Asymmetric habitat isolation and sexual isolation predicted by the cost of migration and hybridization generate novel signatures of reinforcing selection

Reinforcement is an evolutionary process whereby increased prezygotic reproductive isolation evolves in response to the cost of hybridization. Despite theory predicting that multiple prezygotic barriers can evolve via reinforcement, most empirical studies examine a single barrier. We test novel predictions for the reinforcement of both habitat isolation and sexual isolation between ecologically divergent lineages under asymmetric migration: the lineage that emigrates more should evolve stronger habitat isolation due to the lower fitness of immigrants in the alternative habitat, while the lineage that receives more immigrants should exhibit stronger sexual isolation due to the lower fitness of hybrids. We found both signatures of reinforcement in two sympatric sister species of gall wasps that are host specific to the southern live oaks, Quercus virginiana and Q. geminata, respectively. Specifically, we observed stronger habitat isolation in the species with higher emigration rates, Belonocnema treatae, and stronger sexual isolation in the species facing more immigrants, B. fossoria. In contrast, comparisons of both species to a third, allopatric, species showed that B. kinseyi exhibited both lower habitat isolation and sexual isolation than the sympatric species, consistent with the classic predictions of reinforcement. Our study provides a rare examination of the interplay of ecology and geography in the evolution of multiple reproductive barriers to gene flow. Given that asymmetric migration between ecologically divergent lineages increasingly appears to be the rule rather than the exception, concomitant asymmetries in the strength of habitat and sexual isolation could be more widespread than currently understood.

New species of Nearctic oak gall wasps (Hymenoptera: Cynipidae, Cynipini)

Twenty nine new species of cynipid oak gall wasps from the Nearctic region (America north of Mexico) are described: Andricus archboldi Melika & Abrahamson, sp. nov., A. catalinensis Melika, Nicholls & Stone, sp. nov., A. chapmanii Melika & Abrahamson, sp. nov., A. chiricahuensis Melika, Nicholls & Stone, sp. nov., A. coconinoensis Melika, Nicholls & Stone, sp. nov., A. columbiensis Melika, Nicholls & Stone, sp. nov., A. cooki Melika, Nicholls & Stone, sp. nov., A. fitzpatricki Melika & Abrahamson, sp. nov., A. highlandensis Melika, Nicholls & Stone, sp. nov., A. mellificus Nicholls, Stone & Melika, sp. nov., A. menkei Melika & Abrahamson, sp. nov., A. mogollonensis Melika, Nicholls & Stone, sp. nov., A. nichollsi Melika & Stone, sp. nov., A. schickae Nicholls, Melika & Stone, sp. nov., A. torreyaensis Melika & Abrahamson, sp. nov., A. williami Melika, Nicholls & Stone, sp. nov., Antron lovellae Melika, Nicholls & Stone, sp. nov., A.tomkursari Melika, Nicholls & Stone, sp. nov., Dryocosmus archboldi Melika & Abrahamson, sp. nov., Loxaulus virginianae Melika & Buss, sp. nov., Neuroterus alexandrae Nicholls & Melika, sp. nov., N. aliceae Melika, Nicholls & Stone, sp. nov., N. bussae Melika & Nicholls, sp. nov., N. oblongifoliae Nicholls, Stone & Melika, sp. nov., N. quaili Melika, Nicholls & Stone, sp. nov., N. rosieae Melika, Nicholls & Stone, sp. nov., N. stonei Melika & Nicholls, sp. nov., Zapatella abrahamsoni Melika, sp. nov., Z. brooksvillei Melika & Abrahamson, sp. nov.. Alternate asexual and sexual generations are described for four species, Andricus archboldi Melika & Abrahamson, sp. nov., A. fitzpatricki Melika & Abrahamson, sp. nov., A. schickae Nicholls, Melika & Stone, sp. nov., Neuroterus aliceae Melika, Nicholls & Stone, sp. nov.. Descriptions, diagnoses, plus information on biology and host associations are given for all new species. All taxa are supported by morphological data; matching of generations is established using DNA sequence data. We also demonstrate that Neuroterus niger var. alimas Kinsey should be considered as a nomen dubium.

