[Taxacom] Panbiogeography

[JF Mate]

Hi Michael,

sorry for the delay. Currently with friends and family so I am not
keeping up. In regards to your question,  I work on Aphodiinae (all
aspects)  and with Hydrophiloidea for faunistics.

Regarding Rhagoletis, the papers from Feder et al suggest that the
genes involved in diapause originated, probably, in allopatry and then
spread into the more northern  R. pomonella populations. This does not
exclude sympatric evolution. Instead, basic genetic "adaptive packs"
originated in allopatry and spread into the US populations
(introgression scenario) before human introduction of apples. These
"packs" where selected in toto thanks to the polymorphic inversions,
and their spread facilitated, it is assumed, due to the adaptive
advantage to hawthorn feeding flies along the latitudinal temperature
clines. Afterwards, these inversions would have preadapted R.
pomonella for host switching and the sympatric formation of host
races. So the papers provides a molecular mechanism to sympatry in the
form of "preadaptations". As to the overlap, the SN and N populations
are broadly sympatric and haw feeding and apple feeding flies exist
side by side. It is quite clear in the paper.

Now, my issue with the statement "everything is everywhere (and the
environment selects)" is that it is a bit of a strawman, like blaming
Darwin for dispersalism. Things have changed quite a bit since the
Victorians. We even accept certain forms of quasi-lamarckian
evolution!

Best

Jason