Urban buzz: role of wild pollinators in pollen load on 'Solanum lycopersicum' in Rosario

Abstract

The wild pollinator fauna in peri-urban vegetable gardens of Rosario (Santa Fe, Argentina) remains largely unknown, despite the fact that numerous crops, such as Solanum lycopersicum var. platense (tomato), benefit from the activity of these insects. Although tomatoes can produce fruits through self-pollination, insect-mediated pollination significantly enhances fruit production. This study had two main objectives: (i) to compile an inventory of wild pollinators in peri-urban tomato gardens, and (ii) to quantify pollen deposition on stigmas caused by insect visits. Observations were conducted on 600 tomato inflorescences in four gardens, recording the abundance, frequency, and behavior of floral visitors. The amount of pollen deposition on stigmas of flowers exposed to visitors was compared with that on stigmas of flowers excluded from visitors (n = 96). Nine morphospecies were identified, five of which corresponded to bees capable of performing buzz pollination, with the family Halictidae standing out for its abundance (107 visits). Bees that collect pollen through buzzing accounted for the majority of visits. The exposed stigmas showed more than twice as many pollen grains as the stigmas of excluded flowers. Peri-urban gardens may function as foraging sites for native pollinators, contributing to an increase in pollination.