Dr. Leslie Pick has a new book out through Academic Press publishers titled Fly Models of Human Diseases. More information on her book can be found here. Check out the flyer below for more details!
We live in a world full of signals. We are constantly bombarded with exciting new combinations of light, sound, taste, smell, and texture. Ultimately our brains interpret these sensations to form what we call reality. However, as it turns out, human beings are only able to perceive a small slice of reality: there are many smells which, for better or worse, we can never smell, and we can only see a tiny slice of the colors light has to offer (we refer to this small portion of wavelengths as the “visible spectrum”).
As it turns out, flies do not base their behavior on the smell of the fruit: they base it on the smell of the yeast growing on the fruit. When yeasts are removed from fruit, the flies do not know where to go. Dr. Syed’s team took a sample of yeasts abundant in fruit and associated SWD flies and found that SWD choose certain yeasts over others, but why?
To answer this question, they sampled the odors that were produced by his yeasts using solid-phase microextraction (SPME) to see if they were different. They were in fact different – qualitatively and quantitatively - with each yeast isolate producing a very complex and wide range of odorant repertoire. Approaching the point of despair at interpreting all of his data, a statistician swooped in to save the day. The statistician was able to distinguish between the yeasts based solely on the odors they produce.
Read more about Dr. Syed’s Work
Scheidler, N. H., Liu, C., Hamby, K. A., Zalom, F. G., & Syed, Z. (2015). Volatile codes: Correlation of olfactory signals and reception in Drosophila-yeast chemical communication. Scientific reports, 5, 14059.
Hickner, P. V., Rivaldi, C. L., Johnson, C. M., Siddappaji, M., Raster, G. J., & Syed, Z. (2016). The making of a pest: Insights from the evolution of chemosensory receptor families in a pestiferous and invasive fly, Drosophila suzukii. BMC genomics, 17(1), 648.
About the author:
Brian Lovett is a PhD student in Dr. Raymond St. Leger’s Lab studying mycology and genetics in agricultural and vector biology systems. He is currently working on projects analyzing mycorrhizal interactions in agricultural systems, the transcriptomics of malaria vector mosquitoes, and the genomes of entomopathogenic fungi.
At the first Entomology colloquium of the Spring 2017 semester, Dr. Zain Sayed described his work on the agricultural pest spotted wing drosophila. His work unravels how female flies use odors from yeasts growing on fruit to find their mates.
Beginning in the Fall of 2016, the entire Department of Entomology pledged to become a green department . Partnering with the UMD Sustainability's Green Office Program we underwent an extensive audit, evaluation, and received a list of sustainable behaviors we are practicing well and where we have room for improvement.
We have 23 goals to meet, 11 of which we have achieved to become Bronze Certified. So, what actions have we taken so far? Check out our list of accomplishments below!
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.
The Greek philosopher Heraclitus was channeling his inner taxonomist when he declared, “everything is in flux.” Depending on who you ask, taxonomy as a field precariously teeters between being either the foundation of all other biological sciences or the most esoteric debate topic two scientists can choose. Scientists rely on taxonomists to draw the lines between the species that we study so we can all be on the same page while we study them (imagine trying to plan a trip to the zoo without names for the animals). As Dr. Jason Mottern explained during the last Entomology Department colloquium of 2016, these lines are often drawn in pencil.
Congratulations to the winners of the Spring 2017 Ernest N. Cory Undergraduate Scholarship!
Conservation biological control – a fancy term for the support of beneficial insects in a cropping system to enhance natural pest control - has long been of interest in organic agriculture. Lauren Hunt of the Department of Entomology’s Hooks Lab has been investigating the potential for conservation biological control in organic field corn using partridge pea (Chamaecrista fasciculata) to attract and support insects that feed on and parasitize pests. Many predators and parasitoids, collectively called beneficial insects or natural enemies, need nectar resources offered by flowers to successfully develop and reproduce. Partridge pea offers these nectar resources to insects in the form of flowers and via special glands, termed “extrafloral nectaries” located at the base of the petioles. These nectaries are particularly attractive to wasps known to parasitize a variety of insect pests, including stink bugs, corn earworms, and corn borers – common pests of corn and key pests in Lauren’s study.
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!
