Research Article

Evolutionary Biology

, Volume 36, Issue 3, pp 267-281

First online:

The Ancient Chemistry of Avoiding Risks of Predation and Disease

  • M. YaoAffiliated withDepartment of Biology, McMaster University
  • , J. RosenfeldAffiliated withDepartment of Pathology and Molecular Medicine, McMaster University
  • , S. AttridgeAffiliated withDepartment of Biology, McMaster University
  • , S. SidhuAffiliated withDepartment of Biology, McMaster University
  • , V. AksenovAffiliated withDepartment of Biology, McMaster University
  • , C. D. RolloAffiliated withDepartment of Biology, McMaster University Email author 

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Illness, death, and costs of immunity and injury strongly select for avoidance of predators or contagion. Ants, cockroaches, and collembola recognize their dead using unsaturated fatty acids (e.g., oleic or linoleic acid) as “necromone” cues. Ants, bees, and termites remove dead from their nests (necrophoric behavior) whereas semi-social species seal off corpses or simply avoid their dead or injured (necrophobic behavior). Alarm and avoidance responses to exudates from injured conspecifics are widespread. This involves diverse pheromones, complex chemistry and learning. We hypothesized that necromones are a phylogenetically ancient class of related signals and predicted that terrestrial Isopoda (that strongly aggregate and lack known dispersants) would avoid body fluids and corpses using fatty acid “necromones.” Isopods were repelled by crushed conspecifics (blood), intact corpses, and alcohol extracts of bodies. As predicted, the repellent fraction contained oleic and linoleic acids and authentic standards repelled several isopod species. We further predicted a priori that social caterpillars (lacking known dispersants) would be repelled by their own body fluids and unsaturated fatty acids. Both tent caterpillars and fall webworms avoided branches treated with conspecific body fluid. Oleic and linoleic acids were also strongly avoided by both species. Necromone signaling appears widespread and likely traces to aquatic ancestors pre-dating the divergence of the Crustacea and Hexapoda at least 420 million years ago.


Isopoda Caterpillars Death recognition Shelter selection Necromones Behavior Predation Disease Fatty acids