Last time, I talked about how global warming is going to affect our pollinators, and alter our food supply. Not only are water resources going to shift as average temperatures increase, but also the life cycles of our pollinators are going to change dramatically.
To understand how and what that will mean for our farmers, it's important to know about the insects themselves.
In this part of the series, I'm going to talk about mason bees. This gentile gentle pollinator is a new favorite of orchard farmers, owing to their extremely efficient pollination of fruit trees.
Mason bees go by many names. Orchard bees. Blue orchard bees. Orchard mason bees. One common species in the western United Statees is osmia lignaria. There are other species in osmia, like cornifrons, ribifloris, and californica. Each has been cultivated from wild populations to serve a specific argricultural need. Lignaria for cherries and almonds, californica for sunflowers and other summer flowers, ribifloris for blueberries, and cornifrons for apples (in Japan!).
Now everyone is familiar with the honeybee. Their signature yellow and black bodies are found all over the globe. But the domestic honeybee is an import to North America, having originally come from Europe. Honeybees are great general pollinators, but they won't visit every flower.
There are many native mason bee species in the United States already pollinating our crops. And now farmers are beginning to appreciate how the domestic mason bee can be the better pollinator in many cases.
Mason bees are solitary, unlike honeybees. That means that each female is reproductive and there is no queen. But while mason bee works alone, they are gregarious. That is, they don't mind nesting nearby each other.
Also unlike honeybees, they have a much shorter flying season. Mason bees are typically found flying in the spring when they emerge from hibernation and feed off of the plentiful blossoms.
But when they fly, they waste no time. One mason bee female can pollinate 60,000 blossoms in her very short life! Farmers time their emergence to correspond with the bloom, often doubling or tripling their crop compared to years when they only used honeybees.
Life Cycle
Blue orchard bees emerge from their cocoons in the spring when the daytime temperature reaches 14ºC (57ºF). The males emerge first and remain near the nesting site, waiting for the females. Mating season can be several days to weeks depending on the number of continuous days of warm weather.
Lignaria females like to nest in narrow holes or tubes, though they have been found to nest inside cedar shakes and even keyholes. Beekeepers put out pre-made nesting materials to entice the females to stay close to the orchard. She flies outside of the entrance and does a in-flight dance to orient on major visual features in order to find her nest again when she returns from foraging.
Orchard mason bees arrange their nests as a series of partitions, with one egg per partition. The female bee begins the process by collecting mud and building the back wall of the first partition. Then she makes trips to nearby flowers. She prefers flowers that are nearby the nest (unlike honeybees). She can visit 75 flowers per trip, and it takes 25 trips to create a complete pollen/nectar provision. She works tirelessly during the day, only stopping once the sun has gone down. When the sun rises the next morning, she will bask in its rays until she is warm enough to fly. Then she continues where ever she left off the day before.
Once the provision is complete, she backs into the hole and lays an egg. She collects more mud to seal off the partition. She continues until she has filled the nest, leaving about an inch of space in front without any eggs to protect her brood from predators. Lignara, like many insects, can select the gender of the egg they lay by fertilizing the egg, or not. Unfertilized eggs are males, while fertilized eggs are females. The adult bee lays female eggs in the back of the burrow, and the male eggs towards the front. She lays about three males to every one female.
When the egg hatches, the provision provides the bee larva food for most its life; It won't see daylight until the following spring.
She plugs the entrance with one thick mud wall and then she seeks out a location for a new nest. She'll work until she dies.
Effect of Global Warming
I mentioned in part 1 that I keep mason bees. Last year, we saw an unseasonably warm spell in January followed by 40 days and nights of rain, rain, rain.
Remember 57ºF from above? The warm spell caused the bees to emerge early, but there was too little food for them. After waiting patiently for the flowers, the rains came. Since they can't fly in the rain, most of the population died of starvation.
Domestic populations that can be refrigerated are going to fair better (like mine are now), but that's not healthy for the wild populations, or for orchards where over-wintering thousands of bees in a temperature-controlled refrigerator is impractical.
Native mason bee species fly all through the spring and summer, timed to emerge with their favorite food sources. As it grows warmer, they will come out earlier, and perhaps starve.
Later-flying species might do better, but that's only if their preferred nectar and pollen sources are still timed with their emergence. Just because mother nature timed the bees to temperature doesn't mean that she timed the flowers to the thermostat as well. Plants are pickier. They like to wait for the temperature and the humidity to be just right.
Orchards that depend on mason bees and other pollinators (either directly or indirectly) are going to see their crop yields dramatically affected. Honeybees are already declining North America. If the native pollinators decline too, the apple, cherry, blueberry, apricot, peach, nectarine, almond, pear, etc. crop will lower as well.
Once the climate starts to change, our ecosystem will be poorer. Worse, our fields will produce less as there will be fewer native pollinators, and it will cost farms more money in pollinator maintenance to produce the same yields year after year.
The affects can be minimal, like lower yields resulting in a modest increase in produce prices and more land being converted to agriculture. Openspace would be lost, of course, and that would terrible for our wildlife, and the native bees that they harbor (which pollinate our crops and get no credit!)
Or more likely the price of produce will significantly increase and the more exotic fruits and vegetables will become scarce, in addition to substantial losses in openspace and wildlife, which will accelerate the decline in pollinators and crop yields, which will contribute to even higher prices, less openspace, and the complete elimination of certain hard-to-pollinate crops.
The price of beef is going to be skyrocket, too, since a cousin of the mason bee, the alfalfa leaf-cutting bee, pollinates the primary food source of our nation's livestock.
In short, global warming is bad for us in more ways than people know. And the global-warming-deniers who claim that there will be more arable land are simpletons and idiots: there is no crop without pollination, and there will be no pollinators in a post-global-warming world.
Next Sunday, we're going to look at the honeybee, probably the most famous insect in the world (and most useful!).
Previous Entry in this Series:
Part 1: Global Warming kills bees