Mosquito Sampling
The wing dataset is composed of images consolidated from various experimental and field studies. This study consolidates the efforts of 22 research projects conducted from 2008 to 2024, incorporating a total of 10,500 mosquito specimens from 12 countries across 5 continents (Fig. 1). Various methods were used to collect the mosquitoes, including CO2-baited traps (n = 4,614), aspirators (1,630), ovitraps (308), egg-raft collection (1,683), and rearing from breeding facilities (2,113). Most of the sampled mosquitoes were identified as female (n = 9,049), with a smaller proportion being male (1,425). Species identification was primarily conducted using morphological methods (n = 4,658)4 or molecular techniques such as COI/nad4 gene barcoding (1,914)25, ITS2 gene barcoding for the identification of Anopheles species (621)26 and qPCR targeting CQ11 and ACE2 genes to identify the taxa morphologically identified as Culex pipiens s.l./torrentium (2,092)27. The remaining samples were identified based on their association with a laboratory colony (1,839).
Geographic distribution of images in the dataset. Countries colour-coded by the number of images (A). Panel (B) shows the mosquito sampling locations in Europe and (C) sampling locations in Southeast Asia. We included both Europe and Asia in the figure due to their higher variance in sampling locations compared to Africa and South America.
The complete wing dataset comprises specimens from nine genera: Culex (n = 3,980), Aedes (5,029), Anopheles (1,135), Coquillettidia (141), Culiseta (158), Uranotaenia (1), Armigeres (49), Mansonia (6), and Toxorhynchites (1). Many mosquito species are difficult or impossible to identify based solely on morphology. However, the dataset includes specimens from such groups, which were identified using morphological characteristics alone. Thus, to present the taxonomic information in a machine-readable format, we developed a hierarchical system of taxonomic levels that also describes the uncertainties in species identification (Supplementary Table 1). The first level corresponds to the family, the second level to the genus and the fourth level to species. The third taxonomic level encompasses morphologically very similar species pairs (e.g. Ae communis/Ae. punctor), species groups (e.g. Ae. annulipes group), species complexes (An. maculipennis s.l.) or combinations of these aggregated taxa (e.g. Cx. pipiens s.l./Cx. torrentium). The species names (fourth taxonomic level) for these specimens were assigned only when the identification was confirmed through molecular assays. Information on subspecies or biotypes is presented under the fifth taxonomic level.
Wing preparation and image capture
Wings were removed from mosquitoes with tweezers under a stereo microscope. The wings were placed on a microscopic slide and embedded in Euparal (Carl Roth, Karlsruhe, Germany) with a cover slide for long-term storage. Detailed instructions on the wing removal process are provided in the supplementary material (see supplementary material: wing_removal_instructions.pdf). In total 18,104 images were captured using different stereomicroscopes and a smartphone with an attached macro-lens. Most images (n = 12,462) were captured using the Olympus SZ61 (Olympus, Tokyo, Japan) in conjunction with the Olympus DP23 camera (Olympus, Tokyo, Japan), followed by 3,577 images with the Leica M205c microscope (Leica Microsystems, Wetzlar, Germany) and 1,685 images using an iPhone SE 3rd generation (Apple Inc., Cupertino, USA) in combination with a macro-lens taken at 24x magnification (Apexel-24XMH, Apexel, Shenzhen, China). The images were captured in TIF format, with resolutions of 3024 × 3024 for smartphone images, 3088 × 2076 for Olympus DP23 images and 2560 × 1920 for images captured using the Leica M205c. Imaging settings were not standardized and thus varied between image collection projects in parameters not further recorded, e.g. exposure time or lighting conditions (Fig. 2). The images captured with the stereomicroscopes are displayed with a scale providing a reference for wing size measurements such as wing length.
Example wing images of different projects of Ae. aegypti from the dataset. Images 2a, 2 d, 2e and 2 f were captured using the Olympus SZ61, 2b was captured using Leica M205c and 2c was captured using an iPhone SE with an attached micro-lens.
