Progress 01/01/09 to 12/31/13
Outputs
Target Audience: The target audiences for the biological and behavioral portions of this research were the housing industry, the public, and the pest management industry. Armed with more accurate biological and behavioral information, homeowners, apartment residents, housing managers and pest management professionals can make better informed, long-term decisions regarding bed bug prevention and management methods. The target audience for the bed bug resistance mechanism research, and the egg respirometry studies, is the scientific community. Identifying the genetic mechanisms responsible for bed bug resistance will help direct toxicologists and other researchers in thier development of more effective bed bug control measures. Likewise, the quantification of bed bug gas exchange and water loss through the egg shell will aid pesticide chemists in developing new formulations that might move through the bed bug operculum more effecively. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? I believe that all students benefit from working through a wide range of graduate experiences, which may include working on sponsored research projects that are very different from their own research, or evencollaboration withprofessors from other universities.All of the forementioned graduate students were provided with unique research opportunities both in the laboratory, and in the field. Andrea Polanco, learned many laboratory techniques while she was creating her bed bug lifetables. She experienced the joy offeeding bed bugs on chickens as well as making several collecting trips to highly infested apartments. Andrea also got totravel to the University of Kentucky to collect bed bugs with Dr. Alvaro Romero, who specializes in bed bug resistance.Matthew Reisconducted mostly laboratory studies on bed bug behavior, but I oftenrecruited Matthew to participate in field evaluations of bed bug products and other sponsored research. Matthew and Andrea also served as bed bug instructors for the Virginia Pest Management Association Master Technican programs that our laboratory puts on twice a year. Both Reina and Brittany have travelled to other laboratories to enhancethier professional development. Reina has travelled to the University of Minnesota to work with Dr. Stephen Kells on insecticide penetration of the bed bug cuticle.As mentioned previously, Brittany Delong has travelled to Auburn, AL to work with Dr. Art Appell. Both of these students are currently supervising sponsored bed bug research projects as well as conductng their own research. The above describes only how my graduate students have benefited from this project. However, it is important to notethat thousands of apartment managers, and pest management professionals in the nation and internationally have also received professional development training with regard to bedbug prevention and control due to this program.I have averaged >40 educational presentations per year over the last 5 years, andall have touched onvarious aspects of this research. How have the results been disseminated to communities of interest? The results of this project have been disseminated through referreed journal publications, extension fact sheets (13 produced in 2010-2011 in English and Spanish; number of downloads in 2012 was >1,083,000), presentations at scientific meetings and educational presentations. In 2011, our laboratorydelivered a total of 72 presentations at 56 venues resulting in 8639 face to face contacts. This average has remained consistant over the last three years. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
With regard toour first objective,"To develop bed bug life tables that list the expected development time, survivorship, and fecundity of laboratory and field collected bed bugs under conditions of differing temperature, relative humidity, feeding regimens and pesticide exposure stress", we completed these studies in 2011 and all were published (see list below) in referreed journals. In addition, the first author, Andrea Polanco,presented her work at 4 scientific meetings and gave numerous educationalpresentations to apartment renters (two presentations were made in Spanish),andpest managment professionals between 2010 and 2011. *Polanco, A.M., C.C. Brewster, and D.M. Miller. 2011. Population growth potential of the bed bug, Cimex lectularius L.: A life table analysis. Insects, 2: 173-185. doi: 10.3390/insects2020173. *Polanco, A.M., D.M. Miller, and C.C. Brewster. 2011. Reproductive potential of field-collected populations of Cimex lectularius L. and the cost of traumatic insemination. Insects, 2: 326-335. doi: 10.3390/insects2030326. *Polanco, A.M., and D.M. Miller, and C.C. Brewster. 