Measuring health and frailty in wild insects

Grantee: Jelle Boonekamp

Institutions: University of Glasgow, United Kingdom

Grant amount: $63,536

Grant type: Ad hoc

Focal species: Field cricket (Gryllinae)

Conservation status: Least concern

Disciplines: Physiology, entomology

Research location: United Kingdom

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Project summary

From an evolutionary perspective, health and well-being is best expressed in terms of fitness variation, the logic being that animals who are optimally adapted to their local environment should be healthy. Hence, health and fitness are intimately entwined on a conceptual level. Morphological, behavioral, and physiological traits that are predictive of fitness could provide potential biomarkers of health, and such approaches have been developed for many different wild vertebrate species. However, due to their small size and mobility, it has proven exceedingly challenging to follow individual insects longitudinally in the wild, let alone their descendants, to measure individual performance and fitness. Consequently, there is a paucity of literature on wild insect health and well-being.

The aim of this project is to address this knowledge gap by developing a non-invasive frailty index that measures the health of individual insects in their natural habitat and that can be applied across species. Analogizing to frailty indices used in human patients, this project will develop an insect frailty index using relevant traits applicable to many different insect species. In humans, the frailty index is highly predictive of morbidity and remaining life expectancy. Similarly, this project seeks to validate the insect frailty index against mortality and fitness data in an insect population by testing whether “frail” individuals have increased mortality risk and reduced fitness. 

This project is made possible by the work that we have done to establish a long-term field study of a natural population of crickets (WildCrickets.org). Using a network of 140 video cameras, all the adults in the population are longitudinally monitored from their emergence in early spring to their natural death in late summer. All their movements, reproductive behaviors, fights, and predation events are recorded, and fitness is measured by genotyping and counting the number of surviving genetic descendants in the next year.

Why we funded this project

Willingness to investigate the welfare of insects is somewhat rare, as are creative ways to assess their welfare. This project both proposed a potentially usable metric, and has access to an unusually useful resource through the WildCrickets.org project. While any particular approach to assessing welfare in insects is unlikely to work, we are hoping to seed enough approaches and strategies that others take up the call, eventually drawing in enough different approaches to produce usable strategies for assessing insect welfare in the wild. Finally, because many of the project resources were already acquired through other sources, we were to fund exclusively the welfare-focused aspects of the project.

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Improving the welfare of wild and captive animals with integrated in-situ and ex-situ behavioural monitoring

Grantee: Sarah Richdon

Institutions: Bristol Zoological Society, United Kingdom

Grant amount: $30,000

Grant type: Seed grants

Focal species: White clawed crayfish (Austropotamobius pallipes)

Conservation status: Endangered

Disciplines: Animal welfare science, marine biology

Research location: United Kingdom

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Project summary

This project will investigate the welfare impacts of translocating captive-bred white-clawed crayfish (Austropotamobius pallipes) into an existing wild population. Both resident and introduced individuals will be fitted with transponders and marked for behavioral monitoring. To evaluate welfare, the researchers will observe social interactions (e.g. aggressive interactions), behavioral diversity, and the animals’ use of their habitat. For example, emigration of native individuals from the focal habitat may be indicative of intraspecific competition intensified by the translocation. Body condition will also be scored as a metric of health and resource access.

Why we funded this project

We are excited to fund a project focused on the welfare of invertebrates, in this case an aquatic crustacean. The monitoring methods and some findings of this project may also be applicable to other aquatic taxa. Translocation is already a commonly used intervention in conservation, yet its welfare implications are poorly understood. By learning about these, translocation strategies could potentially be improved, and we might gain insights that could be applied to other welfare-motivated interventions.

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How do human activities impair the welfare of highly social fish?

