How to deter harlequin ladybirds in my house and/or hopefully kill them? Do ladybirds build nests?

Question

In my bathroom at home (south UK) we have a real problem with harlequin ladybirds (NOT native to the UK).

Is there any way to prevent them from coming into the house at all (other than polyfilling all the hairline cracks and having windows and doors permanently sealed)?

I'm asking this because I'd like to know how to get rid of them without using thing spoisonous to humans if at all possible.

I'm asking about the nests because one time my brother discovered 30 of them in a clump on the bathroom ceiling. Plus we seem to get those ladybirds in the house most days.

Please help!

Answer 1

Studies at some leading universities have found the best way to control them is to get three tubes of caulk and a caulk gun and go around the house and fill every crack and hole you can find, especially on the south and west sides. It's a lot of work but these Asian ladybugs get between the outer wall of the house and the inner wall. If they find a hole in the inner wall, well, then they are in your house. Once there the best control is a vacuum. If there are quite a few you may want to use a vacuum with a disposable bag. The vacuum beats them around a little and they smell bad.

The beauty of caulk is it works for years and it keeps out a lot of other pests like spiders, ants, millipedes, etc.

You other option is to get a hose-end sprayer and spray the sides of your house with malathion or sevin. This will kill most of them before they can get between the walls. The downside is you have to do it every year. The first year may be an emergency and your only option but do you really want to have to spray your house every year? And who wants to live in a house coated with pesticide?

Go for the caulk. I did it and I had exactly 3 of them show up in my house all last autumn and winter.

And no, they do not build nests. They cluster together because they are all finding the same hole to get into your house so it may appear to be a nest but it is not.

Answer 2

There is no concern with having ladybirds in the home, they are actually harmless. Ladybirds are not pests, and do not eat our food or destroy our property. As a matter of fact they are all predators, well the vast majority anyways, and they have a fondness for many of the pests that surround us, including many deleterious plant pests. Many varieties tend to aggregate in homes or tiny spaces when the weather becomes unfavourable, so if it was cold or raining when you first noticed them then that is probably why they are in your home. During the spring and summer months they prefer to be outside where their food is plentiful. It is possible too that they were already in the home as of last autumn and only began to wake from diapause (hibernation) when you saw them, that would explain why they were in there. Hope this helps!

Answer 3

I don't know the term ladybird bug but can tell you about the harlequin bug. Murgantia histrionica is a plant feeder. It is harmful to cruciferous plants (like cabbage). It does seek shelter in winter and if you have good forage nearby and easy access so they can go out for a bite on a warm winter day, they choose your house.

Since I know of no beneficial purpose, and I know how daunting sealing the entire house can be, I suggest you vacuum them up. I have vacuumed up many insects without them ever escapeing the vacuum.