Ground dwelling pygmy grasshoppers (Orthoptera: Tetrigidae) in Southeast Asian tropical freshwater swamp forest prefer wet microhabitats

Abstract

Tetrigidae are an ancient group of grasshoppers and, similar to many other insects, have associations and preferences for specific microhabitats and habitats. The ecology of pygmy grasshoppers in Southeast Asia is generally under studied, especially in threatened habitats such as freshwater swamp forests. A study in Nee Soon Swamp forest, Singapore, was conducted to investigate association of limno-terrestrial pygmy grasshoppers with waterbodies and microhabitat. Specifically, we looked at the abundance and species assemblage of all pygmy grasshoppers. We correlated the abundance with major gradients of variation summarizing substrate and vegetation types along belt transects where sampling was performed. We found that pygmy grasshoppers in general are associated with wetter microhabitat conditions rather than the main streams in the swamp forest (i.e., water bodies). This is despite differences in microhabitat conditions of belt transects nearer to and further away from the main streams. We also found that pygmy grasshopper abundance is associated with the wetness of dicot leaf litter. We inferred that the abundance of food resources and suitability for egg development may explain their preference for wet microhabitats. We also found that the same patterns applied for adults and juveniles, suggesting that there is no demographic difference or ontogenetic shift in microhabitat association. Lastly, the adult assemblage can also be correlated to microhabitats. Based on our findings, we propose that pygmy grasshoppers can also be suitable bioindicators for the freshwater swamp forest, owing to their sensitivity to microhabitat conditions.

Soundscape of urban-tolerant crickets (Orthoptera: Gryllidae, Trigonidiidae) in a tropical Southeast Asia city, Singapore

“…Research on the orthopterans from Singapore has caught up in the past decade, particularly on species diversity (e.g., Tan 2010Tan , 2012Tan , 2013, new species discovery (e.g., Gorochov and Tan 2012;Tan and Robillard 2014), ecology (e.g., Tan and Tan 2017;Tan et al 2017a) and natural history (e.g., Tan 2011;Tan et al 2017b;Fung et al 2018). As many as 200 species of orthopterans can be found in the forest remnants of Singapore but studies incorporating bioacoustics data are relatively few (but see Gorochov and Tan 2012;Tan and Robillard 2014) and concerted investigation on the orthopteran calls from Singapore is scanty (but see Tan et al 2018Tan et al , 2019.…”

Mitochondrial genomes of eight Scelimeninae species (Orthoptera) and their phylogenetic implications within Tetrigoidea

“…Members of this subfamily generally inhabit moist environments, including wetlands and forest streams, and feed on lichens, mosses, and humus ( Muhammad et al, 2018 ; Wei, Xin & Deng, 2018 ). They are regarded as important ecological indicators for the freshwater swamp forest because of their sensitivity to their microhabitat ( Tan, Yeo & Hwang, 2017 ; Chen et al, 2018 ). However, the phylogenetic relationships between different genera of Scelimeninae are not well understood, nor is the taxonomic status of Scelimeninae within Tetrigidae ( Deng, 2016 ; Adžić et al, 2020 ).…”

A new species and morphometric analysis of Cladonotella (Tetrigidae: Cladonotinae)

“…Limestone on the surface was also covered with wet mosses. This suggests that the pygmy grasshoppers probably prefer wet microhabitats, as is the case for other Southeast Asian tetrigids (Tan et al 2017a). The forest on the hill (background of Fig.…”

“…Tetrigidae, commonly known as the pygmy grasshoppers, is a speciose group of orthopterans typically characterized by a pronotum that extends to cover part or all of the abdomen (Hancock 1907a, Günther 1935, Blackith 1992. The tetrigids are distributed globally and previously studied species are known to have a specialized ecology (Tan et al 2017a). However, classification and taxonomy of many groups of this family are still problematic, despite recent major revisionary works (e.g.…”