Cellulase in Anoplophora glabripennis adults fed on original host tree species and non-original host trees

Cellulase activities of Anoplophora glabripennis （Motsch.） adults from two host plants （Populus simonii x p pyramidliscr cv. Opera Hsu. and Salix matsudana Koidz） fed on three different host tree species （Acer negundo Linn., S. matsudana Koidz and P simonii x P pyramidliscr cv. Opera Hsu.） were investigated. Enzyme activities of endoglucanase and β-glucosidase in the intestines of the insects were measured. The results show that there are no statistically significant differences in the enzyme activities of endoglucanase between male and female insects from the two host plants fed on three host trees, neither inβ-glucosidase. No statistically significant differences in the enzyme activities of endoglucanase and β-glucosidase were found between males and females from the two plants fed on three host tree species, except that the endoglucanase activity in males from the opera poplar fed on Hankow willow is lower than that fed on ash-leaf maple and opera poplar.

The saproxylic beetle assemblage associated with different host trees in Southwest China

Dead wood is a habitat for many insects and other small animals, some of which may be rare or endangered and in need of effective protection. In this paper, saproxylic beetle assemblages associated with different host trees in the subtropical forests in southwestern China were investigated. A total of 277 species （1 439 specimens） in 36 beetle families were collected from 117 dead wood samples, of which 101 samples were identified and respectively belonged to 12 tree genera. The number of saproxylic beetle species varied greatly among logs of different tree genera, with the highest diversity on logs of Juglans. Generally, broad-leaved trees had a higher richness and abundance of saproxylic species than coniferous trees. Cluster analysis revealed that assemblages from broad-leaved tree genera were generally similar （except for Betula） and assemblages from coniferous trees formed another distinct cluster. The subsequent indicator analysis proposed that there are different characteristic species for different cluster groups of host tree genera. In our study, log diameter has no positive influence on beetle species density. Conversely, comparisons of individual-based rarefaction curves suggested that beetle species richness was highest in the small diameter class both in coniferous and broad-leaved tree genera. With increased wood decay, proportion of habitat specialists （saproxylic beetles living on one tree genus） decreased, whereas proportion of habitat generalists （living on more than three tree genera） increased. The beetle species density was found to be higher in early stages, and decreased in later stages as well. A negative influence of altitude on saproxylic beetle species richness and abundance was detected. It was indicated that different tree genera and altitudes possibly display cross effects in modulating the altitudinal distribution and host preference of the beetles.

Oviposition preference of Anoplophora glabripennis emerging from five host tree species under field conditions

The Asian longhorned beetle （ALB）, Anoplophora glabripennis （Motschulsky） is a polyphagous woodborer of hardwood trees. In order to well understand the oviposition preference of A. glabripennis emerging from different larval host tree species, we selected five common host tree species in the field and evaluated its oviposition preferences. The five host tree species are Acer negundo （AN）, Salix matsudana f. lobato-glandulosa （SM）, Populus nigra L. var. thevestina （Dode） Bean （PN）, P. simonii × P. pyramidalis cv. Opera 8277 （PS） and P. alba var. pyramidalis （PA）. Results show that adult beetles emerging from these five tree species almost have the same oviposition phenomenon. All adult beetles, except those emerging from PS, chewed the highest potential sites and laid most eggs on AN trees. Adult beetles emerging from AN, PN, PS and PA did not chew any sites nor laid any eggs on PA trees. These results showed that adult A. glabripennis emerging from the five host tree species did not show any clear oviposition preference for their larval host tree species in the field but they did present the most obvious preference for AN and the lowest preference for PA.

