Sunday, January 21, 2018

An Assortment of Beetles

For as long as I can remember, I've loved arthropods. Arthropods come in so many different shapes, sizes, and colors, and even one group can exhibit an incredible amount of variation. One has to look no further than the beetles to see this in action. Beetles are insects that belong to the order Coleoptera, and there are a ton of beetle species out there. An inconceivable amount really. Just how many beetle species do we know about? There are currently 400,000 described species of beetles in the world, which accounts for around 25% of all the described species on Earth. For comparison, there are only about 5,400 described species of mammals in the world, and only about 10,000 described species of birds in the world. And that 400,000 number only accounts for the described species of beetles, which means the individual species some scientist has officially described as a species separate from the others. That number isn't including all the species we currently don't know about. Some scientists have estimated that there might be a total of 1,000,000 to 2,000,000 beetle species in the world, meaning there are hundreds of thousands of species out there waiting to be discovered and described!

Beetles exhibit a tremendous variety in both appearance and lifestyle. Some are all black, while others can resemble a rainbow. Some are carnivorous, while others are herbivorous, while even some others are omnivorous. Some are solitary, while others are relatively social. Some beetles provide parental care, and some navigate their landscape using the stars. Much of the allure of beetles lies in the sheer diversity regarding every part of their biology.

Despite the variety in form and function of beetles, I've never really spent too much time looking at their world. I have, however, collected many pictures of beetles over the past 5 years, and so I've finally decided to dive in and write up a post on a few of those species. This post is organized by family, so let's jump in to one of the more speciose families.


Chlaenius aestivus
The family Carabidae—whose members are commonly called the ground beetlesis incredibly diverse, with over 40,000 described species. Many of the Carabids are darkly colored, but a good number are colorful and metallic. One such example is the species pictured above, Chlaenius aestivus. Because there are so many species of beetles in the world, many of them do not have common names, instead only having a scientific name. Chlaenius aestivusas well as many of the other species included in this postdoes not have a species-specific common name, but the collective common name for members of the genus Chlaenius is "metallic ground beetle." The name is rather fitting, isn't it?

Eastern Red-Bellied Tiger Beetle, Cicindela rufiventris
My favorite group within the family Carabidaeand the beetles as a wholeare the tiger beetles. Although there are over 2,600 species of tiger beetles described in the world, the US and Canada is home to only about 117 species. The most recognizable species in Ohio is without a doubt the vibrantly-green Six-Spotted Tiger Beetle, but I want to talk about two other species. First up is the Eastern Red-Bellied Tiger Beetle, Cicindela rufiventris. I came across this individual while visiting Steve Willson's Blue Jay Barrens in Adams County, Ohio. As a side note, Steve operates a fantastic blog on the nature and management of the cedar barrens on his property. You can read his blog at Blue Jay Barrens! As with many other tiger beetles, the Eastern Red-Bellied Tiger Beetle prefers sunny openings in forests which can occur along ridgetops, near rock outcrops, and in recently disturbed areas.

One-Spotted Tiger Beetle, Cylindera unipunctata
Another tiger beetle which calls Ohio home is the One-Spotted Tiger Beetle, Cylindera unipunctata. I found this individual after it came to the lights during a mothing night at Clear Creek Metro Park in southeast-central Ohio. When it comes to the world of arthropods, tiger beetles are fearsome predators. They are lightning-fast, and the fastest speciesCicindela hudsonican reach speeds up to 5.5 miles per hour. Proportionally, if humans could run that fast, we would be running at speeds around 225 miles per hour! In addition to their speed and agility, they also have large, formidable jaws that can easily clamp onto a prey item, such as other beetles, small flies, and a host of other arthropods.


