Applied Entomology and Zoology
Online ISSN : 1347-605X
Print ISSN : 0003-6862
ISSN-L : 0003-6862
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Volume 44, Issue 3
Displaying 1-22 of 22 articles from this issue
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Regular Papers
  • Conservation ecological study of invasion of Bombus terrestris (Hymenoptera: Apidae) into a preserved area of the Notsuke Peninsula of eastern Hokkaido, Japan
    Maki N. Inoue, Satoe Ishikawa, Takeaki Inoue, Izumi Washitani
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 337-342
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.337
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    Recently Bombus terrestris has invaded into the peninsulas of eastern Hokkaido, northern Japan, where the restricted distribution range of the rare native species B. florilegus is located. To demonstrate the establishment status and flower use of B. terrestris, we investigated flower visits by bumblebees in 2007 in the Notsuke Peninsula. A total of 554 introduced and native bumblebees foraging mainly on native plants were recorded and B. terrestris foraged more frequently native plants than non-native plants. This species however was much less abundant, comprising only 2.5% of all observations. At the time of excavation, a feral B. terrestris nest found during the survey yielded 362 worker cocoons but no sexuals. Because the foundress was still alive and much food was stored in the nest, this colony likely would have been able to reproduce successfully if not excavated. Our results indicate successful naturalization of B. terrestris in the native grassland vegetation and the species has potential to negatively affect native bumblebee species.
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  • Molecular phylogeny of Stigmaeopsis spider mites (Acari: Tetranychidae) based on the Cytochrome Oxidase subunit I (COI) region of mitochondrial DNA
    Katsura Ito, Tatsuya Fukuda
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 343-355
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.343
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    The phylogenetic relationships of Stigmaeopsis spider mites (Acari: Tetranychidae) in Japan were investigated using the Cytochrome Oxidase subunit I (COI) region of mitochondrial DNA. The authors sequenced the samples from 81 individuals representing S. longus, S. celarius, S. takahashii, and S. saharai, which inhabit bamboo species of the genera Sasa and Phyllostachys (Poaceae; Bambusoideae), and two forms of S. miscanthi (HG and LW) living on Miscanthus sinensis (Poaceae; Panicoideae). Both the neighbour-joining and maximum-likelihood methods revealed that Stigmaeopsis consists of at least seven monophyletic groups, in which two forms of S. miscanthi form two distinct monophyletic groups, whereas each of bamboo-inhabiting species, S. celarius, S. takahashii, and S. saharai, was not monophyletic. The haplotypes of S. longus appeared in only a single clade, but coexisted with one of S. celarius. These results imply a mismatch between diagnostic morphological characters (i.e., the length of dorsal setae) and the phylogenetic lineages of bamboo-inhabiting species, requiring re-evaluation of the use of these characters. In addition, the results indicate that plural lineages coexist in a single habitat in various areas, suggesting that differentiated lineages have secondary encounters through the dispersal-and-colonization process.
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  • Northerly shift in voltinism watershed in Hyphantria cunea (Drury) (Lepidoptera: Arctiidae) along the Japan Sea coast: Evidence of global warming?
    Tadashi Gomi, Kumiko Adachi, Ai Shimizu, Katsuya Tanimoto, Eriko Kawab ...
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 357-362
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.357
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    The effects of climate change on the northern limit of the trivoltine area were clarified in the fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae). The Takaoka and Kanazawa populations used in the present study occur in locations to the north of Fukui (36.07°N), where H. cunea has recently shifted from a bivoltine to a predominantly trivoltine life cycle. The life-history traits of these populations were investigated and compared to those in the Fukui population. The lower threshold temperature for development and the thermal constant for one generation were 11.3°C and 674.5°d in the Takaoka population, and 11.2°C and 680.7°d in the Kanazawa population. The critical photoperiod for diapause induction at 25°C was 14 h 34 min in the Takaoka population and 14 h 28 min in the Kanazawa population. These critical photoperiods at 25°C were longer by 24 min and 18 min than the Fukui population, respectively. These results, together with climate data, suggest that the Takaoka population maintains a bivoltine life cycle, and a small part of the Kanazawa population has three generations per year, a predominantly bivoltine life cycle. Thus, the present northern limit of the trivoltine area lies around Fukui in districts along the Japan Sea.
