An account on some katydids (Orthoptera: Tettigonioidea) from Panti Forest Reserve in Johor, Peninsular Malaysia.

Recent collection in Panti Forest Reserve in Johor, Peninsular Malaysia offered us the opportunity to better understand the species in southern Malay Peninsula. Two new species and one new genus of Meconematini are described here: Cercoteratura reflexa sp. n. and Platycercotura caricauda gen. et sp. n. We present new locality records for Peracca macritchiensis Tan & Ingrisch, 2014, Viriacca viridis Ingrisch, 1998; Lipotactes (Dialipotactes) maculatus Hebard, 1922; Asiophlugis rete Gorochov, 1998; and Arnobia pilipes tropica Gorochov, 1998, all of which were previously recorded in Pahang (Peninsular Malaysia) and Singapore, suggest that the distribution of these species is continuous between Pahang and Singapore. New locality record for Asiophlugis temasek temasek Gorochov & Tan, 2011, previously known only from Singapore, indicates that this subspecies is no longer endemic to Singapore.

A taxonomic review of Odontogryllodes Chopard, 1969 (Gryllidae: Landrevinae).

The taxonomy of the crickets from the genus Odontogryllodes Chopard, 1969 is reviewed. Two species new to science are described here, one from Peninsular Malaysia (part of Malay Peninsula) and another from East Malaysia (part of Borneo): Odontogryllodes undatus Tan, Muhammad & Abdullah sp. nov. from Panti Forest Reserve and Odontogryllodes magnus Tan, Japir & Chung sp. nov. from Tenompok Forest Reserve, respectively. We also present an updated key to the species of Odontogryllodes. In total, nine species are currently known.

New species of Itara (Orthoptera: Grylloidea: Itarinae) and descriptions of calling songs from Mindanao and Sabah.

A new species of Itara (Phormincter) is described from Mindanao in the Philippines: Itara (Phormincter) mindanao Tan, Grumo, Gono & Bahoy, sp. nov. This represents the first record of this subgenus in the Philippines, having previously known only from Borneo, Java, Malay Peninsula and Sumatra; as well as only the second species of Itara known from the Philippines and the first from Mindanao Island. The male calling song of the holotype was also recorded and is described here. Additionally, the male calling song of another congener, Itara (Singitara) singularis Gorochov, 1997 from Sabah, is described here. A new species of Itara (Bornitara) is also described from Sabah in Borneo: Itara (Bornitara) tenompok Tan, Japir & Chung, sp. nov.

An account on some katydids of the tribes Agraeciini (Conocephalinae) and Meconematini (Meconematinae) from the highlands of western Sabah.

Based on recent field sampling in the highlands of western Sabah, a new species of Depressacca Ingrisch, 1998 (Conocephalinae: Agraeciini) is described from Tenompok, Depressacca macrolima sp. nov., that can be easily distinguish from two other known congeners by the presence of numerous large and falcate spines on the legs numerous large and falcate spines on its legs. Based on the new material, we also document here the live images and/or new locality records for other katydids of the tribes Agraeciini and Meconematini: Bispinolakis longicauda Ingrisch, 1998, Palaeoagraecia philippina (Karny, 1926) and Salomona borneensis Willemse, 1959; Alloteratura (Meconemopsis) longa Gorochov, 2008, Borneratura kinabaluana (Bey-Bienko, 1971) and Rhinoteratura pulchra Gorochov, 2008.

New species of the elusive crickets from the genus Pendleburyella Chopard, 1969 (Gryllidae, Pentacentrinae) from Sabah, Borneo.

Only one species of Pendleburyella Chopard, 1969 (Gryllidae, Pentacentrinae) was previously known to occur in Borneo: Pendleburyella eirmosa Tan, Muhammad & Wahab, 2023 from Brunei Darussalam. Here, two additional new species of crickets from the genus Pendleburyella are described from the highlands of Sabah, Borneo: Pendleburyella eremita sp. nov. from Bukit Hampuan and Pendleburyella nimba sp. nov. from Mount Trus Madi. In total, six species of Pendleburyella are currently known, three from Borneo and three from Malay Peninsula. It is likely that many more species are awaiting discovery owing to its cryptic morphology and elusive nature.

Pygmy grasshoppers (Orthoptera: Tetrigidae) from Bach Mã National Park, central Vietnam.

