Boonsatien Boonsoong

An implementation plan for using biological indicators to improve assessment of water quality in Thailand.

Most national standards for assessment of water quality include physical and chemical indicators relevant to specific pollutants and stressors. However, biological communities reflect not only current conditions of aquatic resources but also change in conditions over time and impacts from multiple stressors. Assessing the health of the aquatic community (that is, bioassessments) has proven to be critical in protecting and maintaining healthy surface waters under the mandates of regulatory frameworks, such as the Clean Water Act in the USA and the Water Framework Directive of the European Union. Whereas, in Thailand water standards, bioassessment is lacking in favor of chemical criteria, only coliform bacteria measurement can be considered a surrogate biological parameter. Our paper argues that incorporating bioassessment will improve water resource condition evaluations and recommends the use of the benthic macroinvertebrate assemblage as a bioassessment framework in Thailand. We discuss the implementation of a bioassessment program that consists of two major components, (a) a scientifically valid technical approach and (b) consideration of technical resources for a cost-effective program. The technical design comprises (1) classification of streams into similar groupings, (2) design of a biological survey, (3) a well-documented sampling protocol, (4) calibration of biological metrics for data analysis, (5) development of criteria for determination of ecological condition, and (6) communication of the results to citizens and policymakers. A cost-effective way to develop a bioassessment program that will improve Thailand’s ability to measure water quality and to make good decisions to attain healthy quality status is to establish partnerships by coordinating efforts and sharing data and technology with adjacent regional environmental offices or provinces. This collaboration would be fostered through a long-term national water resources management strategy and clear definition of goals and desired outcomes that are critical components of the overall National Plan for Ecological Health.

Heptageniidae (Insecta, Ephemeroptera) of Thailand

Abstract Nine genera and twenty-two species of heptageniid mayflies from Thailand are defined in this present work as well as one suggested further subgenus, Compsoneuria (Siamoneuria) kovaci (species “incertae sedis”) including some particular characters. Taxonomic remarks, diagnoses, line drawings of key characters, distribution, habitat and biological data, and a larval key to the genera and species are provided. The chorionic eggs of eight genera and eight species were observed and shown using a scanning electron microscope.

Effects of the botanical insecticide thymol on biology of a braconid, Cotesia plutellae (Kurdjumov), parasitizing the diamondback moth, Plutella xylostella L.

Terpenes and biogenically related phenols commonly found in plant essential oils are known to be toxic to insect pests. Accordingly thymol was tested for acute toxicity via topical application to diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) and its parasitoid, Cotesia plutellae (Kurdjunov) (Hymenoptera: Braconidae under laboratory conditions. Topical application to adult female parasitoids versus second instars of P. xylostella showed that thymol was about 62 times less toxic to the parasitoid than to the host larvae with 24 h LD50 of 0.052 and 0.0008M, respectively. Although thymol was less toxic to the parasitoid, some biological parameters of the progeny at sublethal doses of surviving parasitoids were impaired such as rate of emergence and development time of larvae and pupae. The impact on detoxification enzymes was also studied and there was no significant induction in cytochrome P450 and carboxylesterase activities in both treated male and female wasps. Results obtained suggest that parasitoid is able to withstand the impact of thymol significantly.

New records of Isonychia formosana, Prosopistoma annamense and Prosopistoma sinense (Ephemeroptera) from Thailand

We describe the distribution and habitats of three new recorded mayfly species from Thailand: Isonychia formosana (Isonychidae), Prosopistoma annamense (Prosopistomatidae) and P. sinense. This is a new record from Thailand, reporting these species for the first time. A key to known larvae of Thai Prosopistoma species is provided.

