With several thousand acres of shallow water, it should come as no surprise that Goose Pond FWA is home to an abundant, varied, and highly interesting assemblage of aquatic macroinvertebrates. The prefix macro- means big enough to see without a microscope and the suffix invertebrate refers to their lack of a backbone. Hidden from the view of most visitors to GPFWA as they usually are, this group of animals is much underappreciated in terms of their highly fascinating life styles and importance in the web of marshland life.

Macroinvertebrate is a collective term for a diverse collection of insects, crustaceans, mollusks, and worms. The group includes animals such as aquatic insects (backswimmers, water boatmen, diving beetles, water bugs) and their larvae (dragonflies, mayflies, true flies), crayfish, freshwater snails, freshwater clams, flatworms, tubifex worms, and isopods. These animals are of major importance in aquatic ecosystems because they act as predators, nutrient recyclers, prey species for fish and birds, and indicators of water quality.

For this edition of Critter Corner, I would like to focus upon one macroinvertebrate that I find particularly interesting –  the giant water bug.  First, an explanation of the term bug. For the layman, the term bug connotes any type of creeping, crawling, or flying invertebrate. In this parlance, a bug could be any one of hundreds of thousands of insect species, It could be an arachnid such as a spider or scorpion or it could even be another arthropod such as a millipede or centipede. To the specialist however, the term bug means one thing. It is a member of a specific Order of insects known as the Hemiptera. Hemipterans, or true bugs, include familiar species such as stink bugs, assassin bugs, water striders and of course water bugs.

Giant water bugs are actually fairly common and, although the number of different kinds in the U.S. is not great, they are found throughout our country in the proper habitats. These include marshes, ponds, and lakes. Some species may also live in flowing water. Usually giant water bugs spend much of their time clinging vertically to submergent vegetation or hanging head downward from the water surface. Is these poses, they lie in wait for prey to come within range. Giant water bugs are aggressive, voracious predators. Should their intended victim come close enough, the giant water bug will attack by suddenly grasping the prey with its raptorial forelimbs. This term refers to limbs which are powerful and armed with spines or claws to better grasp prey. Giant water bugs are large enough to eat animals such as tadpoles and fish. Voshell’s guide to freshwater invertebrates refers to a captive giant water bug that caught and ate a pickerel 3.5 inches in length; an impressive feat for an insect that is usually somewhat less than three inches in length itself. There are even reports of giant water bugs attacking baby turtles and water snakes. When necessary, giant water bugs may also pursue their prey by swimming. They use their two pairs of flattened hind limbs like oars to swim

I’ve always thought that the giant water bug would make a fine subject for a science fiction film. After all, particularly among the radiation induced mutants of the 1950’s, we’ve been terrorized by ants, tarantuals, scorpions, grasshoppers, and wasps that treated humans like items from a snack bar. Why not the giant water bug? I find their feeding habits especially gruesome. The aforementioned J. Reese Voshell, Jr. notes that, should the prey be large, the giant water bug may ride it around as it waits for its poisonous salivary enzymes to take effect. A classic description of a giant water bug attack appears in Annie Dillard’s Pilgrim at Tinker Creek. Wandering pond-side one day, she happened to espy a frog sitting at water’s edge. As she gazed down upon the frog, “he slowly crumpled and began to sag. The spirit vanished from his eyes as if snuffed. His skin emptied and drooped; his very skull seemed to collapse and settle like a kicked tent.” Dillard noted that, “an oval shadow hung in the water behind the drained frog.” The hapless frog had been attacked by a giant water bug. Paralyzed by the bug’s venomous saliva, its innards thus liquefied, the little amphibian had no chance of escape from this voracious predator. Doesn’t sound like a very pleasant way to go does it? Thankfully such an attack upon a human is only the stuff of science fiction. But be aware. These insects sometimes feign death when one picks them up. They may suddenly “come to life” and deliver a powerful and painful wallop to the hand with their beak-like, piercing mouthparts. Handle with care!

Once, while leading a field trip at GPFWA, we netted a giant water bug that looked like the one pictured here (courtesy of Wikimedia). This is a male carrying an accumulation of eggs which the female has glued onto his back. Here the eggs are protected from predation by the ever-presence of the fierce father. He also aerates the eggs by gently stroking over them with his hind legs. Other species may glue their eggs onto underwater vegetation after which they abandon them.

