Coconut Hispine Beetle Research Articles

Laboratory evaluation of pathogenicity of Beauveria bassiana strains against Brontispa longissima Gestro (Coleoptera: Hispidae)

ABSTRACT The coconut hispine beetle, Brontispa longissima Gestro, is an invasive and economically important pest of palm trees in China. Beauveria bassiana has been used widely to control agriculture and forestry pests, for example, Dendrolimus punctatus Walker, Pantana phyllostachysae Chao, and Basilepta melanopus Lefevre. Until now, there is no published data on the use of B. bassiana against B. longissima. In this study, we identified highly pathogenic B. bassiana strains against different developmental stages of B. longissima under laboratory conditions. The BB-01 strain presented the highest virulence against B. longissima. After inoculating with the BB-01 strain at (1.0 ± 0.5) × 107 spores·mL−1for 10 d (28 ± 1°C with 95 ± 1% relative humidity), the corrected mortality of B. longissima adults reached 94.7% with a LT50 of 5.3 days. Mortality on other developmental stages was 84.4 ± 3.3% (LT50 = 5.8 d) for 1st-2nd instars, 76.1 ± 1.2% (LT50 = 6.71 d) for 3rd-4th instars, 73.7 ± 1.1% (LT50 = 6.98 d) for ≥5 instars, respectively. BB-01 median lethal concentrations (LC50) against 1st-2nd instar, 3rd-4th instar, ≥5 instar larvae and adults for 6 d were 9.0 × 106, 3.5 × 107, 4.8 × 107, 9.1 × 105 spores·mL−1, respectively. The BB-01 strain exhibited a lethal effect peak on B. longissima at 6–7 d after treatment. This study provides basic data about the pathogenicity of different B. bassiana strains on B. longissima.

Impacts of climate change and host plant availability on the global distribution of Brontispa longissima (Coleoptera: Chrysomelidae).

The coconut hispine beetle Brontispa longissima Gestro (Coleoptera: Chrysomelidae) is one of the most serious pests of the coconut palm, Cocos nucifera L. (Arecales: Arecaceae) and other palms. The invasion of B. longissima causes major economic and ecological losses worldwide. In this study, the impacts of climate change on the risk of spread were evaluated. CLIMEX was used to project its global potential distribution based on historical climate data (1987-2016) and simulated future climate data (2071-2100). The distribution of B. longissima included each continent under historical and future climate conditions. However, climate suitability was predicted to decrease in most tropical and subtropical regions under a climate change scenario. Temperature was a more important determinant of the climatic suitability of the pest than relative humidity or precipitation. The availability of host plants (Arecaceae) only had a slight impact on climate suitability in some regions. The projected potential distribution of B. longissima will help to determine the impacts of climate change and will provide supportive information for the development of management strategies to reduce future economic and ecological losses. © 2019 Society of Chemical Industry.

Genomic evaluations of Wolbachia and mtDNA in the population of coconut hispine beetle, Brontispa longissima (Coleoptera: Chrysomelidae)

Wolbachia pipientis is a diverse, ubiquitous and most prevalent intracellular bacterial group of alpha-Proteobacteria that is concerned with many biological processes in arthropods. The coconut hispine beetle (CHB), Brontispa longissima (Gestro) is an economically important pest of palm cultivation worldwide. In the present study, we comprehensively surveyed the Wolbachia-infection prevalence and mitochondrial DNA (mtDNA) polymorphism in CHB from five different geographical locations, including China’s Mainland and Taiwan, Vietnam, Thailand, Malaysia and Indonesia. A total of 540 sequences were screened in this study through three different genes, i.e., cytochrome oxidase subunit I (COI), Wolbachia outer surface protein (wsp) and multilocus sequencing type (MLST) genes. The COI genetic divergence ranges from 0.08% to 0.67%, and likewise, a significant genetic diversity (π = 0.00082; P = 0.049) was noted within and between all analyzed samples. In the meantime, ten different haplotypes (H) were characterized (haplotype diversity = 0.4379) from 21 different locations, and among them, H6 (46 individuals) have shown a maximum number of population clusters than others. Subsequently, Wolbachia-prevalence results indicated that all tested specimens of CHB were found positive (100%), which suggested that CHB was naturally infected with Wolbachia. Wolbachia sequence results (wsp gene) revealed a high level of nucleotide diversity (π = 0.00047) under Tajima’s D test (P = 0.049). Meanwhile, the same trend of nucleotide diversity (π = 0.00041) was observed in Wolbachia concatenated MLST locus. Furthermore, phylogenetic analysis (wsp and concatenated MLST genes) revealed that all collected samples of CHB attributed to same Wolbachia B-supergroup. Our results strongly suggest that Wolbachia bacteria and mtDNA were highly concordant with each other and Wolbachia can affect the genetic structure and diversity within the CHB populations.

