Final report for GNC20-305
Project Information
Economic Impacts of Bats in Dakota Agroecosystems: Do Insect-Eating Bats Reduce Pesticide Needs and Contribute to Plant Pollination?
Insectivorous bats play a key role in regulating insect communities. Yet, severe population declines in North American bat populations, due to a fungus that causes White-Nose Syndrome, may impact the ecological and economic roles bats play in natural and agroecosystems. This project aims to quantify the dietary composition of bats in North and South Dakota. Specifically, by 1) evaluating predation upon common crop pests, 2) assessing bats’ economic value as natural agents of pest removal in agroecosystems, and 3) examine if bats indirectly contribute to pollination. The Dakotas are considered agricultural states, with a combined total of 40.4 million acres harvested during the 2017 USDA Census, making research related to Dakota bat impacts essential. To achieve project goals, a morphometric microscope and DNA-based analysis of previously collected fecal samples will be completed. This involves PCR amplification of prey DNA followed by molecular cloning to enable gene sequencing.1 Such DNA-based techniques can detect prey items that are not visible under a microscope and identify prey species to a much finer taxonomic level.1 Similar methods will be used to detect pollen, which may have been on prey items consumed by bats, to address contributions to pollination. Findings could potentially assist farmers with decisions about timing and intensity of pesticide applications. If there is evidence for indirect pollination, this information would not only apply to agroecosystems, but all ecosystem types found across the Dakotas. Overall, this study will significantly contribute to understanding the ecological services bats provide, especially in environments dominated by agriculture. Furthermore, understanding population level differences in dietary needs can provide managers with critical information, allowing them to key in on the protection of resources that are important to local bat populations. Outreach emphasis will be placed on educating farmers and exposing primary and secondary school children to current bat research. Explaining bats roles within agroecosystems will promote interest in the conservation of bat species and their habitats. Recently, due to the COVID-19 pandemic, attitudes towards bats have been at an all-time low. Educating the public about the positive services bats provide could lead to a shift from the current negative conceptions.
- Hope, P.R., et al. (2014). Frontiers in Zoo., 11(1), 39
The audience we are attempting to reach is the general public, with emphasis placed on educating primary and secondary school children and those working in the agricultural industry. Exposing primary and secondary school children to current bat research will promote interest in the conservation of bat species and their habitats. Since approximately 47% of Dakota land is used for agricultural purposes1, educating farmers about the ecological and economic impacts of bats is essential. Recently, attitudes towards bats have been at an all-time low due to SARS-CoV-2 and resulting COVID-19 pandemic, likely originating from a horseshoe bat.2 A recent ABC news article discusses multiple incidents involving humans shooting bats due to the public’s fear of viral disease spread and misconception that all bats carry viral diseases.3 Educating the general public with facts about the positive services bats provide could lead to a shift from the current negative conceptions. Economically, findings would be relevant to farmers deciding when and at what intensity to apply pesticides. Previous studies have shown bats remain economically impactful even when pesticides and genetically modified crops are used.4 Furthermore, findings could lead to identification of ideal spray intervals, preventing the overuse of chemical pesticides, and curb insect resistance.4 If findings suggest indirect pollination, results could be important not only within agroecosystems, but all Dakota ecosystem types.
- Census of Ag. (2017). USDA, 1, 1-711
- Andersen, K., et al. (2020). Nat. Med., 89, 44–48
- Tuffield, R., et al. (2020). ABC News.
- Federico, P., et al. (2008). Ecol. Appl., 18(4), 826-837
Cooperators
- (Researcher)
Research
To achieve the goals of this project, a DNA-based analysis of 583 fecal samples collected during the 2016-2019 field seasons has been completed. Prey DNA was extracted from collected guano samples using Quick-DNA Plant/Seed Miniprep Kit and protocol (Zymo Research, USA). The following primer set 1) LCO1490/HCO2198 and 2) C_LepFolF/C_LepFolR were used to identify extracted prey DNA from collected guano samples. Both primer sets are considered "universal" primers but LCO1490/HCO2198 is a more generic arthropod primer with wider taxonomic coverage1 whereas, C_LepFolF/C_LepFolR has been shown to better detect some prey orders (i.e., Arachnida).2 Results from the 583 Sample were entered into NCBI nt nucleotide sequence database using the Basic Local Alignment Search Tool (BLAST; ncbi.nlm.nih.gov) to identify the prey within each sample. Anything that met a sequence similarity threshold of ≥ 98% identification (i.e., ≥ 98% chance of species identified from the DNA sequence is correct) was accepted. Of the 583 samples collected, 207 samples met this accepted standard. Represented within the final dataset are 14 orders, 75 families, 135 genus, and 248 species.
