Population structure, recruitment, and succession of the brown alga, Padina boryana Thivy (Dictyotales, Heterokontophyta), at an exposed shore of Sirinart National Park and a sheltered area of Tang Khen Bay, Phuket Province, Thailand

The brown algal genus, Padina, has a worldwide distribution in tropical and subtropical climate zones. Padina individuals are common and sometimes dominant in both the intertidal and shallow subtidal regions associated with coral reefs. We investigated the population structure and recruitment of two populations of Padina boryana at an exposed shore in Sirinart National Park (SNP) and a sheltered shore of Tang Khen Bay (TKB), Phuket Province, Thailand. From September 2005 to August 2006, the number of released spores and the height and radius of fronds were measured monthly. New recruits were recorded and monitored on manipulated permanent plots 0.25 m². The experiment was carried out monthly over a year. We found Padina recruits 1 month after the plots were cleared at both sites. There was a significant difference in percentage cover by new individuals between the two locations (P < 0.05) and also at the shore levels within the sites. At SNP, the highest recruitment was found in the uppermost zone, while at TKB high recruitment occurred at all shore levels except at 80-100 m from the shore. The factors influencing recruitment of P. boryana include wave motion, competition with other earlier successional species and sediment. The high availability of reproductive spores throughout the year, the successful recruitment and the Dictyerpa stage promote the successful establishment of Padina populations.     

Diversity of Anopheles species and trophic behavior of putative malaria vectors in two malaria endemic areas of northwestern Thailand

We determined the species diversity, blood‐feeding behavior, and host preference of Anopheles mosquitoes in two malaria endemic areas of Tak (Mae Sot District) and Mae Hong Son (Sop Moei District) Provinces, located along the Thai border with Myanmar, during a consecutive two‐year period. Anopheline mosquitoes were collected using indoor and outdoor human‐landing captures and outdoor cow‐baited collections. Mosquitoes were initially identified using morphological characters, followed by the appropriate multiplex AS‐PCR assay for the identification of sibling species within Anopheles (Cellia) complexes and groups present. Real‐time PCR was performed for parasite‐specific detection in mosquitoes (Plasmodium spp. and Wuchereria bancrofti). A total of 7,129 Anopheles females were captured, 3,939 from Mae Sot and 3,190 from Sop Moei, with 58.6% and 37% of all anophelines identified as An. minimus, respectively. All three malaria vector complexes were detected in both areas. One species within the Minimus Complex (An. minimus) was present along with two related species in the Funestus Group, (An. aconitus, An. varuna), two species within the Dirus Complex (An. dirus, An. baimaii), and four species within the Maculatus Group (An. maculatus, An. sawadwongporni, An. pseudowillmori, and An. dravidicus). The trophic behavior of An. minimus, An. dirus, An. baimaii, An. maculatus, and An. sawadwongporni are described herein. The highest An. minimus densities were detected from February through April of both years. One specimen of An. minimus from Mae Sot was found positive for Plasmodium vivax.     

Morphological characteristics in relation to diet in five coexisting Thai fish species

Morphological characteristics and intestinal content were analysed for five species of coexisting freshwater fishes in Thailand: Rasbora caudimaculata , Schistura desmotes , Dermogenys pusillus , Xenentodon cancila and Monopterus albus (all found in riffle habitats in Thai streams). Rasbora caudimaculata , S. desmotes and D. pusillus fed predominantly on ephemeropterans, hymenopterans and dipterans, X. cancila fed predominantly on fishes, and larger aquatic invertebrates such as Odonata, and M. albus fed on detritus as well as invertebrate prey such as crustaceans and Odonata. Intestine length, mouth height, mouth width, eye position and mouth orientation varied among all five species. Canonical analysis of discriminance of mouth height, width and intestine length showed a clear dispersion of species, which was supported by intestine content. Evolutionary processes leading to the present differences in morphological characters resulted in each of the five species consuming a different portion of the available resource base, thereby facilitating coexistence.     

Ovitrap surveys of dengue vector mosquitoes in Chiang Mai, northern Thailand: seasonal shifts in relative abundance of Aedes albopictus and Ae. aegypti

Aedes aegypti (L.) and Aedes albopictus (Skuse) were surveyed using ovitraps in residential areas in Chiang Mai, northern Thailand. Egg populations (both species inclusive) remained low in the dry season, but increased/decreased exponentially during the first/latter half of the rainy season, respectively. This seasonal pattern was similar to the seasonal distribution of dengue haemorrhagic fever cases in the area. During the dry season (November-March) Ae.aegypti was dominant in urban and indoor ovitraps. With onset of the rainy season in April, relative abundance of Ae.albopictus increased in rural and outdoor ovitraps. Ae.albopictus displaced Ae.aegypti in the latter half of the rainy season in the rural area. Possible mechanisms to account for this seasonal decline of Ae.aegypti and reciprocal fluctuations in relative abundance of Ae.albopictus are discussed in relation to food availability for larvae in container habitats.     