Antennal and abdominal transcriptomes reveal chemosensory gene families in the coconut hispine beetle, Brontispa longissima

Antennal and abdominal transcriptomes of males and females of the coconut hispine beetle Brontispa longissima were sequenced to identify and compare the expression patterns of genes involved in odorant reception and detection. Representative proteins from the chemosensory gene families likely essential for insect olfaction were identified. These include 48 odorant receptors (ORs), 19 ionotropic receptors (IRs), 4 sensory neuron membrane proteins (SNMPs), 34 odorant binding proteins (OBPs) and 16 chemosensory proteins (CSPs). Phylogenetic analysis revealed the evolutionary relationship of these proteins with homologs from Coleopterans or other insects, and led to the identification of putative aggregation pheromone receptors in B. longissima. Comparative expression analysis performed by calculating FPKM values were also validated using quantitative real time-PCR (qPCR). The results revealed that all ORs and antennal IRs, two IR co-receptors (BlonIR8a and BlonIR25a) and one SNMP (BlonSNMP1a) were predominantly expressed in antennae when compared to abdomens, and approximately half of the OBPs (19) and CSPs (7) were enriched in antennae. These findings for the first time reveal the identification of key molecular components in B. longissima olfaction and provide a valuable resource for future functional analyses of olfaction, and identification of potential targets to control this quarantine pest.

Solar Energy-Based Insect Pest Trap

Agriculture is the main occupation of Thai people. Farmers encounter the problems of various types of insect pests that harm crops and result in loss of productivity each year. Therefore, it is necessary for farmers to use pesticides to prevent crop damage. However, when pesticides are used in large quantity, they cause adverse impacts on people, animals and the environment. Instead of using pesticides, the government has to support other ways to prevent insect pests, including the use of biological agents and some insects etc. A previous study has shown that the ultraviolet light of light emitting diode tube could be used to lure “Coconut Hispine Beetle”(Plesispa reichei Chapuis), a damaging pest of coconut and a range of palm species. This study aimed to develop Solar Energy-Based Insect Pests Trap by using ultraviolet light emitting diode tube to lure the insect pests and 12 volt battery as power supply to light emitting diode tube. The battery charging system derives electrical energy from 20 watts of solar cell for use at night. This proposed Solar Energy-Based Insect Pests Trap has an automatic control system to lure insect pests when there is no sunlight and the system will be stop when the sun shines. The results of the system installation test showed that this proposed Solar Energy-Based Insect Pests Trap could lure several types of insect pests in vegetable and coconut plantations including Brotispa, Elephus beetles, and Aphis, etc.

