The death, undertaking, and burial process is something we don’t seem to think about too often, especially when it comes to animals (other than ourselves). One group of animals that have quite a particularly interesting undertaking process, as discussed in a recent Science article, are bees. A new study conducted by Wen Ping, an ecologist at the Chinese Academy of Sciences’ Xishuangbanna Tropical Botanical Garden, may have revealed how the ‘undertakers” of the bee world are able to find their deceased hive mates in less than 30 minutes, without the help of released odors of decay.
So how is it done? Wen speculated that the process of locating the dead bees dealt with the lessening of pheromones being released into the air after the bee died, as well as its decrease in body temperature. Like most insects, bees are covered in compounds known as cuticular hydrocarbons (CHCs), which make up the waxy coating on their cuticles that help prevent desiccation. While the bees are alive, these molecules are constantly being released into the air and are used to recognize hive members. By using a chemical method of gas detection, Wen confirmed that cooled dead bees release fewer amounts of CHC molecules than live ones.
To further test his hypothesis, Wen then had to ask: can undertaker bees recognize this change? This led to a series of experiments with Asian honey bees, in which the undertakers removed the regular, cool dead bees within a half an hour. However, after heating the dead bee on a petri dish, it took several hours for the undertakers to notice the body, since it was presumed that the warm dead bee released close to the same amount of CHC as the living bees. Lastly, Wen used hexane to wash off and dissolve the CHCs from the dead bees, in which the undertakers removed nearly 90% of the hot, clean dead bees within a half an hour.
The findings of the experiment suggests that it wasn’t temperature that undertakers used to detect and diagnose death, but the absence of CHC emissions. However, Wen had made a strong case with his study that both the reduction of temperature and CHC emissions lead undertakers to recognize the dead bees and eventually remove them. As stated by Yehuda Ben-Shahar, an entomologist at Washington University, Wen’s study is only the start. Death recognition is an extremely complex process and there may be other components to it besides the ones found by the series of experiments. For example, bees can also “smell” with their antennae and “taste” with their feet, which can both play roles in death recognition. Surely, more research and experimentation must be done in order to fully understand the intriguing process.
References:
ScienceHut 