New distribution records of Aedes aegypti (Linnaeus), Aedes mediovittatus (Coquillett), and Toxorhynchites portoricensis (Röder) (Diptera: Culicidae) in Puerto Rico and their relevance to integrated vector management

As of October 2025, Puerto Rico has been experiencing an ongoing dengue outbreak that started in March 2024. The latest island-wide mosquito survey conducted in Puerto Rico during 2018 to 2019 covered 41 of the 78 municipalities and detected the presence of Aedes aegypti (Linnaeus, 1762) in 27 of the municipalities. Given the prolonged elevated circulation of the dengue virus on the island, we carried out an Ae. aegypti survey in June 2025 across 48 out of 78 municipalities. Here, we report the occurrence of Ae. aegypti in 43 out of 48 municipalities surveyed, some of which have not been reported in previous studies. Notably, 77.6% of cemeteries surveyed across 24 municipalities served as oviposition sites for Ae. aegypti and were found in 10 municipalities not previously recorded in literature. Due to observed frequency of shared larval habitat with Ae. mediovittatus (Coquillett, 1906), an analysis of co-occurrence patterns is provided from collected sites. In addition, updated distribution of Ae. mediovittatus is provided. The larvivorous Tx. portoricensis (Röder, 1885) was observed opportunistically, and co-occurrence analysis was performed to assess its potential for biocontrol. We also documented effective integrated pest management practices that minimize mosquito breeding where mosquito larvae were absent. Overall, the updated distribution of the three species in Puerto Rico reveals a broader distribution than previously reported, and co-occurrence analysis confirms that Ae. aegypti and Ae. mediovittatus frequently share larval habitat. This highlights the implications for dengue transmission risk and the need for continuous surveillance to support mosquito control efforts.