A new genus of Neotropical oak gall wasp, Prokius Nieves-Aldrey, Medianero & Nicholls, gen. nov. (Hymenoptera: Cynipidae: Cynipini), with description of two new species from Panama

A new genus, Prokius Nieves Aldrey, Medianero & Nicholls, gen. nov., and two new species of oak gall wasps (Hymenoptera: Cynipidae: Cynipini), Prokius cambrai Medianero & Nieves-Aldrey sp. nov. and Prokius lisethiae Medianero & Nieves-Aldrey sp. nov., are described from adults reared from galls on Quercus bumelioides Liebm (Fagaceae, sect. Quercus, white oaks) collected in Panama. The new genus is phylogenetically and morphologically close to Dros Kinsey and forms part of a large clade that includes species from several other genera that appear to require revision, including Andricus Hartig and Phylloteras Ashmead. Molecular and morphological data, diagnostic characters, gall descriptions, distribution and biological data of the new genus and the new species are given. This new genus represents the fourth recently described genus of Cynipidae endemic to the Neotropical region.

Catalogue of Rose Gall, Herb Gall, and Inquiline Gall Wasps (Hymenoptera: Cynipidae) of the United States, Canada and Mexico

Cynipidae (Hymenoptera: Cynipoidea) is a diverse group of wasps, many of which are capable of inducing plants to make galls, novel structures that protect and nourish the wasps' larvae. Other cynipids, especially those species in Ceroptresini and Synergini, are understood to be usurpers of galls made by other cynipids. The North American cynipid fauna has not been fully catalogued since 1979, but there is renewed interest in revising the taxonomy and in doing research that sheds light on the mechanisms of gall induction, the evolution of this life history, and their ecological interactions more broadly. Significant taxonomic changes have impacted the group since 1979, thereby warranting a new catalogue. The current state of knowledge of species classified in Aulacideini, Ceroptresini, Diastrophini, Diplolepidini, Phanacidini and Synergini in the United States, Canada, and Mexico is summarised in catalogue format. We report 323 names, including 170 valid species of rose gall wasps, herb gall wasps, and inquiline gall wasps, classified in 12 genera, from the United States, Canada, and Mexico. Current taxonomic status, distribution, host associations, and vernacular names are listed for each species. The catalogue also includes the original description of galls for many species of gall-inducer, as well as atomised characterisations of different gall traits as key-value pairs. For most galling species without existing vernacular names, new vernacular names are proposed.

Three new species of herb gall wasps (Hymenoptera: Cynipidae) from Turkey

Three new species of herb gall wasps (Cynipidae: Aulacideini and Phanacidini) are described from Turkey. Aulacidea turguti sp. nov. induces galls on Hieracium patentissimum Freyn & Sint. ex Freyn, 1895 (Asteraceae) and was collected in Gümüşhane province, Phanacis ciceki sp. nov. and Phanacis urhani sp. nov. were collected in Gümüşhane and Ordu Provinces, the former inducing galls on Picris sp. and the latter on Cirsium vulgare (Savi) Ten., 1835–36 (Asteraceae). SEM images, gall photos, distribution, biology, and diagnostic morphological characteristics of the three new species are provided.

Three new Nearctic genera of oak cynipid gall wasps (Hymenoptera: Cynipidae: Cynipini): Burnettweldia Pujade-Villar, Melika & Nicholls, Nichollsiella Melika, Pujade-Villar & Stone, Disholandricus Melika, Pujade-Villar & Nicholls; and re-establishment of the genus Paracraspis Weld

We describe three new genera of cynipid oak gall wasps from the Nearctic: Burnettweldia Pujade-Villar, Melika & Nicholls, gen. nov., Nichollsiella Melika, Pujade-Villar & Stone, gen. nov., and Disholandricus Melika, Pujade-Villar & Nicholls, gen. nov. (Hymenoptera: Cynipidae: Cynipini). Burnettweldia includes five species, B. californicordazi Cuesta-Porta, Melika & Pujade-Villar, sp. nov., B. conalis (Weld), comb. nov., B. corallina (Bassett), comb. nov., B. plumbella (Kinsey), comb. nov., B. washingtonensis (Gillette), comb. nov.. Nichollsiella includes three species, N. arizonica (Cockerell), comb. nov., N. sulcata (Ashmead), comb. nov., and N. puigi Melika, Cuesta-Porta & Pujade-Villar, sp. nov.. Disholandricus includes four species, D. chrysolepidis (Ashmead), comb. nov., D. lasius (Ashmead), comb. nov., D. reniformis (McCracken & Egbert), comb. nov., D. truckeensis (Ashmead), comb. nov. The genus Paracraspis Weld, comb. rev. is re-established with three species, P. guadaloupensis (Fullaway), P. insolens (Weld), and P. patelloides (Trotter). Descriptions, re-descriptions, diagnoses, keys to genera and species are given, including data on DNA sequences, biology, phenology and distribution.

