Caterpillar Disease Paralysis

Silkworm

Left: Silkworm caterpillar, sham injected
Right: Silkworm caterpillar injected with bacteria
Photo: Ishii & Colleagues*

Caterpillars suffering from bacterial infections often stop moving and become lethargic. The paralytic proteins (cytokines) present in caterpillar hemolymph are involved. The same contractile paralysis that is initiated by paralytic proteins can be induced by injecting bacteria into the hemocoel of caterpillars. (Note the significant contraction in the photo)  This has been demonstrated* by comparing injection of bacteria to injection of the paralytic protein. The bacteria trigger the activation of the paralytic protein which affects numerous organs and stimulates nitrous oxide release. Is the paralysis adaptive? The answer is unknown. Immobilization may slow the movement of pathogens and confine their location which may make them easier for the caterpillar immune system to eliminate them. Some pathogens are present on food and paralysis will stop a caterpillar from ingesting addition food that may be contaminated.

*Ishii, K., Hamamoto, H. and Sekimizu, K. (2015), PARALYTIC PEPTIDE: AN INSECT CYTOKINE THAT MEDIATES INNATE IMMUNITY. Arch. Insect Biochem. Physiol., 88: 18–30.
doi:10.1002/arch.21215

About jjneal

Jonathan Neal is an Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in by jjneal, Caterpillar Blogging, Environment. Bookmark the permalink.

One Response to Caterpillar Disease Paralysis

  1. Pingback: Caterpillar Disease Paralysis – Entomo Planet

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s