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Multifaceted interactions between the pseudomonads and insects: mechanisms and prospects

Teoh MC, Furusawa G, Veera Singham G

Arch Microbiol, 2021 Jul;203(5):1891-1915.
PMID: 33634321 DOI: 10.1007/s00203-021-02230-9

Insects and bacteria are the most widespread groups of organisms found in nearly all habitats on earth, establishing diverse interactions that encompass the entire range of possible symbiotic associations from strict parasitism to obligate mutualism. The complexity of their interactions is instrumental in shaping the roles of insects in the environment, meanwhile ensuring the survival and persistence of the associated bacteria. This review aims to provide detailed insight on the multifaceted symbiosis between one of the most versatile bacterial genera, Pseudomonas (Gammaproteobacteria: Pseudomonadaceae) and a diverse group of insect species. The Pseudomonas engages with varied interactions with insects, being either a pathogen or beneficial endosymbiont, as well as using insects as vectors. In addition, this review also provides updates on existing and potential applications of Pseudomonas and their numerous insecticidal metabolites as biocontrol agents against pest insects for the improvement of integrated pest management strategies. Here, we have summarized several known modes of action and the virulence factors of entomopathogenic Pseudomonas strains essential for their pathogenicity against insects. Meanwhile, the beneficial interactions between pseudomonads and insects are currently limited to a few known insect taxa, despite numerous studies reporting identification of pseudomonads in the guts and haemocoel of various insect species. The vector-symbiont association between pseudomonads and insects can be diverse from strict phoresy to a role switch from commensalism to parasitism following a dose-dependent response. Overall, the pseudomonads appeared to have evolved independently to be either exclusively pathogenic or beneficial towards insects.

Matched MeSH terms: Insects/classification; Insects/microbiology*
An overview of antifungal peptides derived from insect

Faruck MO, Yusof F, Chowdhury S

Peptides, 2016 06;80:80-88.
PMID: 26093218 DOI: 10.1016/j.peptides.2015.06.001

Fungi are not classified as plants or animals. They resemble plants in many ways but do not produce chlorophyll or make their own food photosynthetically like plants. Fungi are useful for the production of beer, bread, medicine, etc. More complex than viruses or bacteria; fungi can be destructive human pathogens responsible for various diseases in humans. Most people have a strong natural immunity against fungal infection. However, fungi can cause diseases when this immunity breaks down. In the last few years, fungal infection has increased strikingly and has been accompanied by a rise in the number of deaths of cancer patients, transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients owing to fungal infections. The growth rate of fungi is very slow and quite difficult to identify. A series of molecules with antifungal activity against different strains of fungi have been found in insects, which can be of great importance to tackle human diseases. Insects secrete such compounds, which can be peptides, as a part of their immune defense reactions. Active antifungal peptides developed by insects to rapidly eliminate infectious pathogens are considered a component of the defense munitions. This review focuses on naturally occurring antifungal peptides from insects and their challenges to be used as armaments against human diseases.

Matched MeSH terms: Insects/metabolism; Insects/microbiology
Defining and measuring trophic role similarity in food webs using regular equivalence

Luczkovich JJ, Borgatti SP, Johnson JC, Everett MG

J Theor Biol, 2003 Feb 07;220(3):303-21.
PMID: 12468282

We present a graph theoretic model of analysing food web structure called regular equivalence. Regular equivalence is a method for partitioning the species in a food web into "isotrophic classes" that play the same structural roles, even if they are not directly consuming the same prey or if they do not share the same predators. We contrast regular equivalence models, in which two species are members of the same trophic group if they have trophic links to the same set of other trophic groups, with structural equivalence models, in which species are equivalent if they are connected to the exact same other species. Here, the regular equivalence approach is applied to two published food webs: (1) a topological web (Malaysian pitcher plant insect food web) and (2) a carbon-flow web (St. Marks, Florida seagrass ecosystem food web). Regular equivalence produced a more satisfactory set of classes than did the structural approach, grouping basal taxa with other basal taxa and not with top predators. Regular equivalence models provide a way to mathematically formalize trophic position, trophic group and trophic niche. These models are part of a family of models that includes structural models used extensively by ecologists now. Regular equivalence models uncover similarities in trophic roles at a higher level of organization than do the structural models. The approach outlined is useful for measuring the trophic roles of species in food web models, measuring similarity in trophic relations of two or more species, comparing food webs over time and across geographic regions, and aggregating taxa into trophic groups that reduce the complexity of ecosystem feeding relations without obscuring network relationships. In addition, we hope the approach will prove useful in predicting the outcome of predator-prey interactions in experimental studies.

