Strengthening of negative density dependence mediates population decline at high temperatures.

While temperature is well known to affect many life history traits of ectothermic organisms, any attempt to scale up these individual-level processes to population-level consequences must assume a relationship between temperature and the strength of per capita density dependence. Yet, theory has made contrasting predictions about this relationship, and we still need clear experimental tests to determine which relationship is realized in natural systems, especially in heterotrophs. Here, we experimentally isolated and quantified the thermal response of density dependence from the population dynamics of the herbivore Daphnia pulex.

Predation and competition drive trait diversity across space and time.

Competition should play a key role in shaping community assembly and thereby local and regional biodiversity patterns. However, identifying its relative importance and effects in natural communities is challenging because theory suggests that competition can lead to different and even opposing patterns depending on the underlying mechanisms. Here, we have taken a different approach: rather than attempting to indirectly infer competition from diversity patterns, we compared trait diversity patterns in odonate (dragonfly and damselfly) communities across different spatial and temporal scales along a natural competition-predation gradient.

Survival-Larval Density Relationships in the Field and Their Implications for Control of Container-Dwelling Mosquitoes.

Population density can affect survival, growth, development time, and adult size and fecundity, which are collectively known as density-dependent effects. Container larvae often attain high densities in nature, and those densities may be reduced when larval control is applied. We tested the hypothesis that density-dependent effects on survival are common and strong in nature and could result in maximal adult production at intermediate densities for , , and .