With Honey bee populations in decline due to Colony Collapse Disorder (CCD) and other factors, one study conducted by researchers at North Carolina State University and the University of Massachusetts seems to offer some hope. It showed that two different species of bees fed a diet of sunflower pollen had dramatically lower rates of infection by specific pathogens. These pathogens have been implicated in slowing bee colony growth rates and increasing bee death. Bumble bees on the sunflower diet also had generally better colony health than bees fed on diets of other flower pollen.
However, the study also revealed that Honey bees on the sunflower diet had mortality rates roughly equivalent to that of honey bees not fed a sunflower pollen diet, so the positive short term effects don’t include longevity. Bumblebees, (our most efficient pollinators) didn’t seem to have the same problems with longevity.
Bees are adept at collecting sunflower pollen. Annually, some two million acres in the United States and 10 million acres in Europe are devoted to growing sunflowers, making sunflower pollen a ready and relevant bee food.
Sunflower pollen is low in protein and some amino acids, so it’s important that bees have many diverse wildflowers to choose from in addition to sunflowers, especially for generalists like bumble bees and honey bees.
Bees fed exclusively sunflower pollen often develop poorly, slowly, or not at all. What remains a mystery is that many bee species who are not generalists like Honey or Bumblebees collect pollen exclusively from the sunflower family; in fact, it is believed that bees specializing in sunflower pollen have evolved multiple times.
Another study done on (solitary) Mason bees discovered that bee species specializing in sunflower pollen were not attacked by a common brood-parasitic wasp, (Sapyga). One probable conclusion is that some bees, at least, are protected from (some) parasites by feasting on sunflowers; this may help explain the frequent evolution of specialization on sunflower pollen among these insects.
While I was researching bee related articles I came across some startling and disturbing information about the use of pyrethrum. Pyrethrums are naturally occurring compounds extracted from chrysanthemum plants that are used to make pesticides; this family includes sunflowers. Pyrethroids have the same basic chemical make-up but are not naturally occurring and are a man-made product also used as pesticides.
What I didn’t know is that pyrethrum is considered to be a low toxicity pesticide only from a human standpoint.
Supposedly, there is also a relatively low toxicity level with respect to birds and mammals. (I can’t help wondering how many non – human species have actually been studied). What we do know is this natural insecticide is toxic to cats and extremely toxic to fish. It follows that amphibians would also be negatively impacted by the use of pyrethrum. And what about the catastrophic decline in songbirds who are the proverbial “canaries in the coal mine”?
Animals that are exposed to toxic amounts of pyrethrum may experience loss of coordination, paralysis, convulsions, respiratory failure, and death. With bees, foraging behavior may change, and as with more deadly agricultural pesticides, the bees may lose their ability to learn the skills needed to extract nectar and pollen.
According to a recent New York Times article the Earth has already lost 80 percent of her insect population for reasons are ‘unclear.’ Yet we know how deadly the use of backyard and agricultural pesticides are, and we continue to use them. How is it that we didn’t pay attention to insect losses until CCD occurred with our bees? Our astounding lack of awareness and attention with respect to Nature is backfiring. Without insects as pollinators, humans will be left without food. We are all connected. Clearly there is an increasing need for field-realistic research into the reasons behind the decline and loss of any species and the impact of any pesticide on bees, humans, and non – humans alike.