How American newspapers helped discover the effect of hormones on the insects Pyrrhocoris apterus

In the 1960s, researchers breeding Pyrrhocoris apterus insects in Europe noticed a strange phenomenon when they tried to breed the same insects at Harvard University in the USA.

After the 5th stage of development and instead of the insects becoming adults, they either went through a 6th stage of development or became adults with larval characteristics. Some of the insects that went through the 6th stage of development went on to a 7th stage, but ultimately none survived.

The source of the problem

The source of the problem was found in the paper used in the rearing process. The insects only had a problem when the paper towels were made in America.

The researchers were able to reproduce the problem when using paper sheets from American newspapers such as the New York Times, but not when using sheets from European newspapers such as The Times.

After research it was discovered that the cause of the insects’ deaths was a hormone that was only present in paper sheets produced in America.

This hormone came from a species of spruce (Abies balsamea) and other North American coniferous trees whose wood was used in the production of paper in the USA.

This hormone happened to have a strong effect on Pyrrhocoris apterus, but not on other insects, showing the wide variety of hormone receptors present in insects.

The hormone Juvabione

The main component of the hormone was later isolated. It is juvabione, a methyl ester of todomatuic acid.

The hormone juvabione is produced by trees when they are attacked by insects. It mimics the insect growth hormone, protecting the trees from vulnerable pests.

Production and release is regulated by the tree and is time-dependent. Immediately after insect attack, toxic monoterpenes are released. These provide a volatile solvent for diterpene resins so that successive evaporation leaves a barrier that seals the wound site.

So the American newspapers, unwittingly, led to a major breakthrough.