DrawWing, a program for numerical description of insect wings

There is usually a pattern of veins on an insect wing. This pattern is species-specific and is used taxonomically. For example, the coordinates of some characteristic points on the wing are used to compare vein patterns. The characteristic points are often vein junctions or vein ends. A tool is presented that enables automatic identification of vein junctions. An image of an insect wing is used to determine the wing outline and veins. The vein skeleton is obtained using a thinning algorithm. Bezier splines are fitted to both the wing outline and the vein skeleton. The splines are saved in an encapsulated postscript file. Another output file in text format contains the coordinates of vein junctions. Both the program and its source code are available under GNU General Public License at [www.cyf-kr.edu.pl/~rotofils/drawwing.html]. The program presented in this paper automatically provides a numerical description of an insect wing. It converts an image of an insect wing to a list of coordinates of vein junctions, and a wing diagram that can be used as an illustration. Coordinates of the vein junctions extracted by the program from wing images were used successfully to discriminate between males of Dolichovespula sylvestris and Dolichovespula saxonica

The Use of Female Wing Measurements for Discrimination of Aedes aegypti (L.) (Diptera: Culicidae) Populations from South Kalimantan

Populations of Aedes aegypti in South Kalimantan, which have been discriminated by their cuticular components, were further studied in search for differences in their wing morphometry. Female mosquitoes were collected from five towns in the province of South Kalimantan, and Cartesian coordinates of terminal and branching points of individual wing were determined. Relative interpoint Euclidean distances were used as variables (characters) in statistical analyses. One-way ANOVA found significantly several different characters (P < 0.01). Stepwise discriminant analysis using these characters selected five discriminators which, by cross validation, could identify female A. aegypti from Barabai and Marabahan with 75 and 77.8% of success rate, respectively. On average, 57.7% of wing specimens were successfully allocated to their original populations. The study revealed differences in wing measurements among populations of A. aegypti in South Kalimantan and confirmed genetic divergence of the species in the province. Key words: Aedes aegypti, wing morphometry, discriminant analysis, identification, discriminatio

Vision for navigation: what can we learn from ants?

The visual systems of all animals are used to provide information that can guide behaviour. In some cases insects demonstrate particularly impressive visually-guided behaviour and then we might reasonably ask how the low-resolution vision and limited neural resources of insects are tuned to particular behavioural strategies. Such questions are of interest to both biologists and to engineers seeking to emulate insectlevel performance with lightweight hardware. One behaviour that insects share with many animals is the use of learnt visual information for navigation. Desert ants, in particular, are expert visual navigators. Across their foraging life, ants can learn long idiosyncratic foraging routes. What's more, these routes are learnt quickly and the visual cues that define them can be implemented for guidance independently of other social or personal information. Here we review the style of visual navigation in solitary foraging ants and consider the physiological mechanisms that underpin it. Our perspective is to consider that robust navigation comes from the optimal interaction between behavioural strategy, visual mechanisms and neural hardware.We consider each of these in turn, highlighting the value of ant-like mechanisms in biomimetic endeavours

Host location in a specialist parasitoid wasp via olfactory cues – a physiological, behavioural and morphological study

For successful host location, parasitoids are thought to have evolved different strategies to filter relevant olfactory cues which indicate the presence of the host. Because of their versatility in their ecology and behaviour, as well as their fine tuned olfactory system to volatile compounds of the host and host plant, they have gained increasing recognition as model organisms to study learning and behaviour in an adaptive ecological context. However, neural and cellular mechanisms of olfactory detection and processing in parasitoids are mainly unknown.In this thesis physiological, behavioural and morphological experiments were used to determine neural and behavioural mechanisms of host location via olfactory cues in the specialist parasitoid Cotesia vestalis. C. vestalis showed significant antennal responses to a range of odour compounds. Behavioural experiments, however, have demonstrated that only the herbivore-induced plant volatile linalool attracts C. vestalis males and females, but 1-nonanol has a repulsive effect on females. A morphological study of the antennal lobe, the first brain area where olfactory information is processed, revealed 40 ordinary glomeruli in both males and females. In addition, a complex of 2-3 enlarged glomeruli (MGC) was found in males. The courtship behaviour observed in males and the MGC suggest that males could use sex pheromones to locate females. Finally, calcium imaging studies showed glomerular activity to olfactory stimulation in bees but not in parasitoids. In conclusion, the degree of host specialisation in C. vestalis appears to influence olfactory learning in males and females, which favours learning of volatiles related to its host and host plant, as well as the morphological organisation of the antennal lobe. Larger, fewer and possibly specialised glomeruli could enhance processing of odour cues which are important for this parasitoid

