Rove beetle

Biocontrol Agent

These predatory beetles are beneficial to farmers and gardeners, because they can reduce pest populations, also referred to as biological control, however, because rove beetles are generalist predators, they can also reduce populations of beneficial insects such as beneficial predatory mite eggs and nymphs. This article focuses on Aleochara bilineata, although there are many other species of rove beetles.

Common Names

Rove Beetle

Relative effectiveness

Adult rove beetles may not emerge in spring until several weeks after the overwintering root maggot adults emerge. This is too late to suppress early season crop damage, although late season parasitism of cabbage maggot pupae may sometimes be as high as 90% to 95%.

Where to use

Any crop, inside or outside

Adults are found on the surface and within soil, and on the surface of pest-infested plants. Larvae can be found in leaf litter, soil and decaying plant or animal matter. One species (not A. bilineata) can be purchased for release in greenhouses, and many others can be conserved outside.

About Rove Beetles

Many insect pests are preyed upon by adult rove beetles in the soil, and on the surface and folds of plant foliage where they can be ambushed by lurking adults. The adults are predators, while the first instar larvae parasitize maggot puparium for the purpose of overwintering. Rove beetle adults are generalist predators that feed on a variety of insect pests such as; thrips, caterpillars, mealybugs, mites, nematodes, mosquito larvae, aphids, gnats, grubs, and other insects. These predatory beetles are beneficial to farmers and gardeners, because they can reduce pest populations, also referred to as biological control, however, because rove beetles are generalist predators, they can also reduce populations of beneficial insects such as beneficial predatory mite eggs and nymphs. This article focuses on Aleochara bilineata, although there are many, many other species of rove beetles.

  • Native/Non-native: Native

  • Preferred climate: sub-tropical, cold tolerant

  • Region: Rove beetles occupy almost all moist environments throughout the world.

  • Established: Yes

  • Where established: Rove beetles occupy almost all moist environments throughout the world.

 

Eggs

A. bilineata eggs are oval, about 0.5 mm long and 0.4 mm wide, and are covered with a gelatin-like material which is pale green at first and turns darker after a few days.

First instar

First instar (smallest) larvae are pale brown, about 1.5 mm long, slender, segmented, and tapered with a large head.

Second and third instar

The parasitic second and third instar (larger) larvae are white, have simplified legs, and are found within the host puparium.

How to use rove beetles for biocontrol

Biocontrol category: Conservation—attract and protect from the surrounding environment

When to use: There is only one species of rove beetle commercially available. Support of natural populations is the best way to increase predation of pests in your area. Adult rove beetles may not emerge in spring until several weeks after the overwintering root maggot adults emerge. Natural populations of this species of rove beetle will likely emerge in spring several weeks after overwintering root maggot adults emerge.

Maximizing effectiveness: The presence of crop pests can frequently be critical to attract populations of beneficial insects, because they require an adequate food source to successfully develop and reproduce.

Pest stage: eggs, larvae, or adults, depending on pest

Mode of action: Predator in the adult stage and parasite in the larval stage.

Conservation: Rove beetles are found under debris and rocks, near water, in compost and piles of decaying material, or in the crop canopy. The adults have been found in sweet corn tassels and silks late in the season. Managing hedgerows, shelterbelts and other vegetation may help provide protection for adult beetles and potentially overwintering locations for larvae. Applications of broad-spectrum insecticides should be avoided when possible. For general information about conserving natural enemies, see the Xerces Society.

Compatibility: Laboratory tests showed A. bilineata to be highly susceptible to pyrethroid insecticides. A strain of A. bilineata selected for tolerance to cyclodiene-type insecticides proved successful as a natural enemy of cabbage maggots in Canadian trials in the 1960's. In a 1980 field study, the insecticide chlorfenvinphos used in conjunction with A. bilineata successfully controlled cabbage maggots, although parasitism was reduced. A study in 2002 demonstrated A. bilineata susceptibility to spinosad spray and granule treatments, and another study in 2011 concluded that certain contact pesticides (dichlorvos, and chlorpyrifos-methyl) can be used with rove beetle species in systems that benefit from rove beetles as natural enemies. However, further studies are needed to fully understand the physiological impact of pesticide use on rove beetle species in agricultural settings. 

