Editing Cockchafer

{{Short description|Species of scarab beetle}}
{{other uses}}
{{Speciesbox
| name = Common cockchafer
| image = Hanneton commun (Melolontha melolontha) ♀, Parc de Woluwé, Bruxelles (51222810874).jpg
| image_caption = Female
| genus = Melolontha
| species = melolontha
| authority = Linnaeus, 1758
}}
The '''common cockchafer''' (''Melolontha melolontha''), also colloquially known as the '''Maybug''',<ref name=BugLife/>{{efn|Other names include: bracken clock, bummler, chovy, cob-worm, dorrs, dumbledarey, dumbledore, humbuz, June bug, kittywitch, billy witch, may-bittle, midsummer dor, mitchamador, oak-wib, rookworm, snartlegog, spang beetle, tom beedel and {{lang|cy|chwilen y bwm}} ([[Welsh language|Welsh]]).<ref name=BugLife>{{cite web|title=Common Cockchafer|url=https://www.buglife.org.uk/bugs-and-habitats/common-cockchafer|publisher=Bug Life}}</ref><ref name=BB>{{cite book |author1=Marren, Peter |author2=Mabey, Richard |title=Bugs Britannica |url=https://books.google.com/books?id=Ah62bUZLDOwC |year=2010 |publisher=Chatto & Windus |isbn=978-0-7011-8180-2}}</ref>}} '''Maybeetle''',<ref>{{Cite web|title=Cockchafer {{!}} insect|url=https://www.britannica.com/animal/cockchafer|access-date=2021-07-01|website=Encyclopedia Britannica|language=en}}</ref> or '''doodlebug''',<ref name="DiscWlife">{{cite web |title=7 things you never knew about the cockchafer |publisher=Discover Wildlife |url=http://www.discoverwildlife.com/animals/7-things-you-never-knew-about-cockchafer |date=8 April 2014 |access-date=4 July 2016}}</ref> 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.<ref name=":0" /> The leaves release green leaf volatiles when they are fed on by females, which the male can sense and thus locate the female for mating opportunity.<ref name=":2" /><ref name=":3" /> The larvae use both the plant volatiles and CO<sub>2</sub> to locate the plant root for food.<ref name=":1" />

This species is an important and nutritious food source for many species. The adults and larvae feed on plants, and are regarded as [[agricultural pests]] of crops such as grasses and fruit trees. Adults have harmful effects for the crop when they aggregate in large groups. The larvae can cause severe damage and kill the plant by gnawing the plant roots.<ref name=":11">{{Cite web |last=Fraval |first=A. |date=1998 |title=HYPP Zoology |url=http://www.inra.fr/Internet/Produits/HYPPZ/RAVAGEUR/6melmel.htm.}}</ref>

== 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.<ref>{{Cite web |title=''Melolontha melolontha'' (Linnaeus, 1758) |url=https://www.gbif.org/species/4990995 |access-date=2024-03-21 |website=www.gbif.org |language=en}}</ref>

== Description ==

=== Adults ===
[[File:Cockchafer.JPG|thumb|Close up of a male cockchafer, showing the seven "leaves" on the antennae|277x277px]]
[[Imago|Adults]] of ''M. melolontha'' reach sizes of {{convert|25|to|30|mm|in|frac=4|abbr=off}} in length.<ref name=":0" /> Behind their heads they have a black [[pronotum]] covered with short hairs. This black coloration distinguishes them from their close relative ''M. hippocastani'', whose pronotum is brown. The top of their bodies have hard, brown [[Elytron|elytra]] and a black [[Thorax (arthropod anatomy)|thorax]], while their underside is black and partly white on the sides. They have a dark head with two antennae with ten segments each. Male cockchafers have seven "leaves" on their [[Antenna (biology)|antennae]], whereas the females have only six.<ref name=":0">{{citation |author=Huiting, H. F., Moraal, L. G., Griepink, F. C., & Ester, A. |year=2006 |title=Biology, control and luring of the cockchafer, ''Melolontha melolontha'': literature report on biology, life cycle and pest incidence, current control possibilities and pheromones |publisher=Praktijkonderzoek Plant & Omgeving |url=https://edepot.wur.nl/121073}}</ref>