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  • Effects of ingredients and structure of semi-artificial diet on the reproduction of an ambrosia beetle, Xyleborus pfeili (Ratzeburg) (Coleoptera: Curculionidae: Scolytinae)
    Takahiko Mizuno, Hisashi Kajimura
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 363-370
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.363
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    To develop a better system for rearing ambrosia beetles, we tested semi-artificial diets with different ingredients and structures. For the rearing of Xyleborus pfeili (Ratzeburg), we prepared diets composed of Douglas-fir sawdust, potato starch, dried yeast, sugar, and distilled water. The addition of antibiotics (streptomycin and penicillin) to a diet with a single-layer structure did not inhibit fungal contamination, and resulted in fewer X. pfeili offspring. Diets containing neither the starch nor the yeast effectively prevented fungal contamination, but did not produce offspring. A diet with a two-layer structure, in which different diets were placed in the lower layer (all ingredients) and the upper layer (sawdust, sugar, and water) in a glass tube, greatly increased the reproductive success of X. pfeili. The length of the gallery system, the number of offspring, their sex ratio, and the timing of gallery boring and oviposition by mother beetles on the two-layer structure were not significantly different from those on a three-layer structure used in previous research that also contained a thin layer of Douglas-fir resin. Thus, the diet with a two-layer structure appears to be a useful and simpler method for rearing ambrosia beetles.
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  • Duration and location of attraction to herbivore-damaged plants in the tachinid parasitoid Exorista japonica
    Kazushi Hanyu, Ryoko T. Ichiki, Satoshi Nakamura, Yooichi Kainoh
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 371-378
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.371
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    Odors from corn plants infested with the larvae of the noctuid herbivore Mythimna separata attract tachinid fly, Exorista japonica, females. We investigated the effects of elapsed time on the attraction of E. japonica to plants after host larvae were removed. The behavior of the flies within 5 min from introduction was observed in a wind tunnel. The percentage of flies attracted to the plants remained high (70%) for 5 h and decreased gradually after 24 h. The percentage of flies attracted to continuously damaged plants remained high for 5 days. In contrast, the percentage of flies reaching artificially damaged corn plants was high (85%) when tested soon after damage but decreased to 40% 1 h after damage. We also examined whether undamaged leaves from a damaged plant attracted tachinid flies. Undamaged leaves were not attractive when all other leaves on the same plant were damaged, even if damaged for several hours. In addition, the undamaged part of damaged leaves was not attractive. These results indicate that volatiles that attract E. japonica are only released from the damaged parts of leaves and these volatiles gradually decrease as the damaged plant ages.
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  • The search for domestic migration of the white-backed planthopper, Sogatella furcifera (Horváth) (Homoptera: Delphacidae), in Japan
    Akira Otuka, Masaya Matsumura, Tomonari Watanabe
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 379-386
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.379
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    The possible domestic migration of the white-backed planthopper, Sogatella furcifera, in Japan was investigated. The next emigrating generation of immigrants during the Bai-u rainy season was selected for analysis. Four criteria were used to determine whether a migration was domestic: 1) a large catch peak in the net trap in northern Japan, 2) in the trap area, the absence of a preceding generation of catch insects based on the analysis of effective accumulated temperature, 3) suitable air currents for insects to migrate from western to northern Japan, as found by backward trajectory analysis, and 4) the presence of emigrating adults in rice fields in western Japan based on a field survey of the population density. The catch data obtained from a net trap in Akita city, Akita prefecture, from 1980 to 2006 showed four clear peaks exceeding 1,000 insects per day, and only one of these, occurring in early August 1987, was found to meet all criteria. The weather pattern was a low-pressure system in the Japan Sea moving northeastward, with a windy region from western to northern Japan. The possible effect of domestic migration in early August on rice crops in northern Japan was discussed.
