Rhinoceros Beetle Research Articles

Global potential distribution of Oryctes rhinoceros, as predicted by Boosted Regression Tree model

Climate change is expected to have a significant influence on species range expansion, habitat shifts, and risk of biological invasion due to changes in survival rates, and rapid reproduction. This will tend to affect their geographical distribution and dispersal patterns, thereby threatening agriculture production and food security. Therefore, it is essential to understand the impact of climate change on the range shifts of an invasive species like the Asiatic rhinoceros beetle, Oryctes rhinoceros Linnaeus (Coleoptera: Dynastinae: Scarabaeidae), to inform policy formulation and preventive measures. To achieve this, we used environmental variables and occurrence records of O. rhinoceros to predict the current and future potential distribution of the pest under two representative concentration pathways (RCPs 4.5 and 8.5) for three time periods (2030, 2050, and 2080). We employed Boosted Regression Tree (BRT) and ArcGIS to create risk maps for the pest. The BRT model predicts an expansion of O. rhinoceros outside the current known distribution. The environmental variables which contributed the most to the geographical distribution of the pest were minimum temperature of coldest month (26.81 %), followed by precipitation of wettest month (20.61 %), temperature annual range (11.34 %), mean diurnal range (11.33 %), and elevation (4.49 %). Under the different climate change scenarios, O. rhinoceros will continue to threaten the economically important host plants until 2080. As a result, there will be a need for effective strategies to prevent its spread. Our predictions are reliable and have the potential to estimate the global distribution of the pest, as well as provide suggestions for prompt of O. rhinoceros prevention and management.

Trypoxylus dichotomus Gut Bacteria Provides an Effective System for Bamboo Lignocellulose Degradation.

ABSTRACTFast-growing bamboo may be a source of high-quality cellulose with the potential to contribute to energy sustainability, if an efficient and low-cost solution to bamboo cellulose decomposition can be developed. This study compared the gut microbiomes of rhinoceros beetle (Trypoxylus dichotomus) feeding on bamboo and wood fiber. The results revealed that diet has a distinctive effect on microbial composition in the midgut, including its most abundant microorganisms that in the fermentation and chemoheterotroph pathways. After identifying the 13 efficient bacterial isolates, we constructed a natural bacterial system based on the microbial relative abundance and an artificial bacterial system with equal proportions of each isolate to catabolize bamboo lignocellulose. The isolate Enterobacter sp. AZA_4_5 and the natural system showed higher degradation efficiency than other single strains or the artificial system. The results can thus serve as important reference for further research and development of a synthetic bacterial consortium to maximize lignocellulolytic ability.IMPORTANCE Bamboo produces a great yield of lignocellulosic biomass due to its high efficiency in carbon fixing. The gut microbiome of Trypoxylus dichotomus differed between bamboo and wood fiber diets. The lignocellulosic pathways were enriched in the gut bacteria of the bamboo diet. The highly efficient bacterial isolates were identified from midgut, whereas the natural bacterial system as well as one isolate showed the higher degradation efficiency of bamboo lignocellulose. The results indicate that the gut bacteria could provide an effective system to utilize the bamboo lignocellulosic biomass.

Biocontrol potential of native entomopathogenic nematodes against coconut rhinoceros beetle, Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae) under laboratory conditions

BackgroundIndia is the world's leading producer of coconuts. Many biotic and abiotic constrains limit global palm yield and among the biotic factors, the coconut rhinoceros beetle, Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae) is the major problem in India. The adult beetle attacks the unopened leaves and inflorescences, resulting in a yield loss of more than 10%. O. rhinoceros grubs and adults have different feeding habits as the adults feed on plant tissues, whereas the grubs primarily feed on rotting organic matter. Non-feeding stage, i.e. the larval stage, which is cryptic in nature and spends nearly 90–160 days in the breeding site, is amenable to any control measures so as to reduce the population of actual damaging adult stage. However, indiscriminate use of chemical insecticides has created a lot of environmental and regulatory issues, thus warranting an ecologically safe and environmental friendly alternative option. Hence, indigenous entomopathogenic nematode (EPN) strains, viz. Heterorhabditis indica (CPCRI-Hi1), Steinernema abbasi (CPCRI-Sa1), and S. carpocapsae (CPCRI-Sc1), virulence and reproductive capacity were evaluated against second instar larvae of O. rhinoceros.ResultsOryctes rhinoceros larval susceptibility to EPN significantly varied with the treatment dose and period of exposure. The highest larval mortality was observed with S. carpocapsae (100%), and S. abbasi (92%) at 10 days post treatment, whereas H. indica strain induced 72% mortality. At 72 h of incubation, the LC50 values of Sc1, Sa1 and Hi1 strains were 1078, 1663 and 9780 IJs larva−1, respectively. With different concentration of EPN tested, the production of infective juveniles (IJs) inside the cadavers for Sc1, Sa1 and Hi1 varied between 3223–10,365; 4722–96,572 and 3483–85,453 larvae−1, respectively.ConclusionBased on the virulence, reproductive capacity, searching ability and LC50 values, it is suggested that strain Sc1 have great potential as a biocontrol agent for the Oryctes management in coconut palms under humid tropical ecosystem. Present study found the effective native strain against O. rhinoceros, and its field efficacy should be tested further to include the EPNs in the integrated pest management program in coconut.

