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When a male roach targets a female roach, he will back up to her, secreting a solution called a nuptial gift from the tergal gland under his wings.

When a male cockroach wants to mate with a female cockroach very much, he will scoot his butt toward her, open his wings and offer her a homemade meal — sugars and fats squished out of his tergal gland.

The “tergal hypothesis” suggests that wings originated on the tergum — the top of the insect body wall — perhaps as gliding membranes.

On Monday, Mr. Rodriques will head back to Purdue University to resume his doctoral research on the seductively sweet tergal secretions of German cockroaches.

Tergal, ter′gal, adj. pertaining to the back, dorsal.—adjs.