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Journal of Medical Entomology 47(5):791-797. 2010 doi: 10.1603/ME10001 Geographic Distribution of Stomoxyine Flies (Diptera: Muscidae) and Diurnal Activity of Stomoxys calcitrans in Thailand Muenworn, V.a , Duvallet, G.b , Thainchum, K.a , Tuntakom, S.c , Tanasilchayakul, S.c , Prabaripai, A.d , Akratanakul, P.a e , Sukonthabhirom, S.f , Chareonviriyaphap, T.a a Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand Centre d'Ecologie Fonctionnelle et Évolutive (Unit Mixte de Recherche 5175), Université de Montpellier, 20 Montpellier, France c Department of Entomology, Kamphaengsean, Campus, Kasetsart University, Nakhon Pathom 73140, Thailand d Division of Biostatistics and Computer, Kamphaengsean Campus, Kasetsart University, Nakhon Pathom 73140, Thailand e Center for Agricultural Biotechnology, Kasetsart University, Bangkok 10900, Thailand f Office of Plant Protection Research and Development, Department of Agriculture, Ministry of Agriculture and Cooperative, Bangkok 10900, Thailand b ABSTRACT Stomoxyine flies (Stomoxys spp.) were collected in 10 localities of Thailand using the Vavoua traps. These localities represented four major ecological settings, as follows: small local dairy farms, large industrial dairy farms, a national park, and one elephant conservation area. Three species of stable flies were identified in the following proportions: Stomoxys calcitrans (91.5%), Stomoxys indicus(7.9%), and Stomoxys sitiens (0.6%). The number of flies collected differed significantly among collection sites (χ2 = 360.15, df = 3, P < 0.05). The greatest number of stomoxyine flies was captured in dairy farms, Seasonal and daily activity of S. calcitrans was observed during a 1-yr period at two selected locations (Dairy Farming Promotion Organization of Thailand and Khao Kheow Open Zoo).S. calcitrans was more abundant during the rainy season (March–September), but was not associated with the total rainfall (r2 = 0.0002, P > 0.05). Peak of daily flight activity of males S. calcitrans was at 1000 and 1600 h, whereas females showed an increase of activity all along the day until 1600 h. A better understanding of stomoxyine fly behavior related to patterns of daily activity will facilitate and improve the efficiency of fly control measures in private and government sectors. Keywords: Stomoxys spp, distribution, seasonal and diurnal activity, Vavoua traps, Thailand Journal of Medical Entomology 47(5):823-832. 2010 doi: 10.1603/ME09016 Human-Landing Patterns of Anopheles dirus sensu lato (Diptera: Culicidae) in Experimental Huts Treated with DDT or Deltamethrin Malaithong, N.a , Polsomboon, S.a , Poolprasert, P.a , Parbaripai, A.b , Bangs, M.J.c , Suwonkerd, W.d , Pothikasikorn, J.e , Akratanakul, P.a f , Chareonviriyaphap, T.a a Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand Faculty of Liberal Art and Science, Kasetsart University, Kamphaengsean, Nakhonprathom 73140, Thailand c Public Health and Malaria Control, Jl. Kertajasa, Kuala Kencana, Papua 99920, Indonesia d Department of Disease Control, Ministry of Public Health, Nonthaburi 10100, Thailand e Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand f Centre for Agricultural Biotechnology, Kasetsart University, Bangkok 10900, Thailand b ABSTRACT Anopheles dirus females landing on humans inside experimental huts treated with residual applications of DDT or deltamethrin were observed during the wet season in Pu Teuy Village, Kanchanaburi Province, western Thailand. Two identical experimental huts were constructed in the fashion of typical local rural Thai homes. Pretreatment (baseline) human-landing collections (HLC) in both huts showed an early evening peak of activity between 1900 and 2000 h with no significant difference in numbers of mosquitoes captured between huts over a period of 30 collection nights. During posttreatment HLC, female mosquitoes continued to show greater landing activity inside huts fitted with insecticide-treated panels during the first half of the evening compared with the second half. A greater number (proportion) of An. dims females landed on humans in the hut treated with deltamethrin compared with DDT. Comparing pre- and posttreatment HLC, the DDT-treated hut showed a 79.4% decline in attempted blood feeding, whereas exposure to deltamethrin resulted in a 56.3% human-landing reduction. An odds ratio was performed to demonstrate the relative probability (risk) of mosquitoes entering and attempting to blood feed in the two treated huts compared with untreated control huts. Mosquitoes were ≈times less likely to land on humans inside a DDT-treated hut compared with the deltamethrin-treated hut. Although both chemicals exerted strong excitatory responses, DDT appears to have a more pronounced and significant (P = 0.002) effect on behavior than deltamethrin, resulting in greater movement away from the insecticide source and thus potential reduction of blood-feeding activity. Keywords: Anopheles dims, behavioral response, experimental hut, deltamethrin, DDT Journal of Economic Entomology 103(3):1012-1018. 