Turkeys, migrating birds, and migrating butterflies
Well, Thanksgiving is over. Hope you all had a good THANKSGIVING HOLIDAY! Is there still any leftover turkey?
I read an interesting fact about turkeys in the Saturday Evening Post. Apparently, turkeys have a weak heart, and nearly a million of them die because of this every year on turkey farms in this country (November-December 2014 issue p 31). I decided to look into this briefly and searched for ‘Turkey health problems” on the Internet. I didn’t find the exact statement about weak turkey heart – I didn’t look long or hard; maybe some of you will find it. But I did come across a handout on turkey care at farmsanctuaty.com. They say there that commercial turkeys are fed on a high-fat diet often supplemented by antibiotics, and that this leads to health problems and early death. It would be reasonable to assume that heart problems may be the result of a high-fat diet and of an enormous body (the result of overfeeding), and that these could lead to early death.
I thought I would also search for “interesting facts about animals” in the hope of finding some detail about the weak heart of turkeys. I had 60,200,000 results. I came upon a great many sites that list and show animals, mainly furry or feathered, with some interesting facts about them (though I did not find the turkey in a short search). I followed the hits on the first page; the sites are somewhat repetitive, so you don’t have to look through all 60 million. I don’t want to spoil the fun in case you decide to look these up, but:
Did you know that a group of flamingos is called flamboyance?
Did you know that ‘aside from when nesting, a common swift will spend its entire life in the air’?
Speaking of swifts: have you ever thought about the wonders of bird migration? There are, of course many sites that provide information about bird migration.
How do they manage these long flights? How do they know which direction in which to fly, and where to go? According to a short description in the November 2014 issue of the Scientific American (p 22), the flight path for a bird is ‘stored at least partially in its genes’. An interesting experiment was performed with hybrid birds (thrushes) that had one parent taking a route close to the west coast of North America towards Mexico, and another parent, that flew through the east-central part of the continent. The flight of the hybrids was followed with GPS trackers. The hybrids either took intermediate routes, or followed one parent when flying away, and the other one when flying back. (Some chose to fly according to one parent only.) There are plenty of questions to ask about this study, which is just the latest in the quest to understand bird migration, and how these traits could have evolved. But as the article says, the birds must have an innate flight plan. And it shows one way their flight plan can change.
Talking about migration, Monarch butterflies from North America migrate to the mountains of Mexico. Monarchs that live in tropical areas, perhaps not surprisingly, do not systematically migrate. Monarchs now also live all over the globe, and they don’t cover long distances like the ones from the Northern United States. Now, in an effort to understand about genetic differences between migrating and non-migrating butterflies, a group of scientists undertook a remarkably extensive DNA sequencing study of monarchs. They examined single building block differences (single nucleotide polymorphisms) in the total genetic material (genomes) of 89 butterflies. (Another 12 individuals were analyzed to learn about the coloration of Monarchs, making the total number of individuals sequenced 101!)
Collagen triple helix
The results from comparing butterflies from all over the world show that the North American monarchs are the ancestors of the non-migrating ones. This is the opposite of what is believed about birds. According to the accepted theory, the ancestors of migrating birds are the tropical non-migrating species.
The above studies also highlighted several genes that were associated with migratory behavior. Among these were genes involved in the development of morphological features and of the nervous system. The strongest link with migration was found for a gene coding for collagen. Collagen is the main component of connective tissues. It has a crucial role in forming fibrous tissues, and surrounding muscle fibers. This latter function is the one that, when diversity is found in the collagen gene product, is likely to influence the ability for long-range migration, as the fine structure of muscle may define what exertion the monarchs are capable of.
Turkey care from www.farmsanctuary.org
Which direction home? Some migratory birds get conflicting instructions from Mom and Dad. Goldman, Jason J, 2014 Scientific American 311 No 5 p 22
Of Monarchs and Migration Richard H. Ffrench-Constant Nature (16 October 2014) 514, 314–315
Reporting on: The genetics of monarch butterfly migration and warning colouration. Shuai Zhan, Wei Zhang,Kristjan Niitepõld, Jeremy Hsu, Juan Fernández Haeger, Myron P. Zalucki, Sonia Altizer, Jacobus C. de Roode, Steven M. Reppert & Marcus R. Kronforst Nature (16 October 2014) 514, 317–321