Mammoth wasp - Megascolia bidens

Mammoth Wasp (Megascolia (Regiscolia) maculata flavifrons) Avispa parasita de cuatro puntas

This is a very large solitary wasp, the female reaching up to 4.5cm whereas the male is a little smaller. This species appears in warm weather during late May, June, July and August. They hold no danger to humans despite their size and black / yellow warning colours. (Above image Megascolia bidens)

They feed eagerly on flower nectar and this is the best time to view them.

Megascolia flavifrons male and female examples

Mammoth Wasp (Megascolia (Regiscolia) maculata flavifrons) Avispa parasita de cuatro puntas
Mammoth Wasp (Megascolia (Regiscolia) maculata flavifrons) Avispa parasita de cuatro puntas

Left: Female showing yellow head Right: Male, note long antennae

The larger female can be told apart by her yellow face and short antennae. The male has a black head and longer antennae. Both have two yellow bands on their abdomens which can sometimes be divided to form 4 spots, which is more evident on the female in these pictures.

You may see several of these wasps flying around decaying tree stumps, they have a purpose here. They are searching for larvae of a particular beetle.

Inside the rotten wood may be young of the Rhinoceros beetle (Oryctes nasicornis). The female Mammoth wasp, once she has discovered the huge larvae, will sting one to paralyze it and then lay her egg on the outer skin.

Mammoth Wasp (Megascolia (Regiscolia) maculata flavifrons) Avispa parasita de cuatro puntas
The rhino beetle larvae is the food supply for the larvae of the mammoth wasp. Left: Rhinoceros beetle (Oryctes nasicornis) Right: Rhinoceros beetle Larva.

On hatching, the larvae of the Mammoth wasp will eat into its host thereby killing it. The larva of the wasp then creates a cocoon near to the meal remains. It will stay in this cocoon over winter and hatch out once the spring weather warms sufficiently.

Family: Scoliidae

  • Scientific name: Megascolia (Regiscolia) maculata flavifrons (Fabricius 1775)
  • Also accepted as Scolia flavifrons

There are several very similar species within Iberia, including:

Megascolia bidens
Megascolia bidens showing yellow antennae
  • Megascolia bidens – always has coloured antennae, either reddish or yellow.

Other mammoth wasps

  • Scolia erythrocephala – has more than two yellow bands
  • Scolia hirta – two yellow bands and a violet tinge on wings
  • Scolia hortorum
  • Scolia sexmaculata – has six yellow spots

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