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A taxonomic description of all castes of Colobopsisexplodens Laciny & Zettel, sp. n. from Borneo, Thailand, and Malaysia is provided, which serves as a model species for biological studies on “exploding ants” in Southeast Asia. The new species is a member of the Colobopsiscylindrica (COCY) group and falls into a species complex that has been repeatedly summarized under the name Colobopsissaundersi (Emery, 1889) (formerly Camponotussaundersi). The COCY species group is known under its vernacular name “exploding ants” for a unique behaviour: during territorial combat, workers of some species sacrifice themselves by rupturing their gaster and releasing sticky and irritant contents of their hypertrophied mandibular gland reservoirs to kill or repel rivals. This study includes first illustrations and morphometric characterizations of males of the COCY group: Colobopsisexplodens Laciny & Zettel, sp. n. and Colobopsisbadia (Smith, 1857). Characters of male genitalia and external morphology are compared with other selected taxa of Camponotini. Preliminary notes on the biology of C.explodens Laciny & Zettel, sp. n. are provided. To fix the species identity of the closely related C.badia, a lectotype from Singapore is designated. The following taxonomic changes within the C.saundersi complex are proposed: Colobopsissolenobia (Menozzi, 1926), syn. n. and Colobopsistrieterica (Menozzi, 1926), syn. n. are synonymized with Colobopsiscorallina Roger, 1863, a common endemic species of the Philippines. Colobopsissaginata Stitz, 1925, stat. n., hitherto a subspecies of C.badia, is raised to species level.

Phytochemical investigation on a crude methanolic bark extract of Goniothalamus velutinus resulted in the isolation of four compounds, aristolactam I ( 1 ), aristolactam BII ( 2 ), aristolactam AII ( 3 ) and velutinam ( 4 ). Compounds ( 1 ) and ( 2 ) have previously been isolated from the bark of G. velutinus but this is the first report on isolation of compounds ( 3 ) and ( 4 ) from this specie. Antibacterial activities of these compounds were tested against Gram-positive bacteria ( Bacillus subtilis , Bacillus spizizenii and Staphylococcus aureus ) but none of them showed any antibacterial activity under the tested concentrations. These compounds were also tested for anti-biofilm activity against Klebsiella pneumoniae , S. aureus , Streptococcus mutans and Proteus mirabilis and among the four compounds only velutinam ( 4 ) (70 µg/mL) inhibited biofilm formation of both S. mutans and P. mirabilis up to 41.3 and 78.9%, respectively. Whereas, the compounds aristolactam BII ( 2 ) (90 µg/mL) and aristolactam AII ( 3 ) (140 µg/mL) were active against S. mutans and inhibited their biofilm formation to 72.8% and 89.9%, correspondingly. In addition aristolactam I ( 1 ) did not show any inhibition of biofilm against the microorganism used in this study. The anticancer activity of velutinam ( 4 ) was evaluated against various cell lines including Human lung adenocarcinoma epithelial cells (A549), human embryonic kidney cells (HEK 293) and epidermoid cervical carcinoma cells (CaSki). The MTT antiproliferative assay resulted in IC 50 values of 21.57 µg/mL, 13.28 µg/mL and 10.97 µg/mL for A549, HEK 293 and CaSki, respectively. Although anticancer activity of velutinam ( 4 ) has been reported on HeLa and L1210 cell lines, it has never been reported for the cell lines under this study. To our knowledge, this is the first report on anticancer activity of velutinam ( 4 ) on these cell lines.

