Mosquito Alert Dataset

There is no pre-set sampling frequency: participants can send as much data as they like wherever and whenever they like or can. Data sampling may be more intense in some periods due to dissemination events (e.g. project appearances in TV, Science Fairs, etc.) but is also naturally modulated by mosquito seasonal prevalence and activity patterns.

There are no limitations in terms of geographic areas from which citizen are allowed to participate, so data can be sent from all over the world. Nevertheless, Mosquito Alert’s main coverage has been in Spain, with increasing coverage in Europe since 2020, mainly in The Netherlands, Italy, and Hungary. The temporal coverage of the dataset is from June 18, 2014 to September 20, 2021.

The Digital Entomology Network is formed by a number of experts, including the so-called National Supervisors. At each European country participating through the projects AIM-COST and VEO, the National Supervisors serve as national level coordinators and supervisors. In addition, a senior entomologist Super Expert is in charge of the coordination of the whole validation flow and mechanics in the Mosquito Alert system. A manual for the expert validation system is distributed beforehand to the members of the network and published in the Mosquito Alert website [36] with specifications on the criteria for species determination. The taxonomic determination of an observation results in two potential outputs indicating the degree of certainty: confirmed, when taxonomic features can be clearly seen in the picture/s and probable, when only some characteristic features can be observed. The final taxonomic determination and the relative degree of certainty is computed based on expert’s validations in two steps. (1) Selection of most voted category. The selection for the most voted category is a simple majority selection. For example, assume the following three expert validation assessment: "Probably Ae. albopictus | Definitely Ae. albopictus | Probably Ae. aegypti". The most voted category is Ae. albopictus with two votes. Note that in this step, the "Probably" and "Definitely" qualifications given by each expert are ignored. If there is no majority (i.e, every expert chooses a different taxonomic category) the classification result is considered a "conflict" and the report is flagged and revised by the super-expert. (2) Certainty value selection. The certainty labels of the most voted taxonomic category are mapped to integer values such that 1 corresponds to "Probably" and 2 to "Definitely". The final certainty assessment value is given by averaging the values and rounding them to the nearest integer value with a round half down strategy. For the above example, the most voted category is Ae. albopictus where two values are issued ("Probably" and "Definitely") that results in an average value of 1.5. Finally, after rounding the average to 1 the assessment gives a "Probable" Ae. albopictus occurrence. If the final result would be 2, the certainty degree of the occurrence would be labeled as "Confirmed". Note that rounding half down strategy implies a conservative approach in the certainty evaluation: if one of the expert expresses doubt, the overall value is decreased. The validation procedure allows an expert to label a report with not sure in case of pictures with insufficient information. Those records are not included in the current dataset, since only confirmed or probable mosquito records are valid occurrences. For each record, the corresponding entomologist experts who reviewed it are cited by name or by a group label (e.g. institution, team name, etc.). The Anonymous expert label is assigned to experts who wish to remain anonymous.