Population Genetic Analysis of Host Seeking and Resting Behaviors in the Malaria Vector, Anopheles balabacensis (Diptera: Culicidae) J.L.K. HII, 1 M. CHEW, V. Y. SANG, L. E. MUNSTERMANN, 2 S. G. TAN, 3 S. PANYIM, 4 AND S. YASOTHORNSRIKUL 4 Tropical Diseases Research Laboratory, Department of Medical Services, 88814 Kota Kinabalu, Sabah, Malaysia J. Med. Entomol. 28(5): 675-684 (1991) ABSTRACT During the intermonsoon period from mid-September to mid-October 1986, wild-caught Anopheles balabacensis Baisas females were marked and released in a host- choice experiment. Association between capture and recapture of marked mosquitoes from human and bovid hosts and blood meal host identification of recaptured females were determined on a daily basis. Although the mark-recapture and blood meal data indicated behavioral heterogeneity between buffalo and human biters, restriction endonuclease frag- ment length polymorphism analysis revealed no differences in repeat sequence profiles. Doubly-marked recaptures strongly indicated a "learning" component involved in a separate host preference experiment. In a "habitat loyalty" experiment conducted in January 1987, females of An. balabacensis preferentially returned to the resting sites (indoor surfaces and exit traps) where they were first caught. Of nine isozyme loci found to be polymorphic, the genotypic frequencies of Esterase-3 and Isocitrate denydrogenase-3 were different in "faith- fully" endophilic and exophilic subpopulations. Genetic heterozygosity, as determined by polyacrylamide gel electrophoresis, was greater in exophilic than endophilic population components. These results confirm that genetic and learning components can significantly influence house resting and host seeking behavior and may contribute to local epidemiological patterns of malaria transmission observed in Sabah, Malaysia. KEY WORDS Insecta, Anopheles balabacensis, population genetics, mark-recapture GENETICAL STUDIES of the behavior of medically important insects are of increasing interest to evo- lutionary and applied biologists. Recently, individ- ual variation in host or habitat preference has been examined for several mosquito species to better understand their ecology. Genetical heterogeneity has been observed among population subsamples collected from different hosts and habitats for some (e.g., Aedes aegypti (L.) in Trpis & Hausermann 1975, Aedes simpsoni (Theo.) in Mukwaya 1974, Anopheles balabacensis Baisas in Hii 1985), but not all species (An. culicifacies Giles in Rawlings & Curtis 1982, An. gambiae Giles in Lines et al. 1986, An. punctulatus Donitz complex in Charl- wood et al. 1986). In Thailand, population genetic analysis revealed a complex of species within An. minimus Theobald (Sucharit et al. 1988, Green et al. 1990), but did not fully explain previous obser- vations of behavioral and physiological heteroge- neities within this taxon (Nutsathapana et al. 1986a, b). Some controversy has been created by two stud- 1 Current address: Papua New Guinea Institute of Medical Re- search, P.O. Box 378, Madang, Papua New Guinea. 2 Vector Biology Laboratory, University of Notre Dame, Notre Dame, Ind. 46556. 3 Department of Biology, Universiti Pertanian Malaysia, Ser- dang, Selangor, Malaysia. 'Department of Biochemistry, Faculty of Science, Mahidol Uni- versity, Bangkok, Thailand. ies linking allele frequencies with an environmen- tal variable in the tree-hole mosquito, Ae. triser- iatus Say in North America. Saul et al. (1978) found a significant correlation between larval habitat in oak rot holes versus beech pans and the frequency of two esterase alleles (of the Est-6 locus) in wild Ae. triseriatus populations. However, in attempts to repeat these results, the postulated association between larval habitat and the Est-6 alleles was not confirmed (Matthews 1983). The existence of two cryptic species within Anopheles balabacensis was suspected in Sabah (Hii 1985). Mark-recapture experiments demon- strated significant behavioral heterogeneity with respect to host seeking and indoor resting. Similar results were obtained by changing and rotating the positions of man and water buffalo hosts every night (Hii & Vun 1987). Possible explanations may be intraspecific polymorphism, or a learning compo- nent for habitat or host selection. Using the crite- rion of positive assortative mating, these subpo- pulations also may qualify as sibling species because of incompatible mate recognition systems (sensu Paterson 1982) and therefore, genetic divergence may be expected. To test for this genetic diver- gence, the mark-recapture experiments were re- peated and combined with a study of enzyme elec- trophoresis and restriction fragment length polymorphism. 0022-2585/91/0675-0684$02.00/0 © 1991 Entomological Society of America Downloaded from https://academic.oup.com/jme/article/28/5/675/2220970 by guest on 04 June 2022