Herbivorous insect species in the tree canopy of a relict South African forest

Abstract.

• 1 The herbivorous insects on twelve species of evergreen broadleafed trees were repeatedly sampled over a period of 11 months in a small relict forest on the east coast of South Africa. This extraordinarily speciose forest patch has an unusually high proportion of endemic tree species, some of which are extremely rare.
• 2 The insect herbivore fauna (number of species) seems to be markedly depauperate compared to that reported on native, broadleafed trees from other parts of the world. Some possible reasons for this are discussed.
• 3 The total number of herbivorous insect species on each tree species was strongly correlated with the local relative abundance of the host plant species.
• 4 There was no relationship between the total number of insect herbivore species on each tree species and the relative taxonomic isolation of the trees. The proportion of seemingly unique (= specialist) herbivorous insect species (i.e. those that occurred on one tree species only) was greatest on taxonomically isolated trees.
• 5 A fundamental deficiency in the interpretation of the data in this study, and of many other similar studies that report on the number of insect species on plants, is discussed, namely the lack of clarity on the closeness of the association between individual insect herbivore species and their respective host plants.

     

Diagnostic molecular markers of six lepidopteran insect pests infesting apples in Korea

Two molecular identification techniques for differentiating six lepidopteran pests infesting apples in Korea are presented. These six species include two internal fruit feeders (Grapholita molesta and Carposina sasakii), two leaf rollers (Adoxophyes sp. and Archips breviplicanus) and two leaf miners (Phyllonorycter ringoniella and Lyonetia prunifoliella). All species occur until near harvest and reduce apple production. A 489 bp fragment of mitochondrial cytochrome oxidase subunit I (COI) was sequenced in these six species. The sequence was used to select species-specific restriction enzyme sites and to design diagnostic polymerase chain reaction (PCR) primers, resulting in the development of restriction fragment length polymorphism (RFLP)-PCR and diagnostic PCR. These methods were reliable and rapid in the identification of these six species.     

Effects of meteorological factors and global warming on rice insect pests in Korea

We examined the occurrence patterns of insect pests in paddy fields using a self-organizing map (SOM) and the influence of meteorological factors on these patterns. Data for nine insect pests and three meteorological factors were collected on the Korean nationwide scale from 1992 to 2008. The SOM analysis was based on annual mean densities of each pest species in eight regions. We classified the samples into five clusters (I–V) to display the spatial and temporal changes in the insect pests' occurrences. Clusters I and II included samples collected before 2000; clusters III and IV included samples collected after 2000. The density of Scotinophara lurida was in the lowest range in clusters I and II, and Lissorhoptrus oryzophilus exhibited higher densities in clusters III and IV. Seasonal temperature, humidity, and precipitation were significantly different among clusters, indicating that these factors play a key role in population dynamics and the occurrence of insect pests. The occurrence area of the insect pests was expected to increase with elevated air temperature influenced by global warming based on the IPCC (Intergovernmental Panel on Climate Change) A1B scenario. This study suggests that gathering data on temporal and spatial variations in pest populations and changes in occurrence rate under the effects of global warming can provide insight into the factors governing the population-environment relationships, as well as the information needed for future pest management.     

DNA content in South American endemic species of Lathyrus

The genome size was surveyed in 13 Notolathyrus species endemic to South America by flow cytometry and analyzed in an evolutionary and biogeographic context. A DNA content variation of 1.7-fold was registered, and four groups of species with different DNA content were determined. Although, the 2C values were correlated with the total chromosome length and intrachromosomal asymmetry index (A₁), the karyotype formula remained almost constant. The conservation of the karyotype formula is in agreement with proportional changes of DNA in the chromosome arms. Species with annual life cycle and shorter generation time had the lowest DNA content and the data suggest that changes in DNA content involved reductions of genome size in the perennial to annual transitions. The variation of 2C values was correlated with precipitation of the coldest quarter and, to some extent, with altitude. Additional correlations with other variables were observed when the species were analyzed separately according to the biogeographic regions. In general, the species with higher DNA content were found in more stable environments. The bulk of evidence suggests that changes on genome size would have been one of the most important mechanisms that drove or accompanied the diversification of Notolathyrus species.     

Ecological species groups in forest communities in South Belgium

Cluster analysis, correspondence analysis and the method of ecological profiles were used to determine and characterize ecological species groups in woodlands in South Belgium. Two data sets were used, one composed of 260 relevés, the other of 130 relevés with soil analyses (A1). Correspondence analysis points out the most important factors influencing the floristic composition of the stations.     

