John T. Huber

Fluctuations in density of an outbreak species drive diversity cascades in food webs

Patterns in food-web structure have frequently been examined in static food webs, but few studies have attempted to delineate patterns that materialize in food webs under nonequilibrium conditions. Here, using one of natures classical nonequilibrium systems as the food-web database, we test the major assumptions of recent advances in food-web theory. We show that a complex web of interactions between insect herbivores and their natural enemies displays significant architectural flexibility over a large fluctuation in the natural abundance of the major herbivore, the spruce budworm (Choristoneura fumiferana). Importantly, this flexibility operates precisely in the manner predicted by recent foraging-based food-web theories: higher-order mobile generalists respond rapidly in time and space by converging on areas of increasing prey abundance. This “birdfeeder effect” operates such that increasing budworm densities correspond to a cascade of increasing diversity and food-web complexity. Thus, by integrating foraging theory with food-web ecology and analyzing a long-term, natural data set coupled with manipulative field experiments, we are able to show that food-web structure varies in a predictable manner. Furthermore, both recent food-web theory and longstanding foraging theory suggest that this very same food-web flexibility ought to be a potent stabilizing mechanism. Interestingly, we find that this food-web flexibility tends to be greater in heterogeneous than in homogeneous forest plots. Because our results provide a plausible mechanism for boreal forest effects on populations of forest insect pests, they have implications for forest and pest management practices.

DNA barcoding reveals diversity of Hymenoptera and the dominance of parasitoids in a sub-arctic environment.

BackgroundInsect diversity typically declines with increasing latitude, but previous studies have shown conflicting latitude-richness gradients for some hymenopteran parasitoids. However, historical estimates of insect diversity and species richness can be difficult to confirm or compare, because they may be based upon dissimilar methods. As a proxy for species identification, we used DNA barcoding to identify molecular operational taxonomic units (MOTUs) for 7870 Hymenoptera specimens collected near Churchill, Manitoba, from 2004 through 2010.ResultsWe resolved 1630 MOTUs for this collection, of which 75% (1228) were ichneumonoids (Ichneumonidae + Braconidae) and 91% (1484) were parasitoids. We estimate the total number of Hymenoptera MOTUs in this region at 2624-2840.ConclusionsThe diversity of parasitoids in this sub-Arctic environment implies a high diversity of potential host species throughout the same range. We discuss these results in the contexts of resolving interspecific interactions that may include cryptic species, and developing reproducible methods to estimate and compare species richness across sites and between surveys, especially when morphological specialists are not available to identify every specimen.

Two new Australian species of Stethynium (Hymenoptera: Mymaridae), larval parasitoids of Ophelimus maskelli (Ashmead) (Hymenoptera: Eulophidae) on Eucalyptus

Two new species of Mymaridae, Stethynium ophelimi Huber and S. breviovipositor Huber, are described from Ophelimus maskelli, a gall‐inducing pest of Eucalyptus camaldulensis accidentally introduced from Australia into the Mediterranean region and Africa. This is the first record of a species of Mymaridae reared as a larval parasitoid of a holometabolous insect. One or both of the Stethynium species are being considered for introduction into Israel for biological control of this pest. Galls containing late second or third instar larvae are suitable for successful development of Stethynium. Mean survival time in a mixed colony of adults fed with honey and water solution was 1–2 days. Stethynium perlatipenne Girault, syn. nov., is synonymized under S. flavinotae Girault.

Review of the family Rotoitidae (Hymenoptera: Chalcidoidea), with description of a new genus and species from Chile

A new genus and species of Rotoitidae, Chiloe micropteron Gibson and Huber, is described from females and one male from Chile. The taxon is the second known genus and species, and the male is the only one known for the family. Scanning electron micrographs illustrate external and internal structure of C. micropteron females, and external structure of Rotoita basalis

Braconid parasitoids (Hymenoptera: Braconidae) of Nearctic Choristoneura species (Lepidoptera: Tortricidae), with a summary of other parasitoid families attacking Choristoneura