Forty-five volatile organic compounds (VOCs) were identified or annotated in the mandibular gland reservoir content (MGRC) of the Southeast Asian ant Colobopsis explodens Laciny and Zettel, 2018 (Hymenoptera: Formicidae), using headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) and liquid extraction combined with GC-MS. In extension of previous reports on VOCs of C. explodens, members of different compound classes, such as alkanes, aliphatic and aromatic carboxylic acids, and phenolics, were detected. The ketone 2-heptanone and the biochemically related phenolics benzene-1,3,5-triol (phloroglucinol, PG), 1-(2,4,6-trihydroxyphenyl)ethanone (monoacetylphloroglucinol, MAPG), 5,7-dihydroxy-2-methylchromen-4-one (noreugenin), and 1-(3-Acetyl-2,4,6-trihydroxyphenyl)ethanone (2,4-diacetylphloroglucinol, DAPG) dominated the GC-MS chromatograms. The identities of the main phenolics MAPG and noreugenin were further verified by liquid chromatography-high resolution-tandem mass spectrometry (LC-HRMS/MS). A comparative study of MGRC samples originating from three distinct field expeditions revealed differences in the VOC profiles, but the presence and relative abundances of the dominating constituents were largely consistent in all samples. Our study considerably extends the knowledge about the number and type of VOCs occurring in the MGRC of C. explodens. Based on the type of the detected compounds, we propose that the likely irritant and antibiotic phenolic constituents play a role in defense against arthropod opponents or in protection against microbial pathogens.

Functional effects of ants in rainforest canopies depend on difficult to characterize ant diets. In Bornean dipterocarp forests, certain diurnal, arboreal, territorial, and ecologically dominant ‘COCY’ ant species (Colobopsis cylindrica clade) grazed epiphytic biofilms on adaxial leaf surfaces, as well as on tree trunks and branches. Microscopic examination of worker buccal pellets revealed numerous (mainly ascomycete) fungal spores, together with insect appendages and cuticle. Direct observations, video-imaging, and δ15N isotope data rule out feeding by predation, but isotopes cannot separate fungi from plant and insect exudates as principal nitrogen sources. Lipid-rich products, extracted from pellets in situ, are hypothesized sources of essential sterols. Also present in pellets were colorful mandibular gland (MG) compounds unique to this ant clade and deployed, as a derived character state, in suicidal defense of foraging territories. Mildly antimicrobial and highly adhesive MG products also occur basally in the clade and may have first evolved for roles in microbial sterilization and food-gathering and processing. Proteomic studies of YG COCY ants detected 2% proteins in hypertrophied, product-filled MG reservoirs, but SDS-PAGE qualitative analysis revealed mostly low-molecular mass proteins and peptides (8–15 kDa), too small for enzymes but consistent with membrane-binding proteins and/or antimicrobial peptides. Breakdown of chitin and chitosan in pellets may occur with enzymes derived from molting fluids in insect cuticle (proteases and chitinases) and/or fungi and bacteria. To the extent that COCY workers collect and consume pathogenic and/or beneficial phyllosphere microbes, ant effects on plants may be mediated by these activities. Abstrak Sejauh mana terdapat kesan fungsi semut di kanopi hutan hujan berasaskan kesukaran mengkaji pemakanan semut tersebut. Di dalam hutan dipterokarp Borneo spesies tertentu dari klad Camponotus (Colobopsis) cylindricus (spesies ‘COCY’) yang giat pada siang, tinggal di pokok, mempertahankan kawasan dan berekologi dominan didapati memakan lapisan nipis (biofilem) hidupan epifit pada permukaan daun dan juga batang dan dahan pokok. Pemerhatian pelet yang masih dalam mulut pekerja semut yang belum lagi tukar kepada produk yang berlipid tinggi mendedahkan banyak spora kulat (kebanyakannya ‘ascomycete’) yang tercampur dengan bahagian badan dan kutikal serangga. Pemerhatian dan data isotop δ15N menunjukkan ketiadaan predasi tetapi tidak dapat menunjukkan bahawa kulat dan cecair dari tumbuhan merupakan punca nitrogen utama. Pelet juga mengandungi kompaun glanda mandibular (MG) yang unik kepada klad semut tersebut yang digunakan oleh spesies-spesies yang tertentu dalam pertahanan kawasan pemakanan sehingga mati, iaitu satu ciri yang kemudian muncul. Produk MG yang kuat melekat mungkin muncul untuk memainkan peranan dalam pemungutan bahan makanan dan mungkin juga merendahkan kesan mikrob semasa pemerosesan makanan untuk dapat N dan/atau lipid (misalnya sterol sejati). Kajian proteomik dapat mengesani protin sebanyak 2 peratus yang terkandung di dalam takungan MG yang diisikan dengan produk, juga penganalisis kualitatif SDS-PAGE menunjukkan protin dan peptid yang bermolekular rendah (8-15 kDa) yang terlalu halus bagi enzim tetapi boleh jadi protin pengikatan membran atau peptid antimikrob. Penghancuran kitin dan kitosan dalam bahan pelet mungkin berlaku berkesan dari enzim yang berpunca dari kutikal serangga (yang mengandungi kitinas) dan/atau kulat dan bakteria. Kesan semut ke atas tumbuh-tumbuhan kemungkinan dipengaruhi aktiviti tersebut sejauh mana pekerja COCY memungut dan makan mikrob filoplan yang patogenik dan/atau berguna.