The Impact of Climate Change on Potential Invasion Risk of Oryctes monoceros Worldwide

As a significant threat to agriculture, pests have caused a great disservice to crop production and food security. Understanding the mechanisms of pests’ outbreaks and invasion is critical in giving sound suggestions on their control and prevention strategies. The African rhinoceros beetle, Oryctes monoceros (Olivier), as the most damaging pest of palms, banana, sugarcane, and pineapple, severely threatens their production due to its ability to kill both young and matured hosts. Analyzing the effect of climate change on major parameters of O. monoceros life history has been an important issue recently, given its sensitivity to thermal conditions. However, information on how climate change alters geographical distribution of O. monoceros is poorly understood. By combining environmental variables and occurrence records, we were able to assess environmental risk factors for O. monoceros and create risk maps for the pest using the Boosted Regression Tree model. Our results significance of environmental variables showed that the annual temperature variation (39.45%), seasonality of temperature (23.00%), the isothermality (18.76%), precipitation of the hottest quarter months (6.07%), average variation of day time temperature (3.27%), were relatively important environmental factors that affected the distribution O. monoceros. We also found that the projected potential distributions of the pest’s habitats in all future global warming scenarios exceeded its present known distribution. The model predicts that habitat suitability for O. monoceros is predominantly concentrated along Africa’s west and east coastlines, Asia’s south coasts, South America’s north and east coasts, and a few locations spread over North America’s southern coasts and coastal regions. These outputs provide a solid theoretical foundation for O. monoceros risk evaluations and control.

Efficacy of botanical formulations against coconut rhinoceros beetle oryctes rhinoceros

Field efficacy of botanical cakes and insecticides when evaluated in coconut against the rhinoceros beetle Oryctes rhiniceros L., revealed that leaf damage reduced to 9.5% with botanical cake and paste. Palms treated with chlorantraniliprole 0.4% GR (10.5%) and neem cake admixed with sand (11.5%) were also effective compared to control (40.0%) at 30 months after treatment (MAT). The leaf damage was significantly low (14.2%) in chlorantraniliprole 0.4%GR treated palms, and the next best was botanical cake and paste (15.2%). The palms treated with the botanical cake and paste revealed the least spear leaf damage of 15.0%, compared to that of chlorantraniliprole 0.4% GR (18.5%) and naphthalene balls (20.0%). The overall mean spear leaf damage was significantly lower in chlorantraniliprole 0.4% GR treated palms (40.4%) followed by palms treated with naphthalene balls (42.9%) and botanical cake and paste (44.4%) compared to control (78.9%).

A high-quality de novo genome assembly based on nanopore sequencing of a wild-caught coconut rhinoceros beetle (Oryctes rhinoceros)