Abstract Illustrated identification keys are given for the superfamilies/families of insect parasitoids and the subfamilies, genera, and species of Braconidae reared from species of Choristoneura Lederer in the Nearctic Region. Goniozus floridanus (Ashmead) (Chrysidoidea: Bethylidae) represents the third superfamily of Hymenoptera, and Colpoclypeus florus (Walker) (Hymenoptera: Eulophidae) is added to the list of Chalcidoidea recorded from Choristoneura. Fifty species of Braconidae in 18 genera and 9 subfamilies are recorded parasitizing 11 Choristoneura species; almost half belong to the Microgastrinae. Eight braconids (16%) were found for the first time as parasitoids of Choristoneura. The first host record is given for Oncophanes californicus (Ashmead) (Hormiinae). Known insect parasitoids of Choristoneura spp. in the Nearctic Region include 230 species in 106 genera, about 75% of which attack only 1 or 2 Choristoneura species each. An additional 36 species are considered incorrectly associated with Choristoneura, an error rate of 14%. The Banchinae (Ichneumonidae, especially Glypta Gravenhorst), Pimplinae (Ichneumonidae), and Microgastrinae (Braconidae) made up the greatest proportion of parasitoids. No parasitoids have yet been recorded from five Nearctic Choristoneura species.

World reclassification of the Gonatocerus group of genera (Hymenoptera: Mymaridae).

The 400+ nominal species of the worldwide genus Gonatocerus Nees are reclassified into 14 genera that are placed in Gonatocerini, which is defined by three putative autapomorphies. A key to the 13 extant genera of Gonatocerini is given, based on females. Five previously described genus-group taxa are recognized: Cosmocomoidea Howard stat. rev. (= ater group, of authors), Gahanopsis Ogloblin stat. rev. (= deficiens group, of authors), Gastrogonatocerus Ogloblin stat. n. (= membraciphagus group, of authors), Gonatocerus (= sulphuripes group, of authors), and Lymaenon Walker stat. rev. (= litoralis group, of authors). One new fossil genus, Archigonatocerus Huber gen. n., with two fossil species, A. balticus Huber sp. n., and A. longivena Huber sp. n. and one fossil species in Gonatocerus, G. janzeni Huber sp. n., are described, all from Baltic amber from the Eocene epoch. Eight new extant genera and 16 new extant species are described and their species keyed: Cosmocomopsis Huber gen. n., with C. flopsis Huber sp. n. and C. mopsis Huber sp. n.; Heptagonatocerus Huber gen. n., with H. madagascarensis Huber sp. n., H. magnificus Huber sp. n., H. parvus Huber sp. n., and H. pulchellus Huber sp. n.; Krateriske Huber gen. n., with K. ecuadorensis Huber sp. n., K. guianensis Huber sp. n., and K. peruensis Huber sp. n.; Octomicromeris Huber gen. n., with O. compacta Huber sp. n. and O. brevis Huber sp. n.; Pro-gonatocerus Huber gen. n., with P. albiclava Huber sp. n. and P. brunneiclava Huber sp. n; Tanyxiphium Huber gen. n., with T. breviovipositor Huber sp. n., T. longissimum Huber sp. n., and T. seychellense Huber sp. n. Yoshimotoana Huber gen. n. (= masneri group, of authors) with one included species and Zeyanus Huber, gen. n. (= asulcifrons group, of authors) with 9 included species. Keys to the species of seven genera: Archigonatocerus, Cosmocomopsis, Heptagonatocerus, Krateriske, Octomicromeris, Progonatocerus, and Tanyxiphium are provided. Information for each nominal species catalogued includes the original reference, kind, sex and depository of primary type, and subsequent references that include relevant previous generic combinations, if applicable. The type locality is given, based on original descriptions or, where necessary, subsequent publications that provide clarification on the collection locality. Two new synonyms are proposed: Gonatocerus similis Gupta & Poorani, 2008, syn. n. under G. bialbifuniculatus Subba Rao, 1989; and Gonatocerus hispaniolus Triapitsyn & Huber, 2010, syn. n. under G. masneri Yoshimoto, 1990. Among the species, 245 new combinations are proposed: 82 in Cosmocomoidea, 1 in Cosmocomopsis, 4 in Gahanopsis, 8 in Gastrogonatocerus, 3 in Gonatocerus, 135 in Lymaenon, 2 in Tanyxiphium, 1 in Yoshimotoana, and 9 in Zeyanus. Revived combinations are proposed for Twelve species: 1 in Cosmocomoidea, 1 in Gahanopsis, 2 in Gonatocerus, and 8 in Lymaenon. The 410 nominal species group names are catalogued under their currently accepted genus and also listed alphabetically in an appendix. A tentative generic phylogeny is proposed.

