Multivariate morphometrics of geographic variation of Gerris costae (Heteroptera: Gerridae) in Europe

C P Klingenberg
1992 Revue suisse de zoologie  
The waterstrider species Gerris costae (Herrich-Schaeffer) has a large and disjunct distribution in the southern part of the palearctic region. Multivariate morphometric techniques were used to assess the geographic variation in the European part of its range, where three subspecies are currently recognized: G. c. costae (Herrich-Schaeffer), G. c. fieberi Stichel, and G. c. poissoni Wagner and Zimmermann. Twelve variables were selected from a larger set (56 or 57 variables for males and
more » ... respectively) by stepwise discriminant analysis, and were found to represent the main patterns of morphometric variation in the full character set. Principal component analysis revealed that both 'size' and 'shape' contribute to geographic differentiation. Canonical variate analysis with two different criteria for the definition of a priori groups showed that the subspecies are coherent units separate from each other, and that the segregation into the three subspecies indeed reflects the main pattern of geographic variation in Europe. Comparisons of field samples with offspring reared in the laboratory under standardized conditions demonstrated that geographic differentiation is genetically determined for the most part. The study therefore supports the segregation of Gerris costae into three subsepcies in the area considered. Linear discriminant functions are given to allocate additional material to the subspecies.
doi:10.5962/bhl.part.79819 fatcat:rnj5v3ljqbc3rm7ynercalpxly