A Case of Intragenic Recombination Dramatically Impacting the Phage WO Genetic Diversity in Gall Wasps

The phage WO was characterized in Wolbachia, a strictly intracellular bacterium causing several reproductive alterations in its arthropod hosts. This study aimed to screen the presence of Wolbachia and phage WO in 15 gall wasp species from six provinces of southern China to investigate their diversity and prevalence patterns. A high incidence of Wolbachia infection was determined in the gall wasp species, with an infection rate of 86.7% (13/15). Moreover, seven species had double or multiple infections. All Wolbachia-infected gall wasp species were found to harbor phage WO. The gall wasp species infected with a single Wolbachia strain were found to harbor a single phage WO type. On the contrary, almost all species with double or multiple Wolbachia infections harbored a high level of phage WO diversity (ranging from three to 27 types). Six horizontal transfer events of phage WO in Wolbachia were found to be associated with gall wasps, which shared identical orf7 sequences among their respective accomplices. The transfer potentially took place through gall inducers and associated inquilines infected with or without Wolbachia. Furthermore, 10 putative recombination events were identified from Andricus hakonensis and Andricus sp2, which harbored multiple phage WO types, suggesting that intragenic recombination was the important evolutionary force, which effectively promoted the high level of phage WO diversity associated with gall wasps.

Chromosomes of three gall wasps of the tribe Aylacini (Hymenoptera, Cynipidae)

Chromosomes of two species of the tribe Aylacini (Cynipidae), Isocolus jaceae (Schenck, 1863) and I. scabiosae (Giraud, 1859) (both have 2n = 18) were studied for the first time. In addition, 2n = 20 is confirmed in a member of the same tribe, Aulacidea hieracii (Bouché, 1834). All chromosomes of these gall wasps are biarmed; however, they gradually decrease in size in the case of A. hieracii, whereas a pair of large metacentrics is characteristic of karyotypes of both Isocolus Förster, 1869 species. Chromosomes of the two latter gall wasps are either metacentric or submetacentric, but elements with lower centromeric indices prevail in the karyotype of A. hieracii. Chromomycin A3 (CMA3)/DAPI staining revealed single CMA3-positive bands on a particular pair of chromosomes of all species, and these bands apparently refer to the nucleolus organizing regions (NORs). However, localization of CMA3-positive bands differs substantially between the studied members of Isocolus and Aulacidea Ashmead, 1897. Together with normal haploid and diploid mitotic divisions, several metaphase plates with 2n = 17 containing a peculiar dicentric chromosome were found in a single male specimen of I. scabiosae; this appears to be the first report of an obvious dicentric in the order Hymenoptera in general. Certain aspects of the chromosome diversity and karyotype evolution within the family Cynipidae and the tribe Aylacini in particular are briefly discussed.

Catalog of Rose Gall, Herb Gall, and Inquiline Gall Wasps (Hymenoptera: Cynipidae) of the United States, Canada, and Mexico

Cynipidae (Hymenoptera: Cynipoidea) is a diverse group of wasps, many of which are capable of inducing plants to make novel structures, galls, that protect and nourish the wasps' larvae. Other cynipids, especially those species in Ceroptresini and Synergini, are understood to be usurpers of galls made by other cynipids. The North American cynipid fauna has not been fully cataloged since 1979, but there is renewed interest in revising the taxonomy and in doing research that sheds light on the mechanisms of gall induction, the evolution of this life history, and their ecological interactions more broadly. Significant taxonomic changes have impacted the group since 1979, thereby warranting a new catalog. The current state of knowledge of species classified in Aulacideini, Ceroptresini, Diastrophini, Diplolepidini, Phanacidini, and Synergini in the United States, Canada, and Mexico is summarized in catalog format. We report 323 names, including 170 valid species of rose gall wasps, herb gall wasps, and inquiline gall wasps, classified in 12 genera, from the United States, Canada, and Mexico. Current taxonomic status, distribution, host associations, and vernacular names are listed for each species. The catalog also includes the original description of galls for many species of gall-inducer, as well as atomized characterizations of different gall traits as key-value pairs. For most galling species without existing vernacular names, new vernacular names are proposed.