Ryszard Szadziewski

Phylogeny of the infraorder Culicomorpha (Diptera: Nematocera) based on 28S RNA gene sequences

Phylogenetic relationships between the families of the infraorder Culicomorpha were investigated by using partial 28S ribosomal RNA gene sequences. All families traditionally placed in this infraorder were investigated and confirmed as clades. On the other hand, some of the morphological relationships between these families were found to be in disagreement with phylogenies based on molecular characters. Our results did not support the generally accepted division of the Culicomorpha into two superfamilies, the Culicoidea (Culicidae + Corethrellidae + Chaoboridae + Dixidae) and the Chironomoidea (Chironomidae + Ceratopogonidae + Simuliidae + Thaumaleidae). Precisely, if the sister‐group relationship between Culicidae, Chaoboridae and Corethrellidae was clearly confirmed, the Dixidae, traditionally considered as closely related to these two families, were not placed close to them on our trees. On the other hand, strong evidence was found for grouping together the Simuliidae and the Thaumaleidae, in spite of the cytological and morphological differences between these two families. The position of the Ceratopogonidae was uncertain, and the Chironomidae appeared as a possible sister group to the rest of Culicomorpha. The phylogenetic positions of the groups characterized by feeding on vertebrate blood or insect haemolymph (the Culicidae, Chaoboridae, Ceratopogonidae and Simuliidae) suggest that haematophagy has appeared at least twice in the evolution of Culicomorpha.

Composition and antimicrobial activity of fatty acids detected in the hygroscopic secretion collected from the secretory setae of larvae of the biting midge Forcipomyia nigra (Diptera: Ceratopogonidae)

The hygroscopic secretion produced by the secretory setae of terrestrial larvae of the biting midge Forcipomyia nigra (Winnertz) was analysed using gas chromatography coupled with mass spectrometry (GC-MS). The viscous secretion is stored at the top of each seta and absorbs water from moist air. GC-MS analyses (four independent tests) showed that the secretion contained 12 free fatty acids, the most abundant of which were oleic (18:1), palmitic (16:0), palmitoleic (16:1) and linoleic (18:2). Other acids identified were valeric (5:0), enanthic (7:0), caprylic (8:0), pelargonic (9:0), capric (10:0), lauric (12:0), myristic (14:0) and stearic (18:0). Two other compounds, glycerol and pyroglutamic acid, were also found. The antibacterial activity of the fatty acids and pyroglutamic acid was tested using the agar disc diffusion method and targeted Gram positive (Bacillus cereus, Bacillus subtilis, Enterococcus faecalis) and Gram negative bacterial strains (Citrobacter freundii, Pseudomonas aeruginosa, Pseudomonas fluorescens). The antifungal activity was tested by determining minimal inhibitory concentration (MIC) of examined compounds. Fatty acids were tested against enthomopathogenic fungi (Paecilomyces lilacinus, Paecilomyces fumosoroseus, Lecanicillium lecanii, Metarhizium anisopliae, Beauveria bassiana (Tve-N39), Beauveria bassiana (Dv-1/07)). The most effective acids against bacterial and fungal growth were C(9:0), C(10:0) and C(16:1), whereas C(14:0), C(16:0,) C(18:0) and C(18:1) demonstrated rather poor antifungal activity and did not inhibit the growth of bacteria. The antimicrobial assay investigated mixtures of fatty and pyroglutamic acids (corresponding to the results of each GC-MS test): they were found to be active against almost all the bacteria except P. fluorescens and also demonstrated certain fungistatic activity against enthomopathogenic fungi. The hygroscopic secretion facilitates cuticular respiration and plays an important role in the antimicrobial protection of F. nigra larvae living in moist terrestrial habitats.

Biting midges (Diptera:Ceratopogonidae) in Eocene baltic amber from the Rovno region (Ukraine)

Biting midges (Diptera: Ceratopogonidae) in Eocene Baltic amber from the Rovno region (Ukraine) The paper presents the results of an examination of 714 biting midges (Diptera: Ceratopogonidae) preserved in Baltic amber from the Rovno deposits in Ukraine. A new species - Leptoconops rovnensis sp. n. - is described and illustrated. 29 of the fossil species reported here have already been described from other deposits of Baltic amber: 26 of these were also found in amber from the Gulf of Gdańsk and 18 in amber from Bitterfeld (Saxony). The most common genera of biting midges in Ukrainian amber are also found in amber from Bitterfeld and the Gulf of Gdańsk, and with very much the same frequencies. The results indicate that the faunas of Ceratopogonidae enclosed in amber from Rovno, Bitterfeld and the Baltic are very similar, showing that they inhabited similar palaeoenvironments in the same palaeogeographic region.

Biting Midges (Diptera: Ceratopogonidae) from Burmese amber, Myanmar

Synopsis Four new species in the extant genera Austroconops Wirth & Lee and Leptoconops Skuse are described from Burmese amber: Austroconops asiaticus, Leptoconops burmiticus, L. myanmaricus and L. rossi. Johannsenomyia swinhoei Cockerell is redescribed and assigned to the extinct genus Atriculicoides Remm, which is treated as an indicator group characteristic of the Cretaceous period.