2010 doi: 10.1603/EC09012 Population Structure of Stomoxys calcitrans (Diptera: Muscidae) From Nine Regions of Thailand Tainchum, K.a b , Sukonthabhirom, S.c , Duvallet, G.d , Akratanakul, P.a b , Muenworn, V.a , Chareonviriyaphap, T.a a Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand Center for Agricultural Biotechnology (AG-BIO/PERDO-CHE), Thailand c Office of Plant Protection Research and Development, Department of Agriculture, Ministry of Agriculture and Cooperative, Bangkok 10900, Thailand d Centre d'Écologie Fonctionnelle et Évolutive (CEFE), UMR 5175, Université Paul Valéry, Route de Mende, 34199 Montpellier cedex 5, France b ABSTRACT Starch gel electrophoresis of isozymes was used to estimate gene flow among nine populations ofStomoxys calcitrans (L.) (Diptera: Muscidae) from Thailand. Of the 13 putative loci, nine polymorphic loci were detected. Limited genetic differentiation among populations was observed (FST= 0.060). The highest level of polymorphism was observed in flies from eastern Trat and northern Chiang Mai provinces (69.2%), whereas the lowest level of polymorphism was seen in flies from central Saraburi Province (23.1%). Gene flow between populations varied from 3.27 to 27.53 reproductive migrants per generation. Among the nine populations sampled, no correlation was seen between genetic and geographical distances showing that sampled S. calcitrans fit closely in the same cluster taxa. The electrophoresis of ten isozymes shows a genetic homogeneity of S. calcitranspopulations at the scale of Thailand. Keywords: Stomoxys cahitrans, genetics, isozyme, gene flow, Thailand Kasetsart Journal - Natural Science 43 (3), pp. 526-537.2009 Genetic diversity and gene flow among stable fly populations,stomoxys calcitrans (L.) in Thailand Tainchum, K.a , Duvallet, G.b , Akaratanakul, P.a c , Chareonviriyaphap, T.a a Department of Entomology, Faculty of Agriculture, Kasestart University, Bangkok 10900, Thailand Centre d'Écologie Fonctionnelle et.. .volutive (CEFE), UMR 5175, Université Paul Valéry, Route de Mende, 34199 Montpellier cedex 5, France c Center for Biotechnology, Kasetsart University, Bangkok 10900, Thailand b Abstract Isozymes from five wild-caught Stomoxys calcitrans (L.) were compared using starch gel electrophoresis to estimate the rates of gene flow between and among S. calcitrans populations from five different geographic regions of Thailand. Among ten enzyme systems, 13 putative loci and 10 polymorphisms were detected. Limited genetic differentiation among the five populations was observed as indicated by the low Fsτ (0.078). The highest percentage of polymorphic loci was observed in eastern Trat province and northern Chiang Mai province (69.2%), whereas the lowest percent polymorphism was seen in south-central Saraburi province (23.1%). Gene flow between populations varied from 6.16 to 15.38 reproductive migrants per generation with no fixed genetic differences detected. Among the five population samples, no correlation was seen between genetic and geographical distances showing that sampled S. calcitrans fit closely in the same cluster taxa. The genetic and epidemiological ramifications of these findings are discussed. Keywords:Gene flow; Genetics; Isozyme; Stomoxys calcitrans; Thailand Journal of Vector Ecology 33(1): 158-165 . 2008 Genetic structure and gene flow of Anopheles minimus and Anopheles harrisoni in Kanchanaburi Province, Thailand Poolprasert, P.a , Manguin, S.b , Bangs, M.J.c , Sukhontabhirom, S.a , Poolsomboon, S.a , Akaratanakul, P.a d , Chareonviriyaphap, T.a a Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand Institut de Recherche pour le Developpement (IRD), UMR22 Centre de Biologie et de Gestion des Populations (CBGP), Campus de Baillarguet CS30016, Montferrier sur Lez 34988, France c Public Health and Malaria Control, Kuala Kencana-Timika, Papua 99920, Indonesia d Center of Agricultural Biotechnology, Kasetsart University, Bangkok 10900, Thailand b Abstract Isozyme frequencies were compared in seven field collections of Anopheles minimus complex using starch gel electrophoresis. Mosquito