Niche theory suggests that sympatric species reduce interspecific competition through segregation of shared resources by adopting different attack manoeuvres. However, the fact that flycatcher-like bird species exclusively use the sally manoeuvre may thus challenge this view. We studied the foraging ecology of three flycatcher-like species (i.e. Paradise-flycatcher Terpsiphone sp., Black-naped Monarch Hypothymis azurea, and Rufous-winged Philentoma Philentoma pyrhoptera) in the Krau Wildlife Reserve in central Peninsular Malaysia. We investigated foraging preferences of each bird species and the potential niche partitioning via spatial or behavioural segregation. Foraging substrate was important parameter that effectively divided paradise-flycatcher from Black-naped Monarch and Rufous-winged Philentoma, where monarch and philentoma foraged mainly on live green leaves, while paradise-flycatcher foraged on the air. They also exhibited different foraging height preferences. Paradise-flycatcher, for instance, preferred the highest studied strata, while Black-naped Monarch foraged mostly in lower strata, and Rufous-winged Philentoma made use of the lowest strata. This study indicates that niche segregation occurs among sympatric species through foraging substrate and attack manoeuvres selection.
Tropical rainforests are considered as hotspots for bird diversity, yet little is known about the system that upholds the coexistence of species. Differences in body size that are associated with foraging strategies and spatial distribution are believed to promote the coexistence of closely related species by reducing competition. However, the fact that many babbler species do not differ significantly in their morphology has challenged this view. We studied the foraging ecology of nine sympatric babbler species (i.e., Pellorneum capistratum, P. bicolor, P. malaccense, Malacopteron cinereum, M. magnum, Stachyris nigriceps, S. nigricollis, S. maculata, and Cyanoderma erythropterum) in the Krau Wildlife Reserve in Peninsular Malaysia. We investigated; i) how these babblers forage in the wild and use vegetation to obtain food, and ii) how these trophically similar species differ in spatial distribution and foraging tactics. Results indicated that most babblers foraged predominantly on aerial leaf litter and used gleaning manoeuvre in intermediate-density foliage but exhibited wide ranges of vertical strata usage, thus reducing interspecific competition. The principal component analysis indicated that two components, i.e., foraging height and substrate are important as mechanisms to allow the coexistence of sympatric babblers. The present findings revealed that these bird species have unique foraging niches that are distinct from each other, and this may apply to other insectivorous birds inhabiting tropical forests. This suggests that niche separation does occur among coexisting birds, thus following Gause' law of competitive exclusion, which states two species occupying the same niche will not stably coexist.
Bird surveys were conducted in the Bukit Kepala Gajah limestone area in Lenggong, Perak from July 2010 to January 2011. The study area was divided into three zones: forest edge, forest intermediate and forest interior. A point-count distance sampling method was used in the bird surveys. The study recorded 7789 detections, representing 100 bird species belonging to 28 families. Pycnonotidae, Timaliidae and Nectariniidae were the dominant families overall and showed the highest number of observations recorded in the study area whereas Motacillidae showed the fewest observations. The bird species were grouped into three feeding guilds: insectivores, frugivores and others (omnivores, carnivores, nectarivores and granivores). The species richness of insectivorous birds differed significantly among the forest zones sampled (Kruskal-Wallis: α=0.05, H=10.979, d.f.=2, p=0.004), with more insectivorous birds occurring in the forest interior. No significant differences were found among the zones in the species richness of either the frugivore guild or the composite others guild.
Mixed-species flocks (MSFs) serve important roles in bird communities, especially in tropical forests. Although structure of mixed-species bird flocks and its benefits has been intensively studied globally, the foraging plasticity of a species when joining MSFs has rarely been evaluated. The present study examines foraging strategies of the Rufous-crowned Babbler (Malacopteron magnum), Chestnut-winged Babbler (Cyanoderma erythropterum) and Black-naped Monarch (Hypothymis azurea) when participating in MSFs in the Krau Wildlife Reserve, central Peninsular Malaysia. These species exhibit active foraging shifts in utilisation of vertical strata, foraging substrate, attack manoeuvres and foliage density, when foraging in MSFs, compared to when foraging outside MSFs. While the Rufous-crowned Babbler and Chestnut-winged Babbler commonly used gleaning and stretching (to completely extend the legs or neck to reach the food items) manoeuvres when foraging outside MSFs, respectively, they adopted probing manoeuvre and frequently used higher strata upon joining MSFs. The Chestnut-winged Babbler tended to forage on the underside of leaves and the Black-naped Monarch frequently utilised branches when joining MSFs, while they exclusively used aerial leaf litter and live green leaves, respectively, when foraging with conspecifics. The monarch also adopted the hovering manoeuvre and frequently foraged within denser foliage cover when joining MSFs. This study demonstrated that flock members exhibits foraging plasticity either through an expansion or active shift in foraging niches when participating in MSFs, thus suggesting the occurrence of possible foraging improvement and/or reductions in predation risk.
