The effect of feeding regime on larval black fly (Diptera: simuliidae) primary head fan ray number

Identification of larval simuliids has always been difficult due to the morphological similarity many species bear to one another. For this reason all characters available have been drawn upon to aid in species identification, including head fan ray number. Even in light of an increasing body of anecdotal reports that head fan ray number is not fixed, it has continued to be used to aid species identification. In the current experiment simuliid larvae were reared under controlled laboratory conditions to last instar in one of three feeding regimes. Out of nine trials, the results of six showed a significant inverse relationship between feeding regime and head fan ray number. In addition to the laboratory experiments, larvae were also collected from the field over the course of the spring and summer, 1994. From these samples significant interspecific and intraspecific variations in head fan ray number were found both spatially and temporally within Algonquin Park. From these data it is concluded that head fan ray number for the species analysed is a developmentally plastic character, which varies in response to food availability. Furthermore, given the extreme variations in head fan ray number found in some species, I recommend that head fan ray number not be used as an aid to identification unless it can be shown to be a fixed character for the species in question.

An investigation into the effects of homopteran honeydew sugars versus floral nectar sugars on black fly longevity, flight performance and digestion /

Floral nectar is thought to be the primary carbohydrate source for most dipteran species. However, it has been shown that black flies (Burgin & Hunter 1997 a,b,c), mosquitoes (Foster 1995; Burkett et al. 1999; Russell & Hunter 2002), deer flies (Magnarelli & Burger 1984; Janzen & Hunter 1998; Ossowski & Hunter 2000), horse flies (Schutz & Gaugler 1989; Hunter & Ossowski 1999) and sand flies (MacVicker et al. 1990; Wallbanks et al. 1990; Cameron et al. 1992, 1995; Schlein & Jacobson 1994, 1999; Hamilton & EI Naiem 2000) feed on homopteran honeydew as well as floral nectar. Prior to 1997 floral nectar was thought to be the main source of carbohydrates for black flies. However, Burgin & Hunter (1 997a) demonstrated that up to 35% of black flies had recently consumed meals of homo pte ran honeydew. This information has necessitated a re-assessment of many life history aspects of black flies. Attempts are being made to examine the effects of nectar versus honeydew on black fly fecundity and parasite transmission (Hazzard 2003). Recently, Stanfield and Hunter (unpublished data) have shown that in female black flies, honeydew sugars produce flights of longer distance and duration than do nectar sugars. This thesis examines two aspects of black fly biology as it relates to sugar meal consumption. First, the effects of honeydew and nectar on black fly longevity are examined. Second, the proximate causation behind longer flight performances in honeydew-fed flies will be examined. The comparison between these two sources is important because nectar is composed of mainly simple sugars (monosaccharides and disaccharides) whereas honeydew is composed of both simple and complex sugars (including trisaccharides and tetrasaccharides ).

Characterization of black fly (Diptera: Simuliidae) silk proteins

Black fly (Simuliidae) silk is produced by the larvae and pharate pupae and is used for anchorage and cocoon production. There exists limited information on simuliid silks, including protein composition and genetic sequences encoding such proteins. The present study aimed to expand what is known about simuliid silks by examining the silks of several simuliid species and by making comparisons to the silk of non-biting midges (Chironomidae). Silk glands were dissected out of larval and pupal simuliids, and protein contents were separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and visualized with silver stain. Protein contents were compared by mass in kilodaltons (kDa) between life stages and among species. Polymerase chain reaction (PCR) was used to expand upon known gene sequence information, and to determine the presence of genes homologous to chironomid silk. SDS-PAGE of cocoons revealed the presence of a 56 kDa and a 67 kDa protein. Silk gland contained as many as 28 different proteins ranging from 319 kDa to 8 kDa. Protein profiles vary among species, and group into large (>200), intermediate(>100), and small (<100) protein classes as is found in chironomids. It is likely that silk evolved in a common ancestor of simuliids and chironomids

Les projets build, operate and transfer (BOT): une démarche contractuelle efficace dans les investissements internationaux

Dans le vaste champ du droit international des affaires, les projets «Build, Operate and Transfer» (BOT) signifiant «Construire, Exploiter et Transférer» et leurs variantes semblent moins connus du fait qu'ils représentent un type particulier d'investissement. La réalisation de ces projets fait intervenir de nombreux acteurs (notamment l'État hôte, la société concessionnaire et les cocontractants) aux intérêts souvent divergents mais qui tendent tous à la satisfaction d'un objectif commun: la réussite du projet. L'une des particularités de ces projets est que l'État ayant un fort taux d'endettement et d'impérieuses contraintes budgétaires limitant la capacité du secteur public aux besoins croissants en matière d'infrastructures, bénéficie sous certaines conditions, la participation du secteur privé qui supporte d'énormes risques financiers. Notre étude se veut d'abord une pénétration des mécanismes contractuels des projets BOT afin de déceler les enjeux qui font leur complexité. C'est à la suite de cette analyse que succèdera l'étude des problèmes juridiques affectant l'enveloppe financière, les garanties étatiques ainsi que l'allocation des risques. Dans la troisième partie, notre réflexion sera relancée pour comprendre des questions multiples liées à la sécurisation des investissements BOT réalisés dans les pays à instabilité politique particulièrement en Afrique. Le bilan s'ouvrira sur une analyse critique des sentences arbitrales ciblées en insistant sur des principes très généraux dont l'application a fait l'objet des débats animés en droit des investissements.

