first_imgNewspaper lining the bottom of a stink bug (Podisus maculiventris, pictured, with eggs at bottom) cage may seem an unlikely impetus for scientific discovery, but it was the black and white squares of the crossword puzzle that that led Paul Abram, an entomologist working towards his Ph.D. at Université de Montréal in Canada, to suspect that stink bugs might be employing a surprising strategy when laying their eggs. Plenty of animals, like birds and other insects, lay eggs that differ in color based on what their parents eat or other factors, but scientists have never observed mothers intentionally changing the color of their eggs. Abram noticed that the eggs on the dark squares tended to be darker and vice versa. Although camouflage might be a tempting explanation for the phenomenon, subsequent experiments, in which the stink bugs were given only white fabric to lay their eggs on, revealed that the pigments served a different function. According to research published today in Current Biology, female stink bugs can change the color of their eggs depending how much light is reflecting off a surface by selectively adding a dark pigment. Because of the pigment’s ability to absorb UV light, the researchers believe that its function is to protect the delicate DNA and cellular machinery inside the developing bug. Abram likens it to sunscreen. In the wild stink bugs lay their eggs on leaves, and additional experiments showed that the bugs placed darker eggs on the top (in direct sunlight), whereas eggs on the shaded underside of the leaf contained 2.1 times less pigment on average. The identity of the pigment is still unknown, but early experiments suggest that it may be related to melanin—the most abundant dark pigment on the planet.last_img