Matched MeSH terms: Insects
CRISPR-Cas9 Genome Editing Tool for the Production of Industrial Biopharmaceuticals

Khan AH, Tye GJ, Noordin R

Mol Biotechnol, 2020 Sep;62(9):401-411.
PMID: 32749657 DOI: 10.1007/s12033-020-00265-9

A broad range of cell lines with characteristic features are used as bio-factories to produce recombinant proteins for basic research and therapeutic purposes. Genetic engineering strategies have been used to manipulate the genome of mammalian cells, insects, and yeasts for heterologous expression. One reason is that the glycosylation pattern of the expression hosts differs somehow from mammalian cells, which may cause immunogenic reactions upon administration in humans. CRISPR-Cas9 is a simple, efficient, and versatile genome engineering tool that can be programmed to precisely make double-stranded breaks at the desired loci. Compared to the classical genome editing methods, a CRISPR-Cas9 system is an ideal tool, providing the opportunity to integrate or delete genes from the target organisms. Besides broadened applications, limited studies have used CRISPR-Cas9 for editing the endogenous pathways in expression systems for biopharmaceutical applications. In the present review, we discuss the use of CRISPR-Cas9 in expression systems to improve host cell lines, increase product yield, and humanize glycosylation pathways by targeting intrinsic genes.

Matched MeSH terms: Insects
Fulltext The used of recombinant plasmid DNA in GMO quantitative analysis of insect resistance maize targeted unapproved StarLink corn and approved Bt176 corn in food and feed sold commercially sold Malaysia

International Food Research Journal, 2011;18(1):167-178.
MyJurnal

Genetically modified organisms (GMO) are increased remarkably from year to year and the estimated global area cultivated with genetically modified (GM) crops reached 125 million hectares in year 2008. However, insect resistance maize based on Bacillus thuringienses (Bt) is of the most cultivated GM crop in worldwide. Bacillus thuringiensis (Bt) is an aerobic, gram-positive bacterium that synthesize one or more Cry protein that are toxic to various types crop and forestry insects pests. To date, several cry genes have been introduced into GM plant to combat with various type of insect. Worldwide commercialization of GM crops has raised the customers’ concern about the Biosafety issues, and thus, many countries have implemented the labeling legislations for GM food and their derivatives. In this study, we introduced the quantitative analysis method based on the recombinant plasmid DNA as calibrators that can be used to determine the percentage of GMO content in various types of food and feed samples. Therefore, we have reported 7.5% (6/80) of the samples were contained StarLink maize and 1.25% (1/80) samples were contained Bt176 maize. Additionally, the percentage of GM content in each positive sample were further determined with the developed quantitative method. The percentage of the StarLink corns that present in the positive samples were varies from 0.09% to 2.53% and Bt176 corn that present in the positive sample was 16.90%. The present study demonstrated that the recombinant plasmid DNA that used in quantitative real-time method as good alternative quantitative analysis of GM content.