Perhaps the strangest encounter I have had with giant water bugs occurred in Bangkok, Thailand many years ago. Strolling along in the grand market, I espied these young ladies plying their wares. Yes, deep-fried giant water bugs, a delicacy in some parts of Southeast Asia. It appears that humans, at least in some parts of the world, have turned the tables on these fierce, predatory macroinvertebrates.

**************************************************************

Interested in more about giant water bugs?

Milne, Lorus and Margery Milne. 1980. The Audubon Society Field Guide to North American Insects and Spiders. Alfred A. Knopf, New York.

Voshell, Jr. J. Reese.2002. A Guide to Common Freshwater Invertebrates of North America. The McDonald & Woodward Publ. Co. Blacksburg, Virginia.

https://www.eatingthaifood.com/how-to-eat-a-giant-water-bug-maeng-da-thailand/

photo 1 by Judy Gallagher [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

Critter Corner No. 21 – The Red Bat

by

George Sly

(photo courtesy So. Conn. St. Univ.)

A recent presentation on bats to a group of Sullivan Elementary School second graders reminded me that this was a group which has, up until now, been totally neglected in my Critter Corner blogs. Time to remedy that oversight! It would be difficult to find a mammalian group either more interesting in regards to their biology or more maligned by the uninformed. They deserve some positive public relations time.

Currently there are three species of bats known to occur at Goose Pond FWA. Biodiversity surveys have recorded the red bat, little brown bat, and eastern pipistrelle. Whitaker and Chamberlain ¹ speculate that the northern myotis, Indiana myotis, big brown bat, and hoary bat are also likely residents of GPFWA although they have not yet been recorded there.

Bats are members of the mammalian order Chiroptera. This name is derived from the Greek words meaning “hand and wing”. Indeed, examination of the skeleton within a bat’s wing reveals a pattern of bones and digits homologous with our own hand. The only substantial difference is that the phalangeal (finger) bones of the bat’s “hand” are exceptional long. Had we fingers like bats, we could sit in the recliner and change channels on the TV without the need of a remote. Stretched over these enormously elongated finger bones is a thin webbing of skin which serves to form the wings for flight, snagging insects from the air like a baseball player’s mitt, or enfolding the body while roosting. Bats are one of the few extant animal groups capable of true flight (birds and insects being the others) and are the only mammals which can do so. Flying squirrels, flying lemurs and other vertebrate called “flyers”, such as flying lizards, flying frogs, and flying snakes, are all gliders not true fliers.

There are around 1200 species of bats in the world. Upon venturing into the tropics one often finds nearly 50% of the mammalian fauna to be bats.  With an abundant, year-round insect supply, as well as many species of fruit bats (a group absent here) this isn’t surprising. Bats in general are divided into two suborders, one commonly called the insect-eating bats and the other the fruit bats. Although many members of the former group do eat insects – and are highly valuable economically  and ecologically as a result – other species of this suborder may be found which specialize in eating fish, frogs, nectar, pollen, other bats, and even blood. All of our Indiana bats (12 species) are insect eaters.

Bats range in size from the tiny bumblebee bat (aka Kitti’s hog-nosed bat) of SE Asia, which is only about an inch long and weighs less than an ounce, to the Pemba Island flying fox which has a wingspan of five feet and weighs over a pound.

Our red bat is about four or five inches long and weighs an average of about half an ounce. Like other insect eating bats, Lasiurus borealis uses echolocation to find its prey and to maneuver about in its environment.  This technique involves sending out extremely high-pitched sounds which are usually beyond our hearing range and, like sonar, reflect off of objects and potential food items and are returned to the bat’s ears. The returns are analyzed by the bat’s nervous system resulting in a detailed picture of its surroundings. See www.scientificamerican.com/article/how-do-bats-echolocate-an/ for an interesting explanation of echolocation, an amazingly complex ability. Most fruit bats, in contrast, do not echolocate and rely on eyesight to locate potential food and to maneuver through the rainforest. The anatomy of the insect eating bats and the fruit bats reflect this difference. The former tend to have very large ears and small eyes while the latter have small ears and quite large eyes. It should be noted that, even in the smaller eyed insect-eating bats, vision is good. The old saw about “blind as a bat” is but another example of how these creatures are misunderstood.

Red bats prefer scattered hardwood trees such as found in woodlots as their habitat. Their flight is rapid and they may forage for insects over water during which time they may also dive to the surface and drink as they skim along the water. Foods of the red bat include various kinds of insects such as moths, beetles, winged ants, plant hoppers, and flies. It is often suggested that bats are of great value in eliminating mosquitos. However the food habits studies shown in Whitaker and Mumford’s Mammals of Indiana² do not support this. In the eastern pipistrelle for example, less than 5% of its prey was comprised of mosquitos and, for the red bat, mosquitos were not listed as a prey item at all.

