The common cockchafer (Melolontha melolontha), 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 (the forest cockchafer).
The cockchafer develops via metamorphosis, in which the beetle undergoes stages of eggs, larvae, pupae and adults.
The mating behaviour is controlled by pheromones. The males usually swarm during the mating season while the females stay put and feed on leaves.
Distribution
Cockchafers are prevalent across Europe, including in Germany, France, and the United Kingdom. They are particularly prevalent in temperate regions with suitable soil conditions for larval development. However, they have also been reported in parts of Asia, including Turkey and the Caucasus region. Geographical barriers, climatic conditions, and ecological factors may limit their dispersal to other continents.
Description
Adults
thumb|Close up of a male cockchafer, showing the seven "leaves" on the antennae|277x277px
Adults of M. melolontha reach sizes of in length.
Larvae
Larvae have 3 stages of development over the course of 3–4 years. In the first stage, they are 10–20 mm long, then grow to 30–35 mm in the second year of development, and finally reach their full size of 40–46 mm in their final year of development before emerging.
Food resources
Cockchafer feeds on deciduous plant and fruit tree leaves, including oaks, maple, sweet chestnut, beech, plum, and walnut trees. The feeding behaviour of larvae can cause severe damage to the plants. They feed on both the small roots of field plants such as grain, grass, tree, beet roots and the large part of crop rootlets. Larvae can gnaw the root for 30 cm each day, which quickly kills the plant.
M. melolontha adults are predated by ground beetles and ants. Larvae are predated by click beetles while underground. Starlings, crows, and gulls also predate M. melolontha larvae, often after a field has been plowed. This behaviour occurs for several hours until darkness for about 10-20 days. GLVs have been found to act as a kairomone, which is a compound released by an organism that only benefits the receiver.
19th century
Both the grubs and adults have a voracious appetite and thus have been and sometimes continue to be a major problem in agriculture and forestry. In the pre-industrialised era, the main mechanism to control their numbers was to collect and kill the adult beetles, thereby interrupting the cycle. They were once very abundant: in 1911, more than 20 million individuals were collected in 18 km<sup>2</sup> of forest.
In Sweden the peasants looked upon the grub of the cockchafer as furnishing an unfailing prognostic whether the ensuing winter will be mild or severe; if the animal has a bluish hue (a circumstance which arises from its being replete with food), they affirm it will be mild, but if it is white, the weather will be severe: and they carry this so far as to foretell, that if the anterior be white and the posterior blue, the cold will be most severe at the beginning of the winter. Hence they call this grub Bemärkelse-mask—prognostic worm.
Modern times
Only with the modernisation of agriculture in the 20th century and the invention of chemical pesticides did it become possible to effectively combat the cockchafer. Combined with the transformation of many pastures into agricultural land, this has resulted in a decrease of the cockchafer to near-extinction in some areas in Europe in the 1970s.
Since the 1970s, agriculture has generally reduced its use of pesticides. Because of environmental and public health concerns (pesticides may enter the food chain and thus also the human body) many chemical pesticides have been phased out in the European Union and worldwide. In recent years, the cockchafer's numbers have been increasing again, causing damage to agricultural use of over of land all over Europe (0.001% of land).
Due to legal provisions from the European Union for the sustainable use of pesticides, aerial treatment, which had been used to successfully control M. melolontha populations, is now banned. Light traps have been successful in attracting M. melolontha adults, particularly males, when put at height (4 m). If a peak swarming time can be identified, shaking isolated trees and collecting feeding adults can reduce population, though it is time consuming. Pre-cropping is also a promising possibility, with buckwheat being of particular interest because it can reduce grub weight and population density before the crop of interest is planted. Entomopathogenic nematodes have been found to be particularly successful ways of reducing populations, particularly when larvae are in the first and second stage.
Intestinal components and microbiome
The gut enzymes and microbiota of M. melolontha larvae allow them to exploit a variety of ecological niches unique to their phylogenetic family. These are low energy foods such as grass roots and rotting organic matter in the soil. There are two major compartments in the scarabaeid larvae intestinal tract. The first is a tubular midgut that secretes hydrolytic enzymes for macromolecule breakdown, and the second is a bulbous hindgut used for fermentation. High bacterial diversity between individuals of M. melolontha in the intestinal tract reflects the diversity of food sources.
In the midgut, glucose is broken down and absorbed by the epithelium. It has been shown that proteolytic breakdown of toxins is a common resistance mechanism for agricultural pests. derives from the late-17th-century usage of "cock" (in the sense of expressing size or vigour) + "chafer" which simply means an insect of this type, referring to its propensity for gnawing and damaging plants.
The term "chafer" has its root in Old English ceafor or cefer, of Germanic origin and is related to the Dutch kever, all of which mean "gnawer" as it relates to the jaw. As such, the name "cockchafer" can be understood to mean "large plant-gnawing beetle" and is applicable to its history as a pest animal.
In culture
thumb|right|[[Max and Moritz shaking cockchafers from a tree]]
thumb|A group of cockchafers in Ukraine
Children since antiquity have played with cockchafers. In ancient Greece, boys caught the insect, tied a linen thread to its feet and set it free, amusing themselves to watch it fly in spirals. English boys in Victorian times played a very similar game by sticking a pin through one of its wings. Nikola Tesla recalls that as a child he made one of his first "inventions", an "engine" made by harnessing four cockchafers in this fashion.
Cockchafers appear in the fairy tales "Thumbelina" by Hans Christian Andersen and "Princess Rosette" by Madame d'Aulnoy.
The cockchafer is featured in a German children's song similar to the English "Ladybird, Ladybird":
{| class="wikitable" border="1"
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Cockchafer, fly!<br />
Father is at war,<br />
Mother is in Pomerania,<br />
Pomerania is burned to the ground –<br />
Cockchafer, fly!
|}
The verse dates back to the Thirty Years' War in the first half of the 17th century, in which Pomerania was pillaged and suffered heavily. Since World War II, it is associated in Germany with the closing months of that war as well, when Soviet troops advanced into eastern Germany.
thumb|Example of decorative trim, , which translates to 'cockchafer eyebrows'.
According to one source, the dumbledore in Thomas Hardy's 1899 poem An August Midnight is a cockchafer. However, in his novel The Mayor of Casterbridge, Hardy uses the dialect word dumbledore to mean a bumble bee.
There have been four Royal Navy ships named .
Decorative trims of women's dresses between the 1750s and 1780s, were known as , translating to 'cockchafer eyebrows'. This referred to the beetles fan-like antennae that resembled the decorative trim made with knotted silk floss.
See also
- Red-headed cockchafer, native to Australia
Explanatory notes
Citations
External links
- Der Maikäfer , from the Senckenberg Museum in Frankfurt