Spatio-temporal change in forest cover and carbon storage considering actual and potential forest cover in South Korea

This study analyzes change in carbon storage by applying forest growth models and final cutting age to actual and potential forest cover for six major tree species in South Korea. Using National Forest Inventory data, the growth models were developed to estimate mean diameter at breast height, tree height, and number of trees for Pinus densiflora, Pinus koraiensis, Pinus rigida, Larix kaempferi, Castanea crenata and Quercus spp. stands. We assumed that actual forest cover in a forest type map will change into potential forest covers according to the Hydrological and Thermal Analogy Groups model. When actual forest cover reaches the final cutting age, forest volume and carbon storage are estimated by changed forest cover and its growth model. Forest volume between 2010 and 2110 would increase from 126.73 to 157.33 m3 hm-2. Our results also show that forest cover, volume, and carbon storage could abruptly change by 2060. This is attributed to the fact that most forests are presumed to reach final cutting age. To avoid such dramatic change, a regeneration and yield control scheme should be prepared and implemented in a way that ensures balance in forest practice and yield.     

The status quo of invasive alien insect species and plant quarantine in Korea

The recent increase in agricultural commodities from abroad and travelers due to the economic growth and globalization in Korea has resulted in an increase in invasive alien insect species establishing in Korea. When “alien” is defined as species introduced after the beginning of the Greater Korean Empire Era (1897), 171 insect species are considered invasive alien species. On average, 0.85 alien insect species have become established each year for the last 40 years, and 76.6% of the alien insect species are economic agricultural pests. The annual invasion rate and the pest interceptions from imported cut flowers, planting material, and vegetables have been increasing rapidly. Traveler's baggage is an important pathway for fruit flies. Most of the alien pests that were first found in Japan were confirmed in Korea at least 3 years later until the 1990s, but the pattern has been reversed since the 2000s. Thus, continuous information sharing with neighboring countries such as Japan and China is needed to develop a system for early detection and prompt action against invading insect species. Thus, we introduce and summarize the present status of invasive alien insect species in Korea.     

海南特有种东方琼楠种群结构特征

为探讨海南特有种东方琼楠(Beilschmiedia tungfangensis)种群结构特征,在海南尖峰岭林区设置20.4hm2样地,从种群径级结构、静态生命表、存活曲线、空间分布格局等方面进行分析。结果表明:1)东方琼楠种群径级分布呈倒"J"型,为增长型种群;2)在第Ⅲ级(DBH:10～15cm)时生命期望值最高,向大龄级和小龄级呈递减趋势;3)存活曲线接近DeeveyⅢ型,呈凹型;死亡率曲线和消失率曲线呈"V"型;4)不同分析方法均表明该种群呈聚集分布,且聚群强度较大;5)聚块性指数随径级呈"正余弦"变化。     

The relative injuriousness of insect pests of cotton in the Namoi Valley,New South Wales

The sequence and relative injuriousness of insect pests was studied for three successive years in unsprayed cotton of the Namoi Valley. Heliothis punctigera Wallengren, the native budworm, and to a lesser extent H. armigera (Hübner), the cotton bollworm, prevented the setting of full crops by destroying buds and bolls. After setting, high proportions of bolls were injured by Earias huegeli Rogenhofer, the rough bollworm. Incidental damage was caused to seedlings by Thrips imaginis Bagnall, the plague thrips, and lo leaves by Anomis flava Fabricius, the cotton looper, and by Austracris guttulosa (Walker), the spur-throated locust. In commercial crops, pest control must rely on the use of broad-spectrum insecticides: H. armigera is currently resistant to several of these, and has become the principal species in the local population of cotton pests. A number of enviromental features impede the natural control of pests in the southerly areas where cotton is now produced. In comparison to the older dryland cropping practised in central Queensland, a higher yield is necessary to cover the production costs of irrigated cotton; a shorter growing season prevents the plants from compensating effectively for insect damage and the natural enemies of cotton pests are less abundant and less active.     

我国林业重大害虫松毛虫的灾害研究进展

我国松毛虫种类丰富,已报道27种,其中6种频繁暴发,年危害松林面积达200万hm2以上、经济损失数亿元。松毛虫灾害研究可以为综合治理松毛虫提供重要的理论依据与相关技术。近年来,我国在影响松毛虫种群发生的关键性因子分析、性信息素的研究与开发利用、松树挥发性物质的成分鉴定及其对寄生蜂或寄生蝇的定位作用、卫星遥感监测技术等方面的研究取得了较大进步,但缺少系统性的归纳总结。为此,文章就近些年来我国在松毛虫灾害机制与暴发机理研究、治理现状与技术措施等方面进行综述,展望今后我国松毛虫治理研究工作的重要方向和趋势。     

Tree growth and competition in a post-logging Quercus mongolica forest on Mt. Sobaek, South Korea

