Emery's Rule
Encyclopedia
In 1909, the entomologist Carlo Emery
noted that social parasites among insects (e.g., cleptoparasites) tend to be parasites of species or genera to which they are closely related. Over the years, this pattern has been recognized in many additional cases, and generalized to what is now known as Emery's Rule. The pattern is best known for various taxa of Hymenoptera
, but also in members of other kingdoms such as fungi, red algae
, and mistletoe
. The significance and general relevance of this pattern is still a matter of some debate, as a great many exceptions exist, though a common explanation for the phenomenon when it occurs is that the parasites may have started as facultative parasites within the host species itself (such forms of intraspecific parasitism are well-known, even in some subspecies of honeybees ), but later became reproductively isolated and split off from the ancestral species, a form of sympatric speciation
.
Carlo Emery
Carlo Emery was an Italian entomologist.Born in Naples, Carlo Emery was professor of Zoology at the University of Bologna. He later worked in Geneva...
noted that social parasites among insects (e.g., cleptoparasites) tend to be parasites of species or genera to which they are closely related. Over the years, this pattern has been recognized in many additional cases, and generalized to what is now known as Emery's Rule. The pattern is best known for various taxa of Hymenoptera
Hymenoptera
Hymenoptera is one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. There are over 130,000 recognized species, with many more remaining to be described. The name refers to the heavy wings of the insects, and is derived from the Ancient Greek ὑμήν : membrane and...
, but also in members of other kingdoms such as fungi, red algae
Red algae
The red algae are one of the oldest groups of eukaryotic algae, and also one of the largest, with about 5,000–6,000 species of mostly multicellular, marine algae, including many notable seaweeds...
, and mistletoe
Mistletoe
Mistletoe is the common name for obligate hemi-parasitic plants in several families in the order Santalales. The plants in question grow attached to and within the branches of a tree or shrub.-Mistletoe in the genus Viscum:...
. The significance and general relevance of this pattern is still a matter of some debate, as a great many exceptions exist, though a common explanation for the phenomenon when it occurs is that the parasites may have started as facultative parasites within the host species itself (such forms of intraspecific parasitism are well-known, even in some subspecies of honeybees ), but later became reproductively isolated and split off from the ancestral species, a form of sympatric speciation
Sympatric speciation
Sympatric speciation is the process through which new species evolve from a single ancestral species while inhabiting the same geographic region. In evolutionary biology and biogeography, sympatric and sympatry are terms referring to organisms whose ranges overlap or are even identical, so that...
.