Displaying publications 21 - 40 of 194 in total

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  1. Impacts of selective logging on the oxidative status of tropical understorey birds
    Messina S, Edwards DP, AbdElgawad H, Beemster GTS, Tomassi S, Benedick S, et al.
    J Anim Ecol, 2020 10;89(10):2222-2234.
    PMID: 32535926 DOI: 10.1111/1365-2656.13280
    Selective logging is the dominant form of human disturbance in tropical forests, driving changes in the abundance of vertebrate and invertebrate populations relative to undisturbed old-growth forests. A key unresolved question is understanding which physiological mechanisms underlie different responses of species and functional groups to selective logging. Regulation of oxidative status is thought to be one major physiological mechanism underlying the capability of species to cope with environmental changes. Using a correlational cross-sectional approach, we compared a number of oxidative status markers among 15 understorey bird species in unlogged and selectively logged forest in Borneo in relation to their feeding guild. We then tested how variation of markers between forest types was associated with that in population abundance. Birds living in logged forests had a higher activity of the antioxidant enzyme superoxide dismutase and a different regulation of the glutathione cycle compared to conspecific birds in unlogged forest. However, neither oxidative damage nor oxidized glutathione differed between forest types. We also found that omnivores and insectivores differed significantly in all markers related to the key cellular antioxidant glutathione irrespective of the forest type. Species with higher levels of certain antioxidant markers in a given type of forest were less abundant in that forest type compared to the other. Our results suggest that there was little long-term effect of logging (last logging rotation occurred ~15 years prior to the study) on the oxidative status of understorey bird species. However, it is unclear if this was owing to plasticity or evolutionary change. Our correlative results also point to a potential negative association between some antioxidants and population abundance irrespective of the forest type.
  2. Fulltext Relapse to opioid use in opioid-dependent individuals released from compulsory drug detention centres compared with those from voluntary methadone treatment centres in Malaysia: a two-arm, prospective observational study
    Wegman MP, Altice FL, Kaur S, Rajandaran V, Osornprasop S, Wilson D, et al.
    Lancet Glob Health, 2017 02;5(2):e198-e207.
    PMID: 27964869 DOI: 10.1016/S2214-109X(16)30303-5
    BACKGROUND: Detention of people who use drugs into compulsory drug detention centres (CDDCs) is common throughout East and Southeast Asia. Evidence-based pharmacological therapies for treating substance use disorders, such as opioid agonist treatments with methadone, are generally unavailable in these settings. We used a unique opportunity where CDDCs coexisted with voluntary drug treatment centres (VTCs) providing methadone in Malaysia to compare the timing and occurrence of opioid relapse (measured using urine drug testing) in individuals transitioning from CDDCs versus methadone maintenance in VTCs.

    METHODS: We did a parallel, two-arm, prospective observational study of opioid-dependent individuals aged 18 years and older who were treated in Malaysia in the Klang Valley in two settings: CDDCs and VTCs. We used sequential sampling to recruit individuals. Assessed individuals in CDDCs were required to participate in services such as counselling sessions and manual labour. Assessed individuals in VTCs could voluntarily access many of the components available in CDDCs, in addition to methadone therapy. We undertook urinary drug tests and behavioural interviews to assess individuals at baseline and at 1, 3, 6, 9, and 12 months post-release. The primary outcome was time to opioid relapse post-release in the community confirmed by urinary drug testing in individuals who had undergone baseline interviewing and at least one urine drug test (our analytic sample). Relapse rates between the groups were compared using time-to-event methods. This study is registered at ClinicalTrials.gov (NCT02698098).

    FINDINGS: Between July 17, 2012, and August 21, 2014, we screened 168 CDDC attendees and 113 VTC inpatients; of these, 89 from CDDCs and 95 from VTCs were included in our analytic sample. The baseline characteristics of the two groups were similar. In unadjusted analyses, CDDC participants had significantly more rapid relapse to opioid use post-release compared with VTC participants (median time to relapse 31 days [IQR 26-32] vs 352 days [256-unestimable], log rank test, p<0·0001). VTC participants had an 84% (95% CI 75-90) decreased risk of opioid relapse after adjustment for control variables and inverse propensity of treatment weights. Time-varying effect modelling revealed the largest hazard ratio reduction, at 91% (95% CI 83-96), occurs during the first 50 days in the community.

