www.thaiagj.org Thai Journal of Agricultural Science 2008, 41(1-2): 11-18 Diversity of Soil-Litter Insects: Comparison of the Pselaphine Beetles (Coleoptera: Staphylinidae: Pselaphinae) and the Ground Ants (Hymenoptera: Formicidae) W. Sakchoowong1,*, W. Jaitrong2, K. Ogata3, S. Nomura4 and J. Chanpaisaeng5 1Forest Entomology and Microbiology Group, National Parks Wildlife and Plant Conservation Department, Bangkok 10900, Thailand 2National Science Museum, Klong 5 Klong Luang, Pathumthani, 12120, Thailand 3Institute of Tropical Agriculture, Kyushu University, Fukuoka 812-8581, Japan 4Division of Entomology, Department of Zoology, National Museum of Nature and Science Shinjuku, Tokyo 169-0073, Japan 5Department of Entomology, Faculty of Agriculture, Kasetsart University Bangkok 10900, Thailand *Corresponding author. Email: [email protected] Abstract Forest litter-inhabiting arthropods except ants are poorly understood because of their small sizes and cryptic habitats. However, they play an essential role in nutrient cycling and contribute valuable data to study of comparative biodiversity and conservation. Soil beetles such as Pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) are cosmopolitan, species-rich, and yet poorly studied, particularly in the tropics. While ants (Hymenoptera: Formicidae) are a large component of the arthropod community on ground in forest ecosystems. We sampled pselaphine beetles and ants in three types of primary forest and two types of disturbed forest habitat in eastern Thailand to assess the utility of pselaphine beetles and ants to determine if one group could be predicted the diversity of other. We compared species richness, abundance and diversity of ground ants and pselaphine beetles in each forest types using 1 m2 quadrat samples and extracted them with Tullgren funnels. A total of 1,867 pselaphine individuals representing 114 species in six supertribes and 44,135 individuals, 142 species in nine subfamilies of ants were collected in all habitats. Species richness, abundance, and Shannon diversity of pselaphine beetles and ants showed a significant response to habitat types as the same manner. Both pselaphine beetle and ant species, abundance and diversity were significantly lower with increasing habitat disturbance. Strong relationships pattern between the two groups were significantly correlated in species richness, number of individuals and Shannon’s diversity index (H’) except Pielou’s evenness index (J’). In this study, we found that the relationships of ants and pselaphine beetles could be predicted the change in species richness, abundance and diversity of each other in response to habitat types. Keywords: diversity pattern, pselaphine beetles, ants, soil and litter, Eastern forest of Thailand Introduction 1992; Schulze et al., 2004). However, litter-inhabiting insects are poorly studied groups because of their A number of studies on insect biodiversity have small size and complex habitats. Although, they been increasing in the tropical rainforests (Wilson, play an essential role in soil i.g. nutrient cycling, 12 W. Sakchoowong et al. Thai Journal of Agricultural Science bioturbation and contribute valuable data to studies 58.31 km2. Precipitation in KARN is blocked by of comparative biodiversity and conservation high mountain of KSD which acts as a natural (Coddington et al. 1997; Stork, 1988). Pselaphine fence, making the climate relatively drier than those beetles (Coleoptera: Staphylinidae: Pselaphinae) in KSD and KKK. The annual precipitation in are among the most species-rich forest litter- KARN and KSD are relatively different with 1,600 inhabiting group (Carlton, 1999) and they play an mm in KARN and 3,800 mm in KSD. In eastern important role in the soil ecosystem as predators of Thailand, dry season lasts from November to small invertebrates (Newton and Chandler, 1989). March and wet season lasts from May to October This subfamily is species-rich and cosmopolitan. (Thailand Meteorological Department, 2007). Pselaphine beetles might therefore be profitably Differences of local precipitation and the altitude of used as indicator species for identifying habitat eastern forest areas ranging from 100 to 1,675 m differences and lack of disturbance in old-growth produce three various forest types (Kasetsart forests (Newton and Chandler, 1989). University, 2007), mixed deciduous forest, moist While, the ground ants perform a wide range of evergreen forest and hill evergreen forest. In ecological function as predators, preys, or addition for considering of human interruption mutualists with plants or animals (Schultz and which might be effect to local diversity of McGlynn, 2000). They are relatively sensitive and pselaphine beetles, we chose two inferior forest