2011. Survivorship during starvation for Cimex lectularius L. Insects, 2: 232-242. doi: 10.3390/insects2020232. Our second objective was "To determine the bed bugs' ability to emerge from an established harborage and locate a host held at different distances from that harborage, and determine if fed bed bugs will return to the established harborage or will relocate to a harborage closer to the host". This study was completed byMS student, Matthew Reise (see citation below).This study has resulted in one publication so far, but a second one has already been formatted. The information generated from this study was presented by Matthew at 3 scienifticmeetings, and Dr. Miller includes all of thehost seeking, and bed bug harborage information in herextension presentations (>40 presentationsin 2013). *Reis, M.D., and D.M. Miller. 2011. Host searching and aggregation activity of recently fed and unfed bed bugs (Cimex lectularius L.). Insects, 2: 186-194. doi: 10.3390/insects2020186. The data collection and analysis for thethird objective, "To use respirometry to determine the amount of water loss that a bed bug experiences after taking a blood meal, and to determine if bed bugs can modulate their CO2 release to reduce their moisture loss during periods of moisture stress", has been completed. Masters student, Brittany Delong, travelled three times to Auburn University in 2011 to work with Dr. Art Appell (a nationally recognized expert in insect respirometry). Brittany and Dr. Appell have quantified the the gas exchange rates of both susceptible and resistant bed bug eggs. They have also quantified water loss in three strains of eggs (2 resistant and 1 susceptible) and found no signifcant differences. This study is the first to quantify respiration and water loss in the bed bug egg stage. Manuscripts are being preparedfor journal submission. The fourth objective of this project was "To investigate the physiological mechanisms of bed bug insecticide resistance with the intention of identifying the genetic origins of these mechanisms." This objective bascially encompasses thedissertation research of my student, Reina Koganemaru.Reina has worked closely with Dr. Zach Adelman to learn molecular methods for identifying the genetic mecahnisms of resistance in insects, specifically bed bugs.So far,this research has resulted in two publications stating that bed bugs have not only kdr type resistance or enhanced mixed function oxidase activity but also reduced cuticular penetration. Reina is also currently working with Dr. Helms to extract proteins from thebed bug cuticle to confirm that the upregulated mRNA in the bed bug sequence data actually is manifested in an overabundance, or hypersclerotization of cuticular proteins in resistant bed bugs.In addition, Reina produced a summary article that describesall ofmethods used for bed bug control fromthe past and present. This publication is listed as in the "Top 12 most downloaded articles" for the Journal ofPesticide Biochemistry and Physiology (see below). *Koganemaru, R. ,D.M. Miller, and Z.N. Adelman. 2013. Robust cuticular penetration resistance in the common bed bug (Cimex lectularius L.) correlates with increased steady-state transcript levels of CPR-type cuticle protein genes. Pesticide Biochemistry and Physiology. 106: 190-197. *Koganemaru, R. and D.M. Miller. 2013. The bed bug problem: past, present and future control methods. Pesticide Biochemistry and Physiology. 106: 177-189. Adelman, Z.N., K.A., Kilcullen, R. *Koganemaru, M.A.E. Anderson, T.D. Anderson, and D.M. Miller. 2011. Deep sequencing of pyrethroid-resistant bed bugs reveal multiple mechanisms of resistance within a single population. PloS One. 6: e26228. doi:10.1371/jouirnal.pone0023228.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
*Koganemaru, R. and D.M. Miller. 2013. The bed bug problem: past, present and future control methods. Pesticide Biochemistry and Physiology. 106: 177-189.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
*Koganemaru, R.,D.M. Miller, and Z.N. Adelman. 2013. Robust cuticular penetration resistance in the common bed bug (Cimex lectularius L.) correlates with increased steady-state transcript levels of CPR-type cuticle protein genes. Pesticide Biochemistry and Physiology. 106: 190-197.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Z. N. Adelman, D. M. Miller, K. M. Myles. 2013. Bed Bugs and Infectious Disease: A Case for the Arboviruses. PLOS Pathogens.9:e1003462
|
Progress 10/01/12 to 09/30/13
Outputs
