The Pennsylvania State University The Graduate School College of Agricultural Sciences SPECIES-SPECIFICITY OF THREE COMMONLY USED AND TWO NOVEL MOSQUITO FIELD-SAMPLING DEVICES A Thesis in Entomology by Loyal Philip Hall © 2012 Loyal Philip Hall Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science May 2012 ii The thesis of Loyal Philip Hall was reviewed and approved* by the following: Gary Felton Professor and Department Head of Entomology Thomas Baker Distinguished Professor of Entomology Thesis Advisor James Marden Professor of Biology Michael Saunders Professor of Entomology Matthew Thomas Professor of Entomology *Signatures are on file in the Graduate School. iii Abstract Effective sampling is a stepping-stone to efficient use of resources, targeted control efforts, and success in nuisance or vector mosquito management. Effective sampling to identify locations where disease-vectoring mosquitoes are present and to monitor population levels allows control measures to be targeted towards medically important mosquitoes, and can reduce the environmental and financial costs associated with widespread, indiscriminate pesticide application while also preventing the failure to initiate control in an area due to a perception that there are few important mosquitoes present. A comparative study between the CDC light trap, ABC light trap, Reiter-Cummings gravid trap, and two traps developed by the author was conducted to test for species-specificity of each trap type. It was found that while no trap was superior over-all, certain species of mosquitoes are more likely to be detected and their populations monitored by some types of traps compared to others and the novel traps were shown to often be as effective in sampling certain important target species of mosquito as the tested commercial mosquito traps. As with the other devices, for some species the novel traps were superior and for others they appeared to be a less effective sampling device. For example, Co. perturbans tended to prefer CDC light traps, Cx. salinarius tended to prefer Hall light traps, and Cx. pipiens tended to prefer Hall gravid and Reiters-Cummings gravid traps over the other traps included in the study. 14 different species were analyzed for trap preference; results were also analyzed for WNV-infections and variety of species. iv Contents List of Figures v List of Tables vii List of Abbreviations viii Acknowledgements ix Chapter 1, An introduction to mosquito sampling 1 Chapter 2. Species specificity of three commonly used mosquito sampling devices and two novel devices in the field. 9 Introduction 9 Materials and Methods 10 Results 18 Discussion 36 References 43 Appendix A: Number of Mosquitoes In Each Trap Type By Species 46 Appendix B: Minitab Output of Statistical Tests 47 v Figures Chapter 1. Figure 1. Larvae. Figure 2. Pupae. Figure 3. Standard dipper Figure 4. New Jersey light trap Figure 5. ABC and CDC light traps Figure 6. Reiter-Cummings gravid trap Chapter 2. Figure 7. Hall trap base Figure 8. Hall light trap Figure 9. Hall gravid trap Figure 10. ABC light trap Figure 11. CDC light trap Figure 12. RC gravid trap Figure 13. A typical set-up of a randomized complete block Figure 14. Histogram of the number of individuals of each species caught at a wastewater treatment plant site using the data from all 5 trap-types combined Figure 15. Histogram of the number of individuals of each species caught at a human-made wetland site using the data from all 5 trap-types combined Figure 16. Histogram of the number of individuals of each species caught at a wooded site prone to flooding using the data from all 5 traps combined Figure 17. Mean number of Culex pipiens captured per trap in the five different trap-types Figure 18. Mean number of Culex restuans captured per trap in the five different trap types Figure 19. Mean number of Culex salinarius captured per trap in the five different trap types Figure 20. Mean number of WNV-positive sub-samples per trap in the five different trap- types Figure 21. Mean number of Ochlerotatus trivitattus captured per trap in the five different trap-types Figure 22. Mean number of Aedes vexans captured per trap in the five different trap-types Figure 23. Mean number of Psorophora ferox captured per trap in the five different trap- types Figure 24. Mean number of Anopheles quadrimaculatus captured per trap in the five different trap-types Figure 25. Mean number of Coquillettidia perturbans captured per trap in the five different trap-types Figure 26. Mean number of Anopheles punctipennis captured per trap in the five different trap-types Figure 27. Mean number of Ochlerotatus canadensis captured per trap in the five different trap-types Figure 28. Mean number of Ochlerotatus japonicus captured per trap in the five different trap-types Figure 29. Mean number of Ochlerotatus triseriatus captured per trap in the five different trap-types Figure 30. Mean number of Psorophora columbiae captured per trap in the five different trap-types vi Figure 31. Mean number of Psorophora horrida