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  • Trade-off between dispersal and reproduction in Aphelenchoides besseyi (Nematoda: Aphelenchoididae) harbored in Oryza sativa seeds in paddy fields
    Shigeru Hoshino, Katsumi Togashi
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 387-396
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.387
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    The white tip nematode, Aphelenchoides besseyi, is a seed-borne ectoparasite of rice, Oryza sativa. Population parameters were compared with relation to seed specific gravity between infested and non-infested paddy fields to evaluate the effect of a nematode infestation on dispersal and survival of both host plant and nematode. When seeds from infested and non-infested paddy fields were floated on water, the proportion of light seeds (identified by floating at the water surface) was greater for infested field than for non-infested field. Light seeds showed smaller mean swelling, developed a smaller proportion of seminal roots, and required longer to produce the roots than did the heavy seeds from infested and non-infested fields. Nematode mortality was greater in light seeds than in heavy seeds. These results suggested that there was a trade-off between both the dispersal and competition of rice seeds and between dispersal and reproduction of nematodes harbored in the seed. Intriguingly, light seeds from infested fields showed a larger mean degree of swelling than did those from non-infested fields and light seeds harboring many nematodes had a well-developed endosperm, suggesting a host manipulation by the nematode.
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  • Media for conidial production of the entomopathogenic fungus, Fusarium coccophilum (Anamorphic fungi: Phialosporae)
    Mitsuaki Shimazu
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 397-402
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.397
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    Culture media were developed for the mass production of conidia of Fusarium coccophilum, isolated from the scale insect Comstockaspis macroporana. Three isolates were cultured on each of PDA, SDAY and water agar, but none of these produced adequate amounts of conidia for application. Using an isolate F-2965, conidial productions on improved media were compared. Among the 13 media tested, conidial production was poor on nutrient rich media, such as PDA, MEA, CMA and Sabouraud's saccharose agar. Medium No. 4, which consisted of peptone, yeast extract and starch, produced the highest conidial yield, followed by medium No. 3 with half starch and medium No. 1 with saccharose substituted for starch. However, media containing starch as the carbon source were highly viscous and difficult to prepare as agar plates. On the other hand, medium No. 1, which contained saccharose instead of starch, was easy to prepare and conidial yield did not significantly differ with medium No. 3. Thus, medium No. 1 was the most practical and had the highest conidial yield among the media tested, with 3.4×104 conidia/cm2 plate.
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  • Expression of the dopamine transporter in the brain of the honeybee, Apis mellifera L. (Hymenoptera: Apidae)
    Shogo Nomura, Jun-ichi Takahashi, Tetsuhiko Sasaki, Tadaharu Yoshida, ...
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 403-411
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.403
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    The dopamine transporter (DAT) is located on the presynaptic membrane of dopaminergic terminals and recovers the released dopamine from synaptic clefts. Therefore, its expression level is expected to reflect the activity of dopaminergic neurons. We identified the honeybee ortholog of dat (Amdat) and measured its expression levels in honeybee brain by reverse transcription real-time quantitative polymerase chain reaction. Worker honeybees change their tasks from nursing to foraging in an age-dependent manner, and Amdat transcript levels in their brains were found to increase with age. Furthermore, the expression level was significantly higher in precocious foragers than in nurses of the same age, suggesting that Amdat expression is related to task shifts. In queens, Amdat expression levels decreased after a mating flight. Amdat expression in drone honeybees increased with age. Our data suggest that dopamine pathway activity is correlated with the behavioral activity of honeybee.
