Effects of larval exposure to the fungicide pyraclostrobin on the post-embryonic development of Africanized Apis mellifera workers

The ingestion of the fungicide in the larval stage can impair the bee development and the health and performance of the colony. In this perspective, studies that consider the effects of fungicides in the different stages of bee development are crucial for a better interpretation of the risks of exposure.
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Effects of larval exposure to the fungicide pyraclostrobin on the post-embryonic development of Africanized Apis mellifera workers Environmental Advances 4 (2021) 100069 Contents lists available at ScienceDirect Environmental Advances journal homepage: www.elsevier.com/locate/envadvEffects of larval exposure to the fungicide pyraclostrobin on thepost-embryonic development of Africanized Apis mellifera workersCaio Eduardo da Costa Domingues a,∗, Rafaela Tadei b, Lais Vieira Bello Inoue a,Elaine Cristina Mathias da Silva-Zacarin b,∗, Osmar Malaspina aa Universidade Estadual Paulista (UNESP) - “Júlio de Mesquita Filho”, Instituto de Biociências (IB), Departamento de Biologia, Centro de Estudos de Insetos Sociais(CEIS), Rio Claro, SP, Brazilb Universidade Federal de São Carlos (UFSCar), Departamento de Biologia (DBio), Laboratório de Ecotoxicologia e Análise de Integridade Ambiental (LEIA), Sorocaba,SP, Brazila r t i c l e i n f o a b s t r a c tKeywords: Among the more than twenty thousand bee species currently described, Apis mellifera stands out for its highAfricanized bee economic relevance due to crop pollination. In recent decades, many studies have registered a decline in beeLate effects populations associating multiple factors, including pesticides. These molecules can arrive through residues presentIntestine in the nectar and pollen, which can be ingested by the larvae. However, studies that contemplate the effects ofPeritrophic matrix fungicides on larvae and adults are rare. Thus, the objective of the study was to evaluate the effects of the exposureCell death to pyraclostrobin in the larval phase and verify the late effects in newly emerged bees. The larvae were subjected to repeated exposure (third to the sixth day of the bioassay). The concentrations of pyraclostrobin consumption were 127.58 ng/larva (PT1), 13.16 ng/larva (PT2), and 4.24 ng/larva (PT3), both based on residues found in the field like as pollen and bee bread. The effects on larval mortality, pupation, emergence and survival rates, and median lethal time of newly emerged worker bees were evaluated. We also evaluated cell death and chitin marking of the peritrophic matrix in the intestine of larvae and newly emerged bees. No adverse effects were observed on the post-embryonic development of the larvae and survival time of the newly emerged workers, showing tolerance to the fungicide. However, the intestine epithelium of larvae (PT1 and PT2) and adults (PT1) showed immunostaining for cell death and increased intensity of chitin marking in the peritrophic matrix, indicating a late effect of the pyraclostrobin fungicide. Thus, the ingestion of the fungicide in the larval stage can impair the bee development and the health and performance of the colony. In this perspective, studies that consider the effects of fungicides in the different stages of bee development are crucial for a better interpretation of the risks of exposure.1. Introduction dominant throughout Brazil and spread the Latin America and the south- western United States of America (Schneider et al., 2004). Although they The economic, agricultural, and ecological importance of Apis are known for their high defense capacity, they are currently entirelymellifera (Linnaeus, 1758) is reported in many studies (Morse and managed and due to their characteristics of a long time in ...