Biting Midges (Diptera: Ceratopogonidae) from Cambay Amber Indicate that the Eocene Fauna of the Indian Subcontinent Was Not Isolated

India’s unique and highly diverse biota combined with its unique geodynamical history has generated significant interest in the patterns and processes that have shaped the current distribution of India’s flora and fauna and their biogeographical relationships. Fifty four million year old Cambay amber from northwestern India provides the opportunity to address questions relating to endemism and biogeographic history by studying fossil insects. Within the present study seven extant and three fossil genera of biting midges are recorded from Cambay amber and five new species are described: Eohelea indica Stebner & Szadziewski n. sp., Gedanohelea gerdesorum Stebner & Szadziewski n. sp., Meunierohelea cambayana Stebner & Szadziewski n. sp., Meunierohelea borkenti Stebner & Szadziewski n. sp., and Meunierohelea orientalis Stebner & Szadziewski n. sp. Fossils of species in the genera Leptoconops Skuse, 1889, Forcipomyia Meigen, 1818, Brachypogon Kieffer, 1899, Stilobezzia Kieffer, 1911, Serromyia Meigen, 1818, and Mantohelea Szadziewski, 1988 are recorded without formal description. Furthermore, one fossil belonging to the genus Camptopterohelea Wirth & Hubert, 1960 is included in the present study. Our study reveals faunal links among Ceratopogonidae from Cambay amber and contemporaneous amber from Fushun, China, Eocene Baltic amber from Europe, as well as the modern Australasian and the Oriental regions. These findings imply that faunal exchange between Europe, Asia and India took place before the formation of Cambay amber in the early Eocene.

Sensilla coeloconica ringed by microtrichia in host-seeking biting midges.

The distribution and morphology of antennal sensilla coeloconica in parasitic and predaceous biting midges were studied in females of Forcipomyia (feeding on the blood of frogs), Atrichopogon (feeding on haemolymph), Austroconops, Culicoides (feeding on the blood of birds and mammals) and Brachypogon (feeding on haemolymph and dissolved tissues of insects) (all: Diptera: Ceratopogonidae). A Lower Cretaceous female of Archiculicoides (Diptera: Ceratopogonidae) from Lebanese amber, which fed on the blood of unknown vertebrates, was also examined. In sensilla coeloconica ringed by microtrichia, the peg is grooved longitudinally and protrudes distinctly from the pit. We suggest that the microtrichia encircling the protruding peg form a structure resembling a picket fence in order to maintain a higher level of humidity, which facilitates the capture and transport of odour molecules through the channels in the peg wall. Sensilla coeloconica ringed by microtrichia function as very effective chemoreceptors in host‐ and prey‐seeking activity. During the evolution of Ceratopogonidae, sensilla coeloconica with a fence of microtrichia have evolved twice in groups feeding on the blood of vertebrates (i.e. in the basal lineage: Lower Cretaceous or earlier) and in the subgenus Lasiohelea of Forcipomyia (Palaeogene). Sensilla coeloconica ringed by microtrichia are described for the first time in the relict genus Austroconops.

REDESCRIPTION OF SIMULIDIUM PRISCUM WESTWOOD AND PSEUDOSIMULIUM HUMIDUM (BRODIE) (INSECTA: DIPTERA: RHAGIONIDAE) FROM THE PURBECK LIMESTONE GROUP (LOWER CRETACEOUS) OF ENGLAND

Synopsis The holotype of Simulidium priscum Westwood, 1854 has been rediscovered in the collections of The Natural History Museum, London. It is a single wing from the Lulworth Formation (Berriasian) of Durlston Bay, Dorset. S. priscum and Pseudosimulium humidum (Brodie 1845) from the Lulworth Formation of Wiltshire are redescribed and placed within the Rhagionidae.

Morphology and histology of secretory setae in terrestrial larvae of biting midges of the genus Forcipomyia (Diptera: Ceratopogonidae).

Apneustic larvae of the genus Forcipomyia possess unique secretory setae located on the dorsal surface along the body in two rows, one pair on each thoracic and abdominal segment and two pairs on the head. Morphological and histological studies of secretory setae in fourth instar larvae of Forcipomyia nigra (Winnertz) and Forcipomyia nigrans Remm indicate they are modified mechanoreceptors (sensilla trichodea) in which the trichogen cell is a glandular cell producing a hygroscopic secretion. The cytoplasm of the glandular trichogen cell fills the lumen of a secretory seta, which shows one or more pores on the apex. The cytoplasm contains numerous microtubules responsible for transportation of proteinaceous vesicles, and an extremely large polyploid nucleus typical of gland cells. The main role of the hygroscopic secretion is to moist the body and thus facilitate cuticular respiration.

Immature stages of two European species of the subgenus Meloehelea (Diptera: Ceratopogonidae), with keys to the European subgenera of Atrichopogon

Larvae and pupae of Atrichopogon winnertzi Goetgebuer and A. oedemerarum StorA are described and illustrated. Larvae of both species are terrestrial and associated with rotting pine wood. Diagnoses are given for all stages. Immature stages of A. oedemerarum are described for the first time. A. meloesugans Kieffer, 1922 is recognized as a junior synonym of A. winnertzi Goetghebuer, 1922. Keys are provided to European subgenera of Atrichopogon based on all stages.

The first records of fossil Corethrellidae (Diptera)

The first fossil Corethrellidae, represented by two male adult Corethrella, are described. One, C. prisca sp. n., is from Saxonian amber collected in East Germany and is of Miocene age (22 Ma). The other, C. nudistyla sp. n., is from Dominican Republic amber and is 15-40 million years old. The family Corethrellidae, because of its phylogenetic position, is presumably of at least Jurassic age. The fossils are typical members of the genus Corethrella and belong to a clade which is the sister group of a single species in New Zealand.