Effects of Herbicides on the Survival of the Brazilian Native Bee Melipona scutellaris Latreille, 1811 (Hymenoptera: Apidae)

Abstract

Native bees are key pollinators to native and cultivated plants. Understanding the effects of the products used in crops on bees is crucial and can help establish management measures that offer more protection. The aim of this study was to evaluate the influence of the 1/2 the commercial dose; the commercial dose (2,4-D 1,000 g a.i. ha-1, glyphosate 760 g a.i. ha-1, glyphosate + 2,4-D 760 g a.i. ha-1 + 1,000 g a.i. ha-1, and picloram 2% (v/v) and 2x the commercial dose of glyphosate, 2,4-D, picloram, and glyphosate+2,4-D on the survival of bees Melipona scutellaris by contact and oral exposure. We also evaluated the impact of herbicides used in semi-field realistic conditions on temperature control and weight of colonies of M. scutellaris. The results show that there was no decrease in longevity when half of the recommended field dose was applied. When field dose was used, topically exposed bees to glyphosate + 2,4-D had a decrease in longevity. In oral exposure both to the recommended field dose and the double dose, bees had reduced longevity, except those exposed to a double dose of 2,4-D. In semi-field conditions, there were no differences between control and exposure colonies. The data presented indicate that the herbicides may affect bees directly compromise their survival and indirectly they might affect the process of pollination.

Effects of Fungicide and Herbicide Chemical Exposure on Apis and Non-Apis Bees in Agricultural Landscape

“…Oral exposure of both 100% and twice the recommended field dose reduced the longevity for all compounds except for 2,4-D at twice the recommended field dose. Interestingly though, when separately evaluating the impact of these herbicides on M. scutellaris temperature control and colony weight in semi-field conditions, Nocelli et al (2019) found no differences between control and exposure treatments.…”

“…Increased superoxide dismutase isoenzyme activity was observed in both species after exposure to paraquat and is believed to be physiologically related to paraquat detoxification. A separate study observing the effect of oral and contact exposure to glyphosate, 2,4-D, picloram, and glyphosate + 2,4-D on the survival of Melipona scutellaris showed no decrease in longevity, following the application of 50% of the recommended field dose for all compounds (Nocelli et al, 2019). However, decreased M. scutellaris longevity was observed following a contact topical application of 100% of the recommended field dose for glyphosate + 2,4-D.…”

Review on the sublethal effects of pure and formulated glyphosate on bees: Emphasis on social bees

“…The toxicity of GLY in bees is still a little-studied topic, given the importance of these animals. As previously mentioned, lethal effects of exposure of several bee species to GLY formulations have been reported in recent years (Abraham et al, 2018;Battisti et al, 2021;Dai et al, 2018;Graffigna et al, 2020;Nocelli et al, 2019;Seide et al, 2018). In addition, research has shown that even when not causing the death of bees, GLY-based products can impact the health of these insects, generating sublethal effects, such as molecular and cellular alterations (Vázquez, Latorre-Estivalis, et al, 2020;Zhu et al, 2017b), and changes in the intestinal microbiota (Blot et al, 2019;, in behaviour/learning (Abraham et al, 2018;Luo et al, 2021) and in development and physiology (Odemer et al, 2020;Seide et al, 2018).…”

“…Although most of the studies published to date have focussed on the toxicity of insecticides in bee populations (Blacquière & van der Steen, 2017; Herbert et al, 2014; Lima et al, 2016), investigations into the effects of herbicides such as GLY and atrazine have also shown that these pesticides can affect the survival or have other undesirable health effects on these insects (Battisti et al, 2021; Belsky & Joshi, 2020; Nocelli et al, 2019). It is also worrying that sugar water solutions containing glyphosate at a certain concentration (10 ppb) were more attractive to bees than solutions without this herbicide when considering the possibility of nectar contamination in nature (Liao et al, 2017).…”