Updated: March 5th 2023
There are 4 key stages of the wasp life cycle.
As with bees, wasps pass through the phases of egg, larva, pupa, and then emerge as adult wasps.
This process is the same for social and solitary wasp species, despite the tremendous variation in factors such as the immediate environment of developing offspring, and lifespans of different species.
For me, the wasp life cycle is interesting. But why digress into the subject of wasps given that this website is about bees?
Bees are descended from sphecoid wasps, and as such, bees and wasps are related.
Along with ants and sawflies, they both belong to the insect order hymenoptera.
Here. we'll look at the stages of the wasp life cycle, whilst highlighting examples of a few of the many variations.
As with bees, the life cycle of the wasp starts with the laying of an egg by a fertile (mated) female wasp. Where this egg is laid depends on the species of the wasp.
For example, in social wasps, the queen of Polistes species lays her eggs in cells she herself constructs from plant matter. These whitish eggs resemble small grains of rice poking up from the bottom of each cell.
In contrast, potter and mud dauber wasps lay a single egg inside a ‘pot’ the female builds from clay and mud.
Braconid wasps in the genus Cotesia have an entirely different strategy. The females target caterpillars, such as the Carolina Sphinx Moth caterpillar (also known as Tobacco Hornworm), Manduca sexta. The wasp lays around 65 eggs in the hemolymph (invertebrate ‘blood’) which develops into a larva inside the body of the caterpillar2.
A similar strategy is employed by the jewelled cockroach moth, a predator of pest cockroaches. The activities of such parasitic wasps are regarded as beneficial to the environment, as well as providing natural ‘pest control’.
As with bees, fertilized eggs become female wasps, unfertilized eggs develop into males.
Larvae spend their time eating and growing (and molting) inside the cell or cavity in which they developed from an egg.
As they molt (a process regulated by the insect’s hormones), they shed their exoskeletons, and expand whilst the new exoskeleton still remains sufficiently supple.
Intervals between molts are called instars, and Eaton notes there are on average 3 – 5 instars although the number varies1.
Many wasp species rely on high protein foods consisting of other invertebrates which are hunted by the adult and are provided as dead prey.
Other species provide live invertebrate food, such as single spiders or flies, which are paralyzed and placed whole inside the larval cell. They remain alive until eaten by the wasp larva.
In other cases, the wasp larva grows inside the host, eating it from the inside.
The larvae of some wasp species are vegetarian. The gall wasps for example, rely on cellulose (plant matter) provided by a gall they induced to form in the host plant.
In some species, the larva will undergo a prepupa stage that lasts through winter.
As with bees, there are species that form cocoons.
The image below may appear to show eggs on the body of a Tobacco Hornworm Caterpillar, Manduca sexta, but the white rice-shaped objects firmly attached to its body are actually cocoons of a Braconid wasps, Cotesia congregata.
The larvae erupt from the body of the caterpillar synchronously to pupate2.
The larvae of paper wasps grow and develop until they fill the larval cell in which they hatched from egg.
They then begin spinning a silken dome over the cell, after which, they will begin to pupate.
As the wasp pupates, it goes through a transformation process, growing legs, wings, and developing visibly separate body parts (head, thorax, abdomen) and eyes.
Eventually, once development is complete, the adult will chew its way through the nest cell or cavity if necessary, and emerge as a fully grown adult wasp.
Overwhelmingly, wasps perform an important function in the ecosystem, including natural pest control and plant pollination.
If you are concerned about wasps you can take action to deter wasps without killing them.
Bees and wasps are commonly seen foraging on the same shrub. However, wasps will sometimes attack bee nests, usually hunting invertebrate matter to feed to wasp larvae.
Bees can usually repel an occasional wasp (and some honey bee species have even developed strategies to defend themselves against hornets), but a large number of wasps could be a challenge of a bee colony.
Should I kill wasps to protect bees?
The best way to help bees generally is not by destroying wasps, but by filling our gardens with plants for bees and cutting out harmful insecticides. This will go some way to help reduce the impact of habitat loss.
1. Eric R. Heaton; Wasps – The Astonishing Diversity Of A Misunderstood Insect, Princeton University Press 2021.
2. University Of Florida, Featured Creatures - Cotesia congregata.