Color and Iridescence in the Stinkbug

“Beautiful” may not be the first word to describe the stinkbug, but Tectocoris diopthalamus sure are pretty. Pictured above are six specimens, three females (first row) and three males (second row). Do you notice a difference? Hint: it’s all in the colors.

Like mallards, narwhals, and peacocks, T. diopthalamus are sexually dimorphic, meaning that the females and males of the species look physically different. In a new study published last week in PLOS ONE, researchers state that male stinkbugs of this species are more likely than their female counterparts to have large, iridescent patches and to be a deeper shade of red. These eye-catching characteristics may help males attract females and even scare off predators. The colors are variable, however, and subject to a number of environmental factors.

In the study, the researchers used electron microscopy and pigment analysis to study how this stinkbug produces the colors you see above. They identified a type of melanin, which partly make up the blue-green iridescent patches. They also identified a nitrogen-heavy pigment called erythopterin, which produces the orange-red color.  High temperatures and a shortage of nitrogen-rich foods have the potential to affect these respective pigments and lead to a wide range of colorful variations. Neat!

Citation: Fabricant SA, Kemp DJ, Krajíček J, Bosáková Z, Herberstein ME (2013) Mechanisms of Color Production in a Highly Variable Shield-Back Stinkbug, Tectocoris diopthalmus (Heteroptera: Scutelleridae), and Why It Matters. PLoS ONE 8(5): e64082. doi:10.1371/journal.pone.0064082

Image: Image comes from Figure 1 of the research paper.