Tracing Nemoriini in the New World leads back to the Old World


Jaan Viidalepp, researcher at the Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, has dedicated all his life on researching moths and butterflies. Recently his article A morphology based key to the genera of the tribe Nemoriiniwas published in the journal Zootaxa. Based on material he has collected for more than 50 years, Viidalepp stated that the Nemoriini tribe branched from its Miocene-era ancestors billions of years ago, at the time when the ancient supercontinent Gondwana was splitting. Today they are essentially still the same.

Nemoriini is one of nine tribes of green-coloured looper moths. About thirty genera of nemoriines have specific characters but the adults and their larvae also share some peculiar traits—the larvae have flat dorsal filaments and a cockroach-like appearance. Whilst tracing the geographical distribution of these characters, Viidalepp found them both in the Old World and New World genera.

Invaluable Biological Background

One specific characteristic—apically flat and bilobed uncus (one of the sclerites of the genital armature of male moths)—co-occurs with a multicoloured wing pattern. Genera with such attributes are distributed in the tropical forests of Australia and South America. This combination of characters must antedate the splitting of Gondwana. The further evolution of nemoriines has been divergent on separated continents. The leading trend within the Neotropical genera is simplification both in terms of the external appearance and morphological structures. Larvae have remained the same.

Viidalepp used the comparison of morphological characteristics, which is a kind of old-school method also applied in phylogeography. He sampled nineteen Nemoriini genera, about 200 species, to construct a key.

Phylogeography investigates the taxa in their geographical distribution. Viidalepp studied the geographical distribution of character spectra in the Nemoriini taxa and this can be considered a new approach. “A thorough investigation of the material is required to see the full picture, not a single characteristic,” he explained. According to him, the approach adds to our knowledge about this aspect of nature.

What is more, the morphological approach is important in researching nature because observing numbers only does not allow viewing the biological background—thousands of individual specimens who are to be prepared and investigated, Viidalepp noted.

Collection waits for Further Study

Viidalepp has collected butterflies and moths from all over the world, ranging from Siberia to Australia and South America. As a result, the collection of butterflies and moths in the Estonian University of Life Sciences is the biggest in Estonia—there are samples from about a hundred Lepidoptera families available for further study.

Viidalepp plans to continue his research in the same manner. He has chosen to follow the principle to collect data until it starts to yield meaningful results.

As the climate changes, it also brings alien species of butterflies and moths to Estonia, while knowing the species helps to deal with them to avoid negative effects, Viidalepp noted. He brought the example of Lymantria dispar, the gypsy moth, which is a serious pest in terms of agriculture and deciduous forests that has entered Saaremaa. The moth’s pheromone can be synthesized artificially, and this has been used to confuse its mating patterns and lead male moths into traps.

In 1994 lepidopterologists launched a regular monitoring network to register the phenology of nocturnal moths in Estonia and the changes in their abundance.

This article was funded by the European Regional Development Fund through Estonian Research Council.

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