The potter wasp Odynerus spinipes is an impressive creature. A long abdomen with yellow lined abdominal plates all of an equal size save for the second which is enlarged to show an expanse of black.   The rest of her body is predominantly black, with yellow flashes on her legs and face.

 

In early Summer she finds a promising patch of clay cliffs and picks her nesting spot. Instead of merely digging a hole and laying an egg in the bottom like other wasps, she does something far more creative.  After digging a burrow she will begin to collect soft clay from a puddle before slowly constructing a chimney. About 3cm high and curled over at the top to prevent rain from entering, the chimney is now complete. A nest cell is now formed at the bottom of her burrow and an egg is laid, attached to the cell wall by a fine thread.

 

Construction complete, she now has to provide food for her larva when it hatches. The larva has very specific tastes and the adult wasp has to know exactly where to find the food to satisfy this fussy little eater. The larva will eat only the grub of a specific weevil species, Hypera plantaginis.  which lives on Bird’s-foot Trefoil. The wasp can be seen darting forward and back across this habitat using her eyes and chemoreceptors in her antenna to locate her prey. Whenever she finds one she stings it to paralyse it before clutching the grub to her chest and flying back to her nest. She paralyses rather than kills it, keeping it alive to ensure that it does not. She drops the grub on top of the egg cell for her larva to eat when it emerges. She will provision her nest with up to 30 weevil grubs before deciding that her larva will have enough to eat.

There is, however, one more thing the mother Odynerus spinipes has to deal with: the threat of a parasitoid wasp.
Jewel like in her appearance, the villain in question is a beautiful creature. Her name is Chrysis viridula, and she is specifically adapted to target Odynerus spinipes. She will spend her time zipping back and forth along the clay banks searching for a chimney she can use.

Once she has found one she will tentatively patter about the entrance to the hole, attempting to determine whether the occupant is home or not.

If she is surprised by the home’s occupant she is well equipped should the owner attack. Her beautiful exoskeleton is also extremely thick and hard, protecting her from stings. If it all gets too much and the ferocity of the attack is too hard to bear she has another, quite endearing trick. As the underside of her abdomen is concave she can curl herself up into a tiny ball, protecting herself from the onslaught by the home’s occupant.
If she remains undetected however, she will reverse into the wasp’s home and lay her eggs right beside the wasp’s eggs. Her eggs hatch first and will proceed to eat the host’s eggs. This all goes undetected by the O. spinipes and she will seal up her nest hole for the winter just as she would normally, unaware of the ‘cuckoo’ that has infiltrated her nest.

Chrysis viridula and Odynerus spinipes

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