1. Introduction
2. Data
2.1. Observations
2.2. Galaxy sample
2.3. Stellar masses
3. Dwarf galaxy distribution
3.2. Radial distribution of dwarf galaxies
4. Luminosity function
4.1. In the whole cluster
4.2. Luminosity function in radial bins
5. Dwarf galaxy structure
5.1. Structural scaling relations
5.2. Axis-ratios
5.3. Effects of the environment on the dwarf galaxy structure
6. Colors of the dwarf galaxies
6.1. Color-magnitude relation
6.2. Dependence on the environment
7. Discussion
7.2. What causes the cluster-centric relations?
7.3. Effects of environmental processes
7.4. Are the dwarf galaxies in the Virgo and Fornax clusters different?
8. Summary and conclusions