Integrated Pest Management of Important Insect Pests of Coconut1

IPM or Integrated pest management is a strategy that integrates various methods of cultural, physical, mechanical, biological control and selection of pesticides as the last option. IPM is not only cost effective but simultaneously prioritized human and environmental safety. IPM is based on farmer’s local knowledge, acceptance and education. Several insects were reported as coconut pests in Asia and Pacific region. Among these pests, rhinoceros beetle, red palm weevil, coconut hispine beetle, coconut black headed caterpillar and coconut scale currently causing severe damage to coconut palms in the region. Rhinoceros beetle, Oryctes rhinoceros Linnaeus (Coleoptera: Scarabaeidae) is native to South Asia and Southeast Asia. Management of this pest is a combination of sanitation in plantations and surrounding, biological control by using Metarhizium anisopliae, Oryctes virus and pheromone trapping. Red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) outbreaks usually occur after infestation of rhinoceros beetle. Keeping the rhinoceros under control results in keeping the red palm weevil under control too. Pheromone trapping is also developed for reduction of this pest. Coconut hispine beetle, Brontispa longissima (Gestro) (Coleoptera: Chrysomellidae), is an invasive pest occurs in Southeast Asia and Pacific region. Biological control of the pest is recommended by releasing two species of parasitoids, Asecodes hispinarus Boucek (Hymenoptera: Eulophidae) and Tetrastichus brontispae Ferriere (Hymenoptera: Eulophidae). Coconut black headed caterpillar, Opisina arenosella Walker (Lepidoptera: Oecophoridae) is one of the key pests of coconut in South Asia and invaded Thailand in 2008. Management of this pest in its native region consisted of: 1) removing and burning of the infested leaves; 2) biological control by releasing parasitoids such as Goniozus nephantidis (Muesebeck), Bracon brevicornis (Wesmael), Brachymeria nephantidis Gahan; and 3) chemical control by trunk injection and applying systemic insecticides in the holes. Bacillus thruringiensis has been recommended for biological control of the black headed caterpillar in Thailand. Coconut scale, Aspidiotus destructor Signoret (Hemiptera: Diaspididae) has been reported as a serious in Philippines. Predators are significant biological control agents in limiting A. destructor populations. The most common natural enemies associated with the coconut scales are the coccinellid beetles Chilocorus spp., Azya trinitatis, Cryptognatha nodiceps, Rhyzobius lophanthae and Pentilia castanea. Local parasitoids, Comperiella, Aphytis and Encarsia also play important roles in keeping the pest under control. Application of insecticides could inducee the infestation of the scale. Biological controls is recommended for suppression of other coconut pests, such as slug caterpillars (Lepidoptera: Limacodidae) such as Parasa lepida Cramer; coconut leaf moth, Artona catoxantha Hampton (Lepidoptera: Zygaenidae); and coconut leafminer, Promecotheca cumingii Baly (Coleoptera: Chrysomelidae).

Variability in the Last Abdominal Sternum of Brontispa longissima Populations Using Outline-Based Geometric Morphometric Analysis

Mindanao. Moreover, it is argued that a successful control of the pest is based on correct identification for the inability to recognize distinct populations can have severe and costly consequences for pest management (3). There is, therefore, a need to consider the coconut hispine beetle (CHB) in details to stop its infestation in the country especially that different levels of infestation have been observed among the invaded localities. Morphological variability is a good start to better understand why the CHB have differed in the level of infestation, for distinct populations of agronomic pest differ only on little phenotypic characters and sometimes these may represent stable characters with genetic bases which are good bases for the study (4). This study applied the advanced tools of geometric morphometrics (GM) to be able to describe morphological diversity of B. longissima from different locations. Geometric morphometrics (GM) have the advantage to provide a consistent set of shape variables for hypothesis testing (5) and deliver the sound graphic analyses that quantify and visualize morphometric variation within and between organisms (6). This study uses outline-based GM analysis that extract the margin around the specimen and this is conducted to gain information on intraspecific variation of both female and male B. longissima that might explain its fitness. Since the last abdominal sternum of beetles is assosiated with a chitinous apodeme of variable shapes, (7) this study is therefore conducted in this structure to determine patterns of variation among populations of the coconut hispine beetle, B. longissima.

Effect of temperatures and cold storage on performance of Tetrastichus brontispae (Hymenoptera: Eulophidae), a parasitoid of Brontispa longissima (Coleptera: Chrysomelidae).

