Historical invasion rates vary among insect trophic groups

Area of Science:

• Ecology
• Invasive Species Biology
• Conservation Biology

Background:

• Globalization facilitates the spread of invasive insect species, leading to significant ecosystem service losses.
• Previous research suggests plant invasions create niches that favor non-native herbivorous insects.
• A comprehensive understanding of invasion success across different insect feeding groups is lacking.

Purpose of the Study:

• To compare the proportions of insect trophic groups among non-native species versus the world's fauna.
• To analyze changes in invasion success for each trophic group over the past three centuries.
• To investigate the temporal relationship between plant, herbivore, and parasite invasions.

Main Methods:

• Compiled data on larval trophic groups for 5,839 non-native insect species across nine global regions.
• Compared the proportional representation of insect feeding guilds in non-native fauna versus global fauna.
• Analyzed historical invasion trends and cross-correlations between plant and insect invasions.

Main Results:

• Herbivores constitute a significantly larger proportion (52.4%) of non-native insects compared to global fauna (38.4%).
• Proportions of non-native detritivores, predators, and brood-carers are significantly lower; parasite proportions are similar.
• Herbivore invasions lag plant invasions by approximately 80 years, while parasitoids co-invade with hosts.

Conclusions:

• Herbivores are the dominant feeding group among invasive insects, strongly linked to plant invasions.
• Plant invasions appear to be a primary driver of the increasing number of non-native insects globally.
• Understanding trophic group dynamics is crucial for predicting and managing insect invasions.