Morphometrics underwent a revolution more than one decade ago. In the modern morphometrics, the
estimate of size is now contained in a single variable reflecting variation in many directions, as many as
there are landmarks under study, and shape is defined as their relative positions after correcting for size,
position and orientation. With these informative data, and the corresponding software freely available to
conduct complex analyses, significant biological and epidemiological features can be quantified more
accurately.
Wediscuss the evolutionary significance of the environmental impact on metric variability, mentioning
the importance of concepts like genetic assimilation, genetic accommodation, and epigenetics.Weprovide
examples of measuring the effect of selection on metric variation by comparing (unpublished) Qst values
with corresponding (published) Fst.
The primary needs ofmedical entomologists are to distinguish species, especially cryptic species, and
to detect them where they are not expected. We explain how geometric morphometrics could apply to
these questions, and where there are deficiencies preventing the approach from being utilized at its
maximum potential.
Medical entomologists in connection with control programs aim to identify isolated populations
where the risk of reinfestation after treatment would be low (‘‘biogeographical islands’’). Identifying
them can be obtained from estimating the number of migrants per generation. Direct assessment of
movement remains the most valid approach, but it scores active movement only. Genetic methods
estimating gene flow levels among interbreeding populations are commonly used, but gene flowdoes not
necessarily mean the current flow of migrants. Methods using the morphometric variation are neither
suited to evaluate gene flow, nor are they adapted to estimate the flow of migrants. They may provide,
however, the information needed to create a preliminary map pointing to relevant areas where one could
invest in using molecular machinery.
In case of reinfesting specimens after treatment, the question relates to the likely source of reinfesting
specimens: are they a residual sample not affected by the control measures, or are they individuals
migrating from surrounding, untreated foci? We explain why the morphometric approach may be
adapted to answer such question.
Thus, we describe the differences between estimating the flow of migrants and identifying the source
of reinfestation after treatment: althoughmorphometrics is not suited to deal with the former, it may be
an appropriate tool to address the latter.
Morphometrics underwent a revolution more than one decade ago. In the modern morphometrics, theestimate of size is now contained in a single variable reflecting variation in many directions, as many asthere are landmarks under study, and shape is defined as their relative positions after correcting for size,position and orientation. With these informative data, and the corresponding software freely available toconduct complex analyses, significant biological and epidemiological features can be quantified moreaccurately.Wediscuss the evolutionary significance of the environmental impact on metric variability, mentioningthe importance of concepts like genetic assimilation, genetic accommodation, and epigenetics.Weprovideexamples of measuring the effect of selection on metric variation by comparing (unpublished) Qst valueswith corresponding (published) Fst.The primary needs ofmedical entomologists are to distinguish species, especially cryptic species, andto detect them where they are not expected. We explain how geometric morphometrics could apply tothese questions, and where there are deficiencies preventing the approach from being utilized at itsmaximum potential.Medical entomologists in connection with control programs aim to identify isolated populationswhere the risk of reinfestation after treatment would be low (‘‘biogeographical islands’’). Identifyingthem can be obtained from estimating the number of migrants per generation. Direct assessment ofmovement remains the most valid approach, but it scores active movement only. Genetic methodsestimating gene flow levels among interbreeding populations are commonly used, but gene flowdoes notnecessarily mean the current flow of migrants. Methods using the morphometric variation are neithersuited to evaluate gene flow, nor are they adapted to estimate the flow of migrants. They may provide,however, the information needed to create a preliminary map pointing to relevant areas where one couldinvest in using molecular machinery.In case of reinfesting specimens after treatment, the question relates to the likely source of reinfestingspecimens: are they a residual sample not affected by the control measures, or are they individualsmigrating from surrounding, untreated foci? We explain why the morphometric approach may beadapted to answer such question.Thus, we describe the differences between estimating the flow of migrants and identifying the sourceof reinfestation after treatment: althoughmorphometrics is not suited to deal with the former, it may bean appropriate tool to address the latter.
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