The aptly named Mammoth Wasp (official name Megascolia maculata) is an intimidating-looking insect, but despite its black and yellow ‘warning’
colours, it is not dangerous to people – well, they can sting but will not aggressively seek you out as a target. They are absolute giants – we had a ‘close encounter’ once and we both staggered back in alarm as this ‘thing’ flew at us, and we frantically batted it away with some well-known expletives as well as our hands!
They are large impressive insects, and females may grow to reach 6cm in length - that’s over 2 inches! Males are a little smaller and differ slightly in their appearance, females have a yellow face and short antennae, while the smaller males have a black face and longer antennae (not that I will be waiting around long enough to check out the differences!). Both are marked with yellow bands on their abdomens, which may be broken and show as four yellow spots.
First instinct was that it might be a hornet, they are the ones to really be aware of as they are quite capable of multiple stings and can cause serious pain, or even death if you are highly allergic to insect venom. But looking up the differences, we found that the Asian Hornet – the one that is on its devastating way across Europe, invading bees’
nests and killing all occupants on route - looks different, in that the head is orange and has a ‘pointier’ body, and they tend to swarm, rather than be a loner, which is what a Mammoth Wasp is.
The Mammoth Wasp might be seen during the summer months seeking nectar from flowers, but the female’s prey is the rhino beetle which are found in or around decaying wood or tree stumps. She will inject the beetle’s larvae with venom to paralyze it, then lay a single egg on its outer skin. When the egg hatches it munches it’s way through the unwitting and helpless beetle host, thus killing it. The wasp larvae will then build a cocoon close to the host’s remains, and will stay there until the spring, when it emerges as an adult.
These bugs are not uncommon in Portugal and only the female has the sting, so if you see one recklessly flying your way, just stand aside – it’s not after you but a flower or a rhino beetle!