June bugs, commonly known as May beetles or June beetles, are robust, reddish-brown insects about one-half to one inch long that appear during late spring or early summer evenings. These nocturnal beetles are a familiar sight, often buzzing clumsily around outdoor lights. Their seasonal appearance and disappearance often spark curiosity about their life cycle.
The June Bug Life Cycle
The life cycle of a June bug has four distinct stages: egg, larva, pupa, and adult. Female June bugs lay eggs in the soil during late spring or early summer, depositing 60 to 75 eggs, some species up to 200. These tiny, pearl-like eggs are usually placed a few inches deep in the soil near plants or organic matter.
After approximately two and a half to four weeks, eggs hatch into larvae, commonly called white grubs. This stage is spent underground, where grubs feed voraciously on plant roots and decaying organic material. This subterranean stage varies by species and environmental conditions, generally lasting one to four years, often around three years. They molt as they grow, burrowing deeper into the soil during colder winter months to survive.
Fully grown grubs enter the pupal stage, forming a protective chamber within the soil. This phase lasts about three weeks, as the insect metamorphoses into its adult form. Upon completing pupation, adult June bugs emerge from the soil, ready to mate and continue the cycle. The adult stage is brief, lasting one to two months or less, explaining their short observable presence.
Peak Activity and Seasonal Decline
Adult June bugs typically emerge from the soil in late May to early June. They are most active during warm evenings and are notably drawn to light sources, frequently swarming around outdoor lights after dusk. This peak activity period is concentrated in June, giving them their common name.
Their emergence timing is influenced by environmental factors, with warmer spring temperatures potentially triggering an earlier appearance. After their brief adult lifespan, focused on mating and laying eggs, their numbers decline. By mid to late summer, typically late August to early September, adult June bugs largely disappear as they complete their life cycle. While the adults vanish, the next generation of larvae continues to develop underground, remaining hidden until their own emergence in subsequent years.
Are June Bugs a Problem?
Adult June bugs are generally harmless to humans and pets; they do not bite or sting. For pets, consuming a few June bugs is usually not harmful or toxic. However, eating many can lead to gastrointestinal upset, such as vomiting or diarrhea, due to their hard exoskeletons. A minor risk exists if bugs have been exposed to pesticides.
While adult June bugs feed on the leaves of trees and shrubs, they typically do not cause significant damage unless present in very large numbers. The primary concern lies with their larval stage, the white grubs. These grubs feed extensively on the roots of grasses and other plants, leading to damage in lawns and gardens. Signs of grub damage include brown or dead patches of grass that can be easily pulled back, and a spongy feel to the lawn. Grubs also attract animals like skunks, raccoons, and birds, which dig up lawns searching for food, causing additional damage.