BackgroundAn optimal starting point for relating genome function to organismal biology is a high-quality nuclear genome assembly, and long-read sequencing is revolutionizing the production of this genomic resource in insects. Despite this, nuclear genome assemblies have been under-represented for agricultural insect pests, particularly from the order Coleoptera. Here we present a de novo genome assembly and structural annotation for the coconut rhinoceros beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae), based on Oxford Nanopore Technologies (ONT) long-read data generated from a wild-caught female, as well as the assembly process that also led to the recovery of the complete circular genome assemblies of the beetle’s mitochondrial genome and that of the biocontrol agent, Oryctes rhinoceros nudivirus (OrNV). As an invasive pest of palm trees, O. rhinoceros is undergoing an expansion in its range across the Pacific Islands, requiring new approaches to management that may include strategies facilitated by genome assembly and annotation.ResultsHigh-quality DNA isolated from an adult female was used to create four ONT libraries that were sequenced using four MinION flow cells, producing a total of 27.2 Gb of high-quality long-read sequences. We employed an iterative assembly process and polishing with one lane of high-accuracy Illumina reads, obtaining a final size of the assembly of 377.36 Mb that had high contiguity (fragment N50 length = 12 Mb) and accuracy, as evidenced by the exceptionally high completeness of the benchmarked set of conserved single-copy orthologous genes (BUSCO completeness = 99.1%). These quality metrics place our assembly ahead of the published Coleopteran genomes, including that of an insect model, the red flour beetle (Tribolium castaneum). The structural annotation of the nuclear genome assembly contained a highly-accurate set of 16,371 protein-coding genes, with only 2.8% missing BUSCOs, and the expected number of non-coding RNAs. The number and structure of paralogous genes in a gene family like Sigma GST is lower than in another scarab beetle (Onthophagus taurus), but higher than in the red flour beetle (Tribolium castaneum), which suggests expansion of this GST class in Scarabaeidae. The quality of our gene models was also confirmed with the correct placement of O. rhinoceros among other members of the rhinoceros beetles (subfamily Dynastinae) in a phylogeny based on the sequences of 95 protein-coding genes in 373 beetle species from all major lineages of Coleoptera. Finally, we provide a list of 30 candidate dsRNA targets whose orthologs have been experimentally validated as highly effective targets for RNAi-based control of several beetles.ConclusionsThe genomic resources produced in this study form a foundation for further functional genetic research and management programs that may inform the control and surveillance of O. rhinoceros populations, and we demonstrate the efficacy of de novo genome assembly using long-read ONT data from a single field-caught insect.

Coconut Rhinoceros Beetle in Samoa: Review of a Century-Old Invasion and Prospects for Control in a Changing Future.

Simple SummaryCoconut rhinoceros beetle (CRB) is one of the major pests of coconut and oil palms in the Asia-Pacific region. Since its accidental introduction in Samoa in 1909, the invasive CRB has spread to several countries and territories within the Pacific and Indian Oceans, severely damaging coconut palms and affecting peoples’ livelihoods. In the 100 years since CRB established on Samoa, it remains the primary pest on the island with periods of heavy damage when integrated pest management (IPM) breaks down. The Samoan case is an excellent example of implementing biocontrol and IPM in a dynamic Pacific environment. As society and the economics of production in Samoa have changed, the level of control has varied, with recent concern about surges of the pest. The review synthesizes historical lessons and provide recommendations on how to protect coconut palms in the changing environment of Samoa which are also applicable for protection of palms in the wider Asia/Pacific region.It is now more than 100 years since the coconut rhinoceros beetle (CRB: Oryctes rhinoceros L.) was first detected in the Pacific Island state of Samoa. The exotic pest from Asia became the principal pest of coconut palms in Samoa and, from this first point of invasion, spread to several surrounding countries in the South-West Pacific Ocean. An intensive control operation was initiated, but the beetle could not be eliminated. Various pest management strategies were attempted but had limited success until the introduction of a biological control agent (BCA), Oryctes rhinoceros nudivirus (OrNV), during the late 1960s and early 1970s. The biocontrol release was very successful and became the prime example of “classical biological control” of an insect pest by a virus. Changing economic and social conditions in Samoa and other islands of the Pacific require a re-evaluation of the threat of CRB to coconut production to suggest how the IPM system may be modified to meet future needs. Therefore, it is timely to review the history of CRB in Samoa and summarize experiences in development of an integrated pest management (IPM) system limiting the impact of the pest. We also present results from a recent study conducted in 2020 on the island of Upolu to define the current status of the CRB population and its BCA, OrNV. The lessons from Samoa, with its long history of containment and management of CRB, are applicable to more recent invasion sites. Recommendations are provided to modify the IPM programme to enhance the sustainable control of CRB and support the ongoing coconut replantation program promoted by the Samoan government.

UJI PENINGKATAN KONSENTRASI Metarhizium anisopliae (Metsch.) PADA MEDIA KOMPOS DALAM MENGENDALIKAN LARVA Oryctes rhinoceros L.