Algorithms to automatically quantify the geometric similarity of anatomical surfaces

We describe new approaches for distances between pairs of 2-dimensional surfaces (embedded in 3-dimensional space) that use local structures and global information contained in inter-structure geometric relationships. We present algorithms to automatically determine these distances as well as geometric correspondences. This is motivated by the aspiration of students of natural science to understand the continuity of form that unites the diversity of life. At present, scientists using physical traits to study evolutionary relationships among living and extinct animals analyze data extracted from carefully defined anatomical correspondence points (landmarks). Identifying and recording these landmarks is time consuming and can be done accurately only by trained morphologists. This renders these studies inaccessible to non-morphologists, and causes phenomics to lag behind genomics in elucidating evolutionary patterns. Unlike other algorithms presented for morphological correspondences our approach does not require any preliminary marking of special features or landmarks by the user. It also differs from other seminal work in computational geometry in that our algorithms are polynomial in nature and thus faster, making pairwise comparisons feasible for significantly larger numbers of digitized surfaces. We illustrate our approach using three datasets representing teeth and different bones of primates and humans, and show that it leads to highly accurate results.Comment: Changes with respect to v1, v2: an Erratum was added, correcting the references for one of the three datasets. Note that the datasets and code for this paper can be obtained from the Data Conservancy (see Download column on v1, v2

Automatic Identification of Morphometric Landmarks in Digital Images

We present an automated system for the analysis of edge based structure for use in morphomet-ric studies. The current work takes a grey level image of a Drosophila wing as input and extracts the coordinates of 15 landmarks. The proposed method extracts the ridges (linear features such as wing veins) using the knowledge of their known grey level profile and the noise character

Chemical ecology and olfactory behaviour of an aphid parasitoid and a lacewing predator

Female parasitoid (Aphidius colemani) olfactory preference was consistently biased in olfactometer experiments towards the Brassica cultivar on which it was reared when offered other Brassica cultivars as alternatives using either whole plants or detached leaves. Using gas chromatography, differences could be detected in the volatile composition of whole plants and detached leaves of five Brassica cultivars and the volatiles responsible for the fine distinctions the wasps are capable of making between plant cultivars are suggested. By subjecting female wasps to olfactory conditioning protocols, studies were carried out to understand the learning process for individual green leaf volatiles (6-carbon molecules), known to elicit behavioural responses in many insect species. Wasps were exposed to primary alcohols with differing carbon chain lengths in conjunction with aphids in an attempt to condition the wasps to the alcohols. When tested for learning, wasps changed their responses towards alcohols with molecules consisting of between 5 and 6 carbon atoms. The effect of cold temperature on olfactory preference was also investigated. After treating females at 0 °C for 0.5 h or longer, preference for the odour of the Brassica cultivar on which they were reared was lost for one hour after the cold treatment had finished, after which, the preference returned. However, when Brassica or unencountered plant odours were presented with clean air as the alternative choice, females could discern plant odour even immediately after the cold treatment. This suggests that the olfactory and locomotive systems were not altered by cold, whereas responses arising from learning-produced memories appear to have been inhibited temporarily and revealing underlying innate responses. The results indicate that temperature treatments could offer the possibility of dissecting innate and learnt behaviours in these parasitic wasps. The importance of controlling humidity arising from odour choices in olfactometers is also observed. In addition to assessing the parasitoid’s behaviour, various aspects of the role that neomatatabiol, a chemical compound closely related to aphid sex pheromone was investigated in relation to its role in the chemical ecology of the green lacewing Peyerimhoffina gracilis

