Changes in herbivory patterns and insect herbivore assemblages associated to canopy of Quercus laurina : importance of oak species diversity and foliar chemical defense

Key message Oak community diversity increase diversity of canopy insect herbivores and herbivory rates in Q. laurina through changes in foliar chemical defense. Abstract Tree diversity is a key factor that explains the variation in the composition of insect herbivores in the canopy, but for temperate ecosystems has been little study. Mexico has some geographical zones that are rich in oak species, coexisting between two and up to six species locally. Considering the associational effects such as vegetation complexity and the characteristics of neighboring plants, we evaluated whether communities of more diverse oak species harbor greater diversity of canopy insect herbivores, increasing the herbivory rates through changes in foliar chemical defense in Quercus laurina . Five study sites were selected representing a gradient of oak diversity. Five mature Q. laurina trees were selected per site to collect canopy phytophagous insects using fogging techniques and foliar chemical defense and herbivory were measured collecting leaves from the canopy. We found 3693 insects associated to Q. laurina trees along the oak diversity gradient were collected, where Tequila Volcano had the greatest diversity of herbivorous insects and oak species. Also, the highest rates of herbivory were in the sites with more oak diversity, as well positive relationships between chemical defense and herbivore community. Our findings indicate that at a local scale, oak diversity is the main factor determining insect herbivore diversity; the levels of herbivory and foliar chemical composition of Q. laurina . We highlight the importance of conservation zones with a high diversity of oaks, being key elements of the temperate forest that harbor high diversity of herbivore insects driving the plant–insect interactions.