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Acknowledgments: C.B. and K. Y. were funded by NSF
EAR grants 0838605 and 0949255; N.S. was funded by NSF
EAR 1247608. We thank J. Trampert and K. Visser for
making their phase velocity maps freely available. Partial
derivatives were calculated using fortran code MINEOS
( www.geodynamics.org/cig/software/mineos), and figures
were made with the Generic Mapping Tools, Gnuplot, and
Xmgrace. We thank P. Davis for fruitful discussions. The
data used were the phase velocity maps published in (12) and
are available at www.geo.uu.nl/~jeannot/My_web_pages/
Downloads.html. The models are available in the
Materials and Methods
Figs. S1 to S27
Model file S1
2 October 2013; accepted 17 February 2014
Published online 27 February 2014;
Lethal Interactions Between Parasites
and Prey Increase Niche Diversity
in a Tropical Community
Marty A. Condon,1 Sonja J. Scheffer,2 Matthew L. Lewis,2 Robert Wharton,3
Dean C. Adams,4,5 Andrew A. Forbes6
Ecological specialization should minimize niche overlap, yet herbivorous neotropical flies (Blepharoneura)
and their lethal parasitic wasps (parasitoids) exhibit both extreme specialization and apparent niche
overlap in host plants. From just two plant species at one site in Peru, we collected 3636 flowers yielding
1478 fly pupae representing 14 Blepharoneura fly species, 18 parasitoid species (14 Bellopius species),
and parasitoid-host associations, all discovered through analysis of molecular data. Multiple sympatric
species specialize on the same sex flowers of the same fly host-plant species—which suggests extreme
niche overlap; however, niche partitioning was exposed by interactions between wasps and flies. Most
Bellopius species emerged as adults from only one fly species, yet evidence from pupae (preadult
emergence samples) show that most Bellopius also attacked additional fly species but never emerged as
adults from those flies.
Plant and insect diversity both peak in the tropics (1) where insect diversity is strong- ly associated with plant diversity (2, 3) and
extreme specialization (4). Ecological specializa-
tion is often considered a driver of diversification,
with increasing specialization reducing niche over-
lap and promoting speciation (5, 6). Diversifica-
tion of herbivorous insects, arguably the most
diverse group of organisms on Earth (7), is often
explained by “arms race” or “escape and radiate”
hypotheses involving specialized interactions ei-
ther between two trophic levels—host plants and
Hydrated frozen-in paleo
fast axes in
Fig. 3. Proposed models for azimuthal anisotropy beneath the Pacific
and detection of the G. (A) The G as the top of an anisotropic entrainment
and segregation of melt within the asthenosphere. Dynamical upwelling produces
melt that is entrained into mantle flow and compacts at the base of the lith-
osphere from a solidus-induced change in permeability (10). The G coincides with
the top of the melting zone. In the scenario where the APM and fossil spreading
directions are parallel, the G would not be detected. (B) The G as a chemical
boundary between a weakly anisotropic dry layer and a hydrated region char-
acterized by the fossil frozen-in alignment of olivine. Olivine aligns with the
present-day APM in the hydrated, warm asthenosphere. In this scenario, G can
be both coincident with and above the thermally defined LAB and is detected by
the SS precursors where the anisotropy contrast between the two layers is large.