Table 1.
Mosquito specimens used in this study.
Fig 1.
Bayesian inference of a phylogenetic tree based on the nucleotide sequences of the mitochondrial COI region (1542 bp) of 69 Cx. tritaeniorhynchus specimens.
A: Summarized Bayesian phylogenetic tree with 86 COI sequences of Cx. vishnui subgroup and 23 sequences as an outgroup. The black frame indicates Cx. vishnui subgroup, and the dotted frame indicates Cx. tritaeniorhynchus. B: Expanded subtree of 86 COI sequences of Cx. vishnui subgroup. Bootstrap values correspond to 1000 replications. Bar denotes the nucleotide similarity distance. GenBank accession numbers for sequences used in the phylogenetic analysis are in S1 Table. Open and closed triangles with blue indicate Ct-J and Ct-C subtypes of the Cx. tritaeniorhynchus specimens, respectively, captured in net-traps (NTs) and a Johnson-Taylor suction trap (JT-ST).
Fig 2.
Bayesian inference of a phylogenetic tree based on the partial nucleotide sequences of the mitochondrial COI region (658 bp) of 69 Cx. tritaeniorhynchus specimens.
A: Summarized Bayesian phylogenetic tree with 86 COI sequences of Cx. vishnui subgroup and 23 sequences as an outgroup. The black frame indicates Cx. vishnui subgroup, and the dotted frame indicates Cx. tritaeniorhynchus. B: Expanded subtree of 86 COI sequences of Cx. vishnui subgroup. Numbers at nodes indicate posterior probability values (>0.7) based on 150,000 trees: two replicate Markov chain Monte Carlo runs, consisting of six chains of 10 million generations each sampled every 100 generations with a burn-in of 25,000 (25%). Bar denotes the nucleotide similarity distance. GenBank accession numbers for sequences used in the phylogenetic analysis are in S1 Table. Open and closed triangles with blue indicate Ct-J and Ct-C of the Cx. tritaeniorhynchus, respectively, captured in net-traps (NTs) and a Johnson-Taylor suction trap (JT-ST).
Fig 3.
Locations of the mosquito collection sites in this study are shown here and details are given in S1 Table.
The phylogenetic analysis indicated the Cx. tritaeniorhynchus was categorized into two taxa, Ct-J (open circles) and Ct-C (closed circles). The Cx. tritaeniorhynchus were captured in net-traps (NTs) and a Johnson-Taylor suction trap (JT-ST) installed at four localities on the Kyushu District (shaded area). Open and closed triangles with blue indicate capture of Ct-J and Ct-C of the Cx. tritaeniorhynchus, respectively. Double circles indicate specimens not used in the phylogenetic analysis, but are plotted on the map as the Ct-C referred from the COI sequences of the GenBank database. A map was created using free materials downloaded from the following websites: https://power-point-design.com/ppt-design/world-map-for-powerpoint/ and https://power-point-design.com/ppt-design/japan-map-available-for-powerpoint/. Based on the geographical positions recorded using a geographical positioning system (GPS: GPSMAP64, Garmin, USA) (S1 Table), the collection sites were plotted on this map.
Table 2.
Mosquitoes captured in net traps and a Johnson-Taylor suction trap in 2009 and 2010.
Fig 4.
The days of Cx. tritaeniorhynchus capture in net-traps (NTs) and a Johnson-Taylor suction trap (JT-ST) installed at four localities on the Kyushu District.
A: Saga City in 2009, B: Minami-Satsuma City in 2009, C: Goto City in 2010, D: Iki City in 2010. Open and solid bars indicate Ct-J and Ct-C subtypes of the Cx. tritaeniorhynchus, respectively, which were determined by the partial COI sequences (658 bp).
Fig 5.
Comparison of a total flight time between Cx. tritaeniorhynchus (Ct-J, shaded bars) and Cx. p. pallens (Cpp, open bars) under each flight condition.
The bars represent the mean with standard deviations (SDs). An independent two sample t-test assuming unequal variances was applied to determine significant differences. Statistically significant differences are indicated shown by Roman numerals; a, p < 0.001; b, p < 0.01; c, p < 0.1.
Fig 6.
The frequencies of rotations within 5 s in the flight mill experiments between Cx. tritaeniorhynchus (Ct-J, closed circles) and Cx. p. pallens (Cpp, open circles).
A: Cpp at 15°C, B: Ct-J at 15°C, C: Cpp at 20°C, D: Ct-C at 20°C, E: Ct-J* (Ct-J females were reared at 25°C, but flight experiments were conducted at 20°C) at 20°C, F: Cpp at 25°C, Ct-C at 25°C. Bold lines indicate the longest total flight time in each condition of Cpp at 15°C (A) and Ct-J* at 20°C (E).
Fig 7.
Comparison of the flight pattern between Cx. p. pallens (Cpp) at 15°C (A) and Cx. tritaeniorhynchus (Ct-J*) at 20°C (B).
A and B are the flight patterns of the individuals with the longest total flight time in each experiment of Fig 6A and 6E, respectively. Flight patterns of Cpp and Ct-J* were observed for 69 h and 72 h, respectively. The shaded area marks environmental darkness.
Fig 8.
Computed back trajectories at 2-h intervals for the 36-h period ending at 1500 UTC of 8 and 10 July 2009 at Saga City (A and B), and 30 June 2010 at Goto City (C).
Top portion shows the horizontal path, and the bottom portion shows the vertical path of the trajectories. Each figure is the result of a backward trajectory analysis of HYSPLIT using the NOAA website: https://www.ready.noaa.gov/HYSPLIT.php.