Unlike most other fungi, molds of the genus Trichoderma (Hypocreales, Ascomycota) are aggressive parasites of other fungi and efficient decomposers of plant biomass. Although nutritional shifts are common among hypocrealean fungi, there are no examples of such broad substrate versatility as that observed in Trichoderma. A phylogenomic analysis of 23 hypocrealean fungi (including nine Trichoderma spp. and the related Escovopsis weberi) revealed that the genus Trichoderma has evolved from an ancestor with limited cellulolytic capability that fed on either fungi or arthropods. The evolutionary analysis of Trichoderma genes encoding plant cell wall-degrading carbohydrate-active enzymes and auxiliary proteins (pcwdCAZome, 122 gene families) based on a gene tree / species tree reconciliation demonstrated that the formation of the genus was accompanied by an unprecedented extent of lateral gene transfer (LGT). Nearly one-half of the genes in Trichoderma pcwdCAZome (41%) were obtained via LGT from plant-associated filamentous fungi belonging to different classes of Ascomycota, while no LGT was observed from other potential donors. In addition to the ability to feed on unrelated fungi (such as Basidiomycota), we also showed that Trichoderma is capable of endoparasitism on a broad range of Ascomycota, including extant LGT donors. This phenomenon was not observed in E. weberi and rarely in other mycoparasitic hypocrealean fungi. Thus, our study suggests that LGT is linked to the ability of Trichoderma to parasitize taxonomically related fungi (up to adelphoparasitism in strict sense). This may have allowed primarily mycotrophic Trichoderma fungi to evolve into decomposers of plant biomass., Author summary Individual fungi rely on particular host organisms or substrates for their nutrition. Therefore, the genomes of fungi feeding on plant biomass necessarily contain genes encoding plant cell wall-degrading enzymes, while animal parasites may depend on proteolytic activity. Molds in the genus Trichoderma (Ascomycota) display a unique nutritional versatility. They can feed on other fungi, attack animals, and degrade plant debris. The later property is so efficient that one species (T. reesei) is commercially used for the production of cellulolytic enzymes required for making biofuels and other industry. In this work, we have investigated the evolution of proteins required for plant cell wall degradation in nine Trichoderma genomes and found an unprecedented number of lateral gene transfer (LGT) events for genes encoding these enzymes. Interestingly, the transfers specifically occurred from Ascomycota molds that feed on plants. We detected no cases of LGT from other fungi (e.g., mushrooms or wood-rotting fungi from Basidiomycota) that are frequent hosts of Trichoderma. Therefore, we propose that LGT may be linked to the ability of Trichoderma to parasitize on related organisms. This is a characteristic ecological trait that distinguishes Trichoderma from other mycoparasitic fungi. In this report, we demonstrate that the lateral transfer of genes may result in a profound nutritional expansion and contribute to the emergence of a generalist capable of feeding on organic matter of any origin.