Matched MeSH terms: Insects
Fulltext Bacillus thuringiensis parasporal proteins and their effect on human cancer cells: an overview

Wong, Rebecca Shin Yee

International e-Journal of Science, Medicine & Education, 2010;4(2):-.
MyJurnal

Bacillus thuringiensis is an anaerobic, spore forming bacterium that produces various toxic proteins both during its vegetative stage and sporulative stage. During its sporulative stage, it produces parasporal proteins that have long been used in the agriculture fields as insecticides. Although anticancer effect of Bacillus thuringiensis parasporal proteins can be dated back to the 1970s, research in this area went through a giant leap in the late 1990s, with much of the work being done in Japan. It has been found that some strains of non-insecticidal Bacillus thuringiensis produce parasporal proteins that exhibit anticancer activity. Due to their selectivity against human cancer cells but not normal cells, some of these proteins have been extensively studied for their anticancer effect and the mechanism of action by which these proteins kill cancer cells have also been widely explored in Japan and Malaysia with sporadic reports from other parts of the world. The abundance of these bacilli in nature and their selectivity have made them potential candidates for cancer treatment. However, literature on the in vivo effect of these proteins is scarce. Since different Bacillus thuringiensis strains produce different cytotoxic proteins with wide variations in their anticancer effect and mechanism of action, further investigations are necessary and their effect in vivo must be well established before they can be used in human subjects.

Matched MeSH terms: Insects
Fulltext Seed morphology variation of rice landraces from Tuaran and Kota Belud districts of Sabah, Malaysia

CHEE, F. T., SIAMBUN, M. M., MARIAM A. L.

Buletin Persatuan Genetik Malaysia, 2011;18(1):10-16.
MyJurnal

There is a need to set up a germplasm resource centre or gene bank in Sabah to keep the collections of varieties of locally cultivated crops, especially rice. This is necessary to prevent genetic loss caused by the infrastructure development in the state of Sabah especially when Sabah is known for her rich genetic resources for food and agriculture. This gene bank will play an important role in the conservation of genetic resources especially for future rice crop improvement and development. These collections are known to carry useful gene(s) for crop improvement such as aroma, taste, resistance to insect pests and diseases, and tolerance to abiotic stress. Decades ago, a set of local landrace rice collection were made and conserved at International Rice Research Institute (IRRI) and Malaysia Agriculture Research and Development Institute (MARDI). Besides IRRI and MARDI, local farmers also play an important role as conservationist. Therefore, this study has been carried out to re ne the status of the current genetic diversity in local rice farming. From January 2009 to February 2010, 108 samples were collected from Tuaran and Kota Belud districts. Preliminary observation of 19 samples found that
there is a high genetic diversity based on seed morphology alone. Variations in the characteristics were detected in awn, apiculus, lemma and palea, sterile lemma and seed coat. Length and width of seeds were measured and calculated for ratio to estimate the shapes of the seeds. The weight of 100 grains ranged from 1.42 to 3.19 g. However, further studies on morphology evaluation, disease screening, and molecular evaluation are needed to be compared with the existing data. In addition, genetic erosion, migration, and drift also need to be studied due to high seed exchanges among the local farmers.

Matched MeSH terms: Insects
Fulltext Suppression subtractive hybridization technique in wheat for the identification of disease resistance differentially expressed genes

Aktar-Uz-Zamana, Md., Tuhina-Khatun, Mst., Mohamed Hanafi Musa, Sahebi, Mahbod

The Pertanika Journal of Scholarly Research Reviews, 2015;2(1):49-62.
MyJurnal

A resistant variety with high yielding potential is key for increasing crop production to
fulfill the food requirement of the ever increasing world populations. Consequently, the aim of plant
breeders is to develop high yielding varieties or cultivars that are resistant or tolerant to specific
diseases or insects. For developing a resistant variety, it is enormously indispensable to incorporate or
introgress the specific resistant genes of that particular disease into the recipient. Suppression
subtractive hybridization (SSH) is a powerful technique for the identification of disease specific
differentially expressed genes that are expressed in a resistant or susceptible variety. This paper
presents a brief review on the SSH technique with examples focusing on the identification of the
wheat disease specific differentially expressed genes and their defense mechanisms against fungal
pathogens in global wheat cultivars. This review is helpful for wheat researchers for the updated
information on the SSH technique for the identification of differentially expressed genes in the global
wheat cultivars and varieties. Eventually, the identified genes could be used to develop the disease
resistance variety through marker-assisted backcrossing programme or conventional breeding.