=== Larvae ===

[[Larva|Larvae]] have 3 stages of development over the course of 3–4 years. In the first stage, they are 10–20&nbsp;mm long, then grow to 30–35&nbsp;mm in the second year of development, and finally reach their full size of 40–46&nbsp;mm in their final year of development before emerging.<ref name=":0" /> In some areas of Eastern Europe the larvae develop for a fourth year. They have white bodies that curve into an arc with a black coloration at the abdomen and long, hairy, and well developed legs.<ref name=":0" /> They have large orange heads with strong, grabbing [[Mandible (insect mouthpart)|mandibles]]. On their heads they have 2 small antennae which they use to smell and taste their surroundings while underground.<ref name=":1">{{Cite journal |last1=Eilers |first1=Elisabeth J. |last2=Talarico |first2=Giovanni |last3=Hansson |first3=Bill S. |last4=Hilker |first4=Monika |last5=Reinecke |first5=Andreas |date=2012-07-25 |title=Sensing the Underground – Ultrastructure and Function of Sensory Organs in Root-Feeding ''Melolontha melolontha'' (Coleoptera: Scarabaeinae) Larvae |journal=PLOS ONE |language=en |volume=7 |issue=7 |pages=e41357 |doi=10.1371/journal.pone.0041357 |doi-access=free |issn=1932-6203 |pmc=3405142 |pmid=22848471|bibcode=2012PLoSO...741357E }}</ref>

== 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&nbsp;cm each day, which quickly kills the plant.<ref name=":11" />

==Life cycle==
[[File:Feldmaikäfer (Melolontha melolontha) w 3.jpg|thumb|left|Female ''M. melolontha'' Beetle.|292x292px]]
Adults appear at the end of April or in May and live for about five to seven weeks. After about two weeks, the female begins laying eggs, which she buries about 10 to 20 cm deep in the earth. She may do this several times until she has laid between 60 and 80 eggs. Most typically, the female beetle lays its eggs in fields. The preferred food for adults is [[oak]] leaves, but they will also feed on [[conifer]] needles.

The [[larva]]e, known as "chafer grubs" or "[[white grub]]s", hatch four to six weeks after being laid as eggs. They feed on plant roots, for instance [[potato]] roots. The grubs develop in the earth for three to four years, in colder climates even five years, and grow continually to a size of about 4–5&nbsp;cm, before they [[pupa]]te in early autumn and develop into an adult cockchafer in six weeks.<ref name=":0" />

The cockchafer [[overwinters]] in the earth at depths between 20 and 100&nbsp;cm. They work their way to the surface only in spring.

Because of their long development time as larvae, cockchafers appear in a cycle of every three or four years; the years vary from region to region. There is a larger cycle of around 30 years superimposed, in which they occur (or rather, used to occur) in unusually high numbers (10,000s).

== Enemies ==

=== Predators ===
The [[European mole]] is a natural predator of cockchafers. Moles are known to feed on cockchafer larvae. They can detect them using their keen sense of smell and specialised digging behaviour. This predation can help regulate cockchafer populations in mole-inhabited areas. ''<ref name=":10">{{Cite web |last=Marzena |first=Niemczyk |date=June 2017 |title=Effect of environmental factors on occurrence of cockchafers (''Melolontha'' spp.) in forest stands |url=https://www.researchgate.net/publication/317719403}}</ref>''

''M. melolontha'' adults are predated by ground beetles and ants. Larvae are predated by click beetles while underground. [[Starling]]s, [[crow]]s, and [[gull]]s also predate ''M. melolontha'' larvae, often after a field has been plowed.<ref name=":0" />

=== Parasites ===
''Dexia rustica'' is a parasitic fly that uses ''M. melolontha'' larvae as their hosts. ''D. rustica'' eggs hatch underground and look for cockchafer larvae to hibernate within over the winter. Their presence will ultimately kill the beetle larvae in the spring. One to six fly larva can parasitise a single host.<ref name=":0" />

