The Featured Creatures collection provides in-depth profiles of insects, nematodes, arachnids and other organisms relevant to Florida. These profiles are meant to be used by both casual readers who are interested in biology and students.
The Featured Creatures collection provides in-depth profiles of insects, nematodes, arachnids and other organisms relevant to Florida. These profiles are meant to be used by both casual readers who are interested in biology and students.
Amphipods comprise an order of crustacea, shrimp-like in form, which contains mostly marine and freshwater forms. While some species are terrestrial, they still require moist habitats. These terrestrial species are sometimes referred to as lawn shrimp due to their similarity to true shrimp.
Amphipods were first described in New South Wales, Australia, and then later on several Pacific islands. One species was found in California in 1918, which was the first time they were seen in the Western Hemisphere (Mallis 1990). About 90 species occur in the United States and Canada. Nationally, the best known terrestrial species that occasionally invades structures is Arcitalitrus sylvaticus (Haswell) (McLaughlin et al. 2005, Smith and Whitman 1992). Two species common to Florida are Talitroides topitotum (Burt) (W. Cranshaw personal communication 30 June 2011) and Talitroides allaudi (Chevreux).
Have you ever noticed tiny, shrimp-like creatures hopping around your lawn after heavy rain? These little critters are actually known as lawn shrimp, and they can be a common sight in yards and gardens. In this article, I’ll explain exactly what lawn shrimp are, what they look like, how they live and reproduce, whether they’re harmful, and how to control them if you want to get rid of lawn shrimp.
What Are Lawn Shrimp?
Lawn shrimp, also sometimes called yard shrimp or grass shrimp, belong to a group of small crustaceans called amphipods. There are around 10,000 species of amphipods worldwide, most of which live in water. However, some species like lawn shrimp have adapted to live on land in damp environments.
Specifically, lawn shrimp are in the family Talitridae, which contains around 300 species globally They are closely related to sand hoppers or sand fleas which you sometimes see on beaches.
Lawn shrimp are not actually true shrimp, but they do resemble tiny shrimp in appearance. They belong to the subphylum Crustacea along with other crustaceans like shrimp, crabs woodlice and water fleas.
Unlike their marine cousins, lawn shrimp require moist habitats and cannot survive in dry conditions. They are found in areas with damp soil, leaf litter and decaying vegetation.
What Do Lawn Shrimp Look Like?
Lawn shrimp are very small, just 3 to 8 mm long when fully grown (around 1/8 to 1/3 inch). They are elongated in shape, kind of torpedo or cylindrical shaped. They are flattened from side to side, almost like someone sat on them!
Their bodies are divided into segments, with the head, thorax (mid-section) and abdomen (tail-end) clearly visible. They have a curved body, with the tail curling under the body slightly.
Lawn shrimp vary in color. When alive, they range from pale brown to greenish brown, but sometimes with orange or reddish tones. However, after death they usually turn more pinky-red in color.
Some key features to recognize lawn shrimp:
- Two pairs of antennae – one long pair and one short pair
- Bulging eyes on either side of the head
- Seven pairs of walking legs attached to the thorax
- No hard shell or covering over their body
Lawn shrimp move by making little hops and jumps, similar to fleas. This makes them tricky to catch! Their ability to jump gives them the alternate name “hoppers”.
Where Are Lawn Shrimp Found?
As lawn shrimp require moisture, they are found living in damp micro-habitats such as:
- In leaf litter, compost and mulch
- Underneath dense ground cover plants
- Among lawn thatch
- Under logs, pots and trash cans
- In shady, moist flower beds
- Near leaky outdoor faucets or hoses
Lawn shrimp may also temporarily migrate into garages, pool areas or homes during very wet weather if their usual habitat becomes overly saturated. They soon die indoors as it is too dry for them there.
In the US, lawn shrimp are found nationwide but are more common in humid climates. They were first reported in California in 1918 and around 90 species are now established in the US and Canada.
The Life Cycle and Habits of Lawn Shrimp
Lawn shrimp hatch from eggs as tiny replicas of the adults. There is no larval stage. Females carry the eggs in a pouch under their bodies until they hatch into juveniles after 1-3 weeks.
Most species produce only one generation per year. The young shrimp leave the female’s pouch after her first molt following mating. They reach adult size in 2-8 weeks. Adults may live for around one year.
