Fact of the Day .CA

Now that the weather is getting warmer and life is emerging from the cold of winter you may notice swarms of bugs that seemed to appear out of no where.  As requested I will focus on midge flies.  These little buggers show up around late March to April depending on the weather.  They can appear in large swarms in Southern Canada around the Great Lakes and the Northern States of America.  This is especially true if you live near a body of water because the flies require water for their life cycle.  They lay their eggs in or near the water and when the larvae emerge from the eggs they remain in the water until they transform into their adult stage, which is the flying stage.

When the weather is just right the larvae will transform into their adult form.  Now these poor buggers don’t have much time to make the next generation.  So they head off and mate in swarms.

Although bugs have always been a nuisance to us humans they are important for the ecosystem.  Midge fly larvae are food to some fish and I’m sure the spiders don’t mind the adults either.  So patch up your screens, drain the pool, and avoid turning on lights at night to prevent these critters from living in your home.

Sources:
http://lancaster.unl.edu/enviro/pest/factsheets/262-95.htm
http://www.thestar.com/news/gta/article/638591
http://www.thecanadianencyclopedia.com/index.cfm?PgNm=TCE&Params=A1ARTA0005278

Researchers have successfully found a way to restore red-green vision to colour blind adult Spider Monkeys.  The monkeys were trained to touch coloured dots with their head on a touch screen.  The screen was filled with grey dots of varying sizes and a select cluster of the dots were coloured; the select cluster of dots varied for each session.  This was similar to the images used to determine colour blindness in humans: a circle of dots with select dots being coloured differently to creat the shape of numbers (see one here).  When done correctly the monkeys were given grape juice as a reward.  Some of the monkeys had normal colour vision while others had colour blindness.  The colour blind monkeys were unable to detect the red or green coloured dots among the grey ones.  They were not rewarded on these occasions and were said to have gotten frustrated and would even shake the screen.  Two of the monkeys with colour blindness were given gene therapy via an altered virus injected behind the retina of the eye.  The gene that the virus inserted was that for the red pigments found in cone cells (which detect colour) of the eye.  After 20 weeks the two monkeys were capable of seeing red and green; as was shown by their increased ability to correctly identify the coloured dots.  This could have great implications for humans; colour blindness is the most common genetic disorder for humans.  It is also interesting because it has been believed that the adult human brain is unable to undergo new changes.  This study showed that adult monkeys were able to take in the new gene to alter the activation of cone cells in the eye, suggesting that the brain is capable of making alterations during adulthood.

Sources:

http://news.nationalgeographic.com/news/2009/09/090916-color-blind-gene-monkeys.html

http://www.nature.com/news/2009/090916/full/news.2009.921.html

Albinism is found in a wide variety of species from plants to animals to humans.  It is a recessive gene that causes the production of the pigment melanin to be below normal levels.  This can leave the skin, hair, and/or eyes with a different colour, usually a shade between white and pink, depending on its severity.  White tigers are an example of albinism; zoos use special breeding programs in order to retain this effect.  Due to lacking pigment in the skin albinism leaves skin vulnerable to the Sun’s UV rays,  resulting in faster and more frequent cases of sunburn and a higher risk of skin cancer.  The lack of pigment in the iris of the eye can damage the retina due to a larger amount of light entering the eye.  Albino animals that have small eyes, such as mice and rats, appear to have red eyes because the blood vessels of the retina are visible through the clear iris.  Red eyes are rare in larger animals such as humans; the iris is usually a pale blue but some cases have been reported as red or purple.  There appear to be no other physical disadvantages for albinos, other than the incapability of animals to camouflage which decreases their chances of survival.