Healthy as a trout – as delicate as a dragon-fly

Travail créatif / Creative Work

Dynamic characterization of olfactory receptors in the fruit fly Drosophila melanogaster

Temporal changes in odor concentration are vitally important to many animals orienting and navigating in their environment. How are such temporal changes detected? Within the scope of the present work an accurate stimulation and analysis system was developed to examine the dynamics of physiological properties of Drosophila melanogaster olfactory receptor organs. Subsequently a new method for delivering odor stimuli was tested and used to present the first dynamic characterization of olfactory receptors at the level of single neurons. Initially, recordings of the whole antenna were conducted while stimulating with different odors. The odor delivery system allowed the dynamic characterization of the whole fly antenna, including its sensilla and receptor neurons. Based on the obtained electroantennogram data a new odor delivery method called digital sequence method was developed. In addition the degree of accuracy was enhanced, initially using electroantennograms, and later recordings of odorant receptor cells at the single sensilla level. This work shows for the first time that different odors evoked different responses within one neuron depending on the chemical structure of the odor. The present work offers new insights into the dynamic properties of olfactory transduction in Drosophila melanogaster and describes time dependent parameters underlying these properties.

Manual de pr??cticas de Bot??nica

Cuaderno de trabajo cuyo objetivo es convertirse en un instrumento que posibilite realizar pr??cticas de bot??nica. Est?? orientado a la investigaci??n did??ctica centr??ndose fundamentalmente en trabajos de clasificaci??n, observaci??n y comprobaci??n de leyes, experiencias motivantes para el profesor en su aproximaci??n al estudio de los vegetales. Cada una de las experiencias est?? estructurada en un planteamiento de objetivos, relaci??n de material a utilizar, esquema o dibujo de la experiencia, desarrollo de la misma en pasos claros y una serie de propuestas de post-actividades. La dificultad en la realizaci??n va en orden creciente, facilitando la operatividad de aprendizaje en los distintos niveles educativos desde el ??ltimo ciclo de Primaria hasta la Educaci??n Secundaria.

Cooperative Physics of Fly Swarms: An Emergent Behavior

We have simulated the behavior of several artificial flies, interacting visually with each other. Each fly is described by a simple tracking system (Poggio and Reichardt, 1973; Land and Collett, 1974) which summarizes behavioral experiments in which individual flies fixate a target. Our main finding is that the interaction of theses implemodules gives rise to a variety of relatively complex behaviors. In particular, we observe a swarm-like behavior of a group of many artificial flies for certain reasonable ranges of our tracking system parameters.

On-the-Fly Maintenance of Series-Parallel Relationships in Fork-Join Multithreaded Programs

A key capability of data-race detectors is to determine whether one thread executes logically in parallel with another or whether the threads must operate in series. This paper provides two algorithms, one serial and one parallel, to maintain series-parallel (SP) relationships "on the fly" for fork-join multithreaded programs. The serial SP-order algorithm runs in O(1) amortized time per operation. In contrast, the previously best algorithm requires a time per operation that is proportional to Tarjan’s functional inverse of Ackermann’s function. SP-order employs an order-maintenance data structure that allows us to implement a more efficient "English-Hebrew" labeling scheme than was used in earlier race detectors, which immediately yields an improved determinacy-race detector. In particular, any fork-join program running in T₁ time on a single processor can be checked on the fly for determinacy races in O(T₁) time. Corresponding improved bounds can also be obtained for more sophisticated data-race detectors, for example, those that use locks. By combining SP-order with Feng and Leiserson’s serial SP-bags algorithm, we obtain a parallel SP-maintenance algorithm, called SP-hybrid. Suppose that a fork-join program has n threads, T₁ work, and a critical-path length of T[subscript ∞]. When executed on P processors, we prove that SP-hybrid runs in O((T₁/P + PT[subscript ∞]) lg n) expected time. To understand this bound, consider that the original program obtains linear speed-up over a 1-processor execution when P = O(T₁/T[subscript ∞]). In contrast, SP-hybrid obtains linear speed-up when P = O(√T₁/T[subscript ∞]), but the work is increased by a factor of O(lg n).

Tsetse fly

These are magnified photographs of tsetse flies.

El nou jard?? bot??nic de Palma. 'El nuevo jard??n bot??nico de Palma'

Se denuncia la situaci??n de abandono y progresivo deterioro de la zona conocida como Es Carnatge, franja litoral situada en la bah??a de Palma. Se anuncia que a pesar de la degradaci??n ambiental ha sido reconocida como unidad de inter??s geol??gico y bot??nico. En los planes del Ministerio de Medio Ambiente figura la recuperaci??n de la zona, as?? como la creaci??n de un jard??n bot??nico. Se analizan las causas que han conducido a la situaci??n actual, enmarc??ndolas en una perspectiva global de la zona mediterr??nea y se apunta la necesidad de la conservaci??n del medio ambiente.

En Quim Botó i les traduccions al català el 1999. 'Quim Botó y las traducciones al catalán el 1999'.

Resumen en catalán

Grupo de bot??nica Aristolochia pistolochia

'Aristolochia pistolochia'.

Fly traps! : plants that bite back.

Historia sobre el mundo real donde se describe cómo un hombre investiga el mundo de las plantas carnívoras. Escrita desde un punto de vista muy personal, mezclando hechos con sentimientos, anima a los niños a pensar, sentir e imaginar lo que aprenden. El diseño de página tiene interesantes variaciones al diferenciar entre la historia y la información. El viaje del hombre se cuenta en caracteres grandes, mientras que los hechos sobre las plantas carnívoras están escritos con una letra más pequeña,lo que da una gran cantidad de información en una forma entretenida. Especialmente interesantes son las descripciones de cómo las plantas comen los insectos que capturan. Al final hay notas para el profesor.