Melolontha melolontha L. - Common Cockchafer, May-bug, May Beetle

Systematic position.

Class Insecta, order Coleoptera, suborder Polyphaga, infraorder Scarabaeoidea, family Melolonthidae, subfamily Melolonthinae, tribe Melolonthini, genus Melolontha.

Biological group.

Polyphagous pest.

Morphology and biology.

Common Cockchafer is quite a large beetle 22-32 mm long with a heavy-set bulging body. Its major color is black and the elytrae, legs and antennae, as well as palpi and pygidium are light brown to dark brown and strong color polymorphism is habitual. The head is quite small, retracted into the heavy shield of prothorax, the latter covered with dense light hairs, especially on the sides. Head bears a couple of fan-like antennae, which in males are branched with seven leaf-like plates, wider and twofold bigger than in females, possessing but six plates. Brown elytrae bear four ribs. There are white triangular well distinguished spots on the sides of abdomen. The last abdominal somit is elongated into a dolabriform outlet, the pygidium, which is longer, more flat and back-driven in males. In females, it is shorter, sharper and more stuck to the body, almost perpendicularly. The tibium of the female's first leg is widened and has notches on its sides. The beetle eggs are oval, 2-3 mm in size, dirty white. Larvae are whitish yellow and C-shaped. Brown head bears tetramerous antennae and strong mandibulae. There are three pairs of legs. The abdomen consists of 10 somits, the latter two are massive. Two parallel longitudinal rows of 22-30 chaetae are present on the last somit. Larvae have three instars, distinguished by head capsule width (2.5 mm in first, 4 mm in second and 6 mm in third instar larvae). Pupa is free, colored light yellow. Young cockchafer beetles appear in soil as soon as the summer ends and hibernate there until the next spring. In sourthern regions they usually emerge from second half of April until beginning of June. In northern regions beetles emerge from middle of May to the end of June. Beetles fly in the edges of deciduous plantations and couple during additional feeding. A female bearing mature eggs repeatedly stops feeding and flies to the openings to lay eggs, each time using the same path. They prefer light warmed soils with a sparse grass covering, laying 10 to 30 eggs at the depth of 10-40 mm. They return to the feeding places about 3 times. Adults feed on the edges of forest plantations, getting as far as 50 m inside the woods and using leaves of oak, beech, maple, elm, hazel, poplar, willow, as well as fruit trees. Larvae emerge after 40-50 days, from the end of June to July. Initially they consume humus particles, then eat up small roots. In northern and middle Europe quadrennial developmental period prevails, while in warmer south regions development is triennial. The most notable damage is brought by smaller and larger root injury by second and third instar larvae from May to September.


The Common Cockchafer is distributed on the larger part of Europe (France, Belgium, Switzerland, Germany, Austria, Serbia and Montenegro, Macedonia, Albany, Bulgaria, Romania, Hungary, Slovakia, Czech Republic and Poland). It can be found also in Portugal, Spain, Italy and Greece. To the north its area reaches south of Sweden. On the east it is found in the European part of Former Soviet Union. The areal boundary leads from Estonia to Kharkov, then to Zaporozhye and Odessa; to the east to the line coming through the Estonia toward Smolensk - Kursk - Voronesh - Kharkov; south areal boundary lays through Zaporozhye - Kirovograd - north of Odessa Region - lower course of Dniestr river.


Color dimorphism is typical for adults. Although all the tints from red and brown-red to black are observed in the color of head, prothorax, scutum and legs, two varieties dominate: red beetles with red prothorax and legs (referred to as Rex) and black ones with black prothorax and legs (Nigripes). These aberrations should be considered as ecological forms of the Common Cockchafer. Red beetles prevail in open and slightly shadowed places, while black ones are more common on shadowed plots, including rarefied forest. Red beetles dominate on the north and black ones on the south. Common Cockchafer is more photo- and hygrophilic as compared to Forest Cockchafer and is more often found on the fields surrounded by forest. The young firs and pines are the most susceptible to injury and perish after being strongly damaged. Almost every Cockchafer population develops within a perennial cycle with years of prevalent flight, called degrees. In the regions were beetle populations are relatively homogenous, predominate degrees and flight years remain stable for a long time and are easy to predict. Rex beetles develop in a five year cycle while nigripes beetles develop in four. Otherwise, the mass flight of the former occurs each five years and the latter, each four. However, the mass flight occurs by a strictly determined cycle and there are three- or four-year periods when beetles are scarcely found. Natural enemies, such as moles, badgers, bats, cuckoos, woodpeckers, thrushes, magpies, rooks, jackdaws, sparrows, ground beetles, large wasps and tachinid flies notably decrease may beetle numbers. All the Common Cockchafer.s developmental stages, and especially pupae and imagoes, are submerged to infection with entomopathogenic fungi Beauveria brongniartii S. and B. bassiana B., bacteria Bacillus thuringiensis and Coccobacillus sp., microsporidia Pleistophora melolonthae H. and Telohania sp.