The kudzu bug (Megacopta cribraria) (Family Plataspidae) (Fig. 1) has become a widespread invasive pest in the southern United States since it was first detected in Georgia in 2009. This small, round bug is closely related to stinkbugs (Pentatomidae) and has plagued soybean farmers under non-treatment and high density conditions with yield losses as high as 59%! It feeds on the soybean plants’ leaves and stems with its piercing-sucking mouthparts, which can affect the number of seeds per pod and overall seed weight. The overall damage is astounding, especially when considering all kudzu bugs in North America originated from a single female bug from Japan. Luckily, many studies have been done to track and monitor this pest, such as those done by Jessica Grant.
It can be a lonely world for a bed bug researcher! Dr. Mark Feldlaufer began his presentation by extending an open invitation to visit his bed bug research lab at the United States Department of Agriculture-Agricultural Research Center in Beltsville, Maryland. He assured us that the offer rarely gets takers, and it is really not surprising, all things considered. As parasites that feed on people and cause itchy welts, bed bugs give people the heebie-jeebies. Just a picture or two of the bed bugs (Fig. 1) was enough to have several attendees visibly cringe, as they imagine the marks and persistent itches that usually follow after bed bug bites. However, Dr. Feldlaufer’s fascinating research, which aims to improve bed bug detection and control, may contribute to a future where everyone can rest assured that there truly are no creatures lurking under the bed.
often do not come in contact with them. It is impractical, dangerous, and against labelled usage, to coat every surface and crack of a home or business in insecticide, so bed bug chemical treatments often fail. The silver bullet control method appears to be heat treatments, but, like silver, heat treatments are expensive. Homes are heated to between 120-140⁰F for several hours to kill all bed bug life stages, which tend to cost anywhere between $2,500-$7,000. Though bed bugs themselves do not discriminate against the rich or poor, our methods of remediation tend to do just that. The most effective way to get rid of bed bugs is unaffordable to many.
In the course of his bed bug research, Dr. Feldlaufer has worked on other projects to help to detect and control bed bugs early in their infestations with a number of students, including our very own Dr. Kevin Ulrich. The team found that bed bugs consistently avoided a common chemical insect repellent, DEET, the main ingredient in most mosquito repellents. They did not, however, respond with greater avoidance to higher dosage. Although this may seem like a quick and easy fix, wearing DEET to bed may just cause bed bugs to merely move on to other surfaces (e.g. the couch). On the other hand, they also found that aldehyde compounds produced by bed bugs elicit a strong attractive response to other adult and immature bed bugs. These aldehydes may be one way bed bugs attract each other to form aggregations (Ulrich et al. 2016), suggesting that the aldehydes may be used to develop an inexpensive and more discreet option to lure and trap bed bugs. Dr. Feldlaufer currently aims to develop and test reduced risk pesticides that show promise in killing bed bugs.
Bed bugs can be a terribly menacing presence in anyone’s home, but thankfully Dr. Feldlaufer has dedicated much of his career to keeping us informed about these insects and their crafty activities. By pairing lures with reduced risk pesticides, Dr. Feldlaufer aims to develop options to safely, affordably, and discreetly ensure we can sleep tight assured that the bed bugs will not bite.
Lit L., Schweitzer J.B., and Oberbauer A.M. 2011. Handler beliefs affect scent detection dog outcomes. Animal Cognition 14: 387.
Pfiester M., Koehler P.G., and Pereira R.M. 2008. Ability of bed bug-detecting canines to locate live bed bugs and viable bed bug eggs. Journal of Economic Entomology 101(4):1389-96.
Ulrich, K.R., Kramer, M. and Feldlaufer, M.F. 2016. Ability of bed bug (Hemiptera: Cimicidae) defensive secretions (E)-2-hexenal and (E)-2-octenal to attract adults of the common bed bug Cimex lectularius. Physiological Entomology 41: 103-110.
Hanna Kahl is a master’s student at University of Maryland in Dr. Cerruti Hooks’ lab researching the effects of red clover living mulch on arthropod pests and pollinators.
Samuel Ramsey is a PhD student at University of Maryland in Dr. Dennis vanEngelsdorp’s lab researching Varroa destructor.
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.
Skunk, cilantro, burnt rubber—just a few of the many scents you might associate with the pungent odor produced by stink bugs. Like many animals, these bugs produce a variety of chemical odors (called semiochemicals) that modify the behavior of recipient organisms in different ways. That “stink” that these bugs get their name from is just one example. Stink bugs (family Pentatomidae) represent an extremely diverse family of insects that includes both agricultural pests and beneficial predators. Some of the agricultural pest species can cause millions of dollars in damages to crops. At the USDA Agricultural Research Service in Beltsville, Maryland, Dr. Don Weber studies stink bug semiochemicals in hopes of being able to take advantage of their communication to monitor their populations. In particular, Dr. Weber studies pheromones – one kind of semiochemical used for communication within a species. For example, male stink bugs emit pheromones to attract females, or in other cases, both females and males. In other insects, pheromones can also act to signal danger, food resources, or aggregation sites.