Target Audience: The target audiences for the biological and behavioral portions of this research were the housing industry, the public, and the pest management industry. Armed with more accurate biological and behavioral information, homeowners, apartment residents, housing managers, and pest management professionals can make better informed, long-term decisions regarding bed bug prevention and management methods. The target audience for the bed bug resistance mechanism research, and the egg respirometry studies, is the scientific community. Identifying the genetic mechanisms responsible for bed bug resistance will help direct toxicologists and other researchers in their development of more effective bed bug control measures. Likewise, the quantification of bed bug gas exchange and water loss through the egg shell will aid pesticide chemists in developing new formulations that might move through the bed bug operculum more effectively. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? I believe that all students benefit from working through a wide range of graduate experiences, which may include working on sponsored research projects that are very different from their own research, or even collaboration with professors from other universities. All of the aforementioned graduate students were provided with unique research opportunities both in the laboratory, and in the field. My student, Andrea Polanco, learned many laboratory techniques while she was creating her bed bug lifetables. She experienced the joy of feeding bed bugs on chickens as well as making several collecting trips to highly infested apartments. Andrea also got to travel to the University of Kentucky to collect bed bugs with Dr. Alvaro Romero, who specializes in bed bug resistance. Matthew Reis conducted mostly laboratory studies on bed bug behavior, but I recruited Matthew to participate in field evaluations of bed bug products and other sponsored research. Matthew and Andrea also served as bed bug instructors for the Virginia Pest Management Association Master Technican programs that our laboratory puts on twice a year. Both Reina and Brittany have travelled to other laboratories to enhance thier professional development. Reina has travelled to the University of Minnesota to work with Dr. Stephen Kells on insecticide penetration of the bed bug cuticle. As mentioned previously, Brittany Delong has travelled to Auburn, AL to work with Dr. Art Appell. Both of these students are currently supervising sponsored bed bug research projects as well as conductng their own research. The above describes only how my graduate students have benefited from this project. However, it is important to note that thousands of apartment managers, and pest management professionals in the nation and internationally have also received professional development training with regard to bed bug prevention and control due to this program. I have averaged >40 educational presentations per year over the last 5 years, and all have touched on various aspects of this research. How have the results been disseminated to communities of interest? The results of this projects have been disseminated through referred journal publications, extension fact sheets (13 produced in 2010-2011 in English and Spanish; number of downloads in 2012 was >1,083,000), and educational presentations at scientific meetings. In 2011, our laboratory delivered a total of 72 presentations at 56 venues resulting in 8639 face to face contacts. This average has remained consistant over the last three years. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
In 2013 we focused on the dataanalysis for the third objective, "To use respirometry to determine the amount of water loss that a bed bug experiences after taking a blood meal, and to determine if bed bugs can modulate their CO2 release to reduce their moisture loss during periods of moisture stress". MS student, Brittany Delong is first author on this study. Brittany has completed theanalysis and the final draft of thismanuscript. This study is the first to quantify respiration and water loss in the bed bug egg stage and will be submitted in April 2013. Brittany Delong is scheduled to graduate in the Spring of 2014. The fourth objective of this project was "To investigate the physiological mechanisms of bed bug insecticide resistance with the intention of identifying the genetic origins of these mechanisms." This objective bascially encompasses the dissertation research of my student, Reina Koganemaru. Reina has worked closely with Dr. Zach Adelman to learn molecular methods for identifying the genetic mecahnisms of resistance in insects, specifically bed bugs. So far, this research has resulted in two publications stating that bed bugs have not only kdr type resistance or enhanced mixed function oxidase activity, but also reduced cuticular penetration. Reina is also currently working with Dr. Helms to extract proteins from the bed bug cuticle to confirm that the up regulated mRNA in the bed bug sequence data, actually is manifested in an over abundance, or hypersclerotization of cuticular proteins in resistant bed bugs. In addition, Reina produced a summary article that describes all of methods used for bed bug control from the past and present. This publication is listed as in the "Top 12 most downloaded articles" for the Journal of Pesticide Biochemistry and Physiology in 2013.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
