Thorn Bugs in South Florida

Thorn bugs (Umbonia)

Photos taken at Estero Bay Preserve State Park two weeks

Ideology trumps science

Quotes from a state environmental protection agency: "Why would we include things we don't agree with? That's ridiculous," Saenz said. "We were looking at not including very controversial things that are unsettled science."

and

"It isn't censorship to accurately report in our document what we believe. That's being responsible. That's being accurate"

I'm thinking the citizens may want to have an independent contractor run some water quality tests - there's obviously something in the water in Texas...

Article from Reuters:

The leaders of the agency, the Texas Commission on Environmental Quality, are appointed by Republican Governor Rick Perry, who said in a recent presidential debate that the science of climate change was "unsettled."

At issue is "The State of the Bay 2010" report commissioned by the Texas Commission on Environmental Quality, which has come under scrutiny after Rice University Professor John Anderson said that an article regarding sea-level changes he contributed was censored for political reasons.

Democratic state Senators Rodney Ellis of Houston and Leticia Van de Putte of San Antonio wrote to Perry appointee Bryan Shaw, chairman of the commission.

In his letter, Ellis said he concluded from the deletions that "the facts simply proved inconvenient to the agency and other state leadership, and thus they were excised."

The commission said on Monday it would remove Anderson's article on sea-level rise in Galveston Bay from the report, ending a standoff with Anderson over the deleted information.

Commission spokesman Andy Saenz said Anderson prematurely revealed the draft report to the media without prior approval, and that the commission did not want to include controversial implications about global warming in the report.

"Why would we include things we don't agree with? That's ridiculous," Saenz said. "We were looking at not including very controversial things that are unsettled science."

Two co-editors of the project, Jim Lester and Lisa Gonzalez, scientists with the Houston Advanced Research Center, a nonprofit research facility contracted for the report, asked the agency to remove their names, fearing their own credibility.

Lester, the center's vice president, called the deletions "scientific censorship." He said Anderson's statements in the article were not political and were reviewed by lower-level staff at the agency before upper management made its own edits.

"As a scientist, my main concern is about the availability of objective science for decision-making in agencies," Lester said.

Saenz denied the claims of scientific censorship.

"Using a word like censorship is very powerful," he said. "It isn't censorship to accurately report in our document what we believe. That's being responsible. That's being accurate."

Saenz said the agency was preparing a response to the senators. The agency, which is embroiled in a lawsuit with the Environmental Protection Agency over greenhouse gas emissions, has been working on the report for more than two years, the agency said.

FROM REUTERS:

http://www.reuters.com/article/2011/10/20/us-climate-change-texas-idUSTRE79J0DW20111020

Fuzzy pictures of fuzzy spiders

The southern house spider (Kukulcania hibernalis) is a sexually dimorphic species of crevice spider (Filistatidae). Both the female and male have fine, light-colored hairs on their abdomen and both have been documented as employing autotomy as a defensive tactic.

These were photographed on my car port earlier this week (same male in both pics, two different females):

The brown recluse looking specimen is the male; the female is larger and darker.

What kind of crap is this?

What kind of crap is this anyway?

I’ll give ya a couple hints:

The critter that left it behind lives in Florida, can weigh over 240 lbs, and it is a member of the order Carnivora…

It’s from a Florida Black Bear - Ursus americanus floridanus!

Usually their crap looks a little more like this:

But I guess you never know what you might find when you start digging through another’s crap…

King snake – It’s what’s for dinner!!!

Both of the above pictures were taken near Ft. Walton Beach, Florida a couple of months back.

Two is a company...

Anyone who has ever shared a residence can attest to the fact that cohabitating with others can be an extremely stressful state of affairs. Disputes resulting from a lack of privacy, the unequal sharing of common resources, and poor communication become routine occurrences. Even worse is a cohabiting situation in which those sharing the living space develop a mutual love interest – how does that get resolved? Luckily, a recent study published in an animal behavior journal may offer a glimpse of hope for those truly desperate for resolution.

