Distribution pattern of entry holes of the tree-killing bark beetle Polygraphus proximus

Bark beetles attack their hosts at uniform intervals to avoid intraspecific competition in the phloem. Bark texture and phloem thickness also affect bark beetle attacks, and the bark characteristics are not spatially homogeneous; therefore, the distribution patterns of entry holes can demonstrate an aggregated distribution. Polygraphus proximus Blandford (Coleoptera: Scolytinae) is a non-aggressive phloephagous bark beetle that feeds on Far Eastern firs. They have caused mass mortality in Russia and Japan. However, the distribution pattern of entry holes of P. proximus and spatial relationships with bark characteristics have not been studied. Thus, we investigated the distribution pattern of entry holes of P. proximus. The distribution of entry holes was significantly uniform in most cases. As the attack density increased, an aggregated distribution pattern within a short distance (< 4.0 cm) was observed. The rough bark had a significantly higher number of entry holes than the remaining bark. The distribution pattern of entry holes demonstrated a significantly aggregated spatial association with rough bark. Finally, rough bark around knots had significantly thicker phloem than the remaining barks. These suggest that P. proximus may preferentially attack rough bark to reproduce in the thicker phloem under a rough bark surface.

DISPERSION PATTERN OF Helopeltis antonii Signoret (HEMIPTERA:MIRIDAE) ON CASHEW PLANTATION

<p>ABSTRACT</p><p>Helopeltis antonii is one of the major pests in most cashew growingareas in Indonesia. The pest attacks cashew plants in the nursery and alsoin the fields which caused significant damage. Apart of cashew the insectshave a lot of alternate host plants such as tea, cocoa, neem, pepper,mangoes, jamboes, etc. This research was aimed at investigating thedispersion pattern of H. antonii in cashew plantation. The research wasconducted in smallholder cashew plantation in Ngadirejo, Wonogiri,Indonesia from March 2004 to May 2006. The observation of H. antoniipopulation was carried out on 60 sample plants which selectedsystematically in about 2 ha cashew plantation area every two weeks.Distribution analysis using various indices of dispersion and regressionmodels was applied to evaluate the dispersion of H. antonii in cashewplantation. The result shows that variance to mean ratio (s 2 / x ), χ2, Lloydmean crowding, Green’s coefficient of dispersion and Taylor’s power lawindicate aggregated distribution when the population is high duringflushing-flowering seasons of cashew plants, and it indicates regular orrandom distribution when the population is low during post-floweringseasons. The aggregated distribution on cashew plants indicated that thereis a preferency to food sources of the plants and an individual behaviour toaggregate. Therefore, sampling and monitoring H. antonii in cashewplantation should be carried out systematically during flushing-floweringseasonsKey words: Cashew, Anacardium occidentale, pest management,Helopeltis antonii, dispersion, Central Java</p><p>ABSTRAK</p><p>Pola sebaran Helopeltis antonii Signoret (Hemiptera:Miridae) pada pertanaman jambu meteHelopeltis antonii merupakan salah satu hama utama tanamanjambu mete yang ditemukan hampir di setiap area pengembangan mete diIndonesia. Hama ini menyerang tanaman jambu mete sejak pembibitanhingga di lapangan dengan kerusakan yang cukup signifikan. Selain jambumete, serangga ini juga mempunyai banyak inang alternatif antara lain teh,kakao, mimba, lada,mangga, jambu air dll. Penelitian ini bertujuan untukmenentukan sebaran serangga tersebut, khususnya sebaran horizontal padapertanaman jambu mete. Penelitian dilakukan di pertanaman jambu metemilik petani di daerah Ngadirejo, Wonogiri, Indonesia dari Maret 2004sampai Mei 2006. Pengamatan populasi H. antonii dilakukan pada 60tanaman sampel yang dipilih secara sistematik pada area pertanamanjambu mete seluas kurang lebih 2 ha setiap 2 minggu sekali. Hasil analisismenggunakan beberapa indek pengelompokan dan model regresi yaiturasio keragaman terhadap rata-rata (s 2 / x ), χ2,rata-rata pengelompokandari Lloyd, koefisien sebaran dari Green dan hukum kekuatan Taylormenunjukkan penyebaran yang mengelompok jika populasi tinggi selamamusim pembentukan tunas dan pembungaan jambu mete, dan merata atauacak jika populasi rendah sesudah musim pembungaan. Pengelompokan H.antonii pada tanaman jambu mete menunjukkan adanya ketertarikan padaketersediaan makanan pada tanaman jambu mete dan perilaku individuserangga tersebut. Oleh karena itu untuk pengambilan sampel danpengamatan serangga tersebut sebaiknya dilakukan secara sistematis padasaat musim pembentukan tunas dan pembungaan.Kata kunci: Jambu mete, Anacardium occidentale, pengendalian hama,Helopeltis antonii, sebaran, Jawa Tengah</p>

Grazing Altered the Pattern of Woody Plants and Shrub Encroachment in a Temperate Savanna Ecosystem

Ulmus pumila-dominated temperate savanna is an important tree-grass complex ecosystem in the Otindag sand land, northern China. To date, few investigations have been undertaken on the spatial patterns and structure of this ecosystem and its driving factors under different grazing pressures. The objective of our study therefore is to explore whether grazing has affected the population structure/pattern of woody plants and shrub encroachment in a temperate savanna ecosystem. Results indicate that species richness and seedlings decreased with increasing grazing pressure. An increase in grazing pressure did not significantly affect adult-tree density, but it hindered the normal regeneration of U. pumila seedlings, further inducing population decline. U. pumila seedlings had a more significant aggregated distribution than juvenile or adult trees. The adult and juvenile trees had an aggregated distribution at the small scale and a random distribution at the large scale. Shrubs also showed a significant aggregated distribution. No clear effect on the spatial patterns of adult trees was observed; however, there was a noticeable effect for juveniles and seedlings under different grazing pressures. U. pumila seedlings had a positive association with their juveniles and Spiraea aquilegifolia, but a negative association with Caragana microphylla. Shrub encroachment occurred with decreasing grazing pressures. In conclusion, overgrazing led to the decline of U. pumila population, but the decrease in grazing pressure increased shrub encroachment in the temperate savanna ecosystem. Moderate grazing management may be a better way to enhance the stability of U. pumila population and reduce shrub encroachment.

Metazoan parasite of lambari Astyanax altiparanae, collected from the Peixe river, São Paulo, southeast of Brazil

ABSTRACT: In March 2010, 44 specimens of Astyanax altiparanae Garutti & Britski, 2000, commonly known as "lambari do rabo amarelo", collected from the Peixe river in the state of São Paulo, Brazil were analyzed. Out of these 44 fishes, 38 had at least one species of metazoan parasite. Fifteen metazoan parasites species were collected and identified: Urocleidoides trinidadensis , Diaphorocleidus kabatai , Diaphorocleidus orthodusus, Diaphorocleidus sp., Urocleidoides sp., Trinibaculum altiparanae , Gyrodactylus sp., Jainus hexops, Contracaecum sp., Procamallanus (Spirocamallanus) inopinatus, Vaigamus sp., Amplexibranchius bryconis, Ergasilus sp., Zonocotyloides haroltravassossi and Henneguya sp. Six species of parasites presented a prevalence of over 10%. Weight and length of fishes didn't influence the parasitism. All parasites presented an aggregated distribution. The parasite community of Astyanax altiparanae from the Peixe river was characterized as having high richness and low uniformity.