*Koganemaru, R. and D.M. Miller. 2013. The bed bug problem: past, present and future control methods. Pesticide
Biochemistry and Physiology. 106: 177-189.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
*Koganemaru, R.,D.M. Miller, and Z.N. Adelman. 2013. Robust cuticular penetration resistance in the common bed bug
(Cimex lectularius L.) correlates with increased steady-state transcript levels of CPR-type cuticle protein genes. Pesticide
Biochemistry and Physiology. 106: 190-197.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Z. N. Adelman, D. M. Miller, K. M. Myles. 2013. Bed Bugs and Infectious Disease: A Case for the Arboviruses. PLOS
Pathogens.9:e1003462
|
Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: This project (A Survey of Bed Bug (Cimex lectularius L.) Ecology: Fecundity and Survivorship, Host Location and Mechanisms of Resistance) was designed to improve our understanding of the mechanisms that allow the common bed bug to survive and proliferate within the human environment. As of 2011, we had investigated how bed bugs withstand long periods of starvation, how they locate hosts over distance, and described the genetic and physiological mechanisms that allowed them to survive exposure to pesticide residues. Another paper describing a third mechanism of resistance (reduced cuticular penetration) was submitted this past month (Oct. 2012). These studies fulfulled Objectives 1, 2, and 4 of this proposal. In May 2012, we began working on Objective 3. For this objective, respirometry was going to be used to determine if resistant strain bed bugs could modulate their respiration (and thus reduce repiratory water loss) more effectively than susceptible bed bugs. This study is being focused on the bed bug egg stage specifically. Eggs are more difficult to kill with insecticides than either the nymph or the adult life stages. Our preliminary studies have also indicated that resistant strain eggs are more difficult to kill than susceptible eggs. Our laboratory has been cooperating with Dr. Arthur Appel at Auburn University to measure the rate of bed bug embryo respiration through the operculum. Dr. Appel is the national expert on insect respirometry and his methods have set the standard within the scientific community. Our goal is to measure the rate of oxygen consumption and carbon dioxide production in susceptible and resistant bed bug eggs at different temperatures. We will then compare their respiratory quotients (RQ values). We will also be quantifying differences in water loss between the two strains. We hypothesize that if resistant bed bugs can limit the amount of water moving out of the operculum, they may also be able to limit the amount of water-based insecticide moving in. Thus far, the RQ values have been quantified for the susceptible strain eggs at temperatures ranging from 20-35 degrees C. For the resistant strain, only the RQ value at 25 degrees C has been calculated. This value was not significantly different from that calculated for the susceptible strain at the same temperature. Some of the preliminary respirometry and water loss data have already been presented at the 2012 Entomological Society of America Meeting in Knoxville, TN. PARTICIPANTS: To date, I have had four graduate students involved in the completion of this project. Both Andrea Polanco (MS 2011)and Matthew Reis (MS 2010) were responsible for completing Objectives 1 and 2 (respectively) as part of their thesis reserach. Reina Koganemaru (Ph.D in progress), has been responsible for completing Objective 4. Reina has been able to identify three bed bug resistance mechanisms in a single (local) bed bug strain. Her resistance work has resulted in several collaborations: Dr. Stephen Kells, Associate Professor of Entomology at USM; Dr. Zach Adelman, Associate Professor of Entomology at Virginia Tech; and Dr. Troy Anderson, Assistant Professor of Entomology at Virginia Tech. Reina has received speciailzed training from each of her collaborators. Reina had no experience with molecular techniques upon arriving to Virginia Tech. In working with Zach Adelman she has learned, and published, on how to use deep sequencing to identify the upregulation of genes that code for detoxification enzymes and cuticular proteins. From Dr. Anderson she has learned how to formulate, topically apply, and inject bed bugs with doses of insecticide to quantify bed bug resistance levels. In working with Dr. Kells, Reina has also learned how to dissect bed bugs, removing their viscera without disturbing the cuticular hydrocarbons on their exocuticle. This careful removal of the viscera was done so that both the internal and external components of the bed bug could be extracted for GC-MS analysis. Reina then analyzed these components using GC-MS to quantify the amount of insecticide residues that