Insect welfare in farmed, wild, and research contextsUnderstanding and protecting the welfare of insects

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This profile is tailored towards students studying agricultural sciences, biological sciences, philosophy and ethics, and psychology and cognitive sciences, however we expect there to be valuable open research questions that could be pursued by students in other disciplines.

Why is this a pressing problem?

10 quadrillion insects are alive on the planet at any given time, with quadrillions impacted by human management practices (such as neurotoxic pesticide application). Over 1.2 trillion insects are farmed each year in the Insects as Food and Feed (IAFF) industry; by 2030, it is expected that at least 8 trillion insects will be farmed, and the industry will only continue to grow. Billions of insects are used in research labs each year with little focus on their welfare during rearing and experimentation. Insect use and management occurs at a scale rarely seen across the animal taxa; despite this scale, their welfare has largely been neglected.

Data on insect sentience suggests that many groups may plausibly feel pain; evidence is strongest for Diptera (flies, mosquitoes) and Blattodea (cockroaches, termites) at the adult life stage, as each order contains model species for the study of nociception and/or affective disorders. Still, insect sentience is uncertain and more research is needed, particularly on other taxa and life stages. In addition, it is essential to begin the process of discovering and promoting methods of humane treatment in wild, farmed, and research contexts while our knowledge of whether insects feel pain continues to grow.

Explore existing research

If you’re interested in working on this research direction, below are some ideas on what would be valuable to explore further. If you want help refining your research ideas, apply for our coaching!

Research papers

Please also see the ‘Research Library’ of the Insect Welfare Research Society, which catalogs all research articles relevant to insect sentience and welfare.

Other readings

Books

  • Barrett M. “Insects”. 2024. In Clutton E, Musk G (Eds), Pain and Suffering in Farmed Animals. Springer. Birch J, Crump A. 2024. Invertebrate Sentience: Evidence, Ethics, and Policy. Routledge.
  • Carere C, Mathers J (eds). 2019. The Welfare of Invertebrate Animals. Springer.
  • Chittka L. 2023. The Mind of a Bee. Oxford University Press. 
  • Fischer B. 2024. Weighing Animal Welfare. Oxford University Press.
  • Tye M. 2016. Tense Bees and Shell-Shocked Crabs: Are Animals Conscious? Oxford University Press.

Organisations

Find a thesis topic

If you’re interested in working on this research direction, below are some ideas on what would be valuable to explore further. If you want help refining your research ideas, apply for our coaching!

Agricultural and welfare sciences

Currently, Barrett et al. have made reports on the welfare of black soldier fly and yellow mealworms available; each report ends with a list of urgent research questions. Reports on other species are in the works, and researchers interested in other species should thus check the ‘insect welfare’ tab on meghan-barrett.com for any other reports that may have been published since this listing was last updated.

