Detecting flying insects using car nets and DNA metabarcoding

Area of Science:

• Ecology
• Entomology
• Molecular Ecology

Background:

• Monitoring insect diversity across large spatial scales is challenging due to taxonomic and functional diversity.
• Traditional methods are often time-consuming and spatially limited.

Purpose of the Study:

• To evaluate the efficacy of car-mounted nets combined with DNA metabarcoding for large-scale flying insect sampling.
• To assess insect richness and diversity across different biogeographic regions and land cover types in Denmark.

Main Methods:

• Collecting 365 bulk insect samples using car nets across 218 routes in Denmark during June 2018.
• Utilizing DNA metabarcoding to determine taxonomic composition from collected samples.
• Comparing metabarcoding results with existing Danish insect occurrence data.

Main Results:

• Detected 15 out of 19 flying insect orders, with a notable proportion of Diptera.
• Observed lower insect richness and diversity in urbanized areas compared to other land cover types.
• Identified 319 species previously unknown in Denmark and 174 species listed on the Danish Red List.

Conclusions:

• Car nets and DNA metabarcoding provide a scalable method for assessing flying insect fauna over large areas.
• The methodology offers valuable insights into biodiversity, including the discovery of new species and threatened taxa.
• Potential biases towards certain insect orders, common to many sampling methods, should be considered.