Summary: Tropical forest above-ground wood production (AGWP) varies substantially along environmental gradients. Some evidence suggests that AGWP may vary between regions and specifically that Asian forests have particularly high AGWP. However, comparisons across biogeographic regions using standardized methods are lacking, limiting our assessment of pan-tropical variation in AGWP and potential causes. We sampled AGWP in NW Amazon (17 long-term forest plots) and N Borneo (11 plots), both with abundant year-round precipitation. Within each region, forests growing on a broad range of edaphic conditions were sampled using standardized soil and forest measurement techniques. Plot-level AGWP was 49% greater in Borneo than in Amazonia (9.73 ± 0.56 vs. 6.53 ± 0.34 Mg dry mass ha -1 a -1 , respectively; regional mean ± 1 SE). AGWP was positively associated with soil fertility (PCA axes, sum of bases and total P). After controlling for the edaphic environment, AGWP remained significantly higher in Bornean plots. Differences in AGWP were largely attributable to differing height-diameter allometry in the two regions and the abundance of large trees in Borneo. This may be explained, in part, by the greater solar radiation in Borneo compared with NW Amazonia. Trees belonging to the dominant SE Asian family, Dipterocarpaceae, gained woody biomass faster than otherwise equivalent, neighbouring non-dipterocarps, implying that the exceptional production of Bornean forests may be driven by floristic elements. This dominant SE Asian family may partition biomass differently or be more efficient at harvesting resources and in converting them to woody biomass. Synthesis. N Bornean forests have much greater AGWP rates than those in NW Amazon when soil conditions and rainfall are controlled for. Greater resource availability and the highly productive dipterocarps may, in combination, explain why Asian forests produce wood half as fast again as comparable forests in the Amazon. Our results also suggest that taxonomic groups differ in their fundamental ability to capture carbon and that different tropical regions may therefore have different carbon uptake capacities due to biogeographic history. North Bornean forests have much greater AGWP rates than those in north-western Amazon when soil conditions and rainfall are controlled for. Greater resource availability and the highly productive dipterocarps may, in combination, explain why these Asian forests produce wood half as fast again as comparable forests in the Amazon. Our results also suggest that taxonomic groups differ in their fundamental ability to capture carbon and that different tropical regions may therefore have different carbon uptake capacities due to biogeographic history.

Plant habitat associations are well documented in Bornean lowland tropical forests, but few studies contrast the prevalence of associations across sites. We examined habitat associations and community composition of Dipterocarpaceae trees in two contrasting Bornean lowland mixed dipterocarp forests separated by approximately 100 km: Andulau (uniform topography, lower altitudinal range, sandy soils) and Belalong (highly dissected topography, higher altitudinal range, clay-rich soils). Dipterocarpaceae trees ≥ 1 cm diameter at breast height (dbh) were censused in 20-m wide belt transects established along topographic gradients at each site. Dipterocarp density, evenness, species richness, and diversity were significantly higher at Andulau than Belalong. Significant site associations (with either Andulau or Belalong) were detected for 19 (52%) of the 37 dipterocarp species tested. Dipterocarpaceae community composition at Belalong correlated with soil nutrient concentrations as well as measures of vegetation and topographic structure, but community composition at Andulau correlated with fewer habitat variables. Within each site, dipterocarp density, species richness, and diversity were consistently higher on ridges than in slopes and valleys. Significant within-site associations to topographic habitats were less common at Andulau (10% of species tested) than at Belalong (15%). We conclude that edaphic and other environmental factors influence dipterocarp community composition at a local scale, and are more important drivers of community structure in the more variable environment at Belalong. Species richness and diversity of dipterocarps on small plots, however, were higher at Andulau, suggesting that factors other than environmental heterogeneity contribute to contrasts in dipterocarp tree species richness at small scales.

This study investigated the contribution of termites to mass loss of dead wood ( Macaranga bancana , Elateriospermum tapos , and Dillenia beccariana ) in a lowland tropical rainforest, Brunei Darussalam. Mesh bag method was used to exclude termites, and the mass remaining was monitored after 3, 7, 13, and 23 months. C/N ratio of the samples was analyzed after 13 and 23 months. Initial wood density was 0.63, 0.92, and 1.02 g/cm 3 for M. bancana , E. tapos , and D. beccariana , respectively, and the termite contribution to mass loss was an average (range) of 13.05±5.68 (4.17-29.59%), 3.48±1.13 (2.20-6.49), and 3.40±1.92% (0.74-10.78), respectively. Until 7 months, termites contributed highly to mass loss, given the low initial wood density, and interaction effect of species and treatment was significant. After 7 months, the contribution decreased in M. bancana and E. tapos , whereas it increased consistently in D. beccariana . The interaction effect was not significant, whereas differences in C/N ratio among the species were significant, with a lower C/N ratio in M. bancana and E. tapos than in D. beccariana . After 23 months, the differences in C/N ratio were not significant, and ants were present at 40% of control samples in M. bancana and E. tapos . Our results suggest that the contribution of termites to mass loss varies by dead wood species and is temporally variable. Initial wood traits could affect the termite feeding in the beginning, however, termites thereafter could forage in response to the varying C/N ratio among species and predators.

