It certainly appears that I am on an insect kick of late based on the content of my last three newsletter articles. Honestly though, when I think about it, bugs definitely rank near the top of my list for mystery and intrigue in the natural world. When we begin to dig into the details of their life histories, the revelations are mind-boggling, to say the least. Take the process of metamorphosis for instance. Scientists have described this process in detail and even identified the many hormones that trigger the changes that take place. But when I look at a caterpillar, then a pupa, and finally an adult Luna moth, all of the scientific knowledge in the world could never quell the flood of pure awe that wells up inside. Okay, I get emotional just thinking about it so let’s move on.
Luna moth caterpillars go through four molts, producing five instars, all exhibiting distinctly different characteristics. The fifth instar can be almost three inches long and has more bristly hairs on its skin than earlier instars. It also undergoes a dramatic color change and begins to wander as it gets very close to pupation. I saw one crossing a road once and took a picture to ID later. I was shocked to learn that it was the same species as the bright green ones I had seen pictures of. Another incredible fact about luna moth caterpillars is that when exposed to long photoperiods they tend to complete their pupal phase within 2-3 weeks but short photoperiods (i.e. as winter approaches) result in pupae that enter a dormancy period that can last up to 9 months. I remember finding a silk cocoon when I lived in Indiana during graduate school and brought it inside one Fall. I left it somewhere in the apartment and totally forgot about it. The following Summer we came home one day to find a large, beautiful cecropia moth hanging on the curtains (at least 8 months from when I found it).
Over my years of living in North Florida, I have had the fortune to come across several native moths belonging to the family Saturniidae. These have included the cecropia moth, luna moth, polyphemus moth, promethea moth, royal walnut moth (a.k.a. regal moth), imperial moth, orange-tipped oakworm moth, rosy maple moth, pine devil moth and io moth (beware the stinging spines of the io moth caterpillar). Some of the most visually stunning species in this group belong to the sub-family Saturniinae and are referred to as giant silk moths. This group spins a silken cocoon in which it resides during the pupal phase. When the transformation is complete, it uses horny spurs on its thorax near the base of the forewings to cut its way out of the silk cocoon. Once free of the cocoon it will find a suitable resting place to pump fluid from its swollen body into the wings until they are fully unfolded and hardened for flight. Males typically hatch a few days ahead of females and locate potential mates by homing in on pheromones produced by females.
The adult phase of a luna moth’s life is usually only about 10 days, during which time its sole mission is to mate and produce offspring. Adult moths do not even feed but live off resources stored during the larval phase. A good place to get a look at one of these magnificent creatures would be your local Recreation park during the summer months when the lights are on at the ball fields. Many of our giant silk moths are strongly attracted to lights at night and it is not unusual to find one flying around the lights or resting on a nearby structure. If you ever cease to be blown away by thinking about what it takes to make a moth into a moth, I would suggest you spend a few minutes searching your computer for images of praying mantis species (specifically, the orchid mantis). So many amazing insects out there!
Most of us have had the displeasure of hurrying to our car, late for some appointment, climbing in, only to be assaulted by…sniff-sniff…the overpowering stench of doggy poo on a shoe. I can handle many of nature’s nasty smells pretty well but this one nearly gags me. Imagine if this stuff never went away and kept accumulating on the ground. For any of us that have even one big dog, this would be a problem. Heaven help the dog lovers out there with two or more large canines. Well, this article will be paying homage to the unsung heroes of the manure-removal squad, who could give Mike Rowe a run for his money any day. You guessed it, dung beetles.
Dung beetles are most assuredly not the only critters who make their living by what we would consider disgusting means. Carrion beetles, fly maggots, vultures and many other creatures would qualify for an episode of “Dirty Jobs in the Animal Kingdom.” However, the incredible beauty of many species of scarab beetles (the group to which dung beetles belong), resulted in high reverence in the ancient Egyptian culture. In more recent times, humans have realized the benefits provided by dung beetles and have intentionally introduced them in some places to manage dung accumulation in pasture systems. Their tunneling not only takes the dung below for a nutrient recycling function but also brings soil castings to the surface, which reduces soil compaction and improves aeration.
I have seen dung beetles many times, as they work in the yard to reduce my chances of “stepping in it.” Until recently, I have not paid close attention to the incredible beauty of our local species. I had a great opportunity the other day to observe several beetles as they reduced a pile of dog mess to smaller messes and pulled them into their tunnels for long-term storage. The showy, metallic colors of red and green made it apparent why some refer to these creatures as “rainbow” scarabs. They were happy to ignore my presence as I took pictures only inches away from their frenzied activity to salvage their prized doggy treats.