The Rhinoceros beetle (Oryctes rhinoceros) is the main pest of palm oil (Elaeis guineensis Jacq.). Biological control using Metarhizium anisopliae fungus was effective in controlling O. rhinoceros. M. anisopliae fungus can be applied on palm oil empty bunches (POEB) which composted (Metankos). The research result in 2019 that a concentration of 50 g.l-1 M. anisopliae only kill 56% of O. rhinoceros larvae, so an increase in application concentration was tested. This research aimed to obtain the best concentration by increasing the concentration of M. anisopliae in POEB compost mixed with sawdust in controlling O. rhinoceros L. larvae. The research was conducted at The Plant Pest Laboratory Faculty of Agriculture University of Riau, to January until April 2021, using a completely randomized design (CRD), consist five treatment and four replications, concentration of M. anisopliae in compost was 55 g.l-1 water, 65 g.l-1 water, 75 g.l-1 water, 85 g.l-1 water, 95 g.l-1 water. The research showed that an increase in the concentration of M. anisopliae in compost of 75 g.l-1 water could be categorized as biopesticides because it caused an total mortality is 72,50 ± 5,00. The lethal concentrations 50% and 95% of M. ansiopliae in compost is 48 g.l-1 water approach to concentration 55 g.l-1 water and 140 g.l-1 water approach to concentration 95 g.l-1 water.

Bimodal frequency distribution as a criterion for dimorphism in male rhinoceros beetles (Coleoptera: Scarabaeidae: Dynastinae)

AbstractBateson & Brindley (1892) reported that males of the rhinoceros beetle Xylotrupes gideon are dimorphic (i.e. occurring in two distinct forms) with respect to size of the prominent cephalic horn. This claim was based on a comparison of frequency distributions for size of the horn (bimodal) and size of the body (unimodal). Bateson and Brindley did not realize, however, that a bivariate plot of horn length against body size follows a steep, S-shaped trajectory, or that steepness of such a curve—and not dimorphism—underlies the bimodal frequency distribution for size of the horn. The bivariate distribution for horn size vs. body size is continuous and without breaks or interruptions, so the beetles merely exhibit a pattern of allometric variation that went unrecognized at the time. Other species of dynastine beetle also display patterns of sigmoid allometry, but only those with the steepest slopes for the allometric curve also have bimodal frequency distributions for size of the horn. The concept of male dimorphism in X. gideon and other dynastine beetles needs to be reconsidered in the light of findings reported here and elsewhere.

Sex determination of Japanese rhinoceros beetles, Trypoxylus dichotomus (Coleoptera: Scarabaeidae), based on their dropping shape

The Mahalanobis-Taguchi system (MTS) is one of the multi-variate analyses which can classify by correlations among multi-variables. It has a significant advantage of applying a cause analysis which provides effective variable combinations to upgrade the accuracy of the classification. In this study, droppings, which were extruded from Japanese rhinoceros beetle larva (called Kabutomushi in Japanese) were classified into male/female based on their shape-related features using the MTS. Their droppings have a spheroid shape of approximately 10 mm in their long axis. Seven features (i.e., variables) were obtained from digital micrographic images using image analysis software, such as height/width (H/M), major/minor (Ma/Mi), perimeter/Feret diameter (P/F), projected area/Feret diameter (A/F), roundness, circularity, and solidity. Although an abnormality rate, which shows how the correlation pattern of one larval dropping is far from any standard ones, has a boundary in order to classify into male/female from 18 larval droppings, 3 larva were judged as the opposite sex. Based on the cause analysis, the A/F and solidity were the best variable combination which all the larval droppings were completely classified into male/female. Why these variables were affected by the sex most seemed to be caused by the gut components, as determined by time-domain nuclear magnetic resonance (TD-NMR). MTS has the great ability to classify from the powders’ minor difference and will be an effective tool for particle design in the near future.

