  We study the game-theoretic task of selecting mobile agents to deliver
multiple items on a network. An instance is given by $m$ messages (physical
objects) which have to be transported between specified source-target pairs in
a weighted undirected graph, and $k$ mobile heterogeneous agents, each being
able to transport one message at a time. Following a recent model by
[B\"artschi et al. 2016], each agent $i$ consumes energy proportional to the
distance it travels in the graph, where the different rates of energy
consumption are given by weight factors $w_i$. We are interested in optimizing
or approximating the total energy consumption over all selected agents.
  Unlike previous research, we assume the weights to be private values known
only to the respective agents. We present three different mechanisms which
select, route and pay the agents in a truthful way that guarantees voluntary
participation of the agents, while approximating the optimum energy consumption
by a constant factor. To this end we analyze a previous structural result and
an approximation algorithm given by [B\"artschi et al. 2017]. Finally, we show
that for some instances in the case of a single package, the sum of the
payments can be bounded in terms of the optimum.
