Publication Alert: Can farmed insect welfare be assessed physiologically?

Review: Exploring correctness, usefulness, and feasibility of potential physiological operational welfare indicators for farmed insects to establish research priorities (Johnson and Barrett 2025; animal)

Acknowledgement of Funding and Conflicts of Interest: Rethink Priorities (EIN 84-3896318) provided funding to MB and MGJ for the researching, writing, and/or editing of this work.

We farm trillions of insects, and are poised to farm many trillions more (Shah and McKay 2025). How can we know what is good or bad for the welfare of these insects on farms? Could their neural, endocrine, respiratory, or immune systems give us clues? What about whole-body indicators of health or condition? In this paper, Meredith Johnson and myself set out to review insects’ physiological systems and what they might tell us about stress, health, and insect welfare on farms.

Figure from Shah and McKay (2025), *Rethink Priorities,* projections of farmed animal numbers in 2033, in billions. Projections suggest that insects will make up the vast majority of farmed animals in the future - and are the majority of farmed animals now.

Insect welfare is a nascent field, so not much is known about what indicators are actually valid for understanding when insects are doing well or poorly from a welfare perspective. We thus use this review to discuss which physiological indicators tend to be useful in assessing farmed vertebrate welfare, and draw connections between vertebrate and insect systems to try and determine if those indicators might be useful in insects. Many people may be surprised that there are parallels in the stress physiology and neuromodulation of insects and mammals! So, some (though certainly not all) vertebrate indicators might serve as starting points for understanding how to assess insect welfare.

An example of stress pathways in insects and mammals, and their potential relationship to welfare state (adapted from Cinel et al. 2020)

We end by prioritizing a list of indicators that should be explored for potential validation in insects because they are either highly likely to be correct, highly likely to be feasible to assess on farms, or (in the best cases!) both (Table below).