Abstract
We tested how the status of the parent taxa, host or non-host, influences the resistance of F1 hybrids to herbivores. To do this we used two different hybrid lines. Hand pollination was used to produce pure individuals and F1 hybrids between Salix caprea and S. repens, and S. caprea and S. aurita. Leaves from these individuals were presented to adults of two chrysomelid species, Lochmaea caprea and Crepidodera fulvicornis, in multiple-choice preference tests. Lochmaea caprea showed an additive response: its level of grazing of the F1 hybrids of S. caprea (host) and S. repens (non-host) was mid-way between that of the parent species. This was consistent with the inheritance pattern of condensed tannins in hybrids. This suggests an additive inheritance of resistant traits and a linear (dose dependent) response by the herbivore. When both parent taxa (S. caprea and S. aurita) were hosts, L. caprea utilization did not differ between any of the plant categories (F1 hybrids and parents). Crepidodera fulvicornis exhibited a dominant response towards the susceptible parent for the S. caprea ¥ S. repens crosses and a dominant response towards the resistant parent for S. caprea ¥ S. aurita crosses. This indicates that C. fulvicornis might respond to changes in resistant trait at specific thresholds. Our results suggest that different herbivores, even those with a similar host plants range, differ in their response to hybrids. One way to gain knowledge of the proximate and ultimate explanations for these differences could be to compare the response of different herbivores to different distinct hybrid lines.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have