    INTERPRETATION: Opioid-dependent individuals in CDDCs are significantly more likely to relapse to opioid use after release, and sooner, than those treated with evidence-based treatments such as methadone, suggesting that CDDCs have no role in the treatment of opioid-use disorders.

    FUNDING: The World Bank Group, Doris Duke Charitable Foundation, National Institute on Drug Abuse, Australian National Health & Medical Research Council, National Institute of Mental Health, and the University of Malaya-Malaysian Ministry of Higher Education High Impact Research Grant.

  3. A distinctive new species of flowerpecker (Passeriformes: Dicaeidae) from Borneo
    Saucier JR, Milensky CM, Caraballo-Ortiz MA, Ragai R, Dahlan NF, Edwards DP
    Zootaxa, 2019 Oct 17;4686(4):zootaxa.4686.4.1.
    PMID: 31719467 DOI: 10.11646/zootaxa.4686.4.1
    The enigmatic 'Spectacled Flowerpecker'-a probable new bird species from the island of Borneo-was first sighted in the Danum Valley of Sabah, Malaysia in 2009. However, the absence of a holotype specimen has prevented its formal scientific description. Since then only a handful of reports from widely disparate localities across the island have emerged, all from lowland sites and often in close association with fruiting mistletoe. Here, we report the long-awaited capture of a specimen of this putative new species and confirm its morphological and molecular distinctiveness as a novel species in the genus Dicaeum.
  4. Fulltext Imaging recommendations and algorithms for pediatric tuberculosis: part 1-thoracic tuberculosis
    Concepcion NDP, Laya BF, Andronikou S, Abdul Manaf Z, Atienza MIM, Sodhi KS
    Pediatr Radiol, 2023 Aug;53(9):1773-1781.
    PMID: 37081179 DOI: 10.1007/s00247-023-05654-1
    Tuberculosis (TB) remains a global health problem and is the second leading cause of death from a single infectious agent, behind the novel coronavirus disease of 2019. Children are amongst the most vulnerable groups affected by TB, and imaging manifestations are different in children when compared to adults. TB primarily involves the lungs and mediastinal lymph nodes. Clinical history, physical examination, laboratory examinations and various medical imaging tools are combined to establish the diagnosis. Even though chest radiography is the accepted initial radiological imaging modality for the evaluation of children with TB, this paper, the first of two parts, aims to discuss the advantages and limitations of the various medical imaging modalities and to provide recommendations on which is most appropriate for the initial diagnosis and assessment of possible complications of pulmonary TB in children. Practical, evidence-based imaging algorithms are also presented.
  5. Imaging recommendations and algorithms for pediatric tuberculosis: part 2-extrathoracic tuberculosis
    Laya BF, Concepcion NDP, Andronikou S, Abdul Manaf Z, Atienza MIM, Sodhi KS
    Pediatr Radiol, 2023 Aug;53(9):1782-1798.
    PMID: 37074457 DOI: 10.1007/s00247-023-05650-5
    Despite advances in diagnosis and treatment in recent years, tuberculosis (TB) remains a global health concern. Children are amongst the most vulnerable groups affected by this disease. Although TB primarily involves the lungs and mediastinal lymph nodes, it can affect virtually any organ system of the body. Along with clinical history combined with physical examination and laboratory tests, various medical imaging tools help establish the diagnosis. Medical imaging tests are also helpful for follow-up during therapy, to assess complications and exclude other underlying pathologies. This article aims to discuss the utility, strengths and limitations of medical imaging tools in the evaluation of suspected extrathoracic TB in the pediatric population. Imaging recommendations for the diagnosis will be presented along with practical and evidence-based imaging algorithms to serve as a guide for both radiologists and clinicians.
  6. Fulltext Last exit before the brink: Conservation genomics of the Cambodian population of the critically endangered southern river terrapin
    Çilingir FG, Seah A, Horne BD, Som S, Bickford DP, Rheindt FE
    Ecol Evol, 2019 Sep;9(17):9500-9510.
