Save the Hymenopterans (Bees, Wasps and more!)

July 17, 2024

Pollinators

Hymenopterans are the group of insects including bees, wasps, ants, and sawflies. “Sawfly” is the name applied to all but one group within the hymenopterans, making this group paraphyletic – that is to say, “sawfly” includes some, but not all, of the descendants of a common ancestor. The remaining group includes bees, wasps, and ants. Similar to the sawflies, “wasp” is applied to some, but not all, descendants of a common ancestor. Another way to look at this is to say that wasps are derived from a sawfly ancestor, and bees and ants are both derived from wasp ancestors. I cannot find an exact count of the total number of hymenopteran species in Ohio, but ~750 is a good estimate.

In the past decade or so, there has been an explosion of interest in “saving the bees”, but quite a bit less information on what that actually means. The phrase is often associated with studies showing a decline in the health, vigor, or quantity of honeybee hives. What many folks take away from this is that honeybees, a native species in North America, are in peril. That is not the case. Honeybees are native to Europe, Asia, and Africa, and were introduced to North America for honey production. An argument can be made that they are an invasive species, competing with native pollinators and doing a poor job of ensuring native plants set seed. Our native bees are part of a group of insects that also includes ants, wasps, and sawflies, called Hymenoptera. These insects are in many cases at risk, due to habitat destruction, indiscriminate use of pesticides, and human-caused climatic fluctuations. The number of native bee species in Ohio is given at around 500.

Wasps have an unfortunate perception in popular culture, brought on by a handful of aggressive species. The majority of wasp species worldwide, including in Ohio, are tiny, shy, stingless insects, and play critical roles in our food web. Due to their usually shy nature and complicated interspecies relationships, there are numerous species of wasps whose life histories are totally unknown, which have yet to be formally described, or are yet waiting to be discovered.

The following photos exhibit some of the hymenopteran diversity to be found in Ohio, with emphasis on species that are little-known, or that may help overturn popular misconceptions about this group.

*Pseudosiobla sp*. June, on buttonbush. This caterpillar look-alike is the larva of a sawfly, a group of wasp-like hymenopterans. This species is a wonderful example of the host specialization often undertaken by insects. This larva feeds only on buttonbush during its development, similar to how monarch caterpillars feed only on milkweed. Such specialization is seen often in caterpillars, and is the rule in certain groups of insects that form galls in plant tissue.

*Lasioglossum sp*., sweat bee. June, on me. This individual is of the subgenus *Dialictus*. Sweat bees are tiny and harmless. They are so called for their affinity to human sweat. Though these bees obtain sustenance from pollen and nectar, something about sweat – supposedly the salt content – is attractive to them. I have had up to ten of these guys hanging out on me at the same time. They are very cute and very persistent. Attempting to swat them away works momentarily, but they usually return after a second or two for more.

*Andricus quercusstrobilanus*, lobed oak gall wasp. August, on overcup oak. This is one of the tiny, harmless wasps mentioned above. The flat, fleshy lumps seen in the photo are modified plant tissue; the wasp itself is a tiny larva deep inside. Gall wasps start out life as an egg laid into plant tissue, which then starts releasing chemicals that induce abnormal growth in the plant. This abnormal tissue protects and feeds the wasp as it develops.

Augochlorini, metallic sweat bees. August, on swamp milkweed. Sweat bees are solitary, unlike honeybees. They apparently can sting, but I have found them to be completely nonaggressive, even less so than a housefly. The tribe Augochlorini contains a number of strikingly iridescent species, such as the one pictured here. I have also seen copper-colored bees of this tribe at the alumroot flowers in my backyard.

*Bombus griseocollis*, brown-belted bumblebee. August, on swamp milkweed. One of a number of bumblebees native to Ohio. While honeybees maintain their populations year-round, bumblebees mostly die off for winter, surviving as a handful of princesses, which will then start their own nests the next year. A side note: I do not know how to tell bumblebee species apart. Apparently it has something to do with the color patterns in the hair on the backs of the bees; perhaps one day I will figure it out. Identifications of these bumblebees were provided by iNaturalist users.

*Bombus impatiens*, eastern bumblebee. August, on rough blazing-star. The only time I have found bumblebees to be aggressive is when approaching a nest, which they construct underground. Even then, they give plenty of warnings, and leave plenty of time to get away. There was a large nest at the nursery this year, and the bumblebees therein only started getting upset when one of us was practically on top of the entrance – within a foot or two.

*Amphibolips quercusjuglans*, acorn plum gall wasp. September, on red oak. This species forms galls on the cups of the acorns, but these galls are often not seen until they drop to the ground, as was the case here. Galls are not only formed by wasps. Three families of fly, four clades of true bug, weevils, and some moths are among the insect gallmakers. Mites, fungi, bacteria, viruses, and nematodes can also induce galls.

Thanks for learning about bees and wasps with me! I hope you have gained an appreciation of our diverse friends. Happy exploring!

M Onion

Nursery Plant Propagator Grower

M Onion joined HF&G Nursery in May of 2022 as our propagator. She completed her bachelor's degree in Botany at Kent State University the same year. While at Kent, M worked in their display greenhouses, growing and caring for plants. M has a strong interest in and knowledge of plants, especially native species.

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