collections were sampled from four districts in Kanchanaburi Province where malaria is endemic. From eight enzyme systems, nine loci and seven polymorphisms were detected, indicating limited genetic differentiation among the seven collections (FST = 0.061). The highest percent polymorphic loci were observed in Bong Ti Noi (BTN) Village (55.6%), whereas the least percent polymorphism was seen in Tha Kradan (TK) Village (22.2%). Comparing villages Pra Jedee (PJ) with PuTeuy C (PTC) and Huai Khayeng (HK) with Pra Jedee (PJ), gene flow among collections varied from 3.72 to 62.25 reproductive migrants per generation. Among the seven collections, no correlation was seen between genetic and geographical distances (P > 0.05). Anopheles minimus (former species A) and Anopheles harrisoni (former species C) from Pu Teuy fit most closely in the same cluster, possibly indicating relatively recent divergence between taxa. The genetic and epidemiological ramifications of these findings are discussed. Keywords: Anopheles harrisoni; Anopheles minimus; Gene flow; Genetic; Isozyme; Malaria; Thailand Journal of Vector Ecology 33(2):285-292. 2008 doi: 10.3376/1081-1710-33.2.285 Biting patterns of Anopheles minimus complex (Diptera: Culicidae) in experimental huts treated with DDT and deltamethrin Polsomboon, S.a , Poolprasert, P.a , Suwonkerd, W.b , Bangs, M.J.c , Tanasinchayakul, S.d , Akratanakul, P.a e , Chareonviriyaphap, T.a a Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand Department of Disease Control, Ministry of Public Health, Nonthaburi 10000, Thailand c Public Health and Malaria Control, Jl. Kertajasa, Kuala Kencana-Timika, Papua, 99920, Indonesia d Department of Entomology, Faculty of Agriculture, Kasetsart University, Nakhon Pathom 73140, Thailand e Center for Agricultural Biotechnology, Kasetsart University, Bangkok 10900, Thailand Abstract b Biting patterns of natural populations of Anopheles minimus s.l. females entering experimental huts treated with DDT and deltamethrin were carried out at Pu Teuy Village, Sai Yok District, Kanchanaburi Province, western Thailand. Two experimental huts, control and treatment, were constructed in the fashion of local Thai homes. Pre-spray biting activity of An. minimus females peaked at 19:00–22:00. Post-treatment exposure continued to show greater landing activity during the first half of the evening. An overall greater proportion of An. minimus females entered the hut treated with deltamethrin compared to DDT. The hut fitted with DDT-treated net panels showed a 71.5% decline in attempted blood feeding, whereas exposure to deltamethrin-treated panels resulted in a 42.8% human-landing reduction. DDT exhibited significantly more pronounced (P < 0.05) effects in overall reduction of biting activity than did deltamethrin. Keywords: Anopheles minimus, behavioral responses, excito-repellency, experimental hut, deltamethrin,DDT Journal of Vector Ecology 31 (2), pp. 266-274.2006 Susceptibility and avoidance behavior by Culex quinquefasciatus say to three classes of residual insecticides Sathantriphop, S.a e , Ketavan, C.a , Prabaripai, A.b , Visetson, S.c , Bangs, M.J.d , Akratanakul, P.a f , Chareonviriyaphap, T.a a Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand Faculty of Liberal Arts and Science, Kasetsart University, Kampheangsean, Nakhon Pathom 73140, Thailand c Department of Zoology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand d Navy Disease Vector Ecology and Control Center, 2850 Thresher Avenue, Silverdale, WA 98315, United States e National Institute of Health, Ministry of Public Health, Nonthaburi 11000, Thailand f Center of Agricultural Biotechnology, Kasetsart University, Bangkok 10900, Thailand b ABSTRACT The behavioral responses of three colonized strains of Culex quinquefasciatus, two from recent field collections in Thailand (Nonthaburi and Mae Sot) and one from a long-established colony from the National Institute of Health (NIH), Ministry of Public Health, Thailand, were compared during and after exposure to deltamethrin (0.02 g/m2), propoxur (0.2 g/m2), and fenitrothion (0.2 g/m2) using an excito-repellency escape chamber system. We observed striking differences in behavioral response and excito-repellency between mosquito strains and test compounds. Greater escape responses were observed in the NIH strain during direct contact with deltamethrin and fenitrothion compared with the two field populations. Deltamethrin was the most irritant, followed by fenitrothion. Escape responses with propoxur were significantly delayed but increased slightly towards the end of