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  • Fertility restoration of cryopreserved semen by hyper ratio of apyrene sperm in Bombyx mori
    Yoko Takemura, Ken Sahara, Yuji Mochida, Akio Ohnuma
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 413-417
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.413
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    Feasible methods for sperm cryopreservation and subsequent artificial insemination are urgently needed to maintain silkworm genetic resources with less laborious work and space cost. We have discovered that loss of the fertilizing ability of cryopreserved diploid (p50) semen was restored by the addition of either fresh or frozen apyrene sperm from triploid donors. To decrease usage of the amount of stored diploid semen, we monitored the effective ratio of cryopreserved p50 semen and apyrene sperm from triploid males to restore fecundity. Restoration of the fertilizing ability of cryopreserved p50 semen was kept by roughly one fourth decrease of the amount by increasing the apyrene sperm ratio. Because semen collection from diploid males requires skillful and careful techniques, decreasing the amount of cryopreserved semen may practically save laborious work. It may also contribute to successful restoration of fertilization with a small amount of semen from a small number of individuals.
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  • Study of destruxin B and tea saponin, their interaction and synergism activities with Bacillus thuringiensis kurstaki against Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)
    Muhammad Rizwan-ul-Haq, Qiong Bo Hu, Mei Ying Hu, Guohua Zhong, Qunfan ...
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 419-428
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.419
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    This study reveals the individual and synergistic effects of destruxin B (DB) (mycotoxin from Metarhizium anisoplae), tea saponin (Ts) and Bacillus thuringiensis (Bt) against Spodoptera exigua. DB, Ts and Bt reduced the growth of neonate larvae by up to 91.30, 89.17 and 77.17%. EC50 values of DB against 4th and 5th instars were 0.17 and 0.22 mg ml−1, 0.35 and 0.41 mg ml−1 against 4th and 5th instars for Ts and 0.0031 and 0.0035 mg ml−1 after being treated with Bt. The synergism of DB and Ts with Bt resulted in the increased efficiency of these chemicals as mortality percentages significantly increased up to 94.2% with DB+Ts+Bt followed by DB+Bt with 91.99% and were significantly higher than individual treatments of Bt 65.81% and Ts 76.66%. Nutritional analysis revealed the increased toxicity of DB and Ts in combination with Bt, but DB+Bt showed higher efficiency with minimal relative consumption rate (RCR) 2.69 mg/mg/day, relative growth rate (RGR) 1.33 mg/mg/day and efficiency of conversion of ingested food (ECI) 35.77%, respectively. Changes in antioxidant enzymes, superoxidase dismutase (SOD) and catalases (CAT), were noticed to some extent over different exposure times in all treatments. The highest SOD activity was observed in individual DB treatment, while individual Bt treatment caused the highest variation in CAT values. In all treatments, SOD and CAT values fell sharply on the final day except for individual Bt treatment, with which the values were relatively stable on the final day.
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  • Northward range expansion by Nezara viridula (Hemiptera: Pentatomidae) in Shikoku and Chugoku Districts, Japan, possibly due to global warming
    Junichi Yukawa, Keizi Kiritani, Tetsuo Kawasawa, Yoshimitsu Higashiura ...
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 429-437
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.429
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    Field surveys and light trap catches of Nezara viridula and N. antennata (Hemiptera: Pentatomidae) in Shikoku and Chugoku Districts, Japan showed that N. viridula is now distributed along the northern coastline of Shikoku District, and in Yamaguchi Prefecture, and along the northern coastline of Shimane Prefecture, south of Izumo, Chugoku District. The present data together with previous reports suggest that the northward range expansion of N. viridula is possibly due to global warming because the monthly mean temperature for January in newly invaded areas has exceeded 5°C in recent years, for example, since 1986 in Fukuoka, below which the winter mortality of N. viridula adults becomes higher. Around the northern limit of N. viridula in Shimane Prefecture, it was not found in April–August 2008 because the monthly mean temperature for January 2008 fell below 5°C, below which the winter mortality of N. viridula becomes higher. Thus, the northern limit retreated depending on winter temperature. We confirmed the absence of N. viridula from 1979 until August 2008 in Izumo, Shimane Prefecture, and in 2007–2008 in Tottori Prefecture. Most areas along the southern seacoast in Shikoku District were occupied only by N. viridula, suggesting that it has replaced N. antennata by interspecific mating. In the Chugoku District, no area was occupied only by N. viridula, but it was more abundant than N. antennata in southern Yamaguchi Prefecture, indicating that N. viridula is now replacing N. antennata in that area.
