destroy one by raising and stopping on them – leaving only small segments remaining.  They have found the remains of snakes in the stomachs of all predatory mammals but the snake’s greatest threat are birds… by a long shot.  Species from passerines to raptors have been known to kill and consume snakes.

 

What about venomous snakes – who consumes rattlesnakes and cottonmouths?

There are surprises here as well…

 

Bullfrogs… bullfrogs basically consume what they can get into their mouths but this includes snakes – and venomous ones as well (though they would be small ones). From the fish world, both the gar and largemouth bass are known to consume venomous snakes.

A coyote moving on Pensacola Beach near dawn.
Photo provided by Shelley Johnson.

Opossums are known to consume at least 12 species of snakes, including venomous ones. They also consume ticks, fire ants, and have a very low occurrence of rabies – a cool animal to have around.

Other mammal consumers of venomous snakes include raccoons, otters, fox, bobcats, coyotes, and black bears. It is understood they must take smaller members of the venomous snake population – but a snake control is snake control.

 

Most wading birds in our marshes consume snakes, including venomous ones, but it is the red-tailed hawk and the great horned owl that are the masters. Red-tailed hawks are known to consume at least 35 species of snakes, including venomous ones, and – unlike other snake predators – are a larger part of their diet, they seek them out.  Great Horned Owls consume at least 13 species, and venomous ones are on the menu.

 

From the reptile world we begin with the alligator, who has little problem consuming large specimens of both the rattlesnake and the cottonmouth. However, many are snakes… yes, snakes eat snakes and some consume venomous ones.  Coral snakes, coachwhips, and cottonmouths have been known to consume other snakes.  However, it is the Eastern Indigo and the Kingsnakes who actively seek out venomous species.  It is known that kingsnakes have a protein in their blood that makes them immune to the viper’s venoms – and it appears the vipers know this and avoid them.  It is not known whether the indigo is immune, but it is known they will seek out venomous snakes and consume.  Both of these snakes can take relatively large venomous species.

 

Of these two, it is the Kingsnake who is the “king” – consuming at least 40 species of snakes. However, both the kingsnakes and the indigo are on the declined.  The eastern indigo is currently federally listed as endangered – there has not been a verified record of one in the Florida panhandle since 1997.  However, there are anecdotal reports and we encourage anyone who has seen one to send us a photograph.  There is an active indigo restoration program going on in Alabama and in the Apalachicola River area.  These are the largest native snakes in the U.S. (about 8 feet) and, along with the six-foot kingsnakes, are frequently killed.  There is evidence that as the eastern kingsnake populations decline copperhead populations increase, and Vis versa.  Some areas near Atlanta are currently experiencing a copperhead “boom”.  Clearly, we should reconsider killing both the indigo and kingsnakes.  We also understand that habitat loss is another cause of their decline, particularly in the case of the indigo.

 

When looking at this list of snake consumers we see species that cause other problems – alligators, raccoons, coyotes, and bears have all have had their negative issues. But many we just do not like, such as the opossum, really cause us no harm and control snake populations.  Everything has its place in the local environment and not one species seeks out humans for the purpose of harming us – this would include snakes.  The negative encounters are for other reasons.  But for those who have a deep fear, or are currently experiencing high snake numbers, seeing one of the animals on this in the neighborhood could be a relief.

 

References

 

Graham, S. 2018. American Snakes. John Hopkins University Press. Baltimore MD. Pp 293.

O’Connor, M. 2018. Personal communication.

“Ice Age” Tree in Peril: Florida Torreya

“Ice Age” Tree in Peril: Florida Torreya

Having just completed the Okaloosa/Walton Uplands Master Naturalist course, I would like to share information from the project that was presented by Ann Foley.

 

The Florida Torreya. Photo provided by Shelia Dunning

The Florida Torreya is the most endangered tree in North America, and perhaps the world! Less than 1% of the historical population survives. Unless something is done soon, it may disappear entirely! You can see them on public lands in Florida at Apalachicola Bluffs and Ravines Preserve and beautiful Torreya State Park.

The Florida Torreya (Torreya taxifolia) is one of the oldest known tree species on earth; 160 million years old. It was originally an Appalachian Mountains ranged tree. As a result of our last “Ice Age” melt, retreating Icebergs pushed ground from the Northern Hemisphere, bringing the Florida Torreya and many other northern plant species with them.

