Migratory Locust Locusta Migratoria Manilensis Research Articles

Mass windborne migrations extend the range of the migratory locust in East China

Abstract Migratory insect pests pose a substantial challenge to global food security. These issues are particularly acute when pest incursions occur considerably beyond the expected range, through natural migration or human‐aided transport, because the lack of species‐specific control strategies and a potential absence of species‐specific natural enemies in the newly‐invaded area may lead to rapid establishment of a new pest. One such threat is posed by the Oriental migratory locust Locusta migratoria manilensis in China, which, historically, has been restricted to eastern China from the Bohai Gulf southwards, and now threatens to expand its range into the agriculturally important region of northeast China. We analyzed data from a recent outbreak of migratory locusts in Heilongjiang Province (extreme northeast China), > 700 km north of its current known range, and identified the source region, timing of arrival and probable migratory routes of this incursion. We further show that warming temperatures in this region will likely allow subsequent invasions to establish permanent populations in northeast China, and thus authorities in this important crop‐producing region of East Asia should be vigilant to the threat posed by this species.

BIOLOGI DAN TRANSFORMASI BELALANG KEMBARA LOCUSTA MIGRATORIA MANILENSIS MEYEN (ORTHOPTERA: ACRIDIDAE) PADA BEBERAPA TINGKAT KEPADATAN POPULASI DI LABORATORIUM

Biology and Transformation of the Migratory Locust Locusta migratoria manilensis Meyen (Orthoptera: Acrididae) at Several Laboratory Population Density Levels. The migratory locust, Locusta migratoria manilensis Meyen (Orthoptera: Acrididae) is one of insect pests in Indonesia that undergoes a unique polymorphic biology. The locust develops a transformation phase which is triggered mainly by high population density. Its recent outbreaks in several regions of Indonesia cause major concern and control strategies must be developed to strengthen control efforts in the future. Its unique polymorphic phenomenon, therefore, must be investigated thoroughly for the basis of management of the outbreak. Due to its agility and its long range flying ability, the most realistic technique to study behavioral and morphological change of the locust is in controlled condition at a laboratory or a green house facility. The experiment was aimed to study effects of colony densities on the biology and transformation process of the migratory locust. More specifically, the experiment was to study effects of population density on the feeding activity, mortality rate, and the ratio of F/C and E/F of the migratory locust L. migratoria manilensis. The population densities were simulated in colonies at 2, 5, 10, 20, dan 30 couples per cage (cage size: 45x45x90 cm) reared in a green house. Results of the experiment show that, in general, higher densities of the migratory locust colonies tended to feed more rigorously than those of the less dense colonies. The locust remained in solitary phase at the density of 2-5 couples per cage whereas the transient phase occured at the density of 10-20 couples per cage. The colonies transformed to gregarious stage when their densities were 30 couples per cage or higher. Mortality percentage tended to be higher at colonies with higher density, especially for the third instar of the migratory locust.

Use of MODIS data to monitor the oriental migratory locust plague

Outbreaks of the oriental migratory locust Locusta migratoria manilensis are a serious problem in China. This study evaluated the potential of MODIS data to monitor locust outbreaks in a heavily damaged area in Nadagang State Farm, Hebei Province. Two cloud-free MODIS images of the study area, taken before and during peak damage, were compared to determine the geographical extent and severity of the 2002 locust plague. Ground survey data were used to evaluate locust damage indicated by the normalized difference vegetation index (NDVI) derived from the MODIS data. The results showed that the NDVI reliably distinguished between before and peak damage situations for each category of damage. NDVI values were calculated pixel by pixel and changes at the same sites were compared. Areas where NDVI decreased could be clearly mapped and classified into light, moderate, and heavy damage categories according to the decrease in their NDVI value. Compared to extensive ground surveys, locust damage could be identified with 88.8% accuracy from MODIS data obtained before and during peak.

HISTORICAL EVIDENCE FOR POPULATION DYNAMICS OF TIBETAN MIGRATORY LOCUST AND THE FORECAST OF ITS OUTBREAK*

Abstract The Tibetan migratory locust (Locusta migratoria tibetensis Chen) is the highest altitude distributed subspecies among the 10 subspecies of migratory locusts. It was discovered and described as new subspecies in 1963. It is mostly distributed above an elevation of 3 000 m, with the highest up to 4 600 m, on the “Roof of the World,” viz. the Qinghai‐Xizang Plateau in southwestern China.Recent study on the historic literature revealed ancient records of locust plagues caused by Locusta migratoria tibetensis Chen in many regions of Xizang (Tibet). These disasters took place during 124 years stretching from 1828 to 1952. Forty‐five places were infested by locust swarms, and from 1846 to 1857 locust disasters occurred sucessively in 12 years, and affected 18 places of Xizang. At the severe disaster regions crops were damaged by locusts in such a degree that there was no harvest at all. At the same time, locust plagues due to another subspecies also occurred in the plains between the Yellow River and Huaihe and Haihe Rivers in East China.The disasters in Xizang were caused by the Tibetan migratory locust, while in Huang‐Huai‐Hai Plain disasters were due to the Oriental migratory locust Locusta migratoria manilensis (Meyen). This study not only provides the evidence that the Tibetan migratory locust has been existing as a separate subspecies with a long history, but also reveals the relevant years of locust plagues, their regional distribution and intermittent rules of locust plagues. It also offers a scientific basis for forecasting Tibetan migratory locust disasters and related monitoring strategies; as well as understanding the close relationship between the outbreak of the migratory locust and drought.