What's That Bug? does not endorse extermination

small bug infestation
Location: Brisbane, Queensland, Australia
January 18, 2011 8:55 pm
Over the last 2 months, we’v e been finding these little critters dead on our floors. Looks like they’re getting in via cracks under door, or through flyscreens, etc.
We’ve never seen a living one – they’re always dead (we get the house sprayed every year) – but we can find up to a hundred dead on the floor every few days. (more close to a door, thinning out futher into a room). They are up to a centimetre in length. What are they ??
Hope you can shed some light.
Cheers,
Andrew.
Signature: Curious.

Lawn Shrimp

Dear Andrew,
These are known Lawn Shrimp or Househoppers,
Arcitalitrus sylvaticus, a terrestrial Amphipod that is native to Australia.  They are not usually noticed until they enter homes in large numbers and promptly die.  According to BugGuide, the natural habitat is:  “Moist soil and organic matter within 13 mm of the surface, often among ivy or other ground covers, mostly eucalyptus. Their exoskelton has no waxy coating to keep moisture in, so they can’t survive dryness. They drown in water, though, so they need continuously moist, but not waterlogged conditions.”  The torrential rains and flooding in Australia we are reading about is causing the Lawn Shrimp to flee the landscaping around your home.  They are just coming in out of the rain.  BugGuide explains:  “These are rarely seen except when flooding or lack of moisture forces them to abandon their home in the soil in search for suitable conditions. At such times they often end up dieing on pavement or in homes and become a nuisance. Once they start appearing, there’s not much that can be done except to sweep them up- pesticides are pointless, bcause by then they’re already dieing or dead.  The best solution is to keep the numbers down the rest of the year by keeping the soil from staying too moist- in California, especially, they’re a sign of overwatering. Physical barriers like weather-stripping can also help to keep them out of homes, but their bodies are flat and narrow, allowing them to slip through surprisingly narrow cracks.”  Interestingly, we found more written about Lawn Shrimp on North American websites than on Australian websites.  You can read more about them on the Museum Victoria website where they are called Land Hoppers.

Lawn Shrimp

wow – thats fantastic. Thanks very much for tracking that down.
Now that I know what they are, it all makes sense and I know what we’ll need to do to help reduce their numbers.
Much appreciated, and many thanks Daniel.
cheers,
Andrew.

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What's That Bug? does not endorse extermination
Location: Australia

10 Responses to Lawn Shrimp in Australia

  1. Dahogg says:

    Thank you so much for this information. We’re in Warrandyte, Victoria, and are plagued by these for the first time in 30 years. Every morning we have thousands dead on our tiled floor. Have tried Mortein bombs but to no avail. I guess we just have to keep vacuuming them up each day until the long summer sets in and they go away. Had spent a while trying to find out what these were and finally found your site and great explanation and pictures. Many thanks.

  2. sharon says:

    Thanks for that information. We now know what they are!

    We are finding quite a few dead ones each morning around two sliding doors to outside.

    My husband wants to know, do you think it would be beneficial to spread a layer of lime on the concrete outside of the sliding doors? We have no pets and no children (left the nest)!

    Many thanks.

    • bugman says:

      We don’t understand why you want to use the lime. Many gardeners use lime. According to Backyard Gardener: “The main reason for using lime is to reduce the acidity of a soil that is acid or, in other words, to sweeten the soil. Few plants will grow well in a very acid soil mainly because their intake of plant foods is reduced; phosphates, in particular, get ‘locked up’ in acid soils. There is often a shortage of calcium in very acid soils.”

  3. sharon says:

    ps should have added to above post that we are in Currumbin on the Gold Coast.

  4. Jann says:

    Thank you so much for this explanation. I have been finding these in one room in the house right near the back door. I have never seen these before and I am so happy to finally know what they are and that there is no need for concern, except for a mess on the floor every morning.

  5. David says:

    It may be of interest to you to know that we found a couple of dozen of these little critters on our bedroom floor in Berry South Coast of N S W for the first time this week. We have had a LOT of rain over the last few of weeks.

  6. Celso Ferrarini says:

    Had these many years ago in the 80s . Never saw them again. I live in São Paulo Brazil. They invaded the slated floor after a period of heavy summer rain. Cheers!

  7. Deidre says:

    Thank you so much for this information. Have been finding these weird little bugs all over the dining room floor near the back door on & off over the last few months. Had spent quite a while trying to find out what these were and finally found your site and great explanation and pictures. We live in western Sydney where we haven’t had that much rain but had been watering more due to the extra hot weather. Many thanks.

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