Melolontha melolonthacommon European cockchafer(Also: maybug)

Geographic Range

Also known as the June bug or May bug, the common cockchafer is found throughout temperate Europe and the continental United States. (Arnett, 1985; Fraval, 1998)


Common cockchafers typically live in areas with soft, shaded soil. The cockchafer is frequently found on agricultural land. (Fraval, 1998)

Physical Description

Adult cockchafers typically range from 25 to 30mm. Adult Melolontha melolontha have a dark head with a shiny black pronotum covered by short, closely set hairs. They also have a dull black abdomen and a long, flat pygidium. Eyes are multifaceted, with 5,475 facets per eye, providing very acute vision. Males have longer antennae than females, with a large, fan-like club protruding from each terminus. New wing cases are typically mottled with a white powder. Immature (larval) common cockchafers reach lengths of about 40 to 46mm, and have a dull white body colored black at the abdomenal extremity. Cockchafer grubs curve into an arc and have a large head with strong, grabbing mandibles. In overall appearance grubs are fleshy, elongated, and slightly hairy. (Burton, 1979; Fraval, 1998; Pesson, 1959)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    25 to 30 mm
    0.98 to 1.18 in


Early larval development takes approximately 4 to 6 weeks. Larvae slow development over the winter, and in mid-April they suddenly spring back to activity and eat until October. They then hibernate until the third year, when they resume feeding in July and become fully mature in August. However, the fully mature adults do not become active until the following spring, giving the cockchafer a lengthy life cycle. (Blum, 1985; Fraval, 1998)


The reproductive cycle of the cockchafer is lengthy and triggered by a combination of hormones and environment. Environmental factors, such as the time of day and season trigger endocrines in females. Females in turn send out powerful pheromones, which males detect with their large antennae. Mating occurs typically in late May and early June. Females deposit eggs in a path opposite to that of the pre-mating flight. (Blum, 1985; Fraval, 1998)

After copulation, eggs are deposited about 20 at a time in soft soil. (Blum, 1985; Fraval, 1998)

  • Average age at sexual or reproductive maturity (male)
    3 years


Cockchafers' buzzing and squeaking around trees at dusk, and around lights at night are a common sound and sight on spring nights. Some cockchafers infest a single tree while others fly around an entire forest roaming for food. They can be often be found buzzing around house lights. (Burton, 1979; Fraval, 1998)

Food Habits

In April and May, adult cockchafers fly singly in search of food. Melolontha melolontha ear deciduous tree and fruit tree leaves, particularly oaks, maple, sweet chestnut, beech, plum, and walnut trees. While adults are considered harmful only in large populations, the eating habits of larvae cause far more damage to crops. Larvae gnaw at small roots of field plants, and are indiscriminate feeders; they eat grain, grass, tree, and beet roots, moving as much as 30 cm a day while eating large sections of crop rootlets. Cockchafer larvae feed on new, fresh soil roots and do not usually eat decaying organic matter. (Fraval, 1998)

  • Plant Foods
  • leaves
  • roots and tubers

Economic Importance for Humans: Positive

No positive human benefit has yet been attributed to the common cockchafer.

Economic Importance for Humans: Negative

Adults generally only cause damage when they are found in extremely large populations. Larvae, however, are reviled in gardens and farms everywhere they inhabit. This is because the larvae gorge themselves for over 3 years on the fresh rootlets of plants and trees. This can wipe out crops and weaken older trees. (Fraval, 1998)

  • Negative Impacts
  • crop pest

Conservation Status

This animal requires no special status.

Other Comments

Juvenile larvae feed on parental excrement in order to ingest a certain symbiotic intestinal bacteria. The bacteria then live within the larval gut and help digest cellulose fibers from rootlets. (Arnett, 1985; Fraval, 1998)


Sara Diamond (editor), Animal Diversity Web.

Jared Cardiff (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map


living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map


living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


active at dawn and dusk


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


union of egg and spermatozoan


an animal that mainly eats leaves.


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


An animal that eats mainly plants or parts of plants.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.


the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

internal fertilization

fertilization takes place within the female's body


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season


reproduction that includes combining the genetic contribution of two individuals, a male and a female


living in residential areas on the outskirts of large cities or towns.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.


A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.


Arnett, R. 1985. American Insects. New York: Van Nostrand Reinhold.

Blum, M. 1985. Fundamentals of Insect Physiology. New York: John Wiley and Sons.

Burton, J. 1979. The Oxford Book of Insects. New York: Oxford University Press.

Fraval, A. 1998. "HYPP Zoology" (On-line). Accessed April 15, 2001 at

Pesson, P. 1959. The World of Insects. New York: McGraw-Hill.