Wing Variability in Some Andean Brown Lacewing Insects as an Adaptive Survival Strategy (Insecta, Neuropterida, Neuroptera: Hemerobiidae)

TL;DR

Some Andean brown lacewing insects use wing variability to avoid predators, increasing their survival by making it harder for predators to recognize them.

Contribution

This study demonstrates that wing variability in Hemerobiidae species increases environmental entropy, serving as an effective anti-predatory survival strategy.

Findings

Natural wing patterns of Hemerobiidae species increase image entropy, making them harder to detect.

Artificially colored wings reduce entropy, making insects more visible to predators.

Greater morphological and chromatic diversity in wings leads to higher entropy and better crypsis.

Abstract

The family of brown lacewings (Neuroptera, Hemerobiidae) shows many strategies of crypsis, including a brown general body; disruptive, dark variegated or maculated wings; falcate wings; and so on. On this basis, some species present a real marked variability in the shape and size of their wings, as well as a remarkably wide variation in wing coloration patterns, which do not seem to be affected by their geographical distribution, sex, or age. This variability makes it more difficult for a potential predator to learn a certain wing model to locate. In this contribution, we demonstrate the efficacy of such variability as an anti-predatory strategy used to maximize the survival and reproductive success of the species by avoiding or minimizing the risk of potential visual identification by predators.

The variability in shape and coloration patterns associated with strategies of crypsis increases the environmental entropy and makes it more difficult for a potential predator to learn a certain prey to locate. To demonstrate this concept, we composed images of the wings of two Hemerobiidae species (Gayomyia falcata and Megalomus stangei) on a leaf background and then optically analyzed them by calculating the entropy of the images (in color as well as grayscale). For comparison, we colored the wings of Hemerobiidae artificially, and the analysis was repeated with these non-cryptic wings. The results indicate that the artificially colored wings reduce the entropy of the image, facilitating the location of the specimen, while the natural wings increase the entropy, thus hiding the presence of the specimen. In this context, the more morphological and chromatic diversity that the wings show, the greater the increase in entropy.

Figures