  We report complex magnetotransport patterns of the $\nu=1$ integer quantum
Hall state in a GaAs/AlGaAs sample from the newest generation with a record
high electron mobility. The reentrant integer quantum Hall effect in the flanks
of the $\nu=1$ plateau indicates the formation of the integer quantum Hall
Wigner solid, a collective insulator. Moreover, at a fixed filling factor, the
longitudinal resistance versus temperature in the region of the integer quantum
Hall Wigner solid exhibits a sharp peak. Such sharp peaks in the longitudinal
resistance versus temperature so far were only detected for bubble phases
forming in high Landau levels but were absent in the region of the Anderson
insulator. We suggest that in samples of sufficiently low disorder sharp peaks
in the longitudinal resistance versus temperature traces are universal
transport signatures of all isotropic electron solids that form in the flanks
of integer quantum Hall plateaus. We discuss possible origins of these sharp
resistance peaks and we draw a stability diagram for the insulating phases in
the $\nu$-$T$ phase space.