have penetrated the cuticle over time. Brittany Delong is a new MS student who is currently characterizing the bed bug egg. Her research has attempted to find unique characteristics in the operculum of resistant bed bugs eggs that might contribute to their reduced susceptibility to insecticides. As noted in the first section of this report, Brittany has been learning how to use respirometry to quantify the respiration rate and subsequent water loss in bed bug eggs. She is collaborating with Dr. Arthur Appel of Auburn Unversity to complete Objecive 3 of this research project. TARGET AUDIENCES: The target audiences for the biological and behavioral portions of this research were the housing industry and the pest management industry. Armed with more accurate biological and behavioral information both the pest management and housing industry can make better informed, long-term decisions regarding bed bug management techniques. The target audience for the bed bug resistance mechanism research is the scientific community. Identifying the genetic mechanisms responsible for bed bug resistance will help direct toxicologists and other researchers in their development of more effective bed bug control measures. Likewise, our attention to the respiration of the (impenetrable) bed bug egg, will aid pesticide chemists in developing new formulations that might move through the bed bug operculum more effectively. PROJECT MODIFICATIONS: Instead of quantifying the respiration and water loss of bed bug adults and nymphs (Objective 3), we will be quantifying respiration of the bed bug egg only. Dr. Appel at Auburn University is already working on respiration in the mobile bed bug life stages. My student's thesis research was focusing on eggs, therefore, it made sense for us to continue with eggs only.
Impacts
The mechanisms of resistance identified in our Objective 4, specifically the reduced cuticular penetration mechanism, have been presented at several scientific meetings, including the Entomological Society of America in 2011 and 2012; the 2012 National Conference on Urban Entomology (NCUE); the 2012 Virginia State Technical meeting; and the 244th American Chemical Society National Meeting and Exposition (2012). The presentation of these resistance mechanisms has resulted in our collaboration with two molecular/toxicological researchers at Virginia Tech (Zach Adleman- 2 papers; one published in 2011 and one submitted in 2012; and Troy Anderson- one paper in preparation in 2012). This year, we also began a collaboration with Dr. Stephen Kells at the University of Minnesota. My Ph.D. student, Reina Koganemaru was invited by Dr. Kells to USM and learn gas chromatography and mass spectrophotometry (GC-MS) in his laboratory. This collaborative project is intended to specifically quantify insecticide penetration through the bed bug cuticle (compared with how much insecticide simply stays on the outside of the body). We will then compare the amount of penetration between resistant and susceptible strains. This collaboration is on-going and the data will continue to be collected through the spring of 2013. The impact of these collaborations will be a better understanding of the bed bug cuticle and other resistance mechanisms. This improved understanding of resistance mechanisms will ultimately help guide us in the search for more effective bed bug control measures.
Publications
- No publications reported this period
|
Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: As of May 2011, we have completed Objectives 1, 2, and 4 of this research project. The first objective involved the creation of stage dependent life tables for the common bed bug. These life tables have now been published, thus making the potential fecundity, development time, and survivorship of both susceptible and resistant bed bugs available to other researchers. Similarly, our second objective (evaluating bed bug host searching time) was also published this year. Specifically, we found that bed bugs that were stimulated to feed and fed successfully, returned to the harborage very rapidly (within 30 min) and remained there for the duration of the scotophase. However, bed bugs that were stimulated to feed but were not able to obtain a blood meal, continued to search for the host all night until two hours prior to the onset of the scotophase, when all insects returned to the harborage. Our fourth objective investigated the physiological mechanisms of bed bug resistance to pyrethroid insecticides. Our study revealed that multiple mechanisms could be present in a single bed bug strain. The first and most common resistance mechanism was the kdr-type resistance (L9251 mutation on the alpha subunit of the sodium channel receptor). However, deep-sequencing of the adult bed bug transcriptome also revealed several overexpressed cytochrome P450 and carboxylesterase genes in the