Friday, January 05, 2007

How fast can bedbugs multiply? - Part 2

Last time we reached a conclusion that it would take only a few months to have a heavy infestation, today we'll see how the infestation can be control by limiting the food supply.

First of all, here's some background information:

Male bedbugs need to feed before mating

Female bedbugs need to feed before laying eggs

There are five nymphal stages, and at least one blood meal is required for each nymphal stage for the nymphs to molt successfully

Therefore, a total of seven blood meals are required to create an adult bedbug. You may argue that the male might mate multiple times and the female might lay a few eggs after each meal. This may be true. However, nymphs feed a lot more frequently than once every nymphal stage, and the adults need to feed just to survive. Therefore, 7 meals are actually very conservative estimate. Let's assume all meals follow the "breakfast, lunch, dinner" pattern of three bites, then, to generate a new adult bedbug, they will have to bite you at least 21 times.

Now let's assume that you get bitten three times a day (That's a lot of bites considering that you have effectively protected yourself). You will have 21 bites per week, just enough to generate a new adult bedbug. In three months, you will have 14 bedbugs, including the original 2. Remember without limiting the food supply, the number reached 1000 in three months? That's 14 versus 1000, what a difference? Also, after 10 months, some bedbugs will start to die, since the growth is linear, whenever a new bedbug is created, another one will die, and the population will stop to grow.

If you have successfully isolated your bed and living areas, you shouldn't get any bites at all.

Bedbugs cause problem because they bite us, but this also makes them vulnerable since they rely too much on our blood. By protecting ourselves, we can effectively eliminate their food supply, break their reproductive cycle, and make them more vulnerable to insecticides (due to lack of nutrition).

You might be advised not to isolate your bed for two reasons:

1. If the blood meal isn't available, the bedbugs might spread to other rooms.

2. Some pest control companies want you to use yourself as the bait, and lure the bedbugs to cross the insecticides and get killed.

The first reason does not make too much sense to me. It's too big a price to pay to feed them with your blood and let the population grow just so they won't spread to other rooms. Caulking is an effective way to prevent them from spreading by the way.

As for the second reason, the strategy sounds good and might be working at this point. But there are questions you need to ask yourself and things you need to consider:

1. Are you mentally strong enough to commit to this kind of strategy?

2. Bedbugs may not take the bait. Behavioral resistance is common among insects. Insects developed this mechanism will simply stop feeding to avoid insecticides.

3. Pyrethroid resistance has already been reported and is becoming more widespread, according to a report by the University of Kentucky. The more frequently the same class of pesticides is applied, the quicker resistance will develop, and I believe this is the case with pyrethroid-based insecticides right now. As the bedbug epidemic becomes widespread, resistance will become widespread as well, especially because most people including many PCOs still equate pest control to chemical control.

I have spent lots of efforts on "Why and how to protect yourself" so far. A member of our Yahoo Bedbugger Group suggested me to put more emphasis on the topic, and I also thought it was important, since "eliminating the food supply" is an essential part of Integrated Pest Management, a concept that my whole strategy is based upon.


Anonymous Anonymous said...

I have just found out I have bed bugs, I just move into my new apartment and found at least 10-15 dead and 5 adults. Once I realzied what they were I trash my box spring and throw out 80 percent of my sheets, the I vacumed and washed most of my clothes. I thought I solved the issue untill two weeks later I found one that just feed on me and another near my bed on the floor, anyways I read alot about bed bugs and cant figure out where the nest is and is there any way I can kill off the few that are left before they spread. And thanks to your spread sheet I have a really good idea on how long and how about these little pain in the butts will take.

3:43 PM  

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