UC Davis

Abstracts

Chapter 1 The Nearctic species of Saropogon Loew, 1847 north of Mexico are reviewed, with 19 species recognized and one described as new: Saropogon pyrodes sp. nov. from Arizona. This previously recognized new species has awaited description since its first collection in 1964. Only after a community scientist posted photographs taken in nature to an online database did its description become a priority. All species of Saropogon occurring in the Nearctic Region north of the Mexican border have been reexamined. Photographs and diagnoses of all species are provided with a distribution map of the included specimens studied. An updated key to the Nearctic species north of Mexico is provided. Finally, the need for a review of the diverse Mexican fauna is expressed.

Chapter 2 More than 3,400 Asilidae specimens with their associated prey have been specimen-level databased, by examining 15 natural history collections in the USA. The orders of arthropods preyed upon are, in order of representation, Hymenoptera, Diptera, Coleoptera, Orthoptera, Blattodea, Odonata, Araneae, Neuroptera, Thysanoptera, Siphonaptera, and Trichoptera. Asilidae genera with sufficient data to warrant special attention are: Asilinae (Efferia, Mallophora, Megaphorus, Proctacanthus, Promachus, and Triorla), Brachyrhopalinae (Ceraturus, Cyrtopogon, Heteropogon, Holopogon, and Nicocles), Dasypogoninae (Diogmites and Saropogon), Dioctriinae (Dioctria), Laphriinae (Atomosia and Laphria), Leptogastrinae (Leptogaster), Ommatiinae (Ommatius), Stenopogoninae (Callinicus, Microstylum, Ospriocerus, Scleropogon, and Stenopogon), Stichopogoninae (Stichopogon), and Trigonomiminae (Holcocephala). Most Asilidae prefer a generalist or polyphagous diet consisting of only arthropod prey. However, several genera appear oligophagous – Ceraturgus on Coleoptera, Diogmites on Hymenoptera, Laphria on Lampyridae, Mallophora on Apidae, Megaphorus on Hymenoptera, Nicocles on Diptera, Ospriocerus on Meloidae, Promachus on Apidae, Saropogon on Hymenoptera, and Stichopogon on Diptera. This dataset also supports previous findings that female asilid predators outnumbered males in a 1.5 to 1 ratio.

Chapter 3Assassin flies (Diptera: Asilidae) are a diverse family that plays an essential ecological role as top aerial and venomous predators. Little is known about the evolution of their predatory habits. This study provides a novel phylogenetic hypothesis of Asilidae along with prey preference and ancestral state reconstruction in a maximum likelihood framework. This study is based on 176 assassin fly species, 35 Asiloidea outgroup species, prey preference data accumulated from literature and museum collections, and approximately 7,913 bp of nuclear DNA from five genes (18S and 28S rDNA, AATS, CAD, and EF-1alpha protein-encoding DNA) and mitochondrial DNA from one gene (COI). Of the 12 asilid subfamilies included in the analysis the monophyly of six was supported. We used ancestral state reconstruction and stochastic character mapping to test whether a polyphagous arthropod predator is the ancestral state for Asilidae. Assassin flies are polyphagous arthropod predators, with specialized arthropod prey preferences evolving 20 independently across the Asilidae phylogeny.