Evaluating the Impact of Commonly Used Pesticides on Honeybees (Apis mellifera) in North Gonder of Amhara Region, Ethiopia

Abstract

Global honeybee losses and colony decline are becoming continuous threat to the apicultural industry, as well as, for food security and environmental stability. Although the putative causes are still unclear, extensive exposure of bees to pesticides could be the possible factor for worldwide colony losses. This study was aimed at evaluating the impact of nine commonly used pesticide incidents on adult worker honeybees (A. mellifera) under the laboratory condition, in North Gonder of Amhara region, Ethiopia. Feeding test, contact test, and fumigation tests were carried out for each pesticide following the standard procedures, and each pesticide toxicity was compared to the standard toxic chemical, dimethoate 40% EC (positive control), and to 50% honey solution (negative control). The results revealed that all the tested pesticides caused significant deaths of the experimental bees ( P < 0.05 ) in all the tests when compared to the negative control. Diazinon 60% EC, endosulfan 35% EC, and malathion 50% EC were appeared highly toxic causing 100% mortality of bees, while chlorsulfuron 75% WG killed 90% of the experimental bees as tested via feeding. On the other hand, agro-2, 4-D and its mixture with glycel 41% EC are moderately toxic, and mancozeb 80% WP and glycel 41% EC were slightly toxic to honeybees as compared to the positive control (dimethoate 40% EC). Suddenly, diazinon 60% EC and malathion 50% EC triggered 100% mortality of bees, while endosulfan 35% EC and chlorsulfuron 75% WG caused 63.63% and 90.82% of bee mortality, respectively, when evaluated via contact test. The fumigation test also showed that chlorsulfuron 75% WG, diazinon 60% EC, and endosulfan 35% EC caused 100%, 86.7%, and 65.6% mortality rate of bees. Our result also highlighted that tested LD50 of all pesticide incidents were significantly lower than the manufacturer-based LD50. This shows that local honeybees A. m. jemenetica are extremely sensitive to commonly used agricultural pesticides, which may affect the colony level due to the intensive application of these pesticides in Ethiopia.

Exploring the synergistic toxicity of synthetic pesticides and their impact on development and behavior of Honeybee (Apis mellifera L.)

“…Common symptoms included agitation, narcotic-like states, audible hovering, and crawling behaviors (Ali et al 2023b). Pesticide exposure disrupted bee communication and coordination within colonies, leading to heightened agitation and erratic behavior resembling a narcotic-like state (Abay et al 2023). Additionally, pesticides interfered with sensory perception, causing audible hovering sounds during navigation (Haq et al 2024).…”

“…The primary issue pertains to the persistent accumulation of pesticide residues over time, which can exacerbate the decline of species crucial for pollinating terrestrial ecosystems (Brodschneider et al 2017). Prolonged exposure of honey bees to pesticides can have a significant impact on their well-being and behavior (Anwar et al 2022;Abay et al 2023). Among the various types of pesticides that pose a threat to honey bees, neonicotinoids are particularly hazardous (Fairbrother et al 2014).…”

Characterization of Insect–Pollinator Biodiversity in Agrochemical-Contaminated Agricultural Habitats

“…They can be exposed to agrochemicals in different ways: through air particles, eating contaminated food (nectar or pollen), and consuming contaminated water [4,10,29]. Exposures to agrochemicals could lead to INPOs' mortality [5,9], changes in diurnal activity patterns, e.g., foraging behavior, navigation, and visitation frequency, and other sublethal impacts (Table 2). In addition, it has been shown that a number of agrochemicals, including neonicotinoids, and chlorpyrifos, can severely damage INPOs' nervous systems and irreversibly impair their immune systems, which eventually decreases their biodiversity [15,23,25,30].…”

“…In diverse ecosystems, encompassing agricultural and protected habitats, insectpollinators (INPOs) are essential invertebrates as they promote biodiversity preservation and the health of ecosystems [1][2][3][4]. INPOs are crucial for the pollination services [5,6], as they support the sustainability of countless flowering plants, such as crops, trees, bushes, herbs, vegetables, and many more [7]. They improve agricultural productivity, enhancing human nutrition and food security through pollination services [1].…”

Insight into Olfactory Learning, Memory, and Mortality of Apis mellifera jemenitica after Exposure to Acetamiprid Insecticide

“…Agrochemicals are highly toxic and have rapid knockdown effects against insects, including pollinators at lethal or sublethal concentrations [17]. Lethal effects due to acute exposure to insecticides cause immediate honey bee mortality [18]. Sublethal concentrations can cause impairments to navigation and foraging abilities, communication, reduced learning and memory, and altered reproductive success in honey bees [19][20][21].…”