As some samples indicated multiple insect species, some of which belong to different genus or family, identification confidence levels were created, similar to methodology outlined in Razgour et al.3 The identification confidence levels are as follows:
- Solid Match – Species Level
- ≥98% Seq ID match and found in North or South Dakota.
- Match – Species Level; Match – Genus Level; Match – Family Level; Match – Order Level
- ≥ 98% Seq ID match and found in a state or Canadian territory adjacent to ND or SD.
- Non-Match
- Is not found within ND or SD or in adjacent States or Canadian territories.
Two threshold level assignments were created: 1) Individual Data Point Level Assignment and 2) Sample Level Assignment. Under the Individual Data Point Level Assignment, each individual row of data is treated as its own sample point and assigned to one of the previously defined identification confidence levels. Under the Sample Level Assignment, all rows of data within a sample are collectively assigned to an identification confidence level. If more than one species was identified within a sample the following methodology was utilized:
- Primer set separation of data within sample - (HCO/LCO & LepFolF/LepFolR)
- Data identified by different primer sets are combined and treated as their own sample.
- Identified species not found within ND or SD or in adjacent States or Canadian territories are treated as a non-match and not included as part of the sample.
- Samples are then assigned to one of the identification confidence levels previously defined.
To address the possibility of indirect pollination, a DNA-based analysis was used to detect pollen and/or seed within the collected guano samples. We extracted DNA using a Zymo Quick-DNA Plant/Seed miniprep kit. The research lab at UTTC was shut down due to COVID-19 restrictions and DNA samples were sent to Functional Biosciences for analysis.
To assess bats agricultural value Cleveland et al.'s avoided-cost approach will be used. Avoided-cost is defined as the cost humanity avoids due to the natural pest control services provided by these mammals.5-6 There are two components of cost; 1) the amount of a crops' market value lost due to the absence of bats and 2) the reduction of pesticide costs and applications when bats are present in the ecosystem. This approach was fist used to model the economic value of wetlands6 and has since been used as a method for assessing bat economic services in agroecosystems.5
- Folmer, O., et al. (1994). Mol Mar Biol Biotechnol. 3:294-299.
- DeWaard, J.R., et al. (2019). Genome. 62:85-95.
- Razgour, O., et al. (2011). Ecol Evol. 1(4):556-570.
- Taberlet, P., et al. (1991). Plant Mol Biol. 17:1105-1109.
- Cleveland, C.J., et al. (2006). Front Ecol Environ. 4:238-243.
- Woodward, R., et al. (2001). Ecol Econ. 37:257-270.
eDNA Analysis:
Samples were collected from 11 bat species in North Dakota and 13 species in South Dakota. Figure 1 shows the species captured and the number of fecal samples obtained.
A total of 321 total guano samples were sequenced. Fecal dissection and eDNA analysis revealed that the dominant insect orders consumed by bats were Lepidoptera, Diptera, and Coleoptera. Through this analysis, several destructive crop pests were identified in bat diets, including the Diamondback Moth, European Corn Borer, Corn Rootworm, and Army Cutworm. These findings emphasize the significant role bats play in controlling agricultural pests. Figure 2, shows the percent frequency of occurrence for each insect order eaten by each of the bat species. (%FO = Number of feces containing an order divided by the total occurrences of all the orders).
Geospatial Modeling:
We used past acoustic monitoring and capture data (from 2019-2021) to make conservative, moderate and liberal estimates of bat population sizes for the two predominate species, Myotis lucifugus and Eptesicus fuscus. Heat maps were created to understand the species distribution and maximum activity rate at a site across the three-year sampling period. Figure 3 shows the little brown bat heat maps based on acoustic and capture data.
Agroeconomic Modeling:
We initially focused on crop pests in our agroeconomic model, which we developed in collaboration with Dr. David Archer at the Northern Great Plains Research Laboratory. However, after analysis, Dr. Archer noted the presence of other prey species in the data, such as the Blister Beetle, which can have severe impacts on livestock and grain feeds. This discovery introduced an additional layer of complexity that is not typically considered in economic evaluations of bats' ecological contributions. We are currently working to incorporate these findings into our model to provide a more comprehensive and detailed assessment. Past studies of the agroeconomic impacts of bats are mostly extrapolated from data collected in one system (Tadarida in Texas) in which the number of bats in the environment is uniquely high. This data, in which we are studying the diets of bats in our region, are much needed to better understand geographic differences in how bats are benefitting farmers.
