Dinocampus coccinellae

Originally published in The Manitoban, 2011

Ah, time to go back to school. If you're anything like me you've probably bought a bunch of new pens and stationary you don't really need and have resolved to read your textbooks and class notes every day, maybe even get up extra early before classes to do something physically healthy. Soon enough though, as the first 2011 semester kicks into high gear, most of us are bound to feel as exhausted as though the life were being sucked right out of us. That's why I have chosen to begin the first fall issue of The Manitoban by telling you about the parasitic wasp Dinocampus coccinellae.

D. coccinellae is found throughout Eurasia and North America and parasitizes numerous species of lady beetles (your friendly, aphid-eating, garden variety “lady bug”). Females mate with males as infrequently as possible. A queen will store the sperm from a single mating for up to one year, using this sperm to fertilize eggs and produce sterile female workers which she uses to build her colony. When the sperm begins to run out, fertile males and females are produced and these disperse to form new colonies. 

Thus, males are rarer than females, although they are produced every once in awhile so they can disperse, mate, and contribute to the genetic diversity of the species via sexual reproduction.

The wasps preferentially parasitize female lady beetles and do so by injecting an egg directly into the beetle's body cavity. Once the egg hatches, the larva eats the lady beetle's own eggs in order to nourish itself and eliminate competition for nutrients. Once the eggs have all been eaten, the larva begins to eat it's lady beetle host's surrounding body tissue, including her reproductive structures.

After about 20 days the larva is ready to emerge. This is achieved by chewing a hole through the lady beetle's body. Then, the larva is ready to spin a coccoon inside which it will metamorphose into an adult wasp. The larva spins its coccoon within the hind limbs of the lady beetle, who is paralyzed, still alive and probably very miserable.

Currently unidentified venoms secreted by the wasp larva are believed to be responsible for the next stage in this ghastly business. The lady beetle, paralyzed with a wasp coccoon under her body, is now also a victim of behavioural modification courtesy of the wasp—the beetle begins to twitch and grasp erratically. This behaviour, along with the familiar red and black colouration of the lady beetle, serves to ward off predators, thus protecting the developing larva.

Many species of parasitic wasps lay eggs in a variety of host species; however, most of these lead to the death of the host. Not so with D. coccinellae, although I bet the lady beetles wish they were dead. After the adult wasp emerges from its coccoon, the effects of paralysis wear off, as does the behavioural control exerted by the larva. Approximately 25% of parasitized lady beetles survive this process and presumably amble off to continue their regular lady beetle duties, albeit with gored reproductive organs and a pretty wicked hole in the undercarriage.

Yet leaving the host alive is not without costs of its own. After all, nothing in life is truly free, right? Researchers at Laboratoire Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle (CNRS/IRD/Université Montpellier) and the Université de Montréal were able to show that while wasp larvae guarded by lady beetles are less likely to experience predation, they also lay fewer eggs (Maure et al. 2011). The developing larvae lose resources by keeping the lady beetle alive, resulting in the observed reduction in fecundity of the adult wasps. Maure et al. (2011) showed that while larvae without lady beetle protection are more likely to experience predation, those that survive lay more eggs on average than wasps with a lady beetle bodyguard.

So when the term hits full swing remember—you don't have it half as bad as the spotted lady beetle does!

African Crested Rat

Originally published in The Manitoban August 17, 2011

I hereby nominate the African crested rat, Lophiomys imhausi, for entry into the Baddest-Ass Mammals In the World Hall of Fame. 

Here's why: when these reckless rodents are faced with a ravenous predator ready to rip them to shreds for breakfast they don't even care. They just stand there daring anyone to mess with them. And for good reason—you totally might die if you try eating a crested rat. They are really poisonous!

Crested rats actively seek out Acokanthera schimperi trees, the so-called poison arrow trees traditionally used by certain African tribes for lacing spears and arrows with deadly, elephant-killing poison. The rats chew the bark of the poison arrow tree and lather the poison-rich spit over a specific region of their body. This organic poison contains a compound called ouabain, which inhibits the sodium/potassium pumps embedded in the cell's plasma membrane. 

The sodium pump maintains the electric resting potential of a cell and is essential to normal physiological function. Ouabain is a cardiac glycoside, increasing the force of heart contractions and cardiac output. Left unchecked, ouabain causes death by heart attack.

It is not yet known how the African crested rat is itself able to resist the normally deadly effects of the poison it has usurped for its own defensive purposes. The rats have enlarged salivary glands and stomachs, which may help to process, dilute and detoxify the poison. 