Because semiochemical signals often influence insect behavior, synthetically replicating these scents equips growers with a powerful tool to manage agricultural insect pests. This strategy works most effectively if the chemical composition of the natural odor is identified and isolated, and if the behavior it elicits is fully understood. The invasive brown marmorated stink bug (BMSB) (Halyomorpha halys) and the harlequin bug (Murgantia histrionica) (Figure 1) both respond to traps baited with pheromone lures which can be used in order to monitor levels of these pests to determine whether or not to take action against them with insecticides (Figure 2).
With stink bugs, there are some challenges that researchers such as Dr. Weber have faced in using pheromones as lures. Pheromones released by male stink bugs are not exclusively sex pheromones;females, males and nymphs alike are attracted by the male pheromones. This indicates to researchers that those pheromones might have some of the other roles mentioned above, such as signaling aggregation sites.
Yet another piece to this complicated smell puzzle stems from cross-species attraction, meaning that the deployment of a pheromone by one stink bug species can attract another stink bug species. Scientists can monitor BMSB by using MDT, the aggregation pheromone of a completely different stink bug species (the Asian brown-winged green bug, Plautia stali). However, because the pheromone is most attractive to BMSB in the fall, which is after most crop harvests have finished or already starting, so this is not very helpful for most growers1.
To produce better attractants for BMSB, researchers successfully identified the specific aggregation pheromone produced by BMSB adult males. The pheromone (commonly called murgantiol) is comprised of two different isomers, or molecular conformations, with a specific ratio. This ratio is important to know because there can be variation between species, and even between individual bugs, for what ratio is most attractive. Dr. Weber and colleagues determined which isomer ratio of murgantiol was most attractive separately to BMSB, and then combined this pheromone with MDT to see if a blend of the two was attractive to the bugs. The two pheromones together were much more attractive than either alone – with an added advantage of this blend being attractive to the bugs all season long, unlike MDT by itself. These pheromones also do not need to be extremely pure, which is good news for keeping the cost of lure production low.
Harlequin bug males produce murgantiol as well – so the same types of lures can be used to monitor both pest species, though the two species have different ideal isomer ratios5. Harlequin bugs, however, specialize in feeding on cruciferous plants – unlike BMSB, which are unspecific in their preferred hosts (polyphagous). Harlequin bugs were found by Dr. Weber to also be highly attracted to pheromones mixed with mustard oils, which are chemically derived from their host plants’ defensive compounds6,7. Adding these oils to murgantiol therefore could enhance trap performance for harlequin bugs, much like MDT for BMSB.
While Dr. Weber and his colleagues uncovered a lot of information about stink bug pheromones, there is still room to further our understanding. Now that researchers have evidence for which pheromone blends work most effectively for the two species, there is a lot of fine-tuning to be done about how exactly to use them in traps, and the most economical way to produce them. Dr. Weber and his colleagues also have plans in the works to investigate using pheromones for other pest-combating purposes, such as attracting insect predators of pest species like stink bugs, and genetically engineering plants to produce insect pheromones and act as trap crops. Overall pheromones offer an exciting approach to manage not only stink bugs, but many different pest insects, to better protect our agriculture.
To learn more about Dr. Weber’s research or contact him, visit his USDA homepage. For more information on BMSB or Harlequin bugs, you can visit the University of Maryland Extension pages on BMSB and Harlequin bugs.
Authors: Elizabeth Brandt, Aditi Dubey, Morgan Thompson
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
You have probably heard of at least one eight-legged femme fatale: the black widow. A female so fearsome she has inspired a multitude of book, movie and comic book characters. It turns out that this aggressive arachnid is not alone! Spiders are a group rich with outsized females. In biology, when one sex is differently sized than the other within the same species it is called sexual size dimorphism, or SSD. SSD can be male or female-biased, meaning either the male or female can be abnormally sized. Female-biased SSD, more common in egg-laying organisms, has evolved repeatedly in spiders. In fact, female-biased SSD has evolved four to nine times in the orb weaver group alone (Hormiga et al., 2000; Kuntner et al., 2015).
