Hemiptera plant. Phloem sap, which has a higher concentration of sugars and nitrogen, is under positive pressure unlike the more dilute xylem sap. Most of the Sternorrhyncha and a number of Auchenorrhynchan groups feed on phloem. Phloem feeding is common in the Fulgoromorpha, most Cicadellidae and in the Heteroptera. The Typhlocybine Cicadellids specialize in feeding on non-vascular mesophyll tissue of leaves, which is more nutritious than the leaf epidermis. Most Heteroptera also feed on mesophyll tissue where they are more likely to encounter defensive secondary plant metabolites which often leads to the evolution of host specificity. Obligate xylem feeding is a
Sugary drink tax Michael Bloomberg of orchestrating the controversial bill from overseas. In late October 2013, the Mexican Senate approved a 1 MXN per litre tax (around 0.08 USD) on sodas, along with a 5% tax on junk food. Research has shown that Mexico's sugary drinks tax reduced soft drink consumption. According to a 2016 study published in "BMJ", annual sales of sodas in Mexico declined 6% in 2014 after the introduction of the soda tax. Monthly sales figures for December 2014 were down 12% on the previous two years. Households with the fewest resources had an average reduction in purchases of 9%