Neopyrochroa flabellata
This orange and black beetle is Neopyrochroa flabellata, one of the flame-colored beetles of the family Pyrochroidae. Contrary to what one might assume, the reproductive habits of insects can be much more complex than "find a live individual of the opposite sex and mate." And N. flabellata has a rather fascinating love life. Many animals love to eat eggs; eggs are little bundles of protein and nutrients which don't fight back. Normally, at least. When female N. flabellata's lay their eggs, they cover the eggs in a protective compound called cantharidin. Cantharidin is a blistering compound that causes burns when applied to the skin of an animal, and can poison an animal in large enough doses. As such, covering your eggs in cantharidin would ensure that no one else messes with them. The problem is, N. flabellata can't make their own cantharidin.

So how does the female get it for her eggs? Well that's where the males come in! The job of the male is to find and consume enough cantharidin, and then approach the female. Upon approaching a female, a mating ritual will ensue. The two beetles will face each other, head to head. The male will begin to secrete part of his cantharidin reserve from a special gland found on his head, and the female will use her antennae to sense whether the male does indeed have any cantharidin, and if so, does he have enough. If he lacks it all together, he will almost surely be rejected. If he has some, but not a lot, he runs the risk of being rejected as well. If the female thinks he male has enough, she will then signal that she is willing to mate. During the mating process, the male transfers his cantharidin to the female, who will then coat her eggs with it.

Where does the male get the cantharidin, you might be wondering? That's a good question, and there's some uncertainty when it comes to the answer. Cantharidin is a rare substance in nature, and only two groups of beetlesthe blister beetles of Meloidae and the false blister beetles of Oedemeridaecan synthesize it themselves. It is currently assumed that male N. flabellata individuals will seek out blister beetles and either kill and eat parts of their body to accumulate the cantharidin, or that they scavenge on dead blister beetles to get the cantharidin. There's a few issues with this premise, as Thomas Eisner et al. points out in their 1996 paper on the subject. First, it hasn't been recorded that N. flabellata feeds on adult insects, such as the blister beetle. Second, blister beetles and false blister beetles rarely occupy the same habitats that N. flabellata occupies. And lastly, it seems unlikely that there are enough blister beetles out there to satisfy the need of N. flabellata individuals. The question of the source of the canthardidin highlights the lack of often basic information we have on so many of our arthropod species.


Ceruchus piceus
As I mentioned with the previous beetle, we are lacking a lot of the "basic" facts when it comes to most of the arthropods on Earth. Take, for example, the beetle above. This is a Ceruchus piceus. There isn't a lot that's known about Ceruchus piceus, especially when it comes to random interesting facts. It is worth pointing out that the individual pictured is a male, as can be told by its large mandibles. This species belongs to the family Lucanidae, which is commonly known as the stag beetles. As male deer have a part of their body enlarged to attract females and fend off other males, so too do male beetles of the family Lucanidae. Male deer have antlers, but male stag beetles have large mandibles. These mandibles are used to attract females, fight other males, and defend themselves from potential predators. 


Grapevine Beetle, Pelidnota punctata
It wouldn't be a post about beetles without throwing in one of the scarab beetles. A few scarab beetles—which are simply beetles of the family Scarabaeidae—are well-known to humans. May Beetles (AKA June Bugs), Green Fig Beetles, and dung beetles are all different types of familiar scarab beetles. But my favorite scarab beetle is one of the lesser-known species. Meet the Grapevine Beetle, Pelidnota punctata. The Grapevine Beetle is a large and relatively common species across the eastern US, but one that not many are familiar with. That is unless you happen to be a moth-er, as Grapevine Beetles love to come to mercury vapor lights. As the name suggests, the adults of this species feed on the various species of wild and domesticated grapes found throughout the eastern US. Despite this, the Grapevine Beetle is not considered a significant pest species. 