    PMID: 31534671 DOI: 10.1002/ece3.5434
    The southern river terrapin, Batagur affinis is one of the world's 25 most endangered freshwater turtle species. The major portion of the global population is currently found in peninsular Malaysia, with the only remnant Indochinese population in southern Cambodia. For more than a decade, wild nests in this remnant Cambodian population have been fenced and hatchlings reared in captivity. Here we amplified 10 microsatellite markers from all 136 captive individuals, obtained 2,658 presumably unlinked and neutral single nucleotide polymorphisms from 72 samples with ddRAD-seq, and amplified 784 bp of mtDNA from 50 samples. Our results reveal that the last Indochinese population comprised only four kinship groups as of 2012, with all offspring sired from <10 individuals in the wild. We demonstrate an obvious decrease in genetic contributions of breeders in the wild from 2006-2012 and identify high-value breeders instrumental for ex-situ management of the contemporary genetic stock of the species.
  7. Fulltext Effects of a 7-Day Pornography Abstinence Period on Withdrawal-Related Symptoms in Regular Pornography Users: A Randomized Controlled Study
    Fernandez DP, Kuss DJ, Justice LV, Fernandez EF, Griffiths MD
    Arch Sex Behav, 2023 May;52(4):1819-1840.
    PMID: 36652136 DOI: 10.1007/s10508-022-02519-w
    Little is known about whether withdrawal-like symptoms manifest when regular pornography users attempt to abstain from pornography. The present study used a randomized controlled design to examine whether (1) negative abstinence effects that may be potentially reflective of withdrawal-related symptoms manifest when a non-clinical sample of regular pornography users attempt to abstain from pornography for a 7-day period and (2) these negative abstinence effects would only manifest (or manifest more strongly) for those with higher levels of problematic pornography use (PPU). A total of 176 undergraduate students (64.2% female) who were regular pornography users (defined as having used pornography ≥ three times a week in the past 4 weeks) were randomly assigned to an abstinence group (instructed to attempt abstinence from pornography for 7 days, n = 86) or a control group (free to watch pornography as usual, n = 90). Participants completed measures of craving, positive and negative affect, and withdrawal symptoms at baseline and each night of the 7-day period. Contrary to the confirmatory hypotheses, there were no significant main effects of group (abstinence vs. control) or group × PPU interaction effects on any of the outcome measures, controlling for baseline scores. These findings indicate that no evidence of withdrawal-related symptoms was found for abstaining participants, and this was not dependent on level of PPU. However, exploratory analyses showed a significant three-way interaction (group × PPU × past 4-week frequency of pornography use [FPU]) on craving, where an abstinence effect on craving was found at high levels of PPU only once past 4-week FPU reached the threshold of daily use. While these exploratory findings should be interpreted with caution, they suggest that abstinence effects could potentially manifest when there is a combination of high PPU and high FPU-a hypothesis that warrants investigation in future prospective abstinence studies.
  8. Fulltext Island Biogeography Revisited: Museomics Reveals Affinities of Shelf Island Birds Determined by Bathymetry and Paleo-Rivers, Not by Distance to Mainland
    Garg KM, Chattopadhyay B, Cros E, Tomassi S, Benedick S, Edwards DP, et al.
    Mol Biol Evol, 2022 Jan 07;39(1).
    PMID: 34893875 DOI: 10.1093/molbev/msab340
    Island biogeography is one of the most powerful subdisciplines of ecology: its mathematical predictions that island size and distance to mainland determine diversity have withstood the test of time. A key question is whether these predictions follow at a population-genomic level. Using rigorous ancient-DNA protocols, we retrieved approximately 1,000 genomic markers from approximately 100 historic specimens of two Southeast Asian songbird complexes from across the Sunda Shelf archipelago collected 1893-1957. We show that the genetic affinities of populations on small shelf islands defy the predictions of geographic distance and appear governed by Earth-historic factors including the position of terrestrial barriers (paleo-rivers) and persistence of corridors (Quaternary land bridges). Our analyses suggest that classic island-biogeographic predictors may not hold well for population-genomic dynamics on the thousands of shelf islands across the globe, which are exposed to dynamic changes in land distribution during Quaternary climate change.
  9. Fulltext Limited contributions of plant pathogens to density-dependent seedling mortality of mast fruiting Bornean trees
    Cannon PG, O'Brien MJ, Yusah KM, Edwards DP, Freckleton RP
    Ecol Evol, 2020 Dec;10(23):13154-13164.
