Review on Insect-Mediated Composting Methods

Composting is a natural process of decomposing organic materials such as food scraps, yard
waste, and other biodegradable materials under controlled conditions. It is a process that mimics
nature's way of breaking down organic matter into a rich, dark, and earthy-smelling soil
amendment called compost. Composting can be done in various ways, including using a compost
bin, a compost tumbler, or simply creating a compost pile.
Insect-mediated composting is a method of composting organic waste using the larvae of certain
insects, such as black soldier flies, red runner cockroaches, dermestid beetles etc. In this process,
the insects consume the organic waste, breaking it down into simpler compounds and producing
nutrient-rich compost. Insect-mediated composting is a sustainable and efficient way to manage
organic waste, and it has gained attention as a potential solution for addressing the growing
problem of waste management in many countries.
Information on insect-mediated composting was gathered from secondary data sources. These
sources identified black soldier fly larvae, red runner cockroaches, dermestid beetles, dung
beetles, mealworms, and soldier beetles as suitable insects for composting. However, challenges
were encountered while collecting data from various sources. Future research could explore
comparative studies of these insects in the composting process.
The present paper concludes that the insects used in composting are Black Soldier Fly Larvae,
Red Runner Cockroaches, Dermestid Beetles, Dung Beetles, Meal worms, Soldier beetle. It was
observed from table 2 that majority of the insects (Dermestid Beetles , Dung beetles, Meal worm,
Soldier Beetles ) undergo four main stages i.e Egg, Larvae, pupae and adult in life cycle.
However black soldier fly larvae (BSFL) have five stages of family life cycle while red runner
coackroach has 3 stages of life cycle. Larval stage was the longest phase of the life cycle for
dermestid beetles, dung beetles, Meal worms and soldier beetles; adult stage was longest phase
for red runner coach where as larvae and pupae stages are the longest phases for black soldier fly
larvae (BSFL). Table 3 revealed that more or less same steps were found in processing the
compost by these six types of insects. feasibility of rearing of the insects at household level was
observed, only black soldier fly larvae (BSFL) found to have low space requirements, low
maintenance with efficient waste reduction and production of protein(Table 4). It was observed
from table 5 that all 6 types of insects can compost at commercial level by following the same steps that
have been observed in household-level composting. Organic waste, such as fruit and vegetable
scraps, food waste, agricultural waste, and animal manure, is collected from different sources. The waste
is sorted and processed to remove any non-biodegradable materials. Reasons for feasibility of
black soldier fly larvae (BSFL) rearing at commercial level revealed that high reproduction rate,
high feed conversion efficiency, low maintenance, multiple revenue strings and environmental
benefits (Table 6). Various countries were rearing different types of insects for composting the
waste. Except soldier beetle rest of the five types of the insects are being reared in USA (Table
7). When insect rearing places were observed in India it showed that soldier beetle is not being
reared in India at all. While Karnataka, Tamilnadu and Maharashtra states are rearing other five
types of insects (Table 8). Since these insects are pretentious food, its consumption
and acceptance in different countries was observed (Table 9). Mexico Thailand, China, Vietnam,
Cambodia and many African countries consume these insects by roasting or frying. In US and
Europe there is a growing interest in edible insects. However several constraints were observed
to promote insects for consumption in India (Table 10) i.e majorly cultural barriers followed by
lack of awareness, regulatory challenges, environmental concerns and legal barriers. The
technology and equipment is necessary for large scale production and processing of insects for
human consumption is not readily available. Compost generated by these six types of insects has
good nutrient content so that it can be used for plants as fertilizer (Table 11). Insect composting
has a positive effect on reducing the release of green house gases (Table 12).It was noticed that
insect mediated compost reduces the emission of carbon dioxide, methane and nitrous oxide.
Benefits of the insect mediated compost were analysed in Table 13.Various advantages observed
were reduced waste disposal cost, increased nutrient value, improved soil health, reduced green
house gases emissions, reduced water usage and enhanced biodiversity, plant growth and yield.
Advantages of insect mediated rearing in India were found to be effective organic waste
management, biodiversity conservation, sustainable lively hood, reduction in chemical fertilizer
use and low maintenance (Table 15). Insect mediate rearing in India found to face certain
disadvantages like high cost of infrastructure and maintenance lack of technical knowledge rules
and regulations , limited market demand and climate sensivity. India has a large growing
population that present’s the significant market for insect based enterprises which depend on
various factors like demand for insect byproducts in the market, interest in sustainable
agriculture, resilient to climate change, regulatory requirements, market demand and rate of
investment (Table18). Different by products are generated from insect mediated composting
which include larvae, oil, frass, chitin and protein powder exclusively from BSFL (Table19).
Table 20 revealed the cost of insect mediated composting affected by several factors such as
labour cost, infrastructure cost, feed stock cost, equipment cost marketing and distribution cost.
Equipment cost includes the cost of containers or bins for the compost, Labour cost include the
size of operation and number of people involved in managing the compost. The cost of insect
mediated compost based on quality revealed that high quality red runner coackroach compost is
very expensive i.e 300 rupees per kg while high quality compost for dung beetles is 150 Rs per
Kg (Table 21). Any insect based compost cost can be estimated based on the amount of feed
stock requirement and amount of labour required, cost of equipment and infrastructure (Scale of
operation) : Cost of feed stock such as food waste, agricultural waste and yard waste and
transportation cost (Table 22).