Any time you use a pesticide, you must read and follow the label directions and comply with all applicable laws and regulations related to pesticide use. Also be sure that any pesticide used is approved for use in your country and state/province.

Commercially available: No—Although A. bilineata is not available, a different species of rove beetle (Atheta coriaria) is currently commercially available through a few common vendors. They are shipped as adults and are intended to be used for the control of fungus gnats, thrips and other soil-dwelling pests, especially in greenhouses. Adults are likely to remain near the release site if prey are available.

Relative effectiveness: A. bilineata adults may consume up to five root maggot larvae per day—a pair may destroy 1200 eggs and 130 larvae, and during their lifetime their offspring may parasitize several hundred pupae. Adults are cannibalistic, eating their own eggs and attacking other adults when food supplies are low.

Adult rove beetles may not emerge in spring until several weeks after the overwintering root maggot adults emerge. This is too late to suppress early season crop damage, although late season parasitism of cabbage maggot pupae may sometimes be as high as 90% to 95%. In one field study, parasitism ranged between 30% and 70%.

A. bilineata has been mass reared in Russia, Europe, and Canada for control of root maggots. It may therefore be feasible to mass release adults at the beginning of the season to increase predation and parasitism of the first generation of root maggots.

Pests Targeted by Rove Beetles

Rove beetles are known to target insect pests in the larval stage such as maggots, caterpillars and grubs while other pests species are targeted in the adult stage (aphids, mealybugs, mites). A pair of adult rove beetles can consume as many as 1200 root maggot eggs in a single day. Adults can be cannibalistic, eating their own eggs and attacking other adults when food supplies are low.

List of Pests Targeted

Aphids • Caterpillars • Grubs • Mealybugs • Nematodes • Mites • Other insect eggs • Root maggot • Onion maggot • Cabbage maggot • Fungus gnat larvae • Thrips • Springtails • Mosquito larvae

 

Tan bug with translucent segments on orange and brown background.

Rove Beetle Larva

Cream colored stem with tan maggots on and within it.

Onion maggot feeding damage on allium shoot

Root, cabbage, and onion maggot damage

Feeding damage and tunneling caused by insects such as the root and cabbage maggot can constrain healthy plant growth in many regions of the world. The damage associated with these pests typically occurs in the roots, tubers, shoots, and leaves of plants and can result in loss of yield. Control of these pests can be achieved using multiple pest management tools, however biological control is one such tactic that reduces the risk of negative environmental effects. Although root, cabbage, and onion maggot are the primary pests attacked by rove beetles, aphids, caterpillars, grubs, gnat larvae, nematodes, mealybugs, mites, and other insect eggs are known to be attacked by adult rove beetles.

Learn More about Rove Beetles

Staphylinidae: The Rove Beetle Family

The rove beetles are the largest North American beetle family accounting for about 63,000 described species worldwide (Betz and Klimaszewski 2018, Weithmann et al. 2020). Most species are predaceous as adults and parasitize maggot puparia in the larval stage to overwinter. Rove beetles can commonly be found in leaf litter, detritus, and organic matter and are one of the most numerous colonizers of carrion (Bohac 1999). Hence, rove beetles are an important and species-rich insect group contributing to the essential ecosystem service of carrion decomposition (Weithmann et al. 2020). 

About A. bilineata

A. bilineata is a species of rove beetle that is known to prey upon species of root maggot (Anthomyiidae), cabbage maggot (Delia radicum), and onion maggot (Delia antiqua). Most rove beetle adults are predators that feed on Dipteran eggs and maggots and parasitize Dipteran pupae (Benbow et al. 2015). However, there are many other pest species that fall prey to rove beetles such as nematodes, mites, gnats, aphids, thrips, mealybugs, caterpillars, etc. For this reason, the rove beetle, Atheta coriaria (Kraatz) is now a commercially available biological control agent (BCA) used against fungus gnats (Warner and Getz 2008, Echegaray and Cloyd 2012).

