Plants are constantly attacked by insect pests, and they have mechanisms
to defend themselves, including chemicals or sturdier leaves. Now,
researchers have found that when wild black mustard plants defend
themselves against an initial enemy, they already anticipate the need to
later fend off other, different enemies and prepare for the most likely
sequence of attackers.

Researchers Daan Mertens and Maite Fernand??z de Bobadilla from the team
headed by Erik Poelman in the Laboratory of Entomology at Wageningen
University & Research (WUR) showed how a plant's strategy works. They
observed the defense mechanism used by black mustard on 90 combinations
of insect attacks and linked these results to three years of research
into the frequency of the interactions on plants in the wild. Similar
tests in the past were limited to five combinations only.

Poelman explains that the old idea that insects feeding on plant sap
triggers a reaction that then diminishes a plant's potential defense
against caterpillars has turned out to be too simple. Their work has
confirmed the plants' physiological reactions against aphids and
caterpillars, and also reveals that in many instances the plant does not
become more susceptible to insects with a different feeding pattern.
"Particular combinations or sequence of insects in the wild appear to be
better predictors of resistance than the characteristics of the
individual insect species," Poelman added.

Plants can prepare for insect attack sequence - WUR
[www.wur.nl]