In the medical world, ouabain has been used in small doses to stimulate weak hearts to contract and beat more strongly. Ongoing research exploring the resistance of the rats to A. schimperi's toxic effects may someday be used to treat humans suffering from heart-related illnesses and to better understand the effects and potential uses of other cardiac glycosides.

The African crested rat, native to northeastern Africa, is the only known mammal on earth which actively seeks out and acquires toxins from a plant for use in its own physical defense. Further, the crested rat advertises its borrowed toxicity by performing a specialized display behaviour when confronted by potential predators.

When exposed to a threat, the rat will hold its ground and expose specialized hairs along its flanks by parting the grey fur that normally covers all of its body, revealing a patch of hairs surrounded by strikingly black and white striped fur. These specialized hairs are highly modified and unique to the African crested rat. 

When viewed under a microscope, it can be seen that the hair shafts contain numerous perforations throughout their length, creating a wicking effect which draws the toxin into and along the full length of the hairs. This allows for maximum retention of the deadly poison-laden spit the crested rats coat these hairs with after chewing the poison arrow tree bark. No other animal is believed to possess hairs of this type.

Other taxa, both vertebrate and invertebrate, have shown comparable poison-stealing behaviours. Some sea slugs steal the poisonous stinging cells of cnidarians, which I wrote about in an article on nudibranchs back in August 2009, for example, but this is the first documented instance of a toxic poison theft in a placental (eutherian) mammal. The only other mammal known to perform a similar behaviour is the hedgehog, which applies toxins from the poison glands of certain toads to its quills; however, this merely causes pain and irritation for potential predators, a long way short of the heart-stopping death which can ensue from messing with the African crested rat!

Hercules Beetle

Originally published in The Manitoban, November 10, 2010.

Love 'em or hate 'em, insects are arguably the most important animals on earth. They are often viewed as the most successful animals on the planet. Many insects are essential for the continuation of life on earth as we know it due to their roles as plant pollinators and degraders of waste products left by other organisms, which prevents massive build-up of organic wastes that would otherwise bury the planet in filth. In fact, about two-thirds of all flowering plants are pollinated by insects. 

Insects are also among the most important carriers of and vectors for diseases that kill millions of humans and other economically important mammals annually. Insects are frequently used as models in scientific research—due to their (often) small size and rapid generation times, many can be bred quickly and in large numbers in laboratories for experimentation in various areas, including genetics and medicine. 

Insects have been around for a long time, too—at least 400 million years. For comparison, the first mammals appeared roughly 225 million years ago. Man are there lots of insects! Estimates vary, but it is thought that there are anywhere from six to ten million living species of insects alive today, and these species are grouped into 29 different orders.

Beetles make up the order Coleoptera which, I don't mind telling you, with over 360, 000 described species, is the largest order of insects in the world. In fact, at least 25% of all species rambling about the planet today are beetles. How will you know if you are looking at one of these wonderful, wildly abundant beetles or just some other type of insect, you might want to know? 

Beetles are perhaps most easily recognized by their two sets of wings. One set is the kind of wing you think of when you imagine insects flying (I'm sure you imagine insects flying quite often), while the other set of wings, called elytra, are hardened into a protective, leathery sort of cover that protects the more delicate wings underneath, and may also act as aerofoils. 

The order Coleoptera is amazingly diverse and contains both the largest and some of the smallest insects on the planet today. It is about one of the largest living insects that you, the enthralled reader, are going to learn—the Hercules beetle.

The Hercules beetle, Dynastes hercules, is a type of rhinoceros beetle (subfamily Dynastinae) and is a member of the family Scarabaeidae, the scarab beetles. These Hercs, as I'll call them, are native to South and Central American rainforests and the Lesser Antilles. They range from 50 to 170mm (over 6 inches) in body length—making them one of the world's largest beetles1 and the largest of the six beetles in the genus Dynastes. As if their size weren't impressive enough, male Hercs have two big horns that can be even longer than their body; one that comes from the lower (ventral) portion of the head, curving upward, and another that comes from the thorax at the base of the upper (dorsal) region of the head curving downward, like a pair of pincers or pliers. When males fight, they try to pick one another up with their horns and slam them headfirst to the ground. Females lack horns.

Hercules beetles are not poisonous and they do not attack humans. They mostly just hang out in leaf litter trying to survive the decimation of the rainforest while still managing to look really cool and menacing. They are herbivorous, the larvae eat rotting wood and dung while adults feed on decaying fruit and vegetable matter. Again, just cleaning up the garbage. Really, they are humble civil servants of the rainforest, never complaining about their smelly job or asking for recognition, even though they deserve it.