  • Barrett et al. (2022) lays out the following urgent future research directions for the study of farmed black soldier fly welfare:
    • Studies of adult mating, ovipositing, and foraging behaviours in natural vs farmed settings, to better understand the impacts of captivity on adult behaviour.
    • Studies that address the impacts of cage densities on the behaviour and welfare of adults. 
    • Determining the nutritional preferences of adults, and the impacts of different diets on longevity, behaviour, reproduction, and welfare. (A study on this is already underway in a lab, however there would be room for collaborative work; contact Meghan Barrett if you’re interested in researching BSF welfare and adult nutrition and if you want to check in on what work is already being done to avoid overlapping effort.)
    • More controlled studies of the welfare impacts of abiotic variables, nutrition, and their interactive effects on larvae, at the scale typically used by the industry (or expected to be used as the industry grows).
    • Controlled studies on population-level variance in the impacts of abiotic conditions or nutrition.
    • Studies that determine sublethal impacts of handling and abiotic factors on welfare (e.g. looking at stress hormone levels).
    • Studies that identify probable parasites/pathogens associated  with  BSF and their welfare impacts, particularly prior to epizootic disease outbreaks.
    • Studies that address the impacts of low-nutrient-content substrates on lethal and sublethal larval welfare at different rearing scales.
    • Studies that assess the effectiveness of starvation/washing pre-slaughter procedures in reducing product microbial contamination levels of BSFL reared on different substrates (such as manure). If these pre-slaughter procedures are determined to be effective in any particular case, these studies may develop guidelines to minimise larval stress.
    • Studies that determine the pre-slaughter stress caused by each slaughter method, as well as pain experienced during slaughter, and the time each method takes to kill (or knock unconscious) all individual organisms, in order to develop humane SOPs (A study on this is already underway in a lab, however there would be room for collaborative work; contact Meghan Barrett if you’re interested in researching BSF welfare and adult nutrition and if you want to check in on what work is already being done to avoid overlapping effort.).
    • Studies that determine the most humane methods of rendering insects unconscious (e.g. anaesthetics), which may reduce larval suffering prior to death. In addition, the impacts of these processes on the final product should be determined.
  • Barrett et al. (2023) lays out the following urgent future research directions for the study of farmed yellow mealworm welfare:
    • Disease / parasitic agents. It is essential to identify, prevent, and proactively manage potential disease/parasitic agents, including ones present at sublethal levels, for both animal welfare and economic productivity.
    • Cannibalism. Cannibalism is a serious problem in the industry that results in injury, disease, and mortality. It is crucial to have studies that demonstrate how volumetric and aerial stocking density, substrate depth, larval rearing practices, selective breeding, hydration/RH, and nutrition contribute to YML cannibalism.
    • Stocking density. Stocking conditions may contribute to overheating, disease, behavioral restriction, cannibalism, malnutrition through resource competition, and more. Research should carefully tease apart the effects of variables like aerial vs. volumetric density, substrate depth, and the effects of physical contact, heat, consumption of frass, and resource competition, to determine the optimal stocking conditions for YML.
    • Feed efficiency. Because YML live within their feeding substrate, feed efficiency concerns are frequently an argument for higher stocking densities which, in turn, raise welfare concerns. Research is needed to determine if: 1) incorporating inedible substances into the substrate could serve to reduce stocking density while avoiding feed waste; 2) changing crate designs could improve larval dispersal throughout the provided substrate, reducing localized density while again managing feed waste.
    • Larval diets. Several outstanding questions remain for when considering larval nutrition. Further work is needed on the welfare benefits of fats and proteins in the diet, especially whether these components help reduce larval cannibalism. Further, no research has focused on the welfare effects of ‘batch’ or more ‘progressive’ feeding methods for YML or whether overfeeding has negative welfare effects (as has been observed in other larvae). 
    • Mycotoxins. It would be valuable to have studies that assess the welfare impacts of environmental pollutants, particularly natural sources of mycotoxin-contaminated grains, on YML and/or adults. It is especially important to further test high concentrations of grains with multiple toxins present, as early-instar YML may be more sensitive to the toxins.
    • Adult YM. Adult YM welfare is particularly understudied. Researchers should prioritize inquiry into optimal diets (including the possibility of adult protein limitation under current conditions), stocking densities, and abiotic conditions, as well as threat vectors such as diseases and parasites.
    • Slaughter and depopulation. Very little is known about the humaneness (intensity of pain × time to death, where less is better) of YM slaughter and depopulation methods under different standard operating procedures. For instance, freezing in air is used to cull adult YM and slaughter YML. However, the welfare impacts of freezing in air at industry scales are largely unexplored and the humaneness of the practice is currently debated.
    • Mites. Mites are highly prevalent in most production facilities; their welfare impacts are unknown. Research on the welfare effects and possible prevention of the most common mites would be beneficial.
    • Genetic modification and artificial selection. The progressive physiological and behavioral effects of genetic modifications/artificial selection across the lifespan should be tested prior to the adoption of new lines by the industry.
    • Probiotics. Some probiotics may support immune health and nutrient utilization if the feed is innoculated prior to YML consumption; further, some fungal secondary metabolites may be beneficial. Probiotic research may start with P. pentosaceus, B. subtilis, B. toyonensis, and E. faecalis, which have already demonstrated potentially positive effects as food additives, while F. poae, F. proliferatum, and F. sporotrichioides may be worth investigating on the fungal side.
    • Giant YML. It is currently unknown whether the practice of rearing giant YML through supplemental JH in feed restricts behaviors or harms physical health. Researching the behaviors and physiology of giant and normal YML, particularly in relation to traits associated with increased fat body size in other insects (e.g., heart dysfunction, hyperglycemia, reduced activity levels, and insulin resistance), will be essential to determining whether this practice harms YM welfare.
    • Overheating. It may be possible to avoid localized larval overheating by using alternative crate materials and substrates, reducing YML densities, and employing monitoring devices—which would improve both welfare and productivity.
    • Light. Research is needed on the welfare effects of photoperiod, and the type of light provided, for rearing YM at all life stages. 
    • Handling. Handling-associated stress (due to light, fasting/washing, vibrations, etc.) should be assessed for potential negative welfare effects. Additionally, producers should test if particular practices can be less frequent, shortened, or discontinued without affecting product quality/safety (e.g., fasting).
    • Prevalence of welfare concerns. No data are available on the prevalence of most welfare concerns in industry conditions. Likewise, no data are available on the practices producers employ to maintain high welfare conditions for their animals. Research that documents prevalence and assesses how changes in rearing practices affect welfare will be essential for guiding high welfare standards and increasing economic productivity.
  • The scale of the Insects as Food and Feed industry is growing rapidly; previous estimates of industry scale (Rowe 2020) are now likely out of date. Continual, accurate updates of industry growth – with breakdowns by insect species and life stage, country, and facility type – would assist in generating the most important improvements for farmed insect welfare.

