Maturation of field-collected female Agriotes obscurus and Agriotes lineatus (Coleoptera: Elateridae) over their swarming period.

This article focuses on the maturation and egg development of female click beetles, Agriotes obscurus and Agriotes lineatus, which are significant pests of vegetable and field crops in Europe and North America. Through dissection of over 2,900 female beetles collected in southwestern British Columbia from 2015 to 2020, the study identifies six consecutive maturity stages based on abdominal lipid content and egg development during the beetles’ spring swarming period. Findings indicate that beetles emerge with high lipid reserves and no eggs, then develop immature and mature eggs as lipid content decreases, with active ovarioles present throughout the swarming season, suggesting egg production may continue until the end of the season and depend on both stored lipids and adult diet. These results have implications for wireworm pest management, highlighting the need for repeated or combined control tactics targeting beetles before oviposition due to the prolonged and variable egg-laying period.