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  • Improvement of artificial diet for aphidophagous syrphids, Episyrphus balteatus (de Geer) and Eupeodes bucculatus (Rondani) (Diptera: Syrphidae)—Additional effects of fatty acids and preservatives
    Hideki Iwai, Keiko Niijima, Mitsuo Matsuka
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 439-446
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.439
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    The addition of fatty acids to drone honeybee brood powder (DP)-containing gel diet was found to improve larval development of aphidophagous syrphids, Episyrphus balteatus and Eupeodes bucculatus (Diptera: Syrphidae). When each fatty acid was added singly to the basic diet, the emergence rate was higher than on unsupplemented diets in E. bucculatus. In particular, the addition of oleic acid and linoleic acid improved the emergence rate and adult body size. The combination of both acids was most effective for the development of E. bucculatus. Two gel diets, consisting of DP, oleic acid, and linoleic acid at specific rates, were designed for young and old larvae, respectively; diet agar concentration was also specified. When these diets were provided to larvae of both species, these emergence rates exceeded 90% and adult body sizes were equivalent to aphid-fed controls. Three preservatives to stabilize diets were tested: propionic acid, sodium benzoate, and methyl paraben. Propionic acid (0.5%) had no effects on E. balteatus, but the emergence rate of E. bucculatus was much inferior to the control diet even at a concentration of just 0.1%.
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  • Feeding habits of the diving beetle larvae, Cybister brevis Aubé (Coleoptera: Dytiscidae) in Japanese wetlands
    Shin-ya Ohba
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 447-453
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.447
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    A number of descriptive reports suggest that Cybister larvae feed on tadpoles, fish, and aquatic insects; however, no quantitative study on their feeding habits has been reported. In order to elucidate the feeding ecology of C. brevis larvae, field observations and laboratory experiments were carried out. In the field, all C. brevis larvae fed on invertebrates, such as insects and isopoda, but did not eat vertebrates, such as fish and anuran larvae. A rearing experiment demonstrated that all C. brevis larvae provided with tadpoles died. Larvae provided with Odonata nymphs had a longer total body length than larvae reared with a mixture of tadpoles and Odonata nymphs. In addition, larvae of C. brevis could search for and eat motionless Odonata nymphs, but all larvae died from starvation when they were supplied with motionless tadpoles. These results suggested that C. brevis larvae mainly preyed upon invertebrate animals and did not eat vertebrate animals, such as tadpoles and fish.
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  • An analysis of Thysanoptera associated with citrus flowers in Antalya, Turkey: Composition, distribution, abundance and pest status of species
    İlyas Tekşam, İrfan Tunç
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 455-464
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.455
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    Composition, distribution, abundance and pest status of thrips species associated with citrus flowers in Antalya, Turkey was investigated in 2006 and 2007. The survey revealed 36 thrips species. The most common and abundant species in descending order were: Thrips major Uzel, Frankliniella occidentalis (Pergande), T. tabaci Lindeman, T. meridionalis (Priesner), T. angusticeps Uzel and Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae). The thrips fauna was predominated by T. major being found in 84% of the samples and constituting 51% of the specimens. F. occidentalis was the second most common and abundant species which was present in 55% of the samples and representing 22% of the specimens. The other four major species were detected in 12–28% of the samples and had a share of 4–6% in the total number of specimens. Average number of thrips per flower ranged between 0.26 and 0.55 depending on the citrus species. Proportion of scarred fruits ranged between 0.8 to 2.4%. Only P. kellyanus is known as a citrus pest and currently is less common and abundant than in those countries where it causes crop losses. These findings in Turkey do not provide any clear evidence concerning the country of origin of P. kellyanus.