The reproduction of red bats is interesting in that mating occurs in late summer (Aug./Sept.) but most young are not born until June. This is due to the fact that, as with many other bats, sperm is stored after mating and fertilization does not occur until shortly after emergence from hibernation.  One hypothesis for this delay is that late summer is the optimum time for mating due to the abundant food/energy resources available from insects. However with winter approaching it is not a good time to be producing youngsters. Gestation in bats is longer than that of mammals of similar size (45 days versus 21 days in a mouse). As a result, the bat’s offspring are more well developed at birth. Delayed fertilization and longer gestation result in bat offspring becoming active in concert with warming weather and increased food availability. The fact that our bats typically have only one litter per year, and just one or two young per litter, tells us a couple of things about them. First, this makes it clear that they  are slow to regenerate lost numbers. Thus human vandalism of winter roosts can be devastating (not to mention the deadly white-nose syndrome which has spread steadily westward in the U.S.). This low reproductive rate also suggests that these bats are not subject to significant predation pressure. Their nocturnal habits and secluded roosts normally protect bats from predators. Although I did recently find a bat skull in an owl pellet I was dissecting, bats do not really fit the profile of the terrestrial prey these nocturnal birds normally take. Bats are only rarely taken by other nocturnal predators such as house cats, raccoons, skunks, or snakes. Adult bats can attain significant age. One age record for our little brown bat is 34 years³; compare this to a life span of one or two years in the typical field mouse.

Another interesting aspect of the biology of the red bat has to do with its winter habits. We typically think of bats going into a cave or building during the winter to escape the harsh conditions, and lack of food, by hibernating. Although some red bats may winter in Indiana they more typically migrate. This is a behavior we normally associate with birds. Nevertheless, most eastern red bats migrate to more southern latitudes of the United States where their insect prey remains abundant and active. Other Indiana bats that make significant migrations include the hoary bat and the silver-haired bat. Recent studies have shown that migratory bats are threatened by wind turbines. Interestingly enough, the bats are not injured by the blades; these are detected by their echolocation. Rather the moving turbines create areas of low pressure adjacent to the blades. When the bats fly into these low pressure areas their lungs rapidly expand causing fatal hemorrhaging and death by what is called barotrauma⁴.

Bats in general get a pretty bad rap from people. Stories of vampires, the danger of rabies, bats flying into people’s hair, and wanton attacks certainly haven’t done anything to improve the image of these little mammals. Vampire bats do exist but not north of Mexico (yet?) and they most assuredly don’t assume human form during the day. All mammals can theoretically carry rabies but only five or six percent of bats tested harbor the virus. Of course this is an extremely dangerous disease and a bite from a bat, although extremely rare, should be taken seriously with medical advice being sought. Myths regarding unprovoked attacks on people or dives into a well coiffured hairdo are simply tall tales. Contrast these with the important work bats do in controlling insect populations. The number of insects bats consume on a nightly basis are astronomical and many of these insects are economically harmful. For example big brown bats, one of the most common species in Indiana, like to feed upon chrysomelid beetles. The crop damaging corn root worm is the larvae of one of these beetles. Here is a species that is definitely the farmer’s friend. 

   The diversity of form and habits among the Chiroptera is simply remarkable. Their economic and ecological benefits are undeniable. In a world in which wild places and wild things seem to be in steady decline, these fascinating mammals need all the understanding and help we can give them.

1. 1. Whitaker, John O., Jr. and Angela K. Chamberlain. 2011. Mammals of the Goose Pond Fish and Wildlife Area Green County, Indiana. Proceedings of the Indiana Academy of Science 119(2):153–157
3. 2.Whitaker, John O., Jr. and Russell E. Mumford. 1982. Mammals of Indiana. Indiana University Press. Bloomington.
5. 3.Whitaker, John O., Jr. Virgil Brack, Jr., Dale W. Sparks, James B. Cope and Scott Johnson. Bats of Indiana. Center for North American Bat Research and Conservation. Indiana State University. Terre Haute.
7. 4. Erin F.Baerwald, Genevieve H.D’Amours, Brandon J.Klug and Robert M.R.Barclay. 2008. Barotrauma is a significant cause of bat fatalities at wind turbines. Online at Science Direct: Current Biology. www.sciencedirect.com/science/article/pii/S0960982208007513

