Is it dead workers or food ?

Large food items may be cut up and moved, bit by bit, to the nest. Large food items that can't be cut up quickly and that are buried remain available to the colony. In the latter case, part of the colony might be moved to the prey item. It either case, the food it protected from competitors.

They do not bury their food. They carry the food to their nest (colony) which is underground in the case of Pheidole megacephala. As James said, they can break their food into smaller pieces if the entrance is small.

Je ne suis pas d'accord. Pour certaines espèces, il ne s'agit pas d'un simple apport vers le nid, mais -comme il a dit Azwandi- c'est un vrai enterrement. A mon avis, c'est une question de comportement alimentaire sociale . Même en absence de concurrence (élevage au laboratoire), les fourmis continuent à enterrer leurs nourriture (et surtout leurs proies fraîches). C'est en fait, une méthode pour de stockage de resserves. Les fourmis granivores (Messor, goniomma ...) stockent des Kgs de graines, quelques fourmis prédatrice pourraient même enterrer de la chair.

Question might be if they did this to protect the carcass or did it accidentally, e.g. when enlarging the colony...anyway they might prey more on the scavengers in the carcass (dipteran larvae etc) than being a scavenger itself.

Thank for the answers. I agree with Peter. In my observation, the ants are capable to delay Diptera arrival, prevent oviposition and being a proficient predator to fly eggs. Below is the picture. Any other suggestions? Its is still remains a question weather its a feeding behavior or as a food protection strategy.

If the carcass serves as a source of food in the form of fly eggs (and I presume larvae too) burying the carcass would seem to be counterproductive. This huge mass of food has a very short shelf-life and so I'd be thinking about whether the ants are displaying any selectivity about what particular bits they haul away. It looks like a lovely little experiment to set up with shelf-life and foraging intensity being the variables.

Carcases can provide all possibilities, since directly provide food (meat and fat), and can offer prey, such as eggs and larvae of flies. I believe the two are more reasonable possibility.