== Behaviour ==

=== Mating behaviour ===
[[File:Maikaefer-kalt.jpg|thumb|Male ''M. melolontha'' Beetle.|302x302px]]
Males leave the soil when the temperature is favourable in April or May. [[Sexual dimorphism]] is observed as male beetles, at dusk, will begin to [[Swarming|swarm]] and locate around groups of trees at forest edges.<ref name=":0" /> On the other hand, females will stay in place and feed on leaves until they reach sexual maturity.  Males primarily fly around the branches looking for females to mate with.<ref name=":2">{{Cite journal |last1=Reinecke |first1=Andreas |last2=Ruther |first2=Joachim |last3=Tolasch |first3=Till |last4=Francke |first4=Wittko |last5=Hilker |first5=Monika |date=2002-06-01 |title=Alcoholism in cockchafers: orientation of male ''Melolontha melolontha'' towards green leaf alcohols |url=http://link.springer.com/10.1007/s00114-002-0314-2 |journal=Naturwissenschaften |volume=89 |issue=6 |pages=265–269 |doi=10.1007/s00114-002-0314-2 |pmid=12146792 |bibcode=2002NW.....89..265R |s2cid=25772038 |issn=0028-1042|url-access=subscription }}</ref><ref name=":3">{{Cite journal |last1=Reinecke |first1=Andreas |last2=Ruther |first2=Joachim |last3=Hilker |first3=Monika |date=April 2005 |title=Electrophysiological and behavioural responses of ''Melolontha melolontha'' to saturated and unsaturated aliphatic alcohols |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1570-7458.2005.00274.x |journal=Entomologia Experimentalis et Applicata |language=en |volume=115 |issue=1 |pages=33–40 |doi=10.1111/j.1570-7458.2005.00274.x |bibcode=2005EEApp.115...33R |s2cid=84471627 |issn=0013-8703|url-access=subscription }}</ref> This behaviour occurs for several hours until darkness for about 10-20 days.<ref name=":0" /> These swarms typically have minimal damage to the trees, but they are occasionally harmful in cherry or plum orchards because of their consumption of blossoms. Once the females have matured and mated, they return to the fields to lay their eggs in the soil. Only a third of females will survive this trip, but any survivors will make a second, and occasionally third, swarming trip and return to the field to lay eggs again.<ref name=":0" />

Green leaf volatiles (GLVs) are a series of saturated and monounsaturated six-carbon [[Aldehyde|aldehydes]], [[Alcohol (chemistry)|alcohols]], and [[Ester|esters]] released by vascular plants in response to stresses.<ref>{{Cite journal |last1=Matsui |first1=Kenji |last2=Engelberth |first2=Jurgen |date=2022-10-31 |title=Green Leaf Volatiles—The Forefront of Plant Responses Against Biotic Attack |url=https://academic.oup.com/pcp/article/63/10/1378/6658151 |journal=Plant and Cell Physiology |language=en |volume=63 |issue=10 |pages=1378–1390 |doi=10.1093/pcp/pcac117 |pmid=35934892 |issn=0032-0781|url-access=subscription }}</ref> GLVs have been found to act as a [[kairomone]], which is a compound released by an organism that only benefits the receiver.<ref name=":2" /><ref name=":3" /> This enhances the attractiveness of [[toluquinone]], a [[sex pheromone]] in scarab beetles. Only male ''M. melolontha'' are attracted to GLVs, using its release to identify leaves that female beetles are feeding on. Females have the ability to detect GLV, but any change in behaviour that it may cause is unclear.<ref name=":2" /><ref name=":3" /> ''M. melolontha'' males are more sensitive to lower GLV concentrations, possibly due to the anatomical differences between male and female antennae.<ref name=":3" /> Due to this phenomenon, sexual dimorphism can be observed in flight behaviour. During swarming behaviour, males will hover around the foliage while females remain on twigs and branches to feed. Males then use GLVs to identify which leaves have females that they can mate with.<ref name=":3" /> GLVs are being investigated as a possible pest control technique to attract males and prevent mating.<ref name=":0" />

