The European parliament has vetoed a move by member states and the European commission to weaken EU rules protecting bee colonies from toxic pesticides. 

MEPs blocked revised legislation that was said to ignore the risk to bee larvae from long-term exposure to chemicals, known as chronic toxicity. 

The MEPs instead argued a guidance document produced by the European Food Safety Authority (EFSA) in 2013 should be fully implemented. 

The guidance seeks both to protect bees from adverse effects from a single exposure or multiple exposures over a short period of time, known as acute toxicity, and long-term exposure. 

Sixteen member states, which have not been publicly named, lobbied against the full implementation of the guidance before the new rules are brought to a vote in the European parliament. 

Green MEPs who led the way on the parliamentary veto claimed the new generation of systemic pesticides, which are applied via seed treatment rather than spraying, made chronic exposure particularly relevant. 

Bee populations have collapsed around the world and the use of pesticides is said to be the main cause.