This summer around August or September I noticed about 1500 ladybugs crawling on the back (west) side of my house. They were everywhere, crawling around windows, up the walls, etc. I was a bit taken aback, but I figured at the time that it may simply have been a cyclical event akin to locusts and other insects..... The rest of the long-winded question
Here’s the answer according to BUGMAN:
Okay, now here's MY more long-winded answer!
This is a GREAT question. I mean, we have dealt with this ladybug question before, but this might be the most though-out and well-put question we've had at the Ask P.R. Mantis pages! You have done some interesting hypothesizing based on your observations of natural phenomena! Winnie the Pooh would be proud! (see "In Which Pooh Invents a New Game and Eeyore Joins In" pg 92, House at Pooh Corner - it is brilliant!)
Ladybugs (more appropriately called Lady Bird Beetles) are one of the insects who overwinter as adults. Get this -- they gather in huge congregations of adult beetles at or near the tops of hills. They go to high ground in case there is a big thaw and the threat of mass drowning. They gather under the leaf litter, or, more typically, under a light colored rock (that would develop warm surfaces on sunny days, but would remain cool enough so the animals would not be really active and waste their fat reserves) or bark.
This behavior is as much a response to a lack of food as to the cold temperatures in Connecticut winters. Ladybugs eat aphids primarily, and these soft-bodied insects cannot handle hard temperatures at all. They have their own overwintering behaviors and long before the first frost, they have already laid eggs and died. Since the ladybugs don't have any food around, they go into a sort of diapause (a suspension in their life cycle) - many moths do this with their cocoon and many other insects do it with their eggs or larvae - ladybugs suspend their adult egg laying. When there is no food, they stay relatively quiet and save food reserves.
So, what does this mean for your problem? Based on the depth of thought in your question, you've probably already figured out most of what I'm about to tell you.... see how close this is!
I'm going to guess you painted your house white, or a light gray color. I'm going to guess that your house is on relatively high ground. I'm going to guess that you actually started seeing them on your house in the late summer/early fall.
If all this is true, it is clear what it means ("If you think I think the poison is in my glass, you think you might trick me into thinking the poison really is in your glass when in fact I know it cannot be in your glass because...." um.... did you see The Princess Bride? If not, you should!)
You saw huge numbers of them aggregating at their overwintering site - your house! They then found places to relax for the winter, probably under the wall shingles you mentioned and in any wall voids they could access. So during the winter months - especially during the incredibly warm winter we're having in New England this year (their activity level is a function of temperature), you might see them every so often when they come out to stretch their legs.
If we are convinced so far that this is all true, we can also figure that they are not doing any damage - your house is not made of aphids! And they aren't even pooping much and making a mess. They're just hangin' out. We can also suppose you will see a similarly large migration out of your house in the spring!
But there's even more to this fascinating (it is fascinating, isn't it?) story! There is a new ladybug in town. The "multicolored Asian lady beetle" (Harmonia axyridis), is a recent immigrant into our part of the world. it seems to (for some reason) prefer the warm confines of people's houses to the cold leaf litter in the forests of Connecticut!
Many people find these beetles bothersome when they infested their houses. They mostly vacuum them and put them back outside. Perhaps those bugs learned that is not a friendly site in the neighborhood. They didn't come back and that person didn't complain again (or knew what to do without calling again). People like us, who think it's cool and don't feel a need to discourage it might never call. So, it's hard to say without a real study whether they are surviving poorly, if they are finding other sites, or if people are just used to it and not reporting them.
So, as opposed to calling out your local militia, I suggest you buy lots of film for your camera - it's gonna be an awesome spring!!
Well, I hope that helped and was sufficiently long-winded for you!
And thanks again for Askin' P.R. Mantis and BUGMAN