Matched MeSH terms: Insects
Ensemble-based, high-throughput virtual screening of potential inhibitor targeting putative farnesol dehydrogenase of Metisa plana (Lepidoptera: Psychidae)

Zifruddin AN, Mohamad Yusoff MA, Abd Ghani NS, Nor Muhammad NA, Lam KW, Hassan M

Comput Biol Chem, 2023 Apr;103:107811.
PMID: 36645937 DOI: 10.1016/j.compbiolchem.2023.107811

Metisa plana (Lepidoptera: Psychidae) bagworm is a leaf-eater caterpillar ubiquitously found as a damaging pest in oil palm plantations, specifically in Malaysia. Various strategies have been implemented, including the usage of chemical insecticides. However, the main challenges include the development of insecticide resistance and its detrimental effects on the environment and non-target organisms. Therefore, a biorational insecticide is introduced by targeting the juvenile hormone (JH) biosynthetic pathway, which is mainly present in the insect and vital for the insect's growth, diapause, metamorphosis, and adult reproduction. This study aimed to investigate the potential inhibitor for the rate-limiting enzyme involved in the JH pathway known as farnesol dehydrogenase. A 255 amino acids sequence encoded for the putative M. plana farnesol dehydrogenase (MpFolDH) open reading frame had been identified and isolated. The three-dimensional structure of MpFolDH was predicted to have seven β- sheets with α-helices at both sides, showing typical characteristics for classical short-chain dehydrogenase and associated with oxidoreductase activity. Then, the ensemble-based virtual screening was conducted based on the ZINC20 database, in which 43 768 compounds that fulfilled pesticide-likeness criteria were screened by site-specific molecular docking. After a short molecular dynamics simulation (5 ns) was conducted towards 102 compounds, only the top 10 compounds based on their most favourable binding energy were selected for a more extended simulation (100 ns). Based on the protein-ligand stability, protein compactness, residues rigidity, binding interaction, binding energy throughout the 100 ns simulation, and physicochemical analysis, ZINC000408743205 was selected as a potential inhibitor for this enzyme. Amino acids decomposition analysis indicates Ile18, Ala95, Val198 and Val202 were the critical contributor residues for MpFolDH-inhibitors(s) complex.

Matched MeSH terms: Insects
Reporting beetles in a mummified human corpse in Malaysia: Necrobia rufipes (Fabricius, 1781) (Coleoptera: Cleridae) and Dermestes maculatus De Geer, 1774 (Coleoptera: Dermestidae)

Ivorra T, Rahimi R, Zaini NA, Heo CC

Leg Med (Tokyo), 2023 May;62:102238.
PMID: 36913819 DOI: 10.1016/j.legalmed.2023.102238

This case study reports on two unrecorded Coleopteran species found together on a human corpse in Malaysia. The mummified human remains were discovered in a house in Selangor, Malaysia. The pathologist confirmed that the death was due to a traumatic chest injury. Maggots, beetles, and fly pupal casings were found mainly on the front part of the body. Empty puparia of Diptera were collected during the autopsy and identified later as the muscid Synthesiomyia nudiseta (van der Wulp, 1883) (Diptera: Muscidae). Also, the insect evidence received included larvae and pupae of Megaselia sp. (Diptera: Phoridae). According to the insect development data, the minimum postmortem period was estimated by the time to reach the pupal developmental stage (in days). The entomological evidence included the first record of Dermestes maculatus De Geer, 1774 (Coleoptera: Dermestidae) and Necrobia rufipes (Fabricius, 1781) (Coleoptera: Cleridae), which have not previously been recorded on human remains in Malaysia.

