Lloyd Knutson

Key Aspects of the Biology of Snail-Killing Sciomyzidae Flies

The biology of snail-killing flies (Diptera: Sciomyzidae) has been studied intensively over the past half-century, especially over the past decade. Today, sciomyzids are biologically the best-known group of higher Diptera. The overarching research objectives are evaluation of sciomyzids as biocontrols of disease-carrying or agriculturally important snails and slugs and as a paradigm group for the study of the evolution of diverse feeding and associated behaviors in flies. We present reviews and analyses of some key features of particular scientific and societal interest, including behavioral and phenological groups; laboratory experimental studies on behavior and development; population biology, bioindicators, ecosystem service provision, and conservation; phylogenetics, molecular studies, and evolutionary biology; and biocontrol.

Extraordinary feeding behaviour in Diptera Sciomyzidae, snail-killing flies

In the laboratory, the larva of Sepedonella nana, Diptera Sciomyzidae, were only able to develop at the expense of small aquatic oligochets collected in adult habitats. Up till now, larval cycles have been elucidated for 38% of the Sciomyzidae; all these larvae proved to be strict consumers of aquatic or terrestrial molluscs (including slugs). This specific predation was considered as a major distinguishing characteristic of Sciomyzidae among Diptera. The unusual nutritional behaviour of S. nana reported in the present note is in contradiction with well-established prior knowledge. The species presented all the characteristics of the family, particularly the ventral arch sclerite present on the larva cephalopharyngeal skeleton. It was considered as a derived species; this behaviour, probably of secondary type, revealed new nutritional types for Afrotropical Sciomyzidae for which the biology of only five species was elucidated out of about 60 species described.

Review and analysis of information on the biology and morphology of immature stages of robber flies (Diptera: Asilidae).

Recent publications on the immature stages of robber flies (Asilidae) are reviewed and listed for the 14 currently recognized subfamilies (Asilinae, Bathypogoninae, Brachyrhopalinae, Dasypogoninae, Dioctriinae, Laphriinae, Leptogastrinae, Ommatiinae, Phellinae, Stenopogoninae, Stichopogoninae, Tillobromatinae, Trigonomiminae, and Willistonininae). For the Phellinae there are only limited data on the pupal cases, and for the Tillobromatinae there are only limited data on the eggs (potential oviposition site in soil) and pupal cases. The recent literature is compared with pertinent pre-1972 publications.

Biology and Immature Stages of Tetanura pallidiventris, a Parasitoid of Terrestrial Snails (Dipt. Sciomyzidae)

Tetanura pallidiventris (Fallen) (Dipt. Scionyzidae) lives in terrestrial habitats in northern and central Europe, where the larvae feed on snails of the genera Cochlicopa, Discus, and Retinella. Field and laboratory data on the ecology and behaviour of the species are presented. The egg, third-instar cephalopharyngeal skeleton, and puparium are described and figured. The species is distinguished from T. fallenii Hendel, and the systematic position of the genus Tetanura Fallen is discussed.

A New Species of Snail-Killing Fly of the Genus Dictya Meigen from the Delmarva States (Diptera: Sciomyzidae)

Abstract A new species of snail-killing fly, Dictya orthi (Diptera: Sciomyzidae), is described from the Delmarva States (type locality: Virginia. Stafford; Aquia Harbour, Lions Park). Provided are detailed photographs, descriptions of structures of the male terminalia, a generic diagnosis, and a key to species of Dictya from the Delmarva and adjacent states.

Biology of Snail-Killing Flies in Sweden (Dipt., Sciomyzidae)1

The major biological features of 53 of the 70 Swedish species of Sciomyzidae (Diptera: Acalyptratae) are summarized. The larvae are found in many kinds of aquatic and terrestrial habitats, and those of most species are air-breathing, overt, polyphagous predators of aquatic and hygrophilous, non-operculate snails. Larvae of a few species are predators or oligophagous, solitary and internal parasitoids of terrestrial snails, Tetanocera elata attacks slugs, and Antichaeta spp. feed in egg-masses of Lymnaeidae and Succineidae. Knutsonia lineata and certain Renocera spp. are the only insects known to feed obligatorily in bivalve Sphaeriidae.

A taxonomic review of Pelidnoptera Rondani (Diptera: Sciomyzoidea), with discovery of a related new genus and species from Asia.

The genus Pelidnoptera Rondani is taxonomically reviewed based on examination of the type series. Pelidnoptera triangularis , sp.n. from Japan, the Russian Far East and Nepal, and Akebono vernalis , gen. & sp.n. from Japan are described and illustrated. The lectotype of P. leptiformis (Schiner) is designated here based on the examination of syntypes in the Naturhistorisches Museum, Wien.

The Sciomyzidae (Diptera, Acalyptratae) of Israel, with notes on the distribution of the Near East species

Eighteen species of Sciomyzidae are recorded from Israel, all but two for the first time. Three species are described as new: Pherbellia hermonensis. P. pninae, and P. priscillae. Tetanoceraformosa Loew is transferred from Trypetoptera Hendel to Euthycera Latreille. Keys for the identification of the genera of the Near East and for the species in Israel are included, and the heads and wings are illustrated for each Israeli species. Localities in Israel and the general distribution are given for each species. The distribution of Sciomyzidae in the countries around the eastern end of the Mediterranean is summarized in a chart. The sciomyzid fauna of Israel is primarily a subtraction element of the Anatolian fauna. Data on the distribution of Sciomyzidae in the Levant and within Israel are used to suggest that inability of adult Sciomyzidae to cross desert areas is the main reason for the separation of the Palearctic and Ethiopian faunas at their Eastern contacts.

Uses and user community of entomological collections

There are many applications of data associated with insect collections to research and action programs outside the immediate taxonomic community. The development of new classes of users requires a continual re-evaluation of taxonomic capabilities, and the taxonomists, awareness of and potential for meeting the new needs. Certain improvements can be made in the operating procedures of, and in communication between, taxonomists and users. However, increased support for taxonomy is essential if the users needs are to be met.

Seasonal distribution of a relatively rare and a relatively common species of Thecomyia at Belém, Pará, Brazil (Diptera: Sciomyzidae)

O genero neotropical Thecomyia (Sciomyzidae) consiste de quatro especies descritas e onze ainda nao descritas (Steyskal & Knutson em preparacao), sendo a maioria nao muito comum. As especies sao muito proximas e grande numero delas somente pode ser separado com base na genitalia do macho. Somente e conhecida a biologia e uma especie, T. limbata (Wiedermann), que, preferentemente, preda moluscos aquaticos (Abercrombie & Berg, 1975). A analise de registros de coletas de especies relativamente raras e relativamente comuns de Thecomyia (172 especimens do Museu Goeldi coletados em Mocambo, Belem, Para, Brasil) proporcionam informacoes sobre a distribuicao sazonal de especies tropicais e sua relativa abundância. Deste material 160 especimens pertencem a T. longicornis Perty e 12 a Thecomyia sp. n. A primeira foi registrada durante todos os meses do ano, mas a especie nova somente durante junho e dezembro, sugerindo esta ultima uma populacao de adultos anual bimodal.