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Cecropia Moths Mating

Cecropia moths (Hyalophora cecropia) are the largest native North American moths. They are members of a group of moths known as giant silk moths (family Saturniidae), renowned for their large size and showy appearance.

Having overwintered as pupae inside silk cocoons they spun (as larvae) in the fall, the adults emerge at this time of year often during the first spell of hot, humid weather by dissolving one end of their cocoon with their saliva.  The female Cecropia emits pheromones at night that are so strong that males can detect them with their feathery antennae from as far as a mile away.  Once paired, Cecropia moths proceed to mate for a full day before parting company. 

Shortly thereafter the female moth lays up to 100 eggs, often on both sides of a leaf. Due to a lack of functional mouth parts and no digestive system, the adults seldom live more than two weeks after mating. (Photo: female Cecropia moth on left (larger abdomen filled with eggs; narrow antennae); male on right (smaller abdomen; broader, more feathery antennae). Many thanks to Lorraine Vorse for photo opportunity!

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Note that mating took place very near the (female’s) cocoon (lower right).

8 responses

  1. Noreen

    What type of shrub/tree is the cocoon on? Do they attach it to a larval host plant?

    May 24, 2021 at 7:38 am

    • Hi Noreen,
      Yes, they often do attach to a larval host plant, in this case a young birch, but not sure which species!

      May 24, 2021 at 8:01 am

  2. Alice

    I really like the easier way to identify males & females in this species. With other moths & butterflies you need to get close, to see wing colors, dots. Beautiful photo., their addomins are gorgeous.

    May 24, 2021 at 8:36 am

    • Alice


      May 24, 2021 at 4:35 pm

  3. Robin Worn

    An amazing photo! Shows so much in one shot. Thank you Mary, and thank you Lorraine!

    May 24, 2021 at 9:07 am

  4. Cindy Sprague

    Those are such great photos! Thank you for sharing.

    May 24, 2021 at 11:28 am

  5. Truly amazing Mary. I am in awe.

    May 24, 2021 at 8:51 pm

  6. Wonderful photo and info! A whole day… my goodness!
    Do they lay eggs on any special types of leaves?
    And what do the larvae feed on? (I could look up this info, I suppose…
    Okay, from what I just found, it seems that they don’t particularly specialize re. food for larvae – it just says “leaves of trees of bushes.”
    It also says that they have so many enemies/predators that they never become pests. That’s nice to know, because they certainly are spectacular!

    May 25, 2021 at 12:16 am

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