& Herpeto gy lo lo gy o : h C it u n r r r Freitag, Entomol Ornithol Herpetol 2015, 4:4 e O n , t y R g e o l DOI: 10.4172/2161-0983.1000166 s o e a m r o c t h n E Entomology, Ornithology & Herpetology ISSN: 2161-0983 ResearchRapid Communication Article OpenOpen Access Access Clues to Aquatic Beetle Research in Southeast Asia: A Multitude of Ecological Niches, Microhabitats and Deduced Field Sampling Techniques Hendrik Freitag* Ateneo de Manila University, School of Science & Engineering, Department of Biology, Science Education Complex-A, Katipunan Ave., Loyola Heights, 1108 Quezon City, Philippines Abstract The basic ecological classification of Southeast Asian beetle families that are associated with aquatic habitats is reviewed. The microhabitat preferences of the taxa are examined on family level with generic examples. Suitable collection methods for quantitative and qualitative sampling are suggested which take into account the different ecological adaptation patterns and microhabitat preferences. Keywords: Coleoptera; Water beetle; Riparian beetle; Southeast Asia; Ecological Classification of Aquatic and Riparian Biodiversity survey; Ecological classification; Microhabitat preference; Coleoptera Collection method In most aquatic insect orders (Odonata, Ephemeroptera, Introduction Plecoptera, Trichoptera), all immature life stages live in water and emerge to the terrestrial habitats as adults. In contrast, various patterns Coleoptera represent the world’s largest taxonomic order in terms of water association in different stages of ontogenesis can be recognized of the number of species. Currently 360,000 – 400,000 described species in aquatic and riparian beetles. are known while more than 1.1 million species can be expected [1]. Less than 2% of them possess a distinct adaption to aquatic habitats, Except for maybe some stygobiontic Coleoptera species, probably based on estimates of total species numbers of the respective ecological all aquatic beetles leave the water temporarily at least for a short period groups by Jäch and Balke [2], plus a presumably similar magnitude of of time during their life (e.g., for pupation or, dispersal flight) [2]. paraquatic/riparian species that are dependent on aquatic habitats in a Nine ecological groups of water -associated beetles were defined by lesser extent. Both, aquatic and riparian taxa are in particular focus of Jäch [6] based on their life history and behaviour. this paper. Facultative water beetles get actively submerged or live neustic Southeast Asia is usually referred to the countries of Cambodia, in aquatic habitats for a limited period of time for certain activities East Timor, Indonesia, Laos, Malaysia, Myanmar, the Philippines, (e.g., foraging) during True Water Beetles are submerged in water, or Singapore, Thailand, and Vietnam. However, this paper refers only dwell at the water surface for the major part of their adult life. Except to the part that belongs to the Oriental Realm. Nevertheless, most for a few families the larvae are strictly aquatic. In Southeast Asia, information given will apply to adjacent areas too. The entire region True water beetles occur in the following families: Hydroscaphidae, is dominated by islands and characterized by a complex biogeographic Gyrinidae, Dytiscidae, Noteridae, Haliplidae, Epimetopidae, history [3]. This has led to an overwhelming rate of endemism and Hydraenidae, Hydrochidae, Spercheidae, Hydrophilidae, Elmidae, and thus to a species diversity for which several areas of the region are Dryopidae. Except for Hydrophilidae and Dryopidae, terrestrial taxa recognized as biodiversity hotspots [4]. are exceptional or absent in these families. One Oriental family of True Water Beetles, Torridincolidae (Myxophaga) has never been recorded The United Nations has proclaimed an International Decade from Southeast Asia, but their presence cannot be ruled out. for Action-‘Water for Life’ 2005-2015 with conservation priority for freshwater biodiversity. Nevertheless, threats to the freshwater False water beetles possess larvae that live submerged in water, biodiversity have not diminished and freshwater biodiversity has further while adults are predominantly terrestrial. These include Scirtidae, declined during the last decade. Dudgeon et al. [5] have identified five Psephenidae, Eulichadidae, Lampyridae (some Luciolinae), and categories of major threats for aquatic inland systems: overexploitation, Ptilodactylidae (Cladotominae). pollution, flow modification, destruction or degradation of habitat, and invasion by exotic species. These multiple stressors to the biodiversity are all relevant in a special extent to freshwater habitats of Southeast *Corresponding author: Hendrik