The dung serves as food for both young and adults during periods when they remain underground. Females lay a single egg on what is referred to as a “brood ball” of dung and there may be several of these pre-packaged meals with an egg in the tunnel system made by the beetles. I was able to get some good photos of a beetle as it worked above ground moving dung balls away from the mother lode. It appears to be a species known as Phanaeus igneus, which occurs in our area along with a similar species named Phanaeus vindex. In Florida, Phanaeus igneus tends to occur in sandy soils, while P. vindex prefers clay-type soils. The finely sculptured elytra (hard wing covers) of P. igneus also distinguish it from P. vindex. Eggs hatch into a grub that matures below ground before emerging as a mature adult to continue the cycle.
Females of this species are distinguished from males by the lack of a horn.
The dung beetle’s sense of smell is truly a wonder of nature. I have seen them flying in for a sniff test literally within minutes of deposition. Within the next day or two, the only evidence of your pooch’s crime will be small mounds of soil where the excavations took place. I was so taken with these little jewels of the manure pile that you might understand why I think you should be just as amazed. So, the next time you find a fresh pile in the yard, drop down to your knees for a closer look and be prepared to be amazed. If the manure-removal squad has not appeared on the scene yet, give them a few minutes. It won’t take very long. In the meantime, you can be thinking about how you will explain your behavior to your neighbors when they inquire.
This praying mantis species mimics a wasp to avoid predation. Photo credit: Erik Lovestrand
When it landed on my hand, the first reaction was to brush it off as quickly as possible. However, something seemed to be slightly odd about this particular “wasp” that made me take another look. First, it was not prone to fly away as I moved my hand up for a better look. It even seemed okay with the interaction as I moved it around for a photo opportunity. There was also something odd about the shape of its body that wasn’t exactly wasp-like. As I looked closer, I realized that its head was very mantis-like and when it began grooming its antennae, I could make out the telltale folded arms that give the praying mantis its name. The yellow and black stripes encircling its abdomen, along with its wing shape and positioning veritably shouted “WASP!” I had never heard of a praying mantis that expertly mimicked a wasp so I did a quick internet search and found that this was a wasp mantidfly (neither a wasp nor a mantis). Mantidflies are grouped by scientists into a separate order called Neuroptera, which includes lacewings, antlions, owlflies, and others. Here are a few other mantidflies that mimic other wasp species.
A simple definition of mimicry would be: similarities between different species of animals. It is different from camouflage, which refers to an animal resembling an inanimate object, but both are effective forms of deception that generally benefit an animal in some way. Another common insect that would fool most people is the soldier fly. It definitely looks like something that could sting but closer examination will reveal only one pair of wings (a fly trait) rather than two, as bees and wasps have.
Now, not to take you too far into the weeds on this subject, but we should also mention the different types of mimicry that scientists have identified in nature and note an example of each. Henry Walter Bates studied butterflies in the Amazon and described a type of mimicry where one species mimicked the look of another that had some particularly nasty defense to predation. The mimic was lacking the defense mechanism but benefited by predators avoiding it based on its basic appearance. This type of mimicry is now known as Batesian mimicry and a good example are the butterflies that mimic the monarch. Monarchs are toxic because of the milkweed they eat during their larval stage. After a predator eats a few it learns to avoid anything that looks similar, such as a viceroy or queen butterfly. Fritz Mueller was a German zoologist who described a form of mimicry, now called Muellerian mimicry, where multiple species mimic each other and they all have a similar defense mechanism. This spreads the benefit to all that look similar by reducing predation pressure on all. The third type of mimicry is known as self mimicry, where an animal has one body part that mimics another (i.e. large eye spots to frighten or disorient an attacker), or a body part that may mimic some innocuous thing to fool prey into coming closer. We have a great example of this locally in the alligator snapping turtle. The tip of their tongue has a lure that resembles a worm and is capable of wiggling to enhance its effectiveness in tempting a fish to its doom in the vice-like jaws of the turtle.
Nature never ceases to amaze with the diversity and complexity of adaptations that various animals exhibit to gain an edge on the competition. When it comes to mimicry in the natural world, first impressions are generally wrong. I mean, that’s the point, right?
Well, the answer to this question should be obvious, right? However, when we take a closer look at these interesting creatures, the first impression created by their frightful name will likely evaporate completely. First, scorpions are considered venomous, rather than poisonous (I know, a technicality). They have many predators that eat them with no ill effect so they are not poisonous. Anything that has the ability to deliver a toxin by means of injection is classified as venomous. Next, the name is a true misnomer because the group of animals referred to as blue-tailed scorpions are actually a type of lizard called a skink.
Hatchling broadhead skinks sport a brilliant blue tail but lose this color as they mature. Source: NSF-EID
Scincidae is just one of sixteen families of lizards worldwide but it contains some of the most beautiful species of reptiles. Florida is blessed (yes, blessed) with at least seven species of skinks, with one being divided into five sub-species. Three of the five sub-species of the mole skink have “protected” status under state or federal laws.
