What's That Bug? does not endorse extermination

Mating Pill Bugs
May 22, 2010
I read online that this is rarely observed – don’t know if that’s true or not but I’m sending it to you in case you didn’t have it documented on your website. Keep up the good work.
Tim
Memphis, TN

Mating Pill Bugs

Hi Tim,
Thanks so much for contributing your wonderful images to our website.  We really appreciate the generosity of the Wildlife Theater website.  It seems strange that this would be such an uncommonly observed activity since there is no shortage of Pill Bugs in our own garden.

Update:  March 10, 2019
We just received a comment from Prigot which states:  “I’m sorry to inform you pillbug doesn’t mate in this way.. mostly for this specie able to roll in ball. Here they are having antennae contacts. The reproductive behavior is easily recognizable since male are placed on one side of the females and then on the other side. The reason is simple: females have two genital openings on the ventral side and males have two penises. So mating occurs in two stages on either side of the female. If the male is above as shown in the picture, it cannot reach the openings of the females.”  So, we are mistaken about this being mating activity.

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What's That Bug? does not endorse extermination
Location: Memphis, Tennessee

10 Responses to (Not) Mating Pill Bugs

  1. mister marmot says:

    I just observed this behavior on the concrete steps outside the backdoor after a night steady light rain in northern St. Louis. They appear to be Trachelipus rathkei. Their antennae were not obvious (they have them tucked under?) and the curled under section with the pleon’s appeared to be the antennae so I was thinking this was an attack because the heads were fighting. Now that I understand what the pleon’s are it’s obviously mating. My two look nearly identical with the smaller darker shelled crustacean on top of a more mottled brown larger crustacean.

    I can tell you the process is not quick. They have been at it for 15 minutes so far. The female is moving forward and backwards in an attempt to get away. While not actually trying to throw the male off when she walks away more quickly he will sometime lose his grip a bit and then will aggressively curl under her and manipulate with his pleons and rear legs to lift her posterior off the ground.

    They are under a glass container to limit their range for she is eagerly trying to move along. I’ll reply with the final time of completion.

  2. mister marmot says:

    Well, the male was at it for at least 45 minutes and upon the next check-up the proved that they are powerful enough to raise up a clear quart Tubbaerware container and escape.

  3. Heather says:

    Yesterday, I created a timelapse that featured a pair of mating pill bugs (not sure the species — Vista, CA): https://www.youtube.com/watch?v=c55rLz_cME4

    • mister marmot says:

      Thanks for the time lapse video.

      That’s what I witnessed under my porch.

      So it’s not mating but some kind of male dominance of his preferred female?

      Could that happen with two males or females?

      The bug underneath is missing an antenna.
      I can’t tell if the bug above is feeding during the time on top.

      This maybe a method to pass beneficial bacteria between members although it seems that they may eat droppings.

  4. clay says:

    I know this may not be a comment related to pill bug mating but I just witnessed a pill bug or sow bug litghin up after dark it appears to be emitting a low to medium whitish light what are they doing when that happens ?

  5. Prigot says:

    Hi everyone, I’m sorry to inform you pillbug doesn’t mate in this way.. mostly for this specie able to roll in ball. Here they are having antennae contacts. The reproductive behavior is easily recognizable since male are placed on one side of the females and then on the other side. The reason is simple: females have two genital openings on the ventral side and males have two penises. So mating occurs in two stages on either side of the female. If the male is above as shown in the picture, it cannot reach the openings of the females.

    Good continuation to all!

  6. Pyreck Leck says:

    Hey how do pill bugs actually mate though? Can I get a picture?

  7. Lauren says:

    I just saw a pill bug crawl on top of another. The bottom one immediately rolled up while the other moved around on top for over 5 minutes (my toddler got bored so we left). Was this an attack? Sorry no pictures!

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