Ecological patterns of Lissachatina fulica in a seasonally dry biome: implications for control

Abstract The giant African snail (Lissachatina fulica), one of the world’s most harmful invasive species, has spread across all Brazilian states. However, population-level studies in some biomes, like the Cerrado, remain scarce. This study provides the first comprehensive assessment of the distribution, density, shell morphometry, and reproductive characteristics of L. fulica in the Brazilian Federal District. Between 2021 and 2022, 25 field expeditions were conducted, resulting in the capture of 5,242 individuals. The species was predominantly found in moderately disturbed urban areas with vegetation and organic debris, while it was absent from highly urbanized zones, possibly due to climatic limitations or lack of suitable microhabitats. Population densities were generally low (<0.33 ind/m2), with nearly half of the individuals concentrated at three sites. Shell length ranged from 13 to 163 mm, showing a bimodal distribution. Morphometric analysis indicated negative allometry and earlier elongation compared to other regions, possibly reflecting earlier onset of reproductive maturity. Gravid individuals, mostly 50–103 mm long, were recorded in 80% of the sites. The reproductive cycle appears to be strongly influenced by seasonality, with over 85% of annual rainfall occurring from November to April, which coincides with post-estivation activity and egg-laying. The maximum number of eggs per individual (246) was lower than in other studies, likely due to a shorter reproductive window. These findings suggest that targeted control strategies in the Federal District are still feasible and should prioritize early rainy-season collection in moderately urbanized areas, focusing on individuals exceeding 50 mm in shell length.