Laboratory studies were conducted to determine the effect of temperature and cold storage on the performance of Tetrastichus brontispae (Ferriere) (Hymenoptera: Eulophidae), one of the major endoparasitoids against coconut hispine beetle, Brontispa longissima (Gestro) (Coleptera: Chrysomelidae). The results revealed that T. brontispae could successfully parasitize host pupae under all seven tested temperatures, but no adult emergence was observed at 32°C. It was also revealed that temperatures between 24 and 26°C appeared to be the optimum temperatures for parasitism, as these temperatures resulted in the most parasitized pupae and a significantly higher emergence rate and progeny production. These measurements significantly declined at 20, 30, and 32°C. This study confirmed developmental periods of parasitoid progeny decreased as the temperature increased, and sex ratio of this female-biased parasitoid was not affected by rearing temperatures. More importantly, this study indicated that cold storage of parasitized pupae could extend up to 30 d at 10°C, and a longer storage period had a significant adverse effect on mean adult emergence and parasitism performance. Ten days might be the optimum cold-storage period at 10°C, as parasitism performance, emergence rate, and progeny production at this storage period were similar to the control of 26°C. Furthermore, the developmental period, emergence rate, and sex ratio of progeny that emerged from cold-stored parasitized pupae were not influenced by storage periods, whereas parasitism performance of progeny decreased as storage period increased. This study suggests that about 24–26°C would be the optimal temperature for mass production and release of T. brontispae for biological control of B. longissima . These results also provide novel findings that a period of 10 d at 10°C may be more suitable and acceptable for ideal cold storage of parasitized pupae of T. brontispae .

Suitability of four palm species for the development of the invasive pest Brontispa longissima (Coleoptera: Chrysomelidae) in the field

AbstractThe coconut hispine beetle Brontispa longissima (Gestro) supposedly originated in Indonesia and Papua New Guinea. It is a serious invasive pest of the coconut palm Cocos nucifera L. in Southeast and East Asia. In Japan, it has established itself using Satakentia liukiuensis (Hatushima) H.E. Moore as a main host on Ishigaki and Iriomote Islands where C. nucifera is rare. To assess the probability of further establishment of B. longissima in novel habitats where C. nucifera and S. liukiuensis are not available, we examined the suitability of four common palm species in Japan for oviposition and immature development of B. longissima: Chrysalidocarpus lutescens (Bory) H. Wendl., Phoenix roebelenii O'Brien, S. liukiuensis and Washingtonia filifera (Linden ex André) H. Wendl. When seedlings of the four palm species were placed in pots in an experimental field on Ishigaki Island, all four species were inhabited and infested by wild B. longissima adults. Oviposition and immature development were observed on P. roebelenii and S. liukiuensis but not on C. lutescens and W. filifera. When field‐collected adults were released into mesh bags enclosing the potted seedlings, they oviposited on all four species. The eggs developed into adults on P. roebelenii, S. liukiuensis and W. filifera. On C. lutescens, however, hatched larvae died during the first or second instar.

Effects of constant and fluctuating temperatures on development of the coconut hispine beetle, Brontispa longissima (Coleoptera: Chrysomelidae) and two species of parasitoid

The larval parasitoid Asecodes hispinarum Bouček has been used to control the coconut hispine beetle, Brontispa longissima (Gestro) in Vietnam. Although A. hispinarum has succeeded in suppressing B. longissima in southern Vietnam, biocontrol has not succeeded in central Vietnam. One factor underlying this failure might be the high temperature during the hot season. In the present work, we examined whether A. hispinarum parasitises the beetles within the range of temperatures that occur during the hot season in central Vietnam and we evaluated the potential use of the pupal parasitoid Tetrastichus brontispae Ferrière. Development of the beetle and two parasitoids was investigated at two constant temperatures (28 and 30°C) and at fluctuating temperatures from 25 to 35°C (corresponding to temperatures during the hot season in central Vietnam). B. longissima reached adulthood in all the temperature treatments. More than 70% of A. hispinarum emerged from hosts at 28°C, but none emerged at 30°C or under fluctuating temperature conditions, indicating that A. hispinarum cannot be used as a biological control agent in central Vietnam. However, T. brontispae could reproduce the next generation at all temperatures. These results suggest that T. brontispae is a potential agent for continuous biological control of B. longissima in central Vietnam.

