Jaromír Vaňhara

Thrips (Thysanoptera) identification using artificial neural networks.

We studied the use of a supervised artificial neural network (ANN) model for semi-automated identification of 18 common European species of Thysanoptera from four genera: Aeolothrips Haliday (Aeolothripidae), Chirothrips Haliday, Dendrothrips Uzel, and Limothrips Haliday (all Thripidae). As input data, we entered 17 continuous morphometric and two qualitative two-state characters measured or determined on different parts of the thrips body (head, pronotum, forewing and ovipositor) and the sex. Our experimental data set included 498 thrips specimens. A relatively simple ANN architecture (multilayer perceptrons with a single hidden layer) enabled a 97% correct simultaneous identification of both males and females of all the 18 species in an independent test. This high reliability of classification is promising for a wider application of ANN in the practice of Thysanoptera identification.

Artificial intelligence in pest insect monitoring

Abstract Global problems of hunger and malnutrition induced us to introduce a new tool for semi‐automated pest insect identification and monitoring: an artificial neural network system. Multilayer perceptrons, an artificial intelligence method, seem to be efficient for this purpose. We evaluated 101 European economically important thrips (Thysanoptera) species: extrapolation of the verification test data indicated 95% reliability at least for some taxa analysed. Mainly quantitative morphometric characters, such as head, clavus, wing, ovipositor length and width, formed the input variable computation set in a Trajan neural network simulator. The technique may be combined with digital image analysis.

Larval Morphology and Anatomy of the Parasitoid Exorista larvarum (Diptera: Tachinidae), with an Emphasis on Cephalopharyngeal Skeleton and Digestive Tract

Abstract The endogenous development of the tachinid gregarious larval parasitoid Exorista larvarum L. (Diptera: Tachinidae) has been analyzed in the last larval instar of a factitious host, the wax moth Galleria mellonella L. (Lepidoptera: Pyralidae), with the use of histological techniques and scanning electron microscopy. This study has focused on the parasitoid internal body structures and their changes during the larval development. The first and second instars are enveloped by a host-derived hemocyte capsule attached to the respiratory funnel via a prominent anal hook located between 2 anal lobes. The third instar abandons the respiratory funnel and migrates free in the body cavity of the already dead host. Emphasis is given to the prominent cephalopharyngeal skeleton, highlighting the morphological aspects of its sclerotized as well as non-sclerotized components. In addition to the cephalopharyngeal skeleton, the anterior third of the larval parasitoid body is occupied by large salivary glands, massive proventriculus, and cerebral ganglia. The extensive digestive tract, which occupies the major part of the body, is differentiated into well-marked individual parts. The abdomen is predominantly filled with the extremely long mesenteron that increases in size during the larval development. The whole body is covered by an apparently thin integument, with strong spines that are especially numerous in the anterior and posterior body parts.

Artificial neural networks for fly identification: A case study from the genera Tachina and Ectophasia (Diptera, Tachinidae)

The classification methodology based on morphometric data and supervised artificial neural networks (ANN) was tested on five fly species of the parasitoid genera Tachina and Ectophasia (Diptera, Tachinidae). Objects were initially photographed, then digitalized; consequently the picture was scaled and measured by means of an image analyser. The 16 variables used for classification included length of different wing veins or their parts and width of antennal segments. The sex was found to have some influence on the data and was included in the study as another input variable. Better and reliable classification was obtained when data from both the right and left wings were entered, the data from one wing were however found to be sufficient. The prediction success (correct identification of unknown test samples) varied from 88 to 100% throughout the study depending especially on the number of specimens in the training set. Classification of the studied Diptera species using ANN is possible assuming a sufficiently high number (tens) of specimens of each species is available for the ANN training. The methodology proposed is quite general and can be applied for all biological objects where it is possible to define adequate diagnostic characters and create the appropriate database.

Penetration and encapsulation of the larval endoparasitoid Exorista larvarum (Diptera: Tachinidae) in the factitious host Galleria mellonella (Lepidoptera: Pyralidae)

The tachinid fly Exorista larvarum (L.) (Diptera: Tachinidae) is a polyphagous larval endoparasitoid that deposits its eggs on the host exoskeleton of lepidopteran and tenthredinid larvae. The attachment of larval E. larvarum and the formation of the respiratory funnel were studied during infestation in the last larval instar of the wax moth, Galleria mellonella (L.) (Lepidoptera: Pyralidae). The tachinid larvae burrow through the host integument after hatching, using their robust cephalopharyngeal skeleton, leaving a dark spot at the point of their penetration as a result of host cuticle melanization. Endoparasitoid penetration induces the host cellular defence, resulting in the formation of a haemocyte capsule consisting of multi-cellular sheaths. This enveloping capsule later undergoes melanization, which is mostly obvious towards the posterior part of the endoparasitoid. The endoparasitoid uses the host encapsulation response to build a respiratory funnel from the modified host integument, leading to the host surface. The encapsulated larva remains attached to the respiratory funnel via an anal hook and cuticular spines until fully developed. Additional immunohistochemical analyses were used to study host-parasitoid interactions. Indirect immunofluorescence showed no labelling of potential tachinid antigens and confirmed no effect on the surrounding host tissues. A simulated parasitization with coated polybead microspheres revealed the mortal impact of tachinid antigens to the host. Hosts injected with antigen-coated polybeads died as a consequence of an acute and extensive immunological response to the tachinid antigens and not due to the trauma caused by foreign objects inside their body.

