It might have been their last kiss — if the lovers had mouths.    

Adult luna moths do not have a mouth or a digestive system, and do not eat during their short seven to ten-day lifespan. In their final embrace, a couple of moths were found in copula, attached and resting on David Hobart’s fence when he captured their intimate encounter.  Luckily, they were not bothered by his voyeurism.  

If Dave’s picture taking had disturbed them, they might have failed in their most important biological imperative, breeding. Luna moths must remain in copula, attached to each other for 24 hours, to be reproductively successful. If they are torn apart before that, fertilization may not be complete.  

Luna moths are large, iconic green insects with long tails and a preference for night flights. Male and female moths fly independently, only getting together to mate. When ready, the female, with her unfertile eggs, will find a resting space and remain for a few days until she is ready for her prince.    

She will beckon to him silently by emitting pheromones. He will have been flying about in a zigzag pattern seeking her signal, and will follow the scent back to her. She will accept him without fuss, as she is not picky and takes her suitors on a first come, first served basis.  

After the required daylong affair, the male will leave and over the next few days the female will oviposit or place her eggs on her preferred vegetation, which can include hickories, birch, walnut, sumac, and sweet gum. The eggs will pass through a liquid mix of fluids that include the male’s sperm — a glue of sorts — and other seminal fluids, creating the perfect fertilized egg packet.  

A female luna moth will lay eggs singly, but has as much as 250 to deposit on her preferred plants. The eggs will hatch after 10 days into green caterpillars that will grow in five stages, called instars.  

Each instar is distinctive, and larger than the one before. As the caterpillar grows, it must shed its skin, which becomes too tight for comfort. The hues vary slightly with each instar, as do other bodily characteristics. The second instar has spiny tubercules or growths, and the fifth instar caterpillar is chubby, after having eaten voraciously in order to store food for its cocoon stage.  

Luna moths are found throughout the country and have different reproductive habits in different regions. In colder climes, they have one generation per season before overwintering in their cocoon, which they make out of silk and wrap in a leaf of a favored tree. Those with one generation are called univoltine. In warmer areas, luna moths can be bivoltine or trivoltine, having two and three generations respectively.  

Consider yourself lucky if you’ve seen these moths and even more fortunate if, like Dave, you have caught them in flagrante delicto. Kiss them goodbye: they will be overwintering in their cocoons. Their offspring will emerge next summer, ready for their brief romantic life — even if they can’t spesak the language of love. 

Suzan Bellincampi is islands director for Felix Neck Wildlife Sanctuary in Edgartown and the Nantucket Wildlife Sanctuaries. She is also the author of Martha’s Vineyard: A Field Guide to Island Nature and The Nature of Martha’s Vineyard.