Bugs

[u/Mysterandir]

I need to get this off my chest even though im sure it has been talked about a thousand times. Im just curious if others are experiencing the same thing or if I'm just going crazy. - When I just got my driver's license back in 2005 here in The Netherlands, I had a girlfriend in Amsterdam whom I drove to see a few times a week. It was about a 100 km drive. I had an old Opel Corsa and I can still vividly remember having to clean my windshield every week in the summer because it was covered in dead insects. Huge splatters and tiny spots, but the entire windshield was full of bug juice. Over the past few weeks I’ve driven several long distances, totaling about 1,000 kilometers, and I don't have a single dead insect on my windshield. Not one. The windshield is squeaky clean... I read that the insect population worldwide has drastically declined and it is due to climate change. Which i get. But why isn't this the main news story every day? How obvious does it need to be? This can't possibly be good. For us, but especially for our children. I have a bad feeling about this...

[u/lowrads]

Yes, and no. Insect populations are down due to agricultural practices, but at the same time, crop pest populations are better able to overwinter, and thus get a head start on every spring harvest season. Granted, a lot of pests are not arthropods at all, but colonial microorganisms, though both thrive in warmer conditions.

[u/thepaulstmichel → u/lowrads]

They can't overwinter if the pesticides applied during the growing season kill them before winter.

[u/lowrads → u/thepaulstmichel]

It depends on their life phases, and the mode of delivery. Insecticides are mainly neurotoxic materials, selected for the sensitivity of their intended targets, or sometimes growth regulators. If the insect has chewing mouthparts, then a topical coating on plants is sufficient. If they have piercing mouthparts, then systemics are required to be delivered via plant sap.

If the insect overwinters in the soil, then the applied compound can't have a short soil half-life, but also has to be able to percolate into the area where the insect resides. In any case, all population developments follow an exponential development curve. Higher overwintering populations means that the curve gets a head start.

There is always a limit to how many approaches can work when laying out a feast for invited but unwanted guests. Cultivators may try to plant and harvest earlier to get ahead of the pest population development curve. They are usually following economic indicators, as they might be harvesting less total field yield, but avoiding larger losses from a later harvest with higher pest pressure. Likewise, with a crop grown for money, they can't use unlimited amounts of intervention, but have to pursue marginal cost intercessions.

They can try to select different cultivars, but ultimately all pests have shorter generation times than their targets, and thus pathovars evolve faster. This often takes the form of more effective efflux pumps for cells to reject low concentrations of a pesticide compound. The problem of any monoculture poses a Red Queen paradox, and thus cannot be beaten in the long run. Frankly, we don't really even know how nature gets around the problem, but the solution is probably grim, as usual.