Weighing as much as fifteen pounds and often sporting wingspans greater than nine-feet, bearded vultures (Gypaetus barbatus) are truly massive birds. First described by the father of modern taxonomy ( Carl Linnaeus) in his Systema Naturae, bearded vultures can be found competing for habitat throughout the mountainous regions of Europe, Asia and Africa. Even though a pining for expansive views has lead these bulky buzzards to prefer out-of-the-way nesting sites in hight rocky crags, pressure from human encroachment has caused their numbers to decline in recent years. The huge birds are experiencing population growth in a few isolated locales in the Pyrenees Mountains, but, unfortunately, the increase in the Pyrenees groups has contributed to overcrowding and a lack of housing options for many of the birds.

Under normal circumstances, in un-congested habitats, a bachelor bearded vulture will stake claim to a territory and take-up with a female member of the species; however, with the current surge in population in the Pyrenees, there simply isn’t enough available precipitous homesteads for all of the free-roaming males to settle down and raise families of their own. Lacking options, the roving males have developed a new strategy: they have begun to invade the established territories of their rivals – their already attached rivals. The itinerant bachelor invades the home of another male and claims residence with him and his already courted female companion. As might be predicted, the addition of an interloping male into the love nest of an established male-female pair has proven to adversely affect the reproductive success of the mate-pair.

Typically, a bearded vulture male-female pair will breed between the months of December and February and produce one or two eggs annually; but, the addition of the second male in the territory decreases the frequency and duration of the pair’s copulations. This occurs for a couple of reasons; firstly, the two males constantly fight each other for access to the female. The time and energy the males expend in combating and deterring one another leaves both far too exhausted to apply any romantic effort towards the female. Exasperating this situation even further, when one male does find the rare opportunity to copulate with the female, the rival male will often physically interrupt the act – he’ll stop them mid-coitus!

In addition to the mood-ruining intrusion of a combative third party during attempted sexual congress, the female can even be put-off by the mere presence of a second male — she’ll terminate copulation if she even spots a voyeur.

Fortunately, there is hope for the Pyrenees populations. As with the cliché, “time heals all wounds,” it turns-out that over long periods of time, the polyandrous model can work for the bearded vulture. Apparently the key to success in the multi-male regime is a willingness of the beta bird to demonstrate submission to the alpha – male on male copulations appear to curtail the aggression of the frustrated vultures.

Journal Reference:
Bertran, J., Margalida, A., & Arroyo, B. (2009). Agonistic Behaviour and Sexual Conflict in Atypical Reproductive Groups: The Case of Bearded Vulture Polyandrous Trios
Ethology, 115 (5), 429-438 DOI: 10.1111/j.1439-0310.2009.01628.x

A Threatened Orchid

Stenorrhynchos lanceolatum, the leafless beaked orchid, is listed as a Threatened species in Florida. This hummingbird pollinated orchid is found throughout Florida, Puerto Rico, and Central America.

Snapshots taken this past summer near Bradenton, Florida.

Transgenic Veggies Go Wild

A newly published study from Penn State details what can happen when a genetically modified organism escapes from captivity and interbreeds with the wild members of its species.

Transgenic organisms are critters that have been genetically engineered to express characteristics unique to their species. By snipping, swapping and splicing DNA between different species, organisms can be designed to provide specific benefits to people. For example, bacteria can be engineered to synthesis human insulin for treating diabetes, tomatoes can be manipulated to have an improved shelf-life, and pigs can be designed to more efficiently digest phosphorus, thus easing both their own cost of feeding and the amount of phosphorus pollution discharged into the surrounding environment. But, despite the potential benefits to people, what trouble could ensue if a transgenic organism were to evade human controls and escape its confinement? Would the transgenic organism out-compete the wild type and push it to extinction?

Cucurbita pepo is a species of squash cultivated around the world as a popular food; common varieties of the species include the zucchini, yellow squash and gourd. In addition to being commonplace at dinner tables, Cucurbita also maintains fame as a widely utilized transgenic plant – a transgenic plant that has managed to pass its transplanted genes to wild populations.

