Dung Beetles forgo feces for a diet of live millipedes.
The Deltochilum valgum also known as the dung beetle, has turned from scavenger to killer and is now preying on millipedes instead of the dung from other animals. This is a rare change in diet is an example of evolution for the dung beetle. The dung beetle usually feeds on other animals dung to get the bacteria from their excrement. But instead of following the trend of all other dung beetles the Deltochilum valgum rips millipedes in half and feasts on their insides. It's very competitive for the dung beetles and over 80 species are sometimes competing for the same feces.This competition is why the beetle has evolved.
Trond Larson of Princeton University was curious about the feeding habits and set up baited traps with dung, carrion(dean or rotting flesh), fruits and fungus. Over 11 months they observed 132 species and over 100,000 individuals. The D. valgum was the only species that only ate the millipedes.
Seen using infrared cameras, D. valgum's method of attack 8-millimeter-long beetle wedging its serrated head between the millipede's segments and splitting its prey's body in two. Afterward, the beetle dismantles the rest of the millipede and eats it up. D. valgum can kill prey up to 13 times its own size thanks to subtle body adaptations, including its wedged head and hind legs adapted to hold the millipede and drag it apart. These adaptations mean that there is potential for a outburst of a new predatory dung beetle species. It's a spectacular finding says biologist Armin Moczek of Indiana University, Bloomington. Millipeeds have a high proportion of fecees iside them so if the dung beetle is eating their insides it is essentially eating dung.
Posted By: Samantha DeBiasio(week 2)
Update: Feb 20,2009
Some adaptions that have formed are the head changing. Most dung beetles have broad heads to help them push and mold dung balls, D. valgum had a narrow elongated head for feeding(video) on the insides of millipeeds. They use a sharp, shield-like plate on the top of their heads like a chisel to decapitate their prey.
Some dung beetles have responded by broadening their tastes to include rotting fruit, fungi and dead animals. A couple of species will even kill queen leafcutter ants to supplement their dung-based diets. The researchers noted that monor adaptations to the beetles bodies led to large behavioral changes, like eating millipeeds. these adaptations came about possibly because of competition with relatives.
The beetles didnt dine on site they prefer dragging the dead millipeeds to another location. This is the first known case of an obligate predatory dung beetle.This was Found Jan 22,2009. this is not the first time the dung beetle has been shown to be more sophisticated, in 2006 it was found they were picky eaters by researchers in Kuwait who won an Ig Nobel Prize. Also the Dung beetle was the first animal found to use moonlight to navigate.
Posted By:Samantha DeBiasio(week 2)
posted by PWH @ 8:37 PM
6 comments
6 Comments:
Samantha,
I never would have imagined dung beetles as killers! But you gotta do what you gotta do in order to survive out there as a tiny insect competing for food. It is interesting that they are going after millipedes, which happen to have a large amount of feces inside them. But, as you point out, they are still dung beetles. I guess they must have a pretty strong sense of smell. I wonder if this change in diet will affect agriculture somehow. I’m sure getting rid of dung alone must help out with getting rid of flies and pests. But now that they are going after other living things, what will happen.
Sarah Bello
Ah, evolution at work. Have they noted any other interesting behaviors with this dung beetle as compared to others? It seems like a large gap to bridge between eating unmoving dung to actually finding, catching and devouring another entity. Perhaps there are other dung beetle variants that go after worms or other insects besides millipedes?
[Nathan Beck]
Samantha,
I love the way everything was described in this blog! It made it much more interesting with the adjectives and such. It's somewhat exciting to see evolution at its finest right before our eyes. I liked this topic. Are there any other species that are beginning to do the same as this one?
Crystal Cabral
Evolution right in front of our eyes! Do you think they will trace all the way back to find any small adaptations that the beetles may have formed? Is this the only species that this is found in recently? This was a good topic; it sure is interesting!
Alyson Paige
Samantha,
As Nathan stated, “It seems like a large gap to bridge between eating unmoving dung to actually finding, catching and devouring another entity.” In fact, this large gap may not necessarily exist. In my perspective, the competition for a single food source among 132 species of dung beetles has not caused the beetle to develop a preference for flesh. As stated in the Blog, “millipedes have a high proportion of feces inside them so if the dung beetle is eating their insides it is essentially eating dung.” The competition for a limited food source has not turned these beetles into “killer.” The dung beetle has adapted a limited, to only one species, process of getting bacteria from animal excrements. This would explain their newly adaptated ability to rip millipedes in half and feast on feces.
Saad Choudhry
Pretty neat article - is this really an example of evolution right before our eyes (fairly recently?), or has the species been around for a long time and we only recently discovered this about them? Was it always this competitive?
(Nicholas Skvir)
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