the 30min exposure period, more notably in the Nonthaburi strain (P<0.05). Non-contact repellent responses were generally much weaker than irritancy, with the greatest escape response seen with NIH and Nonthaburi. Deltamethrin showed the weakest repellent response overall (< 10% escape), while propoxur again demonstrated a delayed effect (NIH and Mae Sot) before escape occurred. We conclude that irritant and repellent behavioral responses by Cx. quinquefasciatus are important components for assessing the impact of residual spraying in mosquito control programs. A better understanding of chemical properties that elicit behavioral responses in mosquitoes should be considered in formulating control strategies designed to control mosquitoes or mitigate disease transmission risk. Keywords: Behavioral avoidance; Culex quinquefasciatus; Deltamethrin; Excito-repellency; Fenitrothion; Propoxur Journal of Vector Ecology 31 (1), pp. 89-101.2006 Influence of nutritional and physiological status on behavioral responses of Aedes aegypti (Diptera: Culicidae) to deltamethrin and cypermethrin Chareonviriyaphap, T.a , Kongmee, M.a , Bangs, M.J.b , Sathantriphop, S.a , Meunworn, V.a , Parbaripai, A.c , Suwonkerd, W.d , Akratanakul, P.a e a Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand U.S. Naval Medical Research Unit No. 2, Jl. Percetakan Negara 29, Jakarta 10560, Indonesia c Division of Computer and Biostatistics, Faculty of Liberal Arts and Science, Kasetsart University, Kampheangsean, Nakhonphatom 73140, Thailand d Center of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nontaburi 11000, Thailand e Center of Agricultural and Biotechnology, Kasestart University, Bangkok 10900, Thailand b ABSTRACT Excito-repellency responses of Aedes aegypti (L.) exposed to deltamethrin and cypermethrin were assessed using an excito-repellency test system. Contact irritancy and non-contact repellency assays compared non-bloodfed (unfed) parous (post-gravid), nulliparous, early blood-fed, late blood-fed, sugar-fed, and unmated female mosquitoes for behavioral responses based on nutritional and physiological conditions at the time of testing. Rates of escape during contact exposure with either compound were most pronounced in parous mosquitoes, followed by unmated mosquitoes, when compared to other conditional states. Significantly higher numbers of parous females also escaped from control chambers compared to other cohorts (P<0.05). Irritability of blood- and sugar-fed mosquitoes was noticeably suppressed. We conclude that nutritional and physiological conditions (including age) of mosquitoes at the time of testing can significantly influence behavioral responses (excito-repellency) to insecticides. The findings indicate that whether due to chronological age, nutrition, physiological state, or innate (circadian) activity patterns, careful consideration must be given to the selection of appropriate conditioned mosquitoes for testing. Keywords: Aedes aegypti; Behavior; Cypermethrin; Deltamethrin; Excito-repellency Journal of Medical Entomology 41(6):1055-1063. 2004 doi: 10.1603/0022-2585-41.6.1055 Behavioral Responses of Aedes aegypti (Diptera: Culicidae) Exposed to Deltamethrin and Possible Implications for Disease Control Kongmee, M.a , Prabaripai, A.b , Akratanakul, P.a c , Bangs, M.J.d , Chareonviriyaphap, T.a a b c d Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand Faculty of Liberal Arts and Science, Kasetsart University, Nakhonpathom, 73140, Thailand Ctr. for Agricultural Biotechnology, Kasetsart University, Bangkok, 10900, Thailand U.S. Nav. Medical Research Unit No.2, Jl. Percetakan Negara No. 29, Jakarta, 10560, Indonesia Abstract Behavioral responses of nine Aedes aegypti (L.) strains, six from recent field collections and three from the long-established laboratory colonies, were tested under laboratory-controlled conditions by using an excito-repellency test system. All nine strains showed significant behavioral escape responses when exposed to deltamethrin at the standard field dose (0.02 g/m2), regardless of background insecticide susceptibility status (susceptible or tolerant/resistant). Insecticide contact irritancy played a predominate role in overall female mosquito escape responses, whereas noncontact repellency was not observed at levels significantly different from paired noncontact control tests (P > 0.01). Among the six field populations, the Jakarta (Indonesia) Toba (north Sumatra), and Bangkok female mosquitoes showed rapid exit (>78%) during 30 min of direct contact with insecticide-treated surfaces, whereas the other three