What Do Beetles Eat?

Beetles have one of the widest dietary ranges of any insect group, and what they eat depends heavily on the species. Many are herbivores, feeding on leaves, roots, seeds, fruit, or wood. Some, like Japanese beetles, thrive on plant foliage and flowers, while others such as root-feeding beetle larvae target the underground portions of plants. A large number of beetle species are decomposers, consuming decaying wood, leaf litter, fungi, and dead animals; these play an important role in breaking down organic material in the ecosystem.

There are also predatory beetles—ground beetles and lady beetles are well-known examples. They actively hunt other insects, mites, and soft-bodied pests like aphids, making them natural pest-control allies. A smaller subset of beetles has highly specialized diets. Carpet beetles, for instance, feed on natural fibers and proteins such as wool, feathers, and dried animal matter. Grain beetles and flour beetles target stored foods, infesting dry goods in pantries or warehouses.

Because the beetle family is so diverse, understanding what a specific beetle eats generally requires identifying the type of beetle first. From there, it becomes much easier to predict its behavior, locate food sources, and determine whether it poses a risk to plants, stored goods, or household materials.

Do Beetles Eat Insects?

Many beetle species do eat insects, and several are highly effective predators. Ground beetles, tiger beetles, and rove beetles actively hunt a wide range of prey, including caterpillars, maggots, aphids, mites, and even other beetles. Lady beetles are especially known for feeding on aphids and scale insects, which makes them valuable for natural pest control. Some predatory beetles target eggs or larvae of other insects, while others scavenge dead or dying insects rather than hunting live ones. The specific diet varies by species, but predation is a major feeding strategy across several beetle families.

What Insects Do Beetles Eat?

Predatory beetles can feed on a surprisingly broad range of other insects, and their targets vary depending on the species and the stage of the prey. Ground beetles often hunt soft-bodied insects such as caterpillars, maggots, grubs, and worms, making them especially active in soil and leaf litter where those pests develop. Lady beetles focus heavily on sap-feeding insects like aphids, whiteflies, scale insects, and mealybugs, consuming both the adults and their eggs. Rove beetles, which are agile and aggressive, pursue small flies, mites, springtails, and other tiny arthropods they can overpower. Some larger beetles, such as certain tiger beetles, will take down ants, small spiders, or even other beetle larvae.

In addition to hunting live prey, many beetles will scavenge dead insects they encounter, especially species that live under bark or in decomposing organic matter. This combination of predation and scavenging helps keep various insect populations in check, which is why many beetle species are considered beneficial in gardens, landscapes, and agricultural settings.

Do Beetles Eat Spiders?

Some beetle species do eat spiders, though it’s not universal. Predatory beetles—especially larger or faster types—are the ones most likely to take on spider prey.

Ground beetles (Carabidae): These are strong, fast hunters that mainly target insects but will also attack small or slow-moving spiders, including juvenile orb weavers or house-dwelling species they encounter on the ground.
Tiger beetles: Known for their speed and aggressive hunting style, they can overwhelm small spiders when the opportunity arises.
Rove beetles: Some species feed opportunistically on spiders, especially spiderlings or weakened individuals found under debris or in soil.

In most cases, beetles will pursue spiders only when the size and situation favor the beetle. Spiders are often formidable predators themselves, so interactions can go either way depending on the species and relative size.

Do Beetles Eat Plants?

Yes, many beetle species eat plants, and plant-feeding beetles make up a large portion of the entire beetle family. Their diets and feeding habits depend on the species, but several well-known groups are strictly or primarily herbivorous.

Leaf feeders: Beetles such as Japanese beetles, flea beetles, and leaf beetles chew holes in foliage, skeletonize leaves, and damage flowers or buds.
Root feeders: Larvae of species like June beetles, masked chafers, and various scarabs live underground and feed on grass and plant roots, often causing turf damage.
Stem and wood borers: Longhorn beetle larvae, bark beetles, and some weevils bore into stems, trunks, or branches, disrupting nutrient flow and weakening or killing plants.
Seed and fruit feeders: Some beetles target seeds, nuts, or fruit. Examples include acorn weevils, seed beetles, and certain sap beetles that invade ripe or damaged fruit.
Stored-product feeders: Flour beetles and grain beetles feed on processed plant material such as grains, cereal, flour, and dry goods.

Because beetles occupy so many ecological niches, knowing the specific species is essential for determining whether it poses a threat to plants, turf, or stored commodities.

What Plants Do Beetles Eat?

Beetles feed on an enormous variety of plants, and the exact targets depend on the species. Many common garden and agricultural beetles prefer soft, nutrient-rich foliage, including roses, fruit trees, vegetables, and ornamental plants. Japanese beetles, for example, feed on more than 300 plant species, ranging from grapes and raspberries to maples and lindens. Flea beetles typically attack vegetables such as eggplant, tomatoes, peppers, cabbage, and other brassicas, creating shot-hole damage in young leaves. Leaf beetles tend to specialize, with different species focusing on willows, elms, cottonwood, milkweed, potatoes, or beans.

