Before revision:  From previous results, we may speculate about the fact that chemotactic cells , in many cases, can avoid obstacles by simply following the altered chemical gradient : social interactions seem to be sufficient to guarantee the aggregation of the whole colony past numerous obstacles . It is then unlikely that cells have developed special mechanisms to cope with the presence of topological perturbation sources. Nevertheless, we suggest that further studies can provide better understanding and that, in order to gain deeper knowledge, mechanical models should be coupled with phenomenological, system-oriented ones .
After revision:  From previous results, we may speculate about the fact that chemotactic cells , in many cases, can avoid obstacles by simply following the altered chemical gradient : social interactions seem to be sufficient to guarantee the aggregation of the whole colony past numerous obstacles .