EXPLORING COMPONENT STABILITY USING LIFE-STAGE CONCORDANCE IN SABETHINE MOSQUITOS (DIPTERA, CULICIDAE)

Morphological characters from sabethine mosquitoes were coded from lar vae, pupae and adults, and life-stage partitions were evaluated to det ermine the contribution of each to the topology of a combined cladogra m. Initial tests failed to find congruence between characters partitio ned by life stage. However, when components from the combined analysis were tested using reduced taxon sets, a high degree of concordance be tween partitions was observed. A procedure for assessing individual li fe-stage contribution is employed, in which exhaustive searches are us ed to explore all possible arrangements for each of the selected compo nents. Seven of the 10 components examined were able to recover the co mbined topology with a reduced taxon set. Congruent arrangements of ta xa were typically observed for two or more life stages, although parti tioned data were less resolved and frequently included aberrant topolo gies (those not supported by other partitioned or combined reduced tax on tree sets). In addition, none of the partitioned data sets gave rob ust results for all tests, suggesting that studies which emphasize cha racter data from single life stages may support misleading arrangement s of taxa. One component on the combined cladogram was not supported b y any of the life-stage partitions when analysed separately. These res ults are complementary to ''total evidence'' approach, and demonstrate that partitions of data are useful for examining suits of characters which may cause some components of the ''total evidence'' tree to appe ar unstable. (C) 1998 The Willi Hennig Society.