Infectivity of Four Species of Nematodes (Rhabditoidea: Steinernematidae, Heterorhabditidae) to the Asian Longhorn Beetle, Anoplophora glabripennis (Motchulsky) (Coleoptera: Cerambycidae)

Four species of entomopathogenic nematodes, Steinernema carpocapsae , Heterorhabditis bacteriophora , H. indica and H. marelatus , were tested for their ability to kill and reproduce in larvae of the Asian longhorn beetle, Anoplophora glabripennis (Motchulsky). The larvae were permissive to all four species but mortality was higher and production of infective juveniles was greater for S. carpocapsae and H. marelatus . The lethal dosage of H. marelatus was determined to be 19 infective juveniles for second and third instar larvae and 347 infective juveniles for fourth and fifth instar larvae. H. marelatus infective juveniles, applied via sponges to oviposition sites on cut logs, located and killed host larvae within 30 cm galleries and reproduced successfully in several of the larvae.     

Stem cell research in Asia: A critical view

Stem cell research stands as a high‐priority field in many countries across the Asia‐Pacific region, and the past decade has seen remarkable investment into facilities and programs intended to increase competitiveness in the drive to find clinical applications. In the years roughly framed by Korean cloner Woo‐Suk Hwang's meteoric ascent and fall, speculation was rampant that Asia was poised to overtake the West in this field of science. But that potential remains unfulfilled. In this article, I will look at some of the deficits in infrastructure and governance that underlie the East–West stem cell gap, and suggest a number of measures that might be taken to remedy them. J. Cell. Biochem. 107: 853–856, 2009. © 2009 Wiley‐Liss, Inc.     

Allopatric speciation of Meteterakis (Heterakoidea: Heterakidae), a highly dispersible parasitic nematode,in the East Asian islands

To clarify how the species diversity of highly dispersible parasites has developed, molecular phylogenetic analyses of Meteterakis spp., multi-host endoparasitic nematodes of reptiles and amphibians from the East Asian islands, were conducted. The results demonstrated the existence of two major clades, the J- and A-groups, with exclusive geographic ranges that are discordant with the host faunal province. However, diversification within the J-group was concordant with the host biogeography and suggested co-divergence of this group with vicariance of the host fauna. In contrast, the phylogenetic pattern within the A-group was discordant with host biogeography and implied diversification by repeated colonization. In addition, the mosaic distribution pattern of a J-group and an A-group species in the Japanese Archipelago, along with comparison of population genetic parameters and the genetic distance from their closest relatives, suggested the initial occurrence of a J-group lineage followed by exclusion in the western part of this region caused by invasion of an A-group lineage. Thus, the present study suggested that the species diversity of highly dispersible parasites including Meteterakis is formed not only by co-divergence with host faunal vicariance but also by peripatric speciation and exclusive interactions between species.     

Environmental conditions for Diaphorina citri Kuwayama (Hemiptera: Liviidae) take‐off

Environmental factors that influence flight activity of Diaphorina citri Kuwayama (Hemiptera: Liviidae) may have implications for Huanglongbing spread and management. In this work, four studies were conducted to evaluate the effect of environmental conditions on D. citri take‐off. In the first, insects were transferred to sweet orange seedlings and confined inside an acrylic cage to verify the take‐off periodicity and the effect of environmental factors on this process. In the second, take‐off temperature threshold was estimated by recording the number of insects that initiated flight from a platform when subjected to gradual temperature increases from 15 to 39°C. In the other studies, we evaluated the effect of different photoperiods and temperature regimes (third study) and of constant temperatures (fourth study) on the propensity for D. citri flight. Insects were confined in clear plastic bottle cages with tubes of 50 ml placed on the cab, to collect emerged adults that initiated flights. Results showed that a small portion of the tested population (maximum 10%) tends to take off from plants and this behaviour is more prevalent in the afternoon (14:00–16:00 h), coinciding with daytimes of lower humidity and higher thermal amplitude. Adults that were submitted to lower temperatures (18°C) and short light periods (10 h) showed less propensity to flight. In contrast, at constant 27°C, the insects were more prone to flight, and this result was confirmed when individuals were submitted to increases in temperature, indicating that 27.14°C is the take‐off temperature threshold of D. citri. Results show that temperature plays an important role in the flight activity of D. citri and suggest that control measures of the insect may be more effective in the morning and in temperatures below 27°C, when the probability to take off from a host is lower.     

