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* FTSEurofirst 300 down 0.4 pct, Euro STOXX 50 down 0.5 pct
* Vodafone rises after strong results, Vallourec drops
* Portuguese stocks underperform on political uncertainty
By Danilo Masoni
MILAN, Nov 10 (Reuters) - European shares were lower onTuesday for a second straight day as losses among commoditystocks and political uncertainty in Portugal weighed, whileVodafone shone in an otherwise mixed picture forcorporate earnings.
The pan-European FTSEurofirst 300 was down 0.4percent, giving up initial gains, and the euro zone's blue-chipEuro STOXX 50 index was down 0.5 percent.
Shares had opened higher on the back of a weaker euro, whichmakes investment in the region more attractive, but pared gainsas commodities stocks extended falls and U.S. futures pointed toa lower open at Wall Street.
The European mining index was the top sectoralfaller with a drop of 1.35 percent, as London copper pricesmoved closer to a six-year low on Tuesday amid a firmer dollarand prolonged economic weakness in top metals consumer China.
Construction sector stocks were also weaker, withFrench construction and concessions company Eiffage falling more than 4 percent after weak domestic business weighedon its quarterly results.
Roberto Lottici, a fund manager at Italy's Ifigest, saidexpectations of central bank support were providing a floor forEuropean equities but recommended investors pick out individualstocks and consolidate gains as the year end approaches.
Vallourec fell more than 10 percent afterreporting a third-quarter loss against a backdrop of fallingdemand from its oil and gas customers and said it did not expectmarket conditions to improve in the short-term.
But Vodafone rose almost 5 percent after the Britishphone group reported a better-than-expected acceleration insecond-quarter revenue growth, helping it nudge its annualexpectations towards the top of its guidance.
Dialog Semiconductor was another bright spot,rising 5 percent, after activist hedge fund Elliott disclosed a2.9 pct stake in the German chipmaker and opposed theacquisition of U.S. peer Atmel.
Portugal's PSI 20 index fell 1.9 percent asleftwing parties looked set to oust a minority centre-rightgovernment on Tuesday in a parliamentary vote, part of a driveto set up their own Socialist-led administration they hope willput an end to years of austerity.
"Events unfolding in Portugal are especially closely watchedbecause their much larger neighbour Spain will also be holdingelections in late December which depending on the outcome couldpush the Eurozone back into a crisis," said Peregrine & Blacksales trader Markus Huber. (Editing by Keith Weir)
