Talbot, B., M. Vonhof, H. G. Broders, M. B. Fenton, and N. Keyghobadi. 2017. Population structure in two geographically sympatric and congeneric ectoparasites: Cimex adjunctus and Cimex lectularius, in the North American Great Lakes region. Canadian Journal of Zoology. doi: 10.1139/cjz-2017-0014
“Subdivided populations can be described by different models of population structure that reflect population organisation, dynamics and connectivity. We used genetic data to investigate population structure in two geographically sympatric, congeneric species of generalist ectoparasites of warm-blooded animals. We characterized the spatial genetic structure of Cimex adjunctus Barber, 1939, an understudied and fairly abundant species, using microsatellite markers at a spatial scale representing contemporary dispersal of the species. We found seven genetic clusters, global G’ST of 0.2, 33% of genetic variation among sites, and non-significant isolation-by-distance. We compared these results with Cimex lectularius L., 1758, a closely related but conversely well-known species, in the same geographic area. We found stronger genetic structuring in C. lectularius than in C. adjunctus, with eleven genetic clusters, G’ST of 0.7, 57% of genetic variation and significant but weak isolation-by-distance (R2 = 0.09). These results suggest that while both species can be described as having classic metapopulation structure, C. adjunctus leans more towards a patchy population and C. lectularius leans more towards a non-equilibrium metapopulation. The difference in population structure between these species may be attributable to differences in movement potential and extinction-colonization dynamics.”
Narain, R. B., S. Lalithambika, and S. T. Kamble. 2015. Genetic variability and geographic diversity of the common bed bug (Hemiptera: Cimicidae) populations from the Midwest using microsatellite markers. Journal of Medical Entomology. 52: 566–572. doi: 10.1093/jme/tjv061
“With the recent global resurgence of the bed bugs (Cimex lectularius L.), there is a need to better understand its biology, ecology, and ability to establish populations. Bed bugs are domestic pests that feed mainly on mammalian blood. Although bed bugs have not been implicated as vectors of pathogens, their biting activity inflicts severe insomnia and allergic reactions. Moreover, they have recently developed resistance to various insecticides, which requires further molecular research to determine genetic variation and appropriate interventions. Population dynamics, including genetic differentiation and genetic distance of 10 populations from the Midwest were analyzed in this study. The bed bug samples collected by pest control companies were genotyped using eight species-specific microsatellite markers. Results showed all eight markers were polymorphic, with 8-16 alleles per locus, suggesting high genetic diversity. The FST values were >0.25, signifying pronounced genetic differentiation. The G-test results also indicated high genetic differentiation among populations. The frequency of the most common allele across all eight loci was 0.42. The coefficient of relatedness between each of the populations was >0.5, indicative of sibling or parent-offspring relationships, while the FIS and its confidence interval values were statistically insignificant within the populations tested. The populations departed from Hardy-Weinberg equilibrium, possibly because of high heterozygosity. The genetic distance analysis using a neighbor-joining tree showed that the populations from Kansas City, MO, were genetically separate from most of those from Nebraska, indicating a geographic pattern of genetic structure. Our study demonstrated the effectiveness of using microsatellite markers to study bed bugs population structure, thereby improving our understanding of bed bug population dynamics in the Midwest. Overall, this study showed a high genetic diversity and identified several new alleles in the bed bug populations in the Midwest.”
