White-spotted Longicorn Research Articles

Improving Contagion and Horizontal Transmission of Entomopathogenic Fungi by the White-Spotted Longicorn Beetle, Anoplophora malasiaca, with Help of Contact Sex Pheromone.

Simple SummaryThe white-spotted longicorn beetle, Anoplophora malasiaca, is one of the most destructive pests of many fruits and street trees. Effective controls are needed because the effect of marketed insecticides is limited. Entomopathogenic fungi offer a solution, combination with the beetles’ contact sex pheromone. The surface of the female body is covered with contact sex pheromone, which we extracted. Males held onto a glass model coated with female extract for 5 h, but males held onto one without extract for <0.3 h. Males that held onto coated model, attached to fabric impregnated with an entomopathogenic fungus, Beauveria brongniartii, picked up significant fungi. The fungi were then transferred to females during mating. Our results indicate that a combination of contact pheromone with a pathogen could improve entomopathogenic infection of both male and female beetles.The white-spotted longicorn beetle, Anoplophora malasiaca, is one of the most destructive pests of horticultural crops and street trees. Effective controls are needed because the effect of marketed insecticides is limited. Entomopathogenic fungi offer a solution, and improving the rate of infection would be a breakthrough in this beetle’s control. The combination of pathogenic fungi and the beetle’s contact sex pheromone was suggested. The surface of the female body is covered with contact sex pheromone, which elicit male mating behavior. To develop a method for the practical control of this beetle, we evaluated the arrestant activity of female extract containing contact pheromone coated on a black glass model. Males presented with a coated model held on for 5 h (mean) during an 8-h experiment. In contrast, males presented with a control model held on for <0.3 h. Males that held onto coated models attached to fabric impregnated with conidia of the fungus Beauveria brongniartii picked up much conidia, which they then passed on to females during mating.

Inspection of frass ejection could decrease the risk of white-spotted longicorn beetle Anoplophora malasiaca (Coleoptera: Cerambycidae) infestation of Japanese pine bonsais to negligible levels

To evaluate the infection risk of Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae) in two species of Japanese pine bonsais (Japanese black pine and Japanese white pine), feeding and oviposition preferences of female A. malasiaca to pine bonsai and mandarin orange were examined. A female was released into a net cage together with a pair of one pine bonsai and one mandarin orange. All mandarin oranges used in preference tests were damaged by feeding and deep biting scars from females, and larval frass ejection from the trunk was found in some mandarin oranges within 4 months of observation. However, these scars were found on only a few pine bonsais, and frass ejection was not found in any pine bonsais. No A. malasiaca larvae were detected in these pine bonsais. Therefore, frass ejection from trunks might be indicative of the presence of larvae. In field surveys at bonsai nurseries, no A. malasiaca adults were found on the pine bonsais and no pine bonsais exhibited frass ejection. Statistical analyses of these results suggested that the risk of A. malasiaca infestation in pine bonsais could be ruled out as a negligible level by confirming an absence from the trunk of frass ejection.

Pheromone synthesis. Part 264: Synthesis of the core 3-oxabicyclo[3.3.0]octane structures of gomadalactones A, B and C, the components of the contact sex pheromone of the white-spotted longicorn beetle, Anoplophora malasiaca

The core bicyclic cyclopentanelactone structures of gomadalactones A, B and C with α-hydroxyketone system were synthesized from (R)-pulegone, employing deconjugation of an α,β-unsaturated lactone as the key step. Comparison of the CD spectra of the synthetic compounds with those of the natural products confirmed the absolute configuration of the natural pheromone components as proposed in 2007. X-ray crystallographic analysis of the model compound of gomadalactone B core structure was carried out.

Host plant affects the sexual attractiveness of the female white-spotted longicorn beetle, Anoplophora malasiaca.

Anoplophora malasiaca (Coleoptera: Cerambycidae) is a serious pest that destroys various landscape and crop trees in Japan. We evaluated the precopulatory responses of three different A. malasiaca populations collected from mandarin orange, willow and blueberry trees. Most of the males accepted mates from within the same host plant population as well as females from the willow and blueberry populations. However, significant number of males from the blueberry and willow populations rejected females from the mandarin orange population immediately after touching them with their antennae. Because all three of the female populations produced contact sex pheromones on their elytra, the females of the mandarin orange population were predicted to possess extra chemicals that repelled the males of the other two populations. β-Elemene was identified as a key component that was only found in mandarin orange-fed females and induced a rejection response in willow-fed males. Our results represent the first example of a female-acquired repellent against conspecific males of different host plant populations, indicating that the host plant greatly affects the female’s sexual attractiveness.