Cellulase in Anoplophora glabripennis adults emerging from different host tree species

In order to investigate different kinds of cellulase in insect pests, we selected male and female adults of Anoplophora glabripennis （Motschulsky） emerging from four different host species （Populus alba var. pyramidalis, P. nigra var. thevestina （Dode） Bean., P. simonii × P. pyramidliscr cv. Opera 8277 Hsu. and Salix matsudana f. lobato-glandulosa） as our research material. The enzyme activitives of three kinds of cellulase in the intestines of the adult insects were measured. The Cx-cellulase isozymes were detected with a CMC-incorporated polyacrylamide gel. The results show that： there are no statistically significant differences between the enzyme activities of males and females emerging from the different host species. The order of magnitude in activity is： Cx-cellulase 〉 β-glycosidase 〉 C1-cellulase. When the adults emerge from the same host species, there are no statistically significant differences between male and female enzyme activities of β-glycosidase and C1-cellulase, but the enzyme activity of Cx-cellulase of males is clearly higher than that of females. The patterns and migration of Cx-cellulase isozymes of males and females emerging from differ-ent hosts trees are clearly not different, and neither are they different when emerging from the same hosts.

Primary Host Tree Species of the Gypsy Moth Lymantria dispar （Lepidoptera： Lymantriidae）in Hyrcanian Forests

Invasions by exotic insects and diseases are one of the most important threats to the stability and productivity of forest ecosystems around the world. Lymantria dispar （Lepidoptera： Lymantriidae） in Iran was observed for the first time in 1937 by Jalal Afshar in oak forests of the Guilan state region. Since its introduction, gypsy moth has spread to the northern, western and south-western regions of Iran. The largest outbreaks of gypsy moth occurred in the Talesh Oak forests of the Hyrcanian zone in 1975. The gypsy moth is a highly polyphagous folivore species that feeds on over 300 species of woody plants. Among its most preferred hosts are oaks and aspens. Some trees are resistant to the gypsy moth including honey locust, black locust, silver maple, green ash, dogwood, sycamore, horse chestnut, firs, and tulip trees. Defoliation during severe outbreaks alters the appearance of forest habitats and leads to tree mortality and changes in stand composition. This study was conducted during 2008 and 2009 in an effort to determine the primary host tree species that the gypsy moth infests in the Hyrcanian forests of lran. For that purpose all egg masses in the area were counted and conclusively significant differences in defoliation levels among tree species were found. The primary host tree species of gypsy moth in Iran was Persian ironweed, Parrotia persica.

Micro-site Conditions of Epiphytic Orchids in a Human Impact Gradient in Kathmandu Valley, Nepal

We studied distribution and site conditions of epiphytic orchids in a gradient of human interference in Kathmandu valley, central Nepal. The aim was to understand the recent distribution pattern of epiphytic orchids, with respect to (i) the micro-site conditions and (ii) the type and intensity of land use. The occurrence of epiphytic orchids was recorded for a grid with 1.5 km cell size. The cells represent different types and intensities of human impact. Site factors such as bark rugosity, bark pH, diameter at breast height (dbh; 1.3 m) of host trees, exposure to wind and sunlight intensity were recorded. With regard to the species richness and abundance of epiphytic orchids, we compared different human impact categories from very strong human impact (settlement area) to very low human impact (national park). Remote sensing was used for a supervised classification of land cover. Ficus religiosa turned out to be the most important host species for orchids in urban areas, while Schima wallichii and Alnus nepalensis significantly host orchids in the other categories. Both species richness and abundance of epiphytic orchids were significantly higher under very low human impact (forest in national park) and also some remaining patches of primary forest than the other regions. Micro-climate is crucial for orchid populations. Host bark pH, bark rugosity, sunlight intensity and host exposure were significantly different for all human impact categories in order to harbour epiphytic orchid species. Habitats with a mixture of mature trees are suitable and essential for the conservation of viable populations of epiphytic orchids in settled areas. The study reveals that to improve the population size of orchids it is essential for future urban forestry to: (i) Protect old trees as carriers of existing epiphytic orchid diversity, (ii) protect medium old trees to ensure that they may become old trees, (iii) plant new host trees for the future, (iv) plant in groups instead of single isolate trees. Trees should especially be planted in areas where orchids still exist to provide more trees for orchid population enlargement (e.g. along riparian system). Native species should be favoured; the pool of such native host species is wide.