Drosophilidae (Diptera) of Australia's Northern Territory: Ecology and biogeography

The drosophilid fauna is well documented in eastern Australia but is poorly known in other parts of the continent. This paper summarises what is known of this fauna in the Northern Territory (NT), and includes results from banana trapping in the humid and arid zones. The 42 recorded species include species that breed in fruit, fungi and/or flowers, and a larval predator of scale insects. Drosophilids occur in all three major climate zones (humid, semiarid and arid) but predominate in the humid zone. Banana-attracted species in the humid zone (wet-dry tropics) were common in all sampled habitats: urban, rainforest and open woodland. They included predominantly urban and/or rainforest species. Of the species collected in open woodland, some are likely to be breeding there, whereas others may have been intercepted during movement across the area. The semiarid fauna is a depauperate version of that found in the humid region. Only three species have been recorded in the arid region: an endemic arid specialist, and two cosmopolitan species (D. simulans and D. melanogaster ) in urban Alice Springs. Overall, the NT drosophilid fauna represents a depauperate version of that found in eastern Australia, probably because of climatic factors and natural barriers to range expansion. There is little evidence of regional endemism, with probably only one (and at most three) species endemic to the NT, and no evidence of independent, natural dispersion from nearby Indonesia.

Olfactory attractiveness of mixtures of some host plant and conspecific semiochemicals to the banana weevil Cosmopolites sordidus (Germar, 1824)

A simple "Y" shaped olfactometer was used in laboratory studies on the olfactory attractiveness of mixtures in various proportions of industrial analogues of some host plant and conspecific-based semiochemicals, or their combinations with banana rhizome, to the banana weevil. The aim was to identify factors that influence their attractiveness to the weevil, and consider the possibility for their use as lures for trapping the weevil in the field. Cosmopolites sordidus was attracted to the mixtures at specific concentrations and proportions of constituent chemicals. 6-methylhept-5-en-2-one was only attractive on its own at 1 µl/100 ml and in mixture with 4- mercaptophenol, but not at 10 µl, 0.01 µl, or in combination with banana rhizome. 4-mercaptohpenol and 2-n-butylfuran, which were compatible with most host plant-based chemicals and were attractive as a mixture, were perceived to be key elements in the composition of attractants to the weevil. It was concluded that in addition to the composition, other factors that may determine the attractiveness or otherwise of a mixture to C. sordidus are the proportions and concentrations of the constituent chemicals.

Storage At Low Temperature Differentially Affects The Colour And Carotenoid Composition Of Two Cultivars Of Banana.

Different storage conditions can induce changes in the colour and carotenoid profiles and levels in some fruits. The goal of this work was to evaluate the influence of low temperature storage on the colour and carotenoid synthesis in two banana cultivars: Prata and Nanicão. For this purpose, the carotenoids from the banana pulp were determined by HPLC-DAD-MS/MS, and the colour of the banana skin was determined by a colorimeter method. Ten carotenoids were identified, of which the major carotenoids were all-trans-lutein, all-trans-α-carotene and all-trans-β-carotene in both cultivars. The effect of the low temperatures was subjected to linear regression analysis. In cv. Prata, all-trans-α-carotene and all-trans-β-carotene were significantly affected by low temperature (p<0.01), with negative estimated values (β coefficients) indicating that during cold storage conditions, the concentrations of these carotenoids tended to decrease. In cv. Nanicão, no carotenoid was significantly affected by cold storage (p>0.05). The accumulation of carotenoids in this group may be because the metabolic pathways using these carotenoids were affected by storage at low temperatures. The colour of the fruits was not negatively affected by the low temperatures (p>0.05).

Avaliação de danos mecânicos causados em banana Nanicão durante as etapas de beneficiamento, transporte e embalagem

This study had as objective the evaluation of mechanical damages occurred in banana Nanicão during the improvement process, packing and distribution, identifying the probable critical points. The mechanical damages caused by transport, first cleaning; cleanness and sorting; preservation in the packing, transport, and mature were evaluated. The studied packing had been: torito wooden packing (18 kg), wood type ½ box, (13 kg) and cardboard (18 kg). The stage of preservation and transport of the fruits to the distribution center duplicated the light defects and quintupled the serious defects, causing rottenness after the acclimatization. The cardboard packing did not support the piling up and presented deformations, that resulted in the kneading the fruits of the inferior packing, causing a significant increase of the serious defects. The fruits conditioned in the involved packing of plastic bubble had presented an inferior number of serious damages when compared with the others packing, without the plastic.

Avaliação econômica da elaboração de banana-passa proveniente de cultivo orgânico e convencional

This work reports an economic evaluation of the dried banana production from an agroindustry located in Guaraqueçaba - PR State, Brazil. The conventional and the organic banana processings were evaluated by comparing the economic viability pointers. The dried organic banana is exported to the Europe and the dried conventional banana is commercialized in the region of Curitiba - PR. Both processings presented positive economic viability, however the dried organic banana presented better indices (TIR 94%, VPL R$ 486,009.39 and benefit cost relation of 2.11) than the conventional dried banana (TIR 14%, VPL R$ 34,668.00 and benefit cost relation of 1.17). The dried organic banana presented a cost of production of R$ 3.64, being 50.1% relative to the expense with insumos and 27% with labour. The dried conventional banana presented a cost of R$ 3.21, being 45.3% for insumos and 31.2% for labour.