responsive to changes of ecosystem in habitats both types: secondary mixed deciduous forest (SMDF) spatial and time and they have been using as indicator and teak plantation forest (TP) for our experiment. taxon to assess impacts of environmental change on The detailed descriptions of forest types are shown biodiversity (Agosti et al., 2000; HÖlldobler and as following: Wilson, 1990; Toda and Kitching, 1999). In general, any forest conversions to other land Primary mixed deciduous forest (PMDF) use types will have markedly negative impacts on PMDF was dominated by Lagerstroemia venusta, diversity of animals and plants. Most studies just Lagerstroemia cuspidata, Pterocarpus macrocarpus, quantified the impact on diversity of single group Suregada multiflorum and Syzygium pergamenta- (Chey et al., 1997; Stork et al., 2003; Watt et al., ceum. Mixed deciduous forest site was established 2002). Only few studies had been reported the at Lum Jang Wat sub-district in KARN (N 13° 16' impact of tropical forest modification on several 25'', E 101° 44' 44'', 155 m elevation). taxonomic groups (Lawton et al., 1998; Schulze et al., 2004), however, their studies showed that no Moist evergreen forest (MEF) strongly pronounced relationships of change in MEF site was established at Ban Thung Krang species richness among the different animal groups. sub-district (N 13° 01' 08'', E 102° 12' 46'', 329 m Because of the importance of our understanding elevation). The dominant tree species are Diptero- of diversity pattern relationship of insect groups, carpus alatus, Mallotus peltatus, Shorea guiso, Strom- we undertook studies on species richness and bosia javanica and Diospyros transitoria. abundance of the pselaphine beetles and the ground ants in natural habitat. The results are reported in Hill ever green forest (HEF) this paper. HEF site was established at Khao Prabad (N 12° 50' 14'', E 102° 10' 20'', 1,069 m elevation). The Materials and Methods most abundant tree species in HEF were Scaphium scaphigerum, Castanopsis piriformis, Archidendron Study Sites quocense and Hornstedtia glabra. The eastern forest complex of Thailand consists of two wildlife sanctuaries, Khao Ang Rue Nai Secondary mixed deciduous forest (SMDF) Wildlife Sanctuary (KARN) with total area 1,030 Thirty percent of the land area in the northern km2, Khao Soi Dao Wildlife Sanctuary (KSD) with part of KARN was disturbed by human settlements total area 744.58 km2 and one national park, Khao and agriculture in 1992. The Royal Forest Department Kitchakut National Park (KKK) with total area has since relocated the villages and restored these Vol. 41, No.1-2, 2008 Diversity of soil-litter insects 13 areas. The forest has been recovering for approximate- Sorting and Identification ly 15 years. In the time of sampling, most of the The samples were taken to the laboratory, areas once opened by agriculture and villages are pselaphine beetles and ants were separated and stored covered with vegetation, and some of these areas in 80% ethanol. Pselaphine specimens were identified are now approaching an advanced stage of to genus using the keys of S. Nomura (S. Nomura, secondary forest; trees are approximately 10-12 m unpublished identification guide on subfamilies apart with diameter of 8-15 cm. We sampled an Protopselaphinae and Pselaphinae of Asia [Staphyli- SMDF site at Phuthai sub-district (N 13° 24' 56'', E nidae: Protopselaphinae; Pselaphinae] 2006), which 101° 52' 53'', 101 m elevation). The most abundant adopts the taxonomic conventions of Newton and tree species were S. multiflorum, L. venusta, S. Thayer (1995) and Chandler (2001). After generic pergamentaceum and P. macrocarpus. identification, specimens were then identified to morpho-species based on the external appearance Teak plantation (Tectona grandis L.) (TP) of specimens–a technique commonly used as a TP (Tectona grandis L.) were established in the surrogate for species level identification in boundary on the western part of KSD from 1969 to biodiversity studies (Abbott et al., 2002). 1992 by the Soi Dao Seed Orchard Station under Ant specimens were identified to genus using the Royal Forest Department project (Soi Dao key of Bolton (1994) and Hashimoto and Rahman Forest Seed Orchard Station, 1992). The plantations (2003), and later to species and morpho-species level, covering 376 ha have been designated for research using the reference collection of Thailand National and economic plantation. All teak plantations are Science Museum (TNSM). Voucher specimens of connected forming one large monoculture habitat in pselaphine beetle were mounted, labeled, and the KSD region. The teak plantation site (N 12° 58' deposited in the Forest Insect Museum (FIM), 48'', E 102° 17' 49'', 202 m elevation) chosen for Department