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COLUMN: When it comes to mating, bigger may not be better

When it comes to reproduction in the local forests and streams, all may not be what it appears to be, says columnist
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A pair of sunfish are shown in a stream in the Copeland Forest. When it comes to mating, all is not what you might expect, columnist explains.

Buck, boar, ram, or drone. Gander, drake, or rooster. Billy, Tom, or Jake. Behold the mighty male! Good ol' dad. Father's Day is once again upon us and we all need to make some time to appreciate what the male of the species contributes to the whole life cycle thing; after all, he is a rather integral part of the system.

Yes-siree-Bob, if it weren't for males this whole "life on the planet" idea wouldn't have gained much ground.

As I was growing up and began looking at our natural environment and all the creatures in it as being something more than a target for my BB gun, a couple of axioms appeared time after time: only the fittest survive; and only the deer (or moose or elk or mountain goat) with the biggest antlers or horns got to pick which female would be the mother of his children. In other words, wimps need not apply.

I took these words at face value, because it seemed to make sense. Big, brave, brash and healthy males certainly stood out as the ones which rounded up a harem.

The assumption was that the lesser males simply backed down and found a quieter pasture to graze in. (Man, this sounds like high school... but I digress.) However, some things are not always as simple as they first appear, especially in nature.

Take the feisty sunfish as an example. The males of this fish species construct a nest in the gravel beds of a lake, near the shore. By swishing debris and sediment out of the way, a lovely washbasin-sized nest appears, and the male waits poised over the centre.

When a sweet little lady fish swims by and drops in to deposit her eggs, the male swims down beside her and covers the eggs with spelt, thus fertilizing the eggs. After the missus leaves, the ol' boy guards the nest until the eggs hatch into fry.

For many years it was thought that this was how the bluegill sunfish reproduced, and that only the biggest male fish would ensure that their DNA is passed forward. But a bit of research revealed a rather complex and titillating story of what really happens in the sunfish's nest.

In the 1980s, author Adrian Forsyth wrote an essay in Equinox magazine that plumbed the depths of sunfish breeding, which I will greatly summarize here. 

While the biggest and bravest of the bluegills built impressive nests and swaggered about, chasing away anything that came within range of their magnificent nest, there are several meeker male bluegill sunfish that hang about, doing nothing at all. At least until a female fish appears at the nearby nest.

As the new couple swim lazy circles around the gravel nest, the satellite male (as they are called) slips in between them. Being small and without blazing bright colour, he is mistaken by the home male as being another female. As the real female rests on the gravel and releases her eggs, both males cover them in a cloud of sperm. Then the little weasel disappears, leaving the big lug to protect the nest and the cluster of eggs that have now been fertilized by two different males.

Further testing of these fish revealed that the satellite males had larger reproductive organs than the nest building male. Mister nest builder used his energy to grow big, brash and beautiful, while the satellite male seemed to re-direct his growth energy away from body size and focused instead on reproductive potency. Very interesting!

As mentioned earlier, white-tailed deer are known for having the biggest and strongest buck take care of his harem of does. Again, a second look has revealed that all is not as clear-cut as Disney's Bambi would have us believe. (And besides, in the movie, Bambi's dad is an elk, so what's up with that?)

A male deer spends a lot of energy in antler growth and getting a swollen neck during the rut, or mating season. He doesn't eat much at this time, as every moment is spent displaying for the does, intimidating lesser bucks, and keeping his new harem close by. Which means that he is nearly exhausted.

Sometimes a younger, smaller male will simply hang out nearby, getting to know the girls: “Hey, no pressure, no threat, just chowing down on these grasses beside you, aren't they delicious? You should try some of the wildflowers that grow just over that ridge. Come on, I'll show you.”

And so while King lords over his realm, Bucky has some play time with the girls while the boss is looking the other way. Hey, the big guy’s got more does than he knows what to with, or can count. And life goes on.

More than a couple of books have been written about the human mating game… some scientific, some not so much so. No matter what the species, at least half of the success for surviving into another year goes to the dad of the species. Mind you, "parenting" is hugely different than "reproducing", a topic which I will leave with you to discuss with the family over a Father’s Day celebratory dinner on Sunday.

 


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