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Lovebugs Mating

11-18-16-lovebugs-mh_20091020_004606_2If you see a swarm of small black insects bobbing up and down in the air, you may well be observing the mating ritual of March Flies, also known as Lovebugs. These flies belong to the family Bibionidae, and the majority of species emerge in the spring, hence their common name. (In the Northeast, many appear in April and May.) However, there are certain species which emerge and mate in the fall and they are active now.

March Flies are dimorphic. Males (fly to the left in photo) are easily discernible because of their large eyes, essential for finding mates and chasing competing males. Males comprise most of a swarm, performing an aerial ballet as they bounce up and down, courting females as they emerge from the ground en masse. Once mating has taken place, the male and female of certain species remain attached to one another, even in flight. This is where the name “Lovebug” came from.

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8 responses

  1. Sandy DeRosa

    I saw this beautiful bouncing in the air of these critters.
    Now I know what they are. Thanks!

    November 18, 2016 at 7:44 am

  2. Alice Pratt

    There is always a nice way to describe courtship….and you did!

    November 18, 2016 at 8:14 am

  3. I’ve seen these lately – thanks for the ID!

    November 18, 2016 at 9:16 am

  4. Jon Binhammmer

    Love bugs in the love shack! Sorry, couldn’t help the B-52’s reference.

    November 18, 2016 at 9:49 am

  5. Kathie Fiveash

    How big are these flies?

    November 18, 2016 at 12:05 pm

    • Hi Kathie,
      Roughly between a quarter and half an inch…

      November 18, 2016 at 7:15 pm

  6. Susie

    The flies I have always referred to as “lovebugs” exhibit a red/orange thorax btwn their wings & eyes. I looked the genus up in my Kaufman Field Guide to Insects of North America to see what was written there about “March flies”. This guide seems to separate the “March fly” (Bibionidae femoratus) & “lovebug” (plecia nearctica) as separate of many species in the genus bibio. Do all flies in this genus attach to each other in the way you’ve described?

    November 18, 2016 at 12:37 pm

    • Hi Susan,
      It’s my understanding that all of the genera in the family Bibionidae (Bibio, Dilophus, Hesperinus, Penthetria, and Plecia) are referred to as March flies. You are right, the black and orange species in the genus Plecia are specifically called lovebugs! Thanks for your sharp eye.

      November 20, 2016 at 11:20 am

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