strains demonstrated only moderate escape responses (32–56%) from the chambers. Moderate escape responses during direct insecticidal contact also were observed in the three laboratory test populations (44–60%). Higher percentage of mortality was observed from laboratory strains (8–33%) that failed to escape compared with nonescape females of field strains (2– 16%), possibly a reflection of background deltamethrin susceptibility status. We conclude that contact irritancy is a major behavioral response of Ae. aegypti when exposed directly to deltamethrin and that rapid flight escape from areas exposed to space sprays or surfaces treated with residual pyrethroids could have a significant impact on the effectiveness of adult mosquito control and disease transmission reduction measures. Keywords: Aedes aegypti, behavioral avoidance, excito-repellency, deltamethrin Journal of Medical Entomology 41(4):657-663. 2004 doi: 10.1603/0022-2585-41.4.657 Allozyme Patterns of Aedes albopictus, a Vector of Dengue in Thailand Chareonviriyaphap, T.a , Akratanakul, P.a b , Huntamai, S.a , Nettanomsak, S.a , Prabaripai, A.a c a Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkean, Bangkok 10900, Thailand b Center of Agricultural Biotechnology, Kasetsart University, Bangkok 10900, Thailand Abstract Isozyme frequencies in six wild-caught populations of Aedes albopictus (Skuse) from various parts of Thailand were compared using starch gel electrophoresis. Four populations were sampled from the south of the country, one from Samui Island and three from the mainland. The remaining two populations were obtained from central (Bangkok) and northern (Tak) Thailand. There were large differences in allele frequencies at two of 22 loci: Glutamate oxaloacetate transminase-2 (Got-2) and Hexokinase-1 (Hk-1). Got-2 (allele 100) was absent from the Bangkok population, whereas it was observed in high frequencies in all other populations. The Bangkok population showed the highest percentage of polymorphic loci (63.6%), whereas the population from Tak demonstrated the smallest percentage of polymorphic loci (18.2%). Keywords: Aedes albopictus, isozymes, dengue vector, Thailand Southeast Asian Journal of Tropical Medicine and Public Health 34 (3), pp. 529-535.2003 Larval habitats and distribution patterns of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse), in Thailand Chareonviriyaphap, T.a c , Akratanakul, P.a b , Nettanomsak, S.a , Huntamai, S.a a Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand Center of Agricultural Biotechnology, Kasetsart University, Bangkok, Thailand c Department of Entomology, Faculty of Agriculture, Kasetsart University, Bang Khen, Bangkok 10900, Thailand b Abstract This study was conducted to survey larval breeding habitats and to obtain larval abundance during the dry period covering all 5 geographical zones of Thailand. Our results indicated Aedes aegypti is prevalent all over the country, whereas Aedes albopictus is more restricted to the remote area of the south. Water storage containers, especially water jars, served as a main larval breeding habitats of Ae. aegypti, whereas broken cans and plastic containers are considered primary breeding sites for Ae. alpopictus during the dry period. In addition, Aedes larval indices, container index (CI), house index (HI), and Breteau index (BI) were measured. CI and HI values from the central part were significantly higher than those from other areas (p<0.01). BI values of all collection sites were greater than 50 (a maximum BI value accepted by the Ministry of Public Health, Thailand). In brief, Ae. aegypti and Ae. albopictus populations heavily infested many towns and residential areas of the country. Drought could not limit the density of Aedes mosquitos in Thailand. Systematic vector control and vector surveillance programs by public health organizations, if practical, should be continuously conducted to reduce or prevent dengue risk. Keywords EMTREE medical terms: Aedes aegypti; Aedes albopictus; article; breeding; container; controlled study; dengue; geographic distribution; habitat quality; habitat selection; infection control; infestation; larva; nonhuman; parasite vector; risk assessment; risk factor; storage; Thailand; water supply MeSH: Aedes; Analysis of Variance; Animals; Dengue; Environment; Insect Control; Insect Vectors; Larva; Population Density; Thailand Proc. VIIth Int. Conf. on Tropical Bees: Management and diversity, and Vth Asian Apicultural Association Conf , pp. 395-398. 2000 Apiculture development in Thailand Akratanakul, P. FAO Agricultural Services Bulletin 68, pp. 95-103. 