by Vicki Blachman, South Central District Member at Large
There are over 20,000 bee species in the world. Of those, close to 4,500 are considered native to the U.S., and up to 1000 are native to Texas (I typically say “over 800”). They’re currently classified into seven families, of which six are represented in Texas. Our native bees range in size from nearly an inch long down to smaller than a peppercorn. I’ve tried to limit the scope of this article to the least I can say given that “the native bees of Texas” is a broad topic well suited to the size of our state.
As for that iconic golden yellow and black striped honey maker, the honey bee (Apis mellifera) is non-native but well established. As described by Michael Engle in 2009, it also appears to have at least one extinct ancestor (A. nearctica) that lived in North America 14 million years ago. Our challenge is that those hairy-eyed honey bees get all the love, and only recently have natives been recognized for their intrinsic value to local biomes and as the workhorses they are. Their PR needs our help.
How many people even know native bees exist? They’ve pollinated every single flowering plant in North America until the 1600s when the honey bee was imported. They’re considered at least three times as effective as honey bees for pollination. Some pollinate plants that honey bees can’t, or pollinate certain crops up to 20 times more effectively. Some, like the bumble bee, are capable of buzz pollination, a technique that honey bees lack. The takeaway? Our native bees have co-evolved over time with native plants to be mutually beneficial and mutually dependent – lose one and the other will be lost as well.
The terms “native” and “solitary” are often used interchangeably, but not all native bees are solitary, nor are all solitary bees native. A solitary bee will mate, deposit and provision her eggs, then continue laying eggs until her death four to eight weeks after her own emergence. Those eggs are left alone to grow and pupate, before emerging the following spring or early summer to repeat the cycle all over again. It’s often said each solitary bee is her own queen.
By contrast, our native bumble bees are said to be social or semi-social, having the presence of two generations in a single nest at the same time. Honeybees are called eusocial, or “true” social, due to multiple generations of individuals present, each individual having a specific role to play in the collective hive.
There are solitary bees that are non-native, bees and bee products having been imported freely until a 1922 Honey Bee Importation Law was passed. But that legislation applies to honey bees; solitary bees, which do not produce honey, continue to be imported for research and subsequent commercial use. For example, hornfaced bees (Osmia cornifrons) were first imported from Japan to Utah in 1965, but did not survive. In 1976, they were imported again into Maryland where they still thrive in a climate more like that of their home in central Japan. The delightfully named shaggy fuzzyfoot bee (Anthophora pilipes villosula) even more recently has been imported from Japan as a managed species for commercial blueberry and other fruit pollination.
Some solitary bees will form aggregations where nesting conditions are favorable. While a large number of individuals may be found using the site, only a very few species are actually communal, meaning they actively help each other. Dependent on their environment, the family Halictidae even has the unusual ability to switch between being social or solitary!
The vast majority of native bees are ground nesting. Some make cells of mud, bits of leaves or petals, resin, hairy plant fibers, wood dust, cellophane-like secretions applied with their tongues, or silk-like secretions from thoracic glands. These are placed in tunnels in the ground, abandoned rodent burrows, hollow reeds, bamboo, logs, pithy stems, softwood structures, and even holes in bricks or other man-made items such as hand tools and equipment.
While man-made bee houses may have benefits, in order to avoid predation and reduce susceptibility to disease they should be scattered about the site rather than clustered together. Bee houses should have a guard of chicken wire, or other material with bee sized holes, across the opening to prevent predation by birds. The openings should face the sun in the morning and have protection from rain and insulation from extreme cold if they’re not placed inside to overwinter. Under the Texas Death Star, it can also be beneficial to have plants growing nearby that provide afternoon shade. Habitats should also include a source of moisture and shelter from wind. In the fall, “leave the leaves”, as well as stems and grasses, for shelter.
In closing, I repeat the takeaway I’m certain many of you already knew. Our native bees have co-evolved over time with native plants to be mutually beneficial and mutually dependent – lose one and the other will be lost as well.
Photo Credits: 1) Apis mellifera (Ivar Leidus via Wikimedia); 2) Bumblebee (Niek Sprakel, public domain); 3) Osmia cornifrons (Beatriz Moisset via Wikimedia); 4) Cellophane bee emerging from its ground nest (NY State IPM Program at Cornell University); 5) Hollow stems provide nesting sites to solitary bees (Alex Lockton via Wikimedia); 6) Buzz pollination by a halictid bee (Bob Peterson via Wikimedia)