Fig 1.
Map of the sites where Ae. aegypti were collected.
For detailed populations information refer to Table 1.
Table 1.
Details of the populations studied.
Table 2.
Definitions of the variables used to test the hypothesis that human transportation influences population structure of Ae. aegypti in the central-western Philippines.
Table 3.
Fixation indexes (Fst) calculated for each pair of populations studied.
Table 4.
Results of regression models.
Fig 2.
Three-dimensional scatter plot with regression plane that visualizes the effect of the variables called “Density” and “Cargo” on pairwise Fst values.
Both predictors are negatively correlated to Fst and the relative regression coefficients are very low in absolute value. This means that a remarkable increase in Cargo and Density is necessary to cause a unit decrease in Fst values. The interpretation is that where cargo shipments are intense and human population is dense Ae. aegypti are more genetically similar. This suggests an influence of human transportation on mosquitos’ migration. Refer to Table 2 for detailed description of the variables.
Fig 3.
Principal component analysis used to summarize seven variables related to port size and connectivity; plot of the first two PCs.
Red arrows represent the vectors of the seven variables and each point in the plot is a port (Fig 1 and Table 1). The direction of principal component 1 (PC1) is almost opposite to the variables and it explains 74% of the total variance in the dataset; therefore, ports with low values of PC1 were considered big and highly connected (and vice versa). Refer to Table 2 for a detailed description of each variable.
Fig 4.
Each individual is represented by a vertical bar whose colors show the probability to be assigned to specific clusters. Populations are separated by vertical black lines and identified by the numbers at the bottom (Fig 1 and Table 1). K = number of genetic clusters. Overall, a low level of genetic structure was detected. At K6 and K9 most populations from busy ports show genetic admixture, while most populations from idle ports are genetically clustered (compare with Fig 3).