Monday 13 July 2015

Sexton Beetles-The undertakers of the insect world




When you think of an undertaker, you probably think of a pale, middle aged man with bags under his eyes, who wears black clothes and has a number of selfies on his phone that he has taken with his dead colleagues (or maybe that last ones just me). However, I bet you’ve never considered that undertakers exist in the insect world.


The Sexton or Burying beetle (pictured) has the strange behavior of burying animal corpses it finds such as of shrews, rats and birds. 

When an animal dies, its pungent aroma can be sensed by these beetles due to chemoreceptors they have in their large antenna, and a single decaying animal can attract many of these beetles to the same corpse. This can lead to a number of beetles fighting one another over this valuable food source (males fighting males and females fighting females) until one couple remains afterwards who then goes on to mate. 

However if a male finds a food source with no female, he can release a pheromone to attract one, and a lone female may be able to raise a family on this food source with the use of sperm she may have stored from previous matings.



After a male and a female find each other on a corpse, the new couple will begin digging a hole underneath to bury it. As they do this, they remove all of the fur and cover the animal in  anti bacterial and anti fungal secretions, as well as other substances. This not only slows the decay rate of the corpse, but it also decreases the pungent smell of the corpse so as not to attract hungry animals, as well as rival Sexton beetles towards it. 

Sexton beetles also cleanse the animal corpse further due to small mites that they carry upon them wherever they go. When a Sexton beetles finds a corpse, these mites feed on the eggs and larvae of other insects that may be found on it already, making it more sterile which is what the adult beetles want. As the mites are able to feed, and the beetle has a more sterile corpse, this beetle/mite relationship is beneficial to both parties.



But why do Sexton Beetles go through all of this hard labour? Well it is all done for the reason life on earth does anything at all. For the purpose of reproduction.




The female will then go on to lay her eggs on the soil around the corpse. Once the eggs have hatched, the larvae will move into the corpse and make complete use of the huge, protective long-lasting food source, compliments of their loving parents. Although the parents have created this haven for their offspring, they will spend time digesting and regurgitating food for them. 

After a few days the larvae will leave the corpse and enter the soil where they go on to pupate, and change from their larval form into full grown adult beetles.


-Thomas Glen

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