Hercs can live for about 1.5 years, only 3 to 4 months of which are spent as adults. They are primarily nocturnal and are strongly attracted to light.

My favourite thing about Hercs is that if you correct for size, Hercules beetles are, proportionally, the strongest animals on the planet. They are able to lift up to 850 times their own body weight!

1. The record for world's largest beetle is held by the aptly named Titan beetle, Titanus giganteus, which is a member of the family cerambycidae or longhorn beetles, and reaches 170-175mm in length.

please ignore the pin

 

Water Boatman

Originally published in The Manitoban summer ?? 2011.

Ah – summer in Winnipeg; muggy heat we can't stand after 8 months of zero humidity and freakishly cold winter, freak storms, flooding, mosquitoess, canker worms, E. coli-infested eutrophic lakes – we love it all and by George we'll take it! This sweltering mid-summer issue I would like to tell you about a really cool bug. A bug you can respect: the Water Boatman.

The Water boatman belongs to the insect order Hemiptera, the true bugs (a cold virus is not a bug, a bacterial infection is not a bug, a fly is not a bug). Whether an insect is truly a bug depends on specific details of the wings and mouth parts, which are modified for piercing and sucking, oh my.

Water Boatmen are aquatic and have oar-shaped hind legs used for paddling. They typically inhabit lakes and ponds. These insects do not have gills and must breathe air from the water's surface; however, they frequently carry an air bubble with them during their lengthy underwater adventures and breathe oxygen from within the air bubble!

Over 500 species of water boatman have been identified, more than 100 of which are found in North America. Amazingly, one species in particular, Micronecta scholtzi, has just been credited as the loudest animal on earth! Water boatmen are only about 2.5 millimeters long and yet they create sound at volumes similar to that of a passing freight train or what you would hear sitting front row during a loud orchestra performance. This brain-boggling volume is produced during stridulation, sound produced by rubbing the differently sized ridges of two body parts together. In the case of the water boatman, stridulation is performed by rubbing the penis against the abdomen, which in a sense means the water boatman has the loudest penis in the world (hard to believe, I know).

A recent study by Sueur et al. (2011) reports a peak value of M. scholtzi calls at 100dB SPL (a log ratio between measured sound pressure level and a reference point defined by the threshold of audible hearing for humans). M. scholtzi thus has the highest ratio of dB (decibel) to body size ever recorded, making this water boatman the loudest animal on the planet!

Why do water boatmen need to be so loud? The song produced by stridulation is used to attract females. The males produce a three part song and it is the third part which is the loudest, meant to drown out the songs of competing males. Sueur et al. (2011) propose that the extreme volume achieved by M. scholtzi during stridulation may be the result of runaway sexual selection via intra-male competition.

The idea is this: females localize the acoustic signals produced by loud males more easily than those of quieter males whose songs are masked by the loudest males. Typically, there is a balance between signal volume (high volume = more females) and predation (higher volume = more predators) but in this case, it is possible that the water boatmen either have no predators that use acoustics to find prey or the boatmen are so effectively able to evade these predators that the volume of their signal is not regulated by the negative selection pressure normally imposed by predation (Sueur et al. 2011). In short, the male with the loudest penis gets the most females. 'Nuff said.

Ogopogo

Originally published in The Manitoban, March 30, 2011 (April Fool's special edition)

In British Columbia they have a lot of lakes. The one you should be most concerned with is Lake Okanagan, the home of Ogopogo. Formally recognized by a prominent B.C. scientist in 1872, Ogopogo is a charming aquatic serpent some 20 to 50 feet long and 1 to 3 feet wide with a gruesome horse-shaped head. This serpent-like animal has a long, undulating body with many large spinous processes. These might have evolved to serve as extra sites of muscle attachment for flexion of the long trunk, which would require significant strength to turn quickly in such a viscous medium as water. Ogopogo has dark brown, black, or blue skin and uses counter-shading similar to many fish and other aquatic species. Counter shading is characterized by a lighter epidermal (skin) colouration on the underside of the body and a darker pigmentation on the dorsal surface. This functions to camouflage the animal because, when viewed from above, the dark skin blends in with the dark, deeper waters and when viewed from below, the light skin blends in with the lighter colour of the shallower waters that can be penetrated by the sun’s rays.

Ogopogo is respectfully known to the Aboriginal peoples of the Okanagan area as “N’ha-a-tik”, which roughly translates to “water god” or “water demon”. Those who have encountered this fearsome and secretive animal report escaping near death by boat tippings and general goring by the sacrifice of any other animal they might have with them at the time. 

