Editing Alkane (section)

===Ecological relations===
[[Image:Ophrys sphegodes flower.jpg|thumb|upright|right|Early spider orchid (''[[Ophrys sphegodes]]'')]]
One example, in which both plant and animal alkanes play a role, is the ecological relationship between the [[sand bee]] (''[[Andrena nigroaenea]]'') and the [[early spider orchid]] (''[[Ophrys sphegodes]]''); the latter is dependent for [[pollination]] on the former. Sand bees use pheromones in order to identify a mate; in the case of ''A. nigroaenea'', the females emit a mixture of [[tricosane]] (C<sub>23</sub>H<sub>48</sub>), [[pentacosane]] (C<sub>25</sub>H<sub>52</sub>) and [[heptacosane]] (C<sub>27</sub>H<sub>56</sub>) in the ratio 3:3:1, and males are attracted by specifically this odor. The orchid takes advantage of this mating arrangement to get the male bee to collect and disseminate its pollen; parts of its flower not only resemble the appearance of sand bees but also produce large quantities of the three alkanes in the same ratio as female sand bees. As a result, numerous males are lured to the blooms and attempt to copulate with their imaginary partner: although this endeavor is not crowned with success for the bee, it allows the orchid to transfer its pollen,
which will be dispersed after the departure of the frustrated male to other blooms.