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Flying to new horizons: What secrets are revealed in the mysterious migration journey of brown migratory locusts?
Brown migratory locust (Nilaparvata lugens), an insect that uses rice as its host, is becoming one of the most threatening rice pests in the world. This small insect not only directly affects the growth of rice, but can also transmit two viruses, causing crop yields to decrease by up to 60%. With the impact of climate change and agricultural activities, the migration patterns and ecological behavior of brown migratory locusts have received increasing attention.
Biological characteristics
The shape of brown migratory locusts can be divided into two categories, namely the "long-winged type" with complete wings and the "short-winged type" with truncated wings. These two forms of insects play different roles in the ecosystem. Both females and males of the long-winged form are potential migrants, responsible for colonizing new habitats, while the short-winged form usually occupies a fixed area of rice fields when breeding.
"Brown migratory locust populations in East Asia migrate in a closed circuit, while populations in the Malay Archipelago and South Asia mainly migrate in one direction to Indochina."
Damage caused
The damage caused by brown migratory locusts to rice mainly occurs at various growth stages of the plant. Feeding by larvae and adults causes the rice to quickly turn yellow and wither. Early-stage affected rice fields often see round yellow patches that later turn brown, a phenomenon known as "locust burn." Research shows that temperature is an important factor affecting the daily routine of these insects. The hatching rate and survival rate of eggs are the highest at about 25°C.
Natural enemies and ecological balance
The brown migratory locust's natural enemies, including small spiders such as Pardosa pseudoannulata and Araneus inustus, play a role in limiting its numbers in nature. However, in agricultural production, the use of some pesticides may have a negative impact on natural enemies, causing the number of brown migratory locusts to increase again.
"Some pesticides will increase the protein content of the male accessory glands of brown migratory locusts, thereby improving their reproductive capacity."
Management and control strategy
Faced with the threat of brown migratory locusts, integrated pest management (IPM) strategies are particularly important. Excessive use of nitrogen fertilizers and pesticides can lead to the breeding of migratory locusts, so limiting inappropriate use of pesticides is the key to control. In 2011, the Thai government announced initiatives to limit the use of pesticides linked to the spread of brown migratory locusts, with support from the International Rice Research Institute (IRRI).
"Resistance in rice varieties, such as IR64, is critical in preventing brown migratory locust outbreaks."
The impact of climate change on brown migratory locusts
Research shows that brown migratory locust larvae are living within the upper temperature range for their survival. As the global climate warms, especially extreme high temperatures in tropical areas, there may be further restrictions on the survival and distribution of brown migratory locusts.
Future Outlook
Faced with the increasingly severe threat of brown migratory locusts, the scientific community continues to research new control technologies, trying to achieve more effective brown migratory locust control through genetic technology and biological control methods. At the same time, adjustments to agricultural policies will also be an important direction in preventing harm in the future.
"In the process of dealing with brown migratory locusts, we must not only protect crops, but also think about how to maintain the balance of the overall ecosystem."
In such a complex ecological environment, the behavior of brown migratory locusts not only brings challenges to agriculture, but also makes us think about the subtle relationship between human activities and the natural world?
