It is the time of year when skeletons, skulls and bones find their way into biscuits, porch and facades windows.
While the skeleton is considered a symbol of death, the process of turning a newly dead animal into a skeleton relies on the explosion of life that opens up the process of decomposition. Much of this transformation is done by wriggling, flying, and wild insects.
Through decades of careful observation and experimentation, entomologists have described a five-stage decomposition pattern. This model explains how insects, working closely with microorganisms, turn warm bodies into piles of bones, while at the same time recycling carbon, nitrogen, phosphorus and many other nutrients so that other living organisms can development and development.
It starts with a corpse
The first stage of decomposition (called the “fresh stage”😉 occurs between the moment of death and the first sign of flatulence. During this stage, there is no sign of external physical changes, but bacteria that have already lived in the carcass begin to digest tissues in the body.
Insects start to arrive minutes to hours after the animal dies. Most of the insects that inhabit this early period are magnetic flies Family Calliphoridae (Firefly), Family Muscidae (house flies), and Family Sarcophagidae (flies) family.
These early flies searched for primary property to deposit their eggs. This is usually limited to the natural niches of the animal (eg, the nostril or the mouth), or in any external wound (eg, scratches). The moisture and soft tissues in these areas form an ideal nursery environment for young maggots to grow.
Bloom, maggots and methane
Next up is Bloat. During this second stage of decomposition, a lack of oxygen in the body begins to benefit anaerobic microorganisms. These bacteria thrive in the absence of oxygen.
When the bacteria start to release gases like hydrogen sulfide and methane, the abdomen begins to swell. The carcass is beginning to darken and smell bad. Because carcasses are an uncommon and short-lived source of nutrients, many insects can detect and migrate to the flesh for miles away.
During the bulging phase, the eggs hatch and a large number of maggots begin to eat. At this point, the scarab is engaged in a frenetic foraging. Some species of beetles, such as the carnivorous beetle, will eat the nutritious flesh of the carcass.
Predator bugs, such as mobile bugs and clown bugs, come to eat the maggots.
Maggots operate their magic
The third stage is called “active decay”. This phase begins when the carcass begins to deflate slowly, a process similar to a nail stabbing a tire. Young worms gnaw small holes in the body cavities, allowing air to escape.
The tissues begin to liquefy, giving the carcass a wet appearance, followed by a stench. At the end of the active decay stage, the maggots focus on feeding in the chest cavity of the animal. Beetles soon dominated, with large numbers, large numbers of mobile bugs and clown bugs coming to eat the maggots.
When most of the meat has been eaten up, the carcass will go into a rotting stage. The stench of the carcass begins to subside, and most maggots leave the carcass to pupate in the soil below.
Next, the adult dermestid scarab reaches the carcass and begins to lay eggs. Dermestid beetles – small round beetles covered in small scales – are scavengers that eat a variety of dry materials: fur, feathers, dead plants, even carpets!
If they are unfamiliar to you, you probably haven’t looked closely – a 2016 survey of indoor vertebrates found the dermestid scarab beetle in 100% of households.
The Dermestid scarab gets the job done
The final stage of decomposition is called dry decomposition. Very few adult flies are attracted to the carcass at this stage. During dry decomposition, carcasses are transformed into bones, cartilage, dry skin, and hair. By this stage, there is very little odor.
The Larval dermestid beetles continued to clean the skeleton, leaving remains that looked very much like a disassembled one. In fact, Dermestids are so effective at cleaning bones, that they are often used by museums when preparing skeletons for collection and display.
Little things run the world
While witnessing this amazing act is not for people with an upset stomach, the decomposition of the animal carcass is a fundamental process that helps circulate nutrients in the ecosystem.
Nutrients like carbon (the basis of all life on Earth), phosphorus and nitrogen, which all organisms need to thrive, are in limited supply in ecosystems. They must be continuously reused and recycled to ensure the continuation of life.
After decomposition, the soil layer below the cadaver will contain a high content of nutrients compared to the surrounding ecosystem.
However, nutrients released into the environment do not all stay in soil and plants. The nutrients and energy contained inside dead animals (whether rats, raccoons or crows) are recycled and repackaged into live and breathing insects.
When these insects finish eating their flesh, they disperse into the wider environment where they continue to be useful members of the ecosystem.
It is these insects that help pollinate our crops (including pumpkins), fill the belly of predators (such as bats), and are important for the decomposition of Other dead creatures (like mice, toads and snakes).
If you happen to see animal bones this Halloween or any other time of the year – take a moment to consider the beastly movie that made this discovery possible.
Paul Manning, Postdoctoral Research Fellow, Department of Agriculture, Dalhousie University.
This article is republished from The Conversation under a Creative Commons license. Read the original article.