Dr. Matjaž Kuntner, the Chair of the Biological Institute at the Research Centre of the Slovenian Academy of Sciences and Arts, studies the phenomenon of female-biased SSD in orb weaver spiders and has made several fascinating discoveries. He first became interested in SSD during his graduate fieldwork in the tropics while earning his doctorate at George Washington University. While studying orb weaver systematics in places such as Southeast Asia, Madagascar and South Africa, he witnessed the obvious size discrepancies between males and females. He fell into the UMD web when he took Dr. Jeff Shultz’s course, Arthropod Form and Function, in our own Department of Entomology.
Both behaviors indicate that Nephilids exhibit something called sexual conflict. This is when males and females have opposing goals and strategies during mating and can lead to the sexes evolving ever more complicated ways to outsmart and outmaneuver one another (Kuntner et al., 2015). While Dr. Kuntner’s lab works primarily on Nephilid behavior, the Argiopines also exhibit sexual cannibalism and emasculation, indicating sexual conflict could play an important role in this group as well (Nessler et al., 2009).
One of Dr. Kuntner’s main goals is to understand the evolutionary patterns of female-biased SSD. In these systems, females are much larger than males, which begs the question: are females giants or are males dwarves? We assume that the ancestors of groups that exhibit SSD were once monomorphic, meaning males and females were the same size. Varying selection types and selection pressures lead to various iterations of SSD. Using analysis of evolutionary history, Dr. Kuntner was able to determine that the evolution of male and female body size is actually decoupled in Nephilids. Over time, females and males have both independently increased in size. However, females have undergone much greater increases over the same amount of evolutionary time. He termed this evolutionary pattern “sexually dimorphic gigantism.” Gigantism may evolve in Nephilid females in order to increase fecundity, or the number of eggs the female can carry (Lupše et al., 2016). In the Argiopines, while female and male size changes were positively correlated, there were no significant increases in body size. In fact, SSD appeared to decline over time.
Dr. Kuntner also wanted to know if the evolution of body size was directional. He tested three evolution models: Brownian motion, directional evolution, and single optimum. In Nephilids, he found that size evolution of females was not directional and fell under the“Brownian motion” model, meaning the changes in size over time were random. Nephilid male size evolution,
Additionally, Dr. Kuntner has done a lot of work on the different morphological and behavioral phenotypes that relate to SSD. He found that complexity in male and female genitalia coevolve (Kuntner, Coddington et al., 2009). Kuntner’s group determined that as female Nephilids evolve to increase fecundity by growing larger and developing ways to mate with multiple males, males respond by developing ways to prevent females from mating with other males. A male’s reproductive fitness increases when he prevents a female from mating with other males by ensuring that she only bears his offspring. One such strategy, called “plugging,” occurs when males essentially castrate themselves and plug the female genitalia to keep other males from being able to mate with her. Other strategies include “mate binding,” which is when a male spins a web around a female to keep her
Dr. Kuntner’s more recent work has shifted from studying the evolutionary arms race between male and female orb weavers to looking at the perils of gigantism in female orb weavers. How big is too big? How is mating still possible with females that are so much larger than males? To answer these questions, Kuntner and his team measured hundreds of spider bodies and spider private parts (Lupše et al., 2016). They determined that female body size (or somatic size) evolved independently from internal genital size. Similarly, male body size evolved independently from intromittent (sperm delivering) genital size. However, male intromittent genital size is correlated with female external genital size which indicates that the evolution of these reproductive organs in males helps prevent genital size mismatches that would be expected as a result of SSD (Fig. 3).
Dr. Kuntner plans to continue to explore the perils of gigantism in female orb weavers. There are many research questions that the mechanism of SSD poses, such as how gravity affects these large female spiders and how they have had to alter the web designs and functionality to compensate for increases in size.
About the Authors:
Grace Anderson is a Master’s student in the Shultz Lab at in the UMD Department of Entomology. Her work focuses on the evolution, behavior and systematics of harvestmen. She also is the Assistant Director of the Entomology Department’s Bug Camp.
Andrew Garavito is a Master’s student in Dennis vanEngelsdorp’s Lab. He is studying honey bees, with a focus on how pollen consumption impacts the ability of bees to fight off infections.
Cheng, R.C. & Kuntner, M. 2014. Phylogeny suggests non-directional and isometric evolution of sexual size dimorphism in argiopine spiders. Evolution. doi:10.1111/evo.12504
Hormiga, G., Scharff, N., & Coddington, J. A. (2000). The phylogenetic basis of sexual size dimorphism in orb-weaving spiders (Araneae, Orbiculariae). Systematic Biology, 49(3), 435-462.
