Prawns in the house?

Question: I don’t live near the beach but keep finding prawns in my house – why?

Answer: These invertebrates are not prawns but a species of amphipod, commonly called land hoppers or lawn shrimps. There are thousands of species of amphipods, the majority of which live in the marine environment. However a number of species are terrestrial and they all require a moist environment in which to survive.

Amphipods are laterally compressed meaning they are taller than they are wide. It may be for some of the marine species that this aids in moving through dense plants. If you have ever lifted a pot plant or raked through leaf litter in a forest or even your garden you may have noticed these land hoppers jumping around. They can achieve this by a sudden flexing of their abdomen and the random and rapid way in which they jump around makes it hard for predators to catch them.

Amphipods are an important food source for many animals in the sea and on land; amphipods themselves generally feed on decaying plant material but there have been some cases of cannibalism.

Sometimes following heavy rain amphipods can be flushed from their usual home in leaf litter and end up coming into peoples homes or garages or falling into their swimming pools. Usually on coming inside they rapidly dry out and die and many become a red or pink color, again contributing to people thinking of them as prawns or shrimps. These invertebrates should not cause any damage to the contents of a house and present more of a nuisance value than anything else. If they come inside and die, simply sweep them up and throw them out.

Try not to have moist, deep leaf litter near doors as this may encourage populations of amphipods and if you get repeat incursions of amphipods into your home try making the cracks under the door smaller by using draught excluders.

References

Melbourne’s Wildlife: a field guide to the fauna of Greater Melbourne.
Published by Museum Victoria and CSIRO Publishing, 2006.

Comments (8) popular  |  oldest  |  newest

Discovery Centre 29 Sep 2011 15:17

Hi Loretta, these creatures can be hard to keep out, have a read of the last couple of paragraphs which has some suggestions on how to try and keep these invertebrates out of the home. Remember that even if they do come in, they pose a nuisance value only, they don't bite people and usually die very quickly after coming into homes. If this does happen you can just sweep up the bodies and throw them out.

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Discovery Centre 09 Mar 2012 14:42

Hi Nina, we have never heard of these amphipods being a problem for dogs. Terrestrial amphipods are usually found in moist areas, feed on decaying plant matter and don't live on dogs. I doubt that they would seek the dog out; has it been lying in mulch or something similar. Are you sure the bites are from amphipods and not fleas or ticks.

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Discovery Centre 20 Mar 2012 09:22

Hi Lisa, terrestrial amphipods generally feed on decaying plant matter and require a moist environment to survive. They would not survive in dry dog food and I doubt would be attracted to it. It may be that the dog has been scratching around its water dish and disturbing the amphipods. When they are exposed they jump in the air and may be ending up in the water bowl? If the dog were to drink a few of these they shouldn't pose any risk.

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