In my current postdoctoral work at the University of Maryland (Department of Entomology; Dr. Bill Lamp’s lab) I’m interested in ecology and evolution of species interactions. Using arthropods and plant-insect study systems I’m curious what mechanisms (behavioral, molecular, physiological, etc.) drive species interactions, and especially interactions between native and introduced species.
I’m working on a variety of projects that involve primarily molecular biology techniques, microscopy, and morphometric analysis, but also field and greenhouse work. My primary projects include (a) using molecular biology tools to assess wetland-stream connectivity; (b) external morphology and host plant usage of the invasive spotted lanternfly using molecular approach, light microscopy and scanning electron microscopy; (c) plant DNA detection from gut contents of sap-feeders; (d) molecular identification of prey from predator diet; (e) plant resistance and tolerance to herbivores. A brief description for some of my projects is below. I will be adding more details as the projects grow.
I’ve been working on the spotted lanternfly (SLF) since April 2018. This emerging invasive insect pest is one of the most aggressive leaf-hopping pests in Mid-Atlantic region: it is extremely polyphagous and can utilize over 70 host plants, primarily trees. Since its introduction in Pennsylvania in 2014, the spotted lanternfly has rapidly spread in the eastern US, and it was finally detected in Maryland in October 2018. Nymphs and adults cause substantial plant damage by sucking phloem sap. Lanternfly nymphs switch host plants during their development; however, little is known about the relationship between the lanternfly and its tree hosts, as well as about the mechanisms of its unusual use of plant hosts during development (i.e. polyphagous behavior of early instars and nearly monophagous behavior of adults). We also don’t really know which plants the lanternfly utilize for feeding and which plants it uses for resting, migration, laying eggs, etc.
To address these issues in my research on the spotted lanternfly, I largely utilizes microscopy and molecular biology tools to (1) explore changes in external morphology of the lanternfly during its development, and (2) to confirm the utilization of host plants. Our two grant proposals on studying SLF external morphology and conducting molecular gut content analysis were funded by MDA and MAES in August 2018. Since then, I’ve been spending almost half of my time in the microscope room and the SEM laboratory. I’m curious to see how the lanternfy’s mouthparts and tarsi are so well adapted to feeding and moving on its host trees. Also, I’m applying our DNA barcoding protocol we’ve developed for another sap-feeder, the potato leafhopper, to confirm the lanternfly’s host plants. Almost two years later, since I started studying this species, I can’t stop being amazed by SLF unique ecology and behavior.
Utilization of molecular biology tools. To confirm host plant consumption and explore the potential host plant range of the lanternfly, I use molecular biology techniques to detect host plant DNA within the lanternfly gut contents. Plant DNA detection in insect gut contents has been one of the most accurate ways to confirm host plant utilization, however this method becomes challenging when dealing with sap-feeding insects: (a) the host plants are difficult to discern because piercing-sucking insects, such as the spotted lanternfly, often cause no direct symptoms to plants; (b) the lack of plant tissue in the gut of a piercing-sucking insect that feeds on phloem makes gut contents difficult to discern. Currently, I utilize Sanger sequencing to obtain a portion of plant chloroplast DNA region within the lanternfly gut contents. I successfully isolate and identify plant DNA for ‘single-DNA’-samples (i.e. when there is only one ingested host plant species in the lanternfly gut), and we are planning to use NGS technology to explore mixed DNA samples and compose a host plant range of the spotted lanternfly.
Scanning electron microscopy. To explore the morphological adaptations of the lanternfly to host plant utilization, I focus on the following two objectives: (a) to assess changes in morphology of the lanternfly mouthparts (stylets and labium), and (b) to assess changes in morphology of the lanternfly tarsal tips (arolia and tarsal claws) at each developmental stage. The labium, stylets, and tarsal tips are the structures which are associated with primary contact of the lanternfly with its host plant, and which potentially facilitate the lanternfly successful host plant use. I assess the developmental changes in these structures using both scanning electron microscopy (SEM) and morphometric analysis. We expect these structures to undergo substantial morphological and morphometric changes throughout the lanternfly development which could potentially indicates the lanternfly association with certain host trees at each developmental stage.
