Two new genera and species of the Gigantometopini (Hemiptera, Heteroptera, Miridae, Isometopinae) from Borneo with remarks on the distribution of the tribe

Two new genera, each represented by a single new species, Planicapitus luteus Taszakowski, Kim & Herczek, gen. et sp. nov. and Bruneimetopus simulans Taszakowski, Kim & Herczek, gen. et sp. nov., are described from Borneo. Detailed photographs of male habitus and genital structures are presented. The checklist with distributional records for all known taxa of Gigantometopini is also provided

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

Benthic community structure and ecosystem functions in above- and below-waterfall pools in Borneo

Waterfalls are geomorphic features that often partition streams into discrete zones. Our study examined aquatic communities, litter decomposition and periphyton growth rates for above- and below-waterfall pools in Ulu Temburong National Park, Brunei. We observed higher fish densities in below-waterfall pools (0.24 fish m−2 vs. 0.02 fish m−2 in above-waterfall pools) and higher shrimp abundance in above-waterfall pools (eight shrimp/pool vs. less than one shrimp/pool in below-waterfall pools). However, macroinvertebrate densities (excluding shrimp) were similar among both pool types. Ambient periphyton was higher in below-waterfall pools in 2013 (4.3 vs. 2.8 g m−2 in above-waterfall pools) and 2014 (4.8 vs. 3.4 g m−2 in above-waterfall pools), while periphyton growth rates varied from 0.05 to 0.26 g m−2 days−1 and were significantly higher in below-waterfall pools in 2014. Leaf litter decomposition rates (0.001 to 0.024 days−1) did not differ between pool types, suggesting that neither shrimp nor fish densities had consistent impacts on this ecosystem function. Regardless, this research demonstrates the varied effects of biotic and abiotic factors on community structure and ecosystem function. Our results have highlighted the importance of discontinuities, such as waterfalls, in tropical streams.</p

Macroinvertebrate trophic structure on waterfalls in Borneo

Waterfalls have unique physical characteristics and harbour highly specialised macroinvertebrate communities, but have been the subject of very few ecological studies. There are no previous studies of trophic structure of waterfall assemblages. It was hypothesised that because of the steep gradient of waterfalls and low retention of terrestrial-based resources, the abundant basal food resources would be periphyton. In addition, because of the frequent scouring flood events, it was predicted that periphyton would be a significant source of food for filter feeders. Waterfalls in the Ulu Temburong National Park (Brunei Darussalam) were used in the present case study. Methods included stable carbon (C)- and nitrogen (N)-isotope analyses (SIA; δ13C and δ15N of leaf litter and periphyton) and gut-content analysis (GCA) of the most the abundant macroinvertebrates. With δ15N values ranging from –1.9 to 5.5‰, literature suggests that this indicates that herbivores (Heptageniidae and Blephariceridae), omnivores (Simuliidae and Hydropsychidae) and predators (Buccinidae) live in the waterfalls. Apart from Buccinidae, the taxa had δ13C signatures ranging from –33 to –26‰, with a high dependence on periphyton, which is similar to other tropical-stream biotopes. The present study suggests that despite scouring velocities, waterfalls support animals with a range of diets, based on grazing or scraping, filter feeding and predation

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

Katydids produce sound for signaling and communication by stridulation of the tegmina. Unlike crickets, most katydids are known to sing at ultrasonic frequencies. This has drawn interest in the investigation of the biophysics of ultrasonic sound production, detection, evolution, and ecology (including predator–prey interactions) of these katydids. However, most of these studies are based on species from the Neotropics, while little is known about katydid species from the hyperdiverse region of Southeast Asia. To address this, a concerted effort to document, record, and describe the calling songs of Southeast Asian katydids, especially species that call at ultrasonic frequencies, was made. A study spanning two years (2018–2020) in the 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 terms of time and frequency. 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.), with 87.5% of species having ultrasonic peak frequencies and 12.5% being considered extreme ultrasonic callers (peak frequency >40 kHz). The call spectrum ranges from tonal (e.g., spectral entropy is 6.8 in Casigneta sp. 2) to resonant (entropy is 8.8 in Conocephalus cognatus). Of the 24 species whose calls are described here, we imaged and described the sound-producing structures of 18. 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 these areas. Amassing a database of calling songs and sound-producing organ illustrations from different species is important to address taxonomic impediments while advancing our knowledge about the bioacoustics of Southeast Asian katydids

Inferring species boundaries using acoustic and morphological data in the ground cricket genus Gymnogryllus (Orthoptera: Grylloidea: Gryllinae)

10.1080/14772000.2018.1521479Systematics and Biodiversity168731-74