Data from: Anatomy of a neotropical insect radiation

Background: Much evolutionary theory predicts that diversity arises via
both adaptive radiation (diversification driven by selection against
niche-overlap within communities) and divergence of geographically
isolated populations. We focus on tropical fruit flies (Blepharoneura,
Tephritidae) that reveal unexpected patterns of niche-overlap within local
communities. Throughout the Neotropics, multiple sympatric
non-interbreeding populations often share the same highly specialized
patterns of host use (e.g., flies are specialists on flowers of a single
gender of a single species of host plants). Lineage through time (LTT)
plots can help distinguish patterns of diversification consistent with
ecologically limited adaptive radiation from those predicted by
ecologically neutral theories. Here, we use a time-calibrated phylogeny of
Blepharoneura to test the hypothesis that patterns of Blepharoneura
diversification are consistent with an “ecologically neutral” model of
diversification that predicts that diversification is primarily a function
of time and space. Results: The Blepharoneura phylogeny showed more
cladogenic divergence associated with geography than with shifts in
host-use. Shifts in host-use were associated with ~20% of recent splits
(<3 Ma), but >60% of older splits (>3 Ma). In the
overall tree, gamma statistic and maximum likelihood model fitting showed
no evidence of diversification rate changes though there was a weak
signature of slowing diversification rate in one of the component clades.
Conclusions: Overall patterns of Blepharoneura diversity are inconsistent
with a traditional explanation of adaptive radiation involving decreases
in diversification rates associated with niche-overlap. Sister lineages
usually use the same host-species and host-parts, and multiple
non-interbreeding sympatric populations regularly co-occur on the same
hosts. We suggest that most lineage origins (phylogenetic splits) occur in
allopatry, usually without shifts in host-use, and that subsequent
dispersal results in assembly of communities composed of multiple
sympatric non-interbreeding populations of flies that share the same
hosts.