Title : Assessment of insect biodiversity in industrial hemp crops
Abstract:
Industrial hemp (Cannabis sativa L.) has increasingly been recognized as a sustainable agricultural crop, with low environmental impact and high potential to promote biodiversity in agricultural systems. Although its pollination is anemophilous and therefore independent of insect pollinators (Lipson Feder et al., 2021), hemp produces large quantities of pollen (O'Brien & Arathi, 2019), making it a relevant food resource for beneficial insects, particularly during periods of scarcity of entomophilous flowering plants (Saunders, 2018). The recurrent presence of bees on hemp inflorescences suggests that this crop may play a complementary role in maintaining pollinator diversity and abundance in intensive agricultural landscapes (González-Varo et al., 2013; Potts et al., 2010).
In this context, the present study was developed within the BGREENER project, in the cross-border EUROACE region (Central Portugal, Extremadura, and Alentejo), with the aim of assessing the contribution of industrial hemp to entomological biodiversity. The trial was conducted over two growing seasons (2024 and 2025), with four industrial hemp varieties established (Futura 75, Fibror 79, Santhica 27, and Mona 16). Biodiversity assessment was based on insect sampling using entomological aspiration in two contrasting areas: a hemp crop plot and a fallow plot with spontaneous vegetation. Sampling followed a zig-zag pattern to ensure spatial representativeness. Insect identification was carried out using the Rapid Biodiversity Assessment (RBA) methodology, allowing functional and taxonomic classification of captured individuals. Results showed higher insect abundance and richness in the hemp plot compared to the fallow area. In 2024, 365 insects were captured in the hemp plot and 126 in the fallow plot; in 2025, captures increased to 482 and decreased to 63 insects, respectively. Hemiptera and Coleoptera were the most abundant orders in both years, with phytophagous insects predominating. Nevertheless, a consistent presence of effective pollinators was recorded, namely from the families Apidae, Andrenidae, and Vespidae.
The results demonstrate that industrial hemp acts as a temporary ecological hotspot, contributing to increased functional biodiversity in agricultural environments. Therefore, this crop has the potential to be integrated as an ecological infrastructure in sustainable farming systems, although its implementation should be assessed on a case-by-case basis, considering landscape context and adjacent crops.
