Editing Cockchafer (section)

== 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" />