The exchangeability of shape

<p>Abstract</p> <p>Background</p> <p>Landmark based geometric morphometrics (GM) allows the quantitative comparison of organismal shapes. When applied to systematics, it is able to score shape changes which often are undetectable by traditional morphological studies and even by classical morphometric approaches. It has thus become a fast and low cost candidate to identify cryptic species. Due to inherent mathematical properties, shape variables derived from one set of coordinates cannot be compared with shape variables derived from another set. Raw coordinates which produce these shape variables could be used for data exchange, however they contain measurement error. The latter may represent a significant obstacle when the objective is to distinguish very similar species.</p> <p>Results</p> <p>We show here that a single user derived dataset produces much less classification error than a multiple one. The question then becomes how to circumvent the lack of exchangeability of shape variables while preserving a single user dataset. A solution to this question could lead to the creation of a relatively fast and inexpensive systematic tool adapted for the recognition of cryptic species.</p> <p>Conclusions</p> <p>To preserve both exchangeability of shape and a single user derived dataset, our suggestion is to create a free access bank of reference images from which one can produce raw coordinates and use them for comparison with external specimens. Thus, we propose an alternative geometric descriptive system that separates 2-D data gathering and analyzes.</p

Impacts des polluants métalliques sur l'abeille : de la colonie au cerveau

Les abeilles sont des pollinisateurs essentiels. Une pléthore de facteurs de stress environnementaux, tels que les produits agrochimiques, a été identifiée comme contribuant à leur déclin mondial. En particulier, ces facteurs de stress altèrent les processus cognitifs impliqués dans les comportements fondamentaux. Jusqu'à présent, cependant, on ne sait pratiquement rien de l'impact de l'exposition à des métaux lourds, dont la toxicité est avérée chez de nombreux organismes. Pourtant, leurs émissions mondiales résultant des activités humaines ont élevé leurs concentrations bien au-dessus des niveaux naturels dans l'air, le sol, l'eau et la flore, exposant ainsi les abeilles à tous les stades de leur vie. Le but de ma thèse était d'examiner les effets de la pollution métallique sur l'abeille domestique en utilisant une approche multi-échelle, du cerveau à la colonie, en laboratoire et sur le terrain. J'ai d'abord observé que les abeilles exposées à une gamme de concentrations de trois métaux communs (arsenic, plomb et zinc) en laboratoire étaient incapables de percevoir et éviter des concentrations usuelles, néanmoins nocives, de ces métaux dans leur nourriture. J'ai ensuite exposé de façon chronique des colonies à des concentrations réalistes de plomb dans la nourriture et démontré que la consommation de ce métal altérait la cognition et le développement morphologique des abeilles. Comme les polluants métalliques se trouvent souvent dans des mélanges complexes dans l'environnement, j'ai exploré l'effet des cocktails de métaux, montrant que l'exposition au plomb, à l'arsenic ou au cuivre seul était suffisante pour ralentir l'apprentissage et perturber le rappel de la mémoire, et que les combinaisons de ces métaux induisaient des effets négatifs additifs sur ces deux processus cognitifs. J'ai finalement étudié l'impact de l'exposition naturelle aux polluants métalliques dans un environnement contaminé, en collectant des abeilles à proximité d'une ancienne mine d'or, et montré que les individus des populations les plus exposées aux métaux présentaient des capacités d'apprentissage et de mémoire plus faibles, et des altérations de leur développement conduisant à une réduction de la taille de leur cerveau. Une analyse plus systématique des abeilles non exposées a révélé une relation entre la taille de la tête, la morphométrie du cerveau et les performances d'apprentissage dans différentes tâches comportementales, suggérant que l'exposition aux polluants métalliques amplifie ces variations naturelles. Ainsi, mes résultats suggèrent que les abeilles domestiques sont incapables d'éviter l'exposition à des concentrations réalistes de métaux qui sont préjudiciables au développement et aux fonctions cognitives, et appellent à une révision des niveaux environnementaux considérés comme "sûrs". Ma thèse est la première analyse intégrée de l'impact de plusieurs polluants métalliques sur la cognition, la morphologie et l'organisation cérébrale chez l'abeille, et vise à encourager de nouvelles études sur la contribution de la pollution métallique dans le déclin signalé des abeilles, et plus généralement, des insectes.Honey bees are crucial pollinators. A plethora of environmental stressors, such as agrochemicals, have been identified as contributors to their global decline. Especially, these stressors impair cognitive processes involved in fundamental behaviours. So far however, virtually nothing is known about the impact of metal pollutants, despite their known toxicity to many organisms. Their worldwide emissions resulting from human activities have elevated their concentrations far above natural baselines in the air, soil, water and flora, exposing bees at all life stages. The aim of my thesis was to examine the effects of metallic pollution on honey bees using a multiscale approach, from brain to colonies, in laboratory and field conditions. I first observed that bees exposed to a range of concentrations of three common metals (arsenic, lead and zinc) in the laboratory were unable to perceive and avoid, low, yet harmful, field-realistic concentrations of those metals in their food. I then chronically exposed colonies to field-realistic concentrations of lead in food and demonstrated that consumption of this metal impaired bee cognition and morphological development, leading to smaller adult bees. As metal pollutants are often found in complex mixtures in the environment, I explored the effect of cocktails of metals, showing that exposure to lead, arsenic or copper alone was sufficient to slow down learning and disrupt memory retrieval, and that combinations of these metals induced additive negative effects on both cognitive processes. I finally investigated the impact of natural exposure to metal pollutants in a contaminated environment, by collecting bees in the vicinity of a former gold mine, and showed that individuals from populations most exposed to metals exhibited lower learning and memory abilities, and development impairments conducing to reduced brain size. A more systematic analysis of unexposed bees revealed a relationship between head size, brain morphometrics and learning performances in different behavioural tasks, suggesting that exposure to metal pollutants magnifies these natural variations. Hence, altogether, my results suggest that honey bees are unable to avoid exposure to field-realistic concentrations of metals that are detrimental to development and cognitive functions; and call for a revision of the environmental levels considered as 'safe'. My thesis is the first integrated analysis of the impact of several metal pollutants on bee cognition, morphology and brain structure, and should encourage further studies on the contribution of metal pollution in the reported decline of honey bees, and more generally, of insects