Matched MeSH terms: Insects
Fulltext Understanding vegetable farmers' adoption, dis-adoption, and non-adoption decisions of pest management by pheromone trapping

Kabir MH, Nur-E-Alam SM, Datta A, Tan ML, Rahman MS

PLoS One, 2023;18(9):e0292254.
PMID: 37773932 DOI: 10.1371/journal.pone.0292254

The use of pheromone traps can minimize the excess application of synthetic insecticides, while can also benefit the environment. The use of pheromone traps has been promoted and suggested to vegetable farmers of Bangladesh for widespread adoption. However, the majority of farmers have continued to spray insecticides instead of using pheromone traps. The present study investigated the factors influencing farmers' adoption, dis-adoption, and non-adoption behavior of pheromone traps for managing insect pests. Primary data were collected from 438 vegetable growers. Data were analyzed using descriptive statistics and multinomial logistic regression. About 27% of the farmers abandoned the technique shortly after it was adopted as it was time-consuming to manage insect pests. Marginal effect analysis revealed that the likelihood of continued adoption was 34.6% higher for farmers who perceived that pheromone traps were useful in controlling insect pests. In contrast, the likelihood of dis-adoption was 16.5% and 10.4% higher for farmers who maintained communication with private pesticide company agents and neighbor farmers, respectively. Extension services by government extension personnel might be encouraged and maintained as a key component in increasing farmer awareness regarding the use of pheromone trap. Strategies to promote pheromone traps in vegetable production should highlight the positive impacts to farmers and the environment, as this would most likely lead to their continued and widespread use after initial adoption.

Matched MeSH terms: Insects
Fulltext Ecological importance of sedges: a survey of the Australasian Cyperaceae genus Lepidosperma

Barrett RL

Ann Bot, 2013 Apr;111(4):499-529.
PMID: 23378523 DOI: 10.1093/aob/mct008

BACKGROUND: Sedges (Cyperaceae) form an important ecological component of many ecosystems around the world. Sword and rapier sedges (genus Lepidosperma) are common and widespread components of the southern Australian and New Zealand floras, also occurring in New Caledonia, West Papua, Borneo, Malaysia and southern China. Sedge ecology is seldom studied and no comprehensive review of sedge ecology exists. Lepidosperma is unusual in the Cyperaceae with the majority of species occurring in dryland habitats.
SCOPE: Extensive review of ecological literature and field observations shows Lepidosperma species to be important components of many ecosystems, often dominating understorey and sedge-rich communities. For the first time, a detailed ecological review of a Cyperaceae genus is presented.
CONCLUSIONS: Lepidosperma species are long-lived perennials with significant abundance and persistence in the landscape. Speciation patterns in the genus are of considerable interest due to complex biogeographical patterns and a high degree of habitat specificity. Potential benefits exist for medicinal products identified from several Lepidosperma species. Over 178 organisms, including 26 mammals, 42 birds, six reptiles, five amphibians, eight arachnids, 75 insects, three crustaceans and 13 fungi, are found to be dependent on, or making use of, Lepidosperma species. A significant relationship exists between Lepidosperma species and the moth genus Elachista. Implications for the conservation and ecology of both sedges and associated species are discussed.

Matched MeSH terms: Insects
Fatty acid profile, minor bioactive constituents and physicochemical properties of insect-based oils: A comprehensive review

Yap JW, Lee YY, Tang TK, Chong LC, Kuan CH, Lai OM, et al.

Crit Rev Food Sci Nutr, 2023;63(21):5231-5246.
PMID: 34913758 DOI: 10.1080/10408398.2021.2015681

Insect-based food or ingredients have received tremendous attention worldwide because of their potential to ensure food and nutrition security, mitigating the reliance on land-dependent agricultural products. Indeed, insect-farming has low environmental impacts with reduced land, water and energy input. More importantly, insects are rich in high quality proteins and fats. They are also excellent sources of minerals, vitamins and bioactive compounds. Insect-based lipids are intriguing because they may contain high levels of unsaturated fatty acids particularly linoleic and α-linolenic acids. Besides, the insect-based lipids also show a considerable amount of bioactive components such as tocols, sterols and carotenoids. However, their fatty acid compositions and the nutritional values may vary depending on species, feed composition, developmental stage, geographical locations, and extraction techniques. Therefore, the present article aims to provide a comprehensive review on the fatty acid composition, the minor bioactive constituents and the physicochemical properties of fats and oils derived from insects of different orders (Coleoptera, Lepidoptera, Hymenoptera, Orthoptera, Hemiptera and Diptera). The various parameters affecting the nutritional compositions of the insect-based lipids will also be highlighted. These information will definitely provide a detailed insight on the potential applications of these fats in various food systems based on their unique properties.