Population differences in male responses to chemical mating cues in the white-spotted longicorn beetle, Anoplophora malasiaca

Adult Anoplophora malasiaca beetles were collected from field populations inhabiting three different host plants: Citrus, Salix and Vaccinium. Male orientation responses towards odours of wounded branches of each host plant were examined. Males of all three populations were attracted most frequently to odours of their original hosts, indicating that male orientation behaviour was induced by the odours of the plants from which they were originally collected. We also observed the mating responses of the males to elytra extracts from young and mature females of the three populations and chemically analysed those extracts. Citrus males were highly responsive to female extracts, regardless of origin. Salix males were less reactive than Citrus males, but responded moderately to female extracts of all populations. Vaccinium males were never attracted to Citrus female extracts and responded more to extracts from mature Vaccinium and Salix females, indicating that males might distinguish female origin and maturity. All eight hydrocarbons, four ketones, and three lactones that were previously identified as female contact sex pheromones were found in the extracts of three populations and both ages. Higher amounts of lactones on mature females likely caused greater male responses. These results suggested that males would be more likely to approach a female feeding on the same host plant and subsequently recognise her sexual maturity based on the profile of contact sex pheromones on her elytra.

The effects of foods consumed after adult eclosion on the mate-searching behavior and feeding preferences of the white-spotted longicorn beetle Anoplophora malasiaca (Coleoptera: Cerambycidae)

The effects of changes in host plants on the mate-searching behavior and feeding preferences of the white-spotted longicorn beetle Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae) were examined. All individuals were raised on the same artificial diet until they became pupae. Analysis of the mate-searching behavior of the males showed that many more newly emerged males were attracted to the odor of the artificial diet than to an unbaited control. We prepared three groups of beetles and fed each group on different host plants for one week. The host plants used included the following: an artificial diet (containing Morus alba Linne), Citrus unshiu Marc. branches, and Vaccinium spp. branches. The mate-searching behavior of the males changed in relation to the plant supplied for feeding. Simultaneously, the preference among the three host plants was tested. The newly emerged males preferred the artificial diet. After a week of feeding on one of the three plants, however, the adult males selected and consumed significantly more of the plant that they had just experienced than the other plants. These results suggest that the male mate-location cue can be acquired after adult eclosion. In addition, the male beetles are capable of changing their host-plant preference. If they do so, they use different odor cues for mate location. Newly emerged A. malasiaca females showed no preference for their first choice of food among the three host plants presented, whereas the consumption was significantly larger on C. unshiu branches. After one week of feeding on different host plants, females chose their host plant after the adult stage as well as C. unshiu, but consumed mostly C. unshiu. These results suggest that the food preferences of females are different from those of males. The behavior of females may not be affected by chemical signals from their original host-plant species (as pupae) or from the host-plant species acquired when they emerge as adults.

The white-spotted longicorn beetle, Anoplophora malasiaca (Coleoptera: Cerambycidae), with a blueberry as host plant, utilizes host chemicals for male orientation

Volatile chemicals from Citrus and Salix host plants evoke orientation behavior in males of the species Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae). These chemicals are emitted from wounded branches. We hypothesized that when released, these chemicals may indicate the presence of an individual to other conspecifics. Insects that originate from different host plants may use different plant chemicals from their own host to communicate with conspecifics. To further explore this theory, we investigated this communication system in a population of A. malasiaca from a third host plant, blueberry (Vaccinium spp.). Males from a blueberry host (Vaccinium population) were attracted to the odor of wounded Vaccinium branches when released near a female model in the laboratory, as has been observed in males found on Citrus and Salix host plants. The Vaccinium branch extract that was attractive to the males was separated into six fractions, of which two were active. Three active compounds were subsequently identified: β-caryophyllene and sulfur from the hexane fraction, and (E)-phytol in the weakly polar fraction. The latter two active compounds of Vaccinium branches were different from those found in Citrus and Salix.

