EFFECT OF GLYPHOSATE AND 2,4-D HERBICIDES ON AFRICANIZED Apis mellifera BEE COLONIES

• Grant number: 24/06729-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: August 31, 2025
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Production
• Principal Investigator: Ricardo de Oliveira Orsi
• Grantee: Larissa Beatriz Costa Oliveira
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The extensive use of pesticides has been identified as a crucial factor in bee mortality, which can become contaminated through ingestion as well as direct or indirect contact with the active ingredient. Generally, these forms of contamination result in significant effects on bees, potentially leading to immediate mortality or affecting their development, physiological functions, and behaviors. In this context, the present proposal goals to evaluate the effect of herbicides (Glyphosate and 2,4-D), commonly used, on Apis mellifera bees. For this purpose, 15 colonies of Africanized Apis mellifera bees housed in Langstroth model nuclei will be used, distributed across the following treatments: T1: control; T2: Glyphosate (273.93 µg/bee) and T3: 2,4-D (127.70 µg/bee). Each colony in the treatments will receive 1 L of sugar syrup (contaminated or uncontaminated) through a Boardman feeder for seven days, evaluating food consumption, mortality, and population development. For the calculation of the quantity of herbicides added to the sugar syrup, an approximate population of 20,000 bees will be considered, with a consumption of 50 µL per bee. Thus, the sugar syrup will be prepared with 5.48 grams of glyphosate per liter of syrup and 2.55 grams/L of 2,4-D, containing the active ingredient of each herbicide constant in the formulation of commercial products. After seven days, the queens of the colonies will be eliminated for the "natural pulling" of queen cells, and the number of queen cells will be recorded. After, half of the queen cells will be removed from the colonies, placed in cages, and kept in an incubator (32°C and 70% RH) until the emergence of the queens. The number of emerged queens per treatment will be recorded, and the following parameters will be evaluated: queen weight (mg) and length of fore and hind wings (mm), using an analytical balance and a magnifying glass, respectively. The remaining queen cells in the colonies will be evaluated to check for queen emergence, mating, and the onset of egg laying. After the onset of egg laying, population development and adult bee mortality will be assessed for a period of 60 days. Differences between treatments will be compared using ANOVA, followed by Tukey's test (p<0.05) for multiple comparisons.