Kuntner, M., Agnarsson, I. & Daiqin Li. 2015. The eunuch phenomenon: adaptive evolution of genital emasculation in sexually dimorphic spiders. Biological reviews 90: 279–296.
Kuntner, M., Arnedo, M.A., Trontelj, P., Lokovšek, T. & Agnarsson, I. 2013. A molecular phylogeny of nephilid spiders: Evolutionary history of a model lineage. Molecular Phylogenetics and Evolution 69: 961–979.
Kuntner, M. & Cheng, R.C. 2016. Evolutionary pathways maintaining extreme female-biased sexual size dimorphism: Convergent spider cases defy common patterns. In: Pontarotti, P. (ed) Evolutionary biology: Convergent evolution, evolution of complex traits, concepts and methods. Springer International Publishing, Cham, pp 121–133.
Kuntner, M., Coddington, J. A. & Schneider, J. M. 2009. Intersexual arms race? Genital coevolution in nephilid spiders (Araneae, Nephilidae). Evolution 63: 1451-1463.
Kuntner, M., Kralj-Fišer, S., Schneider, J. M. & Li, D. 2009. Mate plugging via genital mutilation in nephilid spiders: an evolutionary hypothesis. Journal of Zoology 277: 257-266.
Kuntner, M. & Elgar, M. A. 2014. Evolution and maintenance of sexual size dimorphism: Aligning phylogenetic and experimental evidence. Frontiers in Ecology and Evolution 2: 26.
Li, D., Oh, J., Kralj-Fišer, S. & Kuntner M. 2012. Remote copulation: male adaptation to female cannibalism. Biology letters 10.1098/rsbl.2011.1202
Lupše, N., Cheng, R.C. & Kuntner, M. 2016. Coevolution of female and male genital components to avoid genital size mismatches in sexually dimorphic spiders. BMC Evolutionary Biology 16:161
Nessler, S. H., Uhl, G., & Schneider, J. M. (2009). Sexual cannibalism facilitates genital damage in Argiope lobata (Araneae: Araneidae). Behavioral Ecology and Sociobiology, 63(3), 355-362.
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.
On Tuesday, October 18 UMD's Division of Research presented the winners of its 2nd Annual Research Communicator Impact Award at the 18th Annual Research Leader's Luncheon. The offering of this award began in 2015 with the intent of nominating researchers who take extra steps to share their research, opinions, and knowledge with the public though media means such as self-created videos, blogs, and news outlets.
The Department of Entomology's very own Dr. Mike Raupp was one of four recipients for the award. He won for his popular and engaging Bug of the Week blog and YouTube channel which engages the global community with the insect wonders found in Maryland.
More than 30 faculty members were nominated for the award across 12 different colleges and schools within the University.
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.
This past Saturday, members of the Department of Entomology heading on over to the College of Agriculture and Natural Resources (AGNR) Open House at the Central Maryland Research and Education Center in Ellicott City. The event lasted from 10 AM until 3 PM, where we engaged with many curious visitors, providing them with a wealth of information about our outstanding programs and the culmination of academic, research, and extension resources available to our students. In addition, guests got to participate in bird-watching, farm tours, interactive displays, and indulge in delicious treats from student organized food tents. Thank you to everyone who helped and attended! We hope to see you at UMD soon with all your FEARLESS IDEAS!
What makes a species a species? What are the characteristics that make it unique enough to be distinguished from similar creatures? What are the genetic underpinnings that allow species to evolve to create a distinct entity?
These are the type of questions Dr. Carlos Machado is trying to answer. Answering them are key to understanding our planet's biodiversity. A traditional definition of speciation centers around the concept of reproductive isolation. While members of two different species may mate, if they either produce no offspring or sterile offspring, these two individuals represent different species. This is known as the biological species concept. However, what factors lead to reproductive isolation? One way is through physical separation of populations (e.g., a mountain range) or allopatric speciation. On the other hand, what about sympatric speciation, or speciation in overlapping geographical distributions?
Dr. Machado’s work brings us a step closer to understanding the roots of speciation. Following from this work, his future research ideas center on correcting inversions using the latest genetic techniques, such as CRISPR (Clustered regularly interspaced short palindromic repeats), to study in further detail these regions that are responsible for species’ differences.
Jonathan Wang is a PhD student in Raymond St. Leger’s lab studying host-pathogen interactions.
Jen Jones is a PhD student in Bill Lamp’s lab, studying how socioeconomic factors influence the distribution of mosquito populations.
