All posts by SETAC Student Outreach

SETAC SNA Student Survey: COVID-19 Impacts

The global COVID-19 pandemic has impacted almost all facets of our lives. The SETAC North America Student Advisory Council (NASAC) is surveying students to see how these impacts have affected their coursework, funding, research, and overall wellness.  Please take the time to complete this 5-10 minute survey designed to give students a voice – a place where they can share their experiences, both positive and negative, and amplify their concerns and opinions. We hope that the data you generate will be useful in promoting the interests of students within our organization and beyond.

Link to Survey: https://www.surveymonkey.com/r/?sm=eq8mi_2FMd7hKHUKbR3GVfRg_3D_3D

An Update from the Northern California (NorCal) Regional Chapter

The NorCal Regional chapter has highlighted a few updates in their most recent newsletter, detailing their student scholarship winners, their most recent scientific showcase, and announcing their upcoming virtual meeting.

Congratulations to the Undergraduate and Graduate Scholarship Awardees!

These award winners have submitted proposals pertaining to their scientific research which have been selected for NorCal’s student scholarship. With these awards, the winners will be able to fund their pilot projects and travel to research sites or other labs.

Nicole Egan, the undergraduate award recipient, submitted a proposal for an exposure study of Daphnia magna to environmentally relevant concentrations of Imidacloprid, an insecticide.

Aaron Ninokawa, the graduate award recipient, has submitted a proposal to develop a method to decouple the normally highly correlated components of the dissolved carbonate system to identify specific chemical components that most influence calcium carbonate shell formation in some representative bivalves.

Science Showcase

In June 2020, NorCal has hosted a virtual meeting on a video conferencing platform, during which 10 presenters have each introduced their research in a 3-minute window, followed by a 1-2 minute Q&A. These presentations covered topics such as “pesticide research on bats and aquatic communities, detection and impact of microplastics, potable use of effluent and runoff, zinc deficiency and the prevalence of autism, as well as policy perspectives and an optimistic look into the future.” This meeting instigated further discussion and networking opportunities as a result.

29th Annual NorCal SETAC Virtual Meeting

This year, NorCal will continue to host their annual meeting, but on a virtual platform for the first time. During this meeting, NorCal will host a virtual short course titled “Navigating the Intersection of Science and Policy in California: A #SciPolCommWorkshop,” on the 1st day, hold a lecture on the research of their Plenary Speaker Dr. Marjorie Brooks, Associate Professor from the Department of Zoology at Southern Illinois University, on the 2nd day, and leave the 3rd and 4th day for presenters to discuss their research live. Their meeting will be held on September 21 – 24, 2020. Be sure to submit an abstract by Aug 7, 2020, if you are part of the Northern California Regional Chapter.

Check out the NorCal Newsletter by following this link: https://mailchi.mp/e1bb8569cf5e/norcal-setac-newsletter-july-2020

The Prairie Northern Chapter (PNC) of SETAC 2020 Virtual Student Video Competition

The PNC has decided to hold a virtual student competition to replace their annual meeting this year in order to maintain social distance while keeping their members connected to each other. The Abstract Book is on their website.

Congratulations Winners!

PhD

1st PlaceAndrew Nagel – Chronic toxicity of waterborne thallium to Daphnia magna

2nd Place: Lauren Zink – Laundry-effluent toxicity of copper-treated textiles to freshwater invertebrates

3rd Place (tie): Derek Green – Toxicokinetic modeling of selenium in fathead minnow orally exposed to selenomethionine

3rd Place (tie): Razmara Parastoo – Mechanism of copper nanoparticle toxicity in rainbow trout olfactory sensory neurons

Msc

1st PlaceTyler Black – Fresh diluted bitumen and a shoreline oil cleaner impair water striders under environmentally realistic conditions

2nd Place: Annika Mangold-Döring – A Novel Multi-Species Physiologically-Based Toxicokinetic Modelling Approach in Support of Chemicals Risk Assessment