Parasitisation of Tetrastichus brontispae (Hymenoptera: Eulophidae), a biological control agent of the coconut hispine beetle Brontispa longissima (Coleoptera: Chrysomelidae)

The gregarious endoparasitoids Tetrastichus brontispae Ferrière is one of the important natural enemies of the coconut hispine beetle Brontispa longissima (Gestro), a serious invasive pest on coconut palm plants (Cocos nucifera L.) in Southeast Asia. Development at different temperatures, effect of host and female ages, effect of food and oviposition frequency and superparasitism were investigated in the laboratory. Females were allowed only one attack against one host in all experiments. The wasp developed in a host between 19 and 30°C, whilst no wasp completed its immature development at 16 and 31°C. Host and female ages affected parasitisation. Parasitoid emergence was high on day 0 and day 1 pupal hosts, and younger females produced more offspring than older females. The longevity of the female was affected not only by food supply, but also by oviposition frequency. The female survived longer when oviposition frequency was low. However, the total number of hosts parasitised by the female during her lifetime did not differ at different oviposition frequencies. In superparasitism, although the percentage of adult emergence and body size of offspring decreased with an increasing number of attacks per host, a host parasitised by up to four females could produce parasitoid offspring.

A Comparison of Artificial Diets for Mass Rearing <I>Brontispa longissima</I> (Coleoptera: Chrysomelidae) as Hosts for the Larval and the Pupal Parasitoids

The coconut hispine beetle, Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae) is a serious pest of coconut palm. In this study, we developed an artificial diet for B. longissima so that the beetle could be used as a host for rearing two of its parasitoids, Asecodes hispinarum Boucek (Hymenoptera: Eulophidae) and Tetrastichus brontispae Ferrière (Hymenoptera: Eulophidae). The new artificial diet represents an improvement of our previous diet, which we used as a control. When beetle larvae were reared on the new diet, which contains cysteine but not cellulose powder and has twice as much coconut leaf powder as in the control, the adult emergence was 71% (approximately 2 times that in the control). We also examined the suitability of beetles fed on the new diet as hosts for the larval parasitoid A. hispinarum and the pupal parasitoid T. brontispae. The percentage of wasps that emerged from hosts that were fed the new diet was higher than that from the control-fed hosts. The new diet allowed both A. hispinarum and T. brontispae to produce adult wasps of the next generation, whereas the control only allowed T. brontispae to produce the next generation. These results suggest that the new diet is suitable for B. longissima and will facilitate mass-rearing of A. hispinarum and T. brontispae.

Cold tolerance of the coconut hispine beetle, Brontispa longissima (Coleoptera: Chrysomelidae) in Japan

The coconut hispine beetle, Brontispa longissima (Gestro), supposedly originated from Papua New Guinea and Indonesia but has recently invaded Southeast and East Asian countries where it has been causing serious damage to Cocos nucifera L. This insect also occurs on the Southwest Islands off Kyushu Island in Japan. To evaluate the potential northward range expansion of this insect in Japan, we investigated its cold tolerance at 0, 5, and 10 °C (egg, larva, pupa, and adult), 13 °C (adult), and 15 °C (egg and hatched larva). At 15 °C, few eggs hatched, and the larvae that hatched died within a few days of hatching. At 13 °C, Ltime95 was estimated to be 23 days for adults, with the most cold-tolerant developmental stage at 10 °C. At all developmental stages, Ltime95 of B. longissima was estimated to be 19 days at 10 °C, 8 days at 5 °C, and 5 days at 0 °C, suggesting the cold tolerance of this beetle is very low. Considering average daily temperatures, it is unlikely that B. longissima can establish itself north of Amami-Oshima Island, located in the far south off the main island of Japan.

Life history traits and damage potential of an invasive pest Brontispa longissima (Coleoptera: Chrysomelidae) on Satakentia liukiuensis

AbstractThe coconut hispine beetle Brontispa longissima has been causing serious damage to the coconut palm Cocos nucifera in the Pacific, and Southeast and East Asia. This beetle also attacks Satakentia liukiuensis, an endemic palm on Ishigaki and Iriomote Islands, Japan. To assess the potential impact of B. longissima on S. liukiuensis, we examined the development period, survival rate, egg production and body size of B. longissima on S. liukiuensis at 22–31°C and consumption of S. liukiuensis leaf at 28°C. We also examined these life history traits on C. nucifera at 28°C to compare with those on S. liukiuensis. Brontispa longissima completed their development and reproduced on S. liukiuensis at 22–30°C. Linear regression analysis was used to estimate the effective cumulative temperature (k) as 891.2 degree‐days, and the lower developmental threshold as 13.3°C. On the basis of these values and monthly average temperatures on Ishigaki Island, it was estimated that B. longissima has four generations per year on the island. Satakentia liukiuensis was less suitable for B. longissima than C. nucifera in terms of immature survival, development time, resultant adult size and reproduction. The low quality of S. liukiuensis as a host‐plant may prevent the outbreak of B. longissima, which has not occurred yet on Ishigaki and Iriomote Islands.