Grantee: Joachim Frommen

Institutions: Manchester Metropolitan University, United Kingdom

Grant amount: $28,960

Grant type: Seed grants

Focal species: The princess of Zambia (Neolamprologus pulcher)

Conservation status: Least concern

Disciplines: Ichthyology, physiology, genetics/genomics

Research location: United Kingdom, Zambia

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Project summary

This project will investigate the welfare of a common fish species in Lake Tanganyika, the princess cichlid (Neolamprologus pulcher), as they are exposed to varying levels of human activity. Across eight populations representing a range of distances to human settlements and shipping routes, the researchers will monitor behaviors indicative of stress or aggression, and measure body condition and the brain tissue expression of five genes involved in stress physiology (glucocorticoid response pathway; crf, cyp11b, gr1, gr2, mr). These welfare indicators will be compared with specific environmental characteristics, including boat noise, water visibility (sedimentary and algal load), human fishing intensity, temperature stress, and structural complexity of the local environment.

Why we funded this project

By focusing on an established model system (cichlids), this project is able to benefit from background knowledge of the species’ ecology and behavior and proceed to more neglected welfare questions, as well as potentially engaging a ready audience of cichlid researchers. An especially interesting component of this project is its investigation of brain gene expression to potentially better understand how stress physiology relates to an animal’s subjective experience.

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Identifying species traits underlying conservation translocation failure, to understand risk factors, help redesign procedures, and pre-emptively protect vulnerable wild animals

Grantee: Emma Mellor

Institutions: University of Bristol, United Kingdom

Grant amount: $226,987

Grant type: Fellowship

Focal species: Multi-species

Research location: United Kingdom

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Project summary

This project focuses on using survival as an indicator of welfare in relation to life history characteristics using a database of animal translocations. Traits significantly relating to successful translocation (as indicated by post-release survival) would be identified as risk or protective factors for a variety of animals. The project aims to enable inferences about welfare risk factors for species beyond the datasets available by integrating a phylogenetic approach to understanding welfare. Therefore, the project could provide valuable insights into susceptibility or life history characteristics that provide greater resilience to welfare harms and thus help characterize and prioritize sources of welfare concern in the wild. The project could directly inform translocation practices while providing insights into potential welfare interventions supporting multiple animal groups based on their life history traits. 

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Predicting density dependence of welfare of wild animal populations based on resource access linked to habitat availability and usage

Grantee: Ross MacLeod

Institutions: Liverpool John Moores University, United Kingdom

Grant amount: $159,744

Grant type: Challenge grants

Focal species: House sparrow (Passer domesticus)

Conservation status: Least concern

Disciplines: Ecological modeling, population ecology, animal welfare science

Research location: United Kingdom

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Project summary

This project seeks to adapt a habitat and population model to incorporate welfare and apply it to the study of an abundant and widespread avian species, the house sparrow (Passer domesticus). The researchers propose to utilize a variety of welfare metrics to validate model assumptions, which will then allow them to test assumptions related to the welfare implications of density-dependent population dynamics.

Why we funded this project

We funded this project because it addresses our proposal request very closely and proposes to investigate a key wild animal welfare question using a modeling framework. They are also planning to address their question using an abundant avian species. The project has high potential to inform future work focused on modeling total welfare in a population (i.e., combining both individual welfare and population size), and to create a model that can be replicated in other systems.

Find Ross’ other project, studying wild birds, here.

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Empirical assessment of welfare in wild American mink and Eurasian otters: the effects of intra- and inter-specific population density

Grantees: Lauren A. Harrington, Maria Diez Leon

Institutions: Oxford University, United Kingdom

Grant amount: $162,257

Grant type: Challenge grants

Focal species: American mink (Neovison vison), Eurasian otter (Lutra lutra)

Conservation status: Near threatened

Disciplines: Animal welfare science, community ecology, wildlife management

Research location: United Kingdom

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Project summary

This project seeks to determine whether the welfare of American mink (Neovison vison) is negatively impacted in the presence of high densities of Eurasian otters (Lutra lutra), whether both species’ welfare is compromised at relatively higher densities of conspecifics, and whether there is a seasonality to welfare impacts. The project will also assess whether behavioral time budget shifts in mink are associated with higher chronic stress levels, as a proxy for negative impact on mink welfare. These questions will be addressed by measuring welfare through several different domains, including behavioral (exploratory behavior, vocalizations), physical (body condition, ectoparasite load), and physiological (telomere length, fecal glucocorticoid metabolites and hair cortisol) metrics. 

