ABSTRACT
The diversity and abundance of wild insect pollinators have declined in many agricultural landscapes. Whether such declines reduce crop yields, or are mitigated by managed pollinators such as honey bees, is unclear. We found universally positive associations of fruit set with flower visitation by wild insects in 41 crop systems worldwide. In contrast, fruit set increased significantly with flower visitation by honey bees in only 14% of the systems surveyed. Overall, wild insects pollinated crops more effectively; an increase in wild insect visitation enhanced fruit set by twice as much as an equivalent increase in honey bee visitation. Visitation by wild insects and honey bees promoted fruit set independently, so pollination by managed honey bees supplemented, rather than substituted for, pollination by wild insects. Our results suggest that new practices for integrated management of both honey bees and diverse wild insect assemblages will enhance global crop yields.
Subject(s)
Crops, Agricultural/growth & development , Fruit/growth & development , Insecta/physiology , Pollination , Animals , Bees/physiology , Flowers/physiologyABSTRACT
Pacific lion-paw scallops were collected from natural aggregations in Laguna Ojo de Liebre (Pacific Ocean), the Gulf of California, and from aquaculture facilities for genetic diversity analyses. Mitochondrial DNA sequencing uncovered two highly supported clades separated by 2.5% divergence. Data from ten microsatellite markers suggest individuals from these mitogroups are introgressed, raising questions about the mitotype origin. Some evidence suggests gene flow between La Paz and Ojo de Liebre; otherwise the Gulf of California and Ojo de Liebre are acting as two distinct populations. It is unclear whether translocations between sites have influenced the observed genetic structure or whether gene flow has been facilitated by past geologic events. Finally, scallops spawned for aquaculture are unique from the wild and have significantly less diversity. These results warrant the attention of managers and producers who should work to monitor and conserve genetic diversity in both wild and aquaculture populations.