resistant strain bed bugs. These results indicated that the resistant bed bug strain also had enhanced detoxification enzyme activity contributing to their overall resistance levels. The results of this study were also published this year. The results of the first two objectives were presented in 2011 at the US EPA Bed Bug Summit in Washington, D.C.; the North American Bed Bug Summit in Chicago IL; the National Pest Management Association Meeting, in New Orleans, LA; and numerous regional pest management meeting across the country. The results of the bed bug resistance mechanisms study were presented at the 2011 Entomological Society of America Meeting in Reno, NV. PARTICIPANTS: Andrea Polanco was a Master's student in the Department of Entomology. Objective 1 was part of her thesis research. Andrea graduated in the Spring of 2011. Matthew Reis was a Master's student in the Department of Entomology. Objective 2 was part of his thesis research. Matthew graduated in the Fall of 2010. Reina Koganemaru is currently a Ph.D. candidate in the Department of Entomology. Certain elements of Objective 4 were part of her dissertation research. TARGET AUDIENCES: The target audiences for the biological and behavioral research were the scientific community, the housing industry, and the pest management industry. Armed with more accurate biological and behavioral information, both the housing and pest management industries can make better, long-term decisions regarding bed bug management techniques. The target audience for the bed bug resistance mechanisms research was the scientific community. Knowing the genetic mechanisms responsible for bed bug resistance will help to direct toxicologists and other researchers in their development of more effective bed bug control measures. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Experimental life tables were constructed and analyzed for three strains of the common bed bug: a pyrethroid-susceptible laboratory strain (HS), a highly resistant field strain (RR), and a field strain with a declining level of resistance (KR). Egg to adult survival in the RR strain was 94% compared with 79% and 69% in the HS and KR strains, respectively. The RR strain also developed significantly faster from egg to adult (~35 days) than the other two strains (~40 days). The average life expectancy for a newly laid egg was ~143 days, and that of a newly molted adult was ~127 days. Females produced an average of 0.64 daughter eggs/day with the highest weekly production during the fifth week of adult life. The net reproductive rate of the RR strain indicated a 35-fold increase in the population per generation (~92 days). The intrinsic rate of increase indicated that the population multiplies 1.1 times/female/day (λ) and doubles in size every 13 days. The results of this study are the first to be published, and they allow us to predict how fast a bed bug infestation can potentially grow in a stable environment (home or apartment). A subsequent and supplementary study quantifying how long bed bugs of different life stages could live without a blood meal, allowed us to predict how long bed bugs could live inside an apartment with no host present (vacant). Overall, fifth instar and adult bed bugs could live an average of 70 days without a blood meal. However, first instars were more susceptbile to dehydration and could only live an average of 20 days. Our study regarding the mechanisms of bed bug resistance to pyrethroids was the first to record multiple resistance mechanisms within the same population. Our results have indicated that certain bed bugs populations not only can have kdr-type resistance but also enhanced detoxification enzyme activity. Subsequent studies have also revealed the potential for a third type of resistance within the same population, specifically, reduced cuticular penetration. Our understanding of these mechanisms will help guide us in the search for new, more effective, insecticide formatulation for bed bug control.
Publications
- Reis, M.D., and D.M. Miller. 2011. Host searching and aggregation activity of recently fed and unfed bed bugs (Cimex lectularius L.). Insects, 2: 186-194. doi: 10.3390/insects2020186.
- Adelman, Z.N., K.A., Kilcullen, R. Koganemaru, M.A.E. Anderson, T.D. Anderson, and D.M. Miller. 2011. Deep sequencing of pyrethroid-resistant bed bugs reveal multpile mechanisms of resistance within a single population. PloS One. 6: e26228. doi:10.1371/jouirnal.pone0023228.
- Polanco, A.M., C.C. Brewster, and D.M. Miller. 2011. Population growth potential of the bed bug, Cimex lectularius L.: A life table analysis. Insects, 2: 173-185. doi: 10.3390/insects2020173.
- Polanco, A.M., D.M. Miller, and C.C. Brewster. 2011. Reproductive potential of field-collected populations of Cimex lectularius L. and the cost of traumatic insemination. Insects, 2: 326-335. doi: 10.3390/insects2030326.