Several of our native skinks in the Panhandle are challenging to identify at first glance, particularly during their younger years. The five-lined, southeastern five-lined and broadhead skink are all striped and have blue tails as youngsters, hence the origin of the frightening title for this article. According to folklore, these animals have the ability to deliver a painful sting with their tail. Well, as a lifelong reptile enthusiast, I have had the experience of catching many young, blue-tailed skinks without any stings.
Now, back to the question of whether or not these blue-tailed skinks are poisonous. From everything that I have read, there is no scientific evidence that skinks are inherently toxic when eaten by other animals. It is theorized that they could potentially harbor Salmonella bacteria but I have never heard of a documented case of this either. Many people hold the belief that when a skink in eaten by a dog or cat, it causes the animal to hold its head cocked and wander off to one side when walking. Veterinarians refer to these symptoms as vestibular syndrome and often cannot diagnose a cause. Vestibular syndrome is related to the inner ear or the parts of the brain that control balance and a sense of orientation to gravity. Our family witnessed this once with a beagle that we had and it lasted for several weeks but gradually improved to the point of normalcy. We did not witness her eating a skink, although she could have. However, there are many other more likely causes for this behavior including, inner ear infections, cysts or tumors, head trauma, parasites, etc. I suspect that inner ear issues are a common cause.
The largest species of skink in the Southeastern U. S. is the broadhead (or broad-headed) skink, reaching lengths of nearly thirteen inches. When mature, these skinks lose the blue tail and most of their striping to become a tannish brown. Males are larger than females and have a reddish color on the head, which intensifies during the breeding season. If you want to identify this species as a juvenile, you will need to look at the scales on the underside of the tail to separate it from the two species of five-lined skinks that inhabit our area. The central row of scales will be significantly wider than the other rows on either side. Broadheads have powerful jaws and will bite if harassed. If you want to see two males engaged in epic combat, give a watch to this YouTube link: https://www.youtube.com/watch?v=Z8qbexnZWew . Their stamina is truly amazing and they definitely come out with some battle scars.
Many of our local creatures lead fascinating lives that are rarely observed by the casual nature-seeker. However, thanks to those seriously committed naturalists, who may seriously need to be committed, we get the opportunity to peek into the secret lives of newts for some wild revelations. By the way, I do consider myself a naturalist and on occasion will come close to the edge of “crazy” in my nature adventures. Nevertheless, I do not believe I would actually qualify as “committable” because I have never totally lost that innate capacity to be freakishly startled when a treefrog jumps on the back of my neck in the dark. If you ever get past the point of being startled by things like that when on a nighttime herp hunting venture, you should probably speak with a professional.
Several months ago, I once again decided to test my measure of “committability” on a late night visit to the sinkhole pond behind my house. I was hoping to see what kinds of local amphibians might be active because I could hear several different frog species sounding off. As I waded in with my headlamp for a light source, I soon discovered that frogs are pretty darn good at not getting caught at night (imagine that). I had a dip net but never got close enough without scaring the quarry under. However, when I made a few scoops across the bottom in the shallows I was excited to see something wriggling among the leafy debris in the net.
These two “eft-phase” eastern newts were rescued from the authors pool skimmer
Upon returning to the house, it didn’t take long to identify the three-inch long specimen as an eastern newt. As I later read more in depth about this species, I learned that newts are in the family called Salamandridae and typically (not always) have three distinct life phases where they go back and forth between the land and water. After the eggs hatch, larval newts are fully aquatic, with a pair of feathery external gills protruding behind their head. As they mature, they metamorphose into a bright orange/red color and no longer have external gills. They then leave the water for a terrestrial phase where they are called “efts.” Efts may wander the forest floor for many years and travel long distances before once again returning to the water as an adult to breed. Back in the aquatic environment, they morph into a different looking creature yet again. The external gills do not return but the skin color goes from brightly colored to a greenish-yellow and the tail develops a flattened ridge that aids in swimming. All phases have tiny, bright red dots on the body that are circled by black rings, hence their other name, the red-spotted newt. The skin of the eastern newt is also toxic and scientists refer to the bright coloration of the eft as “aposematic” or warning coloration. Their toxicity allows this species to co-exist with fish, unlike some other salamanders that would become tasty snacks and not likely survive to adulthood. The eastern newt is widespread throughout eastern North America and has been intensely studied for its amazing ability to regenerate lost body parts. Not just limbs but even organ tissues!
So the next time you want to test whether or not you might qualify as a hardcore naturalist (i.e. certifiably nuts), take a nighttime trek into a dark, watery, scary place alone. Pay close attention to your reaction when something moves under your foot on the squishy bottom. I would wager that most of you would fall somewhere just shy of being a true hardcore naturalist. I would even put money on it. Have fun!