Economic significance.

In world agricultural practice, grubs are known as pests of many crops (plum trees, apple trees, cherry tree, berry bushes, grass plants). The third instar larvae are the most voracious, causing great damage to young trees and especially to the fruit tree farms. Beetles eat up leaves and flowers. With the density of 5 to 40 beetles per square meter, plant damage may reach 25%. To control the Cockchafers, the recommendations include stimulation growth of healthy and resistant plantings with help of soil treatment with annual or bi-annual fallowing, correct choice of tree and bush grades, the use of high quality seeding and planting material and field tillage, which causes larvae death due to mechanical injury, and birds. predation. Beetles may be caught and destroyed using light traps. Organophosphorous insecticides are applied to the plantings after blooming during the beetle flight period and to the soil to kill larvae and to treat roots before the planting. Beauveria bassiana-based mycoinsecticides show good results as well.

Reference citations:

Dmitriev, G.V. 1969. Bases for protection of green plantings from the pestiferous arthropods. Family Scarabaeidae. Kiev: Naukova dumka, p. 279, 377 (in Russian).
Gavyalis, V. 1970. Distribution of beetles of the Melolontha genus in Lithuanian SSR and its flight years // In:, V.Ya., ed. Pests of agricultural and forest plants and their control measures. Proc. 7th Baltic Conf. Plant Protection. P. 2. Elgava: Pribaltiiskii filial VIZR, p. 68-71 (in Russian).
Lavrov, M.T. 1959. Impact of wood type and associated mechanical and chemical soil composition on the distribution of Common and Forest Cockchafer in the region of its areal contact. In: Bei-Bienko, G.Ya., ed. Proc. 4th Congr. All-Union Entomol. Soc. Agricultural and forest entomology, biological pest control, apiculture and sericulture. P. 2. Moscow, Leningrad: Akademiya nauk SSSR, p. 128-131 (in Russian).
Merzeewska, E. 2001. Biological control for Melolontha melolontha grubs using a preparation of Beauveria bassiana in eastern Poland. In: Soroka, S.V., ed. Plant protection at the threshold of 21st century. Proc. Sci. Practic. Conf. devoted to 30th anniversary of BelNIIZR. Minsk: Belbiznespress, p. 465-466 (in Russian).
Mishnev, A.K., Gorbunov, A.F. 1984. Harmfulness of Common Cockchafer in Sumsk Region. In: Tsygankova, E.N., ed. Proc. 9th Congr. All-Union Entomol. Soc. P. 2. Kiev: Naukova dumka, p. 49-50 (in Russian).
Negrobov, S.O. 1960. On the fauna and ecology of stag-beetles and scarabs (Coleoptera: Lucanidae, Scarabaeidae) of Voronezh Region. Entomologicheskoe obozrenie 79 (1): 89-95 (in Russian).
Tanskii, V.I. 1985. Application of economical harmfulness thresholds of most important pests of major agricultural crops. Methodical guidelines. Leningrad: VIZR, 28 p. (in Russian).
Tsinovskii, Ya.P. 1957. Biological bases for the forecasting of scarabeid beetles pupation In: Bei-Bienko, G.Ya., ed. Proc. 3rd Congr. All-Union Entomol. Soc., Tbilisi. Moscow, Leningrad: Izdatel.stvo Akademii nauk SSSR, p. 38-39 (in Russian).
Vasil.ev, V.P., Livshits, I.Z. 1984. Fruit crop pests. Common Cockchafer (Melolontha melolontha L.). Moscow: Kolos, p. 128-129 (in Russian).
Zotsenko, L.N. 1958. Pests and diseases of fruit crops. Forecast of emergence and estimation of number of pests and diseases of agricultural crops. Moscow: Izdatel.stvo sel.skogo hozyaistva SSSR, p. 461 (in Russian).
Telnov, D. Ziemelgauja Protected nature area. Latvija N., Valka dist., V. 29. 2005.

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