Effects of temperature on biology and life table parameters of the Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae)

The development, survivorship, longevity, reproduction, and life table parameters of the Asian citrus psyllid, Diaphorina citri Kuwayama were evaluated at 10°C, 15°C, 20°C, 25°C, 28°C, 30°C and 33°C. The populations reared at 10°C and 33°C failed to develop. Between 15°C and 30°C, mean developmental period from egg to adult varied from 49.3 days at 15°C to 14.1 days at 28°C. The low‐temperature developmental thresholds for 1st through 5th instars were estimated at 11.7°C, 10.7°C, 10.1°C, 10.5°C and 10.9°C, respectively. A modified Logan model was used to describe the relationship between developmental rate and temperature. The survival of the 3rd through 5th nymphal instars at 15–28°C was essentially the same. The mean longevity of females increased with decreasing temperature within 15–30°C. The maximal longevity of individual females was recorded 117, 60, 56, 52 and 51 days at 15°C, 20°C, 25°C, 28°C and 30°C, respectively. The average number of eggs produced per female significantly increased with increasing temperature and reached a maximum of 748.3 eggs at 28°C (P<0.001). The population reared at 28°C had the highest intrinsic rate of increased (0.199) and net reproductive rate (292.2); and the shortest population doubling time (3.5 days) and mean generation time (28.6 days) compared with populations reared at 15–25°C. The optimum range of temperatures for D. citri population growth was 25–28°C.     

Losses of soil organic carbon under wind erosion in China

Soil organic carbon (SOC) storage generally represents the long‐term net balance of photosynthesis and total respiration in terrestrial ecosystems. However, soil erosion can affect SOC content by direct removal of soil and reduction of the surface soil depth; it also affects plant growth and soil biological activity, soil air CO₂ concentration, water regimes, soil temperature, soil respiration, carbon flux to the atmosphere, and carbon deposition in soil. In arid and semi‐arid region of northern China, wind erosion caused soil degradation and desert expansion. This paper estimated the SOC loss of the surface horizon at eroded regions based on soil property and wind erosion intensity data. The SOC loss in China because of wind erosion was about 75 Tg C yr^?1 in 1990s. The spatial pattern of SOC loss indicates that SOC loss of the surface horizon increases significantly with the increase of soil wind erosion intensity. The comparison of SOC loss and annual net primary productivity (NPP) of terrestrial ecosystem was discussed in wind erosion regions of China. We found that NPP is also low in the eroded regions and heavy SOC loss often occurs in regions where NPP is very small. However, there is potential to improve our study to resolve uncertainty on the soil organic matter oxidation and soil deposition processes in eroded and deposited sites.     

Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), and huanglongbing disease do not exist in the Stapleton Station area of the Northern Territory of Australia

Abstract  A series of specimens of the Asian citrus psyllid, Diaphorina citri , collected from the Northern Territory (NT) in 1915 was recently rediscovered in the Natural History Museum, London. Surveys were conducted in 2002 on suitable hosts in the locality of the 1915 collections to see if the infestation had persisted. These failed to detect either D. citri or the bacterium that it transmits and that causes huanglongbing disease in citrus. It is presumed that D. citri was eradicated fortuitously by the removal of all citrus plants above latitude 19°S during an eradication program for citrus canker in the NT from 1916 until 1922.     

Dispersal and influences on movement for Anoplophora glabripennis calculated from individual mark-recapture

We conducted an individual mark‐release‐recapture experiment on the beetle, Anoplophora glabripennis Motchulsky (Coleoptera: Cerambycidae). This invasive beetle has been introduced from Asia to Europe and North America and poses a serious threat to several important species of tree. Eradication efforts may benefit from knowledge of dispersal behaviour. Trees were cut and held to determine emergence rate of A. glabripennis. Unique marks were painted onto 912 beetles released into a group of 165 trees in Gansu, China. Data on subsequent sightings of beetles were used in a truncated diffusion model to calculate flight distances. Characteristics of the trees and climatic information were used in statistical tests for influence on movement. A total of 2245 sightings of beetles were observed and 29% of marked beetles were resighted. The scanning technique using binoculars was 90% effective in finding beetles and provided 81% accuracy for determining the sex of the beetles. Experimental manipulation of density quantified how A. glabripennis congregated on unoccupied trees and were repulsed from crowded hosts. The seasonal emergence rate of adults declined exponentially from July 20 to August 5. The results suggested A. glabripennis fly to nearby host trees at a rate of 34% per day. Median flight distance was estimated at 20 m per day. Statistical analysis with a generalized linear model tested the beetle's propensity to leave a tree and distance of flight. Generally, beetle movement showed a significant response to beetle density, weather conditions, beetle size, and tree size, in that order. The techniques developed here improve on previous recapture techniques to quantify dispersal and can be useful for analysing populations of other organisms.