Other beetles prefer tougher or concealed plant parts. Scarab larvae (grubs) feed on grass and turfgrass roots, weakening lawns and causing patchy die-off. Weevils are notorious for attacking a wide range of hosts: some feed on roots of ornamentals, others defoliate broadleaf plants like rhododendrons, and still others bore into seeds, acorns, or nuts. Wood-boring beetles such as bark beetles and longhorn beetles target stressed or dying trees, boring tunnels beneath the bark and disrupting the tree’s vascular system.

Because beetles often specialize in particular plant groups, identifying the beetle usually reveals its preferred host plants. That makes it much easier to anticipate damage, choose monitoring strategies, and apply targeted control if needed.

Flesh Eating Beetles

There are several types of beetles that are known for consuming flesh, whether it's the flesh of dead animals, other insects, or in some cases, even living animals. These beetles play essential roles in decomposition processes. Here are some beetles that are associated with flesh consumption:

Carrion Beetles (Silphidae): Carrion beetles are known for their scavenging behavior. They feed on the decaying flesh of dead animals. They often arrive at carcasses relatively quickly to lay their eggs, and both the adults and their larvae feed on the decomposing tissue. The burying beetle is a well-known example in this family.
Hide Beetles (Dermestidae): While hide beetles primarily feed on dry animal products like leather, fur, and feathers, they are sometimes found on decomposing flesh as well. They can be pests in museums, homes, and taxidermy collections.
Rove Beetles (Staphylinidae): Some rove beetles are associated with carrion and may consume decaying animal matter. These beetles are often found in the same environments as carrion beetles.
Necrophagous Beetles: This is a broader category that includes various beetles that feed on decaying matter. In addition to carrion beetles, it encompasses a range of other scavengers and decomposers.
Predatory Beetles: While not strictly flesh-eating, some predatory beetles, like ground beetles (Carabidae), may occasionally consume soft-bodied invertebrates, including the flesh of other insects.

While some beetles are associated with decomposing flesh, they typically do not pose a threat to living animals or humans. Instead, they contribute to the decomposition process, helping to recycle nutrients and maintain ecological balance. Carrion beetles, in particular, are considered beneficial because they help to reduce the presence of dead animal carcasses in the environment.

What Do Boxelder Beetles Eat?

Boxelder beetles, scientific name Boisea trivittata, are primarily herbivorous insects with specific dietary preferences. They are often associated with the boxelder tree (Acer negundo) and feed on various parts of this tree. Here's what boxelder beetles eat:

Boxelder Tree Seeds: Boxelder beetles primarily feed on the seeds of the boxelder tree, which is their preferred and most common food source. They have a strong preference for the seeds, especially those that are freshly fallen or still on the tree. These beetles use their piercing-sucking mouthparts to extract the sap and nutrients from the seeds.
Other Maple Species: While boxelder beetles are most closely associated with boxelder trees, they may also feed on seeds of other maple tree species, such as silver maple (Acer saccharinum) and red maple (Acer rubrum).
Other Vegetation: In the absence of boxelder seeds or other suitable food sources, boxelder beetles may feed on other plant materials, such as leaves, stems, and tender parts of various plants. However, this is less common, and they prefer seeds.

While boxelder beetles primarily feed on plant material, they are not considered significant agricultural or horticultural pests. They are more commonly known for their overwintering behavior, where they seek shelter in homes and other structures during the cooler months, which can be a nuisance to homeowners. Their feeding on boxelder and other maple tree seeds does not typically lead to significant harm to these trees.

What Do Darkling Beetles Eat?

Darkling beetles, which belong to the family Tenebrionidae, are a kind of darkling beetle known for their scavenging and detritivore behavior. Their diet primarily consists of decaying organic matter, but they are opportunistic feeders and can consume a variety of food sources. Here's what darkling beetles eat:

Decaying Plant Material: Darkling beetles are often found in habitats with decaying plant matter, such as fallen leaves, dead wood, and compost piles. They feed on decomposing plant material, helping to break it down and recycle nutrients.
Decomposing Animal Matter: Some darkling beetles, especially larger species, feed on decaying animal matter. This includes carcasses of animals, birds, insects, and other invertebrates.
Fungi: Darkling beetles may also consume various fungi that grow on decaying organic matter. Fungi can be an essential part of their diet, especially in habitats with high fungal activity.
Stored Grains and Crops: Certain darkling beetle species, like the confused flour beetle (Tribolium confusum) and the red flour beetle (Tribolium castaneum), are considered pests in agriculture and can infest stored grains, cereals, and other dry food products. They can cause significant damage to stored food items.
Animal Manure: Some darkling beetles are attracted to and feed on animal dung, which can serve as a source of nutrients for them.
Roots and Vegetation: While their primary diet is decaying matter, some darkling beetles may also consume plant roots and vegetation if other food sources are limited.
Algae: In certain arid environments, darkling beetles may feed on algae growing on rocks or other surfaces.
Carrion: Some darkling beetles may scavenge on carrion or dead animals, contributing to the decomposition process.

