Drosophila as a pain model and the possibility of pain in insects

Drosophila melanogaster has proven to be a valuable model for studying pain in humans. What, if anything, does D. melanogaster’s utility as a model system tell us about the organism itself? In particular, does its utility provide any evidence that Drosophila themselves feel pain? This presentation explores some key philosophical issues that bear on these questions.

First, researchers sometimes state that Drosophila are not being used to model the affective dimension of pain in humans, but rather some fact about nociception. This requires us to be more precise about the relevance of a model of human nociception to the felt experience of pain in humans. To answer this question, it is useful to compare and contrast the case of Drosophila with another biological model of human nociception—namely, the house mouse, Mus musculus.

Second, there are many kinds of models in science, not all of which support backward inferences about the model system. For instance, the US Army Corps of Engineers built a scale model of the San Francisco Bay to decide whether to build two large dams to improve access to drinking water. Despite this model’s utility, it would be inappropriate to infer that the model has many of the features possessed by the San Francisco Bay. Depending on the kind of model that Drosophila is supposed to be, what inferences are appropriate from the target system to the model system? By mapping out these issues, we can better appreciate the implications of studies that employ these organisms.