Historical plant introductions predict current insect invasions.

Area of Science:

• Ecology
• Invasive Species Biology
• Conservation Science

Background:

• Thousands of insect species are invasive globally, impacting ecosystems and human societies.
• Nonnative plants provide essential resources and habitats, facilitating insect establishment and acting as introduction pathways.

Purpose of the Study:

• To test the hypothesis that plant invasions precede and promote insect invasions.
• To quantify the current and future impact of nonnative plants on insect invasions.

Main Methods:

• Analysis of geographical variation in nonnative insect and plant flows.
• Statistical modeling to assess the predictive power of past plant flows on current insect invasions.
• Estimation of global insect invasion debt based on observed time lags.

Main Results:

• Nonnative plant flows dating back to 1900 were the strongest predictor of current nonnative insect flows.
• Nonnative plant flows outperformed socioeconomic variables in predicting insect invasions.
• An estimated 3,442 region-level insect introductions (invasion debt) were identified, potentially increasing global insect invasions by 35%.

Conclusions:

• Plant invasions significantly precede and facilitate insect invasions.
• The Afrotropics, Neotropics, and Indomalaya face the largest future increases in nonnative insect discoveries.
• Controlling nonnative plant spread is a critical strategy for mitigating future plant and insect invasions.