Why we funded this project

This project has the potential to contribute significant information to the understanding of intra-specific density-dependent welfare and to the understanding of network effects among predator-prey and competitor interactions of wild animals. Its unusually diverse set of welfare metrics will allow for cross-validation, strengthening both this project and other projects applying the same metrics. The investigators each have a strong background in animal welfare and have made efforts to better align their work with  Wild Animal Initiative’s priorities for wild animal welfare, which makes them good candidates to carry forward the validation of these welfare indicators (particularly telomere attrition, which is still relatively immature in its use as a welfare indicator).

Find Maria’s other project, studying European minks, here.

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Social connections and their welfare implications in the wild

Grantee: Alex Thornton

Institutions: University of Exeter, University of Bristol, United Kingdom

Grant amount: $157,962

Grant type: Challenge grants

Focal species: Jackdaws (Coloeus sp.)

Conservation status: Least concern

Disciplines: Animal behavior, ornithology, animal welfare science

Research location: United Kingdom

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Project summary

This project seeks to understand the relationship between welfare and social interactions in wild bird populations. Using historical data, the researchers will also seek insight into how welfare varies among individuals in relation to the social system, early-life experiences, and interactions among individuals. They will also investigate whether social systems might play a role in helping to mitigate some of the negative anthropogenic impacts on welfare.

Why we funded this project

The study findings will help in understanding how wild animals cope with increasing temperatures and the impact of thermal stress on their welfare and health. Notably, previous work has suggested that T3 measurements in ungulates are especially sensitive to thermal stress, and so comparing T3 with other indicators based on different physiological pathways, such as glucocorticoids, could help researchers to diagnose the relative significance of different environmental stressors an animal is facing. The project’s behavioral metrics are also crucial for realizing that potential. A secondary reason for our interest in this project is that it has near-term policy implications, potentially highlighting the value of preserving or promoting specific landscape features for the ecosystem service they offer, in the form of shade, to wild ungulates.

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Validation and efficacy of faecal glucocorticoid metabolites as indicators of animal welfare

Grantee: Miriam Zemanova

Institution: University of Fribourg, Animalfree Research, Switzerland, Oxford Centre for Animal Ethics, United Kingdom

Grant amount: $28,500

Grant type: Small grants

Disciplines: Physiology, animal welfare science

Research location: Switzerland, United Kingdom

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Project summary

One of the central components of the stress response is the production of glucocorticoids (GC). The measurement of glucocorticoid levels in blood serum is therefore often used in animal welfare studies. However, it is not always apparent how valuable these measurements are for understanding stress reactions and their relationship to animal welfare. Moreover, blood sampling causes discomfort and is impossible without restraint or immobilization, which can be harmful to the animal and distort the experimental results. Fecal glucocorticoid metabolites (FGM) may be a suitable non-invasive alternative to blood analysis. While there have been several reviews written on fecal glucocorticoids, no systematic review of their validity as an animal welfare indicator is currently available. Therefore, through a systematic review process, this project seeks to provide an evidence base for the efficacy of non-invasive measurement of stress levels in wild animals using fecal glucocorticoids. Evidence will be compiled from studies that have assessed the correlation between fecal glucocorticoids and at least one other credible animal welfare indicator or factor that may be assumed to lead to impaired welfare. The project also aims to compare the performances of blood and fecal samples to assess stress levels. 

