Figures and data
Treatments of intraspecific richness, interspecific richness, and water addition used in each of the five study sites.
White tiles represent treatment combinations which were not tested in a given site.
Hierarchical Bayesian model parameter estimates for the effects of water availability intraspecific and interspecific Piper richness on herbivory, herbivorous insect richness, and Piper survivorship across sites Violins represent the cross-site posterior parameter distribution for each relationship in site level hierarchical Bayesian models.
Black lines represent the median posterior estimate and white bars represent 95% credibility intervals. Percentages above violins indicate the probability of an effect being positive or negative (as indicated by a negative probability) in response to an increase of the independent variable. Distributions for water addition compare watered and control plots; distributions for interspecific richness compare Piper species richness standardized as the proportion of the maximum richness used at a site; distributions for intraspecific richness compare low and high intraspecific richness treatments; distributions for insect richness compare responses per insect taxon present on an individual leaf
Direct and indirect effects of plant diversity and water availability on insect herbivores at five study sites.
Bayesian structural equation models comparing effects of different drivers of herbivorous insect richness and herbivory at five sites. Standardized path coefficients are means of the posterior distribution for the effects estimated at each causal path. Positive relationships are indicated in blue with triangular heads, and negative relationships are indicated in red with circular heads. Black arrows indicate path coefficients of zero magnitude. Dot plots summarize the standardized mean of the posterior distribution for each causal path with 95% and 80% credibility intervals. Asterisks indicate causal paths where the probability of an effect being positive or negative is >95%.
Interactions between intraspecific or interspecific richness and water availability on herbivory, herbivorous insect richness, and Piper survival Bars indicate mean response and standard error of the mean.
Percentages indicate the probability that the two slopes are different as calculated using site level hierarchical Bayesian models. Due to high mortality in Peru, interactions between water and intraspecific richness could not be compared for any responses except mortality. Single and two species richness plots have been combined for visualization purposes only.
Path models and explanatory hypotheses.
Black arrows indicate causal paths between exogenous and endogenous variables.
Study site characteristics and experimental details.
Species of Piper used at each study location
Mean parameter estimates and probability of direction (PD) for the effects of increases in intraspecific diversity, interspecific richness, water availability and insect richness on measures of herbivory, plant mortality, and insect richness.
Treatments and number of plots used across sites
A) Treatments of intraspecific richness, interspecific richness, and water addition at the beginning of the experimental period at each of the five study sites, and B) final treatments at the end of the experimental period in each site. White numerals indicate number of plots used. Changes in Piper species richness and the loss of some treatment combinations was due to Piper mortality over the course of the experimental period.
Precipitation levels at study sites where the water addition treatment was applied
A) Monthly precipitation over the experimental period at Costa Rica (CR), Ecuador (EC), and Peru (PE). B) difference in monthly precipitation from climate normals at the three sites across the experimental periods for those sites. Bars indicate median values, black points indicate mean values. C) Cumulative precipitation over the course of the experimental period. Dotted lines indicate average cumulative precipitation, shaded regions indicate 95%, 80% and 50% quantiles. Climate normals are based on monthly precipitation for a period from 1958 to 1998.
Overall herbivory, plant mortality, and insect richness at five study sites
A) Percent herbivory, percentage of leaves with any damage, herbivorous insect richness, and percent mortality of Piper in Costa Rica (CR), Ecuador (EC), Peru (PE), Uaimii (UI), and Mogi-Guaçu (MG), across treatments. B) Proportion of herbivorous insect taxa observed at each site measured by feeding damage patterns. Colored regions indicate the percentage of damage observations contributed by each taxon. C) Proportion of herbivory attributed to each taxon at five study sites. Colored regions represent the percentage of each leaf consumed by each taxon at each site. White tiles represent sites where no leaf damage by that insect taxon was observed.
HBM parameter estimates of percent herbivory, percentage of leaves with damage, variance in herbivory, and percent Piper survival against levels of A) water addition, B) Piper intraspecific richness, C) Piper interspecific richness, and D) insect richness at each site.
Violins represent the posterior parameter distribution for each relationship across sites and within sites in Costa Rica (CR), Ecuador (EC), Peru (PE), Uaimii (UI), and Mogi-Guaçu (MG). Black lines represent the median posterior estimate while white bars represent 95% credibility intervals. Percentages above violins indicate the probability of an effect being entirely positive or entirely negative in response to an increase of the manipulated variable. Distributions for water addition compare unwatered control and watered plots; distributions for interspecific richness compare Piper species richness and are standardized as a percentage of the high richness treatment level; distributions for intraspecific richness compare low and high intraspecific richness plots; distributions for insect richness compare responses per insect taxon present at the leaf level
HBM posterior parameter estimates of insect richness compared to levels of A) water addition, B) Piper intraspecific richness, and C) Piper interspecific richness
Violins represent the posterior parameter distribution for each relationship across sites and within sites at Costa Rica (CR), Ecuador (EC), Peru (PE), Uaimii (UI), and Mogi-Guaçu (MG). Black lines represent the median posterior estimate while white bars represent 95% credibility intervals. Percentages above violins indicate the probability of an effect being entirely positive or entirely negative in response to an increase of the manipulated variable. Distributions for water addition compare the unwatered control and watered plots; distributions for interspecific richness compare Piper species richness and are standardized as a percentage of the high richness treatment level; distributions for intraspecific richness compare low and high intraspecific richness plots
Bayesian structural equation models for drivers of insect richness, herbivory and Piper survival at three sites, including interactions between intraspecific and interspecific richness, and water addition.
Path coefficients indicate the standardized mean of the posterior distribution for each causal path. Positive relationships are indicated in blue with triangular heads, and negative relationships are indicated in red with circular heads. Dot plots indicate the standardized mean of the posterior distribution for each causal path in A with 95% and 80% credibility intervals. Asterisks indicate causal paths where the probability of an effect being entirely positive or entirely negative is > 95%.
