In the southern Algerian Sahara, populations of the desert locust have been monitored during the past 43 years. On a limited study area, the use of remote sensing data from Landsat 7 ETM+ and Terra MODIS, coupled with...In the southern Algerian Sahara, populations of the desert locust have been monitored during the past 43 years. On a limited study area, the use of remote sensing data from Landsat 7 ETM+ and Terra MODIS, coupled with the locust population database, allowed the identification and mapping of solitary desert locust breeding areas during remission periods. These sites are mainly located in wadis and in areas of accumulation/spreading of rainwater. The use of this methodology to all the Algerian Sahara is surely possible in order to improve the preventive management of this pest.展开更多
Detailed aspects of the transition from the solitarious to the gregarious phase in the framework of locust ecology are undoubtedly most important for understanding locust phase polyphenism. Nevertheless, due to obviou...Detailed aspects of the transition from the solitarious to the gregarious phase in the framework of locust ecology are undoubtedly most important for understanding locust phase polyphenism. Nevertheless, due to obvious difficulties in studying the solitarious phase in nature, such information is limited and mostly available from research carried out under laboratory conditions. In the current study, we examined the dispersal patterns of newly hatched locust nymphs in a laboratory setup that simulated seminatural conditions. This was carried out with no previous manipulation of the nymphs other than controlling their parental density. We comparatively tested the spatial distribution of newly hatched nymphs on perches located at different ranges within an emergence arena, and the expected Poisson （random） distribution. Hatchlings were found to disperse among the perches in a pattern significantly different from that expected by random. Irrespective of their parents＇ phase, the observed distributions of all nymphs were clearly clumped, similar or close to those expected for gregarious locusts. It seems that rather than emerging with a parentally derived and predetermined phase, hatchlings have an independent default or innate behavioral state, which reflects at least tolerance if not attraction to conspecifics. The typical phase behavior may later become dominant under the appropriate environmental conditions. These results imply novel perspectives on locust phase transformation, which contribute to our understanding of the formation of locust crowds under field conditions. These should be considered in any rationale for developing a preventative management strategy of locust populations.展开更多
The desert locust, <em>Schistocerca gregaria</em> Forsk. (Orthoptera: Acrididae) is a peculiar insect that exhibits density-dependent phase polyphenism. Gregarious phase enables desert locust to form a lar...The desert locust, <em>Schistocerca gregaria</em> Forsk. (Orthoptera: Acrididae) is a peculiar insect that exhibits density-dependent phase polyphenism. Gregarious phase enables desert locust to form a large groups and mass migrations during which significant crop loss and food security issues may occur. Currently, the most recent upsurge of desert locust is prevailing across Eastern Africa and Southwestern Asia. Usually desert locusts are restricted to regions like semi-arid and arid regions. A super cyclonic storm, namely Amphan originated during May 2020, in the Bay of Bengal of North Indian Ocean has influenced numerous swarms to migrate from the Thar desert region to other parts of India. In this research, satellite data were used to investigate the reasons for this sudden swarm migration. The results that revealed the wind jets passing above the Thar desert region have integrated with the cyclogenesis of Amphan and led to the formation of conduits. The favorable conditions in the conduits include the open sky conditions, air temperature and fresh vegetation availability. Moreover, the wind settings in the conduits have enabled the swarm migrate to follow the downwind facing the sunrays during early mornings for an easy and successful take-off. It is observed that during the take-off session the wind speed at 850 hPa pressure level is mostly double than that of surface wind in both the conduits.展开更多
Although the species Mattiwlomyces terfezioides(≡ Terfezia terfezioides) has been recorded from China several times but it is really rare taxon with important ecological and economic value,the conspecihcity with Euro...Although the species Mattiwlomyces terfezioides(≡ Terfezia terfezioides) has been recorded from China several times but it is really rare taxon with important ecological and economic value,the conspecihcity with European material has never been tested by molecular data.We re-examined three specimens labelled as T.terfezioides,one as T.leonis and one as Terfezia sp.in the herbarium HMAS and obtained five ITS and three LSU sequences.Our morphological observation and DNA sequences show that one specimen(HMAS 83766) labelled as M.terfezioides turns out to be Choiromyces sp.and the other four are M.terfezioides.The ITS and(or) LSU sequences of the Chinese samples are identical with or with 99%similarity to those from the European samples,which fully confirms the presence of M.terfezioides in China.The species is currently known from northern China(Hebei Province,Beijing and Shanxi Province).This study shows that M terfezioides has a Euroasia distribution other than European endemism and such distribution might be explained by the co-occurrence with the potential host tree Robinia pseudoacacia.展开更多
文摘In the southern Algerian Sahara, populations of the desert locust have been monitored during the past 43 years. On a limited study area, the use of remote sensing data from Landsat 7 ETM+ and Terra MODIS, coupled with the locust population database, allowed the identification and mapping of solitary desert locust breeding areas during remission periods. These sites are mainly located in wadis and in areas of accumulation/spreading of rainwater. The use of this methodology to all the Algerian Sahara is surely possible in order to improve the preventive management of this pest.