Fountain, T., L. Duvaux, G. Horsburgh, K. Reinhardt, and R. K. Butlin. 2014. Human-facilitated metapopulation dynamics in an emerging pest species, Cimex lectularius. Molecular Ecology. 23: 1071–1084. doi: 10.1111/mec.12673
“The number and demographic history of colonists can have dramatic consequences for the way in which genetic diversity is distributed and maintained in a metapopulation. The bed bug (Cimex lectularius) is a re-emerging pest species whose close association with humans has led to frequent local extinction and colonization, that is, to metapopulation dynamics. Pest control limits the lifespan of subpopulations, causing frequent local extinctions, and human-facilitated dispersal allows the colonization of empty patches. Founder events often result in drastic reductions in diversity and an increased influence of genetic drift. Coupled with restricted migration, this can lead to rapid population differentiation. We therefore predicted strong population structuring. Here, using 21 newly characterized microsatellite markers and approximate Bayesian computation (ABC), we investigate simplified versions of two classical models of metapopulation dynamics, in a coalescent framework, to estimate the number and genetic composition of founders in the common bed bug. We found very limited diversity within infestations but high degrees of structuring across the city of London, with extreme levels of genetic differentiation between infestations (FST = 0.59). ABC results suggest a common origin of all founders of a given subpopulation and that the numbers of colonists were low, implying that even a single mated female is enough to found a new infestation successfully. These patterns of colonization are close to the predictions of the propagule pool model, where all founders originate from the same parental infestation. These results show that aspects of metapopulation dynamics can be captured in simple models and provide insights that are valuable for the future targeted control of bed bug infestations.”
Potter, M. F., and K. F. Haynes. 2014. Bed bug nation: is the United States making any progress? Proceedings of the 8th International Conference on Urban Pests, 20-23 July 2014, Zurich, Switzerland. 51–58.
“Contrary to recent news reports, the United States continues to be inundated with bed bugs (Cimex lectularius L.). Based on a nationwide survey of pest professionals, infestations still are increasing. While most pervasive in residences, the bugs are becoming more common in schools, offices, public transportation and other locales where beds are not normally present, paralleling historical trends for this insect. Bed bugs continue to be the most challenging pest encountered by professionals. The cost of extermination is exceeding the budgets of many households and businesses, the majority of whom are averse to spending more on pro-active inspections and other preventative measures. Pest managers in the U.S. are becoming more experienced with bed bugs, and have better tools for providing relief to those who can afford their services. Prospects are less hopeful for the poor, and widespread resistance to insecticides is a global predicament. Absent of a coordinated societal response with affordable science-based pest management tactics, prospects for curtailing the resurgence appear unlikely.”
Pereira, R. M., A. S. Taylor, M. P. Lehnert, and P. G. Koehler. 2013. Potential population growth and harmful effects on humans from bed bug populations exposed to different feeding regimes. Medical and Veterinary Entomology. 27: 148–155. doi: 10.1111/j.1365-2915.2012.01057.x.
“Effects of host availability and feeding period on bed bugs, Cimex lectularius (L.) (Hemiptera: Cimicidae), were measured. Population growth and the potential harmful effect of bed bug populations on human hosts were modelled. Bloodmeal sizes were affected by both feeding length and frequency, with >2-fold difference between insects fed daily or weekly. Blood consumption increased >2-fold between bed bugs fed occasionally and often, and 1.5-fold between occasional and daily feeding. Bed bugs fed more often than once a week, potentially every 2-4 days. Egg production was associated with nutrition, being strongly correlated with blood consumption in the previous week. Bed bug populations can grow under different feeding regimes and are hard to control with <80% mortality. Bed bugs can survive and grow even in locations with a limited blood supply, where bed bug persistence may be important for the continual spread of populations. Persistence in non-traditional locations and a potential association with human pathogens increase the health risks of bed bugs. Potential blood loss as a result of a bed bug can have serious consequences because uncontrolled populations can reach harmful levels in 3-8 months. The reproduction potential of bed bug populations suggests serious consequences to human health and the need for efficacious control measures.”