A new species of Platybaetis Müller-Liebenau, 1980 (Ephemeroptera: Baetidae) from Thailand, with description of the imago of Platybaetis bishopi Müller-Liebenau, 1980

Platybaetis bishopi Müller-Liebenau, 1980 was originally described from Malaysia only at the larval stage. We provide the first description of the imaginal stage of P. bishopi based on materials from Thailand. The imago of this species can be separated from the known species by coloration of abdominal terga and coloration of wings. A new species, Platybaetis nayokensis sp. nov., is described based on male and female imagos and larvae from Thailand. The larva of this species is mainly distinguished by medium acute spines on the posterior margin of the abdominal terga and two apical setae on the glossa, which seem to be shorter than in other species. The imago can be separated by the abdominal color pattern. The larva of this genus is adapted to live on wet rocks projecting out of water; it prefers large stones near small waterfalls or areas between two large rocks in running water.

Description of two final stadium Onychogomphus larvae from Thailand (Odonata: Gomphidae).

The final stadium larvae of Onychogomphus castor Lieftinck and O. duaricus Fraser are described and illustrated for the first time based on reared specimens from Thailand. The taxonomic characteristics of the larvae of the genus Onychogomphus are discussed and summarized. The larva of O. castor differs from other Southeast Asian species in having distinct mid-dorsal spines on S2-9, divergent wing pads reaching S5, and lateral spines on S6-9. The larva of O. duaricus has a weakly swollen third antennal segment, with short blunt mid-dorsal spines on S2-9, divergent wing sheaths reaching the middle of S4, and lateral spines present on S7-9.

Description of the final instar larva of Pseudagrion pruinosum (Burmeister, 1839) (Odonata: Coenagrionidae) from Thailand

Herein the final instar larva of Pseudagrion pruinosum (Burmeister, 1839) is described and illustrated for the first time, based on reared specimens from Thailand. When compared with the other known Pseudagrion larvae, P. pruinosum is distinguished by three setae on the labial palp, five teeth on the truncate, denticulate lobe on the distal marginal end of the labial palp, one premental seta and a row of three minute setae on each side of the midline, as well as shape and tracheation of caudal gills.

The nymph of Gilliesia Peters & Edmunds, 1970 (Ephemeroptera: Leptophlebiidae), with description of a new species from Thailand.

The new species Gilliesia ratchaburiensis sp. nov. is described based on male and female imagos (some of them reared from nymphal stages), nymphs and eggs collected in western Thailand. The nymph of Gilliesia, which is described for the first time, has bifid gills, a dense patch of setae on the ventral side of the glossae, no posterolateral spines on abdominal segment VIII, maxillary palpi 3-segmented and very reduced maxillary canines. Compared to congeners, the male imagos of the new species have penis lobes more straight and with the apical portion bent laterally but not ventrally, and female abdominal sternum 9 with a U-shaped, deep, median cleft. Phylogenetically, Gilliesia seems to be more similar to Dipterophlebiodes than to Habrophlebiodes and other Leptophlebiinae. The present finding in Thailand expands the distribution of Gilliesia in tropical Southeast Asia.

A new species of Compsoneuriella Ulmer, 1939 (Ephemeroptera: Heptageniidae) from Thailand

A new species of Compsoneuriella Ulmer, 1939 is described based on male and female imagos, nymphs and eggs from Ratchaburi province, western Thailand. Compsoneuriella braaschi sp. nov. is closely related to C. thienemanni Ulmer, 1939, from Java and Sumatra, but differs in the larval stage by the maxilla bearing only 8-9 comb-shaped setae on the crown, two strong medial setae on the glossa, gills V-VII apically acutely pointed and the posterior margin of the abdominal terga without distinct rows of submarginal microdenticles. In the male imaginal stage, the new species differs from C. thienemanni by having more reduced spines on the penis lobes and the titillators being directed outwards and strongly pointed at their apices.

Description of the last stadium larva and female of Microgomphus thailandica Asahina, 1981 (Odonata: Gomphidae).

The last stadium larva of Microgomphus thailandica is described, illustrated and compared with the larvae of congeneric species based on reared specimens collected from the Phachi headwater stream, Ratchaburi province, Thailand. The female adult of this species is described for the first time from a reared specimen from the same locality.