Preliminary study on the diversity of Orthoptera from Kuala Belalong Field Studies Centre, Brunei Darussalam, Borneo

The Orthoptera, comprising grasshoppers, crickets, and katydids, is diverse and species rich in tropical Southeast Asia, including the island of Borneo. However, not every part of Southeast Asia is equally well sampled and studied. This includes Brunei Darussalam, specifically at the Kuala Belalong Field Studies Centre (KBFSC) within the Ulu Temburong National Park. We present here an annotated and illustrated checklist of Orthoptera from the primary dipterocarp forest around Kuala Belalong based on three field trips in 2016 and 2017. We provide notes on their taxonomy (including how each species was identified) and natural history of species. In total, 72 species were recorded, representing eight of the 16 monophyletic orthopteran superfamilies. In total, 73.6% of all species recorded were singletons and doubletons, indicating that many species are probably rare. The collection led to the discovery of ten species new to science already published separately, with more expected to be described from pending material and confirmation. More species, including undescribed ones (at least four new species), are expected with continued sampling effort. Despite the 21 day-long surveying efforts from three trips around KBFSC, we believe that the species list provided here is non-exhaustive and only a preliminary one

The calling songs of some katydids (Orthoptera: Tettigonioidea) from the tropical forests of Southeast Asia

Katydids produce sound by stridulation of the tegmina for signalling and communication. Most katydids are known to sing at ultrasonic frequencies, as compared to crickets. This has drawn interest to investigate the biophysics of ultrasonic sound production and detection, evolution and ecology (including predator–prey interactions) of these katydids. However, most of these studies are based on species from the neotropics, whereas nearly nothing is known about the relatives from another hyper-diverse region, i.e., Southeast Asia. To address this, a concerted effort to document, record and describe the calling songs of Southeast Asian katydids, especially species which calls at ultrasonic frequencies, were conducted. A study spanning over two years (2018 to 2020) in Malay Peninsula (Singapore and Malaysia), Borneo (Brunei Darussalam and Sabah) and the Philippines revealed previously unknown calls of 24 katydid species from four subfamilies. The calling songs of Southeast Asian katydid species are highly diversified in both the time and frequency domains. Call structure can range from isolated syllables (e.g., Holochlora), continuous trills (e.g., Axylus philippinus) to short pulse-trains (e.g., Euanisous teuthroides) and complex echemes (e.g., Conocephalus spp.). 87.5 % of species have ultrasonic peak frequencies and 12.5 % can be considered extreme ultrasonic callers (peak frequency >40 kHz). The call spectrum ranges from tonal (e.g., spectral entropy = 6.8 in Casigneta sp. 2) to resonant (entropy = 8.8 in Conocephalus cognatus). Of the 24 species whose calls are described here, we also imaged and described the sound-producing structures of 18 species. This study provides a preliminary overview of the acoustic diversity of katydids in Southeast Asia and the authors hope to inspire further investigation into the bioacoustics of little-known katydids from Southeast Asia. Amassing a database of calling songs and sound-producing organs from different species can be important to address the taxonomy impediment while advancing our knowledge about the bioacoustics of Southeast Asian katydids

A new species of Tapiena (Orthoptera: Tettigonioidea: Phaneropterinae) from Brunei Darussalam (Borneo, Southeast Asia)

Tan, Ming Kai, Wahab, Rodzay Bin Haji Abdul (2018): A new species of Tapiena (Orthoptera: Tettigonioidea: Phaneropterinae) from Brunei Darussalam (Borneo, Southeast Asia). Zootaxa 4413 (1): 193-196, DOI: https://doi.org/10.11646/zootaxa.4413.1.

New taxa and notes on palm and false-leaf katydids (Orthoptera: Tettigoniidae: Sexavaini; Pseudophyllinae) from Brunei Darussalam Running title: Sexavaini and Pseudophyllinae from Brunei

As many as 72 species were documented when sampling was conducted in Kuala Belalong in Brunei Darussalam between 2016 and 2017 but this remains non-exhaustive and orthopteran species are still awaiting discovery. Based on new material collected in 2019, two new species of katydids are described here: Segestes nostosalgos sp. n. and Sathrophylliopsis mentham sp. n. These two discoveries are of particular interest: Segestes nostosalgos sp. n. represents the first record of the tribe Sexavaini in Borneo; Sathrophylliopsis mentham sp. n. is drastically different from congeners by the lack of dense fine long hairs around the body

A short taxonomic note on the katydids from the genus Cercoteratura Gorochov, 2019 (Orthoptera: Tettigoniidae: Meconematinae), with a key to species

Tan, Ming Kai, Wahab, Rodzay Bin Haji Abdul (2020): A short taxonomic note on the katydids from the genus Cercoteratura Gorochov, 2019 (Orthoptera: Tettigoniidae: Meconematinae), with a key to species. Zootaxa 4750 (4): 591-595, DOI: https://doi.org/10.11646/zootaxa.4750.4.1

New taxa and notes of katydids from the tribe Meconematini (Orthoptera: Meconematinae) from Brunei Darussalam (Part 2)

Tan, Ming Kai, Wahab, Rodzay Bin Haji Abdul (2018): New taxa and notes of katydids from the tribe Meconematini (Orthoptera: Meconematinae) from Brunei Darussalam (Part 2). Zootaxa 4407 (4): 582-590, DOI: https://doi.org/10.11646/zootaxa.4407.4.1

Notes on the taxonomy of poorly known Gryllacrididae (Stenopelmatoidea) from Brunei Darussalam, Borneo

Tan, Ming Kai, Wahab, Rodzay Bin Haji Abdul (2018): Notes on the taxonomy of poorly known Gryllacrididae (Stenopelmatoidea) from Brunei Darussalam, Borneo. Zootaxa 4462 (4): 579-591, DOI: https://doi.org/10.11646/zootaxa.4462.4.