A list of 10 species from three subfamilies of Tetrigidae from Bach Mã National Park in the province of Thua Thiên-Hue, Vietnam is presented here. Eight of which are new for the national park. Among these, two new species are described: Miriatroides luna Tan & Storozhenko, sp. nov. and Rhopalina bachma Tan & Storozhenko, sp. nov. New synonymy is proposed: Systolederus cinereus Brunner von Wattenwyl, 1893 = Systolederus ridleyi Hancock, 1909, syn. nov. Three species are also recorded in Vietnam for the first time: Tegotettix bufocrocodil (Storozhenko & Dawwrueng, 2015) previously known from Thailand and Cambodia, Zhengitettix albitarsus Storozhenko, 2013 so far considered as endemic to Thailand, and Systolederus cinereus widely distributed in Southeast Asia.

The taxonomy and bioacoustics of the elusive crickets from the genus Pendleburyella Chopard, 1969 (Gryllidae: Pentacentrinae).

The taxonomy of poorly known crickets from the genus Pendleburyella Chopard, 1969 (Gryllidae, Pentacentrinae) is reviewed. The type specimens of described species were re-located and re-examined. Based on more recent collections, we describe two new species: Pendleburyella eirmosa sp. nov. and Pendleburyella pimela sp. nov., from Brunei Darussalam and Singapore respectively. The new material also allowed us to examine the male genitalia and describe the male calling song of the genus for the first time.

Notes on the Eneopterinae (Orthoptera, Grylloidea, Gryllidae) from eastern Sabah.

Based on material collected during recent fieldwork in eastern Sabah, the males of Nisitrus danum Robillard & Tan and Cardiodactylus variegatus Gorochov & Robillard are described for the first time, along with their calling songs. New locality records of N. danum, N. vittatus (Haan), Falcerminthus sandakan (Tan et al.), Cardiodactylus borneoe Robillard & Gorochov and C. variegatus are also presented. New material of Nisitrus species-N. danum and N. vittatus-allowed us to compare these syntopic species.

A new species of Asiophlugis (Orthoptera: Tettigoniidae: Phlugidini) from Misamis Oriental (Philippines, Mindanao).

A new species of Asiophlugis Gorochov, 1998 (Orthoptera, Tettigoniidae, Phlugidini) is described from southern Philippines, in Mindanao, Misamis Oriental, Gingoog City: Asiophlugis spatulata sp. nov. This new species is characterised by the long, slender and flattened male cercus, with a basal process spatulated at the apex, and with a tooth-like medial process produced along the inner margin; as well as the male tenth abdominal tergite with two long cylindrical latero-apical processes pointing dorsad and externally. This new species represents the second species of Asiophlugis to be recorded from the Philippines.

The circadian calling activity of a lebinthine cricket with high-frequency calls is unaffected by cicada choruses in the day.

Background: Many factors can influence circadian rhythms in animals. For acoustically communicating species, both abiotic cues (such as light and temperature) and biotic cues (such as the activity of other animals), can influence the timing of signalling activity. Here we compare the 24-h singing activity of the cricket Lebinthus luae in the laboratory and field to assess whether the presence of other singing insects influences circadian rhythm. Methods: Acoustic monitors were placed in four localities in Singapore and the number of L. luae calls were counted for 10 min of each hour. Individuals from the same localities were captured and recorded in the laboratory in silence but with similar abiotic conditions (temperature and light cycle) as they experience in the field, and the number of calls over 24 h was quantified. Results: The 24-h pattern of L. luae singing was not significantly different between laboratory and field recordings. Singing activity peaked in the morning, with a secondary peak in the afternoon and a smaller peak at night. In the field, L. luae sang in the same locations and at the same time as diurnally singing cicadas, suggesting that the sympatric cicada chorus did not affect the circadian rhythm of communication in this species. Acoustic niche partitioning could potentially explain the ability of this cricket to call alongside cicadas: L. luae sings at higher frequencies than sympatric cicadas, unlike nocturnally singing cricket species that overlap with cicadas in frequency.

Taxonomy and bioacoustics of little-known Grylloidea crickets (Orthoptera, Ensifera) from Mindanao, Philippines.

Orthopteran surveys were conducted recently on Mindanao Island of the Philippines. Four species new to science are described here: Mistshenkoana lunotan sp. nov., Mistshenkoana higaonon sp. nov. and Ectatoderus dubius sp. nov. from Misamis Oriental; and Phaloria (Phaloria) rotundata sp. nov. from Agusan del Sur. Based on new collected material, Madasumma fuscoirrorata Chopard, 1925, first described based on a single female from Mindanao, is transferred to Varitrella (Cantotrella) fuscoirrorata (Chopard, 1925) comb. nov. We also describe the male of this species for the first time. Madasumma zamboanga Otte, 2007, first described from Zamboanga del Norte (Mindanao), is also transferred to Mnesibulus (Amnesibulus) and redescribed: Mnesibulus (Amnesibulus) zamboanga (Otte, 2007) comb. nov. We also describe previously unknown calling songs of seven species: Falcerminthus parvus (Baroga-Barbecho & Robillard, 2020), Ajorama balatukanis Otte, 1988, Varitrella (Cantotrella) bakeri (Chopard, 1925), Varitrella (Cantotrella) fuscoirrorata (Chopard, 1925) comb. nov., Phaloria (Phaloria) rotundata sp. nov., Ornebius bioculatus Tan et al., 2019 and Ectatoderus dubius sp. nov.