    PMID: 33304525 DOI: 10.1002/ece3.6906
    Fungal pathogens are implicated in driving tropical plant diversity by facilitating strong, negative density-dependent mortality of conspecific seedlings (C-NDD). Assessment of the role of fungal pathogens in mediating coexistence derives from relatively few tree species and predominantly the Neotropics, limiting our understanding of their role in maintaining hyper-diversity in many tropical forests. A key question is whether fungal pathogen-mediated C-NDD seedling mortality is ubiquitous across diverse plant communities. Using a manipulative shadehouse experiment, we tested the role of fungal pathogens in mediating C-NDD seedling mortality of eight mast fruiting Bornean trees, typical of the species-rich forests of South East Asia. We demonstrate species-specific responses of seedlings to fungicide and density treatments, generating weak negative density-dependent mortality. Overall seedling mortality was low and likely insufficient to promote overall community diversity. Although conducted in the same way as previous studies, we find little evidence that fungal pathogens play a substantial role in determining patterns of seedling mortality in a SE Asian mast fruiting forest, questioning our understanding of how Janzen-Connell mechanisms structure the plant communities of this globally important forest type.
  10. Therapeutic potential of culinary-medicinal mushrooms for the management of neurodegenerative diseases: diversity, metabolite, and mechanism
    Phan CW, David P, Naidu M, Wong KH, Sabaratnam V
    Crit Rev Biotechnol, 2015;35(3):355-68.
    PMID: 24654802 DOI: 10.3109/07388551.2014.887649
    Mushrooms have long been used not only as food but also for the treatment of various ailments. Although at its infancy, accumulated evidence suggested that culinary-medicinal mushrooms may play an important role in the prevention of many age-associated neurological dysfunctions, including Alzheimer's and Parkinson's diseases. Therefore, efforts have been devoted to a search for more mushroom species that may improve memory and cognition functions. Such mushrooms include Hericium erinaceus, Ganoderma lucidum, Sarcodon spp., Antrodia camphorata, Pleurotus giganteus, Lignosus rhinocerotis, Grifola frondosa, and many more. Here, we review over 20 different brain-improving culinary-medicinal mushrooms and at least 80 different bioactive secondary metabolites isolated from them. The mushrooms (either extracts from basidiocarps/mycelia or isolated compounds) reduced beta amyloid-induced neurotoxicity and had anti-acetylcholinesterase, neurite outgrowth stimulation, nerve growth factor (NGF) synthesis, neuroprotective, antioxidant, and anti-(neuro)inflammatory effects. The in vitro and in vivo studies on the molecular mechanisms responsible for the bioactive effects of mushrooms are also discussed. Mushrooms can be considered as useful therapeutic agents in the management and/or treatment of neurodegeneration diseases. However, this review focuses on in vitro evidence and clinical trials with humans are needed.
  11. Fulltext Neurite outgrowth stimulatory effects of culinary-medicinal mushrooms and their toxicity assessment using differentiating Neuro-2a and embryonic fibroblast BALB/3T3
    Phan CW, David P, Naidu M, Wong KH, Sabaratnam V
    BMC Complement Altern Med, 2013;13:261.
    PMID: 24119256 DOI: 10.1186/1472-6882-13-261
    Mushrooms are not only regarded as gourmet cuisine but also as therapeutic agent to promote cognition health. However, little toxicological information is available regarding their safety. Therefore, the aim of this study was to screen selected ethno-pharmacologically important mushrooms for stimulatory effects on neurite outgrowth and to test for any cytotoxicity.
  12. Fulltext Pleurotus giganteus (Berk.) Karunarathna & K.D. Hyde: Nutritional value and in vitro neurite outgrowth activity in rat pheochromocytoma cells
    Phan CW, Wong WL, David P, Naidu M, Sabaratnam V
    BMC Complement Altern Med, 2012;12:102.
    PMID: 22812497 DOI: 10.1186/1472-6882-12-102
    Drugs dedicated to alleviate neurodegenerative diseases like Parkinson's and Alzheimer's have always been associated with debilitating side effects. Medicinal mushrooms which harness neuropharmacological compounds offer a potential possibility for protection against such diseases. Pleurotus giganteus (formerly known as Panus giganteus) has been consumed by the indigenous people in Peninsular Malaysia for many years. Domestication of this wild mushroom is gaining popularity but to our knowledge, medicinal properties reported for this culinary mushroom are minimal.
  13. Fulltext Neuronal health - can culinary and medicinal mushrooms help?
    Sabaratnam V, Kah-Hui W, Naidu M, Rosie David P
    J Tradit Complement Med, 2013 Jan;3(1):62-8.
