The Chalcidoidea bush of life: evolutionary history of a massive radiation of minute wasps

Abstract

Chalcidoidea are mostly parasitoid wasps that include as many as 500 000 estimated species. Capturing phylogenetic signal from such a massive radiation can be daunting. Chalcidoidea is an excellent example of a hyperdiverse group that has remained recalcitrant to phylogenetic resolution. We combined 1007 exons obtained with Anchored Hybrid Enrichment with 1048 ultra‐conserved elements (UCEs) for 433 taxa including all extant families, >95% of all subfamilies, and 356 genera chosen to represent the vast diversity of the superfamily. Going back and forth between the molecular results and our collective knowledge of morphology and biology, we detected bias in the analyses that was driven by the saturation of nucleotide data. Our final results are based on a concatenated analysis of the least saturated exons and UCE datasets (2054 loci, 284 106 sites). Our analyses support an expected sister relationship with Mymarommatoidea. Seven previously recognized families were not monophyletic, so support for a new classification is discussed. Natural history in some cases would appear to be more informative than morphology, as illustrated by the elucidation of a clade of plant gall associates and a clade of taxa with planidial first‐instar larvae. The phylogeny suggests a transition from smaller soft‐bodied wasps to larger and more heavily sclerotized wasps, with egg parasitism as potentially ancestral for the entire superfamily. Deep divergences in Chalcidoidea coincide with an increase in insect families in the fossil record, and an early shift to phytophagy corresponds with the beginning of the “Angiosperm Terrestrial Revolution”. Our dating analyses suggest a middle Jurassic origin of 174 Ma (167.3–180.5 Ma) and a crown age of 162.2 Ma (153.9–169.8 Ma) for Chalcidoidea. During the Cretaceous, Chalcidoidea may have undergone a rapid radiation in southern Gondwana with subsequent dispersals to the Northern Hemisphere. This scenario is discussed with regard to knowledge about the host taxa of chalcid wasps, their fossil record and Earth's palaeogeographic history.

Exploration for Asian longhorned beetle parasitoids in Korea using an improved sentinel log trap

“…The phylogenetic analysis, not surprisingly because of their higher saturation [ 11 ], recovered serious polyphyly of all the major families of Chalcidoidea, which was divided into numerous clades ( Fig. 4B ).…”

“…However, all families of Chalcidoidea were super-polyphyletic in both the ML and NJ phylogenetic trees. The polyphyly was expected because COI is generally a poor marker for a deep-time phylogenetic relationship, which is a fast-evolving marker with higher saturation [ 11 ]. A BLAST nucleotide search suggested that the parasitoid pupal sequence is closest to A. ceroplastae ; however, the identical base pair percentage was too low (88.4%) to be of the same species (recommended threshold: 2–3%; [ 24 , 40 ]).…”

Redefining Ormyridae (Hymenoptera, Chalcidoidea) with establishment of subfamilies and description of new genera

“…According to the recently revised classification of Chalcidoidea by Burks et al (2022) and Cruaud et al (2024), most chalcidoid gallassociates are placed in the families Cynipencyrtidae, Epichrysomallidae, Melanosomellidae, Ormyridae and Tanaostigmatidae (Burks et al, 2022). Together, these taxa comprise the so called 'Gall Clade' sensu Burks et al (2022) and Cruaud et al (2024).…”

“…According to the recently revised classification of Chalcidoidea by Burks et al (2022) and Cruaud et al (2024), most chalcidoid gallassociates are placed in the families Cynipencyrtidae, Epichrysomallidae, Melanosomellidae, Ormyridae and Tanaostigmatidae (Burks et al, 2022). Together, these taxa comprise the so called 'Gall Clade' sensu Burks et al (2022) and Cruaud et al (2024). Cynipencyrtidae contains two enigmatic species: Cynipencyrtus flavus Ishii, a parasitoid of gall wasps (Cynipidae) (Ito & Hijii, 2000;Tachikawa, 1973Tachikawa, , 1978, and Cynipencyrtus indicus Singh collected from Quercus leucotrichophora forest (Singh, 2008).…”

Orthoptera-specific target enrichment (OR-TE) probes resolve relationships over broad phylogenetic scales

“…Moreover, many polyneopteran insects have larger genome sizes than holometabolous insect orders 16 , contributing to the general lack of genome sequencing projects in these groups. Molecular systematists studying Coleoptera, Diptera, Hymenoptera, and Lepidoptera were early adopters of this technique into their toolkits, resulting in ground-breaking phylogenomic studies with extensive taxon sampling 7,9,[17][18][19][20][21][22][23][24][25] . Now, pre-designed probes are commercially available for these insect orders.…”