昆虫分布南界的形成原因及影响因素

生物都有一定的适生区,低温导致其分布北界的形成是不争的事实,然而一些种类还存在分布上的南界。昆虫的生长发育与环境的关系非常密切,研究其分布南界的形成原因对预测昆虫种群的扩散和暴发具有重要意义。从环境、寄主和人类活动等方面总结了北半球昆虫分布南界形成的机制及影响因素。低纬度地区夏季高温引起昆虫死亡率上升、生殖率下降、昆虫体内共生菌解体和冬季低温过高导致昆虫滞育节律被破坏等是昆虫分布南界形成的主要原因。此外,寄主的分布和人类活动也对昆虫分布南界存在一定影响。气候变暖对不同种类昆虫的分布南界影响不同,大部分昆虫的分布范围会扩大,但一些受环境限制的昆虫分布南界往往北移。建议今后对全球气候变暖背景下昆虫分布南界的变化、检疫性害虫在其原产地和入侵地分布南界的差异及其原因进行研究,以期为分析昆虫分布的变化提供依据,也为害虫防治提供新的可能途径。

Mechanisms and influential factors of southern limits in insects

Most organisms have suitable climatic and ecological geographic distribution areas. The northern limit is attributed to low temperature, but some organisms exist southern limits in their geographic ranges. Because the development of insects is tightly correlated with environment, understanding the formation causes of insects'' southern limits could provide theoretical basis for predicting their dispersal and outbreaks. In this article, the mechanisms and influential factors of insects'' southern limits in the Northern Hemisphere were summarized from environment, hosts, and human activities. In the low latitude regions, southern limits of insects could be caused by the high temperatures during summer seasons by increasing insect mortalities, decreasing insect reproduction, and disorganizing insect symbionts, as well as caused by the excessive high minimum temperatures during winter seasons by destroying insect diapause rhythm. In addition, the distribution of hosts and human activities also affect the southern limits of insects. Climate warming reveals different impacts on the southern limits of different species of insects. The distribution of most insects will be expanded, while some insects limited by environments will move northward. The changes in southern limits of insects caused by global warming, and differences in southern limits of quarantine insect pests in their native and invasive ranges, as well as the reasons, should be further studied to provide supports for predicting the changes of insect distributions, and also provide novel approaches against insect pests.