Spatial Distribution and Morphological Characteristics of the Cochineal Insect (Dactylopius opuntiae) in Northwestern Libya: Az-Zawiya City as a Model

Abstract

The invasive cochineal insect, Dactylopius opuntiae (Cockerell), poses a catastrophic biological threat to prickly pear (Opuntia ficus-indica) plantations in North Africa. This study investigates the spatial distribution and morphological characteristics of D. opuntiae in Az-Zawiya city, northwestern Libya, as a representative model for the region. Field surveys were conducted across nine farms categorized into three geographical sectors: Coastal, Central, and Inland. Morphological analysis using stereomicroscopy confirmed the species identity, showing robust adaptive traits such as dense protective wax and high carmine dye content. Spatial mapping revealed a significant latitudinal gradient, with infestation severity peaking in the Inland sector (Mean Grade 3.9 ± 0.1) compared to the Coastal sector (Mean Grade 1.5 ± 0.3). Multiple linear regression analysis demonstrated that temperature and distance from the coast are the primary environmental drivers, explaining 85.3% of the variation in infestation levels (R² = 0.853, P < 0.001). The impact on host plants was severe in inland hotspots, with 25% total plant mortality and 60% cladode abscission. These findings underscore the urgent need for prioritized biorational control strategies and the establishment of a GIS-based early warning system to prevent the total collapse of the cactus-based ecosystem in northwestern Libya.