文摘Detailed aspects of the transition from the solitarious to the gregarious phase in the framework of locust ecology are undoubtedly most important for understanding locust phase polyphenism. Nevertheless, due to obvious difficulties in studying the solitarious phase in nature, such information is limited and mostly available from research carried out under laboratory conditions. In the current study, we examined the dispersal patterns of newly hatched locust nymphs in a laboratory setup that simulated seminatural conditions. This was carried out with no previous manipulation of the nymphs other than controlling their parental density. We comparatively tested the spatial distribution of newly hatched nymphs on perches located at different ranges within an emergence arena, and the expected Poisson （random） distribution. Hatchlings were found to disperse among the perches in a pattern significantly different from that expected by random. Irrespective of their parents＇ phase, the observed distributions of all nymphs were clearly clumped, similar or close to those expected for gregarious locusts. It seems that rather than emerging with a parentally derived and predetermined phase, hatchlings have an independent default or innate behavioral state, which reflects at least tolerance if not attraction to conspecifics. The typical phase behavior may later become dominant under the appropriate environmental conditions. These results imply novel perspectives on locust phase transformation, which contribute to our understanding of the formation of locust crowds under field conditions. These should be considered in any rationale for developing a preventative management strategy of locust populations.
文摘The desert locust, <em>Schistocerca gregaria</em> Forsk. (Orthoptera: Acrididae) is a peculiar insect that exhibits density-dependent phase polyphenism. Gregarious phase enables desert locust to form a large groups and mass migrations during which significant crop loss and food security issues may occur. Currently, the most recent upsurge of desert locust is prevailing across Eastern Africa and Southwestern Asia. Usually desert locusts are restricted to regions like semi-arid and arid regions. A super cyclonic storm, namely Amphan originated during May 2020, in the Bay of Bengal of North Indian Ocean has influenced numerous swarms to migrate from the Thar desert region to other parts of India. In this research, satellite data were used to investigate the reasons for this sudden swarm migration. The results that revealed the wind jets passing above the Thar desert region have integrated with the cyclogenesis of Amphan and led to the formation of conduits. The favorable conditions in the conduits include the open sky conditions, air temperature and fresh vegetation availability. Moreover, the wind settings in the conduits have enabled the swarm migrate to follow the downwind facing the sunrays during early mornings for an easy and successful take-off. It is observed that during the take-off session the wind speed at 850 hPa pressure level is mostly double than that of surface wind in both the conduits.
基金financed by the Joint Funds of the National Science Foundation of China and Yunnan Province Government(No.U1202262)the National Natural Science Foundation of China(No.30470011,31270075)+1 种基金the Local Project Y234011261(Alxa League,Inner Mongolia) and Y21C211211(Kunming,Yunnan Province)Key Laboratory of The Research Group of Systematics&Resources of Higher&Marco-Fungi,Kunming Institute of Botany,Chinese Academy of Sciences(No.0806361121)
文摘Although the species Mattiwlomyces terfezioides(≡ Terfezia terfezioides) has been recorded from China several times but it is really rare taxon with important ecological and economic value,the conspecihcity with European material has never been tested by molecular data.We re-examined three specimens labelled as T.terfezioides,one as T.leonis and one as Terfezia sp.in the herbarium HMAS and obtained five ITS and three LSU sequences.Our morphological observation and DNA sequences show that one specimen(HMAS 83766) labelled as M.terfezioides turns out to be Choiromyces sp.and the other four are M.terfezioides.The ITS and(or) LSU sequences of the Chinese samples are identical with or with 99%similarity to those from the European samples,which fully confirms the presence of M.terfezioides in China.The species is currently known from northern China(Hebei Province,Beijing and Shanxi Province).This study shows that M terfezioides has a Euroasia distribution other than European endemism and such distribution might be explained by the co-occurrence with the potential host tree Robinia pseudoacacia.