3rd Place: Rebecca Eldridge – Arctic Ecotoxicology: A Critical Review to Break the Ice

Undergraduate

1st PlaceDarren Van Essen – The novel brominated flame retardant, 1,2,5,6-tetrabromocyclooctane (TBCO), impairs oocyte maturation in zebrafish (Danio rerio)

2nd Place (tie): Kaden Fujita – 1H NMR based metabolomic profiling of early life stage zebrafish (Danio rerio) exposed to weathered sediment-bound diluted bitumen

2nd Place (tie): Danielle Desrochers – Characterizing the impacts of diluted bitumen spill remediation methods on freshwater benthic macroinvertebrates using shoreline enclosures

Sarah Wallace

Who is Sarah?

I am a Ph.D. Candidate in water sciences at the Institut National de la Recherche Scientifique (INRS), Centre Eau Terre Environnement, in the beautiful & old Quebec City, Quebec, Canada.

What’s her research on?

I use ecotoxicogenomic (ecology + toxicology + ‘omics) tools to study the sublethal effects of polycyclic aromatic compound exposure in birds.

Why is it important?

Polycyclic aromatic compounds are ubiquitous in the environment from both pyrogenic (e.g., industrial processes) and petrogenic (e.g., petroleum products) sources and yet we know very little how they affect embryonic development. I will use the large scale ‘omics data to better understand the mechanism of action and to find biomarkers that could be used to predict exposure and effect.

What’s the most fun/rewarding part?

Working with wildlife can be unpredictable both during fieldwork and with molecular lab work, but I love the challenge! I also really like searching for patterns in big datasets because it is like putting together a puzzle.

Sarah is also a managing editor of the fieldwork blog Dispatches from the Field where
she regularly posts the stories that
don’t make it into scientific papers!

Derek Green

Hi all,

It felt somewhat obtuse to provide an April blog post about the present state of our science without addressing current events, so I hope you’ll permit me to stray slightly off the beaten path with this one. What we are collectively experiencing is largely unprecedented in living memory and will certainly leave a lasting cultural shadow. My deepest sympathies extend to those who may have been more personally affected by the COVID pandemic, and I empathize with those who are simply having a difficult time dealing with these unexpected and unusual circumstances. While the steps we take now and in the near-term future are predictably uncertain, the collective global precautionary response should encourage us all and has done well to put us on a path towards normalcy. Though the duration and outcome of this journey are still uncertain, we can undertake it confidently knowing we are all embarking upon it together. In the meantime, I encourage you to make use of this time as you can, take time for yourself as you need, and to keep looking forward to a return to those things that always drove you to be where you are. I, for one, can’t wait to get back on the water.

All the best, and be well.

Derek

Key words: optimism, progress, resilience

Alexandra Folcik

SETAC_photo blog picture

Who is Allie? I’m a PhD student in Toxicology at Texas A&M University, Go Aggies!

What’s her research on? My project focuses on the use of electron beam (eBeam) irradiation technology to remediate algal toxins in drinking water.

Why is it important? Rising temperatures and nutrient pollution are increasing the occurrence of harmful algal blooms around the world. When people or animals drink water that comes from a water source containing an algal bloom, they have the potential to ingest toxins, many of which can damage your brain or your liver. Therefore, it is important to find effective ways to get rid of these toxins and organisms from drinking water plants to prevent exposure.

What’s the most fun/rewarding part? The most rewarding part of my research is being able to bridge the gap between so many different disciplines such as engineering, chemistry, and toxicology. The work I am doing has direct applicability to real world problems and could someday be implemented into treatment processes to make the world a healthier place.

Allie has a science highlight on Instagram to talk about her experiments (follow her @ayohkay12)! She is also active on LinkedIn.

Niranjana Krishnan

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Who is Niranjana? I’m a PhD candidate at Iowa State University, which is located in a small but beautiful city called Ames.