Native root-nodule bacteria of traditional soybean-growing areas of northern Thailand

Over 1500 root-nodule bacteria were isolated from a range of uninoculated soybeans, and one cowpea, trap-hosts, sown in 1985 into traditional soybean-growing areas of soybean-growing areas of northern Thailand. Most isolates were slow-growing Bradyrhizobium japonicum. Using a modified bottle-jar technique, 586 of the isolates were tested with a range of soybean hosts and one cowpea host. The results indicated:

Lecane segersi n.sp. (Rotifera, Lecanidae) from Thailand

Lecane segersi n.sp. collected from a swamp in Udornthani province, northeastern part of Thailand, is described and figured. It is closely related to the common, warm-stenotherm Lecane papuana (Murray), but distinguished by the presence of inwardly directed antero-lateral spines.     

Ostrincola humesi sp. nov., a myicolid copepod (Poecilostomatoida) parasitic in rock oysters cultured in the Gulf of Thailand

A new species of poecilostomatoid copepod, Ostrincola humesi (Myicolidae), is described, based on specimens collected from the mantle cavity of the rock oyster, Saccostrea cucullata (Born), cultured in the Gulf of Thailand. A close comparison was made between the new species and Ostrincola koe Tanaka with which the new species was previously confused. A key to the nine species of Ostrincola is provided.     

Life cycle of Porphyra vietnamensis Tanaka & Pham-Hoang Ho from Thailand

Porphyra vietnamensis Tanaka & Pham-Hoang Ho is a tropical species of high potential for farming. Studies of the life cycle have been conducted for many years but have not been successful until recently. Mature thalli were collected from Songkhla, in the southern part of Thailand, and were used to obtain Conchocelis in the laboratory in Bangkok. Conchocelis in shells as well as free-floating filaments could be observed after one week of incubation at 25 °C, 25 salinity and 350–500 lux light intensity, and covered the culture shell surface within 2 months. Conchosporangia were formed after being incubated for 10 days at 30 °C, 20 salinity under light intensities of 350–500 lux with a photoperiod of 12 hours a day. Induction of conchospore release was achieved by lowering the temperature to 25 °C and the salinity to 10–15 and increasing the light intensity to 800–1000 lux. Liberated conchospores germinated into young thalli which became mature after 70 days.     

在中国壮族家系中发现的一例-α~T/-α~Q复合β~0β~0珠蛋白基因型

本文报道在我国广西隆林壮族中发现一个罕見的HbQ复合α,β地中海贫血家系。先证者女,18岁,贫血面容,肝脾肿大。化学结构分析确证本Hb变异体为HbQ Thailand[α74(EF3)Asp→His]。血红蛋白组成以及α和β珠蛋白基因分析结果表明,先证者的珠蛋白基因型为-α~Q/-α~T复合β°/β°(IVSI-1G→T/Codon17A→T);先证者父的基因型为-‘α~Q/-复合β~O/β~A(IVSI-1G→T/β~A);先证母的基因型为-α~T/αα复合β~O/β~A(Codon17A→T/β~A)。     

Hatching plasticity in a Southeast Asian tree frog mitigates submergence-induced mortality

Environmentally cued hatching has been well-documented in amphibians in response to a wide range of abiotic and biotic factors. The hatching of terrestrial amphibian eggs in response to flooding may be basal within the group, but amphibian lineages in tropical Asia and sub-Saharan Africa have not received as much attention as their Neotropical counterparts. We investigated submergence-induced hatching in Feihyla hansenae, a Rhacophorid tree frog with terrestrial eggs. We quantified natural rates of clutch submergence at our study site in Thailand. Using submergence experiments, we found that embryos are capable of hatching early to escape flooding, and that failure to hatch results in mortality. Among the embryos that were able to hatch early, only the earliest, youngest hatchlings experienced a trade-off in body size that persisted for 6 days, while later, older hatchlings were not significantly smaller than spontaneous hatchlings under control conditions. By incorporating our natural and experimental data into Monte Carlo methods to simulate and compare survival probabilities with and without hatching plasticity, we found an overall 3.1% increase in submergence survival due to hatching plasticity. Our findings support the idea that flooding-induced hatching is widespread across amphibians with terrestrial eggs and highlight the importance of researching understudied tropical regions. As climate change is projected to affect rainfall patterns, the ability of embryos to escape abiotic egg-stage threats may be an indicator of species' ability to flexibly navigate a changing environment.