Matched MeSH terms: Insects
Fulltext Establishing the evidence base for maintaining biodiversity and ecosystem function in the oil palm landscapes of South East Asia

Foster WA, Snaddon JL, Turner EC, Fayle TM, Cockerill TD, Ellwood MD, et al.

Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3277-91.
PMID: 22006968 DOI: 10.1098/rstb.2011.0041

The conversion of natural forest to oil palm plantation is a major current threat to the conservation of biodiversity in South East Asia. Most animal taxa decrease in both species richness and abundance on conversion of forest to oil palm, and there is usually a severe loss of forest species. The extent of loss varies significantly across both different taxa and different microhabitats within the oil palm habitat. The principal driver of this loss in diversity is probably the biological and physical simplification of the habitat, but there is little direct evidence for this. The conservation of forest species requires the preservation of large reserves of intact forest, but we must not lose sight of the importance of conserving biodiversity and ecosystem processes within the oil palm habitat itself. We urgently need to carry out research that will establish whether maintaining diversity supports economically and ecologically important processes. There is some evidence that both landscape and local complexity can have positive impacts on biodiversity in the oil palm habitat. By intelligent manipulation of habitat complexity, it could be possible to enhance not only the number of species that can live in oil palm plantations but also their contribution to the healthy functioning of this exceptionally important and widespread landscape.

Matched MeSH terms: Insects/physiology
Fulltext An observation on the decomposition process of gasoline-ingested monkey carcasses in a secondary forest in Malaysia

Rumiza AR, Khairul O, Zuha RM, Heo CC

Trop Biomed, 2010 Dec;27(3):373-83.
PMID: 21399577

This study was designed to mimic homicide or suicide cases using gasoline. Six adult long-tailed macaque (Macaca fascicularis), weighing between 2.5 to 4.0 kg, were equally divided into control and test groups. The control group was sacrificed by a lethal dose of phenobarbital intracardiac while test group was force fed with two doses of gasoline LD50 (37.7 ml/kg) after sedation with phenobarbital. All carcasses were then placed in a decomposition site to observe the decomposition and invasion process of cadaveric fauna on the carcasses. A total of five decomposition stages were recognized during this study. This study was performed during July 2007. Fresh stage of control and test carcasses occurred between 0 to 15 and 0 to 39 hours of exposure, respectively. The subsequent decomposition stages also exhibited the similar pattern whereby the decomposition process of control carcasses were faster than tested one. The first larvae were found on control carcasses after 9 hours of death while the test group carcasses had only their first blowfly eggs after 15 hours of exposure. Blow flies, Achoetandrus rufifacies and Chrysomya megacephala were the most dominant invader of both carcasses throughout the decaying process. Diptera collected from control carcasses comprised of scuttle fly, Megaselia scalaris and flesh fly, sarcophagid. We concluded that the presence of gasoline and its odor on the carcass had delayed the arrival of insect to the carcasses, thereby slowing down the decomposition process in the carcass by 6 hours.

Matched MeSH terms: Insects/growth & development*
Fulltext Complete mitochondrial genome of Dacus vijaysegarani and phylogenetic relationships with congeners and other tephritid fruit flies (Insecta: Diptera)

Yong HS, Chua KO, Song SL, Liew YJ, Eamsobhana P, Chan KG

Mol Biol Rep, 2021 Aug;48(8):6047-6056.
PMID: 34357549 DOI: 10.1007/s11033-021-06608-2

