If it Weren't for Natural Control We'd be Swimming in Bugs!
Insects can reproduce very quickly. Let's take for example the common housefly. These flies can complete a generation (egg to larva to pupa to adult) in less than two weeks under ideal conditions and produce approximately 300 young per female. Theoretically, if you started with two flies (male and female) under ideal conditions, after one generation you would have 300 flies, and each female would produce 300 offspring. After only two generations you would have 90,000 flies that in turn would produce 6.8 million offspring, etc. If this continued for just nine generations (approximately four months), there would be enough flies to cover the entire land surface of the United States three feet deep in flies. This never happens, of course, because populations of flies, like other insects, are kept in check by natural control.
The economic value of natural control is huge. In the United States each year, the value of natural control of native insect pests attributable to predatory and parasitic insects has been estimated at $4.49 billion (Losey and Vaughan 2006). This is an often overlooked, free benefit from beneficial insects.How Does Natural Control Happen?
Natural control refers to the maintenance of insect populations within certain bounds by environmental conditions, or factors. Both non-biological and biological factors contribute to the natural control of insects. These include:- Physical factors such as weather (e.g. cold winters can reduce some insect populations).
- Quality and quantity of available food.
- Competition between species or among individuals of the same species.
- Amount and quality of living space or territory.
- Natural enemies such as predators and parasites.
