July 17, 2024

 Hello all, a paper written by Marie Clifford is out in the Journal of Comparative Physiology A. Here’s Marie:
      I recently published a review paper with my advisor Jeff Riffell about how insects process smells, or chemical signals, that they encounter in the environment. When I told this to one of my friends, they asked, rather pointedly actually, “Why should we care what insects think?!”

      Well, chemical signals mediate a heap of insect behaviors that are directly relevant to agriculture, medicine, and more. Smells help bees choose which flowers to visit, guide crop pests to their mates, and enable mosquitoes to find the source of their next blood meal, among many other things. Understanding how insects process olfactory information can help us understand how to encourage insects in beneficial behaviors (like pollinating our crops), as well as how to thwart them in their less appreciated efforts (like spreading malaria or making enough hungry baby insects that we lose the food in our fields).  Changes in how insects perceive chemical signals can also lead to things like host shifts, which can lead to speciation.  This is interesting from an evolutionary perspective, but also from an agricultural perspective (apple maggot arose in the last 200 years or so from a species that laid its eggs on hawthorn fruits) and a medical one (mosquitoes that feed on humans have close relatives that feed on other animals instead). Insects, particularly the fruit fly Drosophila melanogaster, also serve as a model for understanding how the brains of other creatures (like us) encode olfactory information, remember this information, make positive or negative associations with it,  and translate it into behavior. 

      Our review focused on how insect brains process the information from chemical mixtures, which is much less well-studied than how insects process information from individual chemicals. This is totally neat because most of the smells that insects (and we!) encounter in the environment are complex mixtures of chemicals. Noticing small changes in those chemical mixtures can be critical to finding the right mate (your own species hopefully!) or, maybe more relatably, telling the difference between food that is still good to eat and food is growing some nasty microorganisms. Detecting small changes in a chemical mixture and that ought to motivate a change in behavior is actually incredibly difficult computationally, so it’s super cool to explore how brains deal with this problem!

Here’s the paper!

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