{{Short description|Genus of mayflies}} {{Use mdy dates|date=June 2019}} {{Speciesbox | image = | image_caption = | status = G4 | status_system = TNC | status_ref = <ref name=NS>{{cite NatureServe |id=2.120259 |title=''Dolania americana'' |access-date=21 January 2025}}</ref> | genus = Dolania | parent_authority = Edmunds & Traver, 1959<ref name="ITIS" /> | species = americana | authority = Edmunds & Traver, 1959<ref name="ITIS">{{cite web |url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=101523 |title=''Dolania'' Edmunds and Traver, 1959 |publisher=ITIS |accessdate=June 3, 2015}}</ref> }}
'''''Dolania''''' is a monotypic genus of mayfly in the family Behningiidae containing the single species '''''Dolania americana''''', also known as the '''American sand-burrowing mayfly'''.<ref name="BugGuide.Net">{{cite web |title=Genus Dolania – American Sand-burrowing Mayfly |website=BugGuide.Net |url=https://bugguide.net/node/view/1467046 |access-date=June 24, 2019}}</ref> It is found in the southeastern United States, as far south as Florida, and is generally uncommon.<ref name="Edmunds">{{cite book |author1=Edmunds, George F. Jr. |author1-link=George F. Edmunds (entomologist) |author2=Jensen, Steven L. |author3=Berner, Lewis |title=The Mayflies of North and Central America |url=https://books.google.com/books?id=I03mLF19rjcC&pg=RA1-PA274 |year=1976 |publisher=University of Minnesota Press |isbn=978-0-8166-5756-8 |page=274}}</ref> The adult insects emerge before dawn in early summer, mate and die within the space of about thirty minutes. The female deposits her eggs in the water and dies within five minutes of emergence. This is believed to be the shortest adult lifespan of any insect.<ref>{{cite web |url=http://entnemdept.ifas.ufl.edu/walker/ufbir/chapters/chapter_37.shtml |title=Chapter 37: Shortest reproductive life |author=Welch, Craig H. |date=April 17, 1998 |work=Book of Insect Records |publisher=University of Florida |accessdate=June 3, 2015 |url-status=dead |archiveurl=https://web.archive.org/web/20150730141612/http://entnemdept.ifas.ufl.edu/walker/ufbir/chapters/chapter_37.shtml |archivedate=July 30, 2015 }}</ref>
== Description == The adult ''Dolania americana'' has a pale brownish-purple body and membranous wings that are {{convert|10|to|13|mm|1|abbr=on}} in length. The legs of both male and females are vestigial, thin and twisted, but appear to retain some function. The cerci are longer and more robust than the terminal filaments. The penis of the male is twice as long as the genital forceps.<ref name="Edmunds" />
The body of the nymph is cylindrical with a flattened head. The antennae are on the ventral side of the head and the small mandibles do not bear any tusks. The sides of the head and the prothorax are spiny. None of the legs have claws; the front pair are palp-like and the remaining pairs are spiny and protect the gills, which are on the ventral surface of the abdomen. The abdomen is densely covered with bristles. The first abdominal segment has a pair of single gills and the other segments bear further pairs of rather smaller, bifid gills. There are three tail filaments at the tip of the abdomen.<ref name="Edmunds" />
== Distribution and habitat == ''Dolania americana'' is found in the streams and rivers of the coastal plains of the southeastern United States. The nymph burrows into the sandy riverbed and the adults appear briefly flying over the water surface.<ref name="Sweeney">{{cite journal |author1=Sweeney, Bernard W. |author2=Vannote, Robin L. |year=1982 |title=Population Synchrony in Mayflies: A Predator Satiation Hypothesis |journal=Evolution |volume=36 |issue=4 |pages=810–822 |doi=10.2307/2407894 |jstor=2407894|pmid=28568232 }}</ref>
== Biology == In Florida, the adults emerge at the end of April or in early May,<ref name="Edmunds" /> and in South Carolina, in the first half of June.{{fact|date=November 2024}} When ready to transform, the nymphs swim to the surface, split their skin, transform into the subimago winged form, and fly off, all in the course of ten to twenty seconds. The exuviae (nymphal skin) float away downstream.<ref name="Sweeney" /> Their emergence is synchronised and the males emerge first, about one and a half hours before sunrise. Male subimagos moult but the females, which emerge soon after the males, remain in the subimago form.<ref>{{cite journal | author1-link=William L. Peters | first1=William L. | last1=Peters | title=Adult life and emergence of ''Dolania americana'' in Northwestern Florida (Ephemeroptera: Behningiidae) | last2=Peters | first2=Janice G. | journal=Hydrobiology | year=1977 | volume=62 | issue=3 | pages=409–438 | doi=10.1002/iroh.1977.3510620306 | quote=The adult habits and emergence of Dolania americana (Ephemeroptera: Behningiidae) were studied at the Blackwater River in Northwestern Florida. The adult life is crepuscular, beginning about 1½ hrs before sunrise with emergence of male subimagos. Males molt to imagos, female subimagos emerge, males and females mate, and females begin to oviposit in a fairly precise time sequence over the following hour. Only a few adults survive past sunrise. Females never molt to imagos and are polymorphic. Emergence is seasonal and begins between the end of April and the middle of May, depending on climatic conditions. Emergence is photoperiodically entrained.}}</ref>
Having moulted into the adult form within about five minutes of emergence, the males patrol a stretch of river about {{convert|15|to|20|m}} long, seeking out females with which to mate. They continue to do this until they drown, having fallen into the water from exhaustion. Upon emergence, the females mate, deposit their eggs into the water and die within the course of about five minutes.<ref name="Sweeney" /> All the mayflies die within about thirty minutes of emergence.<ref name="Sweeney" />
The eggs are about {{convert|1|mm|2|abbr=on}} in diameter, among the largest of eggs laid by mayflies. The nymphs that hatch out of these burrow into the sediment on the bed of the river using their forelegs and head. Their usual habitat is fairly clean sand in an area with rapidly moving water. They feed on the larvae of chironomids and ceratopogonids. By autumn, they are about one third grown and complete their development within a year.<ref name="Edmunds" />
== References == {{Reflist}}
== External links ==
* [https://georgiabiodiversity.org/profile/profile?group=None&es_id=21325 Dolania americana Edmunds and Traver, 1959] at Georgia biodiversity portal
{{Taxonbar|from1=Q13573762|from2=Q10475391}}
Category:Mayflies Category:Fauna of the Southeastern United States Category:Monotypic insect genera Category:Mayfly genera Category:Insects described in 1959