Cezário, R. R., Gorb, S. N., & Guillermo-Ferreira, R. (2022). Camouflage by counter-brightness: the blue wings of Morpho dragonflies Zenithoptera lanei (Anisoptera: Libellulidae) match the water background. Journal of Zoology, vol. 317, pp. 92– 100. https://doi.org/10.1111/jzo.12955
From mammals to bugs, a number of animals (and even vegetation) exhibit hanging iridescent colors. Iridescence, an optical phenomenon of structural origin (i.e., micro- and nanostructures on the floor of an animal), is characterised by its color altering with viewing angles. Furthermore, the brightness of the iridescent colors displayed by animals rely on the visible background and ambient mild circumstances the place they dwell.
Therefore, animals might exhibit particular behavioural shows in particular circumstances to boost the visibility of their colors, whether or not to draw mates or keep at bay rivals. Moreover, though counterintuitive, iridescence might operate to keep away from predators by background matching. Birds, fishes, reptiles and, particularly, the Morpho dragonfly Zenithoptera lanei (Anisoptera) profit from this protecting operate of iridescence as they turn out to be much less distinctive (i.e., cryptic) from glossier backgrounds.
For example, Z. lanei, a Neotropical dragonfly inhabiting the Brazilian savannah (i.e., Cerrado), mix their brilliant iridescent colors with a singular wing-clapping show. Each wing surfaces of the Morpho dragonfly exhibit a remarkably brilliant iridescence, UV-blueish on the dorsal floor, whereas black-reddish on the ventral floor. Moreover, Z. lanei can fold their wings dorsally (the one different anisopteran able to folding their wings dorsally is the Australian Cordulephya).
After observing this distinctive behaviour, in addition to the colors of Z. lanei, we requested ourselves if (i) the iridescent colors of Z. lanei wings operate as a visible technique to scale back wing detection by their brightness matching the background; and (ii) the detection of the wings towards vegetation and water varies in accordance with their predators, prey, and conspecifics.
By mathematically modelling the visible system of avian predators, dipteran prey, and conspecifics, we discovered proof that Z. lanei males are in a position to exhibit their angle-dependent iridescence in a spatiotemporal dynamic method.
The angle-dependent iridescence of the wings of Z. lanei males match the brightness of the background they’re naturally discovered wherein disrupts their silhouette for predators, prey and rivals. Nevertheless, by displaying particular behaviours (such because the wing-clapping) towards particular backgrounds and light-weight circumstances, Z. lanei is ready to management when and the place to indicate its colors.
To our data, that is the primary research exhibiting that animals could possibly match, as an example, the brightness of inland-water backgrounds. Particularly, the iridescent colors of Z. lanei wings, which additionally exhibit diffuse reflection, enable males to keep away from undesirable conspecific interactions and detection by prey in addition to by visual-oriented chicken predators.
Rhainer Guillermo-Ferreira