beekeeping equipment

Many dead bees on screened inner cover: what happened?

A beekeeper asks: “Why are there so many dead bees on my screened inner covers?” Good question.

I can’t be certain without doing an experiment, but I believe most of the dead bees on your screened inner covers are robbers that died trying to get into the hive. Remember that robbers don’t know where the hive entrance is. Instead, they follow the scent. If the scent of honey is drafting out of the top of your hive—especially during a late summer nectar dearth—robbing bees are going to pick up that scent and try to get in at that point.

Both robbers and yellowjackets follow the scent

This is similar to the bees that follow the odor of honey that comes from my kitchen every autumn when I make barbecue sauce. The fan is ducted from my stove hood, through the attic, and comes out at the other end of the house. When I cook anything with honey—and the barbecue sauce contains a lot—the bees form a cloud where the air exits the duct.

Sort through the dead bees and see what you find. Mine are always mixed with yellowjackets—another indication that robbers are looking for a way in. Yellowjackets and other wasps do the same thing—they follow the scent to find the source. And once bees start dying up there on the screen, the yellowjackets are even more interested. I’ve also found other things on the screens, including wax moths, spiders, and various beetles.

Shim placement may keep bees from the screened inner cover

However, it is very possible that some of the dead bees on the screened inner cover were residents of your own hive that couldn’t find their own entrance. This would be especially true of first-time foragers or bees out for an orientation flight.

For this reason, I think it is best that the shims for your screened covers are in the front and back so that the smell wafts out the sides. If the shims are on the sides, the smell comes out of the front and back. Hive smell coming from the front is probably more confusing to the residents and more advantageous to the robbers since it is closer to the real hive entrance.

Good ventilation can be a trade-off

Some of my screened inner covers have shims on the sides, and some have shims on the back and front. I’ve never noticed a correlation between dead bees on a screened inner cover and the location of the shims, but now that I’ve thought about it, I will definitely look for that in the future. In the meantime, don’t worry about the dead ones. The excellent ventilation provided by screened covers is more important than a few bee losses . . . and most probably those bees came from somewhere else.

Honey Bee Suite

The dead bees on a screened inner cover may have been robber bees searching for a way into the hive.
A screened inner cover lets the scent shine through. This one has shims on the sides.


  • Forgive my ignorance here, but did I read this right that you have a screened cover on the tops of your hives? I’ve got both solid bottom and screened bottom boards, but my top board is just an oval shaped hole, with the center-notch to offer an alternative entrance/exit.

    Looking at the picture of your screen, the screened area is much larger than the screened area of my bottom board further leaving me to wonder if I’m learning something new here or just confused.

    Add to this while I’m on the topic of screened bottom boards, I’ve been told that the screen goes to the top so from the bee’s perspective, it’s a smooth transition from the screen to the wood. Their reason for this orientation is to make it easier for live bees to haul out trash and dead bees. When the screen is on the bottom, they have to lift the debris from the screen, above the wood, to get it out. And what can happen is debris just fills up on top of the screen particularly at the back of the hive. I don’t know this to be true or not, so I’m not trying to defend this as the proper way. I am asking if there’s any truth to this and their explanation.

    • cgrey8,

      1. The screened inner cover replaces the regular inner cover (the one with the hole in it) during the summer. This provides good air flow in the hive: in through the bottom screen, out through the top screen.

      2. I would agree that the screened side of the bottom board should face up. Not a big deal, but is probably easier for the bees to do their housecleaning.

  • Hallo Rusty,
    This is a very good explanation and it sounds a useful item to use in the bee hives but I don’t know where to put it when as you recommend in other posts that you use a moisture quilt. I have 1 hive with 2 brood supers, and 2 hives with one brood chamber but the rest is the same. On top of the top there is a wooden inner cover just with one hole of about 10cm/4″diameter. On top of this is an empty honey super for feeding. There is no extra item between this feeding box and the moisture quilt. On top of the moisture quilt fits the telescoping cover. I have the holes covered in insect gauze as you explained in your instruction for them. On top of the wooden of the honey supers used for moister quilts I have added a double row of lolly (popsicle) sticks so that the lid doesn’t sit completely flush on the sides of boxes. Would it be better to use the screened inner cover than the closed one and how do the bees climb up for their food if it is in that same place? (me being dense now) Is there anyway to contrive to make the hole and keep the gauze tight? In this country the bee brood supers and honey supers all sit on a screened bottom very like you have described. It is about 4 inches high. Into this slides a varroa drawer when you want to check for mites otherwise there is ventilation going upwards from the ground. In my case on top of this bottom screen I have the slatted rack construction you advised…. Guess who is an avid reader….. Seems like I almost have a Rusty Burlew Hive….
    Bye for now Lindy

  • What about an upper entrance when using a screened inner cover? Do you use an Imirie shim with a slot opening in the front? Or maybe leave out some of the wood strip that holds the screen on?

    I had a thriving colony that was very busy coming and going at the bottom entrance this year, and the screened inner cover at the top for ventilation. I wanted to take advantage of an entrance close to the supe that people have mentioned helping store more honey, so I turned the screened inner cover upside down and put an entrance reducer toward the back. I saw lots of bees on top of the super frames, and some of them peering out the large upper entrance, but don’t think many more were using the upper entrance to come and go than for the typical 1″ wide upper entrance.

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