View Full Version : Food collecting behavior of dung beetles (the rollers)

Arun Acharjee
21-09-2016, 07:54 PM
Part: 1
Dung beetle has fascinated humans for thousands of years- including the Egyptians who incorrectly believed that the beetles reproduced from male only. But their observation that the beetles’ ball rolling is influenced by the sun is accurate and could be the first recorded accounts of animal behavior. [1]

My experience on these two beetles from Scarabaeinae subfamily under the family Scarabaeidae shows nothing exception of the behavior studied approximately 5,500 years past. Almost, all the beetles under this particular subfamily are known to feed on dung and thereby is collectively called Dung Beetles. Now, the question comes why they practice such vulgar habit. My field study on their food collecting behavior has not any clues to the right answers. Though, when I start finding causes behind their ball rolling I come across many astounding facts. A little point behind their feeding on poops would not be incoherent. Dung beetles like feeding more on poops of the herbivorous animals than that of the carnivorous animals because most of the herbivorous poops are fertile with many undigested ingredients which would appease the hunger of these poor creatures [4]. From my personal experience I find rabbits feeding on their own poops directly from/out of their anus. Though the excrements of the omnivores may be more palatable [4].

Not all the members of Scarabaeinae use to roll their food items. A great number of them use to make tunnel directly beneath the dung source and make their nest underground (called the ‘Tunnelers’) and some of them like the dung source as its domicile (called the ‘Dwellers’). The image I attach here show another kind of dung beetle whose common English name is influenced with their food collecting behavior of rolling poops (‘food’ from their perspective) to their favorite place; these are the ‘Rollers’.

When I encountered them rolling under a mid-day sun I became spellbound thinking how these little creatures study nature to decrease their labor in carrying something by giving a round shape. In student life, like as all, I read how ancient people study a round stone fall fast and deep than those not round in shape or the rolling of round logs from hilltop and how those lessons made them invent wheels which led the civilization many steps ahead towards modernization. If we take these beetles activity in account from their appearance in this planet (though many anatomical and behavioral changes would have followed) it might be possible to human beings studying their food rolling patterns as a practical instance of the benefits of round shape in the field of transportation behind the grand invention of wheels dates almost back to the late Neolithic age[3], at about 10,000 years past, whereas the evolution of dung beetles occurs at about 115 to 130 million years ago in the Lower Cretaceous period[2].

This is not the only similarity found between these rollers and the human beings. Carrying a huge dung ball is not always an easy task. To decrease labor, alike giving it a round shape, they also use to follow almost straight line from the source of the dung to their favorite place and thereby travel possible shortest distance. To measure the distance by a planned map or straight line is not an easy work for such little fellows. To ensure it, as the ancient Egyptians discovered, they study celestial bodies like as the sun (in day) and the moon (at night) and make them their compasses. Even some of them use Milky Way in doing so [1]. The instances of studying such natural bodies to get direction may not exceptional in nature but it makes me greatly astonished when I recollect my habit of getting direction studying my watch and the position of the sun many a time at the time of field-work and thereby copy a part of their tact born years ago in an unconscious mind.

I found them midway and the process of rolling or transportation last roughly for just forty seconds within when they covered approximately eighty centimeters of distance. At the near end of their destination I found them lifting the ball against a plant-part. For doing so- making a ball of dung which is sometimes heavier than their own weight- rolling that and lifting- they have evolved with strong legs.

At first I found them comparatively on a fresh and clean ground rolling their ball. Almost in one second I noticed them covering a distance of approximately two centimeters.

Arun Acharjee
21-09-2016, 08:03 PM
They are lifting the ball against a plant-part. They were just busy in reaching their targeted area and to do that in possible short time and were not found to look for alternative way to reach that place. An alternative way to reach the area to avoid that job of lifting had no scope too. So it may be said that they were well informed of that place previously.

Arun Acharjee
21-09-2016, 08:08 PM
Having reached their favorite destination I found one of them became busy, without having a bit of rest, in making a tunnel from the surface of the land. Its hurriedness surely indicates its stamina level and dedication for duty. Meanwhile, another one was taking care of the ball by clasping it from the beginning to the end of the process of digging the tunnel. When it was done both of them helped the ball went therein.

Start digging the tunnel in a hurry. Another one is guarding the ball.

Arun Acharjee
21-09-2016, 08:12 PM
The beetle was lifting the loose mud upwards to make a clean tunnel. The job of digging was not complete still then.

Arun Acharjee
21-09-2016, 08:15 PM
The tunnel was almost done. The beetle was nearly disappearing in that empty tunnel. Another one was still guarding the ball.

Arun Acharjee
21-09-2016, 08:18 PM
When the job of digging was complete it came out of that and both of them helped the ball went into the tunnel.

Arun Acharjee
21-09-2016, 08:25 PM
That beetle which dig the tunnel remained into the tunnel again while that one who was once guarding the ball tried to push the ball into the tunnel with its best from different angles. I don't know what was the beetle, that went downward again, doing then. But their respect to their duty would say it was doing nothing but making passage for the dung ball went smooth therein (as I think).

Arun Acharjee
21-09-2016, 08:29 PM
The beetle that remained always out of the tunnel was then at a little distance when the dung ball is almost set to the tunnel. Another one remained into the tunnel.

Arun Acharjee
21-09-2016, 08:31 PM
The location for the burying of the dung is significant too. When I first discovered them they were driving their ball on a relatively fresh and clean land. They carried that to, and buried too, the land congested with grasses, leaves etc. Studying from a common man’s perspective I think that is for securing their possession from any unexpected threat. They are also known for laying eggs on/into the collected poop. Sometimes, the male alone carries the dung, buries that and comes back to the opening of the tunnel to make phenomenal signal to the nearby female for mating and laying eggs therein [1]. So, the point of security behind such choice of land cannot be discarded as almost all the lives on this planet aware of the security for their own future generations. I neither know the sex(es) of these dung beetles I found in the field nor what they do with that poop ball after burying but surely can say that these poor fellows possess a good many attitudes to influence a common man like me.

Special thanks to:
Surajit Bhadra Roy and Samrat Sarkar to inspire me to write this, and few internet sources to provide additional information.
Sources of additional information (links):
[1]. http://theconversation.com/five-things-dung-beetles-do-with-a-piece-of-poo-47367
[2]. http://phys.org/news/2016-05-evidence-dung-beetle-evolution-dinosaurs.html
[3]. https://en.m.wikipedia.org/wiki/Wheel
[4]. http://insects.about.com/od/beetles/a/10-Fascinating-Facts-About-Dung-Beetles.htm

(The second link I provide here is with a little change. Firstly, it came to me as http://m.phys.org/news/2016-05-evidence-dung-beetle-evolution-dinosaurs.html . Thereafter, when I click on this to make sure again I found message knowing me that there is no such page. I search again in Google with the keywords ‘dung beetle origin’ and I found this link as mentioned in point [2]. I don’t know whether it would change again or not. Also, I’m not sure about the contents remain same with the previous ones which I followed at the time of writing this.)