Indirect Effects of Mosquito-Control Insecticides on Pollinator Visitation and Reproductive Success of Flowering Plants in the Florida Keys

Efforts to chemically manage mosquito populations often unintentionally impact beneficial insects, particularly pollinators. A decline in pollinator activity can lead to reduced pollination success, diminished fruit and seed production, and increased self-fertilization, which may compromise genetic diversity—especially in rare plant species. This study examined three yellow-flowered plant species, from distinct families and with different floral structures, across three islands in the Florida Keys. These islands contain conservation areas adjacent to residential zones where mosquito insecticides are routinely applied. Using field observations of pollinator visitation and fruit set in three plant species across control and insecticide-exposed sites, we evaluated whether mosquito-control spraying reduces plant reproductive success. Observations made before and after spraying revealed that flowers blooming post-treatment received fewer visits from pollinators. Notably, fruit production declined in species reliant on pollinators for reproduction. The findings suggest that insecticide use near protected habitats poses a significant risk to pollinator-dependent plants. For species unable to self-pollinate effectively, this could result in reduced reproductive output and threaten long-term survival.