Diversity study of acridian fauna in Senegal

Acridians are among the most destructive insects to agriculture worldwide. In many tropical regions, only a few of the approximately 10,000 locust species represent a major threat to agriculture. In Senegal, crops and even trees are regularly attacked by crickets and grasshoppers. The exact number of locusts remains unclear but is generally estimated to be in the Sahel. The aim of this study is to determine the locust fauna in Senegal focusing on six administrative regions covering a total area of 62,473 square kilometers. Over six years, from 2019 to 2024, we carried out net captures and light trapping during both the dry and rainy seasons. We carried out 1,800 captures per region, totaling 10,800 samples for the whole country. The captured individuals were identified using classification and identification keys. The 270,000 individuals captured belong to 156 species, 14 subfamilies and 3 families. Some species are observed year-round, although females enter imaginal diapause, while others are found only during the rainy season and remain in embryonic diapause during the dry season. Our study showed that species previously described are no longer present in Senegal and have consequently decreased their range. To the best of our knowledge, this study is the first of its type in Senegal. Previous surveys of locust fauna have been conducted in the broader context of the Sahel, rather than specifically in Senegal.