On November 7, 2023, 3 female specimens of Aedeomyia squamipennis were captured in Collier County, Florida, for the first time during routine adult mosquito surveillance in Collier Seminole State Park. This species was first found in the USA in Miami-Dade County in 2016 and has since expanded into multiple counties throughout South Florida. The presence of Ad. squamipennis has implications for arbovirus transmission as it is a vector for the Venezuelan equine encephalitis virus group. The detection of this mosquito species also highlights the importance of a robust and consistent mosquito surveillance program.

Aedeomyia squamipennis (Lynch Arribálzaga) is 1 of 7 species of mosquito belonging to the genus Aedeomyia (Theobald) and is endemic to the tropics of Central and South America. Primarily feeding on avian hosts in the forest canopy, Ad. squamipennis is suspected in the transmission of Venezuelan equine encephalitis virus (VEEV) (Calisher et al. 1981), and an important vector of the Gamboa virus group (Dutary et al. 1989) and avian malaria (Loaiza and Miller 2013). The larval stage of Ad. squamipennis uses aquatic plants such as water lettuce (Pista stratiotes L.) for respiration and shelter during larval development, similar to mosquitoes of the genus Mansonia (Blanchard).

In October 2016, Ad. squamipennis was detected for the first time in the United States in Florida City, Florida, in Miami-Dade County (Burkett-Cadena et al. 2017). It has since been detected in Monroe and Palm Beach counties in 2021 (Boehmler 2022, Fazekas et al. 2023). This trend of expansion suggests that the tropical climate of South Florida is suitable for Ad. squamipennis habitation, though it remains to be seen if long-term establishment is possible for the species. Until recently, Ad. squamipennis had not yet been detected in Collier County, Florida. Here we report the identification of 5 total specimens of Ad. squamipennis collected from traps placed in Collier Seminole State Park and Picayune Strand State Park. The addition of this mosquito species to Collier Mosquito Control Districts’ (CMCD) observed species list brings the total number of mosquito species known in Collier County to 52, highlighting the pertinence of continued and thorough surveillance.

As part of routine weekly adult mosquito trap surveillance, a Centers for Disease Control and Prevention (CDC) miniature light trap (John W. Hock Company, Gainesville, FL, USA) with a 0.95 watt incandescent light and baited with carbon dioxide using a compressed tank was placed on the Prairie Hammock Trail in Collier Seminole State Park (25.99707, –81.59960) (Fig. 1). After 24 h, the trap was collected and brought to CMCD’s laboratory for species identification. The trap collections from November 7, 2023 contained Culex nigripalpus Theobald (51), Culex of the subgenus Melanoconion Theobald (17), Culex coronator Dyar and Knab (7), Mansonia dyari (Belkin, Heinemann and Page) (6), Mansonia titillans (Walker) (4), Aedes taeniorhynchus (Wiedemann) (3), Culex quinquefasciatus Say (3), and Uranotaenia lowii Theobald (3). In addition, multiple specimens of Ad. squamipennis (3) were separated for further review due to their unique morphology. The Ad. squamipennis specimens were initially identified using morphological characteristics described in Burkett-Cadena et al. (2017). Distinguishing features of this mosquito include the presence of broad wing scales, the apical tuft of scales on the mid-femora and the short, thick multicolored scaled flagellomeres (Fig. 2A).

Fig. 1.

Map of southern Collier County with public lands highlighted in green and blue markings indicating localities where Aedeomyia squamipennis has been collected between November 2023 and March 2024. Insert at the top right shows location in Florida of the enlarged map.

Fig. 1.

Map of southern Collier County with public lands highlighted in green and blue markings indicating localities where Aedeomyia squamipennis has been collected between November 2023 and March 2024. Insert at the top right shows location in Florida of the enlarged map.

Close modal
Fig. 2.

(A) Image of the original Aedeomyia squamipennis collected in Collier County FL, depicting the morphological characters used for identification. Note the apical scale tufts on the mid-femora, and the short, thick antennal flagellomeres. (B) Neighbor-joining tree of all available Aedeomyia species inferred with IQ-TREE based on the DNA barcoding region of the COI gene, rooted to Uranotaenia anhydro Dyar. Accession numbers are present on labels for sequences mined from BOLD. Scale bar represents expected number of nucleotide substitutions per site. Red dot denotes Ad. squamipennis collected in Collier County, Florida. BOLD, Barcode of Life Datasystems.

Fig. 2.

(A) Image of the original Aedeomyia squamipennis collected in Collier County FL, depicting the morphological characters used for identification. Note the apical scale tufts on the mid-femora, and the short, thick antennal flagellomeres. (B) Neighbor-joining tree of all available Aedeomyia species inferred with IQ-TREE based on the DNA barcoding region of the COI gene, rooted to Uranotaenia anhydro Dyar. Accession numbers are present on labels for sequences mined from BOLD. Scale bar represents expected number of nucleotide substitutions per site. Red dot denotes Ad. squamipennis collected in Collier County, Florida. BOLD, Barcode of Life Datasystems.