BACKGROUND: Tephritid fruit flies of the genus Dacus are members of the tribe Dacini, subfamily Dacinae. There are some 274 species worldwide, distributed in Africa and the Asia-Pacific. To date, only five complete mitochondrial genomes (mitogenomes) of Dacus fruit flies have been published and are available in the GenBank.
METHODS AND RESULTS: In view of the lack of study on their mitogenome, we sequenced (by next generation sequencing) and annotated the complete mitogenome of D. vijaysegarani from Malaysia to determine its features and phylogenetic relationship. The whole mitogenome of D. vijaysegarani has identical gene order with the published mitogenomes of the genus Dacus, with 13 protein-coding genes, two rRNA genes, 22 tRNAs, a non-coding A + T rich control region, and intergenic spacer and overlap sequences. Phylogenetic analysis based on 15 mitochondrial genes (13 PCGs and two rRNA genes), reveals Dacus, Zeugodacus and Bactrocera forming a distinct clade. The genus Dacus forms a monophyletic group in the subclade containing also the Zeugodacus group; this Dacus-Zeugodacus subclade is distinct from the Bactrocera subclade. D. (Mellesis) vijaysegarani forms a lineage with D. (Mellesis) trimacula in the subcluster containing also the lineage of D. (Mellesis) conopsoides and D. (Callantra) longicornis. D. (Dacus) bivittatus and D. (Didacus) ciliatus form a distinct subcluster. Based on cox1 sequences, the Malaysia and Vietnam taxa of D. vijaysegarani may not be conspecific.
CONCLUSIONS: Overall, the mitochondrial genome of D. vijaysegarani provided essential molecular data that could be useful for further studies for species diagnosis, evolution and phylogeny research of other tephritid fruit flies in the future.

Matched MeSH terms: Insects/genetics
Diversity of pollination ecology in the Schismatoglottis Calyptrata Complex Clade (Araceae)

Hoe YC, Gibernau M, Wong SY

Plant Biol (Stuttg), 2018 May;20(3):563-578.
PMID: 29316090 DOI: 10.1111/plb.12687

Field studies integrating pollination investigations with an assessment of floral scent composition and thermogenesis in tropical aroids are rather few. Thus, this study aimed to investigate the pollination biology of nine species belonging to Schismatoglottis Calyptrata Complex Clade. The flowering mechanism, visiting insect activities, reproductive system, thermogenesis and floral scent composition were examined. Anthesis for all species started at dawn and lasted 25-29 h. Colocasiomyia (Diptera, Drosophilidae) are considered the main pollinators for all the investigated species. Cycreon (Coleoptera, Hydrophilidae) are considered secondary pollinators as they are only present in seven of the nine host plants, despite the fact that they are the most effective pollen carrier, carrying up to 15 times more pollen grains than Colocasiomyia flies. However, the number of Colocasiomyia individuals was six times higher than Cycreon beetles. Chaloenus (Chrysomelidae, Galeuricinae) appeared to be an inadvertent pollinator. Atheta (Coleoptera, Staphylinidae) is considered a floral visitor in most investigated species of the Calyptrata Complex Clade in Sarawak, but a possible pollinator in S. muluensis. Chironomidae midges and pteromalid wasps are considered visitors in S. calyptrata. Thermogenesis in a biphasic pattern was observed in inflorescences of S. adducta, S. calyptrata, S. giamensis, S. pseudoniahensis and S. roh. The first peak occurred during pistillate anthesis; the second peak during staminate anthesis. Inflorescences of all investigated species of Calyptrata Complex Clade emitted four types of ester compound, with methyl ester-3-methyl-3-butenoic acid as a single major VOC (volatile organic compound). The appendix, pistillate zone, staminate zone and spathe emitted all these compounds. A mixed fly-beetle pollination system is considered an ancestral trait in the Calyptrata Complex Clade, persisting in Sarawak taxa, whereas the marked reduction of interpistillar staminodes in taxa from Peninsular Malaysia and especially, Ambon, Indonesia, is probably linked to a shift in these taxa to a fly-pollinated system.

