Molecular phylogenetic analysis of evolutionary trends in stonefly wing structure and locomotor behavior

Abstract

Insects in the order Plecoptera (stoneflies) use a form of two-dimensional aerodynamic locomotion called surface skimming to move across water surfaces. Because their weight is supported by water, skimmers can achieve effective aerodynamic locomotion even with small wings and weak flight muscles. These mechanical features stimulated the hypothesis that surface skimming may have been an intermediate stage in the evolution of insect flight, which has perhaps been retained in certain modern stoneflies. Here we present a phylogeny of Plecoptera based on nucleotide sequence data from the small subunit rRNA (18S) gene. By mapping locomotor behavior and wing structural data onto the phylogeny, we distinguish between the competing hypotheses that skimming is a retained ancestral trait or, alternatively, a relatively recent loss of flight. Our results show that basal stoneflies are surface skimmers, and that various forms of surface skimming are distributed widely across the plecopteran phylogeny. Stonefly wings show evolutionary trends in the number of cross veins and the thickness of the cuticle of the longitudinal veins that are consistent with elaboration and diversification of flight-related traits. These data support the hypothesis that the first stoneflies were surface skimmers, and that wing structures important for aerial flight have become elaborated and more diverse during the radiation of modern stoneflies.

Insect phylogenomics: results, problems and the impact of matrix composition

“…Eukinolabia [4]). This relationship has first been proposed by Rähle [54] and is corroborated by recent studies based on nuclear rRNA, protein-coding genes [4,7,55,56] and morphological features [45,46,57]. Our results do not support the traditional clade stick insects þ crickets, katydids, grasshoppers and related groups (i.e.…”

A respiratory hemocyanin from an insect

“…Why stoneflies in particular have retained this oxygen transport molecule in their blood remains an interesting question. Although the Plecoptera possess what appears to be a typically developed insect tracheal system, they have a number of ancestral features, and are aquatic as nymphs and are semiaquatic as adults (17)(18)(19). Thus, it is likely that the presence of a Hc in stoneflies reflects an intermediate state in the transformation from a crustacean to an insect respiratory system.…”

“…Stoneflies (Plecoptera) arose near the base of one of the two main branches of winged insects and have retained many ancestral morphological and behavioral traits (17)(18)(19). Thus, we reasoned that stoneflies might be an especially likely group to have retained partial reliance on an ancestral form of gas exchange and use Hcs for oxygen transport.…”

Were the first springtails semi-aquatic? A phylogenetic approach by means of 28S rDNA and optimization alignment

“…That aquatic scenario for the origin of hexapods is rather widespread and has been advocated for some time (e.g. Riek 1971;Kukalová-Peck 1978;Tom 1984;Thomas et al 2000). It is based on the fact that the pterygote groups generally regarded as 'primitive' have aquatic larvae: mayflies (Ephemeroptera), dragonflies and damselflies (Odonata), stoneflies (Plecoptera), alderflies and dobsonflies (Megaloptera) and caddisflies (Trichoptera).…”