Close modal

On February 13, 2024, an additional specimen of Ad. squamipennis was identified while sorting through the same CDC light trap from Collier-Seminole State Park (Fig. 1). The trap location remained static from the last detection of Ad. squamipennis in November 2023, implying that the mosquito has established itself in the area. Trap contents for this date also included Ae. taeniorhynchus (9), Ma. titillans (8), Cx. nigripalpus (5), An. crucians (8), and Aedes infirmatus Dyar and Knab (8). Additionally, on March 26, 2024, another specimen of Ad. squamipennis was found in routine surveillance using a CDC light trap at the Sabal Palm Hiking Trailhead in Picayune Strand State Forest (26.09530, –81.63401). Mosquito species found alongside Ad. squamipennis included: An. crucians (133), Cx. erraticus Dyar and Knab (55), Cx. nigripalpus (142), Cx, cedecei Stone and Hair (22), and Ma. dyari (8).

Initial identification of the November 2023 specimens were confirmed using DNA barcoding analysis of the cytochrome c oxidase subunit I (COI) gene as previously described (Herbert er al. 2003, Fazekas et al. 2023). Specimens were sent to UF-IFAS-FMEL, and processed using molecular procedures as described by Reeves et al. (2023). In short, a single leg was removed from the specimen and used for DNA extraction. A fragment of the COI gene was amplified by polymerase change reaction (PCR), and COI amplicons were sequenced by Eurofins Genomics (Louisville, KY, USA) using traditional Sanger sequencing (Sanger et al. 1977). The resulting sequences were edited for quality using Geneious Prime Version 11.0.6 (Biomatters, Auckland, New Zealand), then submitted to the Barcode of Life Data System (BOLD) v. 4 Identification Engine for reference sequence comparison (Ratnasingham and Herbert 2007). Collier Ad. squamipennis COI sequences were compared to all Aedeomyia species in the BOLD database and to Ad. squamipennis sequences collected from Miami-Dade and Palm Beach Counties using IQ-TREE version 2.2 (Nguyen et al. 2015). Collier Ad. squamipennis groups with Miami-Dade and Palm Beach County specimens, with sequences similar to Ad. squamipennis specimens collected in Colombia (Fig. 2B).

The unique morphology and scaling of Ad. squamipennis described above is useful for accurate identification as it continues to expand into new environments throughout Florida. Because it has expanded its range to multiple counties in southern Florida since its initial detection in 2016, it could be said that Ad. squamipennis may continue to migrate in a northern direction. Therefore, mosquito control programs need to remain vigilant and use up-to-date identification keys.

The continued range expansion of Ad. squamipennis is a trend that has been observed in South Florida since 2016 (Burkett-Cadena et al. 2017). The majority of the detections for this species are along eastern edge of the Florida Everglades (Fazekas et al. 2023), detections in Collier Seminole State Park and Picayune Stand State Forest indicate that Ad. squamipennis has further expanded its range into the Western Florida Everglades. Although this mosquito species is not found in high enough numbers to cause any immediate concern, it is worth noting that if this expansion continues northward, there is a potential risk of introducing arboviruses into communities adjacent to its habitat.

Aedeomyia squamipennis is just 1 of 9 new species records for Collier County since 2019 (Riles and Connelly 2020, Tyler-Julian et al. 2022, Heinig et al. 2023a, 2023b; Reeves et al. 2023). Much of the environment across Collier County is high in biodiversity, likely explaining the introduction of Ad. squamipennis and others to the area. Collier Seminole State Park and Picayune Stand State Forest in particular is host to a variety of plant and animal species, many of which support the proliferation of several species of mosquito. The identification of Mansonia species alongside Ad. squamipennis in traps suggests the presence of suitable habitat, particularly water lettuce, in these areas.

Collier Seminole State Park has been a prominent site for new species records, having been one of the first locations that Ae. scapularis (Rondani) (Heinig et al. 2023a), Ae. tortilis (Theobald) (Heinig et al. 2023b), and Cx. declarator Dyar and Knab (Heinig et al. 2023b) were identified. Preservation areas, like state parks and state forests, play a crucial role in safeguarding fragile ecosystems and boosting biodiversity, and as such, these protected lands typically experience little to no mosquito management or aquatic weed control efforts. This situation fosters environments conducive to the proliferation of unique, sometimes invasive, vectors and arboviruses, which might struggle to find a foothold in areas with more extensive development. Detecting another invasive species during routine surveillance in Collier Seminole State Park and Picayune Strand State Forest highlights the importance of collaboration between mosquito control programs and public land managers, especially in relation to routine mosquito and arbovirus surveillance.

Although Ad. squamipennis is not currently prevalent in Florida, aquatic weeds found throughout much of Florida are likely to provide a suitable habitat for populations of the mosquito as it expands (Adams and Lee 2007). The presence of water lettuce and other aquatic plants in protected habitats (Wilder and Thomas 2016) may also be a factor in the expansion of Ad. squamipennis. Additional research and surveillance into the distribution of Ad. squamipennis in south Florida and its progress northward is required to assess risk of disease transmission by this vector. Further, with extensive water lettuce throughout Collier County, it is likely that Ad. squamipennis will expand to more northern preservation and agricultural areas of the county, as indicated by detection in Picayune Stand State Forest. Because of this it is likely that Ad. squamipennis will establish itself throughout the county, positioning water lettuce as not only a producer of nuisance mosquito species but now also as a potential public health threat.

The authors thank the Collier Mosquito Control District (CMCD) Board of Commissioners and Executive Director Patrick Linn. We also thank all the employees at CMCD who participated in sample collection and technical assistance. This work was performed under a Scientific Research Colleting Permit (Permit Number 04012424) issued by the Florida Parks Service, Florida Department of Environmental Protection, and an Arthropod Management Plan–Public Lands with the Florida Forest Service, Florida Department of Agriculture and Consumer Services.

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