Global Changes in Lepidopteran Phylogenetic Diversity Across Space and Time

Area of Science:

• Ecology
• Biodiversity Science
• Genomics

Background:

• Understanding insect diversity patterns is crucial due to widespread insect declines.
• Phylogenetic diversity (PD) is a key biodiversity metric linked to ecosystem processes.
• PD can be accurately estimated from opportunistic occurrence data.

Purpose of the Study:

• To assess recent global changes in Lepidopteran phylogenetic diversity (PD).
• To identify spatial and temporal patterns, regional repeatability, and environmental drivers of PD variation.
• To understand how these patterns relate to factors like latitude, region, time, and environment.

Main Methods:

• Analysis of 374,749 gene sequences from the Barcode of Life database (BOLD).
• Inclusion of 3158 species assemblages spanning 62 years.
• Assessment of spatiotemporal PD variation against null expectations considering sampling effort.

Main Results:

• Global Lepidopteran PD has significantly increased over time at high latitudes, remaining stable near the equator.
• Strongest PD increases observed in high-latitude North America and Asia, lowland Europe, and Africa.
• PD has declined in wetter areas of Australasia, Africa, and South America.

Conclusions:

• Observed PD patterns suggest responses to tropical habitat loss and poleward range expansions.
• Changes in DNA barcoding strategies may also influence observed trends.
• Genetic markers and ecological genomics synthesis are vital for detecting global biodiversity trends.