Transgenic Bt crops have been a very successful tool for managing various insect pests in field crops. However, like all pest management strategies, they have both pros and cons. Dr. Dominic Reisig, from North Carolina State University, discusses the challenges of managing resistance against Bt crops, using the example of Helicoverpa zea, an important pest of both corn and cotton.
The mechanisms of exactly how mosquitoes locate their human hosts still elude the scientific community. Dr Conor McMeniman’s lab at Johns Hopkins has made advances in understanding the important role that the CO2 we exhale has to play in mosquitoes’ host-finding abilities. With the urgency of the Zika threat looming, understanding its mosquito vectors’ human-finding processes is vital to public health.
Ph.D. student, Samuel Ramsey of the vanEngelsdorp Lab took 1st place in the 4th annual 3MT competition on April 5, 2017. After much preparation and making it through the first round of competitions the week prior, he scored the top prize!
Sammy will be awarded $500 and will go on to represent UMD in the International competition in October. Here is some info on the background of the competition but without the winners for this year updated on the site.
Please offer him congratulations when you see him. We are very proud!
A piece of exciting news to welcome you back from spring break!
Natural threats among the flowers lurk. Dr. T'ai Roulston delves into the somewhat macabre world of bumble bee parasitism by conopid or thick-headed flies.
"Dr. Arnaud Martin details his research adapting the CRISPR-Cas9 gene editing system to crustaceans and butterflies, providing further evidence that supports previous findings surrounding the use of genetic tool kits found in all animals."
Ear damage? In this case, we are not talking about listening to music too loud or standing too close to the speakers at a rock concert. Instead, Dr. Galen Dively, Professor Emeritus in the Department of Entomology, has unlocked the mystery shrouding the increased dmanage to ears of corn. Read more about Dively's study here.
Post-doc Christopher Taylor (Hamby Lab), graduate student Veronica Johnson (Hooks Lab), and Professor Emeritus Dr. Galen Dively have a new publication titled, "Assessing the use of antimicrobials to sterilize brown marmorated stink bug egg masses and prevent symbiont acquisition" in Journal of Pest Science. You can read the abstract below and find the full feature here. Congratulations on your achievement!
Dr. Dennis vanEngelsdorp is one of two college employees named to Clarivate Analytics' 2016 list of Highly Cited Researchers (HCR). HCR is a comprehensive list of influential individuals in various scientific disciplines. More on the announcement can be found on the College of Computer, Mathematical, and Natural Sciences (CMNS) home page.
However, asymptomatic bees are common and can have either low or high virus loads (de Miranda et al. 2012). The story is complicated by the fact that DWV is very closely related to a series of other RNA viruses, such as Varroa destructor virus-1 (VDV-1). And the story gets even more complicated… because of recombination.
Using next generation gene sequencing, Dr. Ryabov (currently a visiting scientist at the United States Department of Agriculture (USDA) Bee Research Lab in Beltsville, MD) and his colleagues at the University of Warwick, UK, decided to characterize the virus diversity in honey bees. They found that the genome of DWV-like viruses could be divided into three functional parts, or “modules”, any of which were sometimes crossed-over between DWV and VDV. They identified three distinct types of genomes: the 100% DWV genome, and two types of recombinants formed by the association of “modules” from DWV and VDV, which they named VDV-1DVD and VDV-1VVD (Moore et al. 2011).
So what was thought to be a single population of viruses is actually a group of variants (VDV-1DVD, VDV-1VVD and DWV). Dr. Ryabov then compared the levels of each variant in honey bee pupae and associated Varroa mites. They found that individual honey bees were usually infected by a mixture of the three variants. Of the three viruses, the recombinant VDV-1DVD’s levels in honey bee pupae was highly associated with its level in associated mites. This suggests this recombinant is more efficiently transmitted between the mite and the honey bee.
When Varroa acts as a vector for the DWV, it increases the levels of viruses in contaminated colonies, causes deformities in the affected workers (Fig. 2), and overall results in increased risk of mortality of the whole colony. But what remains to be determined is whether this is caused by 1) Varroa amplifying and introducing more virulent strains of the virus and/or by 2) Varroa suppressing the honey bee immune response.
To test those two hypotheses, Dr. Ryabov exposed Varroa-naïve honey bees (collected from a Varroa-free region in Scotland) to DWV either orally (in brood food) or through Varroa mite feeding. They monitored the change in DWV diversity and loads within the host as well as changes in honey bee expressed genes to identify potential antivirus immune responses (Ryabov et al. 2014). They detected changes in expression for a number of genes associated with the immune response of honey bees while in presence of the mites. This suggests that the second hypothesis should be further explored.