=== Pest behaviour ===
Though adults can damage some fruit trees, ''M. melolontha'' larvae are the primary agricultural pests.<ref name=":0" /> Larva hatch from their eggs 4–6 weeks after being laid and develop into adults over the course of 3–4 years. Immediately after hatching, larvae will gnaw on small roots. It will continue feeding on roots, particularly grasses, cereals, and other crops, during its three larval stages, only pausing to burrow deep into the soil for winter hibernation.<ref name=":0" />

In their first stage, ''M. melolontha'' larvae identify roots by CO<sub>2</sub> release. They will only do damage at extreme densities.<ref name=":0" /> In their second stage, larva will cause the most damage to crops.<ref name=":1" /> In their third stage, larva will do less but still severe damage to crops. They most prominently use structures on their antennae called pore plates to smell. This structure is a thin layer of cells that covers a number of sensory units consisting of [[dendrite]] bundles. These and other [[Sense of smell|olfactory]] organs on the head of the larva can identify CO<sub>2</sub> and [[Volatile organic compound|plant volatiles]]. They've also been found to push their heads into the walls of their burrows and probe with their antennae, likely to taste the soil with bristle-like [[Sensillum|sensilla]].<ref name=":1" />

==Pest control and history==
[[File:Melolontha melolontha, meikever (12).jpg|thumb|[[Larva]] (grub)]]

=== Middle Ages ===
In the [[Middle Ages]], [[pest control]] was rare, and people had no effective means to protect their harvest. This gave rise to events that seem bizarre from a modern perspective. In 1320, for instance, cockchafers were brought to [[court]] in [[Avignon]] and sentenced to withdraw within three days onto a specially designated area, otherwise they would be outlawed. Subsequently, since they failed to comply, they were collected and killed. Similar [[animal trial]]s also occurred for many other animals in the Middle Ages.<ref name="barton2">Barton, K.: ''[http://lichtenberg-gesellschaft.de/pdf/jb04_barton.pdf Verfluchte Kreaturen: Lichtenbergs "Proben seltsamen Aberglaubens" und die Logik der Hexen- und Insektenverfolgung im "Malleus Maleficarum"]'', in Joost, U.; Neumann, A. (eds): ''Lichtenberg-Jahrbuch 2004'', p.&nbsp;11ff, Saarbrücken 2004 (SDV Saarländische Druckerei und Verlag), {{ISBN|3-930843-87-0}}. In German.</ref>

=== 19th century ===
Both the grubs and [[imago|adults]] have a voracious appetite and thus have been and sometimes continue to be a major problem in [[agriculture]] and [[forestry]]. In the pre-[[Industrialisation|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&nbsp;km<sup>2</sup> of forest.<ref name="BugLife"/> Collecting adults was an only moderately successful method.

In some areas and times, cockchafers were served [[insects as food|as food]]. A 19th-century recipe from [[France]] for [[cockchafer soup]] reads: "roast one [[Pound (mass)|pound]] of cockchafers without wings and legs in sizzling [[butter]], then cook them in a [[chicken]] soup, add some [[veal]] liver and serve with [[chives]] on a [[Toast (food)|toast]]". A [[Germany|German]] newspaper from [[Fulda]] from the 1920s tells of students eating [[sugar]]-coated cockchafers. Cockchafer larvae can also be fried or cooked over open flames, although they require some preparation by soaking in vinegar in order to purge them of soil in their digestive tracts.<ref>[http://www.bugsfeed.com/cooking_cockchafer Cooking cockchafer with old-timey Europeans] 11 February 2016 ''www.bugsfeed.com'' accessed 30 May 2021</ref> A cockchafer stew is referred to in [[W. G. Sebald]]'s novel ''[[The Emigrants (German novel)|The Emigrants]]''.

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.<ref>De Geer, iv. 275–6. Kirb. and Sp. Introd., i. 33.</ref>

=== 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 [[natural environment|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 {{convert|1000|km2|sqmi|sigfig=1}} of land all over Europe (0.001% of land).

