Research shows how pheromones play a vital role in maintaining sociality within the social insect world. The queen pheromones, in particular, are essential for maintaining order within the colonies and correct worker behaviour – without which, chaos ensues.
Social insects such as ants, bees, wasps and termites – the “big four” of the social insect world, are endowed with special glands that produce a dazzling array of chemicals that function as pheromones. The queen pheromone is a special type of pheromone that causes changes in the behaviour of the worker insects. It also plays a pivotal role in the biology and social organisation of insect societies. In spite of their importance, however, to date only a handful of queen pheromones have been studied and chemically identified due to the complexity of the tests.
In a recently published review article from the journal Zeitschrift für Naturforschung C, researcher Abraham Hefetz from Tel Aviv University demonstrates some theoretical aspects of the nature of the queen pheromones and provides examples of systems that have been investigated so far.
Crucial for colony harmony
The harmonious self-organisation system is a hallmark of insect sociality. Almost every aspect of individual or colony behaviour is conveyed through pheromones. These pheromones can be classified into two categories.
The first type, releaser pheromones, stimulate an insect’s immediate behavioural response, and the second type, primer pheromones, affect physical processes that cause behavioural changes. Queen insects have a special type of primer pheromone that is found in social insects. The pheromones that the queen emits inform the workers of her location. They are also essential in maintaining colony unity and worker behaviour, for example, when the workers smell their queen, they adjust their behaviour and physiology.
The “queen bee” (left) is the largest and the only sexually mature female bee in the colony. Worker bees (right) are female but not capable of reproducing. © heibaihui/Getty Images
Chaos and degradation
In the absence of the queen’s guiding pheromone, scientists have discovered a sharp change in worker behaviour, which is shown in intra-nest competition and chaos. With honey bees, the removal of the queen is noticed by the worker bees after about ten hours and results in rapid attempts to find a new queen for the colony. The change in the workers’ behaviour results in reduced foraging efforts as well as reduced care of the eggs, which causes the degradation of the colony.
“The evolution of such an elaborate means of communication enables the performance of coordinated behaviour, particularly in the very large colonies that typify most insect species,” explains Hefetz. “It is also very clear from the abundant research over the past five decades that chemical communication is the major means of communication in social insects.” In contrast, the study of primer pheromones is lacking and only a few such pheromones have been identified given the time-consuming nature of constructing the tests.
Hefetz concludes that further advances in chemical analyses and other genetic tests will enhance researchers’ understanding of the chemistry and mechanisms as well as the crucial role that primer pheromones play in social evolution.
Read the original article here:
Abraham Hefetz: The critical role of primer pheromones in maintaining insect sociality, 28.03.2019.
