Components of local adaptation and divergence in pollination efficacy in a coevolving species interaction

Selection leading to adaptation to interactions may generate rapid evolutionary feedbacks and drive diversification of species interactions. The challenge is to understand how the many traits of interacting species combine to shape local adaptation in ways directly or indirectly resulting in diversification. We used the well-studied interactions between Lithophragma plants (Saxifragaceae) and Greya moths (Prodoxidae) to evaluate how plants and moths together contribute to local divergence in pollination efficacy. Specifically, we studied L. bolanderi and its two specialized Greya moth pollinators in two contrasting environments in the Sierra Nevada, California. Both moths pollinate L. bolanderi during nectaring, and one of them – G. politella – also while ovipositing through the floral corolla into the ovary. Firstly, field surveys of floral visitors and the presence of G. politella eggs and larvae in developing capsules showed that one population is visited only by G. politella and few..., In two natural populations of the plant Lithophragma bolanderi in the Sierra Nevada, California, USA, developing capsules of L. bolanderi were collected and stored in 68% ethanol. These capsules were dissected and, using a dissection microscope, the number of developing seeds, the number of undeveloping seeds, the number of Greya politella eggs, the number of G. politella larvae, and the number of partly eaten seeds were counted.
In addition, the corolla-opening diameter of L. bolanderi flowers in these two natural populations was measured using digital calipers.
In the laboratory, pollination efficacy experiments were conducted with field-collected Greya moths nectaring (G. obscura and G. politella) or ovipositing (G. politella) on greenhouse-grown L. bolanderi plants from their local and the non-local population. The capsules of the flowers involved in these experiments were dissected and counted as described above.
In addition, in the laboratory, time-lapse photography was used to ob..., ,