Toads generally differ from frogs in that the skin of the former is drier, somewhat thicker, and often covered by warty projections in comparison to the thin, moist skin of frogs. The condition of the toad’s skin indicates to us that it spends more time away from water than the typical frog and is thus less likely to suffer water loss via the cutaneous surface. Particularly noticeable on the rough skin of the Fowler’s Toad are two large glandular structures on the head just posterolateral to the eyes. These are the parotoid glands which secrete a toxic substance meant to deter predators. I have seen dogs make the mistake of grabbing a toad in their mouth only to learn that the secretions of these glands make for a very unpleasant experience. Salivating, foaming at the mouth, and experiencing a burning sensation the dog learns a most memorable lesson about henceforth leaving toads alone.

   Like the frogs at GPFWA, Fowler’s toads lay their eggs in water where they develop into tadpoles. Toad eggs are laid in strands such as those of the American Toad shown below (L). Frogs (R) on the other hand tend to lay their eggs in clusters.

 

Of course the reproduction of Fowler’s Toad is, like other anurans, accompanied by loud and prolonged chorusing by the males. Such calls establish their micro-territories and attract females to their location. Fowler’s Toad calls are strange to my ear although pleasant. They have been described variously as bleats, screams, or a loud nasal “waaaaaah”. I suppose a bleating sound might most closely approximate what I hear. Even though the call has range, you must imagine the sound as if it is being made by a Lilliputian sheep of a size appropriate for a set of barnyard animal toys. The spring onset of chorusing by these toads from my neighbor’s pond just over the hill from my house is always a pleasing reminder that longer, warmer days lie just ahead.

Fowler’s Toads are a good example of the animals that we humans often take for granted or ask, “What good are they.” In fact they, like other anurans, are of extreme ecological value. They are important in controlling the populations of their prey species. Insects are the primary targets of toad predation. In addition, and in spite of their toxicity, toads serve as prey for other animals such as Garter Snakes, Hognose Snakes, and raptors. Tadpoles may be eaten by fish and predaceous insects such as diving beetles. Toads are, in other words, important components of what we often refer to as the “web of life” within natural areas.

Interestingly, we may have to begin to think of toads as having practical value for us as well. Today we are finding that the organic chemicals produced by many species of both plants and animals have very significant importance for us as human medicines. Think of vinblastine, a chemical derived from the Rosy Periwinkle, which has increased survival rates for childhood leukemia from 10% to 90%. Among animals, we now use viper venoms as anticoagulants and cone shell venom to produce the drug ziconotide used in the treatment of chronic pain. A recent article in the American Journal of Translational Research pointed out that toad venom has been used as a traditional medicine in Asia for many years. The article suggests that further research by pharmaceutical companies is needed to clarify the efficacy of toad venom in the maintenance of strong heart function, its possible antitumor and antivirus activity, anti-infection effectiveness, and its pain-relieving effects

So, stay tuned. In reference to the toads, the question of “what good are they” may yet yield some surprising answers.

(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4346519/) (www.sciencedaily.com/releases/2009/09/090924101638.htm) (www.sciencedirect.com/science/article/pii/S1567576910004108)

Critter Corner No. 19

(photo by Judy Gallagher – commons.wikimedia.org/w/index.php?curid=55331862)

Discussing the Fox Squirrel as a member of the GPFWA fauna may seem a bit surprising. After all, we normally associate the property with wetland and prairie habitats primarily. These are hardly the sorts of places one would expect to find an arboreal (tree dwelling) mammal. But with the DNR’s acquisition of 800 acres of wooded, post-mined property known as “1000 Islands” (which lies just north of GPFWA’s Main Pool West) we now have such squirrel-friendly habitat Goose Pond.

The Fox Squirrel is large as tree squirrels go. In fact, it is the largest tree squirrel in the eastern United States with a total length of nearly two feet and an average weight of around one and a half pounds. In this area, people often call this species by the common moniker of “red squirrel”. Indeed, the fox squirrels we encounter in SW Indiana do tend to be quite reddish in color. However, in NE Indiana there lives another species of arboreal squirrel which is more properly known as the Red Squirrel (Tamiasciurus hudsonicus). This little squirrel is only about half the size of the Fox Squirrel on average.

