Systematics and biology of the aberrant intertidal parasitoid wasp Echthrodesis lamorali Masner (Hymenoptera : Platygastridae s.l.): a parasitoid of spider eggs

Abstract

Abstract. The platygastroid wasp Echthrodesis lamorali has been of considerable interest since its description in 1968, primarily because of its highly modified, densely pilose, wingless body, its distribution and unusual biology. The species is endemic to the Cape Peninsula, South Africa, where it is an endoparasitoid of eggs of the marine spiders Desis formidabilis (Desidae) and Amaurobioides africanus (Anyphaenidae) in the intertidal region. Although a highly aberrant monospecific genus, the phylogenetic relationships of Echthrodesis are confused, in part due to convergence in body form across numerous unrelated platygastroid genera. We used sequence data from the nuclear 28S rRNA and 18S rDNA genes, and the mitochondrial cytochrome oxidase 1 (CO1) gene, to determine the phylogenetic affinities of E. lamorali. We present a revised taxonomic description for the genus and species, as well as new morphological information on the structure of its mouthparts and ovipositor system. Phylogenetic analyses of molecular data place E. lamorali within one of two independent clades of platygastroid wasps that use spider eggs as hosts. Echthrodesis is sister to a group of three genera: Neobaeus (New Zealand; host unconfirmed); Mirobaeoides (Australia; spider eggs); and Embidobia (near cosmopolitan; embiid eggs). Details on the biology, behaviour and morphological adaptations of E. lamorali are provided.

Assessing the morphological and physiological adaptations of the parasitoid wasp Echthrodesis lamorali for survival in an intertidal environment

“…Echthrodesis lamorali Masner, 1968 (Hymenoptera: Platygastridae, Scelioninae) is an endoparasitoid of the egg stage of the intertidal South African spider Desis formidabilis O.P. Cambridge 1890 (Araneae: Desidae) (Lamoral, ; Masner, ; Branch & Branch, ; van Noort, ; van Noort et al ., ). This wasp displays high endemism, living and surviving only within the intertidal region along a small stretch of the Cape Peninsula (Western Cape, South Africa) (Owen et al ., ), despite a much wider host spider distribution from East London (Eastern Cape, South Africa), around the Peninsula to Namibia (Day, ; Dippenaar‐Schoeman & Jocqué, ).…”

“…This wasp displays high endemism, living and surviving only within the intertidal region along a small stretch of the Cape Peninsula (Western Cape, South Africa) (Owen et al ., ), despite a much wider host spider distribution from East London (Eastern Cape, South Africa), around the Peninsula to Namibia (Day, ; Dippenaar‐Schoeman & Jocqué, ). The habitat of this parasitoid sets the species apart as one of only three other such maritime wasps known worldwide (van Noort et al ., ). Females gain access to the multi‐compartmentalized host spider egg sacs by chewing through their silken walls with strong mandibles, after which they oviposit in all eggs present (van Noort, ; van Noort et al ., ).…”

“…The habitat of this parasitoid sets the species apart as one of only three other such maritime wasps known worldwide (van Noort et al ., ). Females gain access to the multi‐compartmentalized host spider egg sacs by chewing through their silken walls with strong mandibles, after which they oviposit in all eggs present (van Noort, ; van Noort et al ., ). Males eclose first and fight each other over access to their female kin, which emerge next (van Noort et al ., ).…”

“…Females gain access to the multi‐compartmentalized host spider egg sacs by chewing through their silken walls with strong mandibles, after which they oviposit in all eggs present (van Noort, ; van Noort et al ., ). Males eclose first and fight each other over access to their female kin, which emerge next (van Noort et al ., ). The mode of dispersal to other nests is unknown, although it is hypothesized to occur post‐copulation through active searching at low tide by walking between rock pools when the host nests are exposed (van Noort et al ., ).…”

South African National Survey of Arachnida (SANSA): review of current knowledge, constraints and future needs for documenting spider diversity (Arachnida: Araneae)

“…This wasp was first recorded from D. formidabilis eggs by Masner (1968) and Lamoral (1968). Recent biological studies suggest that E. lamorali is restricted in its distribution to the Cape Peninsula, despite the more widespread distribution of its hosts (Van Noort, 2009Owen et al, 2014;Van Noort et al, 2014). Haddad & Dippenaar-Schoeman (2001) reported a Psyllaephagus sp.…”