yrei

Yrei are bioluminescent, arboreal insects described in Eldaran fantasy and gaming sources as inhabitants of temperate rainforests. They are a common element in world-building and ecology within the setting.

Description and biology: Yrei are 1.5 to 2.5 cm long, with a slender body and two pairs of iridescent wings. They glow softly from bioluminescent bacteria in specialized organs, producing light that intensifies in darkness or during courtship. Adults feed mainly on nectar from night-blooming plants; larvae feed on bark lichen and fungi.

Life cycle and ecology: The species undergoes complete metamorphosis. Egg-laying occurs near flowering plants; larvae pupate in crevices of tree bark. Yrei are important pollinators for several Eldaran nocturnal flora and are prey for insectivorous birds and small mammals. Habitat loss and deforestation threaten local populations.

Taxonomy and distribution: In-world scholars place the Yrei in a dedicated order, Yreiformes, with the family Yreidae; some sources compare them to lepidopterans due to wing structure, leading to ongoing debate. They are endemic to eastern Eldara, typically at elevations between 200 and 900 meters.

Cultural significance and discovery: In Eldaran folklore, Yrei trails of light are associated with ancestral presence and serve as symbols in harvest and solstice rites. The first in-world description appeared in field notes published in 2216 by naturalists Lira Morth and colleagues, with later revisions refining their ecology and behavior in 2237.