So let it be known that Ogopogo takes bribes, folks and that is definitely good news for humanity, but bad news for designer dogs going on vacation to “Beautiful British Columbia” this summer.

Ogopogo is still seen today, but less frequently than in the past. This may be due to the animal’s reported penchant for eating horses, which are no longer a popular mode of transportation and hence are less common in the Okanagan region in these technologically advanced times. Of course, environmental factors other than food availability may be playing a role in Ogopogo’s apparent decline. The ever-bearing crush of human development may be partly responsible, as well as nutrient loading and water pollution. 

While the exact reasons for Ogopogo’s decline are not yet known, this beautiful monster’s conservation status is, at least for the time being, quite certain. Ogopogo is protected under provincial legislation and has been so since 1989, “It is illegal to harm, kill, capture or disturb” Ogopogo in British Columbia.

Copyright Edward Fletcher

http://www.bcscc.ca/ogopogo.htm

(this website rules! So does the site “fuck you, penguin” check it out)

Crested Gecko

Originally published in The Manitoban, March 2, 2011

They say it is better to have loved and lost than never to have loved at all and in general, I agree. After all, Alzheimer's aside, memories are forever right? So let's let the good times roll and get on with it.

You may not know why, but that brief yet significant introduction brings me to this week's subject: the crested gecko, Rhacodactylus ciliatus. 

Crested geckos are endemic to New Caledonia, an island located just about halfway between Australia and New Zealand (Dear New Zealand, I am sorry about the earthquakes). I've talked about the unique situation islands pose for evolution and speciation before, so I'll just point out that roughly 86% of New Caledonian reptiles are not found anywhere else in the world (they are endemic).

Originally described in 1866, the crested gecko was believed extinct until it was rediscovered by science in 1994. Since that time, and due to the relative ease with which they can be bred in captivity, crested geckos have become widely popular as household pets.

Permit me, if I may, to briefly state that captive crested geckos require full spectrum UV lighting, at least 50% average humidity, and temperatures between 20 and 26°C. Their enclosures should be tall enough to permit climbing, they should have things to climb on, you cannot keep mature males together, and they do best with a variety of live invertebrates and fresh fruits supplemented with commercially available vitamins and calcium. Don't let anyone tell you any different.

There are six species in the genus Rhacodactylus, all of which are found only on the island of New Caledonia. One species, the New Caledonian giant gecko, R. trachyrhyncus, is listed as endangered by the International Union for Conservation of Nature (IUCN) and is also the largest known gecko on the planet! In gecko terms, the 34 centimetres length R. trachyrhyncus can reach, definitely warrants giant status. In contrast, R. ciliatus, the species most often sold in stores, generally reaches lengths of 10 to 26 centimetres, about half of which is tail.

Crested geckos are nocturnal, predominantly arboreal, and very cute. They can be various shades of brown, grey, and red and their colour may become more or less vibrant depending on the environmental conditions and time of day. 

Their name derives from the fact that they have lightly spiked fringes on either side of the head which run from the base of the eye, over the dorsal surface of the orbit (eye socket), and down towards the neck. This gives them the appearance of having long, flirtatious eyelashes, enhancing their popularity in the pet trade, but more importantly acting to deter potential predators.

Crested geckos do not have eyelashes. They have a thin, transparent layer of skin called a nictitating membrane which can be drawn across the eye to protect and moisten it. One of my favourite things about crested geckos is that they often just sit and lick their eyeballs, especially after eating. Their tongue is very long and soft, with a widened spatula-like tip. Nothing else that can lick its own eyeball has ever looked so endearing while doing it, let me tell you.

Unlike other lizards, crested geckos have a prehensile tail, which helps them grip branches whilst roaming about the lush rainforests of New Caledonia. In addition, their tail is flattened at the tip and equipped with minute transverse folds called lamellae. These lamellae are further divided into many tiny bristles, or setae, made of a hard organic protein called keratin. The setae get even more complex under a microscope; they are further sub-divided into minute hairs, only 200 nanometers in diameter. The broad toe pads of the crested and many other gecko species have these same features, which vastly increases their surface area and enables the gecko to climb vertical and very smooth surfaces with great skill and agility. Part of this adhesive magic involves the weak van der Waals forces you may have tried to ignore in chemistry class.

Crested geckos are currently being reviewed by the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES) for classification. Only two of the six species have so far been classified, with R. auriculatus listed as least concern R. trachyrhyncus endangered.

