Common cockchafer

The common cockchafer, also colloquially known as the Maybug, Maybeetle, or doodlebug, is a species of scarab beetle belonging to the genus Melolontha. It is native to Europe, and it is one of several closely-related and morphologically similar species of Melolontha called cockchafers, alongside Melolontha hippocastani .

Cockchafers are primarily crepuscular and nocturnal, with adults becoming active at dusk. They exhibit positive phototaxis, often flying toward lights in large numbers. Feeding occurs on the leaves of deciduous trees, with adults using their strong mandibles to chew foliage, sometimes resulting in visible damage to host plants. Larvae are subterranean and feed on the roots of grasses and crops, making them significant agricultural pests. Adults are solitary outside of the breeding season but may form temporary aggregations during mating flights, especially in warm, calm weather. Flight activity peaks in late spring, with individuals often flying clumsily and producing a characteristic buzzing sound. Defensive behaviors include feigning death (thanatosis) and releasing a foul-smelling fluid from abdominal glands when threatened.

Mating occurs shortly after adult emergence, typically in May and June. Males locate females through pheromonal cues detected by their enlarged antennae. After copulation, females burrow into loose, sandy or loamy soil to lay eggs, depositing 20–30 eggs per clutch and up to 80 eggs in total over several weeks. The eggs hatch after 4–6 weeks, and the larvae (white grubs) begin feeding on plant roots. Larval development lasts 3–5 years, depending on temperature and food availability, with three distinct instars. Pupation occurs in an earthen chamber at a depth of 20–40 cm, lasting 4–6 weeks. Adults overwinter underground and emerge the following spring. There is no parental care; all developmental stages are independent after egg-laying.

The cockchafer's lamellate antennae are highly specialized for detecting sex pheromones, facilitating mate location over long distances. Larvae possess robust mandibles and a strong, curved body adapted for burrowing and feeding on tough plant roots. The adult's cryptic coloration and tufts of white hair provide camouflage among leaf litter. Their synchronized emergence in large numbers is an evolutionary strategy to overwhelm predators (predator satiation). Adults can feign death and emit deterrent chemicals to avoid predation. The extended larval stage allows exploitation of stable underground food resources and reduces exposure to above-ground threats.

The cockchafer has played a prominent role in European folklore and culture, often symbolizing the arrival of spring. In the 19th and early 20th centuries, swarms were so abundant that children collected them for games, and they featured in songs and nursery rhymes. The beetle is referenced in literature, such as Goethe's works, and was once used as a food source for poultry or even as a novelty snack. Its periodic outbreaks have made it both a symbol of agricultural hardship and natural abundance. In some regions, the cockchafer was believed to predict weather or harvest outcomes.

Recent research has focused on the cockchafer's pheromone communication, with identification of key volatile compounds mediating mate attraction. Studies on larval gut microbiota have revealed symbiotic bacteria aiding in cellulose digestion. Integrated pest management (IPM) strategies are under development, including biological control with entomopathogenic nematodes and fungi. Genomic studies are ongoing to elucidate genes involved in detoxification and resistance to pesticides. Long-term monitoring projects track population dynamics in response to climate change and land use. There is also renewed interest in the ecological role of cockchafers as prey for birds and mammals.

Sources

The Common cockchafer is currently classified as Least Concern on the IUCN Red List.

Historically, cockchafer populations experienced dramatic fluctuations, with outbreaks causing severe agricultural damage in Europe. Intensive pesticide use in the mid-20th century led to drastic declines, but populations have partially recovered following pesticide restrictions. Current threats include habitat loss due to agricultural intensification, soil compaction, and continued use of soil insecticides. Natural predators (birds, mammals, parasitic wasps, and nematodes) and fungal pathogens also regulate populations. Climate change may alter emergence timing and larval development rates. The species is currently listed as Least Concern, but local outbreaks and declines are closely monitored due to its pest status.