Update – 01/25/19: I’m presenting my intermediate results at the at the Entomological Society of America Annual Meeting, Eastern Branch, March 9-11,2019. Blacksburg, VA.
Update - 02/23/19: I’ve presented at the Annual Meeting of the Maryland Organic Food & Farming Association (Maryland Dept. of Agriculture, Annapolis, MD). My talk was on the lanternfly biology, behavior, and host plant usage.
Update - 02/28/19: I’ve finished the 2nd round of scanning electron microscopy of the lanternfly mouthparts and tarsi. Most of the beautiful SEM images are included in my poster for the upcoming EB-ESA meeting.
Update - 06/06/19: Our paper on external morphology of the spotted lanternfly has been submitted to PLOS ONE.
Update - 11/14/19: I’ve obtained all the sequences from the lanternfly gut content samples we used and finished data analysis. We’ve got some interesting results, and I’m currently working on getting the paper done (Tentative title: “Molecular gut content analysis reveals the host plant range of the invasive spotted lanternfly, Lycorma delicatula”). We are planning to submit it to Insects, the special issue on molecular gut content analysis of insect herbivores. Bill and I are co-editing this special issue and we hope to see many interesting studies there.
Update - 11/18/19: I’ve presented our updated results on the lanternfly external morphology at the ESA meeting. Here is my poster.
Plant DNA detection in insect gut contents is one of the most accurate ways to confirm host plant utilization, determine insect diet and interactions with other organisms. Most of the previous studies that involved molecular analysis of insect gut contents were primarily conducted on leaf-chewing insects, such as beetles, moths, or grasshoppers. Sap-feeders could be more challenging for molecular analysis of their gut contents because phloem sap presumably doesn’t contain plant DNA. However, this method was shown to be effective for potato psyllids (Cooper et al 2016) - apparently, while feeding an insect stylet (a piercing mouthpart) can consume not only phloem sap but can also pick up some of the surrounding plant cells which allows DNA to be detected in the insect gut contents. In this project, we would like to investigate whether (and how) we can apply this method for yet another sap-feeder, the potato leafhopper, to explore its host plant usage.
Update - 07/07/18: we are making some good progress, and we’ve submitted our oral presentation (A. Avanesyan and W. O. Lamp, “Use of molecular markers for plant DNA to determine host plant usage for potato leafhopper, Empoasca fabae”) also to the ESA meeting in Vancouver, BC, Canada.
Update – 11/15/18: presented!
Update - 06/10/19: the manuscript is in preparation.
Update - 09/10/19: the manuscript has been submitted to Environmental Entomology.
This is an ongoing project in Dr. Lamp’s lab. Using isopods from multiple wetland sites and streams in Maryland Delmarva Bays Wetlands we explore the potential connectivity between wetland and stream communities. Morphological identification of isopod species is tricky, and DNA barcoding, which I’m focusing on, is very helpful for estimating how ‘close’ wetland isopod species are to the isopod species inhabiting streams. I’m currently mentoring three students in this DNA barcoding work, and together with my mentees we isolate and sequence a portion of mitochondrial gene, cytochrome oxidase 1 (CO1), create a reference library of these sequences, and using a BLAST search engine in the NCBI GenBank database we assess species and genera identity of isopods.
Update - 02/22/19: Nina, my mentee, a high school student, who was working on this project since September 2018, presented her research project earlier this week at her school’s science fair and got 3rd prize! So exciting!
Update - 04/26/19: Nina presented her final poster at the ERHS Research Symposium.
Update - 06/06/19: We are currently exploring phylogenetic relationships between stream and wetland isopod species.
This is a new lab project I’m involved in and it is also a new challenge in my DNA barcoding work. I amplify DNA from dragonfly prey items. In addition to a gut content analysis, I’m working with degraded DNA from dragonfly feces. So far, I successfully amplified and sequenced COI partial gene from dragonfly feces produced during the first 2 hours post ingestion. The sequence analysis with subsequent BLAST results showed that the prey item was a crane fly. Surprisingly enough the DNA from the crane fly wasn’t degraded and an isolated fragment of 667 bp showed good sequence quality. These exciting results can make identification of dragonfly prey possible and accurately confirm (or even point to new) trophic interactions in dragonfly natural habitats.