Effect of Larval Density on Development of the Coconut Hispine Beetle,Brontispa longissima(Gestro) (Coleoptera: Chrysomelidae)

The coconut hispine beetle,Brontispa longissimashows, aggregation in the field. To elucidate the effect of aggregation on larval developmental aspects, we examined the effects of larval density on various aspects of larval development and on survival rates. Recently we found thatB. longissimawas divided into two monophyletic clades by genetic analysis. Therefore, we also compared the results between two populations, from Ishigaki, Japan (ISH) and Papua New Guinea (PNG), which were representative of the two monophyletic clades ofB. longissima. In both ISH and PNG, the larval developmental period was shorter and the survival rate higher with rearing under high-density conditions than under isolated conditions. Similarly, fewer instars were required before pupation under high-density conditions than under isolated conditions.Brontispa longissimatherefore developed better under high-density conditions, and the trends in the density effect were similar between two monophyletic clades.

Artificial diets for rearing the coconut hispine beetle, Brontispa longissima (Coleoptera: Chrysomelidae), and their suitability to two specialist parasitoids

The coconut hispine beetle, Brontispa longissima (Gestro), is a serious invasive pest that infests young unopened fronds of coconut palms (Cocos nucifera L.) in Southeast Asia. We previously developed the first artificial diet for rearing B. longissima larvae, which contained a leaf powder of young coconut fronds. Because the fronds are required for healthy growth of coconut palms, it is necessary to reduce their use for rearing the beetles. In this study, we tested two new artificial diets for the beetle larvae, which contained the leaf powders of mature coconut leaves or orchard grass (Dactylis glomerata L.). Brontispa longissima successfully developed from hatching to adulthood on both the mature coconut leaf diet and orchard grass diet. The beetles reared on the mature coconut leaf diet and orchard grass diet developed faster than those reared on the young coconut leaf diet. Fecundity and egg hatchability of beetles did not differ among the three diet treatments. We then examined the suitability of beetle larvae or pupae reared on each diet as hosts for two specialist endoparasitoids, Asecodes hispinarum Boucek and Tetrastichus brontispae Ferriere. The survival rate from oviposition to adult emergence for A. hispinarum was 43.8% in hosts reared on a young coconut leaf diet, 77.1% on a mature coconut leaf diet, and 85.7% on an orchard grass diet. For T. brontispae, the survival rate was 70.0% in hosts reared on the young coconut leaf diet, 38.1% on the mature coconut leaf diet, and 66.7% on the orchard grass diet. Our results indicate these artificial diets can be useful for rearing B. longissima and its two parasitoids, helping to reduce the costs of mass rearing these insects.

Induction of host-plant preference in Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae)

The coconut hispine beetle, Brontispa longissima, is a serious invasive pest of coconut palm (Cocos nucifera) in Southeast Asia and the Pacific region. Recently, however, it has been reported that on Ishigaki Island, Japan, where C. nucifera is rare, the endemic palm Satakentia liukiuensis serves as a regular host. To explore this phenomenon, we examined the preferences of the beetle for the two palm hosts by choice tests and measurements of feeding amount using four different groups: naïve adults obtained from a colony reared on C. nucifera (NC); naïve adults from a colony reared on S. liukiuensis (NS); wild adults collected on C. nucifera on Ishigaki Island (WC); and wild adults collected on S. liukiuensis on Ishigaki Island (WS). Both NC and NS consumed significantly more C. nucifera leaves than S. liukiuensis leaves and were observed more often on the leaves of C. nucifera. These results suggest that B. longissima has an innate preference for C. nucifera. In contrast, field-collected adults (WC, WS) initially showed preferences for the species on which they were collected, but after exposure to the other host plant for 2 weeks, their preferences for that host increased. These results suggest that the feeding experience of B. longissima adults affected their subsequent host preferences. This flexible host preference may have facilitated the beetle’s successful establishment in novel Japanese habitats where the original host plant was rare.