Due to legal provisions from the European Union for the sustainable use of pesticides, [[Aerial application|aerial treatment]], which had been used to successfully control ''M. melolontha'' populations, is now banned.<ref name=":4">{{Cite journal |last1=Malusá |first1=Eligio |last2=Tartanus |first2=Małgorzata |last3=Furmanczyk |first3=Ewa M. |last4=Łabanowska |first4=Barbara H. |date=2020-12-01 |title=Holistic approach to control ''Melolontha'' spp. in organic strawberry plantations |journal=Organic Agriculture |language=en |volume=10 |issue=1 |pages=13–22 |bibcode=2020OrgAg..10S..13M |doi=10.1007/s13165-020-00295-2 |issn=1879-4246|doi-access=free }}</ref> 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.<ref name=":4" /> [[Azadirachtin]] is a chemical that inhibits maturation feeding and egg development, but low persistence and difficulty spraying it high enough in trees prevents widespread use.<ref name=":4" /> [[Tillage|Soil tilling]] has been a historically successful method, particularly in early June when larvae are first hatching.<ref name=":5">{{Cite journal |last=Woreta |first=Danuta |date=2015-03-01 |title=Control of cockchafer ''Melolontha'' spp. grubs – a review of methods |url=https://www.sciendo.com/article/10.1515/ffp-2015-0005 |journal=Folia Forestalia Polonica |language=en |volume=57 |issue=1 |pages=33–41 |doi=10.1515/ffp-2015-0005 |issn=2199-5907}}</ref> [[Crop rotation|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.<ref name=":4" /> Sex pheromones have been used for mass trapping, mating disruption, and “Attract and Kill” methods. The unlikelihood of developing resistance due to the sex pheromones being produced by the beetles makes this a promising method of pest control.<ref name=":0" />

==== Entomopathogens ====
Entomopathogenic organisms—organisms that produce disease in insects—are an active area of research for the control of ''M. melolontha'' grub populations.<ref name=":9" /> [[Entomopathogenic fungi]] is currently being studied as a way to control ''M. melolontha'' grub populations. ''Beauveria brongniartii'' has been found to work on the ''Melolontha'' species, and ''B. bassiana'' has been successful with other agricultural pests. There have been difficulties with determining the best strategy to apply the fungi to the fields.<ref name=":9">{{Cite journal |last1=Tartanus |first1=Malgorzata |last2=Furmanczyk |first2=Ewa M. |last3=Canfora |first3=Loredana |last4=Pinzari |first4=Flavia |last5=Tkaczuk |first5=Cezary |last6=Majchrowska-Safaryan |first6=Anna |last7=Malusá |first7=Eligio |date=February 2021 |title=Biocontrol of ''Melolontha'' spp. Grubs in Organic Strawberry Plantations by Entomopathogenic Fungi as Affected by Environmental and Metabolic Factors and the Interaction with Soil Microbial Biodiversity |journal=Insects |language=en |volume=12 |issue=2 |pages=127 |doi=10.3390/insects12020127 |doi-access=free |issn=2075-4450 |pmc=7912822 |pmid=33540558}}</ref> [[Entomopathogenic nematode]]s have been found to be particularly successful ways of reducing populations, particularly when larvae are in the first and second stage.<ref name=":5" /> [[Entomopathogenic bacterium|entomopathogenic bacteria]] from the genera ''Steinernema'' and ''Heterorhabditis'' are also being investigated, but they have been difficult to apply to fields as opposed to laboratory settings.<ref name=":6" /> The focus on entomopathogenic bacteria has been on their symbiosis with entomopathogenic nematodes and their ability to act together as a larval control strategy.<ref name=":5" /> Poor results with the application of these methods have stemmed intensive research into the gut enzymes and microbiome of ''M. melolontha'' to determine if they are acting as defense against entomopathogenic organisms.<ref name=":6">{{Cite journal |last1=Wagner |first1=Wolfgang |last2=Möhrlen |first2=Frank |last3=Schnetter |first3=Wolfgang |date=July 2002 |title=Characterization of the proteolytic enzymes in the midgut of the European Cockchafer, ''Melolontha melolontha'' (Coleoptera: Scarabaeidae) |url=https://linkinghub.elsevier.com/retrieve/pii/S0965174801001679 |journal=Insect Biochemistry and Molecular Biology |language=en |volume=32 |issue=7 |pages=803–814 |doi=10.1016/S0965-1748(01)00167-9|pmid=12044497 |url-access=subscription }}</ref>