    PMID: 24716157 DOI: 10.4103/2225-4110.106549
    Hericium erinaceus a culinary and medicinal mushroom is a well established candidate for brain and nerve health. Ganoderma lucidum, Grifola frondosa and Sarcodon scabrosus have been reported to have neurite outgrowth and neuronal health benefits. The number of mushrooms, however, studied for neurohealth activity are few compared to the more than 2 000 species of edible and / or medicinal mushrooms identified. In the on-going search for other potent culinary and / or medicinal mushrooms, indigenous mushrooms used in traditional medicines such as Lignosus rhinocerotis and Ganoderma neo-japonicum are also being investigated. Further, the edible mushroom, Pleurotus giganteus can be a potential candidate, too. Can these edible and medicinal mushrooms be tapped to tackle the health concerns of the aging population which is projected to be more than 80-90 million of people age 65 and above in 2050 who may be affected by age-related neurodegenerative disorders. Scientific validation is needed if these mushrooms are to be considered and this can be achieved by understanding the molecular and biochemical mechanisms involved in the stimulation of neurite outgrowth. Though it is difficult to extrapolate the in vitro studies to what may happen in the human brain, studies have shown that there can be improvement in cognitive abilities of the aged if the mushroom is incorporated in their daily diets.
  14. Fulltext Nine fatal cases of puffer fish poisoning in Sabah, Malaysia
    Kan SKP, Chan MKC, David P
    Med J Malaysia, 1987 Sep;42(3):199-200.
    PMID: 3506645
    The puffer fish belongs to the family Tetraodontidae and has one identifying characteristic which is the ability to inflate itself by gulping in large quantities of air or water. They are commonly found in estuarine and inshore water. The viscera (ovaries, testes and liver) of puffer fish contain varying amounts of extremely potent toxins [tetraodontoxin). The most violent form of fish poisoning is produced by ingestion of tetraodontoid or puffer-like fishes and this has been reported. The putftoad, Tetradon maculatum, has caused fatal poisoning? Despite the high toxicity of this group of fish, the meat is commonly consumed by some fisherman in Sabah without much morbidity. In Japan, puffer fish, called "fuqu" commands the highest prices in food fish and are prepared and sold in special restaurants where specially trained cooks are employed to prepare the "fuqu". Nevertheless it is still the primary cause of food poisoning in Japan especially among the lower socio-economic classes who fail to take the necessary precautions. In Sabah, four cases of puffer fish poisoning resulting in one death have been documented." We report herewith another incidence of puffer fish poisoning in which 18 persons from seven families were affected with nine deaths from two families.
  15. Fulltext Uridine from Pleurotus giganteus and Its Neurite Outgrowth Stimulatory Effects with Underlying Mechanism
    Phan CW, David P, Wong KH, Naidu M, Sabaratnam V
    PLoS One, 2015;10(11):e0143004.
    PMID: 26565787 DOI: 10.1371/journal.pone.0143004
    Neurodegenerative diseases are linked to neuronal cell death and impairment of neurite outgrowth. An edible mushroom, Pleurotus giganteus was found to stimulate neurite outgrowth in vitro but the chemical constituents and the underlying mechanism is yet to be elucidated. The chemical constituents of P. giganteus (linoleic acid, oleic acid, cinnamic acid, caffeic acid, p-coumaric acid, succinic acid, benzoic acid, and uridine) were tested for neurite outgrowth activity. Uridine (100 μM) was found to increase the percentage of neurite-bearing cells of differentiating neuroblastoma (N2a) cells by 43.1 ± 0.5%, which was 1.8-fold higher than NGF (50 ng/mL)-treated cells. Uridine which was present in P. giganteus (1.80 ± 0.03 g/100g mushroom extract) increased the phosphorylation of extracellular-signal regulated kinases (ERKs) and protein kinase B (Akt). Further, phosphorylation of the mammalian target of rapamycin (mTOR) was also increased. MEK/ERK and PI3K-Akt-mTOR further induced phosphorylation of cAMP-response element binding protein (CREB) and expression of growth associated protein 43 (GAP43); all of which promoted neurite outgrowth of N2a cells. This study demonstrated that P. giganteus may enhance neurite outgrowth and one of the key bioactive molecules responsible for neurite outgrowth is uridine.
  16. Hericium erinaceus (Bull.: Fr.) Pers., a medicinal mushroom, activates peripheral nerve regeneration
    Wong KH, Kanagasabapathy G, Naidu M, David P, Sabaratnam V
    Chin J Integr Med, 2016 Oct;22(10):759-67.