Detailed Appearance Information

Adult A. bilineata are glossy black with short coarse hairs and are about 5-6 mm in length. They have very small, reddish-brown, inconspicuous forewings beneath which the membranous hindwings are elaborately folded. The forewings look like pads on the upper abdomen. The long abdomen is held aloft like a scorpion if the beetles are disturbed. Well-developed "jaws" cross in front of the head of both adults and larvae. Adults are active, strong fliers. Eggs are oval, about 0.5 mm long and 0.4 mm wide, and are covered with a gelatin-like material which is pale green at first and turns darker after a few days. First instar larvae are pale brown, about 1.5 mm long, slender, segmented, and tapered toward the anterior. They have large heads. The parasitic second and third instar larvae are white, have rudimentary legs, and are found within the host puparium.

A. bilineata Life Cycle

A. bilineata overwinters as a first instar larva within a host puparium. Two days after mating, females begin laying tiny, whitish elliptical eggs—about 15 per day with an average of 700 per season. Eggs are deposited in the soil among the roots of root maggot-infested plants. Larvae hatch in about 5 to 10 days and actively search for root maggot puparia in the surrounding soil. The larva punctures the host puparium, enters, and begins feeding. The entire host pupa is consumed. Although two or more larvae may occasionally enter the same puparium, only one will survive to maturity. A. bilineata pupates within the host puparium and emerges as an adult after 30 to 40 days. The overwintering larvae emerge in the second half of July, and the second generation emerges at the end of August or in early September. Adults live 40 to 60 days, and the life cycle, from egg to adult is about 6 weeks. There may be two generations per year.

Behavior and effectivness of A. bilineata Adults

A. bilineata adults may consume up to five root maggot larvae per day—--a pair may destroy 1200 eggs and 130 larvae, and during their lifetime their offspring may parasitize several hundred pupae. Adults are cannibalistic, eating their own eggs and attacking other adults when food supplies are low. Adult rove beetles may not emerge in spring until several weeks after the overwintering root maggot adults emerge. This is too late to suppress early season crop damage, although late season parasitism of cabbage maggot pupae may sometimes be as high as 90% to 95%. In one field study, parasitism ranged between 30% and 70%.

Rearing and releasing A. bilineata

A. bilineata has been mass reared in Russia, Europe, and Canada for control of root maggots. It may therefore be feasible to mass release adults at the beginning of the season to increase predation and parasitism of the first generation of root maggots.


Pesticide Susceptibility and Potential Integration with A. bilineata in Cabbage Maggot Control

Laboratory tests have shown A. bilineata to be highly susceptible to pyrethroid insecticides. A strain of A. bilineata selected for tolerance to cyclodiene-type insecticides proved successful as a natural enemy of cabbage maggots in Canadian trials in the 1960's. In a 1980 field study, the insecticide chlorfenvinphos used in conjunction with A. bilineata successfully controlled cabbage maggots, although parasitism was reduced. A study in 2002 demonstrated A. bilineata susceptibility to spinosad spray and granule treatments, and another study in 2011 concluded that certain contact pesticides (dichlorvos, and chlorpyrifos-methyl) can be used with rove beetle species in systems that benefit from rove beetles as natural enemies. However, further studies are needed to fully understand the physiological background of pesticide use on rove beetle species in agricultural settings.

Supporting local populations of rove beetles

Although one species of rove beetle is commercially available, supporting local populations of rove beetles can also contribute to increased predation. Supporting populations of natural enemies involves maintaining diverse habitats, as well as planting varieties of flowering plants that offer essential nectar, and pollen that can frequently be critical to some natural enemy survival. Although rove beetles do not require a diet of pollen or nectar, these diverse plants can provide a habitat for rove beetles and support other species of natural enemy.

Broad spectrum insecticides and Rove Beetles

Due to the pesticide susceptibility of Staphylinid species, the use of broad spectrum insecticides is generally not encouraged in locations with many beneficial arthropod species (Cisneros et al. 2002). For more information about conserving natural enemies, see the Xerces Society

Author

Lidia Komondy
Cornell University Department of Entomology

Date: April 2022

I would like to thank the Cornell University Department of Entomology Extension Outreach Program for their support.

