Giant Lawn Shrimp: All You Need to Know for a Thriving Garden

Giant lawn shrimp, also known as terrestrial amphipods, are fascinating crustaceans commonly found in gardens and lawns. They inhabit moist areas like the surface of mulch or wet ground, and are usually seen after rainfall when they migrate into garages or under doors of houses ¹.

Despite their name, these small creatures are not actually shrimp but are related to them. They play an essential role in breaking down organic matter and contributing to the health of your garden’s ecosystem. Keep reading to learn all about these intriguing little critters and their fascinating habits.

What Are Giant Lawn Shrimp?

Giant lawn shrimp, also known as terrestrial amphipods, are small crustaceans that can be found in gardens and moist soil. They are not actually shrimp but belong to the same class, Crustacea.

These critters are native to Australia but can be found in various regions around the world. A distinctive feature of lawn shrimp is their brown color, which helps them blend into their environment.

Unlike other crustaceans, lawn shrimp have relatively simple structure:

• They possess two pairs of antennae
• Their bodies are laterally compressed, which means they are flattened from side to side

Giant lawn shrimp inhabit the top layers of moist soil or leaf mold, usually no deeper than 13mm. They particularly enjoy mulch and damp ground.

Here’s a quick comparison of giant lawn shrimp and typical crustaceans:

In conclusion, giant lawn shrimp are small, brown crustaceans that dwell in moist soil and gardens. They have a simple structure and are a unique member of the Crustacea class.

Habitat and Natural Environment

Wetter Climates and Moist Environments

Giant lawn shrimp, also known as terrestrial amphipods, are commonly found in wetter climates and moist environments. These tiny creatures are drawn to areas with high levels of moisture, making them prevalent in places like California during the rainy season. They thrive in moist environments like wet topsoil, mulch, and grass-covered areas. Some key points to note about their habitat:

• Prefers moist and wet environments
• Often found in fertilized soil
• Common in grassy or mulched areas, especially after rain

Decomposing Leaves and Organic Material

These harmless nuisances are known to feed on decomposing leaves and organic material. They play a role in breaking down dead plant matter, contributing to the ecosystem as decomposers. They are often found near areas with leaf litter or decaying matter, such as:

• Beneath layers of dead leaves
• Moist ground covered with organic materials like mulch
• In damp gardens with plenty of decaying plant matter

Here’s a comparison table of their habitat preferences:

While some people may dislike the sight of these amphipods or find them as a mild nuisance, it’s essential to note that they are harmless creatures that do not pose any significant threat or infestation risk to homeowners.

How to Identify Lawn Shrimp

Physical Characteristics

Lawn shrimp, also known as terrestrial amphipods or Arcitalitrus sylvaticus, are small crustaceans with some distinct features. Here is a list of their physical characteristics:

• Exoskeleton: Unlike other shrimps, lawn shrimp don’t have a hard outer shell.
• Flat bodies: Their bodies are flattened from side to side, which helps them move through their habitats.
• Black eyes: These tiny creatures have black eyes, which are easy to spot during close examination.
• Size: They usually live on the surface (top 1/2 inch) of mulch and moist ground, growing up to 13 mm in length ¹.

Behavioral Traits

Understanding the behavioral traits of lawn shrimp will assist you in identifying them. Some of their behaviors include:

• Moisture-seeking: Lawn shrimp thrive in humid, damp environments, such as leaf mold beneath shrubbery or wet ground ¹.
• Migration: After rains or in damp conditions, they may migrate into garages or under doors of houses ¹.
• Nocturnal: Lawn shrimp are mostly active during the nighttime, hiding under rocks or debris during the day.

In conclusion, identifying lawn shrimp mainly involves recognizing their physical characteristics, such as their exoskeleton, flat bodies, black eyes, and size. You should also consider their behavioral traits, such as seeking moist environments, migration, and nocturnal activities, to distinguish them from other creatures.

Do Lawn Shrimp Cause Damage?

Impact on Gardens and Flower Beds

Lawn shrimp, also known as terrestrial amphipods, are small invertebrates that can be found in moist environments, such as gardens and flower beds. They feed on decaying plant materials, making them omnivores. While their presence may initially seem harmful, these tiny creatures actually contribute to breaking down organic matter and can be considered beneficial in some ways.

However, in large numbers, lawn shrimp may cause damage to delicate plants and flowers. They generally do not cause significant damage to healthy and established plants in the garden.

Concerns for Pets and Humans

Lawn shrimp are not known to pose direct threats to humans or pets, as they lack a biting or stinging mechanism. However, some people may be concerned about their pets accidentally consuming these small invertebrates. Fortunately, the carapace of lawn shrimp is hard and unappetizing to most pets, making it unlikely that they would eat them.