Two diverse population of Molinia caerulea (L.) Moench, one growing on a Ca 2+ -rich, alkaline, Leblanc waste tip, the other on an acid moorland, were investigated. It was anticipated that a comparative study of the morphology, growth and flowering patterns, protein composition, specific isoenzyme and root-surface phosphatase activities of both populations would clarify the taxonomic status of populations of Molinia and help towards understanding the ability of M. caerulea to colonize widely differing habitats. Both populations were identified as Molinia caerulea caerulea . The Molinia growing on Leblanc spoil displayed characteristics typified by r-selected plants, i.e. displaying larger flowers after faster development. Acid moorland plants showed greater vegetative development and were more typical of K-selected types. These differences between the more vigorous shoot growth of the moorland compared to the waste tip plants persisted under controlled conditions, irrespective of the media in which they were grown. Root surface phosphatase activity showed a plastic response to edaphic pH which may contribute to the success of M. caerulea caerulea in colonizing diverse habitats.

Summary • High foliar concentrations of aluminium (Al) have been reported in numerous plant species, but progress on the understanding of the functional significance of this trait is constrained by the absence of a quantitative analysis of its distribution among plant lineages and across biomes. • We constructed a global dataset of foliar Al and nutrient concentrations for 1044 plant species from literature sources and new data collections in Brunei Darussalam. • Our results provide statistical support for the existence of Al accumulators and non-Al accumulators in global, regional and local floras based on foliar Al concentrations. A value of 1 mg Al g−1 leaf dry mass is a suitable threshold to distinguish between these two groups in a sample of species that lacks any geographical reference. However, a higher threshold foliar Al concentration is required to distinguish between Al accumulators in tropical (2.3–3.9 mg Al g−1 leaf dry mass) than in temperate (1.1 mg Al g−1 leaf dry mass) floras. There was a phylogenetic signal in the foliar concentrations of Al, but phylogeny did not explain the difference in the mean foliar Al concentration between tropical and temperate floras in a phylogenetically controlled analysis. • Phylogeny and soil chemistry are potential factors driving Al accumulation in certain groups of plants.

Although recent methodological advances have allowed the incorporation of rate variation in molecular dating analyses, the calibration procedure, performed mainly through fossils, remains resistant to improvements. One source of uncertainty pertains to the assignment of fossils to specific nodes in a phylogeny, especially when alternative possibilities exist that can be equally justified on morphological grounds. Here we expand on a recently developed fossil cross-validation method to evaluate whether alternative nodal assignments of multiple fossils produce calibration sets that differ in their internal consistency. We use an enlarged Crypteroniaceae-centered phylogeny of Myrtales, six fossils, and 72 combinations of calibration points, termed calibration sets, to identify (i) the fossil assignments that produce the most internally consistent calibration sets and (ii) the mean ages, derived from these calibration sets, for the split of the Southeast Asian Crypteroniaceae from their West Gondwanan sister clade (node X). We found that a correlation exists between s values, devised to measure the consistency among the calibration points of a calibration set (Near and Sanderson, 2004), and nodal distances among calibration points. By ranking all sets according to the percent deviation of s from the regression line with nodal distance, we identified the sets with the highest level of corrected calibration-set consistency. These sets generated lower standard deviations associated with the ages of node X than sets characterized by lower corrected consistency. The three calibration sets with the highest corrected consistencies produced mean age estimates for node X of 79.70, 79.14, and 78.15 My. These timeframes are most compatible with the hypothesis that the Crypteroniaceae stem lineage dispersed from Africa to the Deccan plate as it drifted northward during the Late Cretaceous.