Damage+to+honey+bee+hosts

=How does the //Varroa// mite harm the honey bee? = A bee pupa (shown below) is known to lose weight in proportion to the number of //Varroa// mites that are attacking it (Elizabeth Macarthur Agriculture Institute 2003). There is an average body weight loss of seven percent for just one mite infestation ( Rosenkranz et al. 2010 ).There are then consequences for this bee because it develops into an adult and flies and forages at an earlier stage, and has a shorter life span and a weaker immune systemthan unaffected bees (Elizabeth Macarthur Agriculture Institute 2003; Le Conte & Navajas 2008; Rosenkranz et al. 2010 ).

 This is an example of the effects that //Varroa// mite infestations have on bee pupae. Source: Agricultural Research 2005.  . ﻿  Not only does the mite affect the morphology of the bee, it can also affect its cognitive functions (Navajas et al. 2008). Cognitive functions involve the process of learning, information storage and retrieval, as well as other mental processes. In some cases, it is only the cognitive functions of a bee that are affected by the mite (Navajas et al. 2008). These bees ‘display a decrease in learning capability, prolonged absences from the nest and a lower rate of return to the colony’ (Navajas et al. 2008). The reason this occurs is not yet understood, but there are several different suggestions. Scientific research has revealed, among many other effects, a down-regulation of the enzyme tyramine hydroxylase, which is responsible for stimulating the nervous system ‘and has many functions in the brain, including important roles in neural development, behavior [sic] and cognition, motor activity, motivation and learning’ (Navajas et al. 2008). Enzymes are biological catalysts and aid in speeding up specific chemical reactions that occur in many organisms ([]). The foraging bees, which are the most mature bees in the colony, were also found to have the greatest difficulty in learning and orientating while flying (Navajas et al. 2008). <span style="display: block; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none; text-align: justify;"> . <span style="display: block; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none; text-align: justify;"><span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt;">media type="custom" key="7406113"  <span style="display: block; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none; text-align: justify;"><span style="font-family: 'Arial Narrow','sans-serif'; font-size: 12pt;">This video gives insight into how complex the process is for a bee to fly and how any changes in a bee's cognitive functions could be life threatening. <span style="display: block; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none; text-align: justify;"> . <span style="display: block; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none; text-align: justify;"> ©Kirsty Pearson 2010 <span style="display: block; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none; text-align: justify;"><span style="display: block; font-family: Tahoma,Geneva,sans-serif; font-size: 80%; line-height: 115%; margin: 0cm 0cm 10pt; text-align: center;">Video courtesy of [|www.youtube.com]