It’s essential to avoid using pesticides to control lawn shrimp populations, as the chemicals could be more harmful to your pets than the invertebrates themselves. Instead, consider using non-chemical methods, such as reducing excess moisture in your garden and removing decaying organic materials. This will not only help control the lawn shrimp population, but also promote a healthier garden environment.

Comparison Table: Lawn Shrimp vs. Springtails

Controlling and Preventing Lawn Shrimp Infestations

Pest Control Methods

Lawn shrimp, also known as terrestrial amphipods, are tiny crustaceans that can be found in moist environments in your yard. To control and prevent their infestations, consider the following methods:

• Insecticides: Apply appropriate insecticides to affected areas. Consult with a local expert or garden center for the best product for your specific situation.
• Natural predators: Encourage natural predators, such as birds, by setting up bird feeders or birdbaths in your garden.

Maintaining a Dry and Healthy Garden

Creating an unfavorable environment for lawn shrimp can be an effective way to prevent infestations. Keep the following tips in mind:

• Avoid overwatering: Lawn shrimp thrive in damp areas, so it is essential to prevent overwatering your plants and lawns.
• Proper drainage: Ensure proper drainage in your garden by leveling the area, adding gravel or sand to heavy clay soils, and installing drainage systems if necessary.
• Moisture levels: Regularly check your garden’s moisture levels, especially during wetter climates and periods of inclement weather.
• Remove organic material: Lawn shrimp feed on algae, fungi, and decaying organic material. Regularly clean up wet leaves and debris to reduce their food sources.

Pros and Cons of Lawn Shrimp Control Methods

By adopting these pest control methods and focusing on maintaining a dry and healthy garden, you can effectively reduce the risk of lawn shrimp infestations and keep your outdoor space looking its best.

Interesting Facts and Uses of Lawn Shrimp

Lawn shrimp are actually terrestrial amphipods and are not related to prawns, lobsters, or cooked seafood shrimp. They live on the surface of mulch and moist ground, usually up to a depth of 13 mm. Their habitats can be found in gardens, often beneath shrubbery.

These creatures are also known as beach fleas due to their hopping behavior. They play a significant role in the ecosystem, acting as decomposers and helping maintain soil health. After rains, they might migrate into garages or under doors of houses.

Fish enthusiasts might find lawn shrimp useful as they can serve as live food for their fish tank or ornamental pond inhabitants. These amphipods are a nutritious part of the food chain for creatures like fish and birds.

Comparison table:

Lawn shrimp can be found in certain types of aquarium setups as well, where they assist in breaking down organic matter. However, they’re not suitable for all tank environments.

Pros:

• Provide natural food source for fish and birds
• Help in decomposition process

Cons:

• May enter homes after rain
• Not ideal for all aquariums

In summary, lawn shrimp are interesting creatures that play a role in ecosystems and can provide benefits to fish tank and ornamental pond inhabitants. Just remember to consider their habitat requirements and potential drawbacks before introducing them to your own garden or aquarium.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Lawn Shrimp

small brown crustacean in house
Fri, Nov 28, 2008 at 10:39 PM
I live in Southern CA and we’ve had heavy rain the last few days. Since this morning we are finding small brown bugs that look like a crustacean and kind of like a maggot. They are in the front rooms of the house and on the front patio. Could they be from the rain and what are they? The picture attached is from the web, but the look almost identical. Thanks
Lauren
in house in Southern CA

Hi Lauren,
What a wonderful photo of Arcitalitrus sylvaticus, a Lawn Shrimp, according to BugGuide, or House Hopper, according to Charles Hogue in Insects of the Los Angeles Basin.  According to BugGuide:  “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, because 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. ”

Letter 2 – Lawn Shrimp

Bug identification please
Location: Berkeley, CA
December 19, 2010 8:36 pm
Found these in our finished basement, which is connected by a doorway to an unfinished basement. The dog also goes in there, so stuff from outdoors tends to get dragged in more than in the rest of the house. Area is generally cool, somewhat high humidity. Photos are the same positions, just lit differently. THANKS!
Signature: Earthman

Dear Earthman,
We suspect that with Southern California experiencing the worst storm in the decade, with predictions being in excess of 8 inches of rainfall in less than a week, your letter will be the first of many requesting the identification of Lawn Shrimp, Arcitalitrus sylvaticus, though we also predict that your photo will be among the best we receive.  Lawn Shrimp are terrestrial amphipods that proliferate in the damp conditions of well watered gardens, however, when soaking rains arrive, they often seek shelter indoors where they promptly die and turn pink.  According to BugGuide, they are found in : “Moist soil and organic matter within 13 mm of the surface, often among ivy or other groun covers. 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.”   BugGuide also remarks:  “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.”  Lawn Shrimp, which are also known as Househoppers, are not native to California.  They were introduced from Australia.

Hey, thanks so much for the help. Very informative, and your expert reply is much appreciated. You’re doing a public service. THANKS!