The Fox Squirrel is highly variable in coloration throughout its range which, east of the Mississippi, extends through most of the country save for a swath from North Carolina up through the New England states. The scientific name of this species – Scirurus niger – hints at this variability. The genus name refers to the habit of the squirrel of sitting with its tail used as a sunshade. “Skia” is from the Greek meaning shadow and “oura” means tail. The Greek skiouros became the Latin sciurus, meaning squirrel in both cases. The specific name “niger” is Latin for black. In the southern United States, Fox Squirrels may be black in color and the so-called type specimen for this species was a southern animal of black coloration. In southern Alabama, I used to encounter Fox Squirrels which were locally called “monkey-faced squirrels”. These animals were much lighter in color than our local fox squirrels, more light-brownish, and had a black mask which reminded me of a raccoon. The reasons for the extreme variability of coloration in fox squirrels is not completely understood but may be related to camouflaging coloration adapted for a particular locale.

Fox squirrels prefer more open forests and forest edges compared to our Gray Squirrel which thrives in large stands of timber with a closed canopy. However, both are adaptable and may be found in towns, upon golf courses, and in city parks. Fox Squirrel distribution is closely tied to food availability of course. Their diet includes a variety of tree nuts including acorns, hickory nuts, and beech nuts. Because of their habit of caching nuts in the ground, fox squirrels are important in distributing the seeds of their food trees. These buried stores are later found, by smell it is thought, and constitute the squirrel’s primary food supply during fall, winter, and early spring. As spring progresses, there is greater abundance of food and the Fox Squirrel will then feed on maple samaras, elm seeds, flower buds, and fruits such as mulberry. Fox squirrels will also prey upon caterpillars, beetles, bird eggs, and young birds. One of their more interesting food sources is a soil fungus of the genus Endogone. Dr. J.O. Whitaker, Jr., emeritus professor of life sciences at Indiana State U., has done much to elucidate the role of this fungus as a food source for many species of small mammals. Endogone is a mycorrhizal fungus which means that it forms symbiotic relationships with forest tree roots. This association is mutualistic in that it increases the absorptive surface area of the tree roots and in return the fungus is provided a place to live and a source of carbohydrates for energy.

Fox squirrels are typically about a year old when they begin to reproduce. Mating occurs in December and January. Living as I do on the edge of a stand of deciduous forest, I am each year reminded that the squirrel’s mating season is approaching. As I glance out the window, I will notice that the squirrels are beginning to engage in almost nonstop prenuptial chases which are an important part of the ritual leading up to actual mating. These are often accompanied by much barking, “churring”, and attempts at approach by the males. The gestation period of the Fox Squirrel is about a month and a half. One to six young may be born, most often in a tree cavity; two to four offspring is typical. The emergence of the youngsters after a period of three months or so is another source of entertainment for me (or maybe I am just easily entertained). At first the young squirrels tend to stay in the vicinity of their nest cavity. Soon they become bolder and start to venture higher into the trees. I often see them seemingly at rest, on the trunk or limb of a tree, when suddenly they roar off along the limb or into the tree top as if suddenly touched with a cattle prod. I suppose this is how they develop their marvelous skill at climbing, leaping, and maintaining a foothold while avoiding a precipitous fall.

In regards to its relationship with humans, the Fox Squirrel has long-standing significance as a small game mammal. Hoosier hunters take, on average, some 300,000 Fox and Gray Squirrels each year. I must say that the periods I spent as a young adult pursuing these agile, wily, little animals are among my fondest memories. And these remembrances involve far more than shooting at quarry. I must admit however that my recollections also entail a wonderful meal of fried squirrel, biscuits and gravy dotingly prepared by my grandmother.

But, as I grew older, the taking became far less important than the engaging. This was particularly true of the instances during which my stalking skills were tested against a mammal whose eyesight and senses of smell and hearing bettered mine by far. Even more fondly remembered are the hours spent simply sitting at the base of a shagbark hickory in an early -morning woods. Recalled is the light of breaking dawn playing upon forest leaves of every imaginable shade of green; the pleasurable songs and calls of phoebe, wood thrush, and great-crested flycatcher; the occasional, rustling walk of an unaware white-tailed deer passing within feet of me. These, as well as the deep sense of peace and detachment from worldly concerns, are the things that most remain from my days as a dedicated pursuer of squirrels.

Should you be inclined to try squirrel hunting yourself, the Dept. of Natural Resources offers these reminders. The season for both Fox and Gray Squirrels runs from August 15^th, 2017 through January 31^st, 2018. Hunters must meet fluorescent orange clothing requirements while hunting squirrels from the first Friday in November after Nov. 3 through the end of the season. The daily bag limit is five. Good luck on your hunt! But don’t forget to spend some of your time sitting under that hickory tree, looking, listening, and letting your mind work the while.