This week’s North Carolina insect is a beautiful lepidopteran, Diaphania hyalinata (Linnaeus, 1767), commonly referred to as the melonworm moth. As you might predict, based on its common name, this species feeds on melons and other cucurbits and can be a pest.

This moth was originally described by Carl von Linné in 1767 as Phalaena Geometra hyalinata, from specimens collected in “America”. The lectotype specimen is housed in the Linnean Collection in London, along with three other specimens. None are clearly labeled as being from the New World (one is even interpreted as being from Sierra Leone!). This species has a number of synonyms, including: Phalaena Pyralis marginalis Stoll, 1781, Pyralis lucernalis Hubner, 1796, Phakellura hyalinatalis Guenee, 1854, Pyralis sapillitalis Weyenbergh, 1873, and Phalaena Geometra hyalina Berg, 1875.

This smallish moth (2.5 cm wingspan) seems to be an easy one to recognize, with its striking black and white color pattern, especially the black pattern outlining the wings, with whitish-iridescent medial areas. The clump of hair-pencils (those long, hair-like structures) at the tip of the abdomen is also a noticeable characteristic of males (though common in many other moths species, as well). Some closely related species look very similar, however, and one really needs to dissect out the genitalia to confirm the species determination.

The greenish caterpillar of Diaphania hyalinata, which has two white stripes down its back, can be found feeding on the underside of certain Cucurbitaceae leaves, for example on squash or melon plants.Adult males can often be found wagging their abdomens around, spreading pheromones with their hair-pencils and trying to lure females. Because of their pestiferous nature we know a fair bit about their pheromones, phenology, behavior, and natural enemies (predators and parasitoids), and there is a lot of extension literature available about this species. Adult D. hyalinata are apparently not attracted to lights.

This species can be found throughout the eastern USA, from Ontario to Florida, west to Texas and south to Central and South America. Specimens in the NCSU Insect Museum were mostly collected in Florida, where Diaphania hyalinata (Linnaeus, 1767) is relatively common, and the coastal plain and other parts of eastern North Carolina.

• Diaphania hyalinata (Linnaeus, 1767) species page at BugGuide.
• Diaphania hyalinata (Linnaeus, 1767) species page at GBIF.
• Diaphania hyalinata (Linnaeus, 1767) specimens in the NCSU Insect Collection.
• Phalaena Geometra hyalinata original description in: Linné, Carl von. 1767. Systema naturae, per regna tria naturae :secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Vindobonae [Vienna] :Typis Ioannis Thomae