As the world’s population continues to grow, a key issue facing society is how to balance feeding the world while protecting the environment. Dr. Kate Tully has worked on this problem in both East Africa and the United States, where the solution will require different approaches, in part due to the different use of crops. In developed nations, many grain crops are grown for animal feed and fuel compared to developing nations where most are grown for human consumption. As such, different goals and approaches need to be taken for a sustainable future.
While crop yield has increased in many parts of world since the 1960s, this trend has not occurred in sub-Saharan Africa. Dr. Tully is working in Kenya and Tanzania to determine what changes can improve yield without excessive fertilizer use. Africa as a whole plans to increase nitrogen-based fertilizer use, but there is an upper limit to the amount plants can use before the rest is lost to the environment.
Large amounts of fertilizer nitrate were leached through the sandy soils to groundwater. Dr. Tully concluded that, in addition to using better overall management practices such as irrigation and increasing organic matter content, site characteristics should determine the optimal nitrogen fertilizer amount; in these cases, farmers in Kenya can increase yield by adding 75-100 kg N/ha while those in Tanzania should only use 50 kg N/ha. These levels can increase yield while protecting the environment from excess nitrogen leaching into waterways and gassing off into the air.
Back in the U.S., Dr. Tully turned her attention to soil nutrient dynamics on the Eastern Shore, Maryland. The dominant agricultural crops feed—corn and soybeans support their primary industry—poultry. Over the years, phosphorus from fertilizers and chicken litter has accumulated in the soil to the point of saturation. Phosphorus typically binds to soil particles with minimal nutrient leaching to the surrounding environment. Yet, as human-accelerated sea-level rise causes saltwater intrusion of coastal farmland, soil dynamics are changing. Saltwater can significantly alter soil chemistry, which may result in the release of bound soil nutrients as runoff. While nitrogen and phosphorus are essential nutrients for living organisms, too much can throw entire ecosystems off balance. Excess phosphorus in particular has led to algal blooms in fresh water estuaries. Over time algal blooms deplete life supporting oxygen resulting in ‘dead zones.’ But to what magnitude, rate, and extent are saltwater intrusions increasing the movement of phosphorus?
Read more of Dr. Tully’s work!
Tully K, Hickman J, McKenna M, Palm CA, Neill C. 2016. Effects of increased fertilizer application on inorganic soil N in East African maize systems: vertical distributions and temporal dynamics. Ecological Applications 26: 1907-1919. doi:10.1890/15-1518.1
Becca Eckert is a Ph.D. student in Bill Lamp’s lab. Her research examines how changes in light and nutrient availability affect macroinvertebrate growth and diversity in heterotrophic headwater streams as mediated by changes in leaf-associated algal quantity and quality.
Lisa Kuder is a Ph.D. student in Dennis vanEngelsdorp’s Bee Lab. Her research focuses on road ecology, specifically improving highway rights-of-way for pollinators.
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.
Dr. César Nufio has examined a vast number of grasshoppers to understand the impacts of climate change on insects in the Rocky Mountains of Colorado. To be precise, the number of specimens he has captured and processed over the last 10 years has exceeded 180,000 from grassland communities found along a high plains to subalpine gradient. Nufio’s National Science Foundation funded research combines extensive field surveys with comparisons of museum collections, weather data, and laboratory and field experiments. The entire project started with his discovery of a collection of 25,000 pinned and label grasshopper specimens and three data notebooks at the University of Colorado’s Natural History Museum. These pinned specimens and notebooks, which are part of the Gordon Alexander Collection, were part of several field studies conducted over 50 years ago.
In 2006, Nufio began resurveying the same sites that Alexander had nearly half a century ago. Nufio wanted to understand how climate had changed along the gradient and how this change might impact the timing of grasshopper life history events (when they hatched and how fast they developed), their elevational ranges and demography (population size, longevity, reproductive rates), and body sizes. All of these questions could be addressed comparing his recent findings to the observations made by Alexander.
In addition to examining phenology, Nufio more recently was interested in the demographic changes among species over the elevational gradient. He observed that species with short wings showed a reduction in body length with no change in reproductive output with increasing elevation. Conversely, grasshoppers with long wings showed no change in body size but a reduction in reproductive output. Nufio also examined changes in weight, longevity, and reproduction over time in response to temperature using a caged field experiment. During a warm year, he found that females tended to be heavier, live longer, and laid more eggs (more on demography: Article). While these subalpine grasshoppers appear to be benefiting from warming, his surveys suggest that those at the bottom of the mountain may be negatively affected by warm years.