- Polanco, A.M., D.M. Miller, and C.C. Brewster. 2011. Survivorship during starvation for Cimex lectularius L. Insects, 2: 232-242. doi: 10.3390/insects2020232.
|
Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: As of 2010, we have completed the first and second objectives of this project. The first objective involved the creation of the stage dependent life tables for the common bed bug, Cimex lectularius. To develop these lifetables (both resistant and susceptible to insecticides) bed bugs eggs were reared through adulthood, and through production of the F1 generation so that we could quantify fecundity, survivorship, and time to development within each strain. Our second objective evaluated bed bug activity after feeding (during the scotophase). Multiple laboratory assays were conducted to observe the behavior of single sex adults (groups of 10) after successfully or unsuccessfully taking a blood meal during the scotophase. As part of the second objective we also quantified bed bug movement patterns when attempting to locate a host from different distances. Laboratory bioassays were conducted to evaluate the time, distance, and straightness of path taken by bed bugs located at different distances from a host. Antennectomized bed bugs were also assayed to determine their host location ability. The fourth objective investigated the physiological mechanisms of bed bug insecticide resistance using transcriptome analysis. We have made significant progress on this objective. PARTICIPANTS: Andrea Polanco, MS student: Andrea was responsible for the generation of all bed bug life table data. Matthew Reis, MS student: Matthew was responsible for the collection of all host detection and behavioral data. Reina Koganemaru, Ph.D. student: Reina is conducting all of the reistance bioassays and generating molecular data. Zach Adelman, Assistant Professor, Virginia Tech: Dr. Adelman is the molecular biologist responsible for conducting the bed bug transcriptome analysis. Carlyle Brewster, Associate Professor, Virginia Tech: Dr. Brewster is the population dynamics specialist and was responsible for overseeing the development of the bed bug life tables and population projection models. TARGET AUDIENCES: Because bed bug infestations have reached epidemic levels, our target audiences include the general public, research scientists, the housing industry, hospitality industry, and HUD, the Environmental Protection Agency, and the pest management industry. All of the research results generated by this project are aimed at increasing the knowledge of these audiences so that they may better defend themselves against bed bugs. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We found differences in the biological characteristics of bed bug strains, susceptible and resistant to insecticides. The average number of eggs produced by a single susceptible female after taking a blood meal was 21.6. The mean number produced by a resistant female was 11.7. The average time for a susceptible bed bug egg to develop into a reproductive adult was significantly longer (43.0 d) than that of a resistant bed bug egg (37.0 d). Susceptible adult bed bugs also lived significantly longer (96 d) than resistant bed bugs (43.3 d) during starvation. These results suggest that resistant strain bed bugs have a lower overall fitness than the susceptible strain bed bugs. We compared nocturnal activity for bed bugs that were successful or unsuccessful at taking a blood meal. Bed bugs that fed successfully returned to the harborage almost immediately (within one half hour) after feeding. Bed bugs that were unsuccessful continued to forage throughout the night not returning to the harborage until two hours prior to the photophase. In host location assays, bed bugs placed far away from the host traveled greater distances and took more circuitous route than those located at shorter distances. Bed bugs that were antennectomized located the host (25 cm away) within 126 seconds. With regard to our evaluation of resistance mechanisms, we initiated preliminary sequencing of the bed bug transcriptome using the Roche 454 platform. We generated more than one million reads each for the susceptible and resistant strains. These reads were assembled together into more than 10,000 large contigs. Assembled contigs were converted into a BLAST database and queried with P450, carboxylesterase (CE) and GST protein sequences from a selection of the currently sequenced insect genomes. Matching contigs were queried back against the raw reads and extended where possible. The number of raw reads mapping to each identified GST (12 contigs), P450 (27 contigs) and CE (17 contigs) for each strain was plotted along with data from 1000 randomly selected contigs. While most GST, P450 and CE contigs follow a regression line fairly well, reads mapping to two GST contigs and one P450 contig were extremely overrepresented in the resistant strain. Phylogenetic analysis of the C. lectularius GST family revealed that the two overrepresented contigs were members of the delta and sigma classes. While delta-class GSTs have been associated with insecticide resistance previously this is the first instance we are aware of where a sigma-class GST is potentially associated with resistance. We observed differences in resistance ratios when the resistant strain bed bugs were challenged topically versus via injection into the thoracic cavity. We reasoned that changes in the cuticle may have occurred in this strain. Using transcriptome data, we were able to identify 13 transcripts which encoded for the R&R chitin-binding domain found in cuticle protein sequences. Four of these transcripts appeared to be up-regulated in the resistant strain. Two of the transcripts are predicted to encode for RR1 type proteins (soft cuticle), while the other two are predicted to encode for RR2 (hard cuticle).
