I've joined a recreation facility with a big, warm, outdoor swimming pool. Despite the lack of flowering plants, there are always honeybees around the pool edges. In particular, they can be found crawling over soggy dead leaves next to the pool. They're busily looking for something, but what? It's not water; when bees look for water they hover over it and attempt to land. Besides, there are shallow puddles all around. And, oh yes, this is a part saltwater pool, like the Laguna Beach pool.
So what could the bees be looking for? I don't know for sure, but maybe we can guess, based on the behavior of other insects and four-footed animals.
Worker bees spend their lives hunting for and feeding on flower pollen and nectar. Often there are butterflies flying around the same flowers, for the same reason. But butterflies can often be found on the ground — clustering around drying mud, puddles of horse urine or walking around on droppings. Like bees, butterflies feed mostly on flower nectar. So when you live on sugar and water, where do you get your minerals?
Salt licks are great attractions for deer and other hoofed animals that eat mostly grass or other plants. Elephants make regular trips to special spots where they can get salt, an essential mineral. We understand this about animals with backbones and fur and teeth like us, but bees and butterflies seem to be so different from us as to be almost alien.
How really different are they?
Fruit flies living in labs get diabetes from their high-sugar diet of yeast and banana powder. They also have heart attacks. When geneticists compared the genomes of humans and fruit flies, they discovered that we share 75% to 80% of our genes.
Those shared genes include all the ones for building, dividing and running cells; putting cells together into tissues and organs; communicating between cells, tissues and organs; and much, much more — all the essential housekeeping genes for an animal body. These basic genes are really ancient — we haven't had a common ancestor with insects for at least 500 million years.
Almost all of the remaining 20% of our genes are shared with animals more closely related to us. They include genes for cartilage, backbones, skin, fur, liver, hormones, etc. Our human uniqueness resides in a mere one-tenth of a percent of our genes.
Salt is such a fundamental nutrient that human kidneys evolved to be salt-sparing: excreting the water, but saving the salt. They work so efficiently that in our modern world of plentiful salt, we now have to limit our intake to avoid high blood pressure and other health problems.
Getting back to the bees, my guess is that they're harvesting salt from those drying, saltwater-sodden leaves. Now all I need to find is an identical chlorinated pool to check out my hypothesis.
ELISABETH M. BROWN is president of Laguna Greenbelt Inc.