Prior to their escape, the genes of the Cucurbita plant had been engineered to have resistance to a leaf-wilting virus transmitted by aphids. The reasoning behind the genetic transplant was simple, by reducing susceptibility to the aphid borne disease, the agricultural yield of squash could be increased and more humans could be fed; but, having escaped, would the disease-resistant plants replace their naturally more disease-susceptible counterparts?

Not necessarily.

According to a case study just published in the November issue of the International Journal of Plant Sciences, when mixed populations of transgenic and wild type squash were naturally exposed to the aphid borne disease, the transgenic members did indeed exhibit better health – at least at first. After initially showing better health, the condition and reproductive success of the transgenic squash later equalized and balanced to that of the non-transgenic type. The reason for the equalization was that the robust appearance of the transgenic plants attracted the attention of leaf-munching, and bacteria-transporting, beetles. The beetles’ preference for the healthy looking plants affectively buffered any benefit the plants received from their introduced viral resistance.

Sasu, M., Ferrari, M., & Stephenson, A. (2010). Interrelationships among a Virus-Resistance Transgene. International Journal of Plant Sciences, 171 (9), 1048-1058 DOI: 10.1086/656531

Field Photos: Eastern Coachwhip Snake

Masticophis flagellum flagellum - the eastern coachwhip

Photographed near Inglis, Florida two weeks back.

Field Photos: Fishing Spider in Nyssa Swamp

The fishing spider Dolomedes tenebrosus as found in a Nyssa swamp near Tallahassee, Florida.

Snapshots taken about a month ago.

Alfred Russel Wallace, a Conspicuous Caterpillar and David Bowie

Prior to yesterday morning I had never contemplated the linkages between rock’n roller David Bowie and the co-founder of Natural Selection Alfred Russel Wallace. It turns-out that these famous Brits hold at least two things in common; the first and most obvious of which is the already mentioned fact that both Wallace and Bowie were born in the U.K. The second linkage between the two, as strange as this may sound, is caterpillars!

Yes, caterpillars!

The Bowie-Wallace-caterpillar connection became apparent to me yesterday morning as I was heading off to work. While stepping outside in route to the car, I noticed a rather strange looking creature attached to the exterior of the door frame (no, it wasn’t David Bowie!). In trying to figure-out what the creature was, my brain struggled to match its distinctive shape, color and pattern to familiar morphological templates filed away in the dark recesses of my memory. Then it hit me! Although the overall proportions of the beastie seemed diminutive in comparison to the model held in my head, its overall appearance reminded me of something from my adolescence back in the late 1980s – it reminded me of a mullet!

For those with a functional fashion sense (or a selective memory), Wikipedia defines a “mullet” as a “hairstyle that is short at the front and sides, and long in the back. Often ridiculed as a lowbrow and unappealing hairstyle, the mullet began to appear in popular media in the 1960s and 1970s but did not become generally well-known until the early 1980s.”

The tiny creature (which fortunately turned-out to be a caterpillar, not an outdated and free-living hairstyle) looked exactly like a mouse-sized mullet! In fact, it looked like a miniaturized version of the very mullet sported by David Bowie just a few decades ago.

Check it out:


As evidenced by the images shown above, both Bowie and the caterpillar exhibited a conspicuous, yet strangely similar, appearance. It’s this conspicuous appearance that brings us to Alfred Wallace; because, Wallace knew a thing or two about conspicuous caterpillars.

In 1889 Alfred Wallace published a book titled, “Darwinism: an Exposition of the Theory of Natural Selection with Some of its Applications.” In this work, Wallace expanded on one of his theories - a theory that he had previously presented to Charles Darwin and to members of the Entomological Society of London - the evolutionary phenomena now known as ‘aposematism.’