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  • Life cycle of the apple snail Pomacea canaliculata (Caenogastropoda: Ampullariidae) inhabiting Japanese paddy fields
    Kazuhiro Yoshida, Kazuo Hoshikawa, Takashi Wada, Yoichi Yusa
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 465-474
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.465
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    The life cycle of the apple snail Pomacea canaliculata was monitored over 2- and 1-year periods in Nara (cold district) and Kumamoto (warm district), respectively. The life cycles were similar in both districts: most hatchlings appeared after August, and although some had grown to ≥20 mm by autumn, the majority of juveniles remained <20 mm. The survival rate over winter was very low (<1%) in Nara, and moderately low (9%) in Kumamoto. After winter, survivors grew rapidly with low mortality, reproduced actively in summer, and most died during the following winter. The survival rate during mid-term drying (drying of fields for about 2 weeks in summer) in Nara was high (ca. 90%) in both years. In Nara, snail density after winter decreased to 1/43 of that in Kumamoto, but survivors in Nara grew larger and laid more eggs. Due to these effects, egg density in July, and also snail density in September, in Nara recovered to ca. 1/3 of that in Kumamoto.
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  • Characterization of brown planthopper strains based on their differential responses to introgressed resistance genes and on mitochondrial DNA polymorphism
    Muhammad Naeemullah, Prem N. Sharma, Muhammad Tufail, Naoki Mori, Masa ...
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 475-483
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.475
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    Biotypes cause a serious problem in controlling brown planthopper (BPH), Nilaparvata lugens Stål (Homoptera: Delphacidae). We characterized four BPH strains, which were collected in different localities in Japan and maintained by random mating within each strain for different periods. The virulence of the BPH strains was evaluated based on their postembryonic development on susceptible and resistant rice lines and inhibition of rice seedling growth. Two single resistance gene introgression lines, “Norin-PL3 (Bph1 carrier)” and “Norin-PL4” (bph2 carrier), and a pyramided line in which both genes were combined were used with a susceptible japonica recurrent parent “Tsukushibare” as a control. Sequence comparison of the mitochondrial cytochrome oxidase-I (COXI) gene was also performed in the characterization. The four BPH strains were classified into two or three groups with unique virulence spectra. The oldest strain showed avirulence against both introgressed resistance genes, while the three younger strains showed strong virulence against one or both genes. The different virulence spectra suggested the sequential adaptation of these BPH strains to the two resistance genes. Pyramiding of the resistance genes had no additive effect on rice seedlings carrying them even against avirulent and less-virulent BPH strains.
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  • Differences in timing of the emergence of the overwintering generation between rice and water-oats populations of the striped stem borer moth, Chilo suppressalis (Lepidoptera: Crambidae)
    Keiichiro Matsukura, Sugihiko Hoshizaki, Yukio Ishikawa, Sadahiro Tats ...
    Article type: Regular Paper
    2009 Volume 44 Issue 3 Pages 485-489
    Published: August 25, 2009
    Released on J-STAGE: December 16, 2009
    DOIhttps://doi.org/10.1303/aez.2009.485
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    The striped stem borer moth, Chilo suppressalis, consists of two host-associated populations: a rice-feeding population and a water-oats-feeding population. We investigated the seasonal occurrence of each population using sex pheromone traps in paddy fields and adjacent water-oats vegetation. Trapped males were individually classified into their respective populations by morphometric analyses of genitalia. Although the first flight of the water-oats population was long, with 1 to 3 poorly resolved peaks during April to June, that of the rice population was much shorter, with a sharp peak in early June. This result supports previous observations that adults of the overwintering generation of the water-oats population occur about two months earlier than those of the rice population; however, it is uncertain how this difference enhances reproductive isolation between the two populations because the occurrence overlaps.
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