Pollen Toxicity from Seed-Treated Cotton on Bees and Pollen Collection Capacity

Abstract

Apis mellifera bees that forage in agricultural fields may be exposed to pesticides through many routes. One of them is the collection of pollen contaminated with insecticides. In this study, we evaluate the mortality of adult honeybees exposed to pollen from cotton plants whose seeds were treated with insecticides thiamethoxam, clothianidin, imidacloprid and fipronil, and the pollen collection capacity of adult honeybees in cotton fields. Bee mortality based on linear regression analysis showed significant differences, but no differences were noted among treatments. According to the contrast analysis of the mean groups of insecticides against the mean of the control group, no significant differences were found, indicating a natural mortality for all treatments including the control. Quantitative analysis of the pollen revealed the presence of only cotton pollen grains on bees, indicating floral fidelity of Africanized honeybees. Pearson's correlation coefficient was positive, but statistically insignificant, for increase in pollen collection with time.

Dissipation kinetics of imidacloprid in cotton flower, nectariferous tissue, pollen and Apis mellifera products using QuEChERS method

“…Imidacloprid residue in corn plants was 6.6 ppb in the flowers and 2.1 ppb in pollen, when corn seeds were treated @ 0.7 mg kg −1 of seed 19 . However, De Souza et al 20 . found that A. mellifera mortality was not affected by the pollen from cotton plant grown from seed treated with thiamethoxam, clothianidin, imidacloprid and fipronil.…”

“…Imidacloprid residue in corn plants was 6.6 ppb in the flowers and 2.1 ppb in pollen, when corn seeds were treated @ 0.7 mg kg −1 of seed. 19 However, De Souza et al 20 found that A. mellifera mortality was not affected by the pollen from cotton plant grown from seed treated with thiamethoxam, clothianidin, imidacloprid and fipronil. Goulson, 21 reported that a dose of 1 g pollen and 2.6 mL nectar is required to be consumed by honey bees to obtain an oral median lethal concentration (LC 50 ) value of 5 ng bee −1 for imidacloprid, 7 which could get accumulated inside the body over a number of days or weeks.…”

Exposure of Apis mellifera (Hymenoptera: Apidae) to pollen grains of soybean plants (Glycine max L.) originated from treated seeds

“…These systemic products circulate throughout parts of the plants and are applied to seeds before sowing or are absorbed by plants from residues in the soil (BONMATIN et al, 2015). Although they are necessary to prevent pest damage, pollinators can also be exposed to their residues while foraging in treated crops (SIMON-DELSO et al, 2015), such as soybeans.…”