Study maps indigenous communities' use of 75 edible beetle species

A study by entomologists at the Ashoka Trust for Research in Ecology and the Environment (ATREE), Bengaluru, has documented 24 beetle species in Northeast India that are reported as edible for the first time globally and five with previously undocumented records of edible use in India. In all, the study documented 75 beetle species used for culinary purposes by indigenous communities in Northeast India.

The study, published in npj Entomology, a Nature Group journal, highlights the region's traditional knowledge of edible insects and the need to conserve both the species and their natural habitats. The study was led by Priyadarsanan Dharma Rajan and included researchers Swapnil S. Boyane, Aavika Dhanda, A.P. Ranjith, and T. Shantibala.

The study involved interviews with 162 people from nine indigenous communities across Arunachal Pradesh, Manipur, Mizoram, and Nagaland. The researchers collected and scientifically identified beetles, and documented harvesting seasons and methods, culinary practices, cultural beliefs, and medicinal uses.

According to the researchers, the beetles were collected from diverse habitats, including forests, bamboo clusters, paddy fields, and wetlands. Depending on the species and its life stage, they were consumed after boiling, roasting, or frying, sometimes with bamboo shoots and local spices. The researchers found that many species were specific to individual communities and had relatively little overlap in their traditional food practices.

Protein content varies across species

Nutritional analysis of four beetle species revealed substantial differences in their composition. Protein content ranged from 22.43% to 61% of dry weight. The coconut pest Oryctes rhinoceros and weevils belonging to the genus Cyrtotrachelus recorded the highest protein values, ranging from 46.44% to 61%. Aquatic beetles had lower protein content, ranging from 22.43% to 23.23%.

The researchers also found differences in lipid, moisture, ash, energy, and mineral content. Pointing to these differences, the researchers stressed that the nutritional value of edible beetles should not be generalised and that claims should be tied to particular species and samples.

The study notes that insects are being explored as alternative sources of protein amid concerns over the environmental impact of conventional livestock production. It points out that poultry and cattle production account for nearly 14.5% of global greenhouse gas emissions. In addition, livestock production contributes to land degradation and air and water pollution. "Insect farming can require less land and water and generate fewer greenhouse gas emissions," the study notes.

Habitat loss threatens beetle populations

The researchers flagged concerns over declining populations of wood-boring beetles. About 79% of the harvesters interviewed reported a decline in these beetles over the previous decade. Among those who reported declines, 63% attributed them to deforestation and habitat loss, while others cited overharvesting driven by market demand.

The paper said the researchers observed trees being cut down to extract the larvae of wood-boring beetles. The larvae are considered a delicacy in the region. The researchers said harvesting the insects serves as a natural form of pest control, but large-scale extraction could affect forest health if not managed carefully.

The researchers recommend protecting natural habitats, adopting harvesting practices suited to specific seasons and life stages, exploring mass rearing, and involving indigenous communities in decisions on sustainable use.

The paper also stresses the importance of documenting traditional knowledge passed down orally through generations.