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An infestation of a Cimicidae (Hemiptera: Cimicidae) member, especially the bed bug, can cause economic loss and impact health. A cost-effective and user-friendly method for identifying the infesting species will help with the early detection and control of infestations. A linear morphometric method is often used, but it requires the examination of many characters and a highly preserved specimen. We conducted a comparative morphometric study of the effectiveness of Cimicidae classification using a single organ, the pronotum, through outline-based and linear morphometric methods. Bat ( Stricticimex parvus ), human ( Cimex hemipterus ), and bird ( Paracimex sp.) ectoparasites were subject of the study. With both methods, the properties of size and shape were compared and used separately to classify the specimens. Classification analyses of the two methods provided similar results, but more informative variables of size and shape were obtained with the outline-based approach. Size, as analyzed with the outline-based method, could detect sexual dimorphism, and produced better reclassification. The shape variables obtained from the linear measurements were strongly influenced by size variation, much more than the ones obtained from coordinates describing the pronotum contours. Our data suggest that the outline-based approach provides better characterization variables, thus we recommend them for a wider use in other Cimicidae family members.

Accurate identification of mosquito species is critically important for monitoring and controlling the impact of human diseases they transmit. Here, we investigate four mosquito species: Aedes aegypti , Ae. albopictus , Ae. scutellaris and Verrallina dux that co-occur in tropical and subtropical regions, and whose morphological similarity challenges their accurate identification, a crucial requirement in entomological surveillance programs. Previous publications reveal a clear taxonomic signal embedded in wing cell landmark configuration, as well as in the external contour of the wings. We explored this signal for internal cells of the wings as well, to determine whether internal cells could uniformly provide the same taxonomic information. For each cell to be tentatively assigned to its respective species, i.e., to measure the amount of its taxonomic information, we used the shape of its contour, rather than its size. We show that (i) the taxonomic signal of wing shape is not uniformly spread among internal cells of the wing, and (ii) the amount of taxonomic information of a given cell depends on the species under comparison. This unequal taxonomic signal of internal cells is not related to size, nor to apparent shape complexity. The strong taxonomic signal of some cells ensures that even partly damaged wings can be used to improve species recognition.