Modified from an article written by Dr. Tony Shelton: Shelton, A.M. Aleochara bilineata (Coleoptera: Staphylinidae), Biological Control: A guide to Natural Enemies of North America.

  • Benbow M.E., Tomberlin J.K., Tarone A.M. 2015. Carrion Ecology, Evolution, and Their Applications. 1st ed. CRC Press; Boca Raton, FL, USA.
  • Betz O., Irmler U., Klimaszewski J. 2018. Biology of Rove Beetles (Staphylinidae): Life History, Evolution, Ecology and Distribution. 1st ed. Springer International Publishing; Cham, Switzerland. 
  • Bohac J. 1999. Staphylinid beetles as bioindicators. Agric. Ecosyst. Environ. 74:357-372.
  • Cisneros, J., Goulson, D., Derwent, L., Penagos, D., Hernandez, O., and T. Williams. 2002. Toxic Effects of Spinosad on Predatory Insects. Biological Control. 23. 156-163.
  • Colhoun, E.H. (1953) Notes on the stages and the biology of Baryodma ontarionis Casey (Coleoptera: Staphylinidae), a parasite of the cabbage maggot, Hylemya brassicae Bouché (Diptera: Anthomyiidae). Can. Entomol., 85: 1-8.
  • Echegaray, E.R., and R.A. Cloyd. 2012. Effects of Reduced-Risk Pesticides and Plant Growth Regulators on Rove Beetle (Coleoptera: Staphylinidae) Adults, Journal of Economic Entomology, 105(6): 2097-2106.
  • Finlayson, D.G., Mackenzie, J.R., and Campbell, C.J. (1980) Interactions of insecticides, a Carabid predator, a Staphylinid parasite, and cabbage maggots in cauliflower. Environ. Entomol., 9: 789-794.
  • Hoffmann, M.P. and Frodsham, A.C. (1993) Natural Enemies of Vegetable Insect Pests. Cooperative Extension, Cornell University, Ithaca, NY. 63 pp.
  • Read, D.C. (1962) Notes on the life history of Aleochara bilineata (Gyll.) (Coleoptera: Staphylinidae), and on its potential value as a control agent for the cabbage maggot, Hylemya brassicae (Bouché) (Diptera: Anthomyiidae). Can. Entomol., 94: 417-424.
  • Samsoe-Peterson, L. (1985) Laboratory tests to investigate the effects of pesticides on two beneficial arthropods: a predatory mite (Phytoseiulus persimilis) and a rove beetle (Aleochara bilineata). Pest. Sci., 16:321-331.
  • Warner K.D. Getz C. 2008. A socio-economic analysis of the North American commercial natural enemy industry and implications for augmentative biological control. Biol. Control45: 1–10.
  • Weithmann, S., Kuppler, J., Degasperi, G., Steiger, S., Ayasse, M., & von Hoermann, C. 2020. Local and Landscape Effects on Carrion-Associated Rove Beetle (Coleoptera: Staphylinidae) Communities in German Forests. Insects, 11(12), 828. 
  • Whistlecraft, J.W., Harris, C.R., Tolman, J.H., and Tomlin, A.D. (1985) Mass-rearing techniques for Aleochara bilineata (Coleoptera: Staphylinidae). J. Econ. Entomol., 78: 995-997.
  • Wishart, G. (1957) Surveys of parasites of Hylemya spp. (Diptera: Anthomyiidae) that attack cruciferous crops in Canada. Can. Entomol., 89: 450-454.
  • Rove beetle feeding: Guido Bohne.
  • Rove beetle life cycle: Image used with permission from Hoffmann M.P. and Frodsham A.C. Natural Enemies of Vegetable Insect Pests. Cornell Cooperative Extension. 1993.
  • Onion maggot feeding damage on allium shoot: Riley Harding and Brian Nault
  • Rove beetle larvae: Katja Schulz
  • Adult rove beetle: Katja Schulz
Portrait of Amara Dunn
Amara Dunn-Silver

Senior Extension Associate

NYS Integrated Pest Management

Amara Dunn-Silver
Lidia Komondy

PhD Student

Department of Entomology

Lidia Komondy
  • lmk275 [at] cornell.edu