Sunday, March 2, 2014

The Importance of Native Pollinators

Bumble bee visiting a sunflower. © 2010 Beatriz Moisset
At the risk of repeating myself, I want to discuss once again the widespread erroneous belief that we depend entirely on honey bees for the pollination of one third of our food and that we would all die if they were to disappear. Honey bees are not the only pollinators. We must value all the others and we should learn to take advantage of them for our crops' pollination.

We must remember that 4,000 species of native bees populate this country; 20,000 the entire world. They vary in size, appearance, season of activity, flower preference. . .  Some live in colonies similar to those of honey bees, but most are solitary and nest in holes in the ground or in hollow tubes inside soft pitted canes or in holes left behind by beetle larvae.

All of them combined are tremendously important, not just for the pollination of wild flowers but also of some crops. In fact, all the crops pollinated by honey bees could be taken care of by one or another of the numerous species of wild bees.

A few examples of the marvelous things native bees do

*Bumble bees and several solitary bees pollinate tomatoes, peppers and eggplants. Only they know how to manage their flowers. Honey bees cannot do it

*The alfalfa bee and the alkali bee pollinate 80% of the alfalfa flowers they visit. Several bumble bees do just as well. The batting average of honey bees is a mere 20%

*A single southern blueberry bee can pollinate $20 worth of blueberries (probably more at current rates). Honey bees don't come even close

Osmia  sp., a mason bee. © 2007 Beatriz Moisset

*An acre of apples can be pollinated by 250 female orchard mason bees. This task would require 1.5 to 2 honey bee hives—approximately 15,000 to 20,000 bees

Squash blossom. © 2014 Beatriz Moisset

*Squash bees are up early in the morning, when squash flowers are at their peak. Later on, when bumble bees and honey bees arrive, most of the pollination has already taken place

*When the weather is bad, too cold or wet, some native pollinators go out anyway. A few work before sunrise or after sunset. The honey bees prefer to stay home under these conditions

An assortment of pollinators provides a degree of insurance. When the population of one species  declines, as it is bound to happen some years, other species take over the slack. This is one of the advantages of diversification. We have depended for too long on just one species.

Despite the advantages of this variety of native pollinators, farmers often resort to honey bees because the wild pollinators are, well, wild, not easily controlled. Honey bees provide a large task force that can be managed and transported where needed. They are perfect for large monocultures, with only one kind of food temporarily available and nothing else the rest of the year.

We shouldn't ignore the contributions of native bees. They can do a superb job at small or medium sized farms. Managing them would require a healthier habitat and less pesticides. A polyculture, the opposite of a monoculture, would also be important.

We are reaching a point in which we cannot rely entirely on just one species of pollinator. The task of changing cultivation practices is huge but it can be done and it needs to be done. The Xerces Society and some universities are committed to developing the ways of putting native pollinators to good use. The results have been highly encouraging.

Long-horned bee on sunflower. © 2007 Beatriz Moisset


Additional readings

Farming with Pollinators, the Xerces Society
Wild Pollinators, Agriculture’s Forgotten Partners. WildFarm Alliance
Native Pollinators. Wildlife Habitat Council

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2014