How dangerous is the enemy coming your way? Some animals want to warn each other so that they can flee. An insect, the Californian thrip, which has caused damage in horticulture, can encrypt information about danger in a chemical alarm signal. From NWO research from PhD student Paulien de Bruijn (University of Amsterdam) it appears that the previously considered primitive insects have this skill that was formerly only associated with mammals.
Animals need to stay alert for predators. With these warning signals, animals don't have to use so much time staying alert for danger. It was already recognised that some mammals alter their alert signal depending on the type of danger. Blue monkeys have 3 different alarm sounds for different predators.© Jan van Arkel - predatory bugs attack thrips
Are chemicals as effective as noise?
An alarm can take many forms, such as vocal, chemical, visual and mechanical. Vocal communication was previously thought to be the only way in which the level and nature of the danger could be communicated. But lots of insects use a chemical alarm signal (alarm pheromone). Ecologist Paulien de Bruijn therefore researched whether this pheromone release could be changed depending on the situation, by changing the component elements, for example.
De Bruijn used thrips in her study and exposed the larvae to a relatively safe enemy (predatory mites) or a really dangerous enemy (predatory bugs).
The thrips seemed to change their alarm signal depending on the type of danger. Thrips produce alarm pheromone in dangerous situations. This is a mix of two materials: decyl acetaat and dodecyl acetaat. With an increasing level of danger, the amount of pheromone increased and also the mix was changed.
The variable alarm signal of thrips is far more complex and detailed that was previously thought. Presumably, such alarm signalling can also take place in a lot of other anthropods. The research from De Bruijn therefore asks new questions about the existence and evolution of alarm signals.
Paulien de Bruijn is presenting her doctorate on Tuesday 23 June 2015 at the Instituut voor Biodiversiteit en Ecosysteem Dynamica (IBED) of the University of Amsterdam.
Mw. P.J.A. de Bruijn: Context-dependent Chemical Communication, Alarm Pheromones of Thrips Larvae. Promotors are prof. dr. M.W. Sabelis (†) and prof. dr. S.B.J. Menken. Copromotor is dr. C.J.M. Egas.
The research is financed by the Open Programma of NWO Aard- en Levenswetenschappen.Source: NWO