Plant genetic diversity yields increased plant productivity and herbivore performance

Abstract

Summary1. Plant genotypic diversity has important consequences for a variety of ecosystem processes, yet empirical evidence for its effects on productivity, one of the most fundamental of these processes, is lacking. In addition, the performance of insect herbivores in response to high genotypic diversity is unknown, despite previous work demonstrating differential herbivore performance among plant genotypes. 2. We manipulated genotypic diversity of the annual plant Arabidopsis thaliana in both the presence and absence of the generalist herbivore Trichoplusia ni under semi-natural growth conditions. We used nine genotypes (eight ecotypes and one mutant) of A. thaliana known to differ widely in functional traits. Productivity and insect biomass were measured in monocultures and mixtures of all nine genotypes grown at multiple fertilization levels and planting densities. 3. In both the absence and presence of herbivores, genotypic diversity increased plant productivity and survival. This effect was, for the most part, independent of fertility or density. Sampling or selection effects did not appear to be wholly responsible for these results as all genotypes were maintained in equal proportion and no single genotype became dominant for the duration of the experiment. 4. High diversity increased T. ni biomass and survival in all treatments. Insect biomass was positively, but not tightly, correlated to plant biomass, indicating that the higher herbivore performance observed in genotypic mixtures was only partially due to higher productivity. 5. Synthesis. Our data support the idea that even within a single plant species, genotypic diversity can exert strong influences on both the producer and herbivore communities. The exact mechanisms responsible for these effects and the relative importance of genotypic diversity in natural communities warrant further investigation.

Independent role of belowground organisms and plant cultivar diversity in legume-grass communities

“…Inconsistent with recent studies about the positive relationship of plant productivity and plant cultivar diversity (Hughes et al, 2008;Kotowska et al, 2010), no significant effect of plant cultivar diversity on plant biomass was detected in our study. van Ruijven and Berendse (2005) found that positive species richnessproductivity relationships strengthened over time in perennial plant communities through increased nutrient use efficiency, both spatially and temporally.…”

“…However, resistance effects can depend on the chosen cultivars, as Wolfe (1985) illustrated. Kotowska et al (2010) also found that leaf herbivory was more severe in populations with high plant cultivar diversity and argued that this was due to their high productivity. In our study, we did not find a difference in plant productivity between communities of different cultivar diversity, making this mechanism unlikely here.…”

“…Plant diversity itself has been found to lead to increased plant productivity and to alter herbivore performance (Hughes et al, 2008;Scherber et al, 2010). However, most studies have focused on species diversity (van der Heijden et al, 1998;Scherber et al, 2010;Eisenhauer et al, 2012), while the role of intraspecific diversity for ecosystem functions has only recently drawn interest (Kotowska et al, 2010;Ostfeld and Keesing, 2012). Moreover, little is known about the interactive effects that intraspecific plant diversity and soil biota may have on plant and aboveground herbivore communities, and ecosystem functions.…”

“…Yet intraspecific plant diversity has only recently received increasing attention. For example, the diversity of different cultivars of single plant species, such as Oryzae sativa L. (Zhu et al, 2000), Gossypium hirsutum L. (Yang et al, 2012) and Arabidopsis thaliana L. (Kotowska et al, 2010), was reported to have direct and indirect impacts on the enhancement of plant productivity, the resistance to herbivory and plant pathogens, as well as on predators of herbivores. Compared to single cultivars, high cultivar diversity of host plants was found to lead to increased resistance against plant pathogens and insect pests (Ostfeld and Keesing, 2012;Tooker and Frank, 2012).…”

Evidence for competition and cooperation among climbing plants

“…This idea plays a key role in hypotheses for the evolution of sex [3,4] and outcrossing [5] and has received some support in plant ecology (e.g. [6][7][8] and references therein).…”