I couldn't agree more. I'm vegan for only 6 years now and already convinced several people to go either vegetarian, almost vegan or reduce their meat consumption. (No total victory yet, unfortunately) It also enabled me to have literally hundreds of deep talks about animal suffering. People listen to people who are close to them. You are in an unique postion to influence your very own social circle and you shouldn't let it pass if you are truly commited in doing the most good. 

I totally agree with your conclusion. I like to read your posts and I'm sorry for derailing this one. I was just genuinly surprised anyone would assume that one single second of any pain could be "as bad as losing 24 h of fully healthy life."

"I speculate birds cause 1 s of excruciating pain to each arthropod they eat. So I estimate the decrease in the welfare of each arthropod is equal to that from them losing 24 h of fully healthy life" 

Did you just equal 1 second of suffering to a whole day of good life? 

I like Peter Godfrey-Smiths concept of a life worth living and the thought experiments that come with it. So basically you get to decide if you want to be reborn and live the life of certain animal or not. If you say you would take the chance to live a certain life, you consider this to be a life worth living. So in this case it would be like living a perfect day in insect form and in the end I get eaten. The pain is intense but since it's only one second I will hardly notice it. 

Or I get the chance of living a full 2 good months in insect form and in the end I live through a very painful one minute fight for life and death that I lose. For me both examples are not even remotely close calls but if they are close calls for you than negative utilitarism makes intuitively sense to you, while I don't get it. To be honest if you give me the chance to live just through the fight I would still take it cause it's exciting and if I don't take it, there is nothing.

This whole concept that whole species might have net negative lifes has some arbitrariness to it. If some people feel that 1 second of excruciating pain is worth 24 hours of living while others think it's not a big deal you can just type in any numbers in your calculations in order to get the result you want. It would be interesting to set up similar thought experiments and ask people in war zones or tribal communities how they feel about those things. They definitely know more about pain and the struggle to survive than we do.

I do think that insects are extremely important. I am, however, very surprised that you believe insects have net negative lives and that you seem to suggest that reducing their numbers is actually good for them. My intuition has always been that they live fairly good lives. Honeybees, for example seem to enjoy some of the things we enjoy like searching for food, eating it, telling their friends about their findings, building things, sitting in the sun, cuddling together, sleeping, dreaming etc. They also experience things we can only imagine like flying and 360° vision.  What they don’t seem to experience are certain forms of bodily pain caused by injury due to their exoskeleton and the negative feelings that come with overthinking things. (All of this is very speculative of course)

For the moment we just can’t know which intuition is right and with about 1 million insect species we might expect to find the whole range. Species that live very good lives, those that have very bad ones and those that aren’t sentient at all. On the edge of sentience there might even be animals that can experience only joy or only suffering.

So, what would be the best course of action in light of uncertainty?

I would argue that 

1. research on insect welfare should be our top priority.

and

1. until more data is in, we should protect rather than decimate insects because of the asymmetrical risk involved. If we drive the happiest species in the world into extinction it would be hard to overestimate the amount of joy, we would have destroyed. If on the other hand your view is right we could still decimate populations once we know that this is a good thing. Furthermore, at this point there just is no way to reduce populations without causing unimaginable harm. (Unless insects aren’t sentient, of course.)

I’m fairly new to the topic of insect welfare, so please point out if I made any logical errors and recommendations for good research projects are always welcome.