Fig 1.
Scanning electron microscope (SEM) of the two types of vein joints.
Red circle indicated the mobile joint while blue circle, the immobile joint. The illustrated Fig 1(A): Mobile joint at the cross vein attached with the longitudinal vein. (B): Immobile joint at the trailing edge of the wing. (C): Two types of the vein joint in the region of the MP(-).
Fig 2.
Distribution of resilin and spikes in the vein joints of R. fenestrella wing.
A(i) and B(i) indicated dorsal side of the wing, while A(ii) and B(ii) indicated the ventral surface of the forewing. C-D: FM (right) and SEM (left) images at the selected joints for dorsal (upper) and ventral (below) surfaces. (C): Large resilin patches on both dorsal and ventral surfaces. (D): Resilin patches at the mobile joint. (E): No resilin patch at the immobile joint.
Fig 3.
Distribution of resilin and spikes in the vein joints of R. perforata wing.
A(i) and B(i) indicated dorsal surface of the wing, while A(ii) and B(ii) indicated the ventral surface of the forewing. C-D: FM (right) and SEM (left) images at the selected joints for dorsal (upper) and ventral (below) surfaces. (C): Large resilin patch in both dorsal and ventral surface. (D): No resilin patches at the ventral surface. (E): Resilin patches at the mobile joint for both dorsal and ventral surfaces.
Fig 4.
Distribution of resilin and spikes in the vein joints of R. biforata wing.
A(i) and B(i) indicated dorsal surface of the wing, while A(ii) and B(ii) indicated the ventral surface of the forewing. C-D: FM (right) and SEM (left) images at the selected joint for dorsal (upper) and ventral (below) surface. (C): Large resilin patches on both dorsal and ventral surfaces. (D): Resilin patches on both dorsal and ventral surface. (E): Only resilin patch on ventral surface.
Fig 5.
Summary of resilin and spikes mapping for the Rhinocypha group.
(A) Phylogenetic comparison of resilin patches and spikes in damselflies. Branches show the relationship of taxa based on molecular, cytochrome oxidase c subunit 1 (COI) gene. (B) Nomenclature of wing structure according to Riek & Kukalova-Peck [37]. (C) Symbols used for resilin and spikes mapping. “Present” and “Absent” are marked at the vein that showed blue fluorescents and vice versa, and at the vicinity of vein joint for spikes. Findings from Donoughe et al [17]- were added to the figure, and these were indicated by asterisks (*).
Fig 6.
Relation of cuticular spikes with longitudinal vein by SEM imaging.
(A) A spike upright protrusions pointing directly away from the wing surface. (B) A spike placed adjacent to the longitudinal vein. (C) Two types of spikes between cross vein and longitudinal vein. (D) Spikes orientated towards the longitudinal vein which impacted the wing veins.
Fig 7.
Surface of the wing images by SEM.
(A); R. fenestrella, (B); R. perforata, (C); R. biforata. i–iii: the image for wing membrane, mobile joint and immobile joint respectively.
Fig 8.
Morphologies of Rhinocypha spp. wings as observed under AFM.
A(i), A(ii) and A(iii) potray the wing membrane, mobile joint and immobile joint of R. fenestrella; B(i), B(ii) and B(iii) indicated the wing membrane, mobile joint and immobile joint of R. perforata, while C(i), C(ii) and C(iii) indicated the wing membrane, mobile joint and immobile joint of R. biforata respectively.
Table 1.
Calculated values using the Young’s modulus formula for the 3 section wing samples from the 3 species, genus: Rhinocypha.
Fig 9.
Force-displacement curve of the three sections of Rhinocypha spp. with glass as a reference.
(a) represented the force-displacement curve for the species of R. fenestrella, (b) R. perforata, (c) R. biforata respectively.
Fig 10.
Force-indentation curve of the three sections of Rhinocypha spp.
(a) represented the force-indentation curve for the species of R. fenestrella, (b) R. perforata, (c) R. biforata respectively.
Fig 11.
Amino acid composition in the Rhinocypha spp. wings.