think twice before you swat a fly or squash a bug: a new study says insects contribute more than $57 billion (euro47 billion) a year to the u.s. economy.

　　think twice before you swat a fly or squash a bug: a new study says insects contribute more than $57 billion (euro47 billion) a year to the u.s. economy.

　　and that is a very conservative estimate, said john losey, a cornell university associate professor of entomology who conducted the study, published in the current issue of the journal bioscience.

　　"most insects tirelessly perform functions that improve our environment and lives in ways that scientists are only beginning to understand,`` said losey, who wrote the study with mace vaughan of the portland, oregon-based xerces society for invertebrate conservation.

　　there are more than 1 million named insect species _ and probably an equal number unidentified _ making them the most abundant life form on the planet.

　　the study focused on four particular services that bugs provide, and what the cost would be if the insects were gone:

　　nutrition for wildlife. the researchers looked at how much is spent annually on observing or hunting wildlife, and how much these animals depend on insects for food. value: $50 billion (euro41.3 billion).

　　pest control. insects often prey on other insects. the researchers looked at the amount of damage done by pests, and the losses that would result if their predators disappeared. value: $4.5 billion (euro3.7 billion).

　　pollination. the researchers looked at the value of crops that are insect-pollinated (not including crops pollinated by domesticated honeybees). value: $3 billion (euro2.5 billion).