Non-linear latitudinal cline of egg size and its consequence for larval survival in the rhinoceros beetle

Abstract The egg size of insects often exhibits latitudinal trends, which are attributed to local adaptations to temperature or temperature-related ecological factors. Although increased egg size improves offspring fitness, the relationship between size and fitness is influenced largely by environmental variables. Additionally, there is a trade-off between the size and number of eggs if the quantity of reproductive resources is constant. Despite the key associations among offspring size, number and performance, relatively few studies have jointly considered these traits when studying the genetic differentiation of egg size. Here, we examined the effects of latitude on egg size using 14 populations of the univoltine rhinoceros beetle Trypoxylus dichotomus (Coleoptera, Scarabaeidae, Dynastinae) along a 1200-km latitudinal gradient under common garden laboratory conditions. We found that egg size decreased with increasing latitude in a non-linear manner. Geographical variation in egg size was independent of maternal body size, and there was no difference in female lifetime fecundity between the low-latitude (large eggs) and high-latitude (small eggs) populations. Therefore, low-latitude females invest more resources in reproduction compared with high-latitude females. We further found that the larvae of the high-latitude population showed higher mortality than those of the low-latitude population under both nutrient-poor and nutrient-rich conditions. Although the ecological factors that shape the non-linear cline of egg size were not identified in our study, geographical variation in local environments or in female reproductive strategies could have caused the latitudinal trend.

POPULASI DAN TINGKAT SERANGAN KUMBANG TANDUK (Oryctes rhinoceros L.) PADA PERTANAMAN KELAPA SAWIT DI PT. CAKRA ALAM SEJATI, PROVINSI RIAU

The increasing area of oil palm plantations (Elaeis guineensis Jacquin) in Indonesia every year creates opportunities for pest that can harm oil palm plantations to develop, one of which is the coconut palm rhinoceros beetle (Oryctes rhinocheros Linnaeus). This research aims to determine the coconut palm rhinoceros beetle population, the percentage of plants attacked, and the intensity of the attack on the planting area Kebun-24 palm plantations of PT. CAS (Cakra Alam Sejati). In this research used a survey method on oil palm plantations Kebun-24. Determination of sample blocks was carried out by purposive sampling and plant samples were selected randomly. The location of the research was carried out in Pelalawan Regency, namely in the Kebun-24 plantation of PT. CAS, Riau Province. The results of the research, the highest population was TBM block with an average of 11.27 coconut palm rhinoceros beetle individuals. The highest coconut palm rhinoceros beetle population was in block 4c (1 year) with 86 imago individuals and 126 larvae individuals, while the lowest population was in block 11a (8 years) with 14 imago individuals and 68 larvae individuals. The highest percentage of affected plants was TM block with an average of 98.67%. The highest attack intensity of coconut palm rhinoceros beetle was TM block with an average of 37.07%. The percentage of affected plants and the highest attack intensity were in block 7b (6 years) with 100% percentage of affected plants and 37.60% attack intensity, while the lowest was block 14b (2 years) with 72.00% percentage of affected plants and 32, 00% attack intensity

Nylon nets: a simple pest exclusion barrier technique to manage rhinoceros beetle menace in coconut plantations

Oryctes rhinoceros (L.) is a major pest of palms worldwide. Seedlings and juvenile palms are more vulnerable to beetle damage and in severe cases, inflicting palm death. The present study was to develop a physical pest control technique for juvenile palms using nylon nets as a pest exclusion barrier. The unopened spear leaf with –two to four adjacent leaf bases were loosely wrapped with the nylon nets of different mesh size during June - December 2017 (N = 40). Results revealed that the damaged leaves were reduced from 61.02 to 7.53% (t = 17.23; p < 0.001). Further experiment was up scaled in 120 palms during June – December 2018 and the beetles trapped in nylon nets were recorded at weekly intervals. Nylon nets entrapped 618 adult beetles that comprised 61.80% females and 38.18% males with corresponding sex ratio of 1.61: 1. Thus, use of nylon nets as a pest exclusion barrier guarded the young palms from beetle attack and additionally acted as passive trap by entrapping 20.6 beetles/week/120 palms without any insecticidal intervention.

Development of IPM module for rhinoceros beetle (Oryctes rhinoceros L.) in juvenile coconut garden

Coconut (Cocos nucifera) is an important crucial plantation crop and prone to many pests and diseases. Rhinoceros beetle (Oryctes rhinoceros L.) is an important pest that causes damage and reduce the yield. During 2018, Gaja cyclone affected the coconut plantations in delta regions of Thanjavur, Thiruvarur and Nagapattinm Districts. Rhinoceros beetle was found to inflict severe damage in replanted young coconut seedlings. The present study was carried out to mitigate the damage due to rhinoceros beetle in coconut gardens. Shoot damage of 14.07, 11.36, and 18.17 per cent was recorded in Module - I recommended practice, Module - II IPM and module - III farmers’ practice respectively. The maximum shoot damage reduction of 37.48 per cent was observed over farmers’ practice recorded in Module - II IPM followed by recommended practice (22.56%). Module - II IPM was found to be effective against rhinoceros beetles than recommended practice and farmers’ practice.