Review of Anaphes Haliday (Hymenoptera: Mymaridae) with key to species in Europe and a world catalogue

The Walter Soyka species of Anaphes Haliday are reviewed and placed in context among the remaining world species. An analysis of his descriptions and identification keys is presented, and discussed in light of a broader interpretation of intraspecific variation in Anaphes species than Soyka accepted. An illustrated diagnosis of Anaphes is given and the species in Europe considered to be valid are keyed-14 species in Anaphes (Anaphes) and 15 species in Anaphes (Patasson). The 244 names of world Anaphes are tabulated in various ways and their type localities, if known, are mapped. All available valid names and their synonyms, mostly from among the 155 nominal species described by Soyka, are catalogued, with details of type material and collecting information. A total of 167 synonyms are listed, 17 of which are synonyms proposed by earlier authors and 149 of which are proposed as new synonyms. Lectotypes are designated for Mymar ferreirei Soyka and Yungaburra acutiventris Soyka. Nine nomina dubia, 2 names of fossil species that most likely do not belong to Anaphes, 3 unavailable names and 20 species transferred to other genera are listed separately; among the latter, Anagrus foersteri (Ratzeburg) is transferred to Erythmelus Enock as E. foersteri (Ratzeburg), comb. n. Host records published from 1985-2015 are tabulated; most are from the literature but a few are from unpublished records found on slide mounted Anaphes specimens in various collections, mostly in Europe. The merits of classifying the available names of nominal species into an earlier classification with subgenera Anaphes (Anaphes) and Anaphes (Patasson) instead a later classification consisting of species groups within Anaphes (Anaphes) and Anaphes (Yungaburra) are discussed; the earlier classification is preferred.

The genus Ooctonus Haliday (Hymenoptera: Mymaridae) in the Afrotropical Region, with comments on other southern hemisphere species

Three species of Ooctonus (Hymenoptera: Mymaridae) are described from South Africa: O. albiclavus Huber, sp. n., O. capensis Huber, sp. n., and O. infuscatus Huber, sp. n. They represent the first records of Ooctonus from the Afrotropical Region and the first described species of Ooctonus native to the southern hemisphere. The only previously named Ooctonus from Africa (Madagascar), O. sevae Risbec, was transferred recently to Gonatocerus. A lectotype and paralectotypes are designated here for the slide-mounted and two card-mounted syntypes, respectively, of this species. One species in New Zealand, Ooctonus vulgatus Haliday, is an accidental introduction from the northern hemisphere. Online interactive keys to the South African species are available at: http://www.waspweb.org/Chalcidoidea/Mymaridae/Keys/index.htm

Two genera of Mymaridae (Hymenoptera) new to Africa, a remarkable new species of Anaphes and new generic synonymy

Abstract Bakkendorfia Mathot, syn. n. is placed in synonymy under Cleruchus Enock and its only described species transferred as Cleruchus musangae (Mathot), comb. n. Anaphes quinquearticulatus Huber & Triapitsyn, sp. n. is described; it is the only known Anaphes Haliday species with a 5-segmented funicle in females. Two genera are reported for the first time from the Afrotropical region and two species are described: Paranaphoidea (Idiocentrus) africana Huber & Triapitsyn, sp. n., and Allanagrus occidentalis Huber & Triapitsyn, sp. n.

Redescription of Chrysoctonus and description of Chrysoctonoides (Hymenoptera, Mymaridae), a new genus from the Australian Region

Abstract Chrysoctonoides longisetosa Huber & Triapitsyn (Hymenoptera: Mymaridae), gen. n. and sp. n., is described from Australia. It is compared with the related genus Chrysoctonus, known from Africa and the New World. Myrmecomymar Yoshimoto, syn. n., is synonymized under Chrysoctonus Mathot and its type species is transferred to Chrysoctonus as Chrysoctonus masneri (Yoshimoto), comb. n.