The common cockchafer, Melolontha melolontha, is a rather large beetle that flies about noisily, emitting a loud whirring noise. It is more commonly known as the May Bug and it gets this nickname as it commonly emerges in early May and is seen frequently during this time. Due to its large size and clumsy flight, it can cause quite a stir when seen and social media is often full of enquiries about this beetle. So, now that we are in the peak season for this species, here’s all you need to know about the cockchafer.
The common cockchafer is a fairly large beetle that can grow up to 3.5cm in length. It is the UK’s largest chafer species. They have rusty brown elytra (wing cases), brown legs, a black thorax and a black head. They are covered in short hairs which can give them a ‘dusty’ appearance. They also have whitish markings on their abdomen, which can be seen under the edges of their elytra.
They have rather spectacular orange antennae that have a beautiful fan-like tip. These antennae also help us to determine the sex of the beetle as males have 7 leaves in their fan-like tip and females have only 6.
The common cockchafer differs from similar chafer species by having a pointed pygidium, which is a segment at the end of their abdomen. This pygidium often leads people to believe that this species can sting, but do not worry– this beetle cannot sting. The pointed pygidium is actually used by females to push their eggs into soil.
The larvae look considerably less attractive than their adult counterparts. They are white, with reddish/brown heads and appear C-shaped due to their curved body. They have 3 pairs of reddish/brown legs. They grow up to 4.5cm and can be easily confused with other chafer beetle larvae and stag beetle larvae.
Cockchafers lay their eggs into soil in the summertime, roughly in June/July and these eggs then hatch into the fat, white larvae. The larvae spend their lives living within the soil, feeding on plant and grass roots. They do this for a period of 3 years (sometimes 4-5 years in colder climates) until they reach a length of 4cm-4.5cm. Once they reach this size, they move deeper down in the soil and pupate. They emerge as adults in autumn but stay buried until spring. They surface in either April or May, depending on how warm it is. Adults survive for 5-6 weeks and during this time they mate, with females being able to lay up to 80 eggs.
Although adults are often seen, due to their noisy and rather clumsy flight, larvae are less commonly seen. Gardeners tend to come across the larvae most often, whilst working in the soil.
Adults can often be found in gardens and they frequent hedgerows, parks and grasslands. Adults chew on the leaves of trees and flowers so can often be found flying near the tops of trees.
Adults are attracted to light and can often be heard bumping into lighted windows during May. Due to their nature of flying at the height of tree tops, they also regularly come into contact with chimneys and have been known to fall down them on occasion. They are mainly seen (and heard) during the early evening from May until early July.
Cockchafer larvae can be a pest of some cereal and vegetable crops when present in large numbers. Because of this, the beetle was subjected to heavy pest control throughout history. Before pesticides came on the market, cockchafers were controlled by the collection and killing of adults, which worked moderately well. Then, in the 20th century, pesticides came on the market and unfortunately this caused cockchafer numbers to decline dramatically. Thankfully, new regulations regarding pesticide use came into effect in the 1980’s and since then their numbers have began to increase.
Cockchafers are currently wide-spread in Britain.
NatureSpot, (2017). Common Cockchafer- Melolontha melolontha. [Online] Available at: http://www.naturespot.org.uk/species/common-cockchafer. [Accessed 06 May 2017].
National Insect Week, (2017). Cockchafer (May-bug). [Online] Available at: http://www.nationalinsectweek.co.uk/discover-insects/beetles/cockchafer-may-bug. [Accessed 06 May 2017].
Discover Wildlife, (2017). 7 things you never knew about the cockchafer. [Online] Available at: http://www.discoverwildlife.com/animals/7-things-you-never-knew-about-cockchafer. [Accessed 05 May 2017].
The RSPB, (2017). The RSPB: A to Z of a Wildlife Garden: Cockchafer. [Online] Available at: https://www.rspb.org.uk/birds-and-wildlife/bird-and-wildlife-guides/a-z-of-a-wildlife-garden/atoz/c/cockchafer.aspx. [Accessed 05 May 2017].
Royal Horticultural Society, (2017). Chafer grubs in lawns/RHS gardening. [Online] Available at: https://www.rhs.org.uk/advice/profile?PID=487. [Accessed 05 May 2017].
Buglife, (2017). Common cockchafer. [Online] Available at: https://www.buglife.org.uk/bugs-and-habitats/common-cockchafer. [Accessed 05 May 2017].
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