Cetacea is the Latin order for whales, dolphins, and porpoises.  The WDSC North America states that there are 20 species recorded to have cases of albino individuals.  Some of these species include Sperm Whales, Pilot Whales, Humpback Whales, and Bottlenose Dolphins.  In 1982 there was a  paper published in the Journal of Mammalogy stating that there had been two albino Pilot Whale sightings in 1976 and 1980 at 215 km SE beyond the continental shelf edge of Halifax, Nova Scotia and 211 km SE beyond the continental shelf edge of Nantucket Island, Massachusetts respectively.  It is unknown whether these two sightings were of the same animal or two separate animals.  The paper suggests that the disadvantages of albinism in cetaceans would be their inability to blend in with the rest of the pod (for social species) or with their environment.  Sunburns are less of a problem for cetaceans because they spend the majority of their life under the water.  Being a different colour than the rest of the animals in the species causes the albino to be susceptible to predation and extra human attention.  Additionally it may decrease their reproductive success because in the animal kingdom differences in colour can be a health indicator and a difference in colour could deter mates.

Albino cetaceans are not to be confused with species that are naturally white or light in colour.  One such species is the Beluga Whale, also known as the White Whale.  These animals are born a pale brown-grey colour; their pigmentation darkens in approximately the first 6 to 7 years of their life.  They then begin to lighten up and at around 10 to 12 years of age they are almost white.  They continue to become more vibrantly white as they age.  These animals can be found in the Arctic and the St. Lawrence River of Quebec.

Another cetacean which has different pigments but is not albino is the Amazon River Dolphin or Boto (Inia geoffrensis) which has been called the pink dolphin.  It is thought that the pink markings in this species are scars that result from male aggressive interactions.  This is thought because the pink colour is mostly found on males  that have shown aggressive behaviours amongst each other.

Next time you find yourself in a dicussion about the book Moby Dick, which is about a white whale, be sure to mention that he is an albino cetacean (sperm whales are normally black).  Your friends will be wildly impressed, I guarantee.

Special Thanks:
Whitehead Lab at Dalhousie

Tardigrades, commonly known as ‘water bears’, are capable of surviving many extreme habitats (polyextremophiles).  These tiny animals (0.1mm-1.5mm) are mostly found in moist environments but have been found to withstand a range of temperatures (151C to -272C), pressures (low pressures of a vacuum and more than 1200x atmospheric pressure), dehydration, and radiation that would kill most animals (5000Gy gamma-rays and 6200Gy heavy-ions).  When the living conditions of the environment decrease the animal will resort to a state called ‘cryptobiosis’.  While in this state the animal’s metabolism can reduce to 0.01% of its normal rate and their water content can be reduced to 1% of the normal water content.  Tardigrades can remain in a cryptobiotic state for up to 10 years.  When environmental conditions improve the tardigrade will return to a normal living state.

Scientists put these animals to the test (see study here); two species of tardigrades were sent into space in this cryptobiotic state on a low orbiting satellite around the Earth (258-281km above sea level) for 10 days.  Both of the species used in this study successfully survived the exposure to the vacuum of space.  Two thirds survived additional exposure to the UVA and UVB radiation levels found in space.  Very few tardigrades survived the additional exposure of all UV radiation found in space, which is usually filtered out by the atmosphere.  Those that survived the trip into space and survived rehydration were capable of producing offspring!

No one is sure of why or how these animals are capable of surviving so many different extreme environments.  Are they just over evolved?  Or was it a response to a selective pressure of the past?  Whatever the answer these unusual animals need further study as humans prepare to face the extreme environments of our Solar System.

In 2007 a group of researchers published a study of ground squirrels and rock squirrels that found the rodents are doing something very interesting: the squirrels chew up discarded rattlesnake skin and then lick their tail and flanks. This transfers the skin chemicals to the squirrel’s fur and makes them smell like snakes. Several theories were proposed. Perhaps the squirrel was trying to smell like a snake to scare away competitor squirrels. Or maybe it was used to confuse fleas and other parasites. Or perhaps the squirrels wanted to smell like rattlesnakes to ward off other rattlesnakes. The scientists took videos of the grooming behavior in 46 ground and rock squirrels. They concluded that because females and juvenile squirrels were much more thorough with their snake scent application it was primarily an antipredator defense, because these groups are much more vulnerable to rattlesnake predation.