What’s her research on? I am studying how agricultural insecticides affect monarch butterflies.

Why is it important? Monarch butterfly populations have been declining and studies have shown that to sustain the eastern monarch population in North America, it is essential to plant milkweed (which is the only plant the monarch caterpillars eat) in agricultural areas in the Midwest. Hence it is important to know how insecticides used in fields harm monarchs so we can plant milkweed in the right locations!

What’s the most fun/rewarding part? I am lucky enough to be one of the few labs which has year-round monarch rearing capabilities — not many people can work on the project I am working on! This makes the data I collect novel. It also helps that federal regulatory agencies, environmental groups, and agrochemical companies are interested in my work.

More details on her research can be found here!

Leah M. Thornton Hampton

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Who is Leah? I’m a PhD candidate at the University of North Texas, though I spend the majority of my time at Texas Christian University!

What’s her research on? My dissertation project is focused on the role of thyroid hormones during the development of the immune system. I’m particularly interested in the potential effects of early life stage thyroid suppression (too little thyroid hormone) on an organism’s ability to defend itself against infections when it is an adult!

Why is it important? It’s important for us to understand how thyroid hormones may impact the immune system because most systems are constantly influencing one another. In other words, we have to understand basic physiology before we can add layers of complexity like how environmental thyroid disruptors may negatively impact the immune system.

What’s the most fun/rewarding part? One of the most challenging/most rewarding parts of my dissertation so far has been tailoring cellular assays to work in my model organism (the fathead minnow). Here you can see me at the microscope counting hundreds of cells as part of this process – tedious, but totally worth it to get the data!

Here are results from her ‘preliminary work’ that inspired this research!

Simplifying ecotoxicology studies with model species: Are organisms in the North hemisphere the same as the organisms from the South?

By Fernando Gastón, Iturburu* and Lidwina, Bertrand*.

Endings are a great opportunity to reflect on past decisions. As both of us wrap up our PhDs in Ecotoxicology (Fernando at the National University of Mar del Plata and Lidwina at the National University of Córdoba, both in Argentina), we keep thinking of the questions we struggled with as students and the conclusions we reached. One of the biggest questions in our research was: is it better to work with native species or model organisms to examine research questions pertaining to aquatic environments in South America?

Blogpic-1

Model organisms are simple organisms expected to behave similarly to other organisms when exposed to potentially harmful chemicals. Traditional model species include zebrafish (Danio rerio), aquatic macrophytes of the Myriophyllum and Lemna genera and planktonic crustacean as Daphnia magna among others (Häder and Erzinger, 2018). Model species are well studied, so a lot is known about how to keep them happy and healthy in a laboratory setting. But, most benchmark testing for model organisms was developed in the northern hemisphere, particularly more socio-economically developed countries like the USA, China, Germany, UK, and Canada. Since different species are known to have different sensitivities to toxic compounds (Van der Oost et al., 2003), it is questionable whether or not model organisms can act as representative samples for environmental studies concerning environments in the southern hemisphere.

Our research was concerned with conducting experiments to understand the potential negative impacts of metals and pesticides on South American, particularly Argentinian, aquatic ecosystems. These chemicals can enter the environment from industrial activities such as metalworking, tanneries, litter bins, open sky mega-mining with tons of rocks extracted each year, and large- scale agricultural production which are all common throughout South America. We had several questions while designing our research experiments:

1- Are native species useful (like model ones) to assess environmental degradation through biomonitoring programs?

2- Are studies carried out using species from European or North American countries representative of the sensitivity of species present in ecosystems from others regions of the world?

3- Are the established guidelines developed with model organisms “good” enough to protect species from South American ecosystems?

4- Could we develop our own guidelines with native species?

