by Ayushi Bandyopadhyay and Saswat Tripathy
After metabolization of food, the essential nutrients are absorbed, leaving behind the waste products as a fecal matter which needs to be rejected. But imagine the waste piling up day after day; with billions of animals living on earth for centuries, imagine the number of feces our planet would have accumulated, along with the catastrophic diseases and dangerous gases in the atmosphere. Looks scary right! Well, to you and me it’s the grossest thing, but to our subject of interest, it’s all that it needs.
Dung beetles are seen lying on their back, struggling to get back up. They are considered as small entertaining creatures with their creepy-crawly walk stumbling on the ground. Hardly anyone gives importance to its work, i.e. rolling the dung ball. Dung beetles have ancient historical importance in Egyptian hieroglyphs. They were worshipped as “Scarabs” which indicates the family Scarabaedae, believed to roll the sun around the earth and every morning a new sun is reborn. These organisms are the size of a toenail, having a hard body structure, armoured with colourful coverings. Unlike their hard and cold body they love to stay moist, and the dung of higher vertebrates especially herbivores provides the exact environment due to its composition. It is highly nutritious for the beetles.
Strategy for utilization of dung
Dung beetles have their own strategy of utilizing the dung. Few live in the dung (dwellers), few bury the dung (burrowers), and few roll it (rollers), and there are some that do all. These tiny organisms have strong muscles that help them bury and roll up more dung than their body weight. They are great sculptors too, they make a ball out of the dung using their chisel-shaped head to carve out small dung fragments and roll them into a ball with help of their forelimbs. Males with better sculptures have more chances of mating. However, they have to be strong and strategic enough to defend the treasure on the battleground.
The next stage is to bury its treasure in the nearest perfect spot in order to protect the food and itself from the enemies. They roll the ball, either by walking upside down; rolling with hind limbs and using the forelimbs to walk, support, and defend, or by pulling the ball with hind limbs, to the nest. Upside down walk has a disadvantage for the beetles that they go through a variety of terrain which may cause diversion but they avoid the problem by using celestial cues and polarized lights of the sky to get into the direction of their nest. They burrow under the soil surface to make nests and hide the ball after which they mate underground and the female lays eggs on the ball. The grubs eat from the dung ball, grow in size, and metamorphose into adults to continue the low profile job. All of these activities have an important ecological impact on the environment and the local habitat.
Image 1: Pictorial representation of dung beetle activities. Picture credit: Ayushi Bandyopadhyay
- Decomposition: Dung beetles break down the dung into smaller fragments helping the microbes to break it down further and dissociate in the soil. This helps in soil enrichment, providing a habitat for earthworms and other beneficial microbes. Burying the dung ball underground in the nest also fastens the rate of decomposition.
- Seed dispersion: The dung of herbivores contains undigested seeds of the vegetation they eat. These beetles help in protecting the seed from predation and transport the seed from one place to another in the process of rolling. While burrowing the dung ball they assist in plant growth.
- Nutrient cycling and building soil structure: In the process of burrowing, numerous beetles dig millions of holes in the ground perforating the soil, creating channels that connect underneath, leading to multiple soil benefits like nutrient cycling, groundwater recharge, and soil aeration.
- Check the growth of harmful organisms: Dung beetles digest and destroy the eggs and larvae of disease-causing worms, bacteria, flies, and other pathogens present in the dung, thus keeping a check on their growth and spread.
- Bio-indicators: The application of chemical fertilizers in the crops disrupts the quality of dung on which the dung beetles are fully dependent. Being a part of the food chain, birds and some mammals feed on the beetles resulting in the possibility of biomagnification of those chemicals. Thus, dung beetles act as indicators in this aspect.
Image 2: Burrower beetle with chisel-shaped head. Image credit: Saswat Tripathy
Image 3: Burrower beetle with a horn on the head. Image credit: Saswat Tripathy
Image 4: Roller beetle with dung ball. Image credit: Rajesh Lenka, ZSI, Kolkata
Measures for dung beetle conservation
- Loss of biodiversity is indicated primarily due to habitat loss and degradation. Dung beetles inhabit a wide array of habitats. Protection of those habitats by keeping away anthropogenic disturbances and developmental activities will have a great influence on the dung beetles.
- Under the umbrella effect, conservation of large herbivore mammals will ultimately provide protection to the dung beetles as per their dung dependency. For example the African elephant; Protecting the elephants ultimately protects the grasslands along with the dwellers specific to that habitat like zebras, rhinos, which brings the attention of the dung beetles into the umbrella effect.
- Organic farming practices will be the best countermeasure against agrochemicals and pesticides, where bio-fertilizers and organic compost are utilized for good quality of yield and healthy soil atmosphere which will result in healthy vegetation on which the herbivores and the dung beetles depend down the line.
Whether it is the large animals or smaller ones or the smallest, everyone has an important role in the ecosystem. Dung beetles play an integrative role for the ecosystem health exhibiting indirect benefits to plants, other animals, and humans. Thus, it is important to provide amenities for the survival of these critters, so that it will not only improve the ecosphere but also human culture will get a better form which will cultivate further ideas for the conservation of biodiversity.
Ayushi Bandyopadhyay, MSc final year, Department of Biodiversity and Conservation of Natural Resources, Central University of Odisha, Koraput.
Saswat Tripathy, M. Phil research scholar, Department of Biodiversity and Conservation of Natural Resources, Central University of Odisha, Koraput.