Three swallowtail species and hybridization.

 

At first glance, the Canadian and pale tiger butterflies above look to be the same species.  A third butterfly (below), the western tiger swallowtail, is similar in many ways to both of the above species.  The three species live in British Columbia and their ranges overlap to some degree.  It is in those places that the species may interbreed producing hybrids.

There is an interesting post on the website E-Fauna BC that discusses the hybridization; I have included the paragraph below.

All the tiger swallowtails (subgenus Pterourus) hybridize in the wild to some extent. In southern BC there is a broad zone of hybridization between Canadian Tiger Swallowtails and Western Tiger Swallowtails from Manning Provincial Park east to Creston. In the areas where their ranges overlap, Western Tiger Swallowtails prefer low-elevation deciduous forest habitats whereas Canadian Tiger Swallowtails prefer higher-elevation boreal forest habitats. Hybridization between Pale Swallowtails and Western Tiger Swallowtails is rare, but Wagner (1978) collected a perfectly intermediate male hybrid in the wild in Idaho. Jon and Sigrid Shepard found a male hybrid of the Pale Swallowtail and the Canadian Swallowtail 10 km south of Galloway, BC. lt is intermediate in appearance between the two species.

The whole idea of hybridization between species has value as it could promote an exchange of genetic information to ensure the survival of the genus.  The problem with most hybridization within close species is that the offspring are often infertile and not capable of producing viable offspring.  The reason often has to do with the number of chromosomes each species has.  Donkeys, for example, have 62 chromosomes while horses have 64.  The mule, a hybrid, has 63 and thus is deficient in some genetic material which renders them sterile (incapable of producing viable offspring).  There is a very interesting website discussing butterfly hybridization here.

Thanks to the various websites and authors for putting together the information.  I found it very interesting.

Thanks for reading.

Eric Svendsen     www.ericspix.com

Comments

Post a Comment

Popular posts from this blog

Hang in there, things will get better.

Image
The Svendsen Family - Eric, Samuel, Leanne, Joshua (top row), Nora, Kathryn, Chanelle, Emma If I could go back, in my mind, to a day in my life when I was really down, it would be nice to be able to see into the future.  If could see things as they are today, with the many blessings that have been given to me, it would give me hope knowing that things wouldn't always be so discouraging.   The message here is we do not know what the future holds.  When things are bad, it is hard to raise your head out of the mire to see beyond the darkness.  There are no guarantees, of course, that things will be better, but I think it is true that fortunes ebb and flow as tides do.  The trick is to see beyond the low points and not be too haughty during the high ones.  I know that, at this moment, things are very good.  What the future holds is unknown, but low and high points are likely in the forecast.   This is why taking satisfaction from the moment is so important.  Instead of looking forward
Read more

Northern Rough winged swallow

Image
Northern Rough Winged Swallow - a new species for me. There are a number of bird groups that I find hard to identify species in.  The ones that immediately spring to mind are gulls and flycatchers. The key to identifying a bird species is to look for morphology clues such as size and colour.  Particular features such as beak and leg form will often help you to identify a bird to at least the family level.  Beyond that, you need specifics such eye rings, breast pattern, wing or tail bars, and so on.  Habitat, behaviour, and location may also play a role in identification. In the example above, my thinking is that the bird is a flycatcher.  It doesn't fit any of the patterns for the swallows we have here.  There is no eye ring, no crest, and the bird is has a buff-coloured breast without a pattern and a brownish-coloured back, sides, and wings.  There are no wing or tail bars.  It is also small in size.  This leads me to believe it is either a pewee or phoebe.   Given the fact that I
Read more

Working out life's problems.

Image
Kathryn and Eric - together for 35 years. Whoever said life is easy hasn't been alive for very long.  Yes, although there may be times when everything sails along very nicely, the truth is that hardship is just around the corner, in both directions. The essence of the problem is that we are imperfect beings and we live in an imperfect world.  Bad things happen, both to us and those we care about.  We make decisions and take actions that others may oppose or be hurt by.  Even when, after much thought and research, we do what we think is best or right, our opinions or behaviours are not approved by those we love.  People get hurt, and sometimes the hurt leads to serious repercussions.   I can say that Kathryn and I are happily married.  But I can also say that our relationship has gone through difficult moments.  A great deal of the challenges we have faced have come about because of differences in opinion, differences in problem management, and difficulties in effective communicatio
Read more