Taxonomic approach to the tachinid flies Dinera carinifrons (Fallén) (Diptera: Tachinidae) and Dinera fuscata Zhang and Shima using molecular and morphometric data.

Abstract Molecular phylogenetic and traditional morphometric methods were applied to examine six Palaearctic taxa of the taxonomically difficult tachinid fly genus Dinera Robineau-Desvoidy (Diptera: Tachinidae), with particular reference to D. carinifrons (Fallén) and D. fuscata Zhang and Shima. Results of a phylogenetic analysis based on the mitochondrial markers 12S and 16S rDNA and multivariate statistical analyses of 19 morphometric characters were used to delimit both species. A lectotype was designated for D. carinifrons to stabilize the nomenclature in the group. Dinera carinifrons has a transpalaearctic distribution and is present in Central Europe, especially in high altitudes of the Alps. It differs from the similar and closely related D. fuscata in that it has a slightly larger body size, a dense greyish microtrichosity on the body, and different head proportions. Dinera fuscata, as delimited here, is widespread in the Palaearctic region, including Europe. Slight differences in both molecular and morphometric characters were found between western (Europe and Iran) and eastern (China and Japan) populations of D. fuscata, which are interpreted as an intraspecific variation. Differential diagnosis between D. carinifrons and D. fuscata is provided in the form of a revised portion of the determination key to the Palaearctic Dinera by Zhang and Shima (2006).

Kesselimyia chandleri n.gen., n.sp. from Czechoslovakia(Diptera: Platypezidae).

Kesselimyia chandleri n.gen., n.sp. is described from material collected in southern Moravia (Havraniky near Znojmo, Czechoslovakia). The larvae and puparia were found in a rotting mushroom of Lepiota sp., 2♂ and 17 ♀ emerged under laboratory conditions. The description of the new species was based mainly on the structure of the male genitalia. Figures of the most important diagnostic characters of the male, female and larvae are provided.

A revision of the species of Evaza Walker described by J.C.H. de Meijere (Diptera, Stratiomyidae, Pachygastrinae)

Six Oriental species of Evaza Walker, 1856 were described by J.C.H. de Meijere in the period between 1911 and 1924. The type specimens are now deposited in the Museum Naturalis (Leiden). All species were redescribed, photographed and their diagnostic characters were defined. Male terminalia of five species with known males were illustrated in detail. The revised species were compared with recently described new species from Oriental China. Additional material belonging to the revised species was recorded for the first time from the following countries: Evaza demeijerei Brunetti, 1923 (= E. pallipes de Meijere, 1916a) and E. discolor de Meijere, 1916a were found in Malaysia, E. javanensis de Meijere 1911 in Singapore, E. kerteszi de Meijere, 1914 in Laos and Malaysia and E. maculifera de Meijere, 1914 in Malaysia, Philippines, Thailand and Vietnam.

Molecular phylogeny of flat‐footed flies (Diptera: Platypezidae): main clades supported by new morphological evidence

The molecular phylogeny of flat‐footed flies is inferred from analysis of DNA sequence data from the five mitochondrial genes 12S, 16S, COI, COII and CytB, and the nuclear gene 28S and discussed with the recent systematics based on morphological features. The Bayesian inference, maximum likelihood and maximum parsimony analyses included 42 species of 18 genera, representing all four extant subfamilies (Microsaniinae, Melanderomyiinae, Callomyiinae and Platypezinae) and all known genera except one (Metaclythia). Representatives of the brachycerous taxa Lonchopteridae, Phoridae, Sciadocerinae (Phoridae) and Opetiidae are used as outgroups, and Lonchoptera was used to root the trees. Our results show Platypezidae consisting of two well‐supported clades, the first with the subfamilies Melanderomyiinae + Callomyiinae and the second formed by subfamily Platypezinae. Genus Microsania was resolved as a separate lineage distant from Platypezidae which clustered with Opetiidae as its sister group, both together forming a sister group to Platypezidae. At the generic level, the genus Agathomyia proved not to be monophyletic in any of the analyses. The species Chydaeopeza tibialis is sister to Agathomyia sexmaculata, and consequently, the genus Chydaeopeza Shatalkin, 1992 is a new junior synonym of Agathomyia Verrall, 1901. Bifurcated setae on legs of adult Platypezidae are documented as a new synapomorphy of the family, exclusive of Microsania. Outstretched wings and only a small overlap of their surfaces at resting position are considered a new synapomorphy for the subfamily Platypezinae. Other phylogenetically important characters defining main clades are documented, and their relevance/validity in phylogenetic studies is discussed. The current systematic concept of Platypezidae is discussed, and new phylogenetic hypotheses are proposed.