Australian processionary caterpillars, Ochrogaster lunifer Herrich‐Schäffer (Lepidoptera: Notodontidae), comprise cryptic species

• Published in: Austral entomology 2019-11, Vol.58 (4), p.816-825
• Main Authors: Mather, Andrew, Zalucki, Myron P, Farrell, Julianne, Perkins, Lynda E, Cook, Lyn G
• Format: Article
• Language: English
• Subjects: Acacia; Amnionitis; bag shelter moth; Butterflies & moths; Canopies; Canopy; Caterpillars; coalescence‐based species delimitation; COI pseudogene; Cryptic species; Deoxyribonucleic acid; Dermatitis; Divergence; DNA; Gene flow; Genomes; Health problems; Horses; Host plants; Hosts; Larvae; Mitochondria; mPTP; Nests; Nucleotide sequence; NUMT; Reproductive isolation; Setae; Species; Sympatry; Teara contraria
• ISSN: 2052-174X; 2052-1758
• DOI: 10.1111/aen.12410

The bag shelter moth, Ochrogaster lunifer Herrich‐Schäffer, 1855 (Thaumetopoeinae), is abundant and widespread throughout Australia where its larvae have been reported to feed mostly on Acacia and eucalypts. The larvae, known as processionary caterpillars, build silken nests on their host plants either on the ground at the base of the plant (Acacia) or above ground on the trunk or among the canopy (Acacia and eucalypts). The caterpillars are medically important in that they shed tiny setae that can cause dermatitis and other health problems in humans and other mammals, including amnionitis and foetal loss in horses. Despite reports of behavioural, ecological and morphological differences between ground and canopy nesters, caterpillars of all nest types and hosts are currently considered to belong to one species. Here, we use DNA sequence data from the mitochondrial and nuclear genomes of caterpillars taken from different nest types in eastern Australia to determine whether there is evidence for there being more than one species. We find significant genetic divergence between caterpillars from different nest types despite occurrence in sympatry at multiple sites, indicative of a lack of gene flow and the presence of at least two reproductively isolated species. Given the range of hosts and nest locations within hosts throughout Australia, further sampling is needed to determine just how many species there are under the current concept of O. lunifer.