Oxythyrea funesta, commonly known in Italy as cetoniella or cetonia funesta, is a small black beetle with white spots that is very easy to observe, because it is widespread in our area and also found at some altitude. Just look at pale flowers on a sunny day. For the naturalist it is an interesting insect, for growers an unwelcome guest.
How to recognise the white-spotted rose beetle
It is a beetle of the family Scarabaeidae, subfamily Cetoniinae, about 8-12 mm long. It is black, sometimes with a bronze sheen, with small white spots: usually six in two rows on the thorax and many more on the elytra, the rigid forewings. The body is covered in whitish down that is easy to see in profile and can wear away with age: older individuals look almost hairless.
It is easy to tell apart from the better-known rose chafer (Cetonia aurata), which is larger and a brilliant metallic green. More similar is Oxythyrea cinctella, which however looks uniformly grey, with no obvious spots.
Where it lives and when to see it
It is a heat-loving species, common in central and southern Europe, Mediterranean North Africa and the Near East. In recent decades it has moved further north, for example into Germany. It frequents flowering meadows, gardens, orchards and cultivated land.
Adults fly by day, especially in sunshine. The first appear in spring, usually from April, they are most numerous until July and smaller numbers can be seen until September.
What the white-spotted rose beetle eats
Adults feed on pollen, nectar and fruit juices, but also eat parts of the flower. They are especially attracted to pale flowers, above all white ones, such as those of many Rosaceae. The larvae, on the other hand, live in the soil and feed on decomposing organic matter, such as leaf litter and rotten wood, and on small roots.
Pollinator or pest?
In fact it can be both. As it feeds, pollen from the stamens sticks to its down and can reach the pistils of other flowers, allowing fertilisation and so the formation of fruit and seeds. This gives it a role in biodiversity.
In agriculture, however, it is feared, because it can eat flowers to the point of preventing fruit from forming. The damage mainly affects fruit trees, roses, strawberries and irises, and is worse when adults are numerous during flowering. Those who want to limit it take advantage of its preference for white flowers, on which it is very visible, and remove it by hand. Specific traps also exist, but they do not always work well, because newly opened flowers remain more attractive.
The life cycle
In spring and early summer it is not unusual to see motionless pairs, one on top of the other for several minutes on a flower. The female then lays her eggs in the soil, usually near decomposing organic matter. The larvae, whitish and curved into a C shape, grow to about 2-3 cm.
The species spends the winter in the soil and new adults emerge the following spring, around April. Its natural enemies include the wasp Scolia hirta, which parasitises the larvae.
Does the white-spotted rose beetle sting?
No. If you come across one in a meadow, feel free to photograph it: it does not sting! You can find other insects in my gallery of insects and in the macro world.
