Hey Dave1949:
You and I have discussed blackfly pollination of Blueberries...which I questioned.
So off I went to do my research on Google.
There is little consensus about the pollination of blueberries by blackflies amongst learned opinion. Some say yes, some say nay: yea-sayers relate folklore and conjecture supporting their opinions; nay-sayers relate to actual studies and experiments. A definitive opinion is not there on either side.
Here are some facts gained through accredited research that can be gleaned from Google in about twenty hours of reading:
1. A blueberry (sweet, low bush type) requires 14 grains of pollen to be pollinated for best fruit set. That is a big load for a blackfly to carry
2. A blackfly (110 species in Canada) eats plant nectar for energy and blood for egg formation. Both sexes require nectar, only females require blood for egg laying in clean water.
3. Blueberry blossoms yield pollen when the blossom is stimulated by the precise frequency of the wings of a bumble bee.
4. Blackflies do visit blueberries for nectar, but evade the pollen-producing pistils of the blossom by crawling around them and then sucking the nectar from the base of the flower.
5.Blackflies are not so constructed as to catch or carry 14 grains of pollen (too small) from plant to plant.
6. Commercial blueberry producers rent both honeybees and bumblebees to get best fruit yields, even where black flies are abundant
7. Blueberries are rhizomes, spreading by underground roots, not so much by seeds in the berry. Blue berry fields of hundreds of acres are possible from a single plant, and that is usual in wild berry fields.
8. Blueberries are self pollinating, by wind-blown pollen. Self pollinated fruit is late, small, and not so sweet as is that pollinated by bees.
9.Blueberries are also effectively cross pollinated by moths, bigger flies, ladybugs, etc, etc. BUT NOT by blackflies.
10. Growing experiments, using exclusion nets and such, in patches of sequestered berry plants show that cross-pollination rates are not affected by blackflies. but are very much affected by bees, et al.
The list goes on and on, until my eyes burn. My conclusion: Blackflies are capable of cross pollinating blueberries, yes...but that is NOT how the best fruitset yields originate. It is my opinion, based upon deduction (from the list above) that the major pollination of good fruitset berries results from bumble bees, which buzz-shake pollen loose from flower pistils, and wild honey bees, moths, butterflies (to) carry pollen around. And that the notion of blackfly importance to blue berry production is just folklore, albeit somewhat logical. Blackflies abound where berries grow, There are a lotta blueberry blossoms, and a lotta blackflies. Both occur in the same seasons, and in the same places. Sheer coincidence?//Maybe, but not a scientifically sound conclusion. Nope. Cross pollination is done by other kinds of bugs, lots of them.
I think blackfly larvae are good food for trout and other fresh fast water fish species. If so, we see a laudable purpose in their existence. BUT blackflies are both a pest and a threat to humans.
The bite of a female blackfly (males do not bite and cannot) carries a virus that causes river blindness,
anaphylactic shock...and so on.
Are they important to blueberries? Very dubiously, if at all. But the blackfly does discourage some human blueberry pickers, but encourages trout anglers
Oh yes...DEET insect repellant is not effective against blackflies. No kidding! Nothing is. That is why we call them awful names and wear nets.
Bush fever is a real consequence of many blackfly bites..and people die from it in the tundra areas of Canada...Doctors call it septicemia (blood poisoning) I call it death by itching.
End (finally) I hev run outa big words! Do I earn a pat on the back, or a kick in the butt... huh.
Jix
