Seminar: “Engineering a novel lifestyle: Melissotarsus and Rhopalomastix ants chew tunnels in healthy wood to accommodate their scale insect partners” by Dr. Christian Peeters

Dr. Christian Peeters, Institute of Ecology and Environmental Sciences, Sorbonne Université, Paris, France

Title:
Engineering a novel lifestyle: Melissotarsus and Rhopalomastix ants chew tunnels in healthy wood to accommodate their scale insect partners

Abstract:
Ants cannot eat leaves but they can feed on plants via sap-sucking insects.  Thousands of arboreal ant species interact with scale insects, giving protection against predators and weather in return for obtaining honeydew.  Family Diaspididae is the largest and most advanced among scale insects, yet they engage in mutualisms with only two genera of ants, partly because they do not excrete honeydew.  Melissotarsus and Rhopalomastix are sister genera with minute workers exhibiting a combination of unique morphological adaptations, including powerful mandibles and silk glands. This lineage engineered a novel ecological niche : they live permanently inside living trees, where adults and larvae feed on the flesh and shield secretions of diaspidids.  In Melissotarsus, mid- and hindlegs are modified as anchors for tunnelling, hence workers cannot walk on flat surfaces. Such extreme specialization of ant workers is possible because the queen caste can disperse by flight and walk outside host trees during colony foundation.