Can worms really be loving parents? For many millions of years worms have led a simple life in which they feed off the bacteria that exist in the fermenting environments they live in. Although they have a simple nervous system, they have cleverly learnt to avoid bad bacteria that would harm them. They perpetuate generations using a life cycle in which adult worms self-fertilize and lay their off spring into the bacteria.
Although they have a simple nervous system, they have cleverly learnt to avoid bad bacteria that would harm them. They perpetuate generations using a life cycle in which adult worms self-fertilize and lay their off spring into the bacteria.
This immediately sets up a conundrum, as the parent will be competing for the same food source as their off spring.
A study carried out by my team of scientists at the University of Southampton led jointly by myself and Lindy Holden-Dye and Mathew Wand, together with colleagues at the National Infection Service, Porton Down and KU Leuven in Belgium has revealed that the simple worm – C.elegans (approximately 1mm in length) – may actually harbour an ancient form of parental behaviour designed to benefit their offspring. In other words, they are caring. Our findings were published earlier this month in the journal Scientific Reports.
But why should worms exhibit ‘caring’ behaviour?
Our research showed that before the food source becomes limiting, the parents recognise their offspring and execute a food leaving behaviour to benefit their off spring. Importantly, and enabled by the experimental virtues of the worm, the research found this is dependent on the hormone nematocin, the ancient nematode version of a human hormone called oxytocin. The leaving of food increased over time because the worms that were there were feeding on the bacteria and depleting the source. When we measured the amount of food left by the parental worms we discovered that the number of their progeny influenced the amount of food the adults reserved for them. These hormones are known to regulate sociability and have been called the ‘love hormone.’ Similar hormones serve to bind humans during love-making.
So it would appear that behaviours that ensure our parents are keen to see us eat well have morphed from the ancient organisation of simple nervous systems such as those found in worms.
The paper An oxytocin-dependent social interaction between larvae and adult C. elegans is published in Scentific Reports (DOI: 10.1038/s41598-017-09350-7).