Histology and biogenic amines localization of salivary gland of the adult Red Palm Weevil, Rhynchophorus ferrugineus (coleoptera: dryophthoridae)

This study describes the histology and biogenic amines localization of salivary glands of the adult Red Palm Weevil (RPW), Rhynchophorus ferrugineus. The observation were done by using light microscopy of Zeiss Image Analyzer with Axio Vision software and Zeiss Axioscope with iSolutionlite software. The histology involves staining procedures of haematoxylin and eosin staining method while the immunohistochemistry analysis involves serotonin and dopamine of the biogenic amines. The salivary gland of the RPW adult is a single tubular gland. The single gland lies dorsally on the alimentary tract of the insect that begins in the head and extends through the thorax into the abdomen. The reservoir region is located in the mid to fore region of the gland, while the secretary region is found in the mid to rear part of the gland. The reservoir region of the RPW tubular gland seems to probably secrete only water and ions but do not secrete enzymes. The distribution of biogenic amines suggest that dopamine mainly stimulates the production of water-based saliva in the secretory cells of the reservoir region, while serotonin stimulates the production of protein-rich saliva in the secretory cells of the secretory region

Preliminary study of gut bacterial abundance in Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) fed on different diets

Rhynchophorus ferrugineus or also known as RPW is a major pest in many parts of the world and has infested coconut plantations in Malaysia especially in Terengganu and Kelantan. To date, a combination of many methods such as trapping with pheromone, chemical pesticide, and biological pesticide (Integrated Pest Management) were applied to control RPW infestation. However, IPM often could not be used as a method for total eradication and in addition to that, IPM necessitates continuous laborious effort. Thus, a new target for RPW eradication method with high specificity must be identified. The purpose of this research is to study the effect of different diets towards gut bacterial abundance in RPW and thus widen the knowledge regarding their correlation. Parameter measured were abundance of gut bacteria following different diets treatment. 16S rRNA amplicon sequencing method was used in this research to identify all gut bacteria present in the RPW. Our analysis showed that there are six most abundant group of bacteria with different phylogenetic group rank present in RPW’s gut. This include Enterobacteriaceae, Leminorella grimontii, Entomoplasmatales, Erysipelothrix, Lactobacillus and Leuconostoc. This groups of bacteria were known to have significant roles toward host’s gut such as aiding in digestion, synthesizing hormone, and protecting from pathogenic bacteria growth. Comprehensive data obtained from this study on these microbes have potential to be used in exploring new dimension of RPW pest management

Ultrastructure on the light organ of tropical synchronize firefly, Pteroptyx tener

The ultrastructure of the light organ Pteroptyx tener was examined using a Carl Zeiss Axioscope microscope and transmission electron microscope (TEM). The light organ of the male and female P. tener comprises of two layers namely the photogenic layer and the dorsal (reflector) layer. Photogenic layer consists of several elements, i.e. photocyte, differentiated zone, cylinder, trachea and trachea end cell. The photocyte is the main source of the emitted light. This layer is packed with photocyte granules except at a differentiated zone that have low granules but high number of mitochondria. The reflector layer comprised of trachea and the cytoplasm of the cells in this layer is densely packed with spherical uric acid granule. The finding of this study has shown that P. tener have similar general histology structure of light organ of fireflies species that produce sharp flashes. However, the cylinder and trachea end cell may have significant capacities in controlling the luminescent creation in the fireflies that need to be investigate further

Kepelbagaian dan taburan serangga ranting pada altitud berbeza di Gunung Jerai, Kedah, Malaysia

Phasmatodea merupakan kumpulan serangga yang sangat unik kerana mempunyai kebolehan penyamaran yang sempurna oleh morfologi luarannya yang mampu menyerupai ranting kayu, kulit kayu, kayu mati dan daun. Kajian ini dijalankan bagi mengenalpasti kepelbagaian dan taburan spesies serangga ranting pada altitud berbeza di Gunung Jerai, Kedah Malaysia. Pensampelan secara aktif dijalankan menggunakan lampu suluh LED berintensiti tinggi. Semua spesimen dikira dan direkodkan dan hanya spesies serangga ranting yang jarang dijumpai sahaja ditangkap dan dibawa pulang ke makmal bagi proses pengawetan dan disimpan sebagai rekod di Pusat Sistematik Serangga di Universiti Kebangsaan Malaysia. Secara keseluruhan, sejumlah 400 individu daripada 32 spesies, empat famili dan lima subfamili serangga ranting telah berjaya disampel. Famili Lonchodidae diwakili oleh 27 spesies dalam 15 genus, Phasmatidae dua spesies dalam dua genus, Heteropterygidae dua spesies dalam dua genus dan Aschiphasmatidae satu spesies dalam satu genus. Lopaphus iolas merupakan spesies serangga ranting paling kerap ditemui dalam kajian ini. Hasil dari kajian ini adalah rekod yang pertama mengenai fauna serangga ranting di Gunung Jerai, Kedah dan boleh dijadikan asas dan rujukan kepada penyelidik lain bagi menjalankan kajian lanjutan di kawasan ini