Genetic variation of the white-spotted longicorn beetle Anoplophora spp. (Coleoptera: Cerambycidae) in Japan detected by mitochondrial DNA sequence

Genetic variation of the white-spotted longicorn beetle Anoplophora spp., distributed on the Japanese mainland and the Ryukyu Islands, was examined using nucleotide sequences of mitochondrial DNA. Two fragments, a 1.2-kb-long fragment containing portions of the cytochrome oxidase subunit I and II genes and a 1.4-kb-long fragment containing portions of 16S and 12S rDNAs, were sequenced. In phylogenetic analyses based on the sequences, 294 individuals collected at 75 localities were divided into two major groups (groups A and B) and then split into seven subgroups (A1–A4 and B1–B3). In group A, the closely related subgroups A1, A2, and A3 were mainly distributed on the Japanese mainland and were roughly separated among geographic areas, although the range of A3 spread significantly from Kyushu to the Central Ryukyu Islands. The sequence of A4, detected from one individual collected in eastern Honshu, was almost the same as that reported for A. chinensis (Forster) on the Chinese continent. In group B, subgroups B1 and B2 were restricted to the Central and Southern Ryukyu Islands, respectively, while B3 was distributed widely in both regions. Based on the results, we discuss the geographic origin of the haplotypes and movement of the insects between geographic areas.

Chemical communication in mate location and recognition in the white-spotted longicorn beetle, Anoplophora malasiaca (Coleoptera: Cerambycidae)

The mating sequence has been studied in the white-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae). Both females and males are attracted to wounded host plant Citrus unshiu, and adults of both sexes, and both female and male elytra contained the sesquiterpenes that were identical with those in C. unshiu. Moreover, at close range orientation by males, some visual cues derived from females acted synergistically with olfactory factors. And, female contact sex pheromone was isolated from female elytra and revealed to consist of eight hydrocarbons, four ketones, and three lactones. The mating sequence of A. malasiaca was roughly considered to occur as follows. Emerged adults from trunks of the host plants must search for their mates over large areas. Highly mobile males may be attracted from long distances by the signal of sesquiterpenes released from wounded host plants which indicate the presence of other individuals and serve for intraspecific communication in A. malasiaca. At close range orientation, the sesquiterpenes also act as attractant for both females and males, and then visual cue guided them to their mates or rivals. After a male orients to another individual, he identifies it as a mate or a rival. Once a male recognizes a female, mating occurs.

Sesquiterpene Hydrocarbons: Kairomones with a releaser effect in the sexual communication of the white-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae)

We conducted a series of experiments with the white-spotted longicorn beetle Anoplophora malasiaca (Thomson), and its host plant, Citrus unshiu, to examine the origin of the sesquiterpene hydrocarbons (SHCs; including β-elemene, β-caryophyllene, α-humulene, α-farnesene, and several unidentified compounds) that are contained in the elytra of the beetles and act as an attractant. In the laboratory, mechanically wounded citrus branches, as well as those fed upon by A. malasiaca, attracted males more frequently than intact branches. Solid phase microextraction (SPME) and subsequent analyses by gas chromatography (GC) analyses detected measurable SHCs from the air around both mechanically wounded and beetle-infested branches, as well as trace amounts from intact branches. The SHCs were also detected for a certain time from beetles that had fed on the citrus branches, but the amounts decreased rapidly after they were removed from the host. This decrease generally corresponded with a reduction of attractiveness of the beetles in a behavioural assay. Isolated females acquired the SHCs after exposure to, but not upon contact with, other females that had fed on C. unshiu branches. We hypothesize that the citrus SHCs are adsorbed in, retained on, and released from the wax layer of the beetle elytra. Since these compounds are released from branches when beetles feed, they may indirectly signal the presence of beetles to others in the field. The high response rate to SHCs by males is likely representing mate searching behavior. The SHCs act as kairomones with a releaser effect in the communication system of A. malasiaca.

Gomadalactones A, B, and C: novel 3-oxabicyclo[3.3.0]octane compounds in the contact sex pheromone of the white-spotted longicorn beetle, Anoplophora malasiaca

The ether extract of the females of white-spotted longicorn beetle Anoplophora malasiaca showed activity as contact sex pheromone to males. The extract was fractionated, and a pheromonal activity was revealed only when three fractions; n-hexane, n-hexane/EtOAc 9:1, and EtOAc were blended. The relative structures of gomadalactone A, B, and C, three active components isolated from the EtOAc fraction, were determined by spectroscopic studies to be (1 S ∗,4 R ∗,5 S ∗)-5-hydroxy-4-[( E)-7-hydroxy-4-methylhept-3-enyl]-4,8-dimethyl-3-oxabicyclo[3.3.0]octan-7-en-2,6-dione, (1 R ∗,4 R ∗,5 R ∗)-5-hydroxy-4-[( E)-7-hydroxy-4-methylhept-3-enyl]-4,8-dimethyl-3-oxabicyclo[3.3.0]octan-7-en-2,6-dione, and (1 S ∗,4 R ∗,5 S ∗,8 S ∗)-5-hydroxy-4-[( E)-7-hydroxy-4-methylhept-3-enyl]-4,8-dimethyl-3-oxabicyclo[3.3.0]octan-2,6-dione, respectively.

