Piercing Fruit and Piercing Souls

The moths of the superfamily Noctuoidea are one of the most diverse subsections of the Lepidoptera, with probably somewhere between fifty and seventy thousand species known to date (Zahiri et al. 2012; as with other massively diverse clades, the lack of proper checklists and revisions makes the question of species number surprisingly difficult to answer). For many people, the classic image of a 'moth' will evoke a noctuoid: broad-winged, often nocturnal, often predominantly brown or grey in colour. Obviously, a group this size is going to have a complex taxonomy, and one of the significant subgroups of the noctuoids is the tribe Ophiusini.

Variable drab moth Ophiusa mejanesi, copyright Bernard Dupont.

Historically, the classification of noctuoids has been something of a mess. One researcher commented in 1975 that "It is exceptional to find any two authors who use the same combination of subfamily names within the Noctuidae" and Zahiri et al. admitted in 2012 that the validity of this statement still stood. Until recently, the majority of noctuoids were dumped in a broad family Noctuidae but recent studies (particularly influenced by molecular data) have lead to a significant rearrangement. As a result, the Ophiusini went from being usually placed in the family Noctuidae, subfamily Catocalinae, to the family Erebidae, subfamily Erebinae. A number of genera previously included in the Ophiusini were also transferred elsewhere; most notably, these included all New World representatives so the Ophiusini are now regarded as an exclusively Old World group.

Thyas juno, copyright Alexey Yakovlev.

The Ophiusini are mostly robust-bodied moths with wings of a fairly uniform background colour marked with simple, linear lines on the forewings. The males lack well-developed coremata (eversible structures used for dispersing pheromones) on the genital valves. The caterpillars are elongate semi-loopers with the front two pairs of abdominal prolegs much reduced compared to the rear two pairs. Larvae have been recorded from a wide range of host plant families but the most commonly exploited hosts are members of the Combretaceae and Myrtaceae (Holloway 2005). The pupa lacks the waxy bloom found in many other erebines.

Caterpillar of guava moth Ophiusa disjungens, copyright Robert Whyte.

Many members of the Ophiusini also have a modified apex to the adult proboscis bearing strong, enlarged spines and reversed, erectile hooks (Zahiri et al. 2012). This formidable apparatus is used to pierce the skins of fruits, allowing the moth to feed on their juice. As well as damage caused by browsing caterpillars, ophiusins may therefore also be of concern to horticulture due to damage from this fruit-piercing behaviour. As well as the damage caused by the moth itself, the resulting holes may allow the fruit to be attacked by disease or other insects not capable of breaching the rind themselves. The modified proboscis may also function in what is somewhat daintily referred to as lachrymal feeding: the process of applying the proboscis to the eyes of mammals (more rarely birds) and feeding on secreted fluids. Yes, these are moths that can potentially destroy an orchardist's crop... and then proceed to drink his tears.

REFERENCES

Holloway, J. D. 2005. The moths of Borneo (part 15 & 16): family Noctuidae, subfamily Catocalinae. Malayan Nature Journal 58: 1–529.

Zahiri, R., J. D. Holloway, I. J. Kitching, J. D. Lafontaine, M. Mutanen & N. Wahlberg. 2012. Molecular phylogenetics of Erebidae (Lepidoptera, Noctuoidea). Systematic Entomology 37: 102–124.