Sensory to motor transformation during innate and adaptive behavior in the cockroach

Animal behavior is the result of processing and integrating various internal and external information. It can be highly flexible and vary between individuals. In insects, the mushroom body output region is an essential higher-order brain area in this process. Integration of various sensory and internal information takes place here as well as memory formation. To investigate adaptive behavior, we established classical and operant conditioning paradigms with a focus on inter-individual differences: American cockroaches were trained harnessed as well as freely moving. To gain insight into the transformation from sensory input to motor output behind innate and adaptive behavior, we established an extracellular recording setup including different sensory stimulators: 1) We simultaneously recorded mushroom body output neurons (MBONs) and initial feeding behavior in single animals during odor stimulation and 2) we recorded MBON responses to different sensory modalities. On the behavioral level, cockroaches were successful in memory formation across different paradigms and sensory modalities. Inter-individual differences regarding their cognitive abilities were discovered. Simultaneous neuronal and behavioral recordings revealed a correlation between MBON and feeding responses to food odors, which allowed for prediction of the behavior. Furthermore, neuronal recordings demonstrated that MBONs encode stimulus on- and off-responses, show adaptation during rapid successive stimulation and differ in response latencies to different sensory modalities. Our results strengthen the idea that the mushroom body output region is not only important for memory formation. In addition, it is crucial for the integration as well as categorization of different sensory modalities. Moreover, it is involved in the sensory to motor transformation. Combining the successfully established behavioral and electrophysiological setups builds a solid base to investigate the role of MBONs in memory formation with high temporal resolution and with regard to inter-individual differences