Biological and cognitive sciences

  • Studies on the sentience and capacity for nociception/pain in any of the farmed insects (see Table 13 from Gibbons et al. 2022, below) would be valuable; larval insects are of high priority, especially the black soldier fly and yellow mealworm as large numbers are slaughtered before adulthood. Students interested in completing sentience-related projects should begin by checking tables 11 & 12 in Gibbons et al. 2022 to determine where their efforts would be most valuable in filling research gaps.
    • These gaps include neurobiological studies, generally on: nociceptor presence and function; integrated nociception in higher order brain regions; the development of higher order brain regions across juvenile life stage; and modulation of responses to noxious stimuli with exogenous or endogenous chemicals (preferably, with mechanism described).  
    • These gaps include behavioural studies, generally on: motivational trade-offs; self-protective behaviours in response to noxious stimuli; associative learning (with particularly emphasis on trace conditioning); and analgesic self-administration. 
    • Some studies are already underway for crickets and black soldier flies; contact Meghan Barrett (director@insectwelfare.com) if you want to work on research directions listed here to avoid duplicating effort across labs already known to be working on this area.

  

  • Many insect orders are not represented in the Gibbons et al. 2022 review of insect pain. This is generally due to a lack of data. However, to best understand insect welfare, a more phylogenetically-informed approach to each criteria in Gibbons et al. 2022 should be taken. Therefore projects that collect new data for missing taxa for each neurobiological and behavioural criteria, back to the most ancestral Hexapods (Collembola), will be especially useful. This will allow future reviews on insect (Hexapod) pain to study the evolution and presence/absence of these traits across the entire class of ‘Insecta’ and lend greater confidence to any conclusions we might draw about insect pain. 
  • Further, although they are not technically insects, springtails (Collembola) and mites (Acari) are the most abundant arthropods in terrestrial ecosystems. There are no peer-reviewed studies or reviews of their possible sentience and or welfare issues at this time. Collecting new data on these groups in relation to the neurobiological/behavioural sentience criteria in Gibbons et al. 2022, or even reviewing the literature on the evidence available to date, would be informative for prioritizing wild arthropod welfare questions. 
  • Nothing is known about the scale of insect use in research, or the prevalence of different welfare-impacting research practices that would be tractable for improvements. This data would be useful for researchers interested in innovating/researching improvements to current practices.

