Imagine you’ve baked a cake but it didn’t turn out as you planned. The nearest shop is 1.5h away and the cake needs to be ready within 4h. You’ve got no time to replace the ingredients and also bake another cake. Fortunately, you can separate all the ingredients used and start again. The decomposition process does just that.
What’s decomposition? You may ask. Well, is the process where animal, plant, fungi or any other organism’s matter breaks down. It’s all natural, with no frills attached, and releases essential nutrients back into the ecosystem. Great part of this process is carried out by our beloved insects with a little help from their symbiotic friends. All organisms on Earth will come to a point when they die. Luckily we can’t live forever and this realisation is reassuring.
Carrion (dead animals) left on ground surface will soon be visited by insects. Blow-flies (Calliphoridae) and Flesh-flies (Sarcophagidae) will first appear to lay their eggs. The hatched grubs (larvae) will feed furiously as if bound by a time constrain. Quite right they are. There’s loads of competition for such a valuable resource. Hide beetles (Dermestes maculatus De Geer, 1774) first appear after a few days or weeks. Although, often considered a pest of dry meats, it provides valuable services to humans. It can deliver an estimated post-mortem interval or be used in skeleton preparations. Ants (Hymenoptera) might not be your first though when it comes to carrion but they also play their part. It could be by direct feeding or emission of odours which signals to other insects the presence of a food source. On a different scale, Mayfly larvae (Ephemeroptera) and Caddisfly larvae (Trichoptera) play a role in the decomposition of submerged carrion.
Have you ever noticed Rose chafers (Cetonia aurata) adding extra beauty to your flowers and wonder where they keep their babies? The larvae might be busy at work breaking down your compost pit. Houseflies (Muscidae) can be a nuisance when you’re trying to eat al fresco. These fast flyers have a bigger interest in laying their eggs in carrion, leaf-litter or dung than in our food. Egg survival rates are unlikely once we ingest egg-fly contaminated food. Dung beetles (Scarabaeoidae) is another example of perfect beauty. Although, as all other insects, they aren’t just a pretty face. They collect mammals’ excreted waste and clean up our green areas.
Dead tree logs left in contact with soil will soon be a home for many insects. Contact with soil is important for maximal enzyme function. Enzymes are proteins produced by living organisms which accelerate a chemical process. Soil contact prevents logs from quickly drying out and makes them suitable for an array of insects. Thus, moisture is thoroughly important. Remember this next time you decide to help our saproxylic friends. You don’t need huge logs. Even wood chips left on top of plant pots filled with soil and wood chips will be better than nothing. You might be rewarded by a Stag beetle, Lesser stag beetle or Rhinoceros beetle peeping out ready for mating.
Through the process of wood decay, parasitoids could emerge and conquer. The slim waist of wasps has evolved in junction with the need of flexibility. Their need to direct the ovipositor (insect’s organ at the end of the female abdomen used to deposit eggs) into decaying wood. Subsequently, in some species, has evolved to egg laying directly into other insects. Wood wasps will pierce dead wood or weaken wood with their ovipositor. They will lay their eggs together with a self-carrying fungus. The Sabre wasp (a parasitoid) makes great use of their slim waist. They can detect Wood wasps’ larvae and lay their eggs into the larvae with great precision. Parasitoids are extremely important in agriculture. In many cases they can replace harmful pesticides.
Ambrosia beetles and Leafcutter ants realized that fungi were efficient at breaking down plant cell walls. Fungi can outcompete other organisms in the decomposition race. So, creating a long lasting relationship with fungi was a great idea. These insects have been cultivating crops for over 50 million years. The Ambrosia beetle will create a habitat for the fungus to flourish and in return has a continuous supply of food by feeding on the fungus itself. Leafcutter ants also feed on the fungus but supplies it with fresh leaves instead of self-build wood galleries. The insects will also make sure that the fungus remains in good health by associating with bacteria.
Sadly, many academic institutions are moving away from traditional fields. Expecting that a true understanding of the natural world is not required. We can’t forget the little things in life. They’ve been successful throughout evolution before we even thought of cooking. When the world was getting ready to welcome natural history the doors to the natural world were shut. Although, the eternal need to save humans is forcing human kind to look at insects again. Such as, better understanding in integrated pest management (IPM) to avoid pesticide resistance and reduce crop wastage or decomposition for novel antibiotics.
Author: Ana Natalio @EntoAim