NEW YORK ( TheStreet) -- Commodities-linked equities were in the red across the board Tuesday as investors sold cyclical names that had rocketed higher since the middle of last year -- many having doubled in value.The selloff touched the shares of nearly every company that plays in natural resources, from steelmakers to miners of industrial metals to chemicals producers to agricultural companies to the shipping concerns that transport those raw materials across the oceans. The plunge in cyclical names followed a severe decline in the broader equities market Thursday, with the Dow Jones Industrial Average posting triple-digit losses as investors reacted to the prospect of a continually destabilizing Middle East and what that would do to oil prices. Commodities futures led the charge into the red. The front-month copper contract was tumbling nearly 17 cents to $4.32 a pound on the Globex division of the CME, down from a record high of $4.66, set just on Feb. 15. Agricultural commodities, meanwhile, were also falling. In Chicago trading, the May corn futures contract was declining 30 cents to below $7 a bushel, extending the losses from the previous session. The reasons for the declines were several-fold. For one, many traders feel the run-up in commodities prices has created a priced-to-perfection environment in basic materials stocks. "The equities that are sensitive to commodities can't run without the underlying," said Torsten Sippel, a trader at UBS ( UBS). But, he said, "I think there are people ready to buy on the dips ... if things get back to normal." Then, of course, the contagious Middle Eastern political upheaval reached the first major oil producing nation in Libya this weekend, driving crude prices higher. Energy prices are intertwined with food prices, and inflation in both areas has raised the global specter of central banks around the world instituting inflation curbs on their economies, which would curtail growth. That's already been the case in China, where authorizes have made a series of growth-slowing moves for fear of asset bubbles and inflation. "It's almost as if some are beginning to question, in these commodity areas, how much better it can get, especially if you start to see these governments trying to rein in inflation," said Anthony Rizzuto, an equities analyst specializing in metals at Dahlman Rose, an investment firm in New York. There is no bigger central-bank prop than the U.S. Federal Reserve. The greatest uncertainty -- and the most potent fear -- remains the Fed's zero-interest rate policy and quantitative-easing programs, and what happens to the economy, and commodities markets, once that rug is pulled out from underneath. Just last week, for example, the president of the Kansas City Federal Reserve Bank, Thomas Hoenig, warned of a potential asset bubble in U.S. farmland values and commodities in general, and said that any increase in interest rates could end up bursting that bubble and slashing farmland prices by as much as a third.