DOI: 10.5061/dryad.p6030
title: Data from: Mechanical and tactile incompatibilities cause reproductive isolation between two young damselfly species

description: External male reproductive structures have received considerable attention
 as a cause of reproductive isolation (RI), because the morphology of these
 structures often evolves rapidly between populations. This rapid evolution
 presents the potential for mechanical incompatibilities with
 heterospecific female structures during mating and could thus prevent
 interbreeding between nascent species. Although such mechanical
 incompatibilities have received little empirical support as a common cause
 of RI, the potential for mismatch of reproductive structures to cause RI
 due to incompatible species-specific tactile cues has not been tested. We
 tested the importance of mechanical and tactile incompatibilities in RI
 between Enallagma anna and E. carunculatum, two damselfly species that
 diverged within the past ~250,000 years and currently hybridize in a
 sympatric region. We quantified 19 prezygotic and postzygotic RI barriers
 using both naturally occurring and lab-reared damselflies. We found
 incomplete mechanical isolation between the two pure species and between
 hybrid males and pure species females. Interestingly, in species pairs for
 which mechanical isolation was incomplete, females showed greater
 resistance and refusal to mate with hybrid or heterospecific males
 compared to conspecific males. This observation suggests that tactile
 incompatibilities involving male reproductive structures can influence
 female mating decisions and form a strong barrier to gene flow in early
 stages of speciation.
description: CercusVertexCoordinatesThis folder contains the x,y,z coordinates for points (vertices of a triangular mesh) covering 3-D digitized cerci obtained from CT scans. There is one file for each specimen. Files formatted as Matlab files for morphometric analysis using Spherical Harmonics but files can be read in a text editor.CercusVertices.zipLandmarkCoordinates_malesThis file contains the x,y,z coordinates for 7 common points on each male cercus, to accompany the data in the folder "CercusVertices" for Spherical Harmonic analysis.PCA_malesPrincipal Component Analysis results after Spherical Harmonic Analysis was performed on male cercus data ("CercusVertices" and "LandmarkCoordinates_males.txt". These data are plotted in Figure 3A of the accompanying paper.PlateMorphologyThis folder contains the x,y,z coordinates of points on female mesostigmal plates used for 3-D geometric morphometric analysis, plus results of the analysis and files describing which landmarks are fixed and which are semi-sliding.BodySizeAbdomen length (males and females) and cercus volume (males) of field-caught and lab-reared E. anna, E. carunculatum, and their hybrids.RearingDataData collected on lab-reared individuals and clutches to estimate postzygotic reproductive isolating barriers.Rearing.zipCrosses and behaviorThis file contains data from observing mating attempts, copulations, and any eggs produced after mating.Crosses.txtRI_CalculationsThis file contains formulas used to calculate the strength of reproductive isolation across multiple types of barriers, as described in Sobel and Chen (2014).