Aposematism refers to signaling adaptations exhibited by prey species that serve to dissuade would be predators from attacking. In other words, aposematic species are those organisms that intimidate, scare, or warn predators of their ‘unprofitability’ as potential prey items. Aposematic species are considered ‘unprofitable’ because in addition to the signaling adaptation, they also bear an underlying secondary defensive mechanism. For example, a coral snake could be considered an aposematic species because in addition to its secondary defense mechanism (a venomous bite), it also warns predators of this lethal capacity through the use of visual cues; in this case, warning coloration via strongly contrasting yellow, red and black colored bands along the length of its body.

Speaking to warning displays, Wallace wrote, “…instead of serving to conceal the animals that posses them or as recognition marks to their associates, they are developed for the express purpose of rendering the species conspicuous. The reason of this is that the animals in question are either possessors of some deadly weapons, as stings or poison fangs, or they are uneatable, and are thus so disagreeable to the usual enemies of their kind that they are never attacked when their peculiar powers or properties are known.” (Chapter IX of Alfred Wallace’s 1889 book; my emphasis added)

As an alternative to Wallace’s quoted learned avoidance of prey due to ‘known’ risks (learned through prior bad/unprofitable encounters), predators could also facilitate the evolution of conspicuous prey by practicing dietary conservatism. By simply avoiding prey items that look weird or unusual, predators could thin populations of normal looking individuals, thereby contributing to a reproductive boom for the remaining strange-looking conspecifics. In the case of a predator of caterpillars, for example, by eating ‘normal’ hairless caterpillars a predator could open the door for a surge in ‘strange-looking’ caterpillars - like those caterpillars that flaunt mullets.

In fact, Wallace frequently used conspicuous caterpillars as examples in explaining the phenomena of warning signaling - caterpillars not dissimilar to the venomous Megalopyge opercularis found on the frame of my door yesterday morning.

Megalopyge opercularis, the asp caterpillar, is the larval form of the southern flannel mouth. Its range extends from the southern United States through tropical South America. Though its retro hairstyle may look cute and harmless, it packs a painful punch. The ‘hairs’ of the asp moth aren’t really even hairs at all; they’re actually bundles of venom injecting spikes! The spikes are the caterpillar’s secondary defensive mechanism, and its conspicuousness serves as its primary defense – it sends a warning signal to predators.

Looking strange can sometimes be advantageous - just ask David Bowie!




Wallace, A. R. 1889. Darwinism: an Exposition of the Theory of Natural Selection with Some of its Applications. London: MacMillan.

Lee, et al. (2010). Can dietary conservatism explain the primary evolution of aposematism? Animal Behaviour, 79 (1), 63-74 DOI: 10.1016/j.anbehav.2009.10.004

Field Photos: White-eyed Vireo in Nest

Vireo griseus the white-eyed vireo; nested in a forked branch of Myrica cerifera (wax myrtle).

Snapshot taken a couple months back in Manatee County, Florida – where vireos nest year around.

Field Photos: Jewel Beetle Vs Yellow-eyed Grass

A jewel beetle [Buprestis rufipes (?)] having a go at the wetland plant Xyris caroliniana.

Xyris caroliniana is a species of “yellow-eyed grass” belonging to the Xyridaceae Family of monocots. It’s an herbaceous perennial common to Florida’s marshes, hydric pine flatwoods, and wetland ecotones. They display a compact erect stem and ascending leaves. Its flowers are short lived with three yellow petals.

The iridescence shown by Buprestis rufipes isn’t due to pigmentation in the exoskeleton, but rather microscopic textures in its cuticle which reflect and scatter particular frequencies of light.

These photos were taken near Goethe State Forest back in April.

Field Photos: An Endangered Fern

Below are a few snapshots of an endangered “hand fern” - Ophioglossum palmatum.

Members of the Ophioglossum palmatum are epiphytic ferns that take root in the humus that collects between the fronds and the trunks of palm trees.

These snapshots were taken last month during fieldwork near the Fakahatchee Preserve in south Florida.

Although, they’re listed by the State of Florida as an endangered species, the hand fern can also be found in Southeast Asia, South America and Madagascar.