RNA Interference Method for Gene Function Analysis in the Japanese Rhinoceros Beetle Trypoxylus dichotomus.

In the Japanese rhinoceros beetle Trypoxylus dichotomus, various candidate genes required for a specific phenotype of interest are listed by next-generation sequencing analysis. Their functions were investigated using RNA interference (RNAi) method, the only gene function analysis tool for T. dichotomusdeveloped so far. The summarized procedure for the RNAi method used for T. dichotomusis to synthesize double-stranded RNA (dsRNA), and inject it in larvae or pupae of T. dichotomus. Although some dedicated materials or equipment are generally required to inject dsRNA in insects, the advantage of the protocol described here is that it is possible to inject dsRNA in T. dichotomuswith one syringe.

Unveiling characteristic proteins for the structural development of beetle elytra

Beetles possess a set of highly modified and tanned forewings, elytra, which are lightweight yet rigid and tough. Immediately after eclosion, the elytra are initially thin, pale and soft. However, they rapidly expand and subsequently become hardened and often dark, resulting from both pigmentation and sclerotization. Here, we identified changes in protein composition during the developmental processes of the elytra in the Japanese rhinoceros beetle, Trypoxylus dichotomus. Using mass spectrometry, a total of 414 proteins were identified from both untanned and tanned elytra, including 31 cuticular proteins (CPs), which constitute one of the major components of insect cuticles. Moreover, CPs containing Rebers and Riddiford motifs (CPR), the most abundant CP family, were separated into two groups based on their expression and amino acid sequences, such as a Gly-rich sequence region and Ala-Ala-Pro repeats. These protein groups may play crucial roles in elytra formation at different time points, likely including self-assembly of chitin nanofibers that control elytral macro and microstructures and dictate changes in other properties (i.e., mechanical property). Clarification of the protein functions will enhance the understanding of elytra formation and potentially benefit the development of lightweight materials for industrial and biomedical applications. Statement of significanceThe beetle elytron is a light-weight natural bio-composite which displays high stiffness and toughness. This structure is composed of chitin fibrils and proteins, some of which are responsible for architectural development and hardening. This work, which involves insights from molecular biology and materials science, investigated changes in proteomic, architectural, and localized mechanical characteristics of elytra from the Japanese rhinoceros beetle to understand molecular mechanisms driving elytra development. In the present study, we identified a set of new protein groups which are likely related to the structural development of elytra and has potential for new pathways for processing green materials.

Justification of the rotary working bodies of the cultivator for processing between the rows of plantations of lavender oilseed on the basis of agricultural biomechanics

The article presents the methods and results of modeling in agricultural biomechanics, which made it possible to substantiate models of cultivator working bodies adapted to the soil environment based on rotary discs with teeth. The biological prototype of this design is the burrowing limb of a rhinoceros beetle. It is proposed to solve the problems of improving the shape of rotary discs with teeth on the basis of the use of a mechanical-bionic approach, which allows to analytically describe the dependencies for determining the minimum number of steps of cutting notches between the teeth and the number of teeth on the disc, as well as the rational value of their length. The use of a new type of working bodies - a toothed flat disc, designed in a bionic manner, will increase the efficiency of weed control during inter-row tillage, and also reduce traction resistance.

The contents availability of N, P, K, and Mg in empty fruit composting of oil palms with symbiont bacteria from rhinoceros beetle larvae (Oryctes rhinoceros) (Coleoptera: Scarabidae)

The using of palm oil waste had not been optimal lately. It could be seen in oil empty fruit bunches (EFB). It was placed along the oil palm plantations. The condition was not only the trigger of air pollution but also could invite rhinoceros beetle pests (Oryctes rhinoceros) to lay their eggs and carry out reproductive activities due to availability organic matter of the trees. Oil palm plants required large amounts of macro nutrients, especially potassium. However, the potassium nutrient was found in EFB was too slow available because of its relatively long breakdown. That was the reason why it was needed a method of using EFB waste into a capable of high use value product, environmentally friendly, and could give a lot of benefits to oil palm farmers. The purpose of this study was to determine the availability of nutrient content in EFB composting by the using of symbiont bacteria from larvae O. rhinoceros. The research was experimentally conducted a factorial randomized block design (RBD) with 2 factors, namely the type of bacteria and the time of decomposition. The composting stage was carried out by coarsely chopping the EFB then 75 ml of bacterial culture was applied to 1 kg of EFB. Analysis, results indicated C/N ratio (35.56% and 36.97%) and high K content (1.64% and 1.48%). The EFB composting method is achievable in 6 weeks with activators of Bacillus stratosphericus and Bacillus siamensis.