Distribution of serotonin (5-HT) and dopamine (DA) on digestive tract of red palm weevil larva, Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae)

The red palm weevil (RPW), Rhynchophorus ferrugineus (Coleoptera: Dryopthoridae) is a well-known deadly pest of palmae tree worldwide. The larvae of RPW is the most destructive stage of its life cycle and caused great economic lost to palm tree plantation for example the coconut tree plantations. In this study, we focused on detection of two important biogenic amines, serotonin (5-HT) and dopamine (DA) that play important roles in the regulation of the digestive tract of this insect. Immunohistochemistry analysis has been carried out on the cross-sectioned tissue of three different parts of the digestive tract; foregut, midgut and hindgut. 5-HT receptor for serotonin and D1 receptor for dopamine were chosen for chromogenic detection of the biogenic amine. The distribution of 5-HT can be detected at the plasma membrane, basement membrane and cytoplasm of the cell for the whole guts except at the midgut cell. While DA can only be detected at the basal membrane of the gut cell for the most part of the gut. Further study could be done to find a possible solution in controlling the survival of RPW by understanding the roles of the biogenic amine in controlling and modulating the mechanism of absorption and digestion of the digestive tract

The localization of luciferase in pteroptyx tener (coleoptera: lampyridae) light organ

Firefly is famously known for the light emission from its abdominal light organ. Light produce by firefly is known as bioluminescence. Luciferase is the enzyme that catalyze the light emitting reaction that produce bioluminescence. Haematoxylin and Eosin staining were used to describe the histological structure of the light organ. Localization of luciferase was discovered by immunohistochemical staining with polyclonal anti-luciferase and DAB chromogen as secondary antibody. Microphotography of light organ tissues was taken by Carl Zeiss Axio Scope A1 photomicroscope. This study revealed that the luciferase enzyme located at the photocyte cytoplasm of photogenic layer. This finding is an initial step to fully understand the regulation of synchronous light production in P. tener

Kepekatan kandungan enzim lusiferase dan morfometrik organ cahaya kelip-kelip, Pteroptyx tener (Coleptera: Lampyridae) spesies jantan dan betina

Kelip-kelip spesies Pteroptyx tener (Coleoptera: Lampyridae) menjadi daya tarikan utama dalam industri eko-pelancongan di Malaysia kerana hanya spesies kelip-kelip ini mampu menghasilkan kerlipan cahaya secara serentak dan berkumpulan. Kerlipan cahaya ini terhasil dari tindakan biokimia enzim lusiferase pada organ cahaya yang terletak di bahagian abdomen, di mana individu jantan menghasilkan cahaya lebih terang berbanding individu betina. Namun, kandungan enzim lusiferase yang terlibat dalam penghasilan cahaya ini tidak pernah dilaporkan ke atas spesies ini. Oleh itu, kajian ini bertujuan untuk menentukan kandungan enzim lusiferase pada organ cahaya kelip-kelip spesies jantan dan betina P. tener. Pengukuran morfometrik organ cahaya turut dilakukan untuk melihat perbezaan dan persamaan di antara morfologi organ cahaya jantan dan betina P. tener. Sebanyak 10 individu kelip-kelip P. tener jantan dan betina telah disampel dari Kampung Kuantan, Kuala Selangor, Malaysia. Hanya bahagian abdomen telah diambil bagi mengukur kuantiti enzim lusiferase yang ditentukan dengan melakukan ujian Asai Imunoerap Terangkai Enzim (ELISA). Kandungan kepekatan enzim lusiferase pada individu jantan didapati lebih tinggi dan menunjukkan perbezaan signifikan (P<0.05) iaitu 6.03±0.48 ng/mL (n=10) berbanding spesies betina iaitu sebanyak 2.94±0.27 ng/ml (n=10). Perbezaan perimeter organ cahaya spesies jantan lebih besar dan menunjukkan perbezaan signifikan (P<0.05) iaitu 5.85±0.44 mm (n=20) berbanding spesies betina iaitu 3.52±0.37 mm (n=20). Hasil kajian ini menunjukkan saiz organ yang lebih besar pada kelip-kelip jantan mengandungi kepekatan enzim lusiferase yang lebih tinggi berbanding kelip-kelip betina yang seterusnya menyumbang kepada perbezaan cahaya yang lebih terang pada individu jantan. Maklumat ini boleh digunakan bagi mempromosikan keunikan kumbang ini pada indusri ekopelancongan kelip-kelip

Effect of larval food amount on in vitro rearing of Indo-Malayan Stingless Bee Queen, Heterotrigona itama (Hymenoptera : Apidae; Meliponini)