Booth, W., V. L. Saenz, R. G. Santangelo, C. Wang, C. Schal, and E. L. Vargo. 2012. Molecular markers reveal infestation dynamics of the bed bug (Hemiptera: Cimicidae) within apartment buildings. Journal of Medical Entomology. 49: 535–546. doi: 10.1603/ME11256
“The bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), has experienced an extraordinary global resurgence in recent years, the reasons for which remain poorly understood. Once considered a pest of lower socioeconomic classes, bed bugs are now found extensively across all residential settings, with widespread infestations established in multiapartment buildings. Within such buildings, understanding the population genetic structure and patterns of dispersal may prove critical to the development of effective control strategies. Here, we describe the development of 24 high-resolution microsatellite markers through next generation 454 pyrosequencing and their application to elucidate infestation dynamics within three multistory apartment buildings in the United States. Results reveal contrasting characteristics potentially representative of geographic or locale differences. In Raleigh, NC, an infestation within an apartment building seemed to have started from a single introduction followed by extensive spread. In Jersey City, NJ, two or more introductions followed by spread are evident in two buildings. Populations within single apartments in all buildings were characterized by high levels of relatedness and low levels of diversity, indicative of foundation from small, genetically depauperate propagules. Regardless of the number of unique introductions, genetic data indicate that spread within buildings is extensive, supporting both active and human-mediated dispersal within and between adjacent rooms or apartments spanning multiple floors.”
Saenz, V. L., W. Booth, C. Schal, and E. L. Vargo. 2012. Genetic analysis of bed bug populations reveals small propagule size within individual infestations but high genetic diversity across infestations from the Eastern United States. Journal of Medical Entomology. 49: 865–875. doi: http://dx.doi.org/10.1603/ME11202
“Bed bugs (Cimex lectularius L.) are a resurgent pest worldwide and infestations within the United States are increasing at a rapid rate. Because of the physical and psychological discomfort inflicted by their blood feeding habits, and allergies and secondary infections associated with bites, bed bugs are recognized as a significant public health problem. Although bed bug infestations are spreading and becoming more prevalent, we have a poor understanding of their dispersal patterns and sources of infestation. To help fill this gap, we conducted a genetic study of 21 bed bug infestations from the Eastern United States, nearly all of which came from single rooms within residences. We genotyped samples comprised of 8-10 individuals per infestation at nine polymorphic microsatellite loci. Despite high genetic diversity across all infestations, with 5-17 alleles per locus (mean = 10.3 alleles per locus), we found low genetic diversity (1-4 alleles per locus) within all but one of the infestations. These results suggest that nearly all the studied infestations were started by a small propagule possibly consisting of a singly mated female and/or her progeny, or a female mated with multiple males that were highly related to her. All infestations were strongly genetically differentiated from each other (mean pairwise F(ST) between populations = 0.68) and we did not find strong evidence of a geographic pattern of genetic structure, indicating infestations located in closer proximity to each other were nearly as genetically differentiated as those located hundreds of kilometers away. The high level of genetic diversity across infestations from the eastern United States together with the lack of geographically organized structure is consistent with multiple introductions into the United States from foreign sources.”
Schaafsma, E. J., S. D. Hapke, and M. G. Banfield. 2012. Bed bug (Cimex lectularius L.) population composition as determined by baited traps. Insects. 3: 442–452. doi: 10.3390/insects3020442
“Two established field populations of bed bugs were sampled using host-mimicking traps baited with a combination of CO2, heat and a synthetic kairomone. The proportion of first instar nymphs (between 52% and 78% of all captured insects) was significantly higher than reported in previous studies, which had employed different sampling methods. The proportion of adults was correspondingly much lower than previously reported, between 5% and 7% of total capture. As many as 120 bed bugs were captured in a single trap in one night; the variation in catches between sampling locations within the same room and between days at the same location indicates that multiple nights of trapping may be required to obtain an accurate representation of population structure.”
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
“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). Analysis of a survivorship and fecundity life table for the RR strain produced the following results. 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. Analysis of daily reproductive parity showed that females produced 1–3 and 4–6 eggs on 79 and 21% of the days, respectively, when egg laying occurred. The net reproductive rate (R0) of the RR strain was ~35, which represents a 35-fold increase in the population per generation (~92 days). The intrinsic rate of increase, r, was 0.054 indicating that the population multiplies 1.1 times/female/day (λ) and doubles in size every 13 days. The stable age distribution (cx) was dominated by nymphs (54%), followed by eggs (34%) and adults (12%). Reproductive values (vx) for the strain increased from egg to the adult stage.”
