Transcript D. waddingtoni

Hawaiian
Drosophila
“Since I became aware, many years ago, of the
astonishing development of Drosophila in Hawai’i, I
have tried to interest geneticists and evolutionists in
the fauna, but I fear that it has been considered, at
least by some workers, that my descriptions of the
size and diversity of the fauna are exaggerated. I do
not exaggerate.
There may be as many as 300 species concentrated
in an area smaller than the little state of
Massachusetts or less than one-fifth the size of
Ireland. Where else has such a drosophilid fauna
developed?”
EC Zimmerman
Hawaiian
Drosophila
- 1,000 endemics
- single colonist
- ancient: 25 mya
- complex history
- diverse behavior
& morphology
- ecological
specialization
80% of picture wing species utilize a single type of host.
The spoon tarsus subgroup
A clade of 13
species placed in
the modified tarsus
species group.
Eight taxa are sympatric on the Big
Island. These are closely related, yet
morphologically distinguishable.
D. waddingtoni, is also found
on Maui Nui.
Founder effect speciation
Large, polymorphic, outcrossed ancestral
population
One or a few colonists found a new population
Selection is temporarily relaxed; drift acts to
disrupt coadapted gene complexes
Population “flushes” and rapidly increases in
size; genetic variation carries through;
selection is reestablished; species may occupy
a new location in the adaptive landscape
Wings
Sc
D. grimshawi
Legs
D. quasiexpansa
D. waddingtoni
D. proceriseta
Head
compound eye
antennae
mouthparts
sclerites
chaetotaxy
D. adunca
Mouthparts
palps
number and position of setae
labellum
specialized modifications in Hawaiian taxa
D. adventitia
labium
labrum
D. multiciliata