Essays
Moseying: Exploring the Natural World
When the honeybees are gone, we will need our native bees
October 1, 2008
Have you ever taken a look at our native bees? A really close look? Most folks only see the tiny shape darting among the flowers, and a few folks get all stressed out that they might get stung, but most of our native bees are “invisible.”
Bumblebees are not invisible. As they blunder about in the flowers they are companions. I do not know why, but most folks find them amusing and rarely get scared of them. If someone ever makes the mistake of stepping on one of their underground nests, however, all “heck” breaks loose. Bumblebees form colonial nests, usually underground, in an old mouse’s nest. They fill the nests with honeypots full of honey and defend it. If you ever do step on one of their nests, FREEZE! Don’t move a muscle! A half dozen bumblebee stings is worse than a dozen wasp stings or a half-dozen scorpion stings. If you run, they catch up during the first 50 yards. But if you freeze, they just swarm, circling in the air, waiting for something to move to sting.
All bees are manipulated by plants. The nectar that bees eat is for one thing – so the flowers get pollinated. The sugar is the reward. Too little nectar, the bees do not visit. Too much, and the bee will only visit one plant and not carry the pollen from one plant to another. Since the nectar is “dribbled” out in small proportions, this may explain why most places have many species of flowers.
Bees are the third “pickiest” of the pollinators. A sphinx moth needs at least a 51% solution of nectar. Butterflies like at least a 44% solution, but bees are happy with anything above a 37% solution. Some bees and other pollinating insects are generalists, and usually feed on flowering perennials, shrubs, and trees. A number of species of insects, especially bees, are specialists, and only feed on annuals that often only bloom for short periods of time. (In west Texas, the best flower seasons are April and September.) One entomologist, during a presentation, commented that “every species of annual wildflower probably has its own species of native bee.”
Some plants, however, have a large number of pollinators. For example, creosote bush, the indicator plant of the Chihuahuan Desert, has 84 species of bees that feed on the shrub’s flowers. Several species only feed on creosote bush, and it only blooms after a rain. And rain showers often come months apart, so just how do the bees appear at just the right time? Creosote bush will bloom after even a quarter inch rain, but after a two inch rain will bloom profusely. As the bees lay under ground in their pupal cases, does it take a certain level of moisture in the soil to stir them “to life?” The mysteries of adaptation still await a multitude of discoveries before we humans can understand a mere bee!
Have you ever heard of a short-tongued bee? It is a whole family of bees. They nest in the ground, in hollow stems of plants, or even dig out softwood of a shrub to make a tunnel. They carry the pollen and nectar to their nest in their crop (or honey stomach), not in hairs on their body, or in pollen bags on their legs like other bees. In the hollow tubes they build partitions with their saliva. That is why they have short tongues! In each cell an egg is laid on top of the stored nectar, which remains in a semi-liquid state. Most of these bees are specialists, and are only seen when their favorite species of wildflower is in bloom.
When folks wander about West Texas, they sometimes find a colony of “digger bees.” In one small area, hundreds of individual holes will be visible. Mounds of dirt surround each hole. Every bee in the colony will be a female. She lines each cell with a silky material that still has not been identified, then builds a loaf of pollen, and lays an egg on it. Most digger bees are very hairy.
Digger bees have a number of enemies. Beeflies are the worst. They sort of look like bees, and they often hover around flowers, waiting for bees. Some lay eggs on the female bee as it feeds, other species follow the bee back to the "digging grounds” and divebomb the nest with eggs. When the bee fly egg hatches, it lives in the cell where the bee egg is. Some species eat the pollen and ignore the egg. Others will eat the baby bee in its larval form. Other species will become internal parasites, living inside the adult digger bee’s body and then emerge when the bee is in the nest, and then parasitize the larval bees, but only begin to feed when the larval bees pupate. All of this does not kill the bee, however, just renders them sterile!
A small species of beetle is also an enemy of the digger bees. The beetle waits on flowers, and grabs the bee’s hairs when it visits, and catches a ride to the nest. After the bee leaves an egg, the beetle eats the egg, eats the pollen cake, moults, eat a bit of stored honey usually consumed by the emerging bee of the next generation, then the beetle spends the winter as a “pseudo-pupa” and finally emerges from the ground the following year.
The complexity of the life histories of the native bees is beyond belief. The many complicated progressions of life are mind-boggling. We probably only know 25% percent of the story. Most insects that do not effect humans are poorly studied. It is only in the last few years, with the threat of the collapse of the honeybee populations due to disease and other factors that have scientists really began looking at native bees. If we do not learn how our native pollinators behave, and how we can enlist them to help pollinate our crops, modern society may be in desperate times. Honeybees are beset with troubles, and honeybees pollinate most of our food crops. When the honeybees are gone, we will need our native pollinators!