Darkling beetles play an essential role in nutrient cycling and ecosystem decomposition. Their ability to consume a wide range of organic matter contributes to the breakdown of dead and decaying material in natural ecosystems. However, in agricultural settings, certain species can be problematic pests, particularly when they infest stored food products.

What Do Stag Beetles Eat?

Stag beetles, known for their imposing mandibles and large size, have adult dietary preferences that vary slightly from those of their larvae (grubs). Here's what adult and larval stag beetles eat:

Adult Stag Beetles:

Sap: Adult stag beetles are primarily attracted to tree sap, which serves as their primary food source. They often feed on sap that oozes from wounded or decaying trees, as well as the sap flows created by other insects. They use their mandibles to scrape and consume the sap.
Ripened Fruits: Stag beetles are occasionally known to feed on ripened, sugary fruits such as overripe strawberries, peaches, and nectar from flowers.
Fermented Substances: They may be attracted to fermented materials, such as beer, wine, and fruit juices. In some regions, people have observed stag beetles visiting open beverage containers.
Tree Exudates: In addition to sap, stag beetles might consume other tree exudates like resin and gum, although sap is their primary choice.

Stag Beetle Larvae (Grubs):

Decaying Wood: The larval stage of stag beetles primarily feeds on decaying wood. They are often found in decaying logs, tree stumps, or other wood materials. Their powerful mandibles allow them to chew and digest the wood as their primary source of nutrition.
Fungi: Stag beetle larvae also consume fungi that grow on decaying wood, which can provide additional nutrients.

The dietary preferences of stag beetles can vary depending on their environment and the availability of food sources. While adult stag beetles have a more varied diet that includes sap and fruits, the larvae are specialized wood-boring insects, and their diet is limited to decaying wood and associated organisms like fungi. Stag beetles play a vital ecological role in recycling dead and decaying trees, contributing to nutrient cycling in forest ecosystems.

What Do Japanese Beetles Eat?

Japanese beetles (Popillia japonica) are known as voracious herbivores and are considered agricultural and horticultural pests due to the extensive damage they can cause to a wide range of plants. These beetles feed on various plant parts and have a broad diet. Here is a detailed overview of what Japanese beetles eat:

Leaves: Japanese beetles primarily feed on the leaves of a variety of plants. They consume the leaf tissue, leaving behind skeletonized leaves with only the veins remaining. This feeding can lead to defoliation, which can stress and damage plants.
Flowers: Japanese beetles are also known to feed on the petals and reproductive structures of flowers. Their feeding can result in flower damage and reduced pollination.
Fruits: These beetles feed on the fruit of various trees and plants. They can be particularly destructive to fruit trees and berry bushes, as their feeding can scar and damage the fruit, making it unsuitable for harvest.
Grasses: Japanese beetles will feed on the leaves of grasses, including lawn grasses. This can lead to brown patches in lawns and reduced aesthetic appeal.
Shrubs and Trees: Japanese beetles are not limited to specific plant types and can target a wide variety of ornamental shrubs and trees in gardens and landscapes.
Vegetables: In gardens, Japanese beetles may also feed on a range of vegetables, including beans, corn, tomatoes, and peppers.

Japanese beetles are a significant concern for gardeners, farmers, and horticulturists because they can cause extensive damage to a variety of plants. Integrated pest management strategies are often employed to manage and control Japanese beetle populations, which may include the use of traps, biological controls, and insecticides in some cases.

What Do Ground Beetles Eat?

Ground beetles, which belong to the family Carabidae, are a diverse group of predatory insects known for their beneficial role in controlling pest populations. They are primarily carnivorous and feed on a wide range of other small invertebrates. Here's a detailed overview of what ground beetles eat:

Insects and Other Arthropods: Ground beetles are voracious predators and primarily feed on other insects and arthropods. Their diet may include pests like caterpillars, grubs, aphids, snails, slugs, and other small invertebrates that they can capture and subdue.
Worms and Larvae: Ground beetles will also feed on earthworms and various insect larvae, such as those of beetles and moths.
Small Snails and Slugs: Some ground beetle species are known for their ability to prey on snails and slugs. They can help control populations of these garden pests.
Other Ground-Dwelling Arthropods: Ground beetles may also consume spiders and other ground-dwelling arthropods found in their habitat.
Decomposing Organic Matter: While their primary diet is focused on predation, ground beetles may occasionally feed on decomposing organic matter and detritus.
Plant Material (Occasionally): Some ground beetle species may consume small amounts of plant material, particularly when other food sources are scarce. However, this is less common, and their diet is predominantly carnivorous.

Ground beetles are considered valuable natural enemies of agricultural and garden pests. They help control pest populations and reduce the need for chemical pesticides. To attract and support ground beetles in your garden, it's important to maintain a diverse habitat with adequate ground cover, organic matter, and shelter for these beneficial insects.