EA - If Adult Insects Matter, How Much Do Juveniles Matter? by Bob Fischer

Link to original articleWelcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: If Adult Insects Matter, How Much Do Juveniles Matter?, published by Bob Fischer on February 6, 2023 on The Effective Altruism Forum.Key TakeawaysThere are major uncertainties about sentience, welfare ranges, and the taxa of interest that make it difficult to draw any firm conclusions.Nevertheless, it’s plausible that there are some differences in the probability of sentience and welfare ranges across insect life stages. However likely it is that adult insects are sentient, it's less likely that juveniles are sentient; however much welfare adult insects can realize, juveniles can probably realize less.These differences are probably best explained by the life requirements at those stages, which vary in species-specific ways.Insofar as we can compare the magnitudes of these differences, the best evidence currently available doesn’t support the conclusion that they’re large. For instance, we don't see a plausible argument for the view that adult insects matter 1,000x more than juveniles.We may be able to make some predictions about the probability of sentience based on two factors: first, degrees of independence at the immature life stages; second, the developmentally-relevant details of the rearing environments.IntroductionThis is the ninth and final post in the Moral Weight Project Sequence. The aim of the sequence is to provide an overview of the research that Rethink Priorities conducted between May 2021 and October 2022 on interspecific cause prioritization—i.e., making resource allocation decisions across species.The goal of this post is to help animal welfare grantmakers assess the relative value of improvements to the lives of some commercially-important insects: the yellow mealworm (Tenebrio molitor), black soldier fly (Hermetia illucens), western honey bee (Apis mellifera), house cricket (Acheta domesticus), and silkworm (Bombyx mori). The vast majority of yellow mealworms, black soldier flies, and silkworms do not reach adulthood in the commercial systems of interest here (the exceptions are the members of the breeding population). By contrast, honey bees and house crickets do reach adulthood. This raises the question of how to value improvements to the lives of insects in their immature versus adult life stages. If adult insects are more likely to be sentient than immature insects, then, all else equal, it’s more important to prevent harm to adult insects than immature insects.Similarly, if it’s likely that adult insects can suffer more intensely than immature insects (which is relevant to their respective welfare ranges, which are one dimension of their respective capacities for welfare), then, all else equal, it’s more important to prevent harm to adult insects than immature insects. So, insofar as it’s possible to identify differences in either the probability of sentience or welfare ranges, that information is action-relevant when all else is equal. And insofar as we can compare the magnitudes of any such differences, that information may be action-relevant when all else isn’t equal.This document unfolds as follows. In the next section, we provide some relevant biological information about the taxa of interest and introduce the reader to some important dimensions of the development and neurobiology of insects. After that, we explain how Rethink Priorities tried to estimate differences in the probability of sentience and welfare ranges for other taxa—which, among other things, involves surveying the literature for evidence regarding sentience- and welfare-range-relevant traits. We extend that approach here. Then, we summarize the literature we reviewed. Next, we argue for the key takeaways. Finally, we make some suggestions regarding future work in this area.Biological Background InformationInsects develop in the larval (or nymphal) stage, un...