A close-up showing the spore-bearing

sporangial spikes

Here are a few more specimens – these ones guarded by Toxicodendron radicans (Poison Ivy)

A Motivating Herd of Squirrel Frogs

I’ve really neglected this blog the last few months… There’s really no excuse for the lack of posts; I’ve just been tied-up with work, extra work (thanks for nothing BP) and personal commitments. In an effort to get things rolling again, I thought that posting a couple of snapshots would be a good idea. Small steps…

Despite a recent malaise brought about by incidents in the Gulf of Mexico, I was briefly inspired this weekend when I discovered a couple hundred juvenile frogs in my backyard. Yeah, a COUPLE HUNDRED!

Though, I’m not exactly certain where the deed went down (no ponds or puddles around), my best guess is that about 45-days ago (tadpole-to-froglet growth time) a couple (perhaps a few) of the squirrel frogs that reside in the rafters of my porch got “frisky” (i.e. mated). The result: hundreds of these guys in my yard:

Squirrel frogs (Hyla squirella) are common throughout the Southeastern United States. They’re terrestrial tree frogs that breed and undergo early development in water (puddles, ponds, ditches, etc…). Once sufficiently mature to undertake travel, they move to forested areas (or the exteriors of human dwellings) to live as adults. Eventually, the upland dwelling adult frogs return to water to reproduce and the cycle starts anew.

As another quick natural history note, Hyla squirella are at least bimodel when it comes to sexual selection. Like many frog species, the females home-in on distant males by converging on the sound of the male’s song; but, in addition to sound, female squirrel frogs also select mates based on appearance.

Squirrel frog in rafters of porch

Males with low-frequency and energetic calls are preferred by the females, but the females also consider the size of the yellow stripe that runs down the male’s side. The male’s yellow stripe may give some indication as to his overall health.

Convergent Evolution and Intelligence

Measuring only about one-tenth of a millimeter in length, the female members of the wasp species Dicopomorpha echmepterygis are likely candidates for being the world’s smallest flying animal. Though accomplished fliers, these tiny parasitoid wasps are so minute that one could sit comfortably within the circumference of the period found at the end this sentence. Equally as versed in flight, but dramatically less petite than the insect aviators, were huge pterosaurs like Quetzalcoatlus. Though no human has ever laid eyes on a living specimen, fossil evidence clearly shows that some of these masters of the sky boasted wingspans well in access of thirty feet. In addition to the huge variety of aeronautically inclined insects and reptiles that have been identified, mammals too have converged on the adaptation of winged locomotion; mammals of the order Chiroptera have taken to the sky as moth hunting bats.

Like the adaptation of flight, eyes too have independently evolved in a number of different animal taxa. From the photoreceptive eyespots of a flatworm to the sharply focusing lenses of a great horned owl, eyes have arisen at least forty different times during the Earth’s biological history. ‘Convergent evolution’ is the phrase science uses to describe the common adaptations shared between different lineages of animals. For example, a case for convergent evolution could be made for the possum’s opposable thumb, which may very well represent an adaptation for improved grip; but, this enhanced grasping ability is hardly an indicator of a hereditary tie to primates. Rather than having been passed through genetic transmission from parent to offspring, the opposable thumb simply has an analogous structure and function for both possums and primates. So, just as flight isn’t unique to birds, the opposable thumb isn’t unique to primates.

If not opposable thumbs, is there a trait that is unique to primates? More to the point, is there a trait that is unique to the variety of apes called Homo sapiens? Perhaps intelligence is unique?

Maybe not as unique as we’d like to think:
de Waal, F., & Ferrari, P. (2010). Towards a bottom-up perspective on animal and human cognition Trends in Cognitive Sciences, 14 (5), 201-207 DOI: 10.1016/j.tics.2010.03.003

Tsunamis Hit Florida - Not!

I’ve been told that there is a rumor going around about methane gas bubbles causing a tsunami...