Incidence of Rhinoceros Beetle (Oryctes rhinoceros) and Eriophyid Mite (Aceria guerreronis) on a Coconut Plantation In Pollachi Area

A survey was carried out to identify the major insect pests in the coconut farm of the Pollachi area. There were two major pests viz., rhinoceros beetle, Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae), eriophyid mite, Aceria guerreronis Keifer (Acari: Eriophyidae) were predominant during the period of observation. Natural enemies viz., Chelisochus mori, and Campsomeriella collaris were identified, and the level of population was meagre. The incidence of rhinoceros beetle ranged from 36.26 to 41.97 % of which the highest incidence was recorded in B and E block, respectively. The incidence of eriophyid mite ranged from 4.52 to 16.45 %, against a minimum of 4.52 % noticed in D block. The incidence of rhinoceros beetle was maximum (43.50%) during April, followed by March month as compared to the lowest in January (34.7%). Similarly, the incidence of eriophyid mite was maximum (12.92%) during April followed by March (9.78%) as against the lowest incidence during January (7.40%). The peak occurrence of eriophyid mite was recorded during March and April might be due to the influence of either temperature or relative humidity.

Identification of Components of the Aggregation Pheromone of the Guam Strain of Coconut Rhinoceros Beetle, Oryctes rhinoceros, and Determination of Stereochemistry

The coconut rhinoceros beetle, Oryctes rhinoceros (Linnaeus 1758) (Coleoptera: Scarabaeidae: Dynastinae) (CRB), is endemic to tropical Asia where it damages both coconut and oil palm. A new invasion by CRB occurred on Guam in 2007 and eradication attempts failed using commonly applied Oryctes rhinoceros nudivirus (OrNV) isolates. This and subsequent invasive outbreaks were found to have been caused by a previously unrecognized haplotype, CRB-G, which appeared to be tolerant to OrNV. The male-produced aggregation pheromone of the endemic, susceptible strain of O. rhinoceros (CRB-S) was previously identified as ethyl 4-methyloctanoate. Following reports from growers that commercial lures containing this compound were not attractive to CRB-G, the aim of this work was to identify the pheromone of CRB-G. Initial collections of volatiles from virgin male and female CRB-G adults from the Solomon Islands failed to show any male- or female-specific compounds as candidate pheromone components. Only after five months were significant quantities of ethyl 4-methyloctanoate and 4-methyloctanoic acid produced by males but not by females. No other male-specific compounds could be detected, in particular methyl 4-methyloctanoate, 4-methyl-1-octanol, or 4-methyl-1-octyl acetate, compounds identified in volatiles from some other species of Oryctes. Ethyl 4-methyloctanoate elicited a strong electroantennogram response from both male and female CRB-G, but these other compounds, including 4-methyloctanoic acid, did not. The enantiomers of ethyl 4-methyloctanoate and 4-methyloctanoic acid were conveniently prepared by enzymatic resolution of the commercially-available acid, and the enantiomers of the acid, but not the ester, could be separated by gas chromatography on an enantioselective cyclodextrin phase. Using this approach, both ethyl 4-methyloctanoate and 4-methyloctanoic acid produced by male CRB-G were shown to be exclusively the (R)-enantiomers whereas previous reports had suggested male O. rhinoceros produced the (S)-enantiomers. However, re-examination of the ester and acid produced by male CRB-S from Papua New Guinea showed that these were also the (R)-enantiomers. In field trapping experiments carried out in the Solomon Islands, both racemic and ethyl (R)-4-methyloctanoate were highly attractive to both male and female CRB-G beetles. The (S)-enantiomer and the corresponding acids were only weakly attractive. The addition of racemic 4-methyloctanoic acid to ethyl 4-methyloctanoate did significantly increase attractiveness, but the addition of (R)- or (S)-4-methyloctanoic acid to the corresponding ethyl esters did not. Possible reasons for the difference in assignment of configuration of the components of the CRB pheromone are discussed along with the practical implications of these results.