Like most hive pests, including wax moths and hive beetles, ants are opportunists. Ants in your beehive may be a sign of other problems because a strong colony that is both populous and healthy can generally keep them away.
Most ant species are a mere annoyance in the hive. They often raise their young in the space between the inner cover and the telescoping lid, or sometimes in the small space between the telescoping lid and the outside of the hive where it is warm, damp, and relatively safe from bees.
Up here in the Pacific Northwest I have encountered hundreds of white “eggs”—which are actually pupae—attached to these protected surfaces. I simply skim them away with my hive tool, a five-second fix.
However, if you see ants actually traveling into the colony itself, you need to do a hive inspection. Remember, ants are opportunists and scavengers. A weakly-defended hive is an opportunity for easy pickings, so a procession of ants leading into the hive interior may signal that something else is wrong with your colony. Open it up and find out.
Weak and failing hives are not the only ones to attract ants. New packages, small nucs, newly captured swarms, and recent splits may not have the bee-power they need to defend against ants. Keep a close watch on these small colonies.
Argentine ants are the aggressive exception
The widespread invasion of Argentine ants into many parts of the world, including southern areas of the United States, has caused trouble for beekeepers. If you live in an area invaded by Argentine ants, more than passive control may be necessary. Stories abound of large colonies absconding to get away from invading hordes of Argentine ants.
The Argentine ants live in enormous colonies that spread into neighboring areas when a queen walks off and founds another closely-related colony. Sometimes these close-knit colonies even share workers, so rather than fighting and competing, they form vast genetically-similar networks which out-compete local species.
These amazing invaders are very small, averaging about 2 mm long. As such, even tiny spaces between brood boxes provide ample space for coming and going. They normally walk from place to place and can be seen in long columns. The ant population within a colony varies with the season, but in North American they peak in October.
Although they are omnivores, Argentine ants have a preference for sweet foods, which means they are highly attracted to beehives. All that luscious food packed into one small place with easy access is irresistible.
Getting rid of those pesky ants
The safest way to remove ants from a beehive is to use some form of mechanical separation. Why? Because both ants and bees are in the order Hymenoptera. Ants are much more closely related to bees than are wax moths (order Lepidoptera), small hive beetles, (order Coleoptera) or Varroa mites (which are not even insects, but arachnids). The closer things are related, the harder it is to separate them with chemical means.
How to prevent ants from invading your hive
- Be proactive: You can do several things to protect your hives from ant invasions. Since Argentine ants are walkers not fliers, hive placement is important.
- Keep your hives off the ground: Ants live in the ground, so any hive sitting on the ground is easy pickings. In addition, when a hive is on the ground it is difficult to see them entering. A stand with six-inch legs will work for ants, but longer legs will provide some protection from skunks, opossum, and raccoons as well.
- Monitor the legs of your hive stand: To get to your hive the ants have to walk, so take a peek at the legs of your hive stand whenever you can. Remember, Argentine ants are small, so you need to look closely.
- Remove bridges: Anything that bridges between the ground and the hive can quickly become an ant highway. Look for branches, tall weeds, blades of grass, and wildflowers that may grow beneath your hive stand.
- Repair your boxes: Yes, it’s hard to keep all our bee boxes in tip-top shape, but obvious cracks can be filled or repaired, joints can be tightened, and irregular edges can be sanded or planed. If it sounds like a lot of work, it is. But it’s far better to mend a box than to lose an entire colony to ants.
- Carry a bucket: When working your hives, toss pieces of burr comb and other hive debris into a bucket. If left on the ground, these seemingly insignificant morsels can attract ants (and other pests) from far and wide.
- Build an oil barrier: Probably the most effective defense against the Argentine ant is maintaining a pool of vegetable oil around each leg of your hive stand. Many beekeepers simply set each leg of the stand into an oil-filled tunafish can. Others fill the cans with a solution of soapy water. Soap, a surfactant, causes the ant to drown.
Other methods that work for some
If the oil-filled can isn’t to your liking, or if you have some less pernicious type of ant in your area, here is a list of some anti-ant protocols from my readers. The original comments explaining these ideas are attached to the post, “Bad ant advice and the ascension of bees” written back in 2012.
The methods listed worked for some beekeepers, but not for others. I haven’t tried any of them because I simply scrape the ants away, but the comments are interesting to read. Ideas include:
- Ground cinnamon sprinkled anywhere ants might go
- Commercial ant powder dusted on the legs of the hive stand
- Diatomaceous earth sprinkled on the ground around hive stand
- Tanglefoot smeared on the legs or on an upside down pie pan
- Borate in sugar solution
- Ground tansy (Tanacetum vulare)
- Vaseline on the legs
- Wood ash piled around the base of the legs
- Heavy grease smeared on legs
- Cornmeal sprinkled on the ground
In any case, don’t jump to conclusions about ants. Remember, if you open a dead-out or the hive of an absconded colony, the presence of ants doesn’t mean the ants caused the problem. Like hive beetles, wax moths, wasps, and earwigs, ants frequently move into an empty hive to partake of the spoils. The same applies to mold and fungus.
Opening a hive after the colony is gone only tells you what is there now, not what was there before. Just as looters didn’t cause the storm, ants may simply be taking what is no longer guarded.
Honey Bee Suite