18 Jun 2018 Spider Hunting Wasp by Ranger Jason Botes
National insect week is finally upon us, allowing us to share weird and wonderful facts about insects.
Today I am going to be telling you about one of the more interesting insects I have come to learn about over the years as a ranger, it is certainly one we all know about and tend to fear every once in a while, especially we hear that loud buzzing of the wings. No, it is not bees or your average joe wasp, this is about the spider hunting wasp.
This incredible insect belongs to the family Pompilidae, and can be found all across the world. There are 6 sub-families with around 5000 different species.
It is unique from other wasps, as they are solitary and they predominantly hunt spiders, therefore giving them the name spider hunting wasps.
These wasps are relatively easy to identify from other species through various Methods. Firstly, they will be on their own, secondly, their colourings, as they stand out with being black and having brighter aposematic colours such red, orange, yellow and even metallic colours. Size is also a factor, some may be as small as 10mm and others as large as 60mm.
Now as mentioned earlier the spider hunting wasp received its name through the act of hunting spiders, the way they achieve this, is to fly around low to the ground, or walk up and down on a tree trunk, seeking their prey. Once a spider is found, the spider hunting wasp will deliver a quick blow with its stinger, injecting small amounts of venom into the spider. The venom however, does not kill the spider, but paralyzes it instead, keeping the prey alive and fresh.
Depending on the size of the spider, the female wasp will lay and deposit one egg on the inside of the spider itself and either bury it straight away or drag the prey back to a pre-dug out burrow. Once inside the burrow the female will exit and cover the entrance with balls of mud, allowing for the egg to incubate and eventually hatch and the spider will be the first meal and only meal through development.
Therefore, the female must ensure the size of the spider is large enough to sustain the developing larvae.
What is also quite fascinating, is that the size of the prey/host can help determine the sex of the wasp. Generally, the larger the prey, the new wasp will be a female (as females tend to be larger than males), and the smaller prey will generally produce the smaller male wasps.
After the edible parts of the spider has been consumed, the larvae will spin a silk cocoon and pupate.
Some species will lay an egg on the back of a living and active spider and the hatched larvae will feed on its prey externally until the spider dies and the larvae will spin a cocoon and pupate.
Adult spider hunting wasps do not feed on spiders themselves but are actually nectar feeding insects and feed on a variety of plants and will only catch spiders when ready to lay eggs.
So, keep your eyes open, the next time you see a wasp flying around looking like its showing odd behavior compared to other wasps, take a closer look because it may just be a spider hunting wasp looking for its next victim for the future generation.