Letter 3 – Lawn Shrimp

Copper colored flat bugs
Location: Los Angeles
October 22, 2010 6:38 pm
Hi. I am desperate to find out what these bugs are that I am finding dead in my house in one particular room. They are flat, but not like bed bugs. They are flat instead from the side. They resemble shrimp. The color is metallic copper with pink accents. Two events coincided with the bugs’ appearance. 1. I opened my sealed wedding dress box which (& this is disgusting) had been invaded by termites). 2. I just bought a bromeliad tropical plant.
I have never seen the bugs alive. they seem to be dropping from the ceiling, but maybe they care just coming from the plant & then being distributed to different parts of the room with foot traffic.
I would be forever grateful if you could help, O kind sage.
Signature: Sarah

October 22, 2010 11:15 PM
Hi!  I looked at your site again & identified my bugs as “lawn shrimp.”  Thank you for your site.  It is wonderful!!!!

Hi Sarah,
We are happy to hear you were able to utilize our extensive archive to identify your Lawn Shrimp without our assistance.  We are posting your photo because we believe the recent rains will probably cause other area residents to notice the terrestrial amphipods, also called House Hoppers, when they seek shelter and die indoors.

Letter 4 – Lawn Shrimp

Help please
Hello,
After the last hard rain 10 days ago, these bugs have been coming out every night, they look black, are about 1/4 inch long and jump around from out of the grass onto my porch. They seem to be attracted to light, because each morning I find hundreds of their little dead copper colored bodies all over my front and back porch. In the 2 years I’ve lived here, I’ve never seen them before. What are they?
Thanks very much from San Dimas, CA
Janet Boydell

Hi Janet,
You are being plagued by Lawn Shrimp, a colorful name for a type of terrestrial Amphipod. Terrestrial amphipods live on the surface (top 1/2 inch) of mulch and moist ground. After rains, large numbers of amphipods can migrate into garages or under the doors of houses. There they soon die their color changing from brown, green or black to red upon death. They migrate out of rain-soaked soil to drier areas where they usually end up dying. Most species are active at night. Here is a site with additional information.

Thank you very much!
Hi and thanks so much for getting back to me. By the way, your website is wonderful…my son thinks it’s so cool that you posted our question and then answered us. Very helpful and useful! I’ll pass it on.
Best to you,
Janet

Letter 5 – Lawn Shrimp

Yard Shrimp
Thanks to your site, I have found that the bug that has been infesting a specific area of my utility room are lawn shrimp. And, as you said in the previous message, indeed we have been having rain here in North Central Florida ( Ocala ). They lay dead by the tens of dozens between my utility room outside door and the cat’s feeding dish. However, there is no sign of them in the food dish itself. I can find no sign of them outside the house or anywhere else in the house. There is no real concentrated pile of them to suggest they have a specific spot where they are staying in my house. I see no signs of them in daylight but just an hour or two after sunset they suddenly appear with many dead and a few dying. They indeed look like tiny rusty colored shrimp. They move slow and appear more black when alive than the rusty brown when dead. Dead or not, it’s not a nice site first thing in the morning. So, now that I have identified the pest thanks to your site, how can I keep them out of my utility room or kill them outside without making a toxic mess that my cat may get into?
Thanks,
Wesley J Burdine
Ocala , Florida

Hi Wesley,
Sorry we can’t help you with any erradication advice, but at least your problem now has a name and you can contact local experts. We couldn’t decide if we liked your backlit picture better than the flash photo, so we posted them both.

I actually found a friendly deterrent to the Lawn Shrimp. While trying to find the least toxic method to control them because of concern mostly for my cat, I first tried the powder that you sprinkle on your carpet to get rid of fleas. I sprinkled some around the doorway and also just off the edge of the concrete walkway. This has deterred the Lawn Shrimp without killing them in the yard.
Thanks much,
Wesley J Burdine

Letter 6 – Lawn Shrimp

Thousands invading after rain
October 15, 2009
We wonder what these are and where they are coming from (most likely). After rains this past 2 years they come in under the door by the hundreds and die on the floor. The backyard patio of covered with their dead bodies.
Creeped Out
Ventura, California, USA

Dear Creeped Out,
This is a terrestrial amphipod known as a Lawn Shrimp or House Hopper.  The behavior you describe is very characteristic.  This species lives in ground covers like ivy, and after a heavy rain, thousands of individuals will seek shelter indoors to die shortly afterward.

Letter 7 – Lawn Shrimp

strange hopping bug…
Location: Orange County California
December 21, 2010 12:06 am
This bug was found by my backdoor. This is the second one I’ve found in 2 days. It has been raining a lot so I’m sure that’s why they’re coming inside. It hops really fast maybe 4-5 inches.
Signature: jon

Hi Jon,
This terrestrial amphipod is commonly called a Lawn Shrimp or House Hopper.  They are generally noticed after a heavy rain.  We usually only receive images of pink dead specimens that have entered homes to escape drowning.  It is an introduced species from Australia.