Abstract

Male and female plants of dioecious species often experience differential herbivory, possibly due to differences in defences such as secondary metabolite composition or nutritional quality. These plant sex effects on herbivory have been extensively studied for plant individuals, but not for stands/populations. For mobile herbivores, such as deer, stands may be a more relevant scale to study than individual plants. We predicted that male Salts viminalis plants should be subject to more extensive roe deer (Capreolus capreolus) browsing than female plants due to weaker defence in male plants. Furthermore, we expected that mixed-sex stands should experience more damage than monosexual stands due to positive effects of diet mixing on browsing by generalists. We tested for differences in roe deer browsing in plots that were either monosexual male or female, or a mix of male and female plants in a replicated field experiment. Roe deer browsing was estimated after one growth season with heavy herbivory. We also measured plant secondary metabolite concentrations and nitrogen content in leaves from all experimental clones to test the assumption that the sexes differed in defence or nutrients. Mixed-sex plots were more extensively browsed than monosexual plots. However, there was no difference in browsing between male and female plant individuals within mixed-sex plots or between monosexual plots. Plant secondary metabolite profiles differed between male and female plants, while nitrogen content did not. Our findings suggest that the diversified plant secondary metabolite contents of mixed-sex plots may have led to more extensive herbivory. Higher browsing of plant sex mixes may impact both natural and commercial S. viminalis stands with different sex ratios.

Keywords

Dioecy; Detoxification limitation hypothesis; Plant secondary metabolites; Herbivory

Published in

Environmental and Experimental Botany
2018, Volume: 146, number: Special issue, pages: 62-67
Publisher: PERGAMON-ELSEVIER SCIENCE LTD

SLU Authors

• Moritz, Kim

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Björkman, Christer

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Stenberg, Johan A.

  • Department of Plant Protection Biology, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network


UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1016/j.envexpbot.2017.10.015

Permanent link to this page (URI)

https://res.slu.se/id/publ/93854