Chromosome-Aware Phylogenomics of Assassin Bugs (Hemiptera: Reduvioidea) Elucidates Ancient Gene Conflict.

Though the phylogenetic signal of loci on sex chromosomes can differ from those on autosomes, chromosomal-level genome assemblies for nonvertebrates are still relatively scarce and conservation of chromosomal gene content across deep phylogenetic scales has therefore remained largely unexplored. We here assemble a uniquely large and diverse set of samples (17 anchored hybrid enrichment, 24 RNA-seq, and 70 whole-genome sequencing samples of variable depth) for the medically important assassin bugs (Reduvioidea). We assess the performance of genes based on multiple features (e.g., nucleotide vs. amino acid, nuclear vs. mitochondrial, and autosomal vs. X chromosomal) and employ different methods (concatenation and coalescence analyses) to reconstruct the unresolved phylogeny of this diverse (∼7,000 spp.) and old (>180 Ma) group. Our results show that genes on the X chromosome are more likely to have discordant phylogenies than those on autosomes. We find that the X chromosome conflict is driven by high gene substitution rates that impact the accuracy of phylogenetic inference. However, gene tree clustering showed strong conflict even after discounting variable third codon positions. Alternative topologies were not particularly enriched for sex chromosome loci, but spread across the genome. We conclude that binning genes to autosomal or sex chromosomes may result in a more accurate picture of the complex evolutionary history of a clade.

Hiding in Plain Sight: An Abundant and Widespread North American Horse Fly (Diptera: Tabanidae) in the Tabanus sulcifrons Group, Tabanus variegatus Fabricius, Redescribed.

Tabanus variegatus F. 1805 has been called by the name Tabanus sulcifronsMacquart 1855 for over 80 yr; T. variegatus is one of the most common large horse flies attacking livestock in much of the southeastern U.S. Morphological, ecological, and molecular evidence indicates that T. variegatus is a distinct species, and we redescribe the female and describe the male. The Fabricius holotype, heavily damaged after over nearly 220 yr, is nevertheless taxonomically sound. Morphology (size, color, palp shape, and r5 wing cell shape) can usually distinguish T. variegatus from T. sulcifrons, but some specimens remain difficult to separate, especially in and west of the Mississippi River Valley. Using geometric morphometric analyses of the wing vein arrangement and palp shape the two species are significantly different. The wings of T. variegatus females also have more microsetae and sometimes a "frosty" appearance. Where they are common and sympatric, as in eastern Tennessee, they are temporally separated such that T. variegatus flies later (August-October) than T. sulcifrons (June-August), minimizing opportunity for gene flow. Museum specimens allow the approximate range of T. variegatus to be compared with that of T. sulcifrons s.l.; T. variegatus is particularly abundant from the coast of the Carolinas and Georgia east to central Tennessee and south to about central Alabama. DNA evidence (COI gene) recovers T. variegatus and T. sulcifrons s.s. in separate clades. Further studies on the T. sulcifrons complex are needed to fully resolve the range of both species, assess the degree of genetic substructuring, and examine relationships with other members of the T. sulcifrons complex.

Reared microgastrine wasps (Hymenoptera: Braconidae) from Yanayacu Biological Station and environs (Napo Province, Ecuador): diversity and host specialization.

The microgastrine braconid wasps recovered up through 2007 by the NSF-sponsored rearing project "Caterpillars and Parasitoids of the Eastern Andes in Ecuador" are summarized in terms of their host specialization and faunistic uniqueness. Two hundred fifty eight rearings of caterpillars resulted in records of Microgastrinae, distributed among 14 genera (Apanteles Förster, Choeras Mason, Cotesia Cameron, Diolcogaster Ashmead, Distatrix Mason, Dolichogenidea Viereck, Exix Mason, Glyptapanteles Ashmead, Hypomicrogaster Ashmead, Papanteles Mason, Parapanteles Ashmead, Protapanteles Ashmead, Sathon Mason and Venanus Mason). Eleven records of hyperparasitoids of Microgastrinae are also summarized; Mesochorus Gravenhorst (Ichneumonidae) and Perilampidae are both recorded. The results are compared to those recovered by surveys in other parts of the world, especially by the Janzen-Hallwachs survey of the Area de Conservación Guanacaste (ACG) in Costa Rica. An annotated list of microgastrine genera not yet recorded at Yanayacu, but which we expect to eventually find there based on extrapolation from their known geographic distributions, is provided.