%0 Journal Article
%T An Insight into the Sialomes of Bloodsucking Heteroptera
%A Jos¨¦ M. C. Ribeiro
%A Teresa C. Assump£¿£¿o
%A Ivo M. B. Francischetti
%J Psyche
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/470436
%X Saliva of bloodsucking arthropods contains dozens or hundreds of proteins that affect their hosts' mechanisms against blood loss (hemostasis) and inflammation. Because acquisition of the hematophagous habit evolved independently in several arthropod orders and at least twice within the true bugs, there is a convergent evolutionary scenario that creates a different salivary potion for each organism evolving independently to hematophagy. Additionally, the immune pressure posed by their hosts creates additional evolutionary pressure on the genes coding for salivary proteins, including gene obsolescence, which opens the niche for coopting new genes (exaptation). In the past 10 years, several salivary transcriptomes from bloodsucking Heteroptera and one from a seed-feeding Pentatomorpha were produced, allowing insight into the salivary potion of these organisms and the evolutionary pathway to the blood-feeding mode. 1. Introduction The order Hemiptera (bugs) comprises hemimetabolous insects having in common tubular mouthparts specialized for sucking liquid diets. The diet of Hemiptera is varied, the majority feeding on plants by either tapping the vessels conducting sap or by lacerating and flushing tissues such as leaves or seeds. Within the suborder Heteroptera (true bugs), predatory feeding (with killing of the victim) also occurs, mostly targeting other insects but also including small vertebrates such as giant water bugs and toad bugs, as well as blood or hemolymph feeding (without killing the victim) from vertebrate and invertebrate animals. The mouthparts are not only important for channeling the liquid meal but are extremely important mechanically in finding the proper spot for meal suction [1]. Saliva is produced, sometimes copiously, during the probing phase (the time between mouthpart contact with the food substrate and the commencement of the meal) and throughout the meal [31, 32]. This saliva is ejected at the tip of the maxillae by the salivary channel, which is built in between the interdigitations of the two plates that form the maxillae [33]. Saliva helps probing and feeding physically by liquefying insoluble or viscous tissues or by helping to seal the feeding site in sap suckers, were the phloem is under very high pressure [34]. Saliva has a biochemical role in aiding digestion of the meal, just as we have amylase in our own saliva; most remarkably, predacious bugs inject a highly hydrolytic cocktail into their victims that is digested while the prey is held by the predator, which can then later suck the liquefied victim and discard it as
%U http://www.hindawi.com/journals/psyche/2012/470436/