Editor's column: Planktic, nektic, benthic

The terms planktic, nektic , and benthic are taken as examples of the construction and malconstruction of biological and geological terms. Both in vernacular terminology and systematic nomenclature the formation of adjectives and compounds follows the same basic rules - keep the three concepts of stem, suffix, and connective vowel clear, and most of the serious malconstructions will be avoided.     

Editor's column: Nemagraptus, Pelekysgnathus, Foramenella

Systematic nomenclature follows the same rules for compounding and derivation as the scientific terminology discussed in a preceding Editor's Column. Lethaia honours appealing and correctly constructed names (and terms), but the codes of biological nomenclature do not in practice permit 'justified emendations' of names which do not meet the linguistic requirements in the same codes - in practice priority in 'spelling' supersedes correctness in 'language'. Construction of systematic names is easy, and the introduction of further incorrect and mnemonically cumbersome forms is easily curbed by requiring a statement on the derivation of each new name, scrutinized by a linguist if necessary.     

The cost of secondary sexual characters and the evolution of cost-reducing traits

Secondary sexual traits are characterized by their exaggerated expression relative to homologous nonsexual characters in other species. All models of sexual selection assume that sex traits are costly to produce and maintain, and individuals with reduced costs of production and maintenance of secondary sexual characters would be at a selective advantage. A number of morphological, physiological and behavioural traits may have evolved as a result of their cost-reducing properties: (1) body size, which does not change throughout life, that allows certain individuals to develop exaggerated sex traits, (2) cost-reducing traits, such as muscle size, that improve with practice and (3) actual cost-reducing traits, such as wing size in birds with song flight, which are produced in advance of or simultaneously with the sex trait. Cost-reducing traits may coevolve with secondary sexual characters and allow more extreme sexual signalling than would otherwise have been possible in their absence or in reduced versions.