From Florida Department of Environmental Protection:

“Tsunamis are unlikely to occur as a result of the Deepwater Horizon incident. These rumors involve the naturally occurring methane beneath the seafloor in the Macondo Discovery, which is the petroleum reservoir into which the Deepwater Horizon production well was drilled. Scientists and engineers are aware of the physical and chemical behavior of methane in the earth and ocean, as well as during production of petroleum.

Science does not support the notion of a methane-induced tsunami resulting from Deepwater Horizon activities. However, while the possibility of an induced tsunami is extremely remote, DEP continues to take all concerns seriously and is consulting with experts in all related scientific fields.

View the following DEP fact sheet with more information about methane gas and the Deepwater Horizon incident: http://www.dep.state.fl.us/deepwaterhorizon/files/methane_fact_sheet.pdf

Cottonmouth Moccasins: Adapting to the Beach and Beyond

Could some pit vipers evolve the capacity to invade the world’s oceans?


Last Thursday, while doing some fieldwork in Levy County, I came across this Florida cottonmouth as it was sunning itself after an early morning swim:

The warning behavior being demonstrated in the last photo is how the ‘cottonmouth’ earned its common name; trespassers and would be predators can be caught off-guard and intimidated when the snake curtly flashes the white interior of its mouth. The warning was certainly well received by me – I’ll take being startled over enduring a venomous bite any day of the week!

The Florida cottonmouth Agkistrodon piscivorus conanti is one of three subspecies of water moccasin native to the United States; the other two varieties include the Eastern cottonmouth (Agkistrodon piscivorus piscivorus) and the Western cottonmouth (Agkistrodon piscivorus leucostoma). These three subspecies of semi-aquatic pit vipers are renowned for their exceptional swimming ability and their associated preference for habitats in and around the freshwater lakes, streams and swamps of the Southeast U.S. They have adapted to be masters of wetlands; well, masters of freshwater wetlands anyway…

Even though their preferred range places them in proximity to the Atlantic Ocean and the Gulf of Mexico, the conquest of marine ecosystems by the cottonmouths has been - as it has with most aquatically inclined reptiles - blockaded. The physiological demands of maintaining adequate hydration in a high-saline environment has constrained the Agkistrodon genus to a landward life. But things could change.

Could cottonmouths evolve to live in the sea, like kraits or sea snakes?

As mentioned previously, the above images show a cottonmouth from Levy County, Florida. Levy County is located in West Central Florida and boasts an impressive coastline along the Gulf of Mexico. The coastline even has barrier islands. In fact, one such barrier island, called Seahorse Key, has its very own population of cottonmouths - cottonmouths that have found a niche in the intertidal zone.

Generally considered opportunistic carnivores, the bulk of the average cottonmouth’s diet is derived through consumption of its wetland neighbors - frogs and fish - however, they have been known to occasionally snack on insects, lizards, birds, rats, or even other moccasins. The cottonmouths of Seahorse Key have taken their tastes for fish from the freshwater to the saltwater; there they eat marine fish scavenged from the intertidal zone or haphazardly dropped from the Key’s bird rookeries. In addition to marine fish, the cottonmouths of Seahorse Key will even eat SEAWEED if it has the odor of fish on its leaves.

So, the cottonmouths of Seahorse Key have a proven ability to eat, digest and process marine food resources. They posses elongate lungs to provide buoyancy and streamlined bodies capable of eel-like swimming locomotion. As with other pit vipers they have venom to aid in capture of fast moving fish. And, in regards to reproduction, cottonmouths give birth to live young, so there’s no need to go to shore to lay eggs…

It seems that the only other major factor restricting the cottonmouths’ sea-ward invasion is a limited tolerance for high-salinity…

If only there was a selective pressure for improved salt water tolerance; for instance, a selective pressure something like being stuck on an island that is subject to rising sea levels. What are the chances of that happening?

The behavioral and physiological adaptations required in order for a land animal to successfully undertake a conquest of the sea are undoubtedly both varied and numerous; but, with sufficient selection pressure, ample time, and an incremental, step-wise process it can and has happened.

