What Do June Bugs (June Beetles) Eat?

June bugs, also known as June beetles, are a type of scarab beetle belonging to the family Scarabaeidae. They are known for their clumsy flight and nocturnal activity. These insects are most active at night and are easily drawn toward light coming from homes and gardens in residential areas. There are approximately 300 species of June bugs in the genus Phyllophaga, distributed throughout the Americas. They most often emerge in the spring, which is why they are commonly called June beetles, and sometimes May beetles. Continue reading to discover what these insects eat and why they are considered pests to lawns, gardens, and crops, primarily due to their larvae.

June Bug: Overview

June bugs are reddish-brown beetles with a stout body, typically 0.5 to 1 inch long. They are distributed globally, though they are most common in North and South America. June bugs are clumsy fliers, often landing on their backs and struggling to flip over. Their undersides are covered with setae, tiny, stiff, hair-like bristles, which can sometimes cause them to get tangled in human hair. While this can be startling, June bugs are harmless to humans.

These insects have a multi-year life cycle in which they spend most of their time underground as white grubs that feed on roots. Adults emerge in late spring or early summer to mate and lay eggs. 

Females lay 60 to 75 eggs in the soil, usually near plant roots, during midsummer. In two to three weeks, the grubs hatch and feed on plant roots throughout the summer. When the temperature begins to drop in the fall, the grubs burrow deeper into the soil to overwinter. They continue to grow and feed for one to four years, depending on the species.

June Bug Diet

Adult June bugs are herbivores whose diet consists of leafy plants, including the leaves of many deciduous trees, such as maple, hickory, and oak, as well as the leaves of smaller plants, including strawberries and potatoes. June bug larvae, called grubs, eat the roots of grasses and other vegetation.

June bugs are a common nuisance for both gardeners and farmers, though their preferred host plants vary by species. Generally, the larvae of all species pose the greatest threat to plants and lawns.

June bug larvae can damage commercial crops as they feed on plant roots, which disrupts the plant’s ability to absorb water and nutrients, leading to lowered crop yield and, in extreme cases, death of the plants. However, significant commercial crop damage is more commonly caused by other beetle species, such as the Japanese beetle (Popillia japonica). Grubs are considered pests by many gardeners as they can damage landscaping and leave gaping spots of dead grass in lawns.

Enriching Ecosystems

Although June bug larvae can be problematic for farmers and gardeners, they still play an important role in enriching ecosystems. White grubs benefit ecosystems by recycling nutrients, decomposing organic matter, and serving as a food source for other animals. As they consume decaying plant material, they help break it down, enriching the soil and contributing to nutrient cycling.

Predators

June bugs and white grubs are good sources of protein and fat for many vertebrates. The primary predators of these insects include birds, mammals such as skunks and raccoons, and beneficial insects like ground beetles and parasitic wasps. Parasitic wasps and flies lay their eggs on or in June bugs and grubs, which serve as hosts for their larvae. The American pelecinid wasp (Pelecinus polyturator) deposits eggs on June bug larvae underground, while certain flies, like the waved light fly (Pyrgota undata), lay eggs directly on adult beetles.

Humans can also prey on June bugs. Like crickets and mealworms, June bugs are edible and safe for human consumption. Both adult June bugs and white grubs can be consumed, although June bug larvae are considered more nutritious and palatable than the adult form.