Evolution in the dark: A study of cave crickets in Southern Appalachia
Loading...
Authors
Harrison, Mary
Issue Date
2007-05-02
Type
Thesis
Language
en_US
Keywords
cave crickets , Tribe Hadenoecini , trogloxenes
Alternative Title
Abstract
In 1978 Hubbell and Norton described nine species of crickets in the Tribe
Hadenoecini found in caves or forest litter in the Southern Appalachians. According to
the model proposed by these authors new species formed during glaciation. Hubbell and
Norton (1978) suggested that the crickets are thermophile relicts that dispersed in the area
before and after glaciation but, during glaciation, formed new species in allopatric refugia
of caves or forests south of their normal ranges. Our mitochondrial DNA sequence
data—the first obtained for members of this group--tested several hypotheses: 1) The
Tribe Hadenoecini is a monophyletic clade when compared with outgroups from their
sister Tribe Dolocopodini, 2) The two genera Euhadenoecus and Hadenoecus are both
monophyletic, 3) The forest Euhadenoecus and the trogloxenic Euhadenoecus are each
monophyletic, 4) The two trogloxenes from Kentucky form a single clade, and the three
most cave-adapted trogloxenes in Tennessee form a single clade. Our preliminary results
support all four of these hypotheses. Our data, however, suggest that the divergence
between the two genera and between the two clades of Hadenoecus occurred well before
the Pleistocene and that only speciation within the two Hadenoecus clades occurred in the
mid to late Pleistocene as suggested by Hubbell and Norton (1978).