For example, consider all of the behavioral and physiological changes that must have occurred in order for a few Devonian lobe-finned fish to find their way to shore as fully terrestrial tetrapods! Or, viewing the scenario in reverse, imagine the adaptations that permitted Eocene land mammals to re-enter the sea as a line of cetaceans!

Subtle cumulative changes over time can alter a lineage’s dietary preferences, reproductive rituals and even bodily mechanics.

Lillywhite, H., Sheehy, C., & Zaidan, F. (2008). Pitviper Scavenging at the Intertidal Zone: An Evolutionary Scenario for Invasion of the Sea BioScience, 58 (10) DOI: 10.1641/B581008

What Spider is this?

Anyone know which species of spider this is?

It was in west central Florida - near Crystal River, Levy County.

I'm guessing Gea heptagon, but haven't seen one quite like this one - with so many numerous huge spines...

Awesome Picture: Florida Panthers in the Picayune

I was just emailed this picture of a mama panther and her cubs:

The email (from a reliable source) advises that the photo was recently taken during a fly-over of the Picayune Strand near Naples in South Florida.

Looks like three wild Florida panthers - cool!

Also pictured are what looks like a recently cleared road and stands of noxious Melaleuca – could be better! (As a matter of fact it is getting better - click here for info).

In addition to dealing with us ecosystem-altering and land-lusting apes, Florida panthers must also cope with other parasites – including highly specialized trematodes that have evolved a fancy for fare of the feline sort...

Trematodes are flukes of nature (sorry, couldn’t resist) in that they've evolved an astonishing, almost incomprehensible level of developmental plasticity. Most have evolved the ability to subtly manipulate their growth rates and sexual maturation to track the resources available in their environment. For parasitic nematodes, their environment is manifested by the internal chemistry of their victims. Id est, the digestive enzymes, hormones and antibodies expressed through the physiology of their hosts help the trematodes gauge the probability of reproductive success and to tune their own developmental process accordingly. This fantastic capacity for flexibility is of survival benefit because should a trematode happen to find itself immersed in the body of an unsuitable host, it can induce a state of arrested development and shift its metabolism to complete dormancy while awaiting transmission to a more favorable chemical climate. As a natural corollary, if the trematode succeeds in locating its target host (aka, its 'definitive host') it can quickly push development into overdrive and achieve reproductive adulthood in short order, thereby maximizing the opportunity to its individual advantage. Being unrestrained by the ticking-clock of reproductive efficacy, trematodes can migrate from host-to-host and even between species with relative ease. As a case study, consider the misadventures undertaken by the trematode species named Alaria marcianae.


Alaria marcianae is a fascinating organism known to target, as definitive hosts, the kittens of the Florida Panther (Puma concolor couguar). The Florida Panther holds a critically endangered status and, as the common name strongly suggests, resides in the state of Florida. The tawny colored Florida Panther is one variety of a widely recognized group of felids that are also known by the names cougar, mountain lion and puma. The panther-intersecting life cycle of Alaria marcianae is complex with several possible vectors of transmission, but in choosing an arbitrary starting point for the purpose of description, we can assume that its convoluted journey begins within the intestines of an adult panther.

Having recently been deposited in the intestinal tract of an adult feline, members of Alaria marcianae start their lifecycle as eggs. The eggs, unembryonated germ cells, intermix with the partially digested remnants of raccoons, armadillos and other common delicacies found in the panther's system, and are then excreted with the animal's feces. On being submerged in the inundated wetlands for which south Florida – and the Picayune Strand - is renowned, water stimulates the eggs to internally develop embryos. Once these embryos have achieved sufficient maturation, sunlight triggers the eggs to hatch free swimming, cilia-driven, paramecium-looking critters called miracidia.

The miracidia are not adult Alaria marcianae, rather they represent a sexually immature stage of development that is specialized for seeking out a very specific (obligate) intermediate host. To ultimately succeed in stalking a panther, the miracidia of Alaria marcianae must first locate and infect a ram's horn snail of the genus Helisoma.