Lawn shrimp are generally nocturnal or active at dawn and dusk. During the day, they tend to stay hidden in moist refuges. They feed on decaying plant material and fungi, helping to recycle nutrients back into the soil.
If their habitat dries out, they become active during daylight as they migrate across lawns and sidewalks looking for moister areas. Lawn shrimp need moisture to breathe through gills on their legs, so dry conditions can be fatal.
Are Lawn Shrimp Harmful?
Lawn shrimp are completely harmless to people, pets, plants and lawns. They do not damage or eat living plants. They do not bite or sting.
In fact, lawn shrimp are beneficial for gardens as they break down decaying matter and their droppings help fertilize the soil. They are an important part of the ecosystem and food chain, providing food for birds, spiders and centipedes.
The only problems lawn shrimp sometimes cause are nuisance issues:
- Large numbers hopping on driveways look unpleasant
- They can clog pool filters if they fall in the water
- They may invade garages and homes in wet weather, dying indoors
But in general, lawn shrimp do not cause any real harm in gardens and are considered more of a nuisance than a true pest.
How to Get Rid of Lawn Shrimp
Lawn shrimp are easily controlled by reducing moisture in their habitat. Here are some tips:
- Allow leaf litter and thick ground cover to dry out between waterings
- Rake up decomposing matter frequently
- Remove excessive mulch buildup
- Improve drainage in chronically wet areas
Also:
- Seal gaps under doors to prevent entry into buildings
- Keep pool areas free of damp debris
- Clean pool filters frequently during rainy periods
There are no pesticides labeled for lawn shrimp control. Changing their environment is the best way to discourage them.
Insect growth regulators and nematodes are sometimes advertised to kill lawn shrimp but there is little evidence they work well. Avoiding moisture is more effective.
When Are Lawn Shrimp Most Active?
Lawn shrimp activity increases at certain times of year when conditions are favorable:
- In spring, as temperatures warm and soil moisture increases
- In late summer/early fall during the wetter part of the year
- After heavy rains, when soils become saturated
- During prolonged damp, humid weather
Lawn shrimp numbers drop when the habitat dries out, such as during droughts or dry seasons. Cold winter temperatures also reduce their activity and survival.
Frequency of entities based on content:
Lawn shrimp – 73
Shrimp – 16
Amphipods – 7
Talitridae – 2
Arcitalitrus sylvaticus – 0
Talitroides topitotum – 0
Talitroides allaudi – 0
Description and Life Cycle
Amphipods are elongate and more or less compressed laterally. They don’t have a carapace, which is a hard covering on the thorax that other crustaceans have. Also, seven (rarely six) of the thoracic segments are separate and have appendages that look like legs. Most of the body is made up of thoracic segments because the abdominal segments are fused together (Borror et al. 1989). They have two pairs of antennae, with one pair usually very small. The eyes usually are well developed, but are sometimes reduced or lacking. Members of this order have chewing mouthparts (Smith and Whitman 1992). Adult amphipods range from 5 mm to 20 mm (3/16 to 3/4 inch) in length. The Haswell species Arcitalitrus sylvaticus is 8 mm (3/8 inch) long, the Topitotum species is 7 mm long, and the Allaudi species is about 3 mm long. 5 mm. Aquatic species are often whitish but are seen in other colors also. Petals of land species range in color from light brown to greenish to brownish black when they are alive. When they die, they often turn pink to red.
Amphipods are sometimes misidentified as springtails (Insecta: Collembola). Springtails are commonly found in moist areas, sometimes in vast numbers. However, springtails are not crustacea. Instead, they are arthropods that look like insects and have only three pairs of legs, one pair of antennae, and a furcula (a forked structure) on the fourth abdominal segment. A group of springtails that could be mistaken for amphipods has a tube-like structure on the last part of their abdomen.
Eggs are deposited within a brood pouch on the underside of the adult female amphipods body. The eggs hatch in one to three weeks. It takes about seven to eight days for the young amphipods to leave the pouch after the female has her first molt during mating. They look like adults. The molt usually takes about one hour. Also, most species go from eggs to adults in less than a year (Smith and Whitman 1992).
Most species only lay one brood of eggs, but in the aquatic species Hyalella azteca, the females lay an average of 15 broods over the course of five months. Hyalella azteca is common in water systems and is used by scientists to check the health of the environment and the quality of water in streams, lakes, and other bodies of water.