This article dedicated to the memory of Mr. Twist

Mr. Twist (2004 - February 16, 2011)

Cassowary

Originally published in The Manitoban, February 2, 2012

Zoological Investigations: Cassowary

The cassowary is a large flightless bird that along with ostriches, emus. kiwis, and rheas is a proud member of the ratite group. The term ratite refers to the shape of the breastbone or sternum; these birds are flightless because the sternum lacks a keel, the site for flight muscle attachment.

There are three species of cassowary: the northern cassowary, Casuarius unappendiculatus, the dwarf cassowary, C. bennetti; and the southern cassowary, C. casuarius johnsonii, (a.k.a. the double-wattled cassowary). All are found in different regions of New Guinea, but only the southern cassowary can be found in Australia. This article will focus on the southern cassowary, mostly so I can type the word 'double-wattle' a lot.

So picture an ostrich, but with shaggy-looking black feathers, a bald blue neck with bright red 'wattles' (flaps of skin) hanging off each side, and a bald, bluish coloured head with a big, brownish thing that looks like a blade-shaped crest or flattened horn on top. This thing is called a 'casque' and it is pretty awesome and mysterious.

The outer layer of the casque is made of keratin (the stuff of fingernails), while the inner portion is made of an odd, foam-like cellular material. The best guess going regarding the function of the casque is that it is used for protection. When cassowaries run through the rainforested jungle, they stretch out their necks and really give 'er. Cassowaries can reach speeds of up to 50km/hr and the resilience of the casque, along with its elastic properties, are believed to efficiently absorb the shocks of getting whipped in the head with branches and occasionally running head-long into trees.

The cassowary's feathers appear shaggy because their structure differs from that of birds capable of flight. They do not have tail feathers or the uropygial (preen) gland used by other birds to keep the feathers clean, water resistant, and their bodies well insulated. The flight feathers are reduced to only five or six elongated, quill-shaped feathers that apparently help protect the birds while they are running madly through the bushes.

The double-wattled cassowary is the second heaviest bird in the world; weighing in at up to 128 pounds, only ostriches are heavier! The double-wattle also has the honour of being the third-tallest bird in the world. Yet another impressive cassowarian feature is the double-wattle's ability to jump up to five feet high in the air. They are terrifyingly strong, with long and powerful legs equipped with huge claws up to 10 centimetres long. The cassowary is not afraid to run full tilt at a potential predator and kick and slice its body right open. There are reports that humans and dogs alike have died as a result of the double-wattle's cutting blow.

Cassowaries, like me, usually like to hang out on their own; except, like me, during the mating season. At such times, they will tolerate the company of another cassowary for awhile, at which point they do what a cassowary must to keep the species alive. This is important because cassowaries are endangered. 

The double-wattled cassowary is listed by the government of Australia as endangered under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). It was estimated in 2001 that fewer than 1500 individuals remain alive in the wild, making these guys rarer than giant pandas in China. As usual, habitat loss due to deforestation; development; and urbanization are mostly to blame. Vehicular traffic, dogs, and wild pigs are also responsible for cassowarian decline, as are humans that attempt to feed the double-wattles. A tamed double-wattle makes an easy target for cars, dogs, and pigs alike.

Female cassowaries mate with one male, lay eggs in his nest, and then leave in search of other males and other nests in which to lay their eggs. The males incubate the eggs and care for the chicks, which stay with him for between nine and 18 months.

Cassowaries are basically the coolest, and for so many reasons! In addition to being the second heaviest and third tallest bird in the world, really fast, really strong, really weird looking, great swimmers, and the possessor of a not-so common breeding system, cassowaries are also considered a keystone species. Basically, this means they play an crucial role in their ecosystem, even though they are not the most populous species within that ecosystem. Without the cassowary, many other organisms would suffer or die out completely.

Cassowaries are primarily frugivorous, which is fancy-talk for fruit-eating, and many plant species can not germinate unless they have first passed through the digestive tract of a cassowary. Their digestive tract is short, so food passes rapidly through the system, and hence ingested seeds are not destroyed. This partial digestion removes the tough, protective seed coat and speeds the process of germination of those seeds. Currently, up to 70 plant species have been identified which have seeds so large that no other animals can eat them. The cassowaries, by eating seeds from these plants, help disperse those seeds far and wide, increasing the likelihood those plants will survive and reproduce. As if that wasn't enough, another 80 plant species have been found which are toxic, and only the cassowary, with their rapid-acting digestive system, can consume them without harm. Again, this is crucial for the dispersal of these toxic plants. 

 

I bet you there are some pretty crazy videos on the internet where you can watch a double-wattled cassowary run and kick some stuff with it's huge, powerfully clawed feet. Just sayin'. 

Southern Cassowary with young.