This study also showed that in Varroa-free colonies (controls), honey bees had highly diverse DWV, though at low levels. When the bees were infected orally, DWV levels remained low, but the composition of the DWV strains changed compared to the controls. When bees were infected through Varroa, two outcomes would happen. Honey bees either showed low levels of diverse DWV strains, or they developed high levels of a single specific variant of DWV or very closely related variants, even though the infecting mite contained a high diversity of strains. By inoculating honey bees through injections (which simulates Varroa feeding), the researchers observed high levels of replication for the recombinant strains containing VDV-1 derived structural gene block. This suggests that these particular strains have an advantage due to the route of transmission. All of this largely supports the first hypothesis that Varroa amplifies more virulent strains of the virus.
In conclusion, this example of the shift in virulence of the DWV – from a benign and asymptomatic virus to a serious disease – illustrates the importance of the process of recombination in the generation of various strains of viruses, and how the addition of a vector, and a new route of transmission, can increase the impact of a virus by altering the relative composition of its strains.
Meghan McConnell is a Master’s student in Dennis vanEngelsdorp’s Lab. She is currently studying honey bees, with a focus on non-chemical control of Varroa mites.
Nathalie Steinhauer is a PhD candidate working in Dennis vanEngelsdorp’s Lab on honey bee health and management practices. Her projects aims to identify and quantify the effects of risk factors associated with increased colony mortality.
Bowen-Walker, P. L., S. J. Martin, & A. Gunn. 1999. The Transmission of Deformed Wing Virus between Honeybees (Apis mellifera L.) by the Ectoparasitic Mite Varroa jacobsoni Oud. Journal of invertebrate pathology 73(1), 101-106.
Highfield, A. C., A., El Nagar, L. C. Mackinde, M. L. N. Laure, M. J. Hall, S. J. Martin, & D. C. Schroeder. 2009. Deformed wing virus implicated in overwintering honeybee colony losses. Applied and environmental microbiology 75(22), 7212-7220.
de Miranda, J. R., L. Gauthier, M. Ribiere, and Y. P. Chen. 2012. Honey bee viruses and their effect on bee and colony health. In D. Sammataro & J. Yoder (Eds.) Honey bee colony health: challenges and sustainable solutions. CRC Press. Boca Raton. 71-102.
Moore, J; Jironkin, A; Chandler, D; Burroughs, N; Evans, DJ; Ryabov, EV (2011) Recombinants between Deformed wing virus and Varroa destructor virus-1 may prevail in Varroa destructor-infested honeybee colonies. Journal of General Virology, 92(1): 156–161. DOI:10.1099/vir.0.025965-0
Ryabov, EV; Wood, GR; Fannon, JM; Moore, JD; Bull, JC; Chandler, D; Mead, A; Burroughs, N; Evans, DJ (2014) A Virulent Strain of Deformed Wing Virus (DWV) of Honeybees (Apis mellifera) Prevails after Varroa destructor-Mediated, or In Vitro, Transmission. PLoS Pathogens, 10(6): 1–21. DOI:10.1371/journal.ppat.1004230
Aliens are invading the forests of the United States! Not the green, bug-eyed aliens from outer space; no we are talking about the, well… green, bug-eyed aliens from Earth. With the globalization of trade, insect introductions leading to invasive pest problems have steadily increased over the last few centuries, causing massive economic and environmental devastation in the systems where these pests permeate. These invaders are especially difficult to manage when they are pests of our native North American forest trees due to the large spatial scale associated with them, making pesticide applications impractical.
having a warmer climate than Connecticut, created an asynchronous relationship between the host (EHS) and the parasitoid (E. citrina) in Connecticut. This means that the scale and parasitoid are developing at different times of year, preventing the wasp from being able to effectively attack the scale in its introduced range. With the colder climate of Connecticut, it was hypothesized that the EHS scales developed more slowly. Wasps, as a result, would have fewer suitable 2nd instar hosts to parasitize. Dr. Abell tested this by observing scale abundance and parasitism by E. citrina at three distinct latitudes in the U.S. (Connecticut [“coldest”], Pennsylvania, North Carolina [“warmest”]), hypothesizing that he would find more parasitoid-host synchrony as he moved further south where warmer temperatures would allow for multiple generations of scales.
Ultimately, Dr. Abell did not observe any increase in synchrony between EHS and E. citrina at any of his three field sites. Instead he found continuous reproduction of EHS, and all life stages were present throughout the year. This led Dr. Abell to Japan to better understand how EHS behaves in its native range. While surveying hemlock scales and their associated parasitoids, Dr. Abell found 11 new species attacking EHS in Japan, some of which may have potential as classical biological control agents.
a wasp that is less than 1mm in length that attacks EAB eggs. Research done by Duan et al. in 2013 indicated that T. planipennisi was effectively established in Michigan and is a strong disperser. However, they observed that there was no parasitism of EAB in larger trees. In a study done by Dr. Abell, it was determined that the bark thickness was preventing this small wasp from attacking the EAB larvae. The ovipositor (egg-laying mechanism) of T. planipennisi is too short to reach the EAB larvae underneath the thick bark.