A review of the genus Monseremus Ingrisch, 2018 (Orthoptera, Stenopelmatoidea, Gryllacrididae) from Borneo.

We review the taxonomy of the gryllacridids from a small genus Monseremus Ingrisch, 2018. Monseremus bellus (Tan Wahab, 2018) comb. nov., previously described from Brunei Darussalam before the description of Monseremus, is now added as a second known species in this genus. From a recent field trip, we also added new locality record for the type species Monseremus appendiculatus Ingrisch, 2018. First described from Mount Kinabalu in western Sabah, this species has now been reported also in Mount Silam in eastern Sabah. Males of the type species were also collected for the first time and are described here. Lastly, we provide a dichotomous key to separate these two species.

New taxa and notes on bark and bush crickets (Orthoptera, Grylloidea, Gryllidae, Landrevinae and Podoscirtinae) from Sabah.

From the eastern parts of Sabah, four new species of crickets are described, two of which are from the subfamily Landrevinae and two from the subfamily Podoscirtinae: Duolandrevus (Duolandrevus) nobilis sp. nov. and Odontogryllodes spinifer sp. nov.; and Brevimunda trilineata sp. nov. and Varitrella (Cantotrella) tabin sp. nov., respectively. We also describe the calling songs for three species: Duolandrevus (Bejorama) lambir Gorochov, 2017, Duolandrevus (Duolandrevus) nobilis sp. nov. and Varitrella (Cantotrella) tabin sp. nov. A new locality record (Sabah, Sepilok) for Duolandrevus (Bejorama) lambir Gorochov, 2017, previously known from western Borneo (Sarawak, Lambir Hill and Brunei Darussalam, Kuala Belalong), was also reported.

Phenotypic plasticity of acoustic traits in high-frequency lebinthine crickets (Orthoptera: Eneopterinae: Lebinthina).

Driven by natural and sexual selection, calling behaviours and call parameters can vary within and between individuals. Phenotypic plasticity can be influenced by environmental conditions (e.g., temperature), size, body condition, and age. Crickets have been classic model organisms for studying the evolution of acoustic communication, but previous studies have focused on field crickets, for which males call at a low frequency, while females exhibit phonotaxis. This study holistically investigated the plasticity of calling behaviours and call parameters across a temperature gradient in a species of lebinthine crickets and examined plasticity between and within individuals. These crickets exhibit a unique communication system, including males calling at a near-ultrasonic frequency while actively searching for females. Ten recording assays at different temperatures were done on males of different sizes and body conditions, half of the assays when the males first became adults and another half 1 month later. Size, body condition, and age group of male crickets, as well as the ambient temperature, had different effects on different calling behaviours (e.g., number of songs produced) and call parameters (e.g., call duration, trill syllable period), even when the acoustic traits were correlated. The crickets also exhibited acclimatisation to the experimental conditions in their calling behaviours and acoustic traits to repeated assays. We also found that calling behaviours were less repeatable than temporal call parameters (e.g., call duration, trill duration), which in turn, were less repeatable than the spectral call parameter (dominant frequency).

A new aboreal species of sword-tailed cricket (Orthoptera: Trigonidiidae: Trigonidiinae) from the mangrove in Singapore.

Sword-tailed crickets of the genus Amusurgus Brunner von Wattenwyl, 1893 (Orthoptera: Trigonidiidae: Trigonidiinae) from Southeast Asia is still poorly known and its taxonomy requires a revision. Many species are still awaiting discovery and formal description. Based on newly-acquired materials from the mangrove in Singapore, a new species of Amusurgus is described: Amusurgus (Amusurgus) caerulus sp. nov. This discovery also demonstrates that even in a small country like Singapore, we still do not have a comprehensive understanding of its orthopteran diversity.

Contribution to the taxonomy of Uvarovia (Orthoptera: Chorotypidae: Mnesicleinae) from Borneo and Malay Peninsula.