Beach fleas and other amphipods like them live on the beach, where they hide under rocks or dead plants. Most amphipods are scavengers. Mallis (1900) found amphipods living under ivy used as ground cover. Here they jumped about like fleas and were difficult to capture. Amphipods are present in soft ground up to a depth of 13 mm. Leaf mold beneath shrubbery also offers a suitable habitat for terrestrial amphipods (Mallis 1990).
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. Amphipods do not have a waxy layer on their exoskeleton as do insects. They lose or gain moisture from their environment. Too much of a water loss results in desiccation, while too rapid a gain is also lethal. This is why they leave areas with wet soil for areas with dry soil, where they usually die anyway. Most species are active at night.
Terrestrial amphipods need wet places to live and die quickly in dry places like buildings or pavements that are drying out. They may be safely swept or vacuumed up and discarded. There are no labeled insecticidal recommendations for control.
If amphipods are always a problem on sidewalks, pavements, or open structures after it rains a lot, the mulch or ground cover near these areas should be turned over or watered less to get rid of the existing populations. This is similar to the practice used to control fungus gnats in indoor ornamental plantings. Weather stipping on the bottom of doors helps in keeping amphipods from entering structures.
Amphipods can cause problems for pool owners. During rainy weather, large numbers can be found in swimming pools and these can clog pool filters. Regular cleaning of filters during this period is the only solution.
Borror DJ, Triplehorn CA, Johnson NF. 1989. An Introduction to the Study of Insects. Harcourt Brace Jovanovich Publishers. 875 pp.
Lowry JK, Springthorpe RT. (September 2001). Amphipoda: Families. Crustacea.net. http://www.crustacea.net/crustace/amphipoda/index.htm (delinked 23 October 2012).
Lowry J. (December 2010). Arcitalitrus sylvaticus (Haswell, 1879). World Register of Marine Species. http://www.marinespecies.org/aphia.php?p=taxdetails&id=555665 (12 December 2014).
McLaughlin PA, Camp DK, Angel MV, Bousfield EL, Brunel P, Brusca RC, Cadien D. 2005. Common and Scientific Names of Aquatic Invertebrates from the United States and Canada: Crustaceans. American Fisheries Society Special Publication 31. pp. 545.
Pinto LJ. 1990. Occasional Invaders. In Handbook of Pest Control. Story K, Moreland D (eds. ). Franzak & Foster Co. Cleveland. 1990. pp. 833-867.
Smith EH, Whitman RC. 1992. Field Guide to Structural Pests. National Pest Management Association. Dunn Loring, VA.
Release Date:June 17, 2021
- DOI: doi.org/10.32473/edis-in377-2001
- Critical Issue: 1. Agricultural and Horticultural Enterprises
This document is EENY-220, one of a series of the Entomology and Nematology Department, UF/IFAS Extension. Original publication date July 2001. Revised October 2010, August 2011, and December 2014. Reviewed March 2021. Visit the EDIS website at https://edis. ifas. ufl. edu for the currently supported version of this publication. This document is also available on the Featured Creatures website at http://entnemdept. ifas. ufl. edu/creatures/.
Thomas R. Fasulo, retired scientist, Entomology and Nematology Department; UF/IFAS Extension, Gainesville, FL 32611.
Amphipod Facts: the LAWN SHRIMP Animal Fact Files
What are lawn shrimp?
Lawn Shrimp: What Are They, And Should You Be Concerned If You Find One? Lawn shrimps (aka fairy shrimps, grass shrimps, lawn prawns, or land hoppers), scientifically known as land-based amphipods, are intriguing and often misunderstood creatures that can be found in gardens and lawns.
What is the difference between prawn and shrimp?
Shrimp and prawns have plenty of similarities, but they are not the same animal. Their differences involve their biology. Shrimp bodies are encased in a sort of accordion shell, with a membrane between the segments. Prawns have a shell where each segment overlaps the one below it. There are no big differences between them when it comes to their nutritional value; they are both a good source of protein, and relatively low in calories.
Are lawn shrimp aquatic?
While most amphipods are aquatic in freshwater or marine environments, lawn shrimp are terrestrial, dwelling in soil and mulch. Aquatic relatives of lawn shrimp can be seen in the Louisiana lakes and swamps, especially in the roots of water hyacinth (Pontederia crassipes). They are common in the lakes around the LSU campus.
Are lawn shrimp a prawn?
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.