1986 Beekeeping in Asia Akratanakul, P. American Bee Journal 125, pp. 112-114. 1985 Tropilaelaps clareae, the little known honey bee brood mite Burgett, M., Akratanakul, P. Scientific American 253: 128 – 137. 1985 Yellow Rain Thomas D. Seeley, Joan W. Nowicke, Matthew Meselson, Jeanne Guillemin and Pongthep Akratanaku Proceedings of the Expert Consultation on Beekeeping with Apis Mellifera in Tropical and Subtropical Asia, Bangkok/Chiang Mai, Thailand, 9-14 April 1984 , pp. 222-234 Beekeeping industry with Apis mellifera in Thailand Akratanakul, P. Bee World 64, pp. 25-28. 1983 Tropilaelaps clareae: A parasite of honeybees in south-east Asia Burgett, M., Akratanakul, P., Morse, R.A. Psyche 89, pp. 347-350. 1982 Predation on the Western Honey Bee, Apis Mellifera L., by the Hornet, Vespa Tropica(L.) Michael Burgett1 and Pongthep Akratanakul2 1 Department of Entomology, Oregon State University, Corvallis 97331, Oregon, USA 2 Department of Entomology, Kasetsart University, Kamphaeng Saen, Thailand Ecol. Monogr. 52 (1), pp. 43-63. 1982 Colony defense strategies of the honeybees in Thailand Seeley, T.D., Seeley, R.H., Akratanakul, P. Abstract The colony defense strategies of the three honeybee species in Thailand were studied to examine the influence of predation on tropical honeybee societies. Each species focuses its defenses upon different stages in the predation sequence of detection-approach-consumption. This radiation in defense strategies apparently reflects each species' preadaptation by worker size (small, mediumsized, or large) and nest site (cavity or tree branch) to a different pattern of colony defense. Wasps, birds, and primates probably have difficulty finding the small, dispersed colonies of Apis florea, whose nests are built low on the branches of dense, shrubby vegetation. Once found, however, they are easily approached and overpowered because their low, exposed nests are accessible and their small workers inflict relatively painless stings. When overwhelmed, the bees quickly abandon their nest; later, they return to salvage wax. Ants find A. florea nests easily and at least one species (Oecophylla smaragdina) easily kills these small bees. However, sticky bands of resin encircling the nests' slender substrate branches prevent ants from invading A. florea nests. Cavity-nesting colonies of Apis cerana are conspicuous with their medium-sized bees streaming in and out of low, clearly visible entrance holes in caves and hollow tress. However, gaining access to A. cerana nests is difficult. Large predators cannot pass through the small entrance opening and small predators are overpowered by entrance guards. But if a large predator can breach a nest cavity's walls, it faces an only moderately powerful stinging defense. Apis cerana colonies are relatively small and their workers are not fiercely aggressive. Predators easily find the large, sometimes aggregated colonies of Apis dorsata, whose nests hang in the crowns of the tallest forest trees. But only skilled fliers and climbers can reach these lofty nests. Those which do face massive stinging attacks from the large colonies of these relatively giant, ferocious bees. Nests of both open-nesting species, Apis florea and A. dorsata, are protected by a three- to six-layer curtain of bees over the comb. Apis cerana colonies lack these curtains but are protected by their nest cavity walls. A curtain of inactive guards requires a large labor force. The high worker: brood ratio in A. florea relative to A. cerana colonies suggests that the age polyethism schedules of the open- and cavity-nesting species are tuned differently to generate the appropriate proportions of guard bees. Each species' colony defense system consists of numerous interwoven lines of adaptation, including nest site, nest architecture, colony population, labor allocation to defense, age polyethism schedule, colony mobility, and worker morphology, physiology, and behavior. Predation has been a pervasive and powerful force in the evolution of these tropical bee societies. The Natural History of the Dwarf Honey Bee. 1977 Akratanakul, P. The Natural History of the Dwarf Honey Bee, Apis florea F. in Thailand , pp. 88. 1977 Akratanakul, P. J. Apic. Res. 15, pp. 11-13. 1976 Euvarroa sinhai Delfinado and Baker (Acarina: Mesostigmata) a parasitic mite of Apis florea Akratanakul, P., Burgett, M. American Bee Journal 116 (3), pp. 120-121. 1976 Honey bees in Thailand Akratanakul, P. Bee World 56 (3), pp. 119-121 . 1975 Varroa jacobsoni: A prospective pest of honeybees in many parts of the world Akratanakul, P., Burgett, M.