Bird surveys were conducted in the Padawan Limestone Area for seven days at each of two study sites, Giam and Danu, from August to December 2008. The purpose of the study was to compare the area's bird species richness and abundance of bird species in other limestone areas and in other forest types. The study also compared the species richness and relative abundance of birds in undisturbed and disturbed areas at both study sites. Twenty mist nets were deployed for 12 hours daily. During this study period, direct observations of birds were also made. In all, 80 species from 34 families were recorded at both sites. At Giam, 120 birds were mist-netted. These birds represented 31 species from 16 families. The direct observations at Giam recorded 13 species from 11 families. In the undisturbed area, 21 species from 13 families were mist-netted, whereas in the disturbed area, 21 species from 10 families were mist-netted. In Danu, a total of 48 birds, representing 25 species from 12 families, were mist-netted. The observations at Danu recorded 34 species from 19 families. Twelve species from 7 families were mist-netted in the undisturbed area, whereas 18 species from 11 families were mist-netted in the disturbed area. Statistical analysis showed that the species diversity index differed significantly between undisturbed and disturbed areas.
With the rapid growth of agricultural areas globally, forest birds increasingly encounter fragmented landscapes in which forest patches are surrounded by an agricultural plantation matrix, yet how birds respond behaviourally to this fragmentation is poorly understood. Information on microhabitat requirements of birds is scarce, but nevertheless essential to predicting adaptation of bird species to the patchy landscapes. We investigated foraging patterns of three tropical insectivorous birds, Green Iora Aegithina viridissima, Pin-striped Tit-Babbler Macronus gularis and Chestnut-winged Babbler Cyanoderma erythropterum, to determine whether they vary in foraging methods in different forest patches. Our study area encompassed old-logged lowland forest; one continuous forest and three forest patches. Observations were performed for 15 days every month for a period of 13 months. Information on foraging height, substrate, attack manoeuvres, and foliage density was collected independently for each foraging bird individual. All three species used different foraging substrates and attack manoeuvres in different habitat types. The Green Iora frequently used lower strata when foraging in forest patches as opposed to continuous forest, while the Pin-striped Tit-Babbler tended to forage in more dense vegetation in patches. Only Chestnut-winged Babbler displayed complete foraging plasticity across all study parameters. Different habitat features (e.g., edges, microclimates) between continuous forest and forest patches significantly influenced the foraging strategies of the study species. These changes in foraging strategies suggest that some Malaysian forest birds (e.g. generalist species) can respond behaviourally to fragmentation and habitat loss. Although continuous forest has critically important characteristics that need to be conserved, remnant forest patches are also important as ecological movement corridors and foraging grounds for birds.
The environmental crisis, due to the rapid growth of the world population and globalisation, is a serious concern of this century. Nanoscience and nanotechnology play an important role in addressing a wide range of environmental issues with innovative and successful solutions. Identification and control of emerging chemical contaminants have received substantial interest in recent years. As a result, there is a need for reliable and rapid analytical tools capable of performing sample analysis with high sensitivity, broad selectivity, desired stability, and minimal sample handling for the detection, degradation, and removal of hazardous contaminants. In this review, various gold-carbon nanocomposites-based sensors/biosensors that have been developed thus far are explored. The electrochemical platforms, synthesis, diverse applications, and effective monitoring of environmental pollutants are investigated comparatively.
