This doesn't really explain human extinction. Our food supply doesn't come from a natural ecosystem.
- Commercial bee populations aren't declining. (There has been an increase in Colony Collapse Disorder, but lost colonies are replaced and total bee population hasn't declined.)
- The vast majority of the world's food supply does not depend on pollination from insects. To quote from https://en.wikipedia.org/wiki/List_of_crop_plants_pollinated...:
> The most essential staple food crops on the planet, like corn, wheat, rice, soybeans and sorghum, need no insect help at all; they are wind-pollinated or self-pollinating. Other staple food crops, like bananas and plantains, are sterile and propagated from cuttings, requiring no pollination of any form, ever.
- None of the crops that require pollination from insects are essential to human survival. It's hard to see how their loss could lead to our extinction.
- Crops can be pollinated by hand or machine.
- Crops can be propagated without seeds.
- Crops can be grown in all kinds of unbelievable conditions. Crops can be grown without soil. They can be grown in space stations, completely isolated from Earth's ecosystems.
- Extinction is a very strong claim. To support it, it wouldn't be enough, for example, to show that 90% of the population would die off, leaving 750 million people. They need to propose a mechanism by which all humans would die.