The demand for stingless bee colonies in Malaysia has considerably increased due to the rapid advance of meliponiculture in using the stingless bees as agricultural pollinators, as well as the commercialization of stingless bee products (i.e. honey, bee bread and propolis). Thus, in vitro queen rearing for a large scale and rapid colony multiplication must be developed in order to fulfil the public requirements in a short period. Little is known about the in vitro rearing of native stingless bee queen, Heterotrigona itama. Therefore, in this study, we investigated the amount of larval food required by H. itama queen by comparing three different amounts of larval food, viz., 100 μL, 120 μL and 150 μL. All treatments were controlled under 100% relative humidity for the first 6 days, and 75% relative humidity for the rest of larval development until queen adult emergence, under 30 °C incubator temperature. The results showed that larvae of H. itama treated with the highest amount of larval food (150 μL) led to 78% of the queen’s emergence, whereas larvae treated with 120 μL and 100 μL of larval food resulted in 40% and 0% of queen emergence. The dynamic survival curve showed that most of the larvae died before the pupation phase and reached constant stability afterward. The queen’s body and abdominal length were significantly greater than wild workers. Microscopy analysis showed that in vitro queen had well-developed reproductive system with a huge ovary and spermatheca, whereas wild worker had much smaller ovary without spermatheca. Outcomes from this study could help increase the number of colonies on a large scale, allowing for their use both ecologically and economically, and contribute to conservation efforts in native species of stingless bees

Pengenalpastian Sensila pada alat mulut larva dan dewasa kumbang Palma merah, Rhynchophorus ferrugineus (COLEOPTERA: DRYOPTHORIDAE)

Sensila merupakan organ deria penting yang membolehkan serangga menghasilkan tindakbalas terhadap rangsangan sekitarannya. Serangga invasif seperti Kumbang Merah Palma, Rynchophorus ferrugineus atau lebih dikenali sebagai Red Palm Weevil (RPW), menggunakan organ derianya bagi mencari perumah yang spesifik dari Famili Palmaceae untuk kelangsungan populasinya. Kajian terhadap sensilla amat penting bagi kefahaman terhadap kelakuannya. Oleh itu, kajian ini menumpukan kepada pengenalpastian sensila pada alat mulut larva dan serangga dewasa RPW dengan menggunakan mikroskop elektron pengimbas (SEM). Hasil kajian mendapati bahawa pada alat mulut larva RPW terdapat lima jenis sensila yang terbahagi kepada 12 subjenis berbeza. Jenis sensila tersebut dibezakan berdasarkan struktur morfologi luaran iaitu sensila trikoid, sensila chaetica, sensila basiconica, sensila coeloconica dan organ digitiform. Sensila trikoid-larva merupakan sensila yang paling banyak ditemui pada alat mulut larva RPW. Bagi organ sensila pada alat mulut RPW dewasa pula, sebanyak enam jenis sensila dengan 15 subjenis telah dikenalpasti iaitu sensila trikoid, sensila chaetica, sensila basiconica, sensila coeloconica, sensila microtrichia, dan sensila kampaniform. Daripada kesemua jenis sensila tersebut, organ digitiform hanya ditemui pada alat mulut larva manakala sensilla mictorichia dan sensilla kampaniform hanya ditemui pada alat mulut RPW dewasa. Sensila reseptor mekanikal adalah yang paling banyak ditemui pada larva RPW manakala pada kumbang RPW dewasa pula sensila reseptor kimia adalah yang terbanyak. Jenis, jumlah dan taburan sensila yang berbeza pada RPW larva dan dewasa menunjukkan fungsi dan keperluan yang berbeza di antara peringkat hidup tersebut. Kajian ini menyediakan maklumat asas bagi pemahaman biologi dan kelakuan RPW yang boleh digunakan dalam merancang pengawalannya pada masa akan datang

Feeding and Amines Stimulate the Growth of the Salivary Gland following Short-Term Starvation in the Black Field Cricket, <i>Teleogryllus commodus</i>

The salivary gland of the black field cricket, Teleogryllus commodus Walker changed size between being starved and fed. Crickets without access to food for 72 h showed a reduction in both wet and dry mass of the glands compared with the glands from continuously fed animals at 72 h. Glands returned to size following ingestion within 10 min. Salivary glands of starved crickets (72 h) were incubated in saline containing either serotonin (5-HT) or dopamine (DA). Glands increased to pre-starvation size after 1 h incubation in situ with either 10−4 moles L−1 5-HT or 10−4 moles L−1 DA, although lower concentrations (10−5 moles L−1) did not affect gland size. From immunohistochemistry, amines appeared to shift from zymogen cells during starvation to parietal cells following feeding. High-performance liquid chromatography showed that serotonin concentration is higher than dopamine in the salivary gland removed from starved and fed crickets, but the quantity of these compounds was not dependent upon feeding state; the amine quantities increased as gland size increased. Further work is necessary to determine what might be the stimulus for gland growth and if dopamine and serotonin play a role in the stimulation of salivary gland growth after a period of starvation