We were ultimately swayed to using multiple local species (shown in Figures 1 and 2) because we believe, along with the experts of the OECD (Organization for Economic Co-operation and Development, 2002), that multiple indigenous test species provide more robust results for resolving regional environmental concerns.  But this decision came with several advantages and disadvantages. Let’s start with the “worst” part of the story, the disadvantages of working with native species:

– The first problem is the absence or low availability of basic information about your object of study. Since no one else is studying them, there’s a lot more uncertainty in understanding how chemicals affect them. There is also little information about how to keep them healthy in a laboratory setting so it is hard to say if observations are caused by chemicals or just abnormal living conditions. Resolving this concern involves a lot of time, money, and resources (which are sparse when you’re a PhD student!) which can limit your experimental design and, sometimes, lead to make mistakes or to obtain non “suitable” results.

– Other problem arise when you try to publish your first paper and reviewer’s comments arrive in your inbox. Comments reflect great distrust in your results, even if standardized protocols were applied, because you are not using a model species. This leads some reviewers to doubt the usefulness of your research because is not a world recognized model and concern.

Blogpic-2

 

Figure 1- Australoheros facetus is a cichlid fish which inhabits the Parana’s basin in Brazil, Paraguay, Argentina, and Uruguay. It is a suitable and sensitive fish species to assess pesticides pollution in South American ecosystems. Ph: Fernando G. Iturburu.

But not everything is negative when you chose a native species to join you and your Ph.D. thesis for three or five years. Several advantages to using native species are:

– Usually, the “native” characteristic allows for better availability and accessibility to organisms for experimental tests. They don’t have to be shipped too far, and could even be collected close to your lab!

– You can avoid the introduction of exotic organisms into local waters when conducting field studies with foreign model organisms, which has the potential to cause serious ecosystems disorders.

– The lack of information about native species can also be considered a positive: ALL is new and the obtained information will improve the understanding of the sensitivity of these species and related ones, and how regional ecosystems would be affected in presence of pollutants. New biological mechanisms and responses can be found and published but, again, tips about how to communicate your research work are crucial! You must convince reviewers that non-model species results represent a novelty important for advancing global ecotoxicological knowledge.

– Results from native species studies would be considered for the selection of new, region-specific model species to use in the establishment of environmental guidelines of studied region, which could improve the protection of aquatic ecosystems.

When comparing results from our research to the existing body of literature, we found the advantages to outweigh the disadvantages. The literature describes that the LC50 (concentration at which 50 percent of organisms in a study exposed to a compound die) for the neonicotinoid insecticide imidacloprid in model fish is around 200 mg L-1 (IUPAC PPDB, 2018). Nevertheless, for the South American cichlid fish Australoheros facetus (Figure 1), we found that the LC50 value was much less: below of 10 mg L-1 (Iturburu et al., 2017)! Even more, this compound causes DNA damage from concentrations of 1 μg L-1 (Iturburu et al., 2018, remember that 1 microgram (μg) is a millionth part of 1 gram).

Figure 2- Palaemonetes argentinus represents a small decapod from water ecosystems of South America. Its sensitivity to pollutants exposure as well as its ecological relevance in trophic chains and, ecosystems, led to it being proposed as a possible bioindicator of environmental quality. Ph: Lidwina Bertrand.

We also found interesting results with respect to variability in sensitivity across organisms. For example, the Argentinean Environmental Water Quality Guidelines (AEWQG, 2003) recommends concentrations of the widely used insecticide chlorpyrifos (CPF) should not exceed 6 ng L−1 (being 1 nanogram, ng, a billionth part of one gram) for the protection of aquatic biota. This limit comes from experimental results with model species from others world regions. Nevertheless, the shrimp Palaemonetes argentinus (Figure 2) and the macrophyte Potamogeton pusillus showed significant response of studied biomarkers after 96hs of exposure at 3.5 ng L−1! In the case of the shrimp, several biomarkers responded significantly at 3.5 ng L−1 CPF, including metallothionein concentration (decreased), acetylcholinesterase (inhibited) and antioxidants enzymes (induced) activities; while in the macrophyte chlorophylls contents dropped in described conditions (Bertrand et al., 2016 and 2017). Usefulness of native species as bioindicators of water pollution was evidenced using them in river monitoring campaigns (Bertrand et al., 2018 a, b).  So, all these results (and many others) which show that different species can still be affected at different concentrations of a chemical, even below an accepted limit, telling us that species selection in ecotoxicology testing is very important.