Host plant chemicals serve intraspecific communication in the white-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae)

Chemical components that attract males in the laboratory were extracted from the female elytra of the white-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae), and found to be comprised of several sesquiterpene hydrocarbons. Males located females that had fed on the bark of the host plant Citrus unshiu more frequently than those fed on an artificial diet in the laboratory. Male attraction was also confirmed in the corresponding sesquiterpene fractions of the host plant. The sesquiterpene fractions of female elytra and C. unshiu leaves showed quite similar GC profiles. In the field, the beetles were found on C. unshiu trees baited with intact females or males as frequently as those baited with the leaf extracts containing the sesquiterpenes at different purification levels. The beetles were found on those baited trees significantly more frequently than on unbaited control trees. Males, as well as females attracted both sexes, and the male elytra also contained the sesquiterpenes that were identical with those in female and C. unshiu. This indicated that active components in the elytra are acquired from C. unshiu by feeding, contact and/or adsorption. These sesquiterpenes may serve for intraspecific communication in A. malasiaca. The major sesquiterpenes from the C. unshiu leaves were isolated and elucidated by NMR analyses of four sesquiterpene hydrocarbons, β-elemene, β-caryophyllene, α-humulene, and α-farnesene.

Female orientation to the male in the white-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae) by visual and olfactory cues

White-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae), females were observed to use both olfactory and visual cues for orientation to males in the laboratory. When a freshly killed male was fixed at ca. 10 cm ahead and 5 cm to the right or left from a starting point on a 75° slope panel, 36% of the females oriented themselves toward the male before direct contact. Similar behavioral responses to a glass-rod model treated with male extract were observed. When a black or white glassrod treated with the extract was presented, the orientation toward the black rod was significantly greater than that to the white one. Few females oriented toward rods without extract. This indicates that the olfactory cue is essential for female orientation, and that a visual cue enhances the effect of the olfactory cue.

Effects of size and color of female models for male mate orientation in the white-spotted longicorn beetle Anoplophora malasiaca (Coleoptera: Cerambycidae)

We evaluated the effect of visual stimuli, mainly of size and color, on male mate orientation in Anoplophora malasiaca by experimenting with oval-shaped glass-rod models treated with female elytra extract. The number of males orientating to black glass-rod models corresponded to model size with larger model preferred. When same sizes of models of six different colors were compared, orientation frequencies significantly correlated to the lightness of the colors. Darker colors were preferred. This was also confirmed in male orientation to a series of gray-tone glass-rod models with different lightness. Thus, male orientation was influenced by both size and color of models that serve as visual stimuli.

Effects of male body size on mating behavior and female mate refusal in the white-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae)

In the white-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae), body size shows a large diversity both in males and females. We compared behavioral responses of different sizes of males to intact females and glass-rod models treated with female extract. Holding, mounting and abdominal bending responses to females were more frequently observed in small males than in large ones. Furthermore, small males showed these behaviors in response to lower doses of female extract than did large ones. However, females refused small males more frequently than large males, and approached the latter more frequently. This suggested that small males have high sensitivity to female sex pheromone that may offset the disadvantage of lower preference by females.

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉに及ぼす農薬の影響 第２報 圃場における数種殺菌剤の影響

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉに及ぼす農薬の影響 第２報 圃場における数種殺菌剤の影響

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉの培養担体の検討

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉの培養担体の検討

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉによるゴマダラカミキリの生物的防除に関する研究 第３報 菌の施用方法と殺虫効果

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉによるゴマダラカミキリの生物的防除に関する研究 第３報 菌の施用方法と殺虫効果

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉに及ぼす農薬の影響 第１報 数種殺菌剤の影響

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉに及ぼす農薬の影響 第１報 数種殺菌剤の影響

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉによるゴマダラカミキリの生物的防除に関する研究 第２報 ウレタンフォーム培養菌の樹幹バンド処理の効果

昆虫病原糸状菌Ｂｅａｕｖｅｒｉａ ｂｒｏｎｇｎｉａｒｔｉｉによるゴマダラカミキリの生物的防除に関する研究 第２報 ウレタンフォーム培養菌の樹幹バンド処理の効果