<p>Honeybees are very important pollinators, and are the primary pollinator for many plants. Without honeybees, these plants have greatly reduced fertility. In North America and Australia, where there are no native bee species with large colonies, honeybees can have especially strong effects on native flowers, and on other pollinators such as solitary bee species. Honeybees ability to recruit fellow workers by “dancing” allows them to be more efficient than other pollinators at exploiting patches of flowers. This can create strong impacts on their competitors, especially solitary bees.</p>  <p>Like all social insects, honeybees are hosts to a variety of parasites, commensal organisms, and pathogenic microbes. Some of these can be serious problems for apiculture, and have been studied intensively. At least 18 types of viruses have been found to cause disease in bees, including Sacbrood disease. Several of them (but not sacbrood virus) are associated with parasitic mites. Bacteria infect bees, notably <span class="taxon">Bacillus larvae</span>, agent of American Foulbrood disease, and <span class="taxon">Melissococcus pluton</span>, agent of European Foulbrood. Fungi grow in bee hives, and <span class="taxon">Ascosphaera apis</span> can cause Chalkbrood disease. One of the most common diseases in domesticated hives is Nosema disease, caused by a protozoan, <span class="taxon">Nosema apis</span>. An amoeba, <span class="taxon">Malphigamoeba mellificae</span>, also causes disease in honeybees.</p>  <p>In recent decades, two mite species have spread through domesticated and feral honeybee populations around the world. <span class="taxon">Acarapis woodi</span> is a small mite species that lives in the tracheae of adult bees and feeds on bee hemolymph. It was first discovered in Europe, but its origin is unknown. Infestations of these mites weaken bees, and in cold climates, whole colonies may fail when the bees are confined in the hive during the winter. A much worse threat is <span class="taxon">Varroa destructor</span>. This might evolved on an Asian honeybee, <span class="taxon">Apis cerana</span>, but switched on to <span class="taxon"><em>Apis mellifera</em></span> colonies that were set up in east Asia. It has since spread all around the world, except Australia. Juvenile mites feed on bee larvae and pupae, and adult female mites feed and disperse on adult workers. This mite is known to spread several viruses as well. Infestations of <em>V. destructor</em> often wipe out colonies. Nearly all the feral, untended honeybee colonies in North American are believed to have been wiped out by mite infestations, along with a large proportion of domesticated colonies. Other mite species are known from honeybee colonies, but they are not considered harmful.</p>  <p>Another commensal or parasitic species is <span class="taxon"><em>Braula coeca</em></span>, the bee louse. Despite the common name, this is actually a wingless fly, that apparently feeds by intercepting food being transferred from one bee to another.</p>  <p>Beetles in the genera <span class="taxon">Hylostoma</span> and <span class="taxon">Aethina</span> are found in African honeybee nests, where they seem to do little harm. However, the "small hive beetle", <span class="taxon">Aethina tumida</span>, has become a significant problem in European and North American hives. The larvae eat all the contents of comb: honey, pollen, and bee eggs and larvae.<span> (Adjare, 1990; Roubik, 1989; Sammataro and Avitabile, 1998)</span></p>  <p><strong>Ecosystem Impact: </strong>Pollinates; Keystone species</p>