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Some Moths Behave like Butterflies to Mate

Paysandisia archon (Castniidae)
A study led by ICTA-UAB researcher Víctor Sarto describes a striking example of evolutionary convergence in the order of Lepidoptera. A diurnal moth species has adopts sexual communication rules that are specific to butterflies and has even lost pheromone glands.


A new study led by the researcher at the Institute of Environmental Science and Technology at the Universitat Autònoma de Barcelona Víctor Sarto and colleagues from the Institute of Advanced Chemistry of Catalonia (CSIC-IQAC) has described for the first time in two centuries of knowledge a case of evolutionary convergence in the order of butterflies (Lepidoptera), certainly representing an evolutionary breakthrough to what has been known about their sexual communication. The research has discovered important behaviour and physiological changes in the mating process of the moth Paysandisia archon (Castniidae). This neotropical moth which reached Europe in 2001 from Argentina (also inhabiting Uruguay and Brazil) breaks the known sexual rules by behaving like a diurnal butterfly.

The moth’s behavior was already described as “strange” by scientists when this new species reached Europe by sea, hiding within infested palms in big ship cargoes. For the next 15 years it spread eastward along the Mediterranean basin to other countries and reached Bulgaria, Greece and Cypress, causing considerable havoc among palm trees. Researchers noticed there was something very special concerning this moth. Strangely, the adults (males and females) behaved quite differently to other moths, so much that they acted more like butterflies than moths.

Lepidoptera (butterflies and moths) is one of the most diverse insect groups with currently about 160,000 described species. Within this vast group of insects and until 2012, only two basic partner-finding strategies pertaining to ‘butterflies’ and ‘moths’ were known. In short, in the case of butterflies (which are primarily diurnal) males use their vision to detect conspecific females at some distance and pursue them. Female butterflies, in turn, have no sex pheromone glands in their ovipositors and therefore do not release any long-range pheromone to attract males.

In contrast, in the case of moths (mostly nocturnal), males use their olfactory system to detect females at some distance because the latter release long-range pheromones from their pheromone glands. Once together and in close courtship interactions, males (butterflies and moths), and in some cases also females, release close range pheromones or ‘scents’ that facilitate or hinder the last courtship steps leading to copulation.

The butterflies simply use vision to find mates in their sunlit environment with no need to produce long-range sex pheromones. The moths, in turn, maintain the so-called “female calling plus male seduction” strategy, which implies the production of long-range sex pheromones.

In two papers published in 2012 and 2016, researcher Víctor Sarto demonstrated that this alien moth, Paysandisia archon, breaks the known rules by behaving like a butterfly. Among their abnormal behaviour, it is highlighted that males are territorial, use only vision for partner-finding, females do not release pheromones to attract males and have even lost their pheromone glands (which are normally located in the ovipositor) to the extent that they resemble female butterflies. “All these attributes are new and have no parallel in the world of moths, certainly representing an evolutionary breakthrough to what has been known about sexual communication in Lepidoptera” says Víctor Sarto who states that this evolutionary convergence has taken place since day-flying moths have been subject to analogous evolutionary pressures such as those of butterflies.