    PMID: 25159861 DOI: 10.1007/s11655-014-1624-2
    OBJECTIVE: To study the ability of aqueous extract of Hericium erinaceus mushroom in the treatment of nerve injury following peroneal nerve crush in Sprague-Dawley rats.

    METHODS: Aqueous extract of Hericium erinaceus was given by daily oral administration following peroneal nerve crush injury in Sprague-Dawley rats. The expression of protein kinase B (Akt) and mitogen-activated protein kinase (MAPK) signaling pathways; and c-Jun and c-Fos genes were studied in dorsal root ganglia (DRG) whereas the activity of protein synthesis was assessed in peroneal nerves by immunohistochemical method.

    RESULTS: Peripheral nerve injury leads to changes at the axonal site of injury and remotely located DRG containing cell bodies of sensory afferent neurons. Immunofluorescence studies showed that DRG neurons ipsilateral to the crush injury in rats of treated groups expressed higher immunoreactivities for Akt, MAPK, c-Jun and c-Fos as compared with negative control group (P <0.05). The intensity of nuclear ribonucleoprotein in the distal segments of crushed nerves of treated groups was significantly higher than in the negative control group (P <0.05).

    CONCLUSION: H. erinaceus is capable of promoting peripheral nerve regeneration after injury. Potential signaling pathways include Akt, MAPK, c-Jun, and c-Fos, and protein synthesis have been shown to be involved in its action.

  17. Fulltext The West Nile virus-like flavivirus Koutango is highly virulent in mice due to delayed viral clearance and the induction of a poor neutralizing antibody response
    Prow NA, Setoh YX, Biron RM, Sester DP, Kim KS, Hobson-Peters J, et al.
    J Virol, 2014 Sep 1;88(17):9947-62.
    PMID: 24942584 DOI: 10.1128/JVI.01304-14
    The mosquito-borne West Nile virus (WNV) is responsible for outbreaks of viral encephalitis in humans, horses, and birds, with particularly virulent strains causing recent outbreaks of disease in eastern Europe, the Middle East, North America, and Australia. Previous studies have phylogenetically separated WNV strains into two main genetic lineages (I and II) containing virulent strains associated with neurological disease. Several WNV-like strains clustering outside these lineages have been identified and form an additional five proposed lineages. However, little is known about whether these strains have the potential to induce disease. In a comparative analysis with the highly virulent lineage I American strain (WNVNY99), the low-pathogenicity lineage II strain (B956), a benign Australian strain, Kunjin (WNVKUN), the African WNV-like Koutango virus (WNVKOU), and a WNV-like isolate from Sarawak, Malaysia (WNVSarawak), were assessed for neuroinvasive properties in a murine model and for their replication kinetics in vitro. While WNVNY99 replicated to the highest levels in vitro, in vivo mouse challenge revealed that WNVKOU was more virulent, with a shorter time to onset of neurological disease and higher morbidity. Histological analysis of WNVKOU- and WNVNY99-infected brain and spinal cords demonstrated more prominent meningoencephalitis and the presence of viral antigen in WNVKOU-infected mice. Enhanced virulence of WNVKOU also was associated with poor viral clearance in the periphery (sera and spleen), a skewed innate immune response, and poor neutralizing antibody development. These data demonstrate, for the first time, potent neuroinvasive and neurovirulent properties of a WNV-like virus outside lineages I and II.
  18. Fulltext Degraded lands worth protecting: the biological importance of Southeast Asia's repeatedly logged forests
    Edwards DP, Larsen TH, Docherty TD, Ansell FA, Hsu WW, Derhé MA, et al.
    Proc Biol Sci, 2011 Jan 7;278(1702):82-90.
    PMID: 20685713 DOI: 10.1098/rspb.2010.1062
    Southeast Asia is a hotspot of imperiled biodiversity, owing to extensive logging and forest conversion to oil palm agriculture. The degraded forests that remain after multiple rounds of intensive logging are often assumed to be of little conservation value; consequently, there has been no concerted effort to prevent them from being converted to oil palm. However, no study has quantified the biodiversity of repeatedly logged forests. We compare the species richness and composition of birds and dung beetles within unlogged (primary), once-logged and twice-logged forests in Sabah, Borneo. Logging had little effect on the overall richness of birds. Dung beetle richness declined following once-logging but did not decline further after twice-logging. The species composition of bird and dung beetle communities was altered, particularly after the second logging rotation, but globally imperiled bird species (IUCN Red List) did not decline further after twice-logging. Remarkably, over 75 per cent of bird and dung beetle species found in unlogged forest persisted within twice-logged forest. Although twice-logged forests have less biological value than primary and once-logged forests, they clearly provide important habitat for numerous bird and dung beetle species. Preventing these degraded forests from being converted to oil palm should be a priority of policy-makers and conservationists.