Suitability of Potential Host Plants in Japan for Immature Development of the Coconut Hispine Beetle, Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae)

The coconut hispine beetle, Brontispa longissima is a foliage feeder of the coconut palm, Cocos nuci- fera and other palm plants. Because B. longissima, supposedly native to Indonesia and Papua New Guinea, is now distributed in Ishigaki, Okinawa and Ogasawara, mainland Japan faces the potential risk of invasion by this pest. Suitability of palms other than C. nucifera for development and repro- duction of B. longissima has been neglected, and the possibility of the other palms as alternative food plants for mass-rearing of this insect has not been evaluated. To evaluate the potential risk to palms in Japan and the possibility of the palms as alternative food plants, we examined host plant suitability for immature development of B. longissima, using the following exotic and native plants in Japan, Chrysalidocarpus lutescens, Collinia elegans, Livistona chinensis, Phoenix canariensis, Rhapis excel- sa, Rhapis humilis, Washingtonia filifera, and Typha latifolia. When given each of those plant leaves, the percentage survival from first instar to adult emergence was 70% on C. lutescens, 55% on L. chin- ensis, 45% on P. canariensis, 80% on W. filifera, and 45% on T. latifolia. The adults given one of these suitable plants during larval and adult stages oviposited. Although larvae fed on C. elegans, R. excelsa or R. humilis, they never developed to pupae. When given a choice among the suitable plant species, B. longissima adults preferred W. filifera over the other plants. Considering suitability for immature development and reproduction of B. longissima, the ornamental palms such as C. lutescens, L. chinensis, P. canariensis, and W. filifera can be potential hosts in mainland Japan.

An invasive pest Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae) attacks an endemic palm in the Yaeyama Islands, Japan

The coconut hispine beetle Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae) is considered native to Indonesia and Papua New Guinea, and it has been established and causing serious leaf damages on Cocos nucifera (L.) in Asia, Australia and the Pacific Islands. Although this insect was found on only C. nucifera in the Yaeyama Islands, Japan in the 1980s, it was unknown whether it had established in the islands and whether it attacked the endemic palm Satakentia liukiuensis (Hatusima) H. E. Moore. We conducted field surveys in the Yaeyama Islands in 2007 to 2009 to determine whether B. longissima causes serious damages on S. liukiuensis in the islands. Although B. longissima infested leaves of the young trees in most nurseries or roadsides on Ishigaki, Iriomote and Kohama islands, no serious damage was observed on wild mature trees of the S. liukiuensis communities, which are protected as national natural monuments. All the developmental stages of B. longissima were found in November 2008 and May 2009. The present study first shows that B. longissima is common and attacks the endemic palm S. liukiuensis as a main host in the Yaeyama Islands where C. nucifera is very rare.

Artificial diets for rearing the coconut hispine beetle Brontispa longissima and its parasitoid Asecodes hispinarum

AbstractWe tested artificial diets for rearing the coconut hispine beetle, Brontispa longissima, a serious invasive pest of coconut (Cocos nucifera) in Southeast Asia. We examined three artificial diets that were identical except for their agar content. The survival rate from hatching to adult emergence was 26.0% when beetles were reared on a ‘soft diet’ (20 g/l agar), 16.0% on a ‘hard diet’ (40 g/l agar), and 41.0% on a ‘mixed diet’, in which the hard diet was used for the first instar and the soft diet for later instars. Females raised as larvae on the mixed diet and then as adults on the soft diet laid few eggs, which did not hatch. However, females reared on the mixed diet as larvae and then on fresh leaves as adults consistently laid eggs that hatched. We then examined the suitability of B. longissima larvae reared on the mixed diet as hosts for the larval parasitoid Asecodes hispinarum, a specialist parasitoid of this beetle. Of the oviposited hosts, 75.0% became mummified and 41.7% produced adult wasps. These results indicate that the mixed diet may be useful for rearing B. longissima larvae as hosts for the rearing of A. hispinarum.