Matched MeSH terms: Insects/physiology
Fulltext Fungi and insects compensate for lost vertebrate seed predation in an experimentally defaunated tropical forest

Williams PJ, Ong RC, Brodie JF, Luskin MS

Nat Commun, 2021 Mar 12;12(1):1650.
PMID: 33712621 DOI: 10.1038/s41467-021-21978-8

Overhunting reduces important plant-animal interactions such as vertebrate seed dispersal and seed predation, thereby altering plant regeneration and even above-ground biomass. It remains unclear, however, if non-hunted species can compensate for lost vertebrates in defaunated ecosystems. We use a nested exclusion experiment to isolate the effects of different seed enemies in a Bornean rainforest. In four of five tree species, vertebrates kill many seeds (13-66%). Nonetheless, when large mammals are excluded, seed mortality from insects and fungi fully compensates for the lost vertebrate predation, such that defaunation has no effect on seedling establishment. The switch from seed predation by generalist vertebrates to specialist insects and fungi in defaunated systems may alter Janzen-Connell effects and density-dependence in plants. Previous work using simulation models to explore how lost seed dispersal will affect tree species composition and carbon storage may require reevaluation in the context of functional redundancy within complex species interactions networks.

Matched MeSH terms: Insects/physiology*
Fulltext Ecological impacts of tropical forest fragmentation: how consistent are patterns in species richness and nestedness?

Hill JK, Gray MA, Khen CV, Benedick S, Tawatao N, Hamer KC

Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3265-76.
PMID: 22006967 DOI: 10.1098/rstb.2011.0050

Large areas of tropical forest now exist as remnants scattered across agricultural landscapes, and so understanding the impacts of forest fragmentation is important for biodiversity conservation. We examined species richness and nestedness among tropical forest remnants in birds (meta-analysis of published studies) and insects (field data for fruit-feeding Lepidoptera (butterflies and moths) and ants). Species-area relationships were evident in all four taxa, and avian and insect assemblages in remnants typically were nested subsets of those in larger areas. Avian carnivores and nectarivores and predatory ants were more nested than other guilds, implying that the sequential loss of species was more predictable in these groups, and that fragmentation alters the trophic organization of communities. For butterflies, the ordering of fragments to achieve maximum nestedness was by fragment area, suggesting that differences among fragments were driven mainly by extinction. In contrast for moths, maximum nestedness was achieved by ordering species by wing length; species with longer wings (implying better dispersal) were more likely to occur at all sites, including low diversity sites, suggesting that differences among fragments were driven more strongly by colonization. Although all four taxa exhibited high levels of nestedness, patterns of species turnover were also idiosyncratic, and thus even species-poor sites contributed to landscape-scale biodiversity, particularly for insects.

Matched MeSH terms: Insects/physiology*
Fulltext Impacts of logging on density-dependent predation of dipterocarp seeds in a South East Asian rainforest

Bagchi R, Philipson CD, Slade EM, Hector A, Phillips S, Villanueva JF, et al.

Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3246-55.
PMID: 22006965 DOI: 10.1098/rstb.2011.0034

Much of the forest remaining in South East Asia has been selectively logged. The processes promoting species coexistence may be the key to the recovery and maintenance of diversity in these forests. One such process is the Janzen-Connell mechanism, where specialized natural enemies such as seed predators maintain diversity by inhibiting regeneration near conspecifics. In Neotropical forests, anthropogenic disturbance can disrupt the Janzen-Connell mechanism, but similar data are unavailable for South East Asia. We investigated the effects of conspecific density (two spatial scales) and distance from fruiting trees on seed and seedling survival of the canopy tree Parashorea malaanonan in unlogged and logged forests in Sabah, Malaysia. The production of mature seeds was higher in unlogged forest, perhaps because high adult densities facilitate pollination or satiate pre-dispersal predators. In both forest types, post-dispersal survival was reduced by small-scale (1 m(2)) conspecific density, but not by proximity to the nearest fruiting tree. Large-scale conspecific density (seeds per fruiting tree) reduced predation, probably by satiating predators. Higher seed production in unlogged forest, in combination with slightly higher survival, meant that recruitment was almost entirely limited to unlogged forest. Thus, while logging might not affect the Janzen-Connell mechanism at this site, it may influence the recruitment of particular species.

Matched MeSH terms: Insects/physiology

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