Secondary woodlands in South Korea cover most mountains from low to middle elevations. While general patterns of forest succession are well understood, little is known about mechanisms of stand recovery after disturbance. We examined the spatio-temporal variations in establishment, growth, size inequality, and mode of competition among trees in a 50-year-old post-logging Quercus mongolica-dominated stand. We further compared the growth and stem allometry of single trees, presumably of seed origin, with multi-stemmed trees resprouting from stumps. Q. mongolica formed the upper canopy 16–22 m tall, 88.3% of total stand basal area, and 36.2% of total stem density, with most trees established during the first post-logging decade (51.2% were resprouts). During the first three decades, the Q. mongolica recruits grew exponentially, and disproportionately more in diameter than few older reserved trees left after the last cutting. This substantially decreased size inequality. The reverse trend was observed from 1994 to 2004: larger trees grow more, indicating an increasing asymmetry of competition for light. Neighborhood analysis revealed that when target trees had more or larger neighbors, their exponential phase of growth was reduced and maximum size was decreased. After the 50 years of stand development, more than 70% of Q. mongolica showed growth decline as a result of competitive stress, and mortality was about 30%, concentrated in smaller size classes. Compared to single stems, resprouts within clones do not seem to compete less asymmetric as might be expected based on studies of clonal herbaceous plants and physiological integration within genets. As Q. mongolica was also negatively affected by competition from woody species currently prevailing in the lower tree stratum (Tilia amurensis, Acer mono, Fraxinus rhynchophylla, Acer pseudosieboldianum), we predict the stand will become increasingly dominated by these more shade-tolerant trees.     

Polymorphism of 6-PGD in South Korea: a new genetic variant 6-PGD Korea

Summary During population genetic studies in Korea a new variant in the 6-phosphogluconate (6-PGD) system preliminary called 6-PGD^Korea was observed.     

Host insect species of Ophiocordyceps sinensis: a review

Ophiocordyceps sinensis (≡ Cordyceps sinensis) is one of the most valued medicinal fungi in China, used for its invigorating effects in strengthening the body and restoring energy. The fungus parasitizes larvae of moths and converts them into sclerotia from which the fungus fruiting body grows. Since the late 1950s, considerable effort has been devoted to the study of host insects related to the fungus. In the present paper, the research history of insect species associated with Ophiocordyceps sinensis is briefly reviewed and an extensive literature survey is presented. Ninety-one insect names, spanning 13 genera, related to host insects of Ophiocordyceps sinensis are investigated. The relationships between the reported insect species and Ophiocordyceps sinensis are analyzed. Fifty-seven of these are considered as recognizable potential host species of the fungus distributed throughout the Tibetan Plateau, whilst eight are considered as indeterminate hosts and 26 as non-hosts. Among the names of recognizable potential host insects, three are invalid (nomen nudum) and require further study. This work provides basic information for management of the insect resources and for the conservation and sustainable use of Ophiocordyceps sinensis.     

Nestedness of bee assemblages in an endemic South American forest: the role of pine matrix and small fragments

We assessed species richness and distribution of the apoidean fauna of the coastal Maulino forest, an endemic and threatened forest in central Chile. Remnant forest fragments are immersed in commercial pine plantations, who act as the habitat matrix. The bee assemblages depict a non-nested structure at the landscape level at times when pine plantations are standing. However, assemblages are nested in the fauna of forest fragments at times when plantations are harvested, suggesting that plantations might be acting as habitat providing connectivity between remnants of Maulino forest. Therefore, the conservation of apoideans might require a landscape level approach to be successful, including partial reliance on plantations.     

Trends in butterfly species richness in response to the peninsular effect in South Korea

Aim The Korean peninsula is elongated in shape and is connected to the Asian continent on the north. The peninsular effect – a decline in species density or richness as a function of distance from the mainland base (towards the distal tip) of a peninsula – was evaluated for plants and animals in different peninsulas. The aims of the present study were to describe the pattern of butterfly species diversity and to determine what factors may be responsible for this pattern along the Korean peninsula. The distribution pattern of butterfly species in South Korea before and after the Korean War was also investigated. Location South Korea (34–38° N, 126–129° E). Methods Forty‐three quadrats, each 1/2° latitude by 1/2° longitude, and three data sets – butterfly distribution data from 1938 to 1950, butterfly distribution data from 1976 to 1999, and the combined data – were analysed. The influence of four variables – latitude, longitude, area and maximum altitude – on each quadrat was investigated using multiple regression analysis. Results and conclusion The analyses revealed a marked peninsular effect: there was a significant positive correlation between butterfly species richness and latitude. Additionally, habitat diversity, expressed as maximum altitude, was significantly correlated with butterfly species richness. I conclude that both the geographical orientation and habitat diversity contribute to butterfly species diversity across South Korea. Comparison of ranges between the older and recent data sets suggests that geographical distributions of several species are dramatically reduced in size. These species may be used for future conservation activities in South Korea.