Summary :To investigate whether different landscapes could affect genetic diversity and structure of the cosmopolitan diptera Stomoxys calcitrans, populations from Gabon and southern France were studied using dominant amplified fragment length polymorphism (AFLP) markers. Gabon is characterized by a forested closed landscape, and southern France by an open Mediterranean landscape. The genetic diversity between Gabon and France populations did not differ significantly (P > 0.05). Contrary to our expectation, this study shows a moderate level of genetic differentiation between these two distant countries (Fst = 0.0979) and a low genetic structure among Gabonese and French populations (Fst = 0.0291 and 0.0275 respectively). This result could indicate the capacities of S. calcitrans populations to sustain a high level of gene flow, despite geographic distance and isolation. T he relationship between landscape pattern and population structure has become a major interest of many population genetics studies. Manel et al. (2003) coined the term of landscape genetics to describe combination of landscape ecology and population genetics. Thus, the landscape genetics approach provides information about the interaction between landscape features and microevolutionary processes such as gene flow, genetic drift and selection (Manel et al., 2003;Storfer et al., 2007). Although the common thought is that environmental and ecological changes exacerbate the risk of decline or extinction of species, it is also important to consider organisms that may be favoured by current environmental changes. Particularly, insects that have an immense ecological capability of adaptation and a great biological success in diverse environments (Behura, 2006;Mock et al., 2007). A number of recent studies highlighted the effects of landscape characteristics on patterns of genetic population structuring, including in insects (Keyghobadi et al., 1999;Hunter, 2002). Our team is presently working on stable fly populations. Stable fly, Stomoxys calcitrans (L) (Diptera, Muscidae), is a cosmopolitan insect that usually lives in close association with large domestic mammals and human beings (Zumpt, 1973). Both sexes are hematophagous. Their economic impact has been well established (Campbell et al., 1987). These flies cause important economic losses in the cattle breeding, by their direct pathogenic effects (blood predation, irritation of the animals, reduction in immunizing defences, reduction in the production of milk...) and by their role in the transmission of certain pathogenic agents (Campbell et al., 2001;D'Amico et al., 1996). S. calcitrans historically has been a pest of livestock in confined operations but seldom of animals on pastures (Broce et al., 2005). These flies are found essentially in rural areas near stables, slaughter houses, cattle markets and the rubbish dumps, locations related mainly to the presence of fermenting organic material (Batista et al., 2005;Eesa & El-Sibae, 1993). Describing insect diversity and ecology is important to und...