Wang, C., and X. Wen. 2011. Bed bug infestations and control practices in China: implications for fighting the global bed bug resurgence. Insects. 2: 83–95. doi: 10.3390/insects2020083
“The bed bug resurgence in North America, Europe, and Australia has elicited interest in investigating the causes of the widespread and increasing infestations and in developing more effective control strategies. In order to extend global perspectives on bed bug management, we reviewed bed bug literature in China by searching five Chinese language electronic databases. We conducted telephone interviews of staff from 77 Health and Epidemic Prevention Stations in six Chinese cities in November 2010. We also conducted telephone interviews of 68 pest control firms in two cities during March 2011. Two species of bed bugs (Cimex lectularius L. and Cimex hemipterus (F.)) are known to occur in China. These were common urban pests before the early1980s. Nationwide “Four-Pest Elimination” campaigns (bed bugs being one of the targeted pests) were implemented in China from 1960 to the early 1980s. These campaigns succeeded in the elimination of bed bug infestations in most communities. Commonly used bed bug control methods included applications of hot water, sealing of bed bug harborages, physical removal, and applications of residual insecticides (mainly organophosphate sprays or dusts). Although international and domestic travel has increased rapidly in China over the past decade (2000–2010), there have only been sporadic new infestations reported in recent years. During 1999–2009, all documented bed bug infestations were found in group living facilities (military dormitories, worker dormitories, and prisons), hotels, or trains. One city (Shenzhen city near Hong Kong) experienced significantly higher number of bed bug infestations. This city is characterized by a high concentration of migratory factory workers. Current bed bug control practices include educating residents, washing, reducing clutter, putting items under the hot sun in summer, and applying insecticides (pyrethroids or organophosphates). There have not been any studies or reports on bed bug insecticide resistance. Difficulties of control were noted in our surveys of dormitories in which crowded living, seasonal worker migration, and financial constraints contributed to control failures. This study supports the following conclusions: (1) the bed bug infestation in China dramatically decreased following the campaigns from 1960 to the early 1980s; (2) In our survey of Health and Epidemics Prevention Stations, no bed bug cases were reported in Beijing and Shanghai for the past 12 months, but complaints were reported in Guangzhou, Lanzhou, Urumqi, and Shenzhen; (3) Current bed bug infestations primarily are reported in crowded living environments or transient environments such as worker dormitories and military dormitories. These findings suggest that community-wide bed bug monitoring and control campaigns are necessary for effective control of bed bug infestations as a societal response.”
Doggett, S. L., and R. C. Russell. 2008. The resurgence of bed bugs, Cimex spp. (Hemiptera: Cimicidae) in Australia. 6th International Conference on Urban Pests, Budapest, Hungary, 13-16 July 2008. 407–425.
“From 2001 to 2004, Australia experienced a resurgence in bed bug infestations involving both the common (Cimex lectularius) and Tropical (Cimex hemipterus) species. It was found that all Australian mainland states had experienced an exponential rise in bed bug infestations since 2001, with an overall national increase of 4.5%. A conservative estimate of the economic impact of the resurgence was $AUS100 million. To combat the resurgence, a four point strategy was implemented. The first strategy was to better define the degree of the resurgence through a survey of professional pest managers. The second strategy was the defining of best practice in bed bug management, which led to the development in 2005 of a Code of Practice for the Control of Bed Bug infestations in Australia (CoP) (www.bedbug.org.au). The aims of the CoP were to promote best practice in the eradication of active bed bug infestations and the management of potential infestations. Education of stakeholders affected by bed bugs on best practice management as defined by the CoP was the third strategy and encompassed the production of industry publications and lectures. Research, and investigations have begun in relation to both non-chemical and chemical means of control.”