Biological and ecological sciences

  • Studying the behaviors and survivorship of farmed insect species in the wild would fill a gap in the literature and provide indications of what behaviors and conditions are natural to them. This could give an indication of whether farmed conditions are comfortable for them, and in particular whether they are too densely crowded. It would also be valuable to estimate the length and variance in their life cycle outside of captivity, and determine juvenile survivorship to adulthood and causes of juvenile mortality.
  • Pesticides likely represent significant welfare concern for insects, as well as the most common terrestrial arthropods: Collembola and Acari, springtails and mites. Research prioritizing more humane insecticides that are better for the welfare of these groups could be very impactful.
  • Beyond general, broad acting pesticides, some specific insect species are also targeted with order- or species-specific pesticides. This can happen, for example, in the case of outbreaks when crops are generally consumed by a specific pest species or in invasive species management. Studying the most humane/effective ways of controlling these species may be more tractable than broad-action pesticide reform. Studies should consider the humaneness of the method of lethality (e.g., suffering x time to death), its effectiveness (e.g., what are its effects on population size long-term, such that overall fewer animals have to experience the method of lethality), its non target animals welfare (and environmental) impact, and the economic costs of different methods (affecting the likelihood that they could reasonably be employed).
  • Humans manage land in very different ways; almost no research has systematically assessed the scale of terrestrial arthropods on managed/unmanaged lands or the impacts of management practices on their welfare. Estimating 1) the scale of management practices/unmanaged land types; 2) the number of arthropods of different types in each scenario; and 3) the kinds of welfare challenges faced by those arthropods, would be very useful. Although conducting this research empirically at a global scale would be impossible, researchers could either do a very thorough review of a few land types in their local area or conduct a literature review to see what kinds of estimates can be produced from the currently available data.
  • Developing and testing the validity and costs of novel methodologies for reducing low-welfare research practices (e.g., developing eDNA to replace lethal sampling of insects in plant-pollinator studies).

Philosophy and ethics

  • Barrett & Fischer (2022) bring up a future area of philosophical research: “The availability of insect protein raises questions about how to make trade-offs involving different species, with different probabilities of sentience, and radically different numbers of farmed individuals…It is important, therefore, to develop decision-making frameworks for such trade-offs that allow stakeholders to consider the importance of several factors: the number and kinds of individuals affected, the size and severity of the welfare impacts, and indirect effects on, e.g., sustainability goals.”
    • Some example trade-offs:
      • Using insect protein to replace fishmeal, where the welfare impacts of the IAFF industry rearing a large number of insects must be compared to the effects of commercial fishing operations rearing a smaller number of fish.
      • Using insect protein to feed other livestock, where there have been welfare benefits reported for fish, chickens, and pigs consuming BSFL (against the negative welfare impacts of the industry on the BSFL).
      • Assessing the sustainability (or economic development) benefits of insect farming vs. its welfare costs, in addition to the potential welfare benefits of sustainable agriculture for human and wildlife welfare.

Further resources

Find supervision, mentorship and collaboration

The Insect Welfare Research Society has a public and private membership directory (members can choose how they wish to be listed) that is currently growing. Students should contact the IWRS leadership to see if there are any members relevant to their research interests.

The Animal Welfare Research Network has a membership directory and list of PhD and other opportunities. Animalwelfaregroup.slack.com is a Slack channel where early career researchers and students can find opportunities.

Find courses and funding

The IWRS runs student awards in the fall, awarding $2000 USD to answer questions on insect sentience and welfare. Other possible sources of grant funding for insect welfare projects (though some of these may not be targeted to the student level) are listed on their website.

Our PhD funding database can also help you find potential sources of funding if you’re a PhD student interested in this research direction. 

Newsletters

Sign up for the Insect Welfare Research Society listserv to hear about other opportunities in the field. 

Apply for the Effective Thesis newsletter to hear about opportunities such as funding, internships and research roles in this area. 

Contributors

This profile was published 10/05/23. Thanks to Meghan Barrett for writing this profile. Learn more about how we create our profiles.

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Research on wild animal welfare

Read our introduction on research to improve the wellbeing of wild animals.

Black soldier fly sentience and welfare

Trillions of black soldier fly larvae are projected to be raised for slaughter each year in the coming decades. Read this profile to learn more and find related research questions.