Freitag, Ateneo de Manila University, School Asia and its aquatic/riparian beetle fauna. The distributional ranges of of Science & Engineering, Department of Biology, Science Education Complex-A, Katipunan Ave., Loyola Heights, 1108 Quezon City, Philippines, Tel/Fax: +63-2- many taxa are small due to the high degree of natural fragmentation 426-1034; E-mail: [email protected] on the one hand. The anthropogenic impact on inland waters in most Received August 31, 2015; Accepted September 15, 2015; Published September countries of the region is high and further increasing, on the other 28, 2015 hand. Citation: Freitag H (2015) Clues to Aquatic Beetle Research in Southeast Asia: Since taxonomic and ecological interest in aquatic/riparian beetles A Multitude of Ecological Niches, Microhabitats and Deduced Field Sampling Techniques. Entomol Ornithol Herpetol 4: 166. doi:10.4172/2161-0983.1000166 has risen in the last decades in Southeast Asia, this paper is aimed to foster further research by providing an overview of the ecological Copyright: © 2015 Freitag H. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted classification and the respective microhabitats colonized by aquatic use, distribution, and reproduction in any medium, provided the original author and and riparian beetles. source are credited. Entomol Ornithol Herpetol, an open access journal ISSN: 2161-0983 Volume 4 • Issue 4 • 1000166 Citation: Freitag H (2015) Clues to Aquatic Beetle Research in Southeast Asia: A Multitude of Ecological Niches, Microhabitats and Deduced Field Sampling Techniques. Entomol Ornithol Herpetol 4: 166. doi:10.4172/2161-0983.1000166 Page 2 of 6 The larval and/or adult stage. Southeast Asian representatives are common taxa of Southeast Asia. For a more detailed systematic and surely known in the family Nitidulidae (one or few Amphicrossinae), ecological review, the respective chapters of the Handbook of Zoology and Lampyridae (some Luciolinae). However, other species can [10] (second edition forthcoming) provide most helpful information be expected in Carabidae (some Chlaeniinae), Staphylinidae and primary references, same as the cataogues which are available for (some Omaliinae, Staphylininae and Steninae), Scarabaeidae (few the following families: Dytiscidae [11]; Elmidae [12]; Epimetopidae Dynastinae), and Monotomidae (some Rhizophaginae). [13]; Georissidae [13]; Haliplidae [14]; Hydraenidae [15]; Hydrochidae Shore Beetles, also commonly called riparian beetles, live in the [13]; Hydrophilidae [13]; Lamypridae [16]; Limnichidae [17]; limnic littoral zone during all developmental stages, but do usually Noteridae [18]; Spercheidae [13]. not enter the water voluntarily. Heteroceridae and Georissidae are Natural running waters, even torrential mountain streams, are typical Shore Beetles. However, numerous other families are known never entirely lotic systems. They are rather a repeated consecution of to have riparian representatives: e.g., Sphaeriusidae, Carabidae, turbulent water flow (riffle), laminar, non-turbulent flow (run), and Helophoridae, Hydrophilidae, Histeridae, Hydraenidae, Ptiliidae, calm zones (pool); which might be additionally interrupted by falls. Leiodidae, Staphylinidae, Scarabaeidae, Dryopidae, Limnichidae, Elateridae, Lampyridae, Phycosecidae, Monotomidae, Tenebrionidae, Waterfalls are only colonized by a few species (larvae of Salpingidae, Anthicidae. Psephenidae, imagines and larvae of Elmidae) due to the extreme Phytophilous water beetles live on or in submerged plants during at hydraulic stress. Such taxa can be found in crevices of the rock surfaces. least one developmental stage. Donacia Fabricius (Chrysomelidae) and Waterfall associated microhabitats such as sprayzones and hygropetric Bagous Germar (Curculionidae) occur in Southeast Asia. rocks (Figure 1) accommodate some Hydraenidae (Hydraena Kugelann, Limnebius Leach), Hydrophilidae (some Hydrophilinae, Sphaeridiinae), Parasitic Water Beetles are associated with animal hosts in aquatic Hydroscapha LeConte (Hydroscaphidae), and Limnichidae. habitats during at least one developmental stage. There are no records yet from the Southeast Asia. Riffle and run sections of creeks and rivers are typically occupied by Elmidae, Dyropidae, Psephenidae (larvae), as well as some Gyrinidae, True marine beetles do not exist [2]. The following three classifications Dytiscidae, Limnichidae, Scirtidae and a few specialized species of are used for beetles associated with maritime saltwater habitats: Hydraenidae, Hydrophilidae and Lampyridae (larvae). Most genera are Epilittoral beetles always inhabit the littoral zone above the high typically found only in particular microhabitats of the lotic zones, such water mark and the spray zone.