Biodiversity, Culture, and Ecology of Trichoptera from Phum Duang tributaries, Surat Thani Province, Southern Thailand

Abstract

Khao Sok, Khlong Phanom, Kaengkrung National parks, and Khlong Saeng Wildlife Sanctuary are among the protected areas in Surat Thani Province. They are located on the western side of Surat Thani city. This area is part of the lowlands of the Lower Phuket Mountain range, an extension of the Tenasserim Hills of the Indo-Malayan Mountain system, and serves as the main source of water supply to the streams of Khlong Sok, Khlong Phanom, Khlong Saeng, and Khlong Yang. These tributaries drain most of the eastern side of the Phuket Mountain range, they converged to form Phum Duang before joining the Tapi river which empties into the Thai gulf. To investigate the occurrence, distribution, and abundance of Trichoptera fauna, and to observe the life cycle and their ecological roles in this area, a survey was carried out in MarchDecember 2019. The survey was conducted along Khlong Sok, Khlong Phanom, Khlong Saeng, and Khlong Yan tributaries. The result showed that eighteen families (18), fifty-one (51) genera, and two hundred and one (201) instant species were found. Families Leptoceridae, Hydropsychidae, Philopotamidae, and Ecnomidae were the most diverse and abundant and constituted more than sixty percent (60%) of the total population of the insects observed. During the research, a new species of Agapetus kaengkrungensis belonging to the Family Glossosomatidae was described and added knowledge to science. Three new records were also found Polymorphanisus scutellatus BANKS 1939* Cheumatopsyche opposita BANKS 1931* Cheumatopsyche contexta ULMER 1951*. The relationship of water quality parameters recorded during the survey was analyzed using Pearson’s Correlation method, the result showed that some species displayed both positive and negative responses to some water environmental variables. The life cycle of the Macrostemum floridum of the Hydropsychidae family, one of the common and dominant species in the survey was studied. The larval collection was from February to July 2021, a total of one hundred and twenty-five (125) larvae were collected. Identification and morphological description of the final instar were made. The larva has five distinct instar developmental stages (I-V). A graphical representation of the five instars was also produced to further describe the progressive distribution of the larvae from the first to the final instars. The study included their importance as sources of food for fish as well as their ecological roles in processing organic matter and energy translocation. Further observations extended to the food and feeding habits of M. floridum larvae which revealed that its major food resources consumed were blue-green algae, green algae, and diatoms.