Thus, the native species have a lot of information to bring us, and from our place (and with all necessary considerations) we will continue to promote the use of these organisms to understand the possible effects of pollution in South American and others ecosystems. And maybe one day (who knows!), we will be able to have our own model species and guidelines.

 

 

Blogpic-5Iturburu, Fernando Gastón obtained his Ph.D. in Biological Sciences at the National University of Mar del Plata, Argentina. His research focused on the effects of current use pesticides on two South American freshwater species: a cichlid fish (Australoheros facetus) and a macrophyte (Myriophyllum quitense). The thesis aimed to study different biomarkers of these organisms experimentally exposed to pesticides, as well as study factors which could modify the interpretation of these responses. As an ultimate goal, the project aimed to establish these organisms as freshwater bioindicators in South American aquatic ecosystems. Publications from PhD thesis can be found in:

https://www.researchgate.net/profile/Fernando_Iturburu

E-mail: fernando.g.iturburu@gmail.com

 

Blogpic-6Bertrand, Lidwina obtained her Ph.D. in Biological Sciences at the National University of Córdoba, Argentina. Her research focused on the usefulness of two South American native species, a small shrimp (Palaemonetes argentinus) and a rooted macrophyte (Potamogeton pusillus), as freshwater bioindicators. The thesis involved firstly the study of biomarkers responses in mentioned organisms exposed to environmentally relevant concentrations of pollutants (metal and pesticide) laboratory conditions. Experiments involved exposure concentrations lower than those suggested by Argentinean environmental guidelines. Finally, organisms were used in an active monitoring with the aim to analyze their sensitivity in sites with complex mixture of pollutants associated with different land uses in the Ctalamochita River Basin as a case of study.  Publications from PhD thesis can be found in:

https://www.researchgate.net/profile/Lidwina_Bertrand

E-mail: lidwinabertrand@gmail.com

 

References

– AEWQG (Argentinean Environmental Water Quality Guidelines), 2003. Subsecretaria de Recursos Hídricos de la Nación, República Argentina.

– Bertrand, L., Monferrán, M.V., Mouneyrac, C., Bonansea, R.I., Asis, R., Amé, M.V., 2016. Aquat. Toxicol. 179, 72–81. http://dx.doi.org/10.1016/j.aquatox.2016.08.014

– Bertrand, L., Marino, D.J., Monferrán, M.V., Amé, M.V., 2017. Environ. Exp. Bot. 138, 139–147. https://doi.org/10.1016/j.envexpbot.2017.03.006

– Bertrand, L., Monferrán, M.V., Mouneyrac, C., Amé, M.V., 2018a. Chemosph. 206, 265–277. https://doi:10.1016/j.chemosphere.2018.05.002

– Bertrand, L., Monferrán, M.V., Valdés, M. E., Amé, M.V., 2018b. Env. And Exp. Bot. Under revision.

– Häder, D. P. and Erzinger, G. S., 2018.  Bioassays: Advanced Methods and Applications. Elsevier. https://doi.org/10.1016/B978-0-12-811861-0.00031-0

– Iturburu, F.G., Zömisch, M., Panzeri, A.M., Crupkin, A.C., Contardo-Jara, V., Pflugmacher, S., Menone, M.L., 2017. Ecotoxicol. Toxicol. Chem. 36(3), 699-708. https://doi.org/10.1002/etc.3574.

– Iturburu, F.G., Simoniello, M.F., Medici, S., Panzeri, A.M., Menone, M.L., 2018. Bull. Environ. Contam. Toxicol. https://doi.org/10.1007/s00128-018-2338-0.