== 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 [[Phylogenetics|phylogenetic]] family. These are low energy foods such as grass roots and rotting organic matter in the soil.<ref name=":7">{{Cite journal |last1=Skowronek |first1=Marcin |last2=Sajnaga |first2=Ewa |last3=Pleszczyńska |first3=Małgorzata |last4=Kazimierczak |first4=Waldemar |last5=Lis |first5=Magdalena |last6=Wiater |first6=Adrian |date=2020-01-16 |title=Bacteria from the Midgut of Common Cockchafer (''Melolontha melolontha'' L.) Larvae Exhibiting Antagonistic Activity Against Bacterial Symbionts of Entomopathogenic Nematodes: Isolation and Molecular Identification |journal=International Journal of Molecular Sciences |language=en |volume=21 |issue=2 |pages=580 |doi=10.3390/ijms21020580 |doi-access=free |issn=1422-0067 |pmc=7013910 |pmid=31963214}}</ref> There are two major compartments in the [[Scarabaeidae|scarabaeid]] larvae intestinal tract. The first is a tubular midgut that secretes [[Hydrolysis|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.<ref name=":8">{{Cite journal |last1=Egert |first1=Markus |last2=Stingl |first2=Ulrich |last3=Dyhrberg Bruun |first3=Lars |last4=Pommerenke |first4=Bianca |last5=Brune |first5=Andreas |last6=Friedrich |first6=Michael W. |date=August 2005 |title=Structure and Topology of Microbial Communities in the Major Gut Compartments of ''Melolontha melolontha'' Larvae (Coleoptera: Scarabaeidae) |journal=Applied and Environmental Microbiology |language=en |volume=71 |issue=8 |pages=4556–4566 |doi=10.1128/AEM.71.8.4556-4566.2005 |issn=0099-2240 |pmc=1183286 |pmid=16085849|bibcode=2005ApEnM..71.4556E }}</ref>

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.<ref name=":6" /> [[Proteolysis|Proteolytic]] activity of enzymes in the midgut is hypothesised to increase resistance to entomopathogenic bacteria in the beetle larvae. [[Trypsin]]-like enzymes from the midgut of ''M. melolontha'' have been found to break down certain bacterial toxins and inactivate them.<ref name=":6" />

The hindgut has a high density of bacteria that ferment [[Recalcitrant seed|recalcitrant]] residues such as [[cellulose]], with the byproducts being absorbed by the beetle.<ref name=":8" /> [[Acetate]] is a major product of this fermentation, suggesting that much of the bacteria in the hindgut is [[Homo-acetogen|homoacetogenic]]. High abundance of species in the bacterial genus ''[[Desulfovibrio]]'' in the hindgut suggests that sulphate reduction is an important process, but the source of this sulphate in the diet is unknown.<ref name=":8" />

Some research on the ''M. melolontha'' microbiome has been focused on increasing the entomopathogenic properties of nematodes used as pest control due to their symbiosis.<ref name=":7" /> Bacteria such as ''Xenorhabdus nematophila'' are transported by nematodes and released into the insect's midgut. The bacteria will release [[Lysis|lytic]] enzymes and other antimicrobial substances to decrease competition from the beetle's native microbiome. This creates an optimal environment for nematode development. Bacterial species in the midgut of ''M. melolontha'' such as ''Pseudomonas chlororaphis'' have been found to fight back, acting as antagonists to entomopathogenic bacteria. These bacteria have been identified differentially in different larval stages, with ''P. chlororaphis'' usually being found in the third and final larval stage.<ref name=":7" />

== Ecological impact ==
Environmental factors such as temperature, humidity, and plant type have a considerable impact on the existence and behaviour of cockchafers in wooded environments. It indicates that cockchafer populations are strongly influenced by climatic conditions, with warmer temperatures and higher humidity level favouring their occurrence. Additionally, specific vegetation types, including deciduous trees and shrubs, provide suitable habitats for cockchafers, facilitating their survival and reproduction within forest stands. <ref name=":10" />

