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Meligethes aeneus F.
Insecta, Coleoptera, Nitidulidae .

Pollen beetle, Blossom beetle, Rape beetle

Description, Biology, Life Cycle, Damage, Common Names, Images

[R]Description
- Adult: 1.5 to 2.7 mm. Upper part of body punctured in a regular manner, green, blue or bronze with metallic glint (*) .
- Eggs: elongated, glassy appearance verging on the milky-white.
- Larva: 4 mm. Elongated, much flattened, yellow-white, covered with light brown dots, head and legs brown.

[R]Biology
- Host plants: rape, Rosaceae, Umbelliferaceae, Cruciferaceae.
- Fecundity: 250 eggs; but high level of adult mortality.
- Egg: time until hatching, 4 to 9 days according to temperature.
- Larva: developmental duration, 27 to 30 days at 16°C; 2 instars.
- pupa: developmental duration, 14 to 18 days.

[R]Life Cycle
- 2 generations per year.
- The adult overwinters at the edge of woodlands or in undergrowth. It leaves its shelter when the temperature reaches 11°C and feeds on the pollen and nectar of various plants (Rosaceae, Umbelliferae and wild Cruciferaceae. When the temperature reaches 15°C, it invades crop Cruciferaceae.
Oviposition begins towards the end of March or beginning of April. The female bites a 2- to 3-mm-diameter hole at the base of flower bud and deposits eggs on the stamens or pistil (*) .
- The larva remains in the flower bud and feeds on the pollen (*) . If more than 5 larvae colonise the flower, the ovaries are damaged. The L2 migrates to other buds then falls to the ground where it pupates in an earthen cell at a depth of 2 to 3 cm.
- The 2nd-generation adult appears at the end of June and attacks the inflorescences of cultivated Cruciferaceae or of weeds and commence overwintering in sheltered situations by the end of July.

[R]Damage
This is caused by the pollinivorous adults (*) . Prior to flowering, the adults bite holes into the buds to reach the stamens and feed on the pollen. The pistil is often damaged, resulting in sterility or premature loss of the flower. Once flowering has begun, the beetle eats the now freshly available pollen and damage is negligible.

[R]Common Names
DE: Rapsglanzkäfer ES: Meligete de la colza FR: Méligèthe du colza IT: Meligete del colza PT: Traça do alho-porro GB: Pollen beetle, Blossom beetle, Rape beetle

[R] Images

  1. Meligethes aeneus (F.) (Coutin R. / OPIE)
    Adult feeding from Viburnum tinus
  2. Meligethes aeneus (F.) (Coutin R. / OPIE)
    Egg Bud opened to show the egg laid on a stamen after invasion by the female.
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  3. Meligethes aeneus (F.) (Coutin R. / OPIE)
    Young larva The larva consumes pollen and nectar.
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  4. Meligethes aeneus (F.) (Coutin R. / OPIE)
    Flower buds destroyed by adults

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