Sexton Beetles

Sexton Beetles are named after the church officer (sexton)tasked with the maintenance and upkeep of the church. In England, one of the duties of a church sexton is to maintain the graveyard including digging graves and burying the dead.

Sexton beetles are attracted to the corpses of dead animals. Sexton beetles are adapted for digging in the soil and will bury the corpse as a way to reserve food for their offspring. Rotting corpses are food for many insects including sexton beetles. By burying the corpse, the sexton beetle can deny many of its competitors access to the corpse. This leaves more food for the sexton beetle larvae.

Blow flies are often the first to arrive on a corpse and can lay substantial numbers of eggs on the corpse before the beetles can bury it. The blow fly larvae grow rapidly and can consume much of the food before the beetle larvae can mature. Burying alone will not protect the food source. Many of the sexton beetles will transport mites, relatives of spiders that are predators of eggs and small insects. The mites (who cannot fly) hitch a ride on the beetles and arrive at the buried corpse. The mites will feed on the blow fly eggs and larvae. Both the mites and the sexton beetles benefit from this interaction.

The sexton beetles often lay their eggs beside the corpse rather than on it, a strategy that protects the eggs from predation by the mites. The beetle larvae have tiny mouthparts that are not strong enough to tear the flesh of the dead animal efficiently. In many species, Mom will use her larger stronger mouthparts to tear and partially chew the food before feeding it to her offspring.

The female beetle will lay an appropriate number of eggs for the size of the dead animal. Over time, the larvae will consume the entire corpse.

After the larvae mature, they will pupate in the soil and emerge out of the ground as fully developed adults. As the adults leave their nest, some of the mites will hitch a ride to the next food source.

Mites Hitch a Ride on a Sexton Beetle

However, blowflies often arrive first and compete with the sexton beetles for the flesh.

About jjneal

Jonathan Neal is a retired Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
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1 Response to Sexton Beetles

  1. Pingback: Living With Food Preservatives | Living With Insects Blog

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