Another Parasite

Regular readers of this blog will know that my wife Bron and I grow a couple of Cabbages in our garden purely for the much maligned Large White Pieris brassicae butterfly. This has been a bumper year for this butterfly and there have been plenty of eggs that have hatched out into tiny caterpillars. Some of these we have transferred into our insect rearing tent for observation purposes.

The photograph above shows that one of these now fully grown caterpillars has several yellow grubs emerging from it. This happened at 10:13 on the 10th July.

At 11:47, the tiny yellow grubs are now in the process of spinning cocoons as seen above.

At 12:08 the cocoons are complete (the caterpillar is still somehow alive at this stage)

We have now decided to separate the cocoons and transfer them into a bio viewer to await the outcome.

Eight days later on the 18th july, the cocoons have hatched out into small black wasps.

Finally the photograph above shows one of these wasps in more detail. It is the Braconid Wasp Cotesia glomerata. The female wasp is capable of injecting about 80 eggs into a caterpillar and the tiny grubs feed, avoiding the vital organs, and emerge just as the host prepares to pupate. It is an important controller of Large White butterflies and, as such, is considered a gardeners friend.