Is it true that dual SIM phones last less than single SIM phones?

[xperia2995]

I read some articles which got me thinking. I have the following two questions.

Qn 1) They stated that dual SIM phones last less due to the different hardware organization required for holding two SIM slots
Can this be true?

Qn 2) Dual SIMs use more battery because both networks use power to capture signals.
Seems true, but what happens to consumption when only one SIM is inserted in a dual SIM phone?

 

[AndroidProf]

I think manufacturers make these phones with such problems in mind. So if that is the case, then, that would mean its would consume less power...just a thought; if a vehicle is made to carry two vehicles, wouldn't it last longer if it only carried one or half its load capacity?