Immature instars of three species of Rhodnius (Hemiptera: Re-duviidae: Triatominae): morphological and morphometric studies

Published: 21 December 2021| Version 5 | DOI: 10.17632/tjgj87yw78.5
Tiago Belintani


This data is of geometric mophometric of the Immature instars of three species of Rhodnius (Hemiptera: Re-duviidae: Triatominae): morphological and morphometric studies


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Geometric morphometrics was used to evaluate variations in head shape and size using Cartesian reference coordinates. Variations among the heads of all nymphal instars of the studied species were evaluated. Fifteen heads of each instar were selected, and the images were obtained by means of a stereoscopic magnifying glass coupled to the Motic Advanced 3.2 plus scanning system. The coordinates of the reference points were selected according to Bookstein [29]. Ten anatomical landmarks of Type 1 (for example, intersec-tion between veins) were collected and processed using the modules available in the tps Dig v.1.18 software [30]. Four anatomical landmarks were digitized for the 1st instar of development and five anatomical landmarks were selected for the other instars of devel-opment; the landmarks being digitized using the CLIC package ( Then the file with the raw coordinates was used for a generalized Procrustes analysis (GPA). GPA is a method that allows eliminating all the information related to size, position, and orientation of previously digitized anatomi-cal frames [30]. The matrix of form was held in a Euclidean space to generate a set of marks known as partial warps [29]. All the additional statistical forms were performed using Procrustes residues to analyze differences in the size and shape of the heads of each nymphal instar. Procrustes ANOVA [31] is used to infer differences between species. These differences in size were assessed using an isometric estimator defined as centroid size (CS) [32]. Mahalanobis distances between pairs of species were calculated for meas-urements of shape and significance was assessed using a non-parametric test based on permutations (bootstrap, 10,000 replications) using MorphoJ [33]. In addition to that, us-ing distance dice from Mahalanobis, neighbor-joining trees (NJ) were recovered using PAST v.3.25 [34]. To determine the relationships between species, canonical variable analysis (CVA) was performed using MorphoJ [33]. CVA was performed associated with a resampling method (bootstrap, 10.000 replications) to build regions of trust in relation to the median size of the species centre. A factorial map of the first two canonical fathers was created using MorphoJ [33] and it illustrates the main results for the species.


Universidade Estadual de Campinas


Natural Sciences