Posts

Male moths and pheromone detection - finding females

Image
Male polyphemous moth showing its large antennae While butterflies are known for their daytime activity and slender antennae, moths are known for the polar opposite.  With broad, feathery antennae and nocternal behaviours, they stand apart from their Lepidopteran relatives.  However, another difference lies in antennae differences between males and females.  Butterflies show no significant difference, while in moths, the males' antennae are much larger than the females'.  Why? It is all about pheromone detection.   Females release specific chemicals called sex pheromones from abdominal glands whose sole purpose is to aid in attracting males.  The chemicals may be specific to the species or may be a unique combination of several agents.  The pheromones are released into the air and are dispersed through diffusion and air currents.  The tiny filaments (sensilla) composing the male moths' antennae have receptor sites for that/those specific chem...
Post a Comment
Read more

Christmas is a time for family

Image
The Svendsen Clan - Missing are Jennifer, Katie, Josh, and Chanelle The above photo was taken in 2017.  That was eight years ago, and a lot has changed.  My dad passed away three years ago, and my son and his wife now have two children.  That's the thing about families; they change. Everyone is busy.  School, work, just life in general.  As we get older, there seems to be less and less time for family.  The fact that people move away makes getting together even more difficult.  The family we knew as children has changed drastically as we move into adulthood and eventually old age.   The three things affecting that change revolve around the very nature of life.  Birth, death, and health.  While there is life, there is the opportunity to connect, to be involved in the lives of family, and possibly to make a difference.  It's not just about keeping in touch; it's really about loving, supporting, and building up.  Family means...
Post a Comment
Read more

The common candy-striped spider

Image
 ( Enoplognatha ovata - ovata morph) This spider is endemic to Europe, but it has been unintentionally transplanted to North America.  It originally settled on the east and west coasts somewhere around 1900 and, in 125 years, has managed to populate almost every state and province.   There are three varieties or morphs of the candy-striped spider.  The one I photographed above is the ovata morph, which possesses a broad red stripe across the abdomen.  The rest of the abdomen varies from cream to yellow in colour.  It is the least common of the three.  The redimita is similar, except instead of the the single, broad stripe, two thinner stripes parted by the midline are present.  The third variation has a pale green/yellow abdomen with dark spots present. Many spiders have a bit of red on them and are not terribly poisonous.  The candy-striped spider belongs in this category; its bite is mildly annoying at the most, unless you are al...
Post a Comment
Read more

Common goldeneye ducks on Mission Creek, Kelowna

Image
Common goldeneye ducks, males and females, on Mission Creek in Kelowna.  Video below. My wife of 37 years and I went for a walk down the Mission Creek greenway yesterday.  We saw quite a few birds, including a falcon of some type, although I couldn't identify it.  The best thing we saw was two groups of goldeneye ducks as they lazily floated down the creek, ducking under the surface to feed as they went.  Our presence stopped their foraging habits.  They continued along with the flow; you can see the video below. I have seen Barrow's goldeneyes recently, but not the common variety for about 4 years now.  And I have never seen this many together at once.  Apparently, they are isolationists during breeding season but group together the rest of the year.  Given that it is December, the flocking behaviour was understandable. What was interesting was that a male hooded merganser was present with them.  I saw paired mergansers along the walk, but t...
Post a Comment
Read more

Photographing in fog

Image
Fog is notoriously difficult to photograph, and not just due to exposure issues. Fog could be described as wet air.  Technically, it is a colloid, which describes any medium that suspends tiny particles that do not settle out easily.  Other colloids you may be familiar with include mayonnaise, smoke, milk, and paint.  The thing about colloids is that the tiny suspended particles scatter light, which is why you can't see well through them, especially if they are particularly dense.  Shooting in dense fog is challenging due to the lack of clear subjects.  As the density of fog decreases,  there is less scattering of light and elements of a scene begin to emerge.   The thing to realize when photographing in foggy situations is that you will need to overexpose your images by one to two stops, more if it is warranted.  In automatic modes, that means using exposure compensation or exposure lock if you can find nearby objects that are not too washed...
Post a Comment
Read more

What is the golden hour in photography?

Image
Pitt River Bridge in Maple Ridge, photographed15 minutes before sundown. I love photographing landscapes during the golden hour.  When is that, exactly?  It is the time, an hour before sunset or an hour after sunrise, in your area.  The time varies dramatically depending on the season (tilt of the Earth relative to the sun) and the geographical location.  For example, the above photo was taken at 4:12 pm on January 3, 2014.  Sunset was at 4:27 that day, meaning the shot was taken 15 minutes before the sun would set behind the horizon. Why is the golden hour considered important?  It all comes down to light quality and shadow density.  As the sun gets lower, light must travel through more and more atmosphere.  The atmosphere does three things.  First, it reduces the intensity of the light as the number of particulates increases.  Second, as light passes through the atmosphere, the nitrogen and oxygen molecules scatter the blue wavelengths...
Post a Comment
Read more

The lakes around Whistler - what causes the different colours?

Image
Whistler Valley from near the top of Whistler Mountain.  Photographed August, 2015. Blue.  Green.  Aquamarine.  These are some of the lake colours you see when visiting Whistler.  But what makes these such different colours?   Arguably, we all know water is blue, but it really isn't.  Pure water is clear, and pure water in a shallow lake will also appear clear, revealing the bottom.  As the water gets deeper, that transparency slowly disappears.  That's because water absorbs light, long wavelengths (warm colours) faster than shorter wavelengths (cool colours).  As the water gets deeper, the reds and lower frequencies are absorbed first, leaving the higher frequencies, like blue.  Thus, deep water appears blue. Shallower bodies of water may reflect more of the warmer colours, making them appear greenish.  This tendency is increased with the presence of phytoplankton like diatoms and other pelagic photo- synthesizers.  ...
Post a Comment
Read more