Alien vs Predator in real life? Introducing the Glomerata wasp!

One of the most iconic scenes in film history: watching a parasitic alien ripping through its host’s chest as it enters the world in the Alien movie franchise. The very thought of this happening in reality is shuddering, yet, there is an insect which does something much worse. Meet Cotesia glomerata, a parasitic wasp known as the Glomerata wasp.

Cotesia Glomerata attacking cabbageworms. Photo: Hans Smid

The terrifying process begins when the unsuspecting cabbageworm feasts on a cabbage leaf. The plant releases a pheromone (Andre, 2012), attracting the wasp. The adult female wasp impregnates the caterpillar by ‘stinging’ and injecting it’s eggs into the would-be host. The eggs are coated with a virus which disables the caterpillar’s immune system, allowing the wasp larvae to survive within.

Cotesia glomerata larvae inside the caterpillar. Photo: Christie Lynn


The larvae incubate inside the caterpillar for about 2 weeks, growing to the size of a grain of rice. The caterpillar swells and eats 1.5 times it’s normal diet to sustain the larvae within. It’s interesting that while the larvae consume the caterpillar from within, they are careful to keep it alive, avoiding vital organs.





Upon maturity, the larvae use their saw-like teeth to slice their way out of the pitiful host. Up to 60 larvae emerge from the caterpillar and start weaving cocoons, preparing to enter their next stage of life. Surprisingly, the caterpillar is still alive despite its wounds.

Cabbageworm defending Cotesia glomerata cocoons. Photo: Alejandro Torres Ruiz

Here’s the twist; the caterpillar is seemingly mind-controlled and weaves an additional layer of protection around the wasp cocoons, spending its remaining days fending off would-be predators until it succumbs to starvation and wounds. Quite a grisly ending for this caterpillar. Imagine hosting 60 foreign organisms in your body which devour you from within and brainwash you for their nefarious purposes while they tunnel out of you. There are other parasitic wasps that target infected caterpillars, in a gruesome battle for the host. (Poelman et al., 2012) Talk about wasp-ception.  I’m just glad these insects don’t target humans.


Watch this video from National Geographic to find out more about Cotesia glomerata!


1) E.H Poelman, M. Bruinsma, F. Zhu, B.T. Weldegergis, A.E. Boursault, Y. Jongema, J.A. Joop & E.M. Louise, 2012. Hyperparasitoids Use Herbivore-Induced Plant Volatiles to Locate Their Parasitoid Host. Public Library of Science Biol 10(11): 1371-1435.

2) “This week’s Sci-Fi Worthy Parastite: Cotesia Glomerata” by C. Lynn. Observations of a Nerd, 1 May 2009. URL: (Accessed on 03 April 2013)

3) “Wasps that lay eggs in wasps that lay eggs in caterpillars” by Ed Yong. National Geographic, 27 November 2012. URL: (Accessed on 03 April 2013)

4) “Plants call for help brings enemies too” by Kate Andries. National Geographic, 30 November 2012. URL: (Accessed on 03 April 2013)


“Body Invaders” by National Geographic Youtube Channel, 27 April 2009. URL: (Accessed on 03 April 2013)


1) “The parasitic wasp Cotesia Glomerata” by Hans Smid. Bugs in the Picture: Larval Parasitoids. URL: (Accessed on 03 April 2013)

2) “Cotesia Glomerata larvae” by Christie Lynn. Observations of a Nerd: This week’s Sci-Fi Worthy Parasite: Cotesia Glomerata. URL: (Acessed on 03 April 2013)

3) “Pieris brassicae parasitada” by Alejandro Torres Ruiz. Flickr Gallery: EntomoAgricola. URL: (Accessed on 03 April 2013)