Solar thermal energy storage (TES) is an outstanding innovation that can help solar technology remain relevant during nighttime and cloudy days. TES using phase change material (PCM) is an avant-garde solution for a clean and renewable energy transition. The present study unveils the unique potential of MXene as a performance enhancer in lauric acid (LA), which functions as a base PCM. The addition of graphene nanoplatelet (GNP) into the LA-MXene composite is prepared to comprehend and evaluate the benefits and detriments of adding carbon-based nanomaterial into the PCM via a two-step homogenizing method. A similar weight percentage of MXene and GNP at 0.75 was used for composite synthesis. The study found that the enthalpy of LA-MXene is comparable to LA at 169.87 J/kg and greater than LA-MXene/GNP, which has 137.53 J/kg. Regarding thermal storage performance, LA-MXene exhibited outstanding performance compared to LA-MXene/GNP in terms of enthalpy efficiency (λ) and relative enthalpy efficiency (η), achieving 95.4% and 96.1%, respectively. This is supported by the XPS spectra, which show that the crosslinking structure acted as a barrier, reinforcing the material and preventing further thermal degradation. This has resulted in robust and denser shells that significantly improved light absorption, enhancing both the photothermal conversion and thermal energy storage efficiency of LA/MXene. The present study reveals that LA-MXene is a promising and optimal candidate for the feasibility and reliability of TES in solar renewable energy applications. It was observed that the incorporation of exclusive MXene may effectively address the limitations of LA as a conventional PCM and surpass the traditional role of GNP. This study offers valuable insights into the superior performance of MXene alone, eliminating the need for doping with various nanomaterials and thereby reducing the complexity in synthesizing the PCM.
Magnetic Induction Tomography (MIT), which is also known as Electromagnetic Tomography (EMT) or Mutual Inductance Tomography, is among the imaging modalities of interest to many researchers around the world. This noninvasive modality applies an electromagnetic field and is sensitive to all three passive electromagnetic properties of a material that are conductivity, permittivity and permeability. MIT is categorized under the passive imaging family with an electrodeless technique through the use of excitation coils to induce an electromagnetic field in the material, which is then measured at the receiving side by sensors. The aim of this review is to discuss the challenges of the MIT technique and summarize the recent advancements in the transmitters and sensors, with a focus on applications in biological tissue imaging. It is hoped that this review will provide some valuable information on the MIT for those who have interest in this modality. The need of this knowledge may speed up the process of adopted of MIT as a medical imaging technology.
Simulium asakoae Takaoka and Davies has been confirmed to bite humans and has been incriminated as a vector of blood protozoan parasites of the genera Leucocytozoon and Trypanosoma, as well as an unknown filarial parasite in Thailand. However, its attraction to humans has remained uninvestigated in Malaysia. Recently, 27 black flies were collected in Pahang, Malaysia, of which 25 were captured in CO2-baited Malaise traps and two were collected from humans during trapping activity. All specimens were morphologically identified as S. asakoae. Cytochrome c oxidase I sequences of the two specimens caught on humans showed 100% similarity with those of S. asakoae in the NCBI GenBank, confirming their morphological identity. Blood-meal analysis using a HAL·HARTM kit did not show the presence of domestic or wild animal DNA. However, human DNA was amplified from one engorged fly in the cytochrome b gene amplification assay, providing the first evidence of blood-feeding by S. asakoae in Malaysia.
Neoschoengastia gallinarum is widely distributed in Asia, preferentially parasitising birds, and heavy infestations have clinical impacts on domestic fowl. In common with other trombiculid mites, the genetic diversity and potential variation in host preferences or pathology induced by N. gallinarum are poorly understood. This study aimed to unravel the geographical variation and population structure of N. gallinarum collected from galliform birds in Peninsular Malaysia and Thailand by inference from concatenated mitochondrial-encoded cytochrome c oxidase subunit I (COI), and nuclear-encoded internal transcribed spacer 2 (ITS2) and 18S ribosomal DNA gene sequences, including a comparison with previously published data from southeastern China. Our multi-locus sequence analysis revealed three monophyletic clades comprising (A) specimens from Peninsular Malaysia, (B) the samples from Thailand together with a minority of Chinese sequences, and (C) the majority of sequences from China. Similarly, most species delimitation approaches divided the specimens into three operational taxonomic units. Analysis of molecular variance revealed 96.41% genetic divergence between Malaysian and Thai populations, further supported by the absence of gene flow (Nm = 0.01). In conclusion, despite the two countries sharing a land border, populations of N. gallinarum from Peninsular Malaysia and Thailand appear to be genetically segregated and may represent distinct cryptic species.