– International Union of Pure and Applied Chemistry (IUPAC). PPDB: Pesticides Properties DataBase. University of Hertforshire, Hatfield, Hertfordshire, UK. [cited 2018 April 19]. Available from: http://sitem.herts.ac.uk/aeru/iupac/atoz.htm.

– OECD (Organization for Economic Co-operation and Development). Testing guidelines. Available from: http://www.oecd.org/env/ehs/testing/

– van der Oost, R., Beyer, J., Vermeulen, N.P.E., 2003. Environ. Toxicol. Pharmacol. 13, 57–149, http://dx.doi.org/10.1016/S1382-6689(02)00126-6.

Why we Need a Science-Based Approach to Help the Monarch Butterflies

By Niranjana Krishnan

I will start by acknowledging this: I am lucky to be working with monarch butterflies. Not only are they fascinating and beautiful, very few labs in the country have colonies to run year-round bioassays. At Iowa State University, where I am a PhD student, the colonies are maintained by the U.S. Department of Agriculture (USDA).

monarch butterflies
USDA’s monarch butterfly colony in Ames, Iowa

There are several factors that make monarchs captivating species: their four-stage life cycle, their annual passage across North America, their reproductive diapause (i.e., suspension of mating) before migration to overwintering sites, and so on. As you can find all this information easily online, I will stick to something which isn’t written or published anywhere (yet!): my research. I assess the risks of insecticide exposure on monarch butterfly larvae. Before I delve more into this exciting work, I would like to explain why it is important and what can be achieved with this research.

In the US you see two major migratory populations, one to the east of the Rocky Mountains and the other to the west. Both populations have declined by nearly 80% in the last two decades¹. In response to this, U.S. Fish and Wildlife Service (USFWS) was petitioned to list the monarchs as endangered species. The agency will come up with a listing decision in June 2019², but in the meantime released a working document that stressed the need to know risks of insecticide exposure on the butterfly³. The decline also made then President Obama specifically include monarch butterflies in his Pollinator Memorandum, where he tasked the U.S. Environmental Protection Agency (USEPA) and USDA to restore their populations⁴. One of the major reasons for the butterfly decline is believed to be the loss of milkweed⁵- the only food the caterpillars eat. Thus, conservation efforts are focused on planting milkweeds, especially in Iowa and the neighboring Midwestern states, which form the summer breeding grounds of the eastern monarch migratory population. As these states also have large swaths of land devoted to agriculture where insecticides are often used, there is a concern that planting milkweeds in such landscapes could negatively impact larval survival and adult recruitment. Because of this concern, USDA issued a guideline discouraging milkweed establishment within 125 feet of insecticide-treated crop fields⁶. For a representative county in Iowa, we found that this ‘no plant zone’ would exclude over 80% of rural roadside rights-of-ways and nearly 40% of non-crop lands. That is a lot of area being lost where potential habitat could go. And unfortunately, there is very little monarch toxicology or exposure data to know at what distances to plant milkweeds away from insecticide-treated fields.

And that’s what my lab is trying to find out! We selected insecticides commonly used in corn and soybean fields, as they are the predominant crops grown in the midwestern states. Our six representative insecticides cover four different groups based on modes of action: pyrethroid, organophosphate, neonicotinoid and anthranilic diamide. In corn and soybean fields, these insecticides are either sprayed or coated on the seeds. If they are sprayed, they can drift and land on nearby milkweeds or larvae. If they are coated on seeds, they can leach into the soil and be absorbed by milkweeds downslope of the crop field. Thus larvae can be either directly exposed to insecticides through their cuticle or indirectly exposed by consumption of milkweed leaves. Our toxicology bioassays mimic these two routes of exposure.

