Location: Southern Horticultural Research Unit
Project Number: 6062-21430-004-037-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Nov 1, 2023
End Date: May 1, 2025
Objective:
The main objective of this project is to enhance the health of bees in the Mid-Western Arkansas region. This will be achieved through a comprehensive study of various interactive environmental threats, as well as by developing integrated strategies to conserve and augment their population within this region.Bees play a vital role as pollinators for a wide range of both wild and cultivated crops. Within commercial crop production systems, these essential pollinators frequently encounter a variety of agricultural chemicals, which present significant threats to their survival. Prolonged and repeated exposure to such agricultural chemicals can potentially disrupt abundance of bee populations over time. Exposure to pesticide chemicals can also impact individual bee health in longer term, by disrupting their gut microbiome and immune system.
Current research efforts have predominantly concentrated on the health of honey bee populations, neglecting the comprehensive study of other bee species. Given the crucial ecosystem services that several native bees provide, it is imperative to undertake both laboratory and field studies assessing the toxicological risk associated with a spectrum of pesticides and their mixtures, as used in the agricultural and urban settings, specifically focusing on their potential sub-lethal impact on different species of native and managed bees. The main objectives of this project are: 1) to examine major environmental stressors impacting bee health in different ecosystems in mid-western Arkansas region, 2) to develop baseline toxicity information of various pesticides used in agricultural and non-agricultural systems to various species of bees, 3) to determine impact of interactive stressors on native and managed bee species, 4) to develop strategies to mitigate ecotoxicological risk associated with pesticide applications to bees.
Approach:
Obj. 1: A field study will be conducted by employing different sampling techniques including trap-nests, vane traps, and pan traps in various locations and ecosystems within the mid-western Arkansas region. Samples of bees will be collected from passive traps, and samples of pollen masses, nest substrates, and developing bee stages from trap-nests. In the laboratory, these collected samples will be processed and samples will be outsourced for analysis concerning pesticides and pathogens.
Obj. 2: Various lab studies will be conducted to develop baseline information of pesticide toxicity to three bee species (viz. blue orchard bee/mason bee, leafcutter bee, and bumblebee). Common formulated pesticides (and their mixtures) that are currently used in agricultural and non-agricultural systems (for pest management) will be assessed via multiple and replicated contact and ingestion bioassays. In regard to each species, relative LD50 and LC50 values of each treatment will be determined.
Obj. 3: Lab and field studies will be conducted to assess the impact of interactive stressors on native and managed bee species. Various field-realistic pesticide exposure scenarios will be simulated in lab and semi-field environment, and impact from such exposures independently as well as in combination with other stressors such as nutrient quality, extreme temperatures, common pathogens, will be assessed for each bee species. Responses of male and female mason bees and leafcutter bees will also be assessed. Observations will be recorded for an extended period of time (96 hours) after exposure.
Obj. 4: Based on the findings from Objectives 1-3, an integrated strategy utilizing modified bee habitat will be developed to mitigate field-realistic risk of pesticide exposure to various bee species. Different locations within the study farm will be selected for this multi-year field study. Modified bee habitat will include native flowering planting with season-long flowering duration and high nectar and pollen contents will be used in the study and its potential to mitigate impact of interactive stressors will be determined.