captured per trap in the five different trap- types. Figure 32. Mean number of mosquitoes, for all species combined, captured per trap in the five different trap-types Figure 33. Mean number of different species captured per trap in the five different trap-types Figure 34. Mean number of species (non- Culex pipiens/restuans) captured per trap in the five different trap-types vii Tables Table 1. Number of mosquitoes in each trap type by species A Table 2. Number of mosquitoes in each trap type by species B Table 3. Number of mosquitoes in each trap type by species C Table 4. Raw two-way ANOVA test results. viii Abbreviations ABC American Biophysics Corporation Ae. Aedes An. Anopheles CDC Centers for Disease Control Co. Coquillettidia Cx. Culex EEE Eastern Equine Encephalitis Och. Ochlerotatus Ps. Psorophora RC Reiters-Cummings WNV West Nile Virus ix Acknowledgements. The Pennsylvania West Nile Program was instrumental to the success of this study. Their laboratory performed all of the identifications with the highest levels of skill and professionalism. The management allowed the use of this valuable Commonwealth resource because they saw the value in this study and the benefit it could bring to disease management and making their own program more effective at protecting human and animal health. 1 Chapter 1. An overview concerning mosquito sampling. Mosquito-vectored diseases, including malaria, yellow fever, eastern equine encephalitis, and West Nile virus, among others, kill millions of people each year and sicken hundreds of millions more. These numbers make mosquitoes the deadliest animals on earth. According to the Centers for Disease Control, a major priority in combating mosquito-vectored diseases is controlling mosquito populations through integrated pest management practices that incorporate surveillance, habitat modification, and changes in human behavior, along with pesticide applications that employ the least environmentally damaging yet effective control products available (Gubler et al., 2003). Effective sampling to identify locations where disease-vectoring mosquitoes are present and to monitor population levels allows control measures to be targeted towards medically important mosquitoes, and can reduce the environmental and financial costs associated with widespread, indiscriminate pesticide application while also preventing the failure to initiate control in an area due to a perception that there are few medically important mosquitoes present. The goal when sampling mosquitoes is to develop an accurate picture of the population of important species. There may be dozens of species present in a particular area. However, only certain species are important to a mitigation program or to public health officials. This study focuses on determining the efficacy of widely used mosquito sampling devices along with experimental devices developed by the author for specific mosquito species. Pennsylvania is well suited to mosquito studies. It is on the frost line, and here the ranges of northern and southern species overlap. The geologic history of the region has resulted in a wide variety of ecosystems located in close proximity. Human development of large swaths of land has resulted in the fracturing of natural habitats, reducing predators and allowing r- 2 strategists, like mosquitoes, to flourish. These urbanized areas provide prime habitats for many anthropophilic species. This all results in a large variety of disease-vectoring and nuisance species in Pennsylvania, where 59 species of mosquito are recognized by the state’s West Nile Virus Program. In Pennsylvania and the surrounding areas, several mosquito-vectored maladies are endemic, including West Nile virus (WNV), St. Louis encephalitis (SLE), LaCrosse encephalitis, eastern equine encephalitis (EEE), and dog heartworm. The introduction/reintroduction of other mosquito-vectored diseases is a concern of the state’s WNV program with the increase in international travel and invasive species. Malaria and chikungunya have appeared in sporadic outbreaks in border states. Dengue is a concern for introduction due to the invasive species Aedes albopictus that is now common in many parts of Pennsylvania, although it is currently not found in Lebanon County where the trials reported herein were conducted. There are many methods for sampling mosquitoes. Because mosquitoes have an aquatic larval stage and a flying adult stage the sampling processes can be divided into adult and larval sampling techniques. Mosquito larvae are aquatic, but do breathe air. Many genera, Figure 1. Larvae. such as Culex and Aedes have a snorkel-like “siphon” on their dorsal posterior, whereas the genera Anopheles simply have spiracles in the same location through which they breathe (Fig. 1). Pupae of all species have two breathing tubes located dorsally called “trumpets” (Fig. 2). Most Figure 2. Pupae. mosquito larvae and pupae hang on the surface tension of the water, with their breathing apparatus exposed to the air and the rest of the organism under water.