Mnesicleinae is a little-known subfamily of Chorotypidae and consists of 19 genera distributed throughout the Malay Archipelago, including Uvarovia Bolvar, 1930. For many species from this subfamily, nearly nothing is known after their original descriptions. Based on new materials from recent surveys, we were able to examine specimens from two species: Uvarovia longipennis Bolvar, 1930 from Malay Peninsula (also type species for genus) and Uvarovia gracilipes Bolvar, 1931 from Borneo. Only female specimens were known for the two species. Here, we describe for the first time males specimens of Uvarovia longipennis and Uvarovia gracilipes. We also present an updated key to species of Uvarovia and a key to genera of Mnesicleinae from Borneo and Malay Peninsula.

Spiky pygmy devils: revision of the genus Discotettix (Orthoptera: Tetrigidae) and synonymy of Discotettiginae with Scelimeninae.

Spiky pygmy devils (Tetrigidae: Discotettiginae) are, because of the spiky pronotal projections and widened subapical antennal segments, among the most unique pygmy grasshoppers in Southeast (SE) Asia. The taxonomy of the group was unclear in the past, so this study brings a taxonomic and biographical review of the genus Discotettix Costa, 1864. New terminology of the pronotal projections is proposed for Scelimeninae. All valid species hitherto included in the genus are redescribed; a new genus is established for Discotettix shelfordi Hancock, 1907, Disconius Skejo, Pushkar et Tumbrinck gen. n., so a new combination is established for the species (Disconius shelfordi comb. n.). New synonymy is established: Discotettix selysi Bolívar, 1887 = Discotettix selangori Mahmood, Idris et Salmah, 2007 syn. n. Three new species are described and a key to Discotettix species is provided. The genus now includes seven species (1) Discotettix aruanus Skejo, Pushkar et Tumbrinck sp. n. from Aru; (2) D. belzebuth (Serville, 1838) from Borneo; (3) D. doriae Bolívar, 1898 stat. resurr. from the Mentawai islands; (4) D. kirscheyi Skejo, Pushkar, Tumbrinck et Tan sp. n. from Northeast (NE) Borneo; (5) D. scabridus (Stål, 1877) endemic to Mindanao and Samar; (6) D. selysi Bolívar, 1887 from Sumatra and peninsular Malaysia; (7) D. sumatrensis Skejo, Pushkar et Tumbrinck sp. n. endemic to southern Sumatra. Moreover, Discotettix is again subdivided into two subgenera: Mnesarchus Stål, 1877 stat. resurr. (D. scabridus) and nominotypical one (other species). Widened antennal segments are the only character common to all Discotettiginae genera, but this trait does not have great taxonomic importance, as it is homoplastic, meaning that it appeared in distant Tetrigidae groups independently. Discotettix is herewith transferred to the subfamily Scelimeninae and accordingly, the subfamily Discotettiginae Hancock, 1907 syn. n. becomes a junior synonym of the subfamily Scelimeninae Bolívar, 1887. The tribe Discotettigini stat. resurr., on the other hand, gathers corticolous genera of the Scelimeninae (Austrohancockia Günther, 1938, Bidentatettix Zheng, 1992, Disconius gen. n. Discotettix, Eufalconius Günther, 1938, Gibbotettix Zheng, 1992, Paragavialidium Zheng, 1994, Gavialidium Saussure, 1862, and Tegotettix Hancock, 1913), while the tribe Scelimenini becomes restricted to amphibious taxa. All taxa are described and amply depicted with both museum specimens and in situ photographs. An identification key is provided. The morphology and function of widened antennae in Discotettigini are discussed.

Taxonomy and bioacoustics of scaly crickets (Orthoptera, Mogoplistidae, Mogoplistinae) from Borneo and Singapore.

A species of scaly cricket is described here: Ornebius lupus sp. nov. from the mangrove forests in Singapore. Ornebius pullus Ingrisch, 2006 is recorded in eastern Sabah for the first time. The calling songs of Cycloptiloides bimaculatus Tan et al., 2021 and Ornebius pullus from Sabah are described. We also revise the diagnosis of Ectatoderus nigrofasciatus Tan et al., 2021 from Brunei Darussalam.

Taxonomy and bioacoustics of some katydids of the tribes Meconematini and Phisidini (Orthoptera, Tettigoniidae, Meconematinae) from eastern Sabah.

A new species of Meconematini is described from Tabin Wildlife Reserve in eastern Sabah: Cercoteratura repens sp. nov. This is the first report of the genus Cercoteratura in Sabah. Two species of Phisidini, Carliphisis acutipennis (Carl, 1908) and Neophisis (Indophisis) longipennis Jin, 1992, are reported in eastern Sabah for the first time. The calling song of Neophisis (Indophisis) longipennis with a near-complete ultrasonic spectrum is also described.