I’ve been worried about the native bees. So far this spring we’ve had very few nice days, and I haven’t seen many native bees. Today, though, when the skies cleared for a few moments, I saw this big bumble in the azalea bush. I actually heard it long before a saw it–a deep, rumbling buzz you couldn’t mistake for anything else.
Footprint pheromones, also known as trail pheromones, are common in social insects. Researchers found that surfaces where honey bees have walked become attractive to other honey bees. This observation led to the discovery that honey bees excrete a chemical signal (pheromone) from their feet as they go about their daily business.
At present not much is known about the chemistry of these pheromones. But if worker bees are forced to walk over a surface, especially of glass or plaster of Paris, these surfaces can be moved and used to attract worker bees to a different location.
In theory, footprint pheromone is used for orientation and may aid the workers in finding the hive entrance or in locating a good food source, but the specifics are not known.
Some research on bumble bees has shown that footprint pheromone left on flowers is at first repellant to other bumble bees (perhaps indicating the nectar has already been taken) and later turns attractive (perhaps signaling that the flower has had time to replenish the nectar supply.) But again, the research is preliminary and much remains to be discovered.
Sonication—also known as buzz pollination—is a method that some bees use to release pollen from stubborn flowers. Plants such as tomato, potato, blueberry, and cranberry have flowers that do not easily release their pollen. Bees capable of sonication grab onto these flowers and vibrate their flight muscles (without moving their wings) until the pollen is shattered loose. Once the pollen is freed the bees groom it from their bodies and pack into pollen sacks for the trip back to the nest.
The most famous sonicating bee is the bumble bee, but there are also a few solitary bees that do it as well, such as Australia’s blue-banded bee. Tomatoes grown in greenhouses (where there is no wind) are completely dependent on bumble bees to set fruit. Honey bees are incapable of sonication and so are useless for those crops that absolutely require it.
Crops such as blueberry and cranberry can be pollinated by either honey bees or bumble bees, but bumble bees are much more efficient because of their use of sonication. If honey bees are used to pollinate those crops, vast numbers of foragers are required to get the job done.
That’s a bumble bee in the upper left. Does anyone recognize the rest? I think the lower left is a fly, and maybe the other two are bees. Any help is greatly appreciated!
The thing to remember about pesticides is this: they are designed to kill living things. As it happens, living things have a lot in common. There’s a very old saying, “the dose makes the poison.” That just means that if you keep giving something a greater and greater dose, eventually you will kill it.
The chemical companies would like you to believe that their products are specialized to kill certain things and spare others, but that is largely a myth. Some insecticides kill fish, some rodenticides kill birds, some acaricides kill bees. And of course Raid contains an insecticide and a bumble bee is an insect—no surprise there.
Most of the insecticides used on farm crops used to be applied before the bees were brought in for pollination. Although this did nothing for the wild bees, it lessened the pesticide exposure to the managed bees. But since the systemic insecticides came into use that system doesn’t work even for managed bees. The poison goes throughout the plant, the bees eat the pollen, and . . . bingo . . . the manufacturers deny everything.
Besides the poisons I usually write about, there are many other classes of pesticides, including avicides (kill birds), molluscicides (kill snails and slugs), nematicides (kill roundworms), piscicides (kill fish), and predacides (kill vertebrate predators.) Wow, that last one hits close to home. As you can see from this list, the distinction is mostly one of degree—what’s the difference between a rodent and a vertebrate predator, other than size?
Still, I doubt we will ever stop using pesticides completely, because in addition to the long list of “cides” above, I failed to mention the antimicrobials, which kill bacteria, viruses, and other pathogens. So, sure, your penicillin tablet is a pesticide.
I believe there will always be legitimate uses for pesticides, but the truly dangerous thing is the indiscriminate use of pesticides by people, companies, or governments who don’t understand how they work and the harm they can do. If we could just remember one thing—that pesticides kill living things—I think we could go a long way toward more judicious use. After all, who of your best friends isn’t a living thing?