Milkweed Leaf Beetle, Labidomera clivicollis
In my opinion, one of the most under-rated families of beetles is Chrysomelidae. Chrysomelids—more commonly known as the leaf beetles—are beetles that feed exclusively on plants. Generally speaking, they are relatively small, round, and oftentimes colorful. Take, for example, the Milkweed Leaf Beetle, Labidomera clivicollis. As the name implies, this species feeds on various milkweed species, especially Swamp Milkweed, Asclepias incarnata. Like the Monarch butterfly and other insects which feed on milkweed, the Milkweed Leaf Beetle sequesters the cardenolide toxins found within the plant for defense. And as with the Monarch, the Milkweed Leaf Beetle has a colorful and contrasting orange and black coloration to warn predators of its poisonous nature. 


Eutrichillus biguttatus
Beetles in the family Cerambycidae are almost always attention grabbers. Species of this family are collectively called long-horned beetles—and often for obvious reasons. As the Eutrichillus biguttatus individual pictured highlights, the Cerambycids typicallyalthough not alwayshave long antennae that are normally as long as their body. Sometimes, such as with E. biguttatus, the antennae are much longer than their bodies. 

Elm Borer, Saperda tridentata
Although some of the long-horned beetles are subdued in color for camouflage, others can be fantastically colored. Take the Elm Borer, Saperda tridentata, for example, with its flame-colored oranges contrasting with its deep black. Long-horned beetles often get a bad rap among us humans, as many of their feeding habits result in them being labelled pests. Generally speaking, the larvae of long-horned beetles feed on wood. Depending on the long-horned species in question, this wood can be dead wood or—as in the case of the Elm Borerlive wood. For the species whose larvae feed on live trees, an infestation can result in the direct or indirect death of the tree. Of course, this might upset some people when the tree in the yard dies, but all is part of the natural balance within a forest (except, as I should point out, when it comes to non-native invasive long-horn beetle species. Such invasive species can cause significant harm). The native Elm Borers, for instance, almost always choose weak, broken, or sickly elm trees to lay their eggs in. Healthy elm trees are apparently left alone. With such a lifestyle, Elm Borers are actually inadvertently culling sickly elm trees from the forest while leaving the healthy individuals to proliferate.


American Burying Beetle, Nicrophorus americanus
The most exciting beetle I've seen my entire life has been—without a doubt—the American Burying Beetle, Nicrophorus americanus. The American Burying Beetle is a federally endangered species which has all but disappeared from its range across the eastern and central US. I learned about it years ago, and never thought I would get to see one because of how rare it is. However, I was lucky enough to visit The Wilds this past summer and help with a reintroduction of over 200 captive raised individuals. Not only did I get to see American Burying Beetles, but I also got to hold some! I have an entire post up on the strange life cycle of the American Burying Beetle, some of the most current thoughts as to cause of the decline of the species, and the reintroduction efforts by The Wilds. You can find that post right here at this link!

Nicrophorus pustulatus
Typically, I end my blog posts with the species I was most-excited to see, but not this one. Today, I will end with a species who has evolved a lifestyle unlike all of its cousins. Meet Nicrophorus pustulatus, another member of the burying beetle family. Like the previous American Burying Beetle, almost all burying beetles (genus Nicrophorus) follow the same general reproductive pattern: First, they find a carcass of some sort, then they bury that carcass within a chamber underground, then they modify the carcass into a meatball covered in anti-fungal anal secretions, and then they feed parts of that carcass to their young, which they laid in a chamber right above the carcass-ball. But not N. pustulatus. This species has evolved a rather remarkable alternative lifestyle. Nicrophorus pustulatus is a parasitoid of snake eggs. A parasitoid is a specific kind of parasite that actually ends up killing its host. Parasitoids are extremely common in the invertebrate world, but they all utilize other invertebrate as hosts. Nicrophorus pustulatus is the only invertebrate parasitoid currently known of in the world whose host is a vertebrate!

