Morphology and function of the ovipositor mechanism in Ceraphronoidea (Hymenoptera, Apocrita)

Abstract

The ovipositor of apocritan Hymenoptera is an invaluable source of phylogenetically relevant characters, and our understanding of its functional morphology stands to enlighten us about parasitoid life history strategies. Although Ceraphronoidea is one of the most commonly collected Hymenoptera taxa with considerable economic importance, our knowledge about their natural history and phylogenetic relationships, both to other apocritan lineages and within the superfamily itself, is limited. As a first step towards revealing ceraphronoid natural diversity we describe the skeletomuscular system of the ceraphronoid ovipositor for the first time. Dissections and Confocal Laser Scanning Microscopy 3D media files were used to visualize the ovipositor complex and to develop character concepts. Morphological structures were described in natural language and then translated into a character-character state format, whose terminology was linked to phenotype-relevant ontologies. Four unique anatomical phenotypes were revealed: 1. The first valvifer (gonangulum) of the genus Trassedia is composed of two articulating sclerites, a condition present only in a few basal insect taxa. The bipartition of the first valvifer in Trassedia is most likely secondary and might allow more rapid oviposition. 2. Ceraphronoids, unlike other Hymenoptera, lack the retractor muscle of the terebra; instead the egg laying device is retracted by the seventh sternite. 3. Also unlike other Hymenoptera, the cordate apodeme and the anterior flange of the second valvifer are fused and compose one ridge that serves as the site of attachment for the dorsal and ventral T9-second valvifer muscles. Overall, the ceraphronoid ovipositor system is highly variable and can be described by discrete, distinguishable character states. However, these differences, despite their discrete nature, do not reflect the present classification of the superfamily and might represent parallelisms driven by host biology.

Morphology and life history of an ant parasitoid, Psilocharis afra (Hymenoptera: Eucharitidae)

“…We follow Vilhelmsen (2000b) for naming of muscles. In Psilocharis and most other Chalcidoidea, Mt 8 and Mt 9 are fused, but we follow other studies that suggest that muscles connect to Mt 8 (T9 of Ernst et al 2013). M5 originates on the dorsal surface of Mt 8 and inserts on the anterior section of the dorsal flanges of the second valvifer (HAO_0001569).…”

“…The general structure of the ovipositor for Eucharitidae is as described and illustrated by Heraty & Quicke (2003), Heraty & Darling (2007), Heraty (2003, and , but here we try to harmonize our terminology for structures and muscles with Vilhelmsen (2000b) and Ernst et al (2013). The articulating bulb in Psilocharis is an elongate structure composed proximally by the pars articularis (Fig 27: paa; 2 nd valvifer in part) and the processus musculares (Fig 27: pmu; 2 nd valvula in part).…”

Revision of the Polynema dikobraz species-group with description of a remarkable new species from South Africa (Hymenoptera, Chalcidoidea, Mymaridae)

“…Based on the presence of annuli at the tip of the ovipositor, which are an adaption to drill through hard surfaces (Ernst et al 2013, Quicke et al 1999, Le Ralec et al 1996), we hypothesize that the host eggs themselves, or the substrate within which they are concealed is hard.…”

Pteroceraphron Dessart new to the USA (Hymenoptera: Ceraphronoidea)

“…The family Ceraphronidae is one of the most commonly collected microhymenopterans (Martínez de Murgía et al 2001, Schmitt 2004). External somatic morphology is relatively monotonous and the morphological diversity of the male genitalia is extraordinary (Mikó et al 2013, Ernst et al 2013). Pteroceraphron stands apart from other ceraphronid genera by having lanceolate fore wings ornamented with elongate marginal setae (Fig.…”