Tropical wasps memorize friendly faces

Tropical wasps have a knack for faces that helps them protect their nests from intruders, scientists report February 4 in the Proceedings of the Royal Society B.

Using varying sight and smell stimuli, scientists introduced alien wasps to 50 Liostenogaster flavolineata colonies in Malaysia. Female guard wasps failed to catch some intruders based on smell alone, and going simply on sight, they mistakenly attacked nestmates. Taking advantage of both senses, the wasps strike a compromise: They recognize scents and unique facial markings of friends and foes, but sight trumps smell.

L. flavolineata aren’t the only wasps that can spot a mug. Read SN’s feature on facial recognition in animals.