Re:Monarch butterfly populations in U.S. west are down an or...
by cryptonector on Sunday December 02, 2018 @12:15AM
(#18580944)
Yeah, but think about it: insect population is down? why keep using pesticides at the same level as usual?? And if you reduce pesticide use because there's fewer insects, and if the insect population recovers, then you'll have some very suggestive evidence (still not dispositive, but so what). There's a hypothesis to test, so let's test it.
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Re:Monarch butterfly populations in U.S. west are down an or...
by eesmith on Sunday December 02, 2018 @01:37AM
(#18581145)
Here are some possible answers to your "why??"
Insect population may be down overall, but not down with crop pests.
Insecticides may require a certain density of use to be effective; that is, there may be a non-linear dose/response curve such that it's not really meaningful to reduce the current levels.
The goal is to maximize income. Reduced insecticide use, even with the relatively low corresponding insect populations, might still reduce the yield and/or quality and therefore profit. Think of how the oceans are overfished, but while there's a good reason that everyone should greatly reduce their catch, there's no good reason for any one fishing crew to do that on their own.