No.2 Seminar ： “Arms races” of insects and plants: Exploring the process of co-evolution as revealed by fieldwork studies
- Hirokazu Toju（The Hakubi Center）
- 2010/04/27 4:00pm
- The Hakubi Center (iCeMS West Wing 2F, Seminar Room)
- Japanese
Summary
In nature, organisms are embedded in biological communities in which they interact antagonistically and cooperatively with each other for their survival and reproduction. Since such interactions between species exert natural selection pressure on interacting species, armaments or cooperative traits of each species can change through the reciprocal adaptation process called “co-evolution.”
I have investigated the escalatory processes of coevolution (i.e., “arms races”), focusing on a plant-feeding insect species called the camellia weevil (Curculio camelliae) and its host plant, the Japanese camellia (Camellia japonica). Females of the weevil are characterized by their very long snouts, by which they bore the fruits of the Japanese camellia to make holes that are used for laying eggs into the seeds. However, since camellia seeds are surrounded by thick fruit coats, weevil females often fail to lay their eggs. A laboratory experiment showed that the longer the snouts of the weevil, the more likely the boreholes will reach seeds, whereas the thicker the camellia fruit coats, the more likely the plant will successfully protect its seeds. Thus, the snout length and fruit coat thickness can be involved in escalatory co-evolutionary races through the ecological interaction between the insect and plant species.
By reviewing my fieldwork studies on the insect–plant system, in this seminar I would like to discuss what mechanisms promote co-evolutionary “arms races” in nature.