Drinking water samples were collected from boreholes in six locations in Ughelli and environs in