Ahh, springtime, when the flowers begin to bloom, the air warms up, and the sun seems to shine a little brighter. But, wait, what is that ginormous thing hovering in front of me like it is plotting an attack? That would be the male carpenter bee, more curious about you moving about than anything else. One might think of these large bees as giant pains in the… However, to humans, these bees are not much more than an annoyance. Carpenter bees can present some economic impact to wooden structures, and a few females can sting, but they rarely do. Most of what we encounter when an “aggressive” carpenter bee does a fly-by, are male bees trying to figure out what we are. So, what is the purpose of a carpenter bee anyhow? Are they dangerous? What can we do to prevent carpenter bees? Most importantly, how can one get rid of them if we find them boring into the eaves of our homes?
Carpenter Bees in Florida
Here in Florida, there are four total species of carpenter bees and one subspecies. Two each from the genus Xylocopa and Ceratina. The former is generally referred to as large carpenter bees and the latter, small carpenter bees. The subfamily of large carpenter bees (Xylocopa virginica krombeini) is restricted to the areas South of Lake and Sumter counties extending as far south as Dade county. The common names for both large and small carpenter bees come from where they build their nesting sites. Large carpenter bees, of the xylocopa genus, bore holes to create nesting corridors in solid wood such as stumps, dead branches, or logs. Small carpenter bees create tunnels in the stems of softer plants and bushes. The easiest way to tell these two groups of carpenter bees apart is by their size. Those in the ceratina genus fall under eight millimeters in size. In contrast, the larger genus, xylocopa, are those larger than twenty millimeters in size.
Some carpenter bees are similar in size and coloration to that of bumblebees. However, carpenter bees can occur in a variety of colors. Ceratina cockerelli is the smallest of the carpenters found in Florida, measuring just three to four and a half millimeters in length. These bees are entirely black in color. Ceratina dupla floridanus is metallic blue and measures about six to eight millimeters in length. Both larger species xylocopa micans, xylocopa virginica, and the subspecies xylocopa virginica krombeini are often mistaken for bumblebees. These larger species come in a multitude of colors from nearly all black to yellow and black, metallic blues and greens, and even some in a purplish hue. Those who study the bees distinguish between the species by measuring several features. These measurements include the width between the eyes, the number of antennae, and the type of mandible the bee possesses. Something the rest of us may not want to get up close and personal to inspect.
Are carpenter bees dangerous?
Carpenter bees are far from dangerous to humans. While many people run screaming at the sight of any bees, the carpenter does not usually sting. Males do not even have stingers, and unless a female is threatened and you are close to a nest, she will not likely sting. The most damage that carpenter bees do is to your wood furnishings and structures. Females spend a lot of time boring out holes to lay eggs in. These females will return year after year to the same site. They prefer to dig tunnels into unfinished or unvarnished wood. Many times, homeowners will find carpenter bee nesting sites on the underside of eaves where it is often left unpainted. Replacing with pressure or chemically treated wood will discourage bees from building nests in these areas. Another place one commonly finds carpenter bee nests is in children’s play equipment and wooden patio furnishings. Choosing pressure-treated, chemically treated, or painted options in wood furnishings will prevent carpenter bees from seeking nesting sites in these areas.
Carpenter bee damage
Carpenter bee’s economic impact comes when they bore into the eaves of the home or other wood structures and cause structural instability. There are a few tell-tale signs that carpenter bees leave, which will help you identify whether you have a nest. The most obvious tell-tale sign of carpenter bees is finding small dime-sized holes. Look for these in unpainted or unvarnished surfaces such as those previously mentioned. If you see piles of sawdust, then you know that there are females actively chewing through your wood to create a nest. Once they have made a home, it is difficult to rid yourself of them without treatment, because the females will return to a nesting site year after year. Finally, if you find streaks of yellowish-brown splatter on the side of your home, especially under the eaves, then again, you know you have carpenter bees. This icky sludge is bee poo and can be quite challenging to remove from the side of your home.
Why are carpenter bees aggressive?
Carpenter bees are not really aggressive. The males will swoop and attack if a human comes too close to a nesting site. However, the males do not sting as they do not possess stingers. Females, on the other hand, are capable of stinging, but rarely do unless threatened. You may see carpenter bees hovering in an area. This characteristic is both part of their mating ritual and protective nature. Males will “hang-out” and wait for the females to finish building the nest and lay their eggs and will then patrol the area where the nest has been created. If you see a carpenter bee hovering, the best way to get it to leave you alone is to throw a small object in the opposite direction. These bees are attracted to anything moving and can easily be distracted by giving them another moving object to chase. The males can appear to be aggressive when they dive-bomb and swoosh by moving humans. Again, this is not so much a militant attack, but rather curiosity about you and their protection of a nearby nest.
How to get rid of carpenter bees
Carpenter bees, like all bees, are pollinators, so getting rid of them may not be in the best interests of your garden. However, as previously mentioned, they can cause structural damage with their drilling nature. The smaller carpenter bees do not tend to nest in human furnishings and structures, but rather pithy plants and bushes. So, if you do not find the tell-tale holes in wooden structures, then you likely don’t have large carpenter bees. If you do have the nesting holes, the best way to rid yourself of the problem is to use insecticides aimed at bees and wasps. Aerosol varieties tend to work best to penetrate deeply into the nests. However, you can also use powders, dust, or other encapsulated methods as well. A liberal application should be sprayed into the holes and left to sit. After several days, fill the holes with the putty or other wood filler to expose the females to the pesticides.
To prevent the bees from returning, if you have unpainted or unfinished wood surfaces, try painting or staining them as carpenters prefer natural wood to drill in. Large woodpiles are also an attractant for carpenter bees of both small and large varieties. Make sure to keep your yard debris-free, and you’ll spend less time this summer dodging the fly-by of a carpenter bee.
Tips for dealing with Carpenter Bees
Despite their dive-bombing us as we try to enjoy the back deck, carpenter bees are one of the least problematic pests out there. Yes, creating nests in our eaves, children’s play sets, decks, and other wood structures is a pain and can cause structural instability. However, the most annoying thing about carpenter bees is dodging the scout males. But overall, of any pest, the carpenter is the last on the list to worry about, and one of the easiest to discourage. Merely painting or otherwise finishing your wooden structures will all but exclude these rotund bees from taking up residence in the first place.
US Forest Service