EFEITO DA ASSOCIAÇÃO DE PECTINASE, INVERTASE E GLICOSE ISOMERASE NA QUALIDADE DO SUCO DE BANANA

The association of 0,03 % v/w pectinase (Clarex), 0,6 % v/w invertase (Invertase-S) and 0,5 % w/w glucose isomerase (Taka-sweet) in industrialized banana (Musa cavendishii) pulp, under conditions of hydrolysis 40oC, 15 minutes, was observed and compared to other three enzymatic treatements: 0,03 % v/w pectinase (Clarex); 0,03 % v/w pectinase (Clarex) associated to 0,6 % v/w invertase (Invertase-S); and 0,03 % v/w pectinase (Sigma) associated to 0,03 % cellulase (Sigma) to determine the quality using a group of physical, physico-chemical, chemical, microbiological and sensory properties of the banana juices obtained. These properties had not differ significantly in function of pectinases and celulase employed. The addition of invertase had increased sweetness and decreased viscosity in juice. On the other side, the addition of glucose isomerase in inverted juice was not able in increasing significantly fructose content.

Measurement of ethylene production during banana ripening

Introduction. This protocol aims at measuring fruit ethylene production during ripening. It can be used to compare ethylene production between different banana varieties or to compare ethylene production between fruit produced in different pedo-climatic conditions. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. This part describes the required laboratory materials and the three steps necessary for calculating the amount of ethylene produced during banana postharvest ripening. Possible troubleshooting is considered.

Extraction and purification of total RNA from banana tissues (small scale)

Introduction. This protocol aims at preparing total RNA for gene expression analysis by Northern blots, RT-PCR and real-time quantitative PCR; cDNA isolation by RTPCR; and cDNA library construction. The principle, key advantages, starting plant material, time required for obtaining total RNA and expected results are presented. Materials and methods. This part describes the required materials and the 27 steps necessary for preparing RNA from peel and pulp fruit tissue: preparation of plant tissue powder, preparation of the complete RNA extraction buffer and isolation of RNA from ground banana fruit tissue. Results. Extraction of total RNA by the method described makes it possible to achieve electrophoresis under denatured conditions and in vitro reverse transcription. An example for Northern blot analysis is illustrated.

Determination of banana fruit susceptibility to post-harvest diseases: wound anthracnose, quiescent anthracnose and crown rot

Introduction. This protocol aims at ( a) evaluating the resistance to post-harvest diseases within different genotypes of bananas, and ( b) comparing different origins of bananas ( geographic origin, physiological stage, etc.) for their susceptibility to post-harvest diseases. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. Materials required and details of the twelve steps of the protocol ( fruit sampling and inoculum preparation, wound anthracnose resistance study, quiescent anthracnose resistance study and crown-rot resistance study) are described. Results. Typical symptoms of the different diseases are obtained after artificial inoculation.

Biochemical characterization of pulp of banana fruit: measurement of soluble sugars, organic acids, free ACC and in vitro ACC oxidase

Introduction. We present some protocols aiming at partially characterizing banana fruit quality through measurement of some key biochemical parameters. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. This part describes the required laboratory materials and the steps necessary for achieving four protocols making it possible to measure sugar, organic acids and free ACC contents, and in vitro ACC oxidase activity. Results. Standard results obtained by using the protocols described are presented in the figures.

Measurement of banana green life

Introduction. This protocol aims at measuring the storage life potential of banana fruit, and at determining the physiological age of fruit. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. This part describes the required laboratory materials and the five steps necessary for calculating the banana green life duration, which corresponds to the number of days between the fruit harvest and climacteric crisis. Results. The measurement of O-2 and CO2 concentrations allows one to detect the climacteric peak which marks the end of the banana green life.

Mechanical characterisation of banana fruits

Introduction. This protocol aims at measuring the mechanical characteristics of bananas, especially peel and fruit hardness, and pulp firmness; it can also allow the mechanical characterisation of green or ripening fruit of different pedo-climatic origins and/or varieties. Materials and methods. This part describes the required laboratory materials and the three steps necessary for the measurement of the mechanical characteristics of bananas. Results. The data allow the drawing of a curve characterising the firmness of the fruit (slope), hardness of the peel (peak) and hardness of the pulp (plateau).

Methodology to forecast the harvest date of banana bunches

Introduction. This method is used to forecast the harvest date of banana bunches from as early as the plant shooting stage. It facilitates the harvest of bunches with the same physiological age. The principle, key advantages, time required and expected results are presented. Materials and methods. Details of the four steps of the method ( installation of the temperature sensor, tagging bunches at the flowering stage, temperature sum calculation and estimation of bunch harvest date) are described. Possible problems are discussed. Results. The application of the method allows drawing a curve of the temperature sum accumulated by the bunches which have to be harvested at exactly 900 degree-days physiological age.

Trapping of strangelets in the geomagnetic field

Strangelets arriving from the interstellar medium are an interesting target for experiments searching for evidence of this hypothetical state of hadronic matter. We entertain the possibility of a trapped strangelet population, quite analogous to ordinary nuclei and electron belts. For a population of strangelets to be trapped by the geomagnetic field, these incoming particles would have to fulfill certain conditions, namely, having magnetic rigidities above the geomagnetic cutoff and below a certain threshold for adiabatic motion to hold. We show in this work that, for fully ionized strangelets, there is a narrow window for stable trapping. An estimate of the stationary population is presented and the dominant loss mechanisms discussed. It is shown that the population would be substantially enhanced with respect to the interstellar medium flux (up to 2 orders of magnitude) due to quasistable trapping.