The bark was also placed in emergence chambers to collect any parasitoid wasps that emerged from the bark remnants that were missed in earlier screening. After two years of testing these methods, Dr. Abell concluded that the bark-sifting method was a more effective way to measure the rate of O. agrili egg parasitism in the field because significantly more parasitoids were recovered with this method. Invasive insects continue to attack our forests today, therefore it is very important to continue to understand and utilize biological control methods to preserve our forests. Dr. Abell continues his work on EAB biological control in the Shrewsbury lab here at the University of Maryland where he is evaluating other introduced and native parasitoids and additionally an integrated approach that combines pesticides with classical biological control methods.
About the Authors:
Olivia Bernauer is a second year Master’s student in Dennis vanEngelsdorp’s bee lab working to better understand the floral preferences of Maryland’s wild, native pollinators.
Jackie Hoban is a second year Master’s student working on emerald ash borer biological control in Paula Shrewsbury’s lab.
Kimberly Nesci, a 1996 entomology graduate and former graduate student of Dr. Galen Dively has provided over 20 years of excellent services in the world of pesticide regulation, 17 of which she worked directly in the Office of Pesticide Programs for the Environmental Protection Agency. Now, Nesci has advanced further into the pesticide sphere, accepting the position as the acting associate director for the Environmental Fate and Effects Division within the EPA.
Nesci graduated from University of Maryland with a Master of Science in Entomology. Her career started at the EPA’s Office of Pesticides as a Chemical Review Manager. A short four-years later, Nesci became a team leader in SRRD contributing her expertise to organophosphate reregistration actions/mitigations and the cancellation of lindane (a formerly common pesticide revealed to cause neurotoxic effects). After these accomplishments, Nesci joined the Registration Division as a Product Manager in the Insecticide Branch where she worked on the pet spot-on mitigation efforts, an intricate plan produced by the US-Canada Regulatory Cooperation Council to assess the risks of insect treatments on pets. Simultaneously, she served as a member of and chaired meetings for the Food and Agriculture Organization’s Panel of Experts on Pesticide Management, a group that initiated best management practices for pesticide application in developing countries.
Her resume continued to grow thereafter. Beginning in 2013, Nesci has served as Chief of the Microbial Pesticides Branch in the EPA’s Biopesticides and Pollution Prevention Division, in which she was responsible for the scientific evaluation and constructing regulations for microbial pesticides and Plant-Incorporated Protectants. Her multi-disciplinary work in this position made her an influential component on the policy making, science, and regulatory decisions on new RNA-interference-based pesticide technologies and the development of resistance to certain proteins in genetically engineered crops.
On September 19, 2016 Nesci ascended once more within the EPA by accepting a position as the acting Associate Director for the EPA’s Environmental Fate and Effects Division. The Department of Entomology is sending our best wishes to this astounding member of our alumni community. We are proud of what this Terp has accomplished and what she will continue to achieve well into the future.
On Saturday, September 18th faculty, staff, and graduate students participated in the highly successful 2016 Entomology Retreat. Talks, discussions, and delicious food were shared by all attendees and the overall consensus was that our retreat was a grand time. One of the highlights was the distribution of the Departmental Awards. If you were unable to attend the retreat, be sure to congratulate the following folks on their achievements:
Teaching Achievement Award
Great work, guys! We are so lucky to have you as part of our entomology family.
Please join us for as many as you can! Lunch will be provided for all attendees.
Brian Lovett (St. Leger Lab) was featured today on the BioMed Central Blog as part of World Malaria Day for the work that won him the Fungal Biology and Biotechnology Student Prize at the European Conference on Fungal Genetics in Paris in early April.
Check out the complete blog post here!
Brian has had a productive Spring semester overall, including talks, workshops, and posters in both Paris and Burkina Faso:
UMD Entomology's Dr. Michael Raupp and Dr. Dennis vanEngelsdorp will appear on WAMU 88.5's Kojo Nnamdi Show on Monday, April 25 at 12:30pm. They will discuss with Kojo whether the recent ban on neonicotinoid pesticides for homeowners in Maryland will help prevent the loss of Maryland's honeybees.
Be sure to tune in!
The vanEnglesdorp Lab was featured in a recent NBC Washington online post regarding a project that will attract pollinators to several stretches of Maryland highways by bringing "more milkweed and wildflowers, and possibly less moving."
Read the complete post here!
You may be hearing reports of another massive brood of cicadas emerging this year in Maryland, but UMD Entomologist Dr. Michael Raupp (a.k.a. "The Bug Guy") spoke with the Baltimore Sun recently to set the record straight. Unless you live in far Western Maryland, you'll enjoy another quiet spring and summer.
Read the complete article here!
RECENT DEPARTMENTAL NEWS
Entomology Graduate Students Nathalie Steinhauer and Meghan McConnell Collect Bees from California Almond Farm for USDA Testing – Los Angeles Times
Check out the full article here: goo.gl/6hSFZp
Entomology’s David O’Brochta Comments on the Testing of Genetically Modified Mosquitoes – NBC News
Check out the full article here: goo.gl/SnlvgQ