This robust multi-method approach underscores the ecological and economic benefits of bats in regional agroecosystems, particularly in pest management and crop protection.
Educational & Outreach Activities
Participation Summary:
Unfortunately, aspects of this project were hindered due to the COVID-19 pandemic restrictions persisting longer than expected. Finding and/or setting up outreach and education opportunities has been difficult but as restrictions lessen and new methods of outreach become available this aspect of the grant has picked up. Despite limitations, in 2021, we were able to give three in-person presentations at 4th grade classrooms in Moorhead, MN and a virtual presentation to a 2nd grade classroom. In 2022, we participated in two all day stem events, one at NDSU in Fargo, ND and one at Concordia College in Moorhead, MN, where the "Bat Researcher for a Day" workshop was conducted for multiple groups of students ranging from 7th to 9th grade. This workshop involves throwing origami bats into mist-nets to simulate bat captures in the field. Participants are given a field notebook at the start of the workshop and instructed on proper data collection and organization. Following the field simulation, discussions related to the identification of different local species and their ecological relevance are initiated, inviting further questions and discussions. This simulation workshop can be altered to fit various education levels and gives the participant a unique look inside the field of bat research. Time was dedicated towards updating and revamping workshop materials to continually grow and meet the needs of the individuals participating. New and updated materials include the North Dakota Bat Factsheet and the Research Notebook which aligns with the presented Bat Researcher for a Day PowerPoint presentation.
In 2023, our outreach efforts engaged diverse audiences across North Dakota and surrounding states. At USDA-ARS Friends and Neighbors Day in Mandan, ND, we reached around 400 attendees, sharing insights on the ecological and economic significance of bats and their role in the agro-ecosystems. At Teddy Roosevelt Family Days in Bismarck, ND, hosted by ND Game and Fish, our booth provided a hands-on STEM activity focused on bat trapping, handling techniques, and their economic importance, engaging approximately 800 youth and parents. During the Tribal College Research Symposium (TCRS), hosted by UTTC in Bismarck, we highlighted the vital role of advancing STEM knowledge at Tribal Colleges through bat research. There were over 100 participants in attendance at the TCRS from six states. Lastly, we hosted a middle school outreach program, providing 40 local students with hands-on STEM activities surround bats habitats, foraging preferences, and agricultural impact.
Project Outcomes
Economic
Because roughly 47% of land in North and South Dakota is used for agricultural purposes, it is important to know the benefits different taxa can provide to agroecosystems. Finding would be relevant to farmers deciding whether to apply pesticides, potentially leading to identification of ideal spray intervals, preventing the overuse of chemical pesticides and curbing insect resistance. From an economic perspective, this cuts chemical pesticide and labor costs associated with pesticide application. Additionally, earlier national studies provided macro-scale estimates using bat populations not found in this region.
Our model provides a robust analysis of a multi-dimensional system using local bat populations, local crop distributions, and expanded prey data, including both crop pests and non-pest species that influence agricultural and livestock health. This comprehensive approach allows for a deeper understanding of the ecological and economic impacts of bats in regional agroecosystem.
This project will significantly contribute to understanding the ecological services bats provide. If bats are found to consume insects that predate upon agricultural plants, this could assist farmers with the timing and intensity of pesticide applications. This would be environmentally impactful as chemical run off is of major concern. Understanding dietary needs can inform managers developing conservation plans for their area, focusing on the protection of resources that are important to resident bat populations.
Social
Attitudes towards bats have typically been negative, and even more so in light of the COVID-19 pandemic which was thought to have originated from a horseshoe bat.1 Educating the public with facts the shine a positive light on the services bats provide, especially within agroecosystems and economics could lead to a shift from the current negative conceptions. The could have a secondary effect that promotes the conservation of bat species and their habitat.
- Andersen, K., et al. (2020). Nat Med. 89:44-48.
As researchers primarily focused on behavioral aspects and the conservation of bats located within the Dakotas, this study has brought awareness to a service bats are potentially providing that has not previously been looked at within our area. This work is important as this information could bridge the gap between farmers and biologists, spurring future collaborations of value to the agriculture community.