Sap transport proteins. Recent evidence indicates that mobile proteins and RNA are part of the plant's long-distance communication signaling system. Evidence also exists for the directed transport and sorting of macromolecules as they pass through plasmodesmata." A large number of insects of the order Hemiptera (the half-wings), feed directly on phloem sap, and make it the primary component of their diet. Phloem sap is "nutrient-rich compared with many other plant products and generally lacking in toxins and feeding deterrents, [yet] it is consumed as the dominant or sole diet by a very restricted range of animals". This apparent paradox is explained
Xylosandrus compactus and "Melia azedarach". It is particularly damaging in tree nurseries, killing seedlings and young saplings. A study in Uganda's shaded robusta coffee systems, tree species suppressing "X. compactus" infestation characteristically exuded copious sap regardless of any stress. Therefore, the presence or absence of copious sap exuding from trees upon injury likely differentiates "X. compactus" hosts from non-hosts. In Florida, where "X. compactus" has been introduced, the life cycle is completed in about twenty-eight days. Like other ambrosia beetles, the adult female carries a fungal symbiont, in this case "Fusarium solani". This fungus attacks the xylem tissue of the plant host,