Data from: Direct and indirect effects of urbanization, pesticides, and wild insect pollinators on mango yield

Expanding cities increasingly encroach fertile farmlands, questioning the
viability of maintaining agriculture within and around them. Yet, our
knowledge on how urbanization influences pollinator communities and the
provision of pollination services to crops is limited, especially for the
urbanization hotspots of the Global South. Mango (Mangifera indica) is one
of the most important fruit crops in tropical countries. To analyze the
dependency of mango on its main insect pollinators, and the direct and
indirect effects of urbanization and insecticides on pollinator abundance
and mango yield, we conducted a pollinator exclusion experiment and
sampled flower visitors on 16 mango farms spread across rural-urban
landscapes in Bengaluru, a South Indian megacity. We found that allowing
flowers access to ants and flying visitors (bees, hoverflies, non-syrphid
flies), dramatically increased mango yield by 350%, highlighting the
importance of wild insects for mango pollination. We detected a trend
between wild bee abundance and the final fruit set, with an increase of
20% when the number of bees increased from 25 to 125. Urbanization did not
directly affect pollinator abundance or mango yield. However, the amount
of insecticide applications had strong negative effects on wild bee
abundance at low and intermediate levels of urbanization, while it had no
effect in highly urbanized areas, presumably because of higher
availability of flowering resources. Moreover, the amount of insecticides
decreased the weight of harvested mango fruits by almost 30%. This may
indicate trade-offs between conventional pest control and enhanced crop
yields through pollination by wild insects in rural areas. Synthesis and
applications. Our results indicate that mango production can be maintained
at a profitable level in urbanized landscapes with insect pollinators more
than tripling final yield. However, increasing use of insecticides,
besides raising farmers’ expenses, can have negative effects on wild
insect pollinators and mango yield, especially in rural areas. To
safeguard crucial pollination services, it is therefore critical to
conserve and promote wild insect pollinators by minimizing the negative
effects of insecticide applications in these areas.