Siberian silkmoth(SSM,Dendrolimus sibiricus Tschetv.)is the most important defoliator of Siberian pine(Pinus sibirica Du Tour)and fir(Abies sibirica Ledeb.)stands.Warming-induced SSM outbreaks are one of the major dri...Siberian silkmoth(SSM,Dendrolimus sibiricus Tschetv.)is the most important defoliator of Siberian pine(Pinus sibirica Du Tour)and fir(Abies sibirica Ledeb.)stands.Warming-induced SSM outbreaks are one of the major driving factors of successions within the taiga zone.It is suggested that climate change impacted the SSM range and life cycle.We analyzed the migration of alpine and northerly SSM outbreak boundaries in Siberia and the impact of the climate variables and topography on the outbreak dynamics.We used time-series scenes(multispectral data,and vegetation indexes EVI and NDII)in combination with field studies,climate variables,and GIS techniques.We found that SSM outbreaks in the area of alpine boundary shifted about 370 m uphill since the mid of 1950.The outbreak onset was promoted by increased dryness and active temperatures and decreased root zone moisture content in the spring-early summer period.The terrain topography strongly affected SSM outbreak onset and dynamics.Initially,the outbreak was located at the middle elevations on the gentle concave southeastern slopes,which are the favorable insect habitats between outbreaks.Then the outbreak expanded uphill and downhill,to steeper slopes,and both concave and convex terrains.Alongside with elevation range expansion,SSM surpassed its northern historical outbreak boundary:the potential outbreaks’boundary moved about 300 km northward.Climate warming contributes to SSM migration into former outbreak free conifer stands located in highlands and at northern latitudes.展开更多
In recent years, numerous actions for sustainable exploitation of forest resources have been undertaken, but few deal with commercialization of forest insects. Several tree based insect products, like wild silk, can b...In recent years, numerous actions for sustainable exploitation of forest resources have been undertaken, but few deal with commercialization of forest insects. Several tree based insect products, like wild silk, can be linked with forest conservation activities to provide livelihood services of different economic scales to forest dependent people. African wild silkmoth, Argema mimosae Boisduval, is one of the forest insects, a moth in the family of Saturniidae producing wild silk, but there is need for definite procedures for extracting silk fibre from its cocoons. This study evaluated physical characteristics of the A. mimosae cocoons and outlined a procedure to extract viable silk fibre for use in silk industry. Cocoons of the A. mimosae were collected from natural forest of Arabuko-Sokoke, Kenya （3020＇ S, 39055＇ E）, and others obtained by semi-captive rearing of the silkmoth larvae. The cocoons of A mimosae were described to be silvery in colour, tough and thick with distinctive perforations on the surface and a prominent valve-like opening with loose filaments at one end. The study recorded 120 min as the optimum boiling time for the cocoons to yield silvery brown silk floss using sodium carbonate （Na2CO3） as the degumming agent. Cocoons boiled in distilled water could not be deflossed into floss, but remained hard and intact, as compared with those of the control, Bombyx mori. This reveals that A. mimosae cocoons can be processed for natural silk fibre production and offer communities adjacent to forests an excellent opportunity to engage in production of natural wild silk.展开更多
基金supported by the Russian Foundation for Basic Research,project nos.18-45-240003 and 18-05-00432。
文摘Siberian silkmoth(SSM,Dendrolimus sibiricus Tschetv.)is the most important defoliator of Siberian pine(Pinus sibirica Du Tour)and fir(Abies sibirica Ledeb.)stands.Warming-induced SSM outbreaks are one of the major driving factors of successions within the taiga zone.It is suggested that climate change impacted the SSM range and life cycle.We analyzed the migration of alpine and northerly SSM outbreak boundaries in Siberia and the impact of the climate variables and topography on the outbreak dynamics.We used time-series scenes(multispectral data,and vegetation indexes EVI and NDII)in combination with field studies,climate variables,and GIS techniques.We found that SSM outbreaks in the area of alpine boundary shifted about 370 m uphill since the mid of 1950.The outbreak onset was promoted by increased dryness and active temperatures and decreased root zone moisture content in the spring-early summer period.The terrain topography strongly affected SSM outbreak onset and dynamics.Initially,the outbreak was located at the middle elevations on the gentle concave southeastern slopes,which are the favorable insect habitats between outbreaks.Then the outbreak expanded uphill and downhill,to steeper slopes,and both concave and convex terrains.Alongside with elevation range expansion,SSM surpassed its northern historical outbreak boundary:the potential outbreaks’boundary moved about 300 km northward.Climate warming contributes to SSM migration into former outbreak free conifer stands located in highlands and at northern latitudes.
文摘In recent years, numerous actions for sustainable exploitation of forest resources have been undertaken, but few deal with commercialization of forest insects. Several tree based insect products, like wild silk, can be linked with forest conservation activities to provide livelihood services of different economic scales to forest dependent people. African wild silkmoth, Argema mimosae Boisduval, is one of the forest insects, a moth in the family of Saturniidae producing wild silk, but there is need for definite procedures for extracting silk fibre from its cocoons. This study evaluated physical characteristics of the A. mimosae cocoons and outlined a procedure to extract viable silk fibre for use in silk industry. Cocoons of the A. mimosae were collected from natural forest of Arabuko-Sokoke, Kenya （3020＇ S, 39055＇ E）, and others obtained by semi-captive rearing of the silkmoth larvae. The cocoons of A mimosae were described to be silvery in colour, tough and thick with distinctive perforations on the surface and a prominent valve-like opening with loose filaments at one end. The study recorded 120 min as the optimum boiling time for the cocoons to yield silvery brown silk floss using sodium carbonate （Na2CO3） as the degumming agent. Cocoons boiled in distilled water could not be deflossed into floss, but remained hard and intact, as compared with those of the control, Bombyx mori. This reveals that A. mimosae cocoons can be processed for natural silk fibre production and offer communities adjacent to forests an excellent opportunity to engage in production of natural wild silk.
