Geoscience Reference
In-Depth Information
ABSTRACT
The past decade has seen the rise of high resolution datasets. One of the main
surprises of analysing such data has been the discovery of a large genetic,
phenotypic and behavioural variation and heterogeneous metabolic rates
among individuals within natural populations. A parallel discovery from
theory and experiments has shown a strong temporal convergence between
evolutionary and ecological dynamics, but a general framework to analyse
from individual-level processes the convergence between ecological and
evolutionary dynamics and its implications for patterns of biodiversity in
food webs has been particularly lacking. Here, as a first approximation to
take into account intraspecific variability and the convergence between the
ecological and evolutionary dynamics in large food webs, we develop a model
from population genomics and microevolutionary processes that uses sexual
reproduction, genetic-distance-based speciation and trophic interactions. We
confront the model with the prey consumption per individual predator,
species-level connectance and prey-predator diversity in several environmen-
tal situations using a large food web with approximately 25,000 sampled prey
and predator individuals. We show higher than expected diversity of
abundant species in heterogeneous environmental conditions and strong
deviations from the observed distribution of individual prey consumption
(i.e. individual connectivity per predator) in all the environmental condi-
tions. The observed large variance in individual prey consumption regardless
of the environmental variability collapsed species-level connectance after
small increases in sampling effort. These results suggest (1) intraspecific
variance in prey-predator interactions has a strong effect on the macroscopic
properties of food webs and (2) intraspecific variance is a potential driver
regulating the speed of the convergence between ecological and evolutionary
dynamics in species-rich food webs. These results also suggest that genetic-
ecological drift driven by sexual reproduction, equal feeding rate among
predator individuals, mutations and genetic-distance-based speciation can
be used as a neutral food web dynamics test to detect the ecological and
microevolutionary processes underlying the observed patterns of individual
and species-based food webs at local and macroecological scales.
I. INTRODUCTION
Food web data are typically based on limited sampling of individuals, often
with considerable and uneven aggregation of observations (
Cohen, 1978;
Polis, 1991; Woodward and Warren, 2007; Woodward et al., 2010
). Recently,
improved datasets using increased sampling effort and combining individual
diet observations with body size, abundance andmolecular data are becoming