==Etymology==
The name "cockchafer"<ref>[https://www.etymonline.com/word/cockchafer cockchafer (n.)] ''www.etymonline.com'' accessed 30 May 2021</ref> derives from the late-17th-century usage of "cock"<ref>[https://www.etymonline.com/word/cock?ref=etymonline_crossreference#etymonline_v_15750 cock (n.1)] ''www.etymonline.com'' accessed 30 May 2021</ref> (in the sense of expressing size or vigour) + "chafer"<ref>[https://www.etymonline.com/word/chafer chafer (n.)] ''www.etymonline.com'' accessed 30 May 2021</ref> 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==
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 era|Victorian]] times played a very similar game by sticking a pin through one of its wings.<ref>{{cite news |title=Peter Parley's annual: A Christmas and New Year's present for young people |url=https://books.google.com/books?id=zSIGAAAAQAAJ |date=1866 |access-date=2017-05-27 |last=Martin |first=William }}</ref> [[Nikola Tesla]] recalls that as a child he made one of his first "inventions", an "[[engine]]" made by harnessing four cockchafers in this fashion.<ref>{{cite news |title=My Inventions |first=Nikola |last=Tesla |authorlink=Nikola Tesla |url=https://en.wikisource.org/wiki/My_Inventions |newspaper=Electrical Experimenter |date=1919 |access-date=2023-03-29 }}--</ref>

Cockchafers appear in the fairy tales "[[Thumbelina]]" by [[Hans Christian Andersen]] and "[[Princess Rosette]]" by [[Madame d'Aulnoy]].

[[File:Max und Moritz (Busch) 051.png|thumb|right|''[[Max and Moritz]]'' shaking cockchafers from a tree]]

The cockchafer is featured in a German children's song similar to the English ''[[Ladybird, Ladybird]]'':
{| class="wikitable" border="1"
|-
|
{{lang|de|{{linktext|Maikäfer}}, flieg!<br>
Der Vater ist im Krieg,<br>
die Mutter ist in Pommerland,<br>
Pommerland ist abgebrannt –<br>
Maikäfer flieg!}}
|
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.

According to one source, the dumbledore in [[Thomas Hardy]]'s 1899 poem ''An August Midnight''<ref>''Collected poems of Thomas Hardy'', 1923, p[https://archive.org/details/collectedpoemsof00hard/page/134/mode/2up 154]</ref> is a cockchafer.<ref>Brown, Joanna Cullen, Review of Thomas Hardy: Cent Poèmes. Anthologie bilingue (Les Editions de L’Aire, Vevey, 2008) by Eric Christen, Françoise Baud, The Hardy Society Journal, Vol. 4, No. 3 (Autumn 2008), pp. [https://www.jstor.org/stable/48561596 87]</ref> However, in his novel ''[[The Mayor of Casterbridge]]'', Hardy uses the dialect word dumbledore to mean a bumble bee.<ref>{{cite web | url=https://www.johndcook.com/blog/2011/09/22/thomas-hardy-and-harry-potter | title=Thomas Hardy and Harry Potter | work=www.johndcook.com | date=22 September 2011 | accessdate=30 May 2024 | author=Cook, John D.}}</ref>

[[File:Первомайське урочище Хрущі 07.jpg|thumb|A group of cockchafers in Ukraine]]

There have been four [[Royal Navy]] ships named {{HMS|Cockchafer}}.

==See also==
* [[Red-headed cockchafer]], native to Australia

== Explanatory notes ==
{{Reflist|group=lower-alpha}}

== Citations ==
{{Reflist|30em}}

==External links==
{{Commons}}
{{Wikispecies|Melolontha melolontha|Cockchafer}}
* [http://www.senckenberg.uni-frankfurt.de/expo/9805.htm Der Maikäfer] {{Webarchive|url=https://web.archive.org/web/20040609044921/http://www.senckenberg.uni-frankfurt.de/expo/9805.htm |date=2004-06-09 }}, from the [[Senckenberg Museum]] in [[Frankfurt]] {{in lang|de}}

{{Taxonbar|from=Q28175}}

[[Category:Beetles described in 1758]]
[[Category:Taxa named by Carl Linnaeus]]
[[Category:Beetles of Europe]]
[[Category:Melolonthinae]]
[[Category:Insect common names]]