Why we funded this project

This study will review the evidence base for the validity and efficacy of non-invasively obtained glucocorticoid measurements and identify both challenges and best practices for working with fecal samples across multiple animal taxa. This is important because WAI is supporting multiple projects utilizing FGM as a physiological welfare indicator. Invasive measurements of stress, such as blood-based GCs, are disadvantageous because, without proper strategy and training, the stress induced by the sampling procedure can influence the measurement. Therefore, non-invasive measurement techniques are not only better for the animals, but may make the science less expensive and more reliable. Another reason we are supporting this study is that it will help to address a general need for better validation of the link between glucocorticoids and animal welfare, which is related to but conceptually distinct from physiological stress.

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Thermal imaging as a non-invasive welfare assessment tool for tracking the impact of environmental stressors across wild animal populations

Grantee: Ross MacLeod

Institution: Liverpool John Moores University, United Kingdom

Grant amount: $29,810

Grant type: Small grants

Focal species: Wild birds

Conservation status: Least concern

Disciplines: Physiology, animal welfare science, population ecology, ornithology

Research location: United Kingdom

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Project summary

This project aims to test and validate a standardized multi-species approach to monitoring physiological stress in wild birds by using thermal imaging cameras to measure the animals’ body surface temperature, which could enable tracking of chronic stress in wild populations facing different levels of environmental stressors. Building on pilot work, the project will focus on wild bird populations to develop a standardized thermal imaging methodology capable of monitoring surface temperature of a wide range of free-living wild animals. The methodology will be validated using bird communities visiting 54 standardized feeding and drinking stations spread across three urban-rural gradients in the UK, to quantify how changes in surface temperature are linked to starvation risk, predation risk, and human disturbance.

Why we funded this project

This approach to measuring wild animals’ physiological stress levels through thermal imaging analysis has great potential for scalable monitoring of large numbers of individuals and is usable for cross-species comparisons. We appreciated that this team was interested in addressing non-anthropogenic causes of suffering in starvation and predation, and in extending their method to other species that tend to be neglected (e.g., wild rodents). This work also relates to the project by Paul Jerem that we previously funded, creating a longer-term relationship between Wild Animal Initiative and project participants.

Find Ross’ other project, studying house sparrows, here.

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Raman spectroscopy as a novel non-invasive technique to assess wildlife welfare

Grantee: Teresa Romero

Institution: University of Lincoln, University of Portsmouth, United Kingdom

Grant amount: $19,100

Grant type: Small grants

Focal species: Tufted capuchin monkey (Cebus apella)

Conservation status: Critically endangered

Disciplines: Physiology, animal welfare science

Research location: United Kingdom

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Project summary

Steroid hormones are routinely used as biomarkers of stress and can be measured in different biological matrices, such as serum, saliva, feces, and urine. However, commonly used collection methods in wildlife are challenging; the stress they induce in the animals may affect hormone levels and also presents ethical issues. More recently, analysis of hormones accumulated in the hair has emerged as a non-invasive tool for measuring chronic stress in wildlife, but current limitations of hair analyses include variation in cortisol concentrations depending on sample preparation and the amount of hair required for cortisol extraction. This project will test whether Raman spectroscopy, which is suitable for the field and does not require sample pre-treatment, is a better way to use hair samples to assess steroid hormones. The planned methodology will make use of samples of mammalian hair with a known cortisol content using a control technique — liquid chromatography mass spectrometry — for comparison. The samples will be subjected to analysis by Raman to validate the technique and establish a robust analytical methodology for the non-invasive analysis of welfare biomarkers in wildlife.

Why we funded this project

Although this project is focused on development of chemical methods, we expect that the method, if validated, could make glucocorticoid assessment in the hair of wild animals much easier, increasing the future quantity and quality of that type of data. Hair is an especially interesting medium for glucocorticoid analysis because it integrates glucocorticoid levels in the body over time, causing the measurements to be more stable over time and potentially more indicative of baseline welfare, since the values are less sensitive to an animal’s most recent activities.

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