Intraspecific Variation and Host Range of Aclypea opaca (Coleoptera: Silphidae) Damaging Root Vegetables in Temperate Regions

Abstract

Aclypea opaca (Coleoptera: Silphidae) is an important pest of root vegetable crops in temperate agricultural regions, where both larvae and adults contribute to significant economic losses through feeding damage to underground plant tissues. The pest attacks a range of cultivated root vegetables, causing root scarring, tissue decay, reduced market quality, and lower crop yield. Understanding the intraspecific variation and host range of A. opaca is essential for predicting pest outbreaks and developing effective management strategies. The present study was conducted to investigate the morphological and biological variation among A. opaca populations and to evaluate their host range across economically important root vegetable crops. Field surveys and laboratory experiments were carried out using populations collected from different temperate production regions. Morphological measurements, developmental characteristics, feeding behavior, and reproductive performance were assessed to determine variation among populations. Host preference and suitability experiments were conducted on several root vegetable crops to evaluate larval survival, feeding intensity, and population development. The results revealed considerable intraspecific variation among A. opaca populations in terms of body size, developmental duration, feeding activity, and reproductive capacity. Differences in adaptation to environmental conditions and host utilization were also observed among geographic populations. Host range experiments demonstrated that the pest was capable of successfully colonizing and developing on multiple root vegetable crops, although certain hosts were more favorable for growth and reproduction. Crops with softer root tissues and higher nutrient content supported greater feeding damage and faster population development. The findings indicate that A. opaca possesses broad ecological adaptability and the ability to exploit diverse host plants in temperate agroecosystems. This study provides important insights into the biology, host utilization, and population variability of A. opaca, which are essential for improving pest monitoring and designing integrated pest management strategies aimed at minimizing damage in root vegetable production systems.