In the early 2000's, a team of scientists kept noticing that the Black Rat Snake nests they were finding regularly contained both adult and larval N. pustulatus individuals. Within these nestswhich often contained many separate clutches of eggs as these snakes regularly nest communally—many of the eggs had been obvious consumed. When the team of scientists looked into this phenomenon, they realized that no one had ever documented N. pustulatus burying carcasses before in nature, and they began questioning whether there was something unusual going on. They soon found that if you raise N. pustulatus individuals in the lab, and give them a dead mouse, they will bury that mouse, but they seemingly didn't do so in nature. A few studies later (the original in 2000 and a confirmation in 2007), and it can safely be said that N. pustulatus is indeed a parasitoid of snake eggs, a wholly new and remarkable phenomenon in the natural world!

Last fall, I purchased a macro lens with the intent to take more detailed photos of various arthropods, and hopefully I will take many more photos of beetles. If I do, you'll surely see some more posts on this diverse group! Thanks for reading!

Wednesday, January 10, 2018

Longleaf Pines Forests and Red-Cockaded Woodpeckers

Longleaf Pine Forest

Let me throw some statistics at you. Prior to the European colonization of the United States, there was an estimated 90,000,000 acres of Longleaf Pine forest in the southeastern US. This Longleaf Pine forest ecosystem covered most of the Atlantic Coastal Plain from Virginia to Texas. Nowadays, of those 90 million acres, only 3,400,000 remain. That's only a whopping 4% of what it used to be. Of those 3.4 million remaining acres, only approximately 12,000 acres can be considered old growth Longleaf Pine forests. That's a mere 0.4% of the remaining 4%.

North Carolina Longleaf Coalition
Map of the Longleaf Pine forest historical range. Map courtesy of the North Carolina Longleaf Coalition.

As one might guess, the nearly wholesale destruction of the Longleaf Pine forest ecosystem had an incredibly negative impact on many of the animals which called this ecosystem home. Although some of the animals that lived in Longleaf Pine forests also lived in other ecosystems—say, for example, White-Tailed Deer and the Common Raccoon—many others were dependent on this ecosystem. And as the ecosystem became endangered, so did many of the animal species that were intrinsically tied to the ecosystem. Such animals include the Gopher Tortoise, Indigo Snake, and—most famously—the Red-Cockaded Woodpecker.

Santee Coastal Reserve Wildlife Management Area

Back in October of 2017, I ventured to the Santee Coastal Reserve Wildlife Management Area in Charleston County, South Carolina. This 24,000-acre wildlife management area (WMA) contains an assortment of different habitats, including salt marshes, freshwater swamps, barrier islands, and an extensive old growth Longleaf Pine forest. The Santee Coastal Reserve WMA was officially established in 1974, but the forest is much older. Prior to the acquisition of the land by the state of South Carolina, the forest and surrounding lands were privately owned. For the majority of the 1900’s, the land belonged to a hunting club, which managed the land for various game species, especially waterfowl. The natural stand of Longleaf Pine forest pictured above was essentially left alone, and it is now well over 100 years old. Presently, visitors to the Santee Coastal Reserve can drive the dirt roads that wind through the Longleaf Pine forest, hike along old rice plantation dykes that crisscross a salt marsh, or meander down a boardwalk that snakes its way into a Bald-Cypress swamp.

Longleaf Pine needle length
A 16-inch long needle.

Before we talk about the Red-Cockaded Woodpeckers that call Santee Coastal Reserve home, let's talk about the Longleaf Pine forest. As the name suggests, a Longleaf Pine forest is a forest in which the dominant tree is the Longleaf Pine (Pinus palustris). The Longleaf Pine is named as such due to the incredible length of its needles, which can reach up to almost 18 inches!

