Data from: Decreasing predator density and activity explain declining predation of insect prey along elevational gradients

Predation, which is a fundamental force in ecosystems, has been found to
decrease in intensity with elevation and latitude. The mechanisms behind
this pattern, however, remain unaddressed. Using visual sampling of
potential predators and live flies as baits, we assessed predation
patterns along 4000-meter elevation transects on either side of the
equatorial Andes. We found that at the lower elevations around eighty
percent of predation events on our insect baits were due to ants. The
decline in predation with elevation was mainly driven by a decline in the
abundance of ants, whose importance relative to other predators also
declined. We show that both predator density and activity (predation rate
per individual predator) decreased with elevation, thus ascribing specific
mechanisms to known predation patterns. We suggest that changes in these
two mechanisms may reflect changes in primary productivity and metabolic
rate with temperature, factors of potential relevance across latitudinal
and other macroecological gradients, in particular for ectotherm predators
and prey.