Update - 06/10/19: DNA from mayfly was detected in feces produced during first 7 hours post ingestion by the same dragonfly individual. The sequence had lower quality but it was still readable.
This is a systematic review I was working on last year (manuscript submitted). The review aimed to identify patterns of grasshopper feeding preferences for native versus introduced plants and, consequently, grasshopper potential for biotic resistance of native communities, that (as the review has shown) is surprisingly overlooked in experimental studies on invasion ecology.
Update – 07/07/18: I’ve submitted a poster presentation on this review to the upcoming ESA meeting in Vancouver, BC, Canada. I’m also going to present it here, at the University of Maryland research symposium organized by the Office of Postdoctoral Affairs.
Update – 05/18/18: the manuscript has been submitted!
Although exotic chinese silver grass, a gorgeous ornamental plant and important biofuel source, can be highly invasive in some states, not all of its cultivars are invasive. I’ve been conducting field and greenhouse experiments to explore plant resistance and tolerance to grasshopper herbivory, how these responses differ among Miscanthus cultivars, and whether the initially introduced wild type demonstrates the highest level of herbivore resistance.
Update – 09/20/19: I’ve finished the analysis of the data we collected in 2018 and 2019 summer seasons; we see some interesting patterns in plant tolerance to herbivory and their association with plant morphological appearance; and I’m about to start working on the manuscript.
When I started working in Dr. Lamp’s lab I joined this ongoing project, and I spent some time ‘torturing’ herbarium plant specimens hoping that they will speak and tell me their taxonomic identity. I then analyzed plant diversity across several farms exploring whether and how plant diversity corresponds with the diversity of natural enemies, such as spiders.
Update - 12/17/18: I’m done with ‘torturing’ plant specimens. Plant diversity across different sites in Maryland has been analyzed, the plant data have been ‘matched’ to the spider diversity data, and my labmate, Dylan Kutz, will present the results at the Entomological Society of America Annual Meeting, Eastern Branch, March 9-11,2019. Blacksburg, VA.
Update - 05/24/19: Yet another two presentations with our updated results were submitted to the Annual meeting ‘Entomology-2019’.
In my postdoctoral work at the University of Wisconsin-Madison I studied one of the emerging insect pests – the spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae). This is a highly invasive insect species, which attacks undamaged ripening fruit of a wide variety of soft-skinned fruits and berries. Native to Southeast Asia, currently it is observed in Europe, North America, and South America. Drosophila suzukii has demonstrated a very high dispersal capacity and remarkable phenotypic plasticity – during only a couple of decades since its first introduction in Hawaii, D. suzukii invaded different temperate regions and now is being monitored in many northern and eastern states, as well as Canada.
I work on several projects on different aspects of D. suzukii biology and population distribution. I coordinated a multi-state bait comparison project for determining optimal attractants for D. suzukii. This project was conducted in Minnesota; we set up fly traps with eight different baits and conducted monitoring of D. suzukii in raspberry during several weeks. I also developed experimental design for the spatial and temporal distribution project which was supposed to be conducted later in the season when population of D. suzukii could be established.
I was also actively involved in a project on D. suzukii seasonal phenology focused on overwintering of D. suzukii and the effect of temperature and humidity on D. suzukii seasonal abundance. We are currently writing a paper on D. suzukii seasonal phenology which includes an analysis of the interactions between D. suzukii seasonal abundance and temperature and humidity dynamics during the collecting seasons in 2014-2015.
Additionally, I developed a protocol for tissue preparation, isolating spermathecae, and determining mating status of D. suzukii, which we have applied in our bait comparison and phenology studies. This protocol has been recently published in Insects (Special issue on invasive species). In this paper, we also demonstrated how this protocol can be applied for both field collected flies and flies reared in the lab, including fly specimens stored on a long-term basis.