  19. Fulltext Diversity and host associations of Myrsidea chewing lice (Phthiraptera: Menoponidae) in the tropical rainforest of Malaysian Borneo
    Madrid RS, Sychra O, Benedick S, Edwards DP, Efeykin BD, Fandrem M, et al.
    Int J Parasitol Parasites Wildl, 2020 Dec;13:231-247.
    PMID: 33294362 DOI: 10.1016/j.ijppaw.2020.10.011
    The tropical rainforests of Sundaland are a global biodiversity hotspot increasingly threatened by human activities. While parasitic insects are an important component of the ecosystem, their diversity and parasite-host relations are poorly understood in the tropics. We investigated parasites of passerine birds, the chewing lice of the speciose genus MyrsideaWaterston, 1915 (Phthiraptera: Menoponidae) in a natural rainforest community of Malaysian Borneo. Based on morphology, we registered 10 species of lice from 14 bird species of six different host families. This indicated a high degree of host specificity and that the complexity of the system could be underestimated with the potential for cryptic lineages/species to be present. We tested the species boundaries by combining morphological, genetic and host speciation diversity. The phylogenetic relationships of lice were investigated by analyzing the partial mitochondrial cytochrome oxidase I (COI) and the nuclear elongation factor alpha (EF-1α) genes sequences of the species. This revealed a monophyletic group of Myrsidea lineages from seven hosts of the avian family Pycnonotidae, one host of Timaliidae and one host of Pellorneidae. However, species delimitation methods supported the species boundaries hypothesized by morphological studies and confirmed that four species of Myrsidea are not single host specific. Cophylogenetic analysis by both distance-based test ParaFit and event-based method Jane confirmed overall congruence between the phylogenies of Myrsidea and their hosts. In total we recorded three cospeciation events for 14 host-parasite associations. However only one host-parasite link (M. carmenae and their hosts Terpsiphone affinis and Hypothymis azurea) was significant after the multiple testing correction in ParaFit. Four new species are described: Myrsidea carmenaesp.n. ex Hypothymis azurea and Terpsiphone affinis, Myrsidea franciscaesp.n. ex Rhipidura javanica, Myrsidea ramonisp.n. ex Copsychus malabaricus stricklandii, and Myrsidea victoriaesp.n. ex. Turdinus sepiarius.
  20. Quaternary land bridges have not been universal conduits of gene flow
    Cros E, Chattopadhyay B, Garg KM, Ng NSR, Tomassi S, Benedick S, et al.
    Mol Ecol, 2020 07;29(14):2692-2706.
    PMID: 32542783 DOI: 10.1111/mec.15509
    Quaternary climate oscillations are a well-known driver of animal diversification, but their effects are most well studied in areas where glaciations lead to habitat fragmentation. In large areas of the planet, however, glaciations have had the opposite effect, but here their impacts are much less well understood. This is especially true in Southeast Asia, where cyclical changes in land distribution have generated enormous land expansions during glacial periods. In this study, we selected a panel of five songbird species complexes covering a range of ecological specificities to investigate the effects Quaternary land bridges have had on the connectivity of Southeast Asian forest biota. Specifically, we combined morphological and bioacoustic analysis with an arsenal of population genomic and modelling approaches applied to thousands of genome-wide DNA markers across a total of more than 100 individuals. Our analyses show that species dependent on forest understorey exhibit deep differentiation between Borneo and western Sundaland, with no evidence of gene flow during the land bridges accompanying the last 1-2 ice ages. In contrast, dispersive canopy species and habitat generalists have experienced more recent gene flow. Our results argue that there remains much cryptic species-level diversity to be discovered in Southeast Asia even in well-known animal groups such as birds, especially in nondispersive forest understorey inhabitants. We also demonstrate that Quaternary land bridges have not been equally suitable conduits of gene flow for all species complexes and that life history is a major factor in predicting relative population divergence time across Quaternary climate fluctuations.
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