Comparative morphology of terminal-instar larvae of Cynipoidea: phylogenetic implications

• Published in: Zoologica scripta 2005-01, Vol.34 (1), p.15-36
• Main Authors: Nieves-Aldrey, José Luis, Vårdal, Hege, Ronquist, Fredrik
• Format: Article
• Language: English
• Subjects: Cynipidae; Cynipoidea; Hymenoptera
• ISSN: 0300-3256; 1463-6409
• DOI: 10.1111/j.1463-6409.2005.00175.x

We describe the external morphology of the terminal‐instar larvae of 30 species of Cynipoidea (Hymenoptera), with special reference to the head capsule and mouthparts. Twenty‐five of the species belong to the Cynipidae and are gall inducers or phytophagous inquilines (guests) in galls, while five represent different insect‐parasitic lineages of the Cynipoidea. Although we find only limited variation in body shape, the head sclerites and mandibles offer many characters of potential phylogenetic value. For instance, the mandibles of the parasitoids have one large pointed tooth, with several smaller dents along the inner margin in core figitids, whereas the phytophagous gall inducers and inquilines have mandibles with two or three blunt teeth of subequal size. The mandibles of inquiline larvae are unique in being covered by vertical striations and in having a dominating, broad second tooth. We summarize the qualitative variation among the studied terminal‐instar larvae in terms of 33 morphological characters and one life‐history trait and examine the phylogenetic implications of these data by running parsimony analyses under uniform character weights and under implied weights (Goloboff weights). The analysis under uniform weights is poorly resolved but the relationships suggested by the implied‐weights analysis are largely congruent with previous analyses of adult morphology and molecular data. The larval data support inclusion of the genus Liposthenes in the Neaylax–Isocolus clade, in agreement with the molecular data but in weak conflict with adult morphology. However, the larval data agree with adult morphology and conflict with the molecular data in supporting monophyly of the inquilines.