Publications
- No publications reported this period
|
Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Activities: In 2009, we began the bed bug life-table studies. Virgin bed bugs were placed together in couples and fed weekly so that egg production could be recorded each day until the onset of adult mortality. In an additional experiment, the first day F1 generation of eggs produced by the virgin males and females were separated into cohorts at the egg stage. The nymphal development time and survivorship for each life stage were recorded until adulthood. All of these experiments were used to determine adult survivorship, adult fecundity, nymphal development time and survivorship at each developmental stage under laboratory conditions. Dissemination: My students and I have all been very active in disseminating our bed bug research. As of November 16th, 2009, members of our laboratory have made over 20 international, national, regional, and state presentations to stakeholders on bed bug biology (development, survivorship, and fecundity) and control. Our stakeholders include the pest control industry, our new IPM partners in the government housing authorities and apartment associations, the regional health departments, state regulators, the general public, and academics. Overall, we have disseminated our bed bug research results to over 2750 (face-to-face) contacts this year. PARTICIPANTS: To date, the majority of our research has been conducted by a master's student, Andrea Polanco under the supervision of Dr. Dini Miller. Andrea Polanco will be completing her MS degree in the Fall of 2010 and transferring to a Ph.D. program at the University of Florida. Dr. Dini Miller is the Urban Pest Management Specialist for the state of Virginia and has been working on bed bug biology, behavior, and control since 2005. TARGET AUDIENCES: Because bed bug infestations have reached epidemic levels, our target audiences include the general public, research scientists, the housing industry, hospitality industry, and HUD, the Environmental Protection Agency, and the pest management industry. All of the research results generated by this project are aimed at increasing the knowledge of these audiences so that they may better defend themselves against bed bugs. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The results of our bed bug biology studies have determined that the existing literature (dated mostly from the 1930s in the United Kingdom) is not accurate for the populations currently infesting the United States. For example, Johnson (1938) stated that adult bed bugs could live for 1.5 years without feeding. Our studies indicate that pyrethroid resistant field strain bed bugs cannot live more than 69 days without feeding. Our studies also suggest that there may be a trade-off in pyrethorid resistance and bed bug fecundity/survival. For example, laboratory strain bed bugs produce a mean of 18 eggs per blood meal (SE 2.2). The field strain produces significantly fewer eggs (11.5 plus; SE 0.9) per blood meal. Also, the field strain bed bugs do not produce as many eggs in their lifetime as Johnson (1938) predicted (500 eggs). Our field strain females produced approximately 83 eggs each (range 62.01-83.05) prior to mortality. Half of these test females (fed every 7 days) were dead 4 months after egg production began. However, each female did produce 5 batches of eggs (each egg laying period lasting 8-14 days) during her relatively short lifespan. These studies have been used to teach researchers, pest control operators and the public that they cannot rely on the old bed bug literature to describe the new pyrethroid resistant populations in the United States. Prior to the presentation of this research, all of the bed bug researchers and pest control operators had been quoting Johnson (1938) or Usinger (1966; who quotes Johnson 1938) because there were no other sources of bed bug information. Therefore, our outcomes, as of this year, have increased the bed bug knowledge of researchers, pest control operators, public health practitioners, and housing authorities. We expect that this research will later be used by pest control operators, housing authorities and hotel managers to set more realistic "times to occupancy" after an infestation has been treated.
Publications
- No publications reported this period
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