On locating a ram's horn, the miracidium attaches itself to the soft exposed flesh of the snail, and by excreting tissue-degrading enzymes, it parts ways with its cilia-bearing outer layer. It then penetrates into the snail's body cavity. Shedding its ciliated epithelium, the miracidium becomes an immature sporocyst. Although sporocysts still lack the ability to reproduce sexually, by embedding in the snail's nutrient rich organs they acquire the power to produce additional replicates of themselves - clones called 'daughter sporocysts.'


Further advancing on the panther, the new daughters promptly leave their mother's side and venture to the snail's gonads. Mollusk hormones produced by the gonads fuel special cells within the daughters as they morph into tailed, tadpole-looking larval forms called cercariae. The cercariae swim to, and exit from, the snail's shell-producing mantle. From there, they return once again to the open water as free-swimmers.

Leaving the snail behind, the cercariae swim to the water's surface and hunt down the true tadpoles of the leopard frog (Rana pipiens) - their second intermediate host. Hijacking the leopard frog's tadpoles for transport, the cercariae drop their own tail and burrow into the tadpole's skin. There's no need for self-propulsion when riding inside a tadpole. Once inside the developing frog, Alaria marcianae, then at a stage where they're referred to as mesocercaria, cease further development and undergo another round of asexual cloning. As numbers continue to multiply, they patiently rest, waiting for the tadpoles to carry them landward as adult leopard frogs.

In time, the mesocercaria-bearing tadpoles grow into leopard frogs and move their parasitic cargo to land. On terra firma the leopard frogs are hunted by a wide range of predators; occasionally falling prey to yet another preferred host (aka, a 'paratenic host') of Alaria marcianae, the raccoon. After catching an infested frog, the raccoon's digestive enzymes make short work of the frog's flesh - in the process releasing the mesocercaria. As with its previous host, the mesocercaria multiply in the raccoon, but continue to maintain a state of arrested development - they are not yet adults.

Did I mention that raccoons in south Florida happen to be a favorite prey item of the endangered panther?

Utilizing methods similar to those during the frog-to-raccoon transmission, Alaria marcianae find their way into adult panthers by contaminating raccoons - panther prey. During the process of raccoon digestion, mesocercaria are liberated from tissue and enter the bloodstream by penetrating the intestinal wall.

Now, if the panther they find themselves parasitizing, by chance, turns out to be a lactating female, her hormones will stir the mesocercaria into migrating to her mammary glands where they will transmit (trans-mammary) to the digestive system of her kittens'. The term used to describe the situation in which a mother acts as a paratenic host to her own offspring is called 'amphiparatenesis.'

Here, amphiparatenesis results in the imbibing of mesocercaria-laden milk by the kittens. As with the mesocercaria residing within their mother, the parasites in the kittens will penetrate the intestinal wall and enter the blood stream. They'll surf the blood stream until reaching the lungs where they become metacercaria; as metacercaria they harden the surrounding lung tissue forming protective cysts. Having profitably acquired housing in their definitive host, the cysts in the lungs will eventually be coughed-up the trachea and then promptly swallowed into the esophagus. Once back in the intestines, Alaria marcianae accelerates its developmental process, achieves sexually reproductive adulthood (as sequential hermaphrodites), and deposits the next generation of eggs in the intestine.

Thus the cycle comes full circle.




Reference:
Foster, G., Kinsella, J., Sheppard, B., & Cunningham, M. (2009). Transmammary Infection of Free-Ranging Florida Panther Neonates by Alaria marcianae (Trematoda: Diplostomatidae) Journal of Parasitology, 95 (1), 238-239 DOI: 10.1645/GE-1749.1

Douglas Adams on Lemurs, Dolphins and other Wildlife

Cool just found this at TED - funny!

It's From back in 2001.

Douglas Adams' close encounters with these rare and unusual animals reveal that evolution, ever ingenious, can be fickle too -- in a University of California talk that sparkles with his trademark satiric wit.