Rohlf, FJ, and M Corti. “Use of Two-Block Partial Least-Squares to Study Covariation in Shape.” SYSTEMATIC BIOLOGY 49, no. 4 (December 2000): 740–53.


On 7/7/17 6:18 AM, Alexander Blanke wrote:
Dear all,

the world of morphometrics is relatively new to me, so forgive me if
this question is an old hat:

I would like to know whether two structures, which are not connected to
each other, show concerted shape variation (potentially in response to
functional demands which act on both structures in the same way).

The example here are dragonfly fore- and hindwings. To test whether
these two structures show correlated shape variation I created a set of
landmarks like in the attached file. However, I am a bit unsure how to
proceed. Obviously it is not advisable to use tests which require one
set of landmarks which have been Procrustes superimposed since we are
talking here about two independent structures which are not attached to
each other (Fore- and hindwings can vary in their position to each other
which has nothing to do with a real “shape signal” but is simply due to
the placement of the wings when capturing the images).

I think I need to perform two independent Procrustes superimpositions
and go from there. If I understood correctly, it is then not possible to
use functions such as the integration.test in geomorph since all
partitions used in this test need to stem from one set of Procrustes
aligned landmarks. Maybe I am too focused on tests concerned with
integration and modularity…

My search in the literature was so far not successful since most of the
tests of modularity and integration concern connected structures. My
expectation for the wings is that fore- and hindwings show correlated
shape variation due to the functional demands of flight. Certain parts
of the forewing will “influence” the hindwing shape due to alterations
of the flight performance. I have gathered a few functional parameters
to do further testing of this hypothesis (the total dataset contains 192
species each with ~122 landmarks) but first I want to get this shape
analysis right.

If I missed literature on that topic I would be grateful for any hint to
further reading.

Thanks in advance for your thoughts,


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