To figure out at what distances to plant milkweeds from crop fields, we are doing the following:

  1. Determining the toxicity of insecticides on the larvae by generating dose-response curves, i.e., finding concentrations that cause a spectrum of mortality (0% to 100%).
  2. Estimating exposure concentrations that the larvae are likely to face at different distances from treated fields (the further away they are, insecticide exposure will decrease). We rely on computer models and field studies to obtain this information.
  3. Using the dose-response curves and exposure estimates to calculate larval percentage mortality at different distances away from the field. This is called a patch-scale risk assessment.
  4. Incorporating the above information into an agent-based model⁷ to see how the monarch population responds at the landscape level. This is called a landscape-scale risk assessment and it is more realistic and informative than a patch-scale risk assessment since monarch butterflies fly across the landscape and lay one or two eggs on milkweed stems here and there. They don’t lay all their eggs in one basket!

The final step can help answer questions like how many monarchs would be produced with and without a ‘no plant zone’ (125 feet or otherwise) over a ten-year period in Iowa. Based on our data, the habitat placement option that produces the most monarchs can hopefully be implemented on the ground.

So far, we have obtained comprehensive results for spray applications where the insecticide directly lands on larvae. Based on our toxicology studies, pyrethroid (beta-cyfluthrin) and anthranilic diamide (chlorantraniliprole) insecticides cause the greatest mortality, followed by organophosphates (chlorpyrifos). Neonicotinoids (imidacloprid and thiamethoxam) cause negligible mortality, especially to older larvae. The larval mortality away from the field is much greater if the insecticide is applied via an aircraft as compared to ground applications⁸. Based on our landscape modeling data so far, more adult monarchs are produced by planting milkweeds in all available space as compared to scenarios with 125 feet ‘no plant zone’ around corn and soybean fields, even with the larval mortality due to spray drift⁹. Our ongoing studies are looking at how larval consumption of milkweeds that contain insecticides can influence monarch production and inform options for placement of new habitat.

krishnan

 

Niranjana Krishnan is obtaining a doctorate degree in toxicology from the entomology department at Iowa State University. She is a student member of Iowa Monarch Conservation Consortium (https://monarch.ent.iastate.edu/).

 

References:

  1. Brower L.P., Taylor O.R., Williams E.H., et al (2012) Decline of monarch butterflies overwintering in Mexico: Is the migratory phenomenn at risk? Insect Conserv Divers 5:95–100.
  2. https://www.fws.gov/savethemonarch/SSA.html
  3. https://www.fws.gov/savethemonarch/pdfs/Monarch.pdf
  4. https://obamawhitehouse.archives.gov/blog/2015/05/19/announcing-new-steps-promote-pollinator-health
  5. Flockhart DTT, Pichancourt JB, Norris DR, Martin TG (2015) Unravelling the annual cycle in a migratory animal: Breeding-season habitat loss drives population declines of monarch butterflies. J Anim Ecol 84:155–165. doi: 10.1111/1365-2656.12253
  6. National Resources Conservation Service (NRCS) Monarch Butterfly Wildlife Habitat Evaluation Guide (2016)
  7. Grant T., Parry, H., R., Zalucki, M.J., and Bradbury, S.P. (2017) Predicting monarch butterfly movement and egg laying with a spatially-explicit agent-based model: The role of monarch perceptual range and spatial memory. Ecological Modelling (Submitted).
  8. Krishnan, N., Bidne, K., Hellmich, R., Coats, J. and Bradbury, S.P. (2017) Risk assessment of insecticides commonly used in corn and soybean production on monarch butterfly (Danaus plexippus) larvae.  Society of Environmental Toxicology and Chemistry North America 38th Annual Meeting. November 12 -16, Minneapolis, MN (Abstract ID# TP106).
  9. Bradbury S.P., Grant, T.J., Krishnan, N. (2017) Landscape Scale Estimates of Monarch Butterfly (Danaus plexippus) Population Responses to Insecticide Exposure in an Iowa Agroecosystem. Society of Environmental Toxicology and Chemistry North America 38th Annual Meeting. November 12 -16, Minneapolis, MN (Abstract ID# 182).