Glyphosate commercial formulation negatively affects the reproductive success of solitary wild bees in a Pampean agroecosystem

Abstract

Glyphosate is the most widely used herbicide worldwide and it could have negative effects on wild bees. We study the effect of glyphosate commercial formulation on the nesting behavior of wild solitary bees (Megachile spp.) and the survival of immature stages in a Pampean agroecosystem. In four plots without agricultural management located in an agricultural field, we placed 480 wooden trap-nests. The traps were sprayed with two different concentrations of glyphosate commercial formulation and only with water. The number of cells per nest was significantly lower in glyphosate treated traps compared with the water treatment. The probability of finding breeding cells was two times higher in nests without glyphosate commercial formulation compared with treated nests. Larvae completed their development and emerged as adults approximately four times more in nests without glyphosate commercial formulation, relative to those with glyphosate. Our results indicate that glyphosate commercial formulation could be conditioning the behavior of the nesting females and it is affecting their reproduction.