The Florida Torreya was “left behind” in its current native pocket refuge, a short 40 mile stretch along the banks of the Apalachicola River. There were estimates of 600,000 to 1,000,000 of these trees in the 1800’s. Torreya State Park, named for this special tree, is currently home to about 600 of them. Barely thriving, this tree prefers a shady habitat with dark, moist, sandy loam of limestone origin which the park has to offer.

 

Hardy Bryan Croom, Botanist, discovered the tree in 1833, along the bluffs and ravines of Jackson, Liberty and Gadsen Counties, Florida and Decatur County in Georgia. He named it Florida Torreya (TOR-ee-uh), in honor of Dr. John Torrey, a renowned 18th century scientist.


Torreya trees are evergreen conifers, conically shaped, have whorled branches and stiff, sharp pointed, dark green needle-like leaves. Scientists noted the Torreya’s decline as far back as the 1950’s! Mature tree heights were once noted at 60 feet, but today’s trees are immature specimens of 3-6 feet, thought to be ‘root/stump sprouts.’

Known locally as “Stinking Cedar,” due to its strong smell when the leaves and cones are crushed, it was used for fence posts, cabinets, roof shingles, Christmas trees and riverboat fuel.  Over-harvesting in the past and natural processes are taking a tremendous toll. Fungi are attacking weakened trees, causing the critically endangered species to die-off. Other declining factors include: drought, habitat loss, deer and loss of reproductive capability.

With federal and state protection, the Florida Torreya was listed as an endangered species in 1983. There is great concern for this ancient tree in scientific community and with citizen organizations. Efforts are underway to help bring this tree back from the edge of extinction!

Efforts include CRISPR gene editing technology research being done by the University of Florida Dept. of Forest Resources and Conservation- making the tree more resistant to disease. Torreya Guardians “rewilding and “assisted migration”.  Reintroducing the tree to it’s former native range in the north near the Biltmore Estate in Asheville, NC, which has maintained a grove of Torreya trees and offspring since 1939 and supplying seeds for propagation from their healthy forest.  Long before saving the earth became a global concern, Dr. Seuss (Theodor Seuss Geisel), spoke through his character the Lorax warning against urban progress and the danger it posed to the earth’s natural beauty. All of these groups, and many others, hope their efforts will collectively help bring this tree back from the brink!

 

The Armored Wanderer – the armadillo

The Armored Wanderer – the armadillo

The common nine banded armadillo scurrying across the lawn.
Photo: Les Harrison

The first light of morning can reveal random pockmarks in what had been the perfect lawn the previous evening. The culprit is not likely the neighborhood teenager with a reputation for inappropriate practical jokes.

The offender usually is the nine-banded armadillo, sometimes referred to as a Florida-speed-bump or Possum-on-the-half-shell. In addition to manicured landscapes, they also encroach in natural areas and destroy sensitive habitats.

 

Armadillos eat adult insects and larvae, but also quail and turtle eggs. They incessantly dig holes in their search for food, many times uprooting plants in their food search. Their foraging holes are approximately one to three inches deep and three to five inches wide.

Using insecticides in landscapes to decrease the armadillo food supply is not guaranteed, but may help reduce the digging. In cases where there is a large, and always ravenous, armadillo population this reduction of food may increase digging activity as they search more diligently for a smaller food supply.

Another consideration is all chemical treatments have to be reapplied on a permanent basis for long term control. Always read and follow label instructions for safe use of insecticides.

 

Armadillos rest in a deep burrow during the day and are usually active after dark. Burrows openings are approximately seven to eight inches in diameter, about the size of a one-gallon plastic jug, and up to 15 feet in length.

This exotic invasive may burrow under driveways, foundations and patios potentially causing structural damage. Additionally, their burrows in pastures pose a potential leg-injury hazard to large wildlife and livestock.

Several live-trapping techniques can be used to capture armadillos as they exit of their burrows. Because armadillos are nocturnal, trapping techniques designed to capture them as they emerge from their burrows should be applied late in the afternoon and checked several hours after darkness.

Fencing is another option to discourage the presence of armadillos. Relocating captured animals is illegal and not recommended because it only transfers the problem elsewhere and can spread this problem species.

Fossil records indicate the armadillo’s ancestors were as large as modern-day rhinos. One can only imagine what front yards would look like if they still existed.