Every minute two million plastic bags are used throughout the world. Most of these bags are thrown away within 20 minutes and end up on a landfill or in the environment. Plastics (malleable, ductile, and impervious in nature) is being used and produced 7.8 billion tons - more than one ton of plastics for every man alive today. As of 2018, about 380 million tons of plastic is produced worldwide each year. From the 1950s up to 2018, an estimated 6.3 billion tons of plastic has been produced worldwide, of which an estimated 9% has been recycled and another 12% has been incinerated (https://www.economist.com/international/2018/03/03/theknown- unknowns-of-plastic-pollution/).

Have you ever heard there are some insects that are capable of eating plastic and digest them? Yes you read it right there are many insects who has capacity to eat plastics and one among them is  Greater wax moth (Galleria mellonella), the honey comb moth,  member of family pyralidae, which is also considered as the serious pest of the bee industry, is also known for its plastics digesting ability. Scientists say a common insect — the wax worm — could be the answer to this global pollution crisis. In their new research published in the science journal, Current Biology, a team of European scientists reveal that the larva of the wax moth can easily chew through the common plastic, polyethylene due to the presence of plastic digesting enzyme.  Furthermore, they also reported that  the worms can chew big holes in a plastic shopping bag within 40 minutes. The findings were actually discovered by accident — the scientists noticed plastic bags containing the wax worms became permeated with holes. After 12 hours, the bag was significantly shredded and scientists found the worms had left behind ethylene glycol, a sign they really did break the plastic down. Though the insects don’t normally eat plastic, wax moths lay their eggs in beehives and the worms hatch and live on beeswax, which is described by lead researcher Federica Bertocchini as “a sort of natural plastic.” The scientists believe it’s possible the digestion of beeswax and polyethylene could involve similar types of chemical bonds. “We are planning to implement this finding into a viable way to get rid of plastic waste, working towards a solution to save our oceans, rivers, and all the environment from the unavoidable consequences of plastic accumulation,” Bertocchini said. “However, we should not feel justified to dump polyethylene deliberately in our environment just because we now know how to bio-degrade it.” Greater Wax Moth (Galleria mellonella), honey comb moth, a holometabolous insect, belongs to Lepidoptera order, completes its lifecycle through egg, larva, pupa, and adult.

In 2014, another team of scientists found bacteria in wax worms’ digestive systems could start degrading polyethylene after two months — not nearly as quickly as Bertocchini’s sample. But Woods Hole Oceanographic marine biologist Tracy Miner told National Geographic the focal point should still be on recycling more and producing less plastic.

In the past year realizing the importance of this research our senior from my University also conducted research entitled “The Feeding Potential of Greater Wax Moth (Galleria mellonella) in Different Gauzes of Plastics”. Their study and experimental set up were:

Experimental Site and Set Up

The study was conducted in Entomology laboratory 27.48013ºN 83.44730ºE, Institute of Agriculture and

Animal Science, Tribhuvan University, Paklihawa Campus. The research was conducted under ambient lab condition in two different seasons (Sept-Oct & Jan Feb). Glass bowls of 5cm×2.5cm size were used. Plastics of three different gauzes (200,300 & 500) were brought. Four treatments were made and each was replicated 10 times. The treatments were:

T1: Plastics of 200 gauze

T2: Plastics of 300 gauze

T3: Plastics of 500 gauze

T4: Bee Wax (Natural feed)

Summary: The study  concluded that rate of plastic feeding was significantly higher in summer than in winter. Change in area for 200 gauze of plastic was significantly higher than 300 & 500 gauze i.e. area of plastics consumed by the larva decreases with increase in gauze of the plastic. But the rate of change in weight was asimilar for three gauzes of plastics. Consumption in winter season was relatively lower than the summer season. Inside the closed environment, in appropriate temperature and life stage of larva, it seems good to use these larvae in order to make them feed upon the plastic refuses. However, the further research should be conducted because they may be churning these wastes and digesting through some sophisticated mechanisms inside their gut. So, if we  became able to know that mechanism and create such type of environment artificially it could lead us to the way out of this plastic ruins. (Author’s Summary)

References:

 http://www.nepjol.info/index.php/IJASBT/article/download/29594/23831/