Longleaf Pine grass stage

The Longleaf Pine doesn't grow like a "typical" tree. When you think about the life cycle of a typical tree—say a White Oak or Sweetgum—the seed will sprout a sapling. That sapling will look like a miniature version of the adult tree—with fewer leaves and the like. That sapling will then grow in both girth and height, and more branches and leaves will be added. But Longleaf Pines go about growing a bit differently. When a seed sprouts, the resulting individual doesn't look like a tiny tree, but instead looks something more akin to a sedge or clump of grass. In fact, this part of the Longleaf Pine's life is called the "grass stage," and the individual pictured above is one such example. Longleaf Pines will stay in this grass stage for 1 to 12 years. During this period, they really don't grow upward. They instead focus on growing an extensive root system.

Longleaf Pine bottlebrush stage

After the grass stage, the individual will quickly shoot up a few feet, but will still not grow any branches. This stage is called the bottlebrush stage, and the individual pictured above is in this stage. After a few more years in this stage, the individual will begin growing taller and will finally start growing branches. Only at this point will the individual be considered a sapling.

Longleaf Pine pinecone

Around the age of 30 or so, the tree will begin producing pine cones, which are huge compared to most of the pine cones this Ohioan is used to seeing. Earlier I mentioned how the Longleaf Pine forest ecosystem nearly all but disappeared from the landscape. There are two main reasons for this. First and foremost, many a Longleaf Pine found its fate in the form of an axe or saw in the 1700's and 1800's. The Longleaf Pine can grow upward of 150 feet tall, and nearly 4 feet in diameter, making it especially attractive to the early American logging industry. An unbelievable number of Longleaf Pine stands were clearcut, and instead of replanting these stands with more Longleaf Pines, loggers and landowners mostly replanted the land with Loblolly Pines, which grow much faster. This faster growing rate meant a faster turnaround in profits for loggers. Most of the forests which were once dominated by Longleaf Pines are now dominated by Loblolly Pines, and those forests will remain that way unless someone steps in and properly manages the forest.

Longleaf Pine forest fire

The second reason for the decline and destruction of Longleaf Pine forests lies in the cultural push for fire suppression. Forest fires are a natural feature in nearly all the forests types throughout the US, although they vary in the rate of incidence. Some forest types, such as the eastern deciduous forest ecosystem, will experience a forest fire every 100-400 years on average. Other types of forests experience natural forest fires very often; the Longleaf Pine forest ecosystem historically experienced natural forest fires every 2 to 3 years. These natural wild fires were started by lightning, but—as I discussed in my previous post about the I'OnSwamp—Native Americans and even early European colonists exacerbated this natural rate by utilizing forest fires as a tool for altering the landscape. However, by the late 1800's and early 1900's, a cultural shift occurred in the US. Forest fires of any type, whether natural or set by humans, were considered dangerous and unnatural. Forest fires were suppressed as best they could be, and a bear dressed in human clothes hammered into the impressionable minds of American children that only they could prevent forest fires.

The problem is, most forested ecosystems are meant to burn in some form or another. The Longleaf Pine forest ecosystem must burn for its existence to continue. If all fires are suppressed, the plants in the undergrowth of a Longleaf Pine forest will begin to grow up, and eventually other tree species will crowd out and ultimately replace the Longleaf Pines. As it turns out, Longleaf Pine trees are nearly fire resistant, whereas other plants in this region are not as resistant to fire. In a Longleaf Pine forest's natural state, with fires occurring every 2-3 years, the Longleaf Pines will remain strong and healthy while other bushes and trees are repeatedly burned back. The Longleaf Pine can only maintain its grip in this ecosystem with fire being a common occurrence. Thankfully, we have come to realize that forest fires are a necessary component in many ecosystems, and many of the remaining Longleaf Pine forests are actively managed with low-intensity prescribed burns every few years.

Red-Cockaded Woodpecker and Longleaf Pine Forests

The quality of a given Longleaf Pine forest is of utmost importance for many of the animals and plants which call it home. Take, for example, the Red-Cockaded Woodpecker. The Red-Cockaded Woodpecker is a Federally Endangered species, and there are only an estimated 15,000 individuals left in the world. The disappearance of this species is tied directly to the disappearance of the Longleaf Pine forest from across the southeastern US. The Red-Cockaded Woodpecker relies almost exclusively on the Longleaf Pine nesting. And not any Longleaf Pine will do; no, the Red-Cockaded Woodpecker needs relatively old Longleaf Pines. When Longleaf Pines reach about 60 or so years old, a fungus will often infect the tree and cause Red Heart Rot. With this fungal disease, the heartwood of the Longleaf Pine will soften. Only in the softened heartwood of an infected Longleaf Pine tree can a Red-Cockaded Woodpecker build its nesting cavity, as it is otherwise too hard for the woodpecker to carve.

Red-Cockaded Woodpecker White Tree Band

Not unexpectedly, Red-Cockaded Woodpeckers used to be common throughout the original 90 million acres of Longleaf Pine forest, with an estimated 2-4+ million individuals total at the time of European colonization. And, also not unexpectedly, their numbers plummeted as the Longleaf Pine forest was cut down and converted in the 1700's to 1900's. When the Red-Cockaded Woodpecker was officially added to the Endangered Species List in 1979 (5 years after the Endangered Species Act was created), there were less than 10,000 individuals remaining, which was less than 1% of their historical population. Intensive conservation efforts were put in place to save the species. States started restoring and actively managing Longleaf Pine forests to expand available habitat for the Red-Cockaded Woodpecker. Officials began surveying forests for individuals and marking active nesting or foraging trees with white bands, so active "clusters" of Red-Cockaded Woodpeckers could be monitored year to year. These bands also allowed public and private landowners to know which trees to not cut down or tamper with. Officials also began creating artificial nest cavities in younger trees that Red-Cockaded Woodpeckers could not carve into, allowing them to nest more readily in forests that might not be "up to par" when it comes to the age factor.

Thankfully due to these intensive conservation efforts, the Red-Cockaded Woodpecker population has been recovering. A 2016 survey estimated the total population to be around 15,000 individuals and growing. And although their numbers are increasing, they are still listed as Federally Endangered, and probably will be for some time. The greatest threat to the individuals nowadays is continued habitat fragmentation and weather events. A large hurricane, for example, could wipe out nesting-age trees and individual woodpeckers themselves. When Hurricane Hugo made landfall in South Carolina in the fall of 1989, the winds toppled 87% of all the trees containing active Red-Cockaded Woodpecker cavities in Francis Marion National Forest, which then held the largest population of the species. With a population already highly fragmented, such events can easily knock out entire local populations or harm them enough to where they are no longer viable. Isolated and fragmented populations are much more at risk of extinction than highly connected and broadly spaced populations.

Red-Cockaded Woodpecker Santee Coastal Reserve

The continued population growth of the Red-Cockaded Woodpecker is a welcomed sight. These little woodpeckers are considered "keystone species.” A keystone species is a species that interacts with its environment in a way that either regulates or has a significant impact on many of the other species within that same environment. In the case of the Red-Cockaded Woodpecker, upward of 27 other vertebrate species, and many arthropod species, utilize old Red-Cockaded Woodpecker nest cavities in some form or another. Many of these species—including Eastern Bluebirds, Brown-Headed Nuthatches, and Wood Ducks—require such cavities to breed, but are unable to create the cavities themselves. Such species rely on the Red-Cockaded Woodpecker to create suitable cavities, and the extinction of the species would have a cascading effect on many other species within the Longleaf Pine forest ecosystem.

If you want to see a Red-Cockaded Woodpecker species yourself, one of the best places to visit is the Santee Coastal Reserve WMA. Not only is this WMA renowned for birding in general, but the Carolina Bird Club claims that “Many birders have gotten their lifer Red-cockaded Woodpeckers and Bachman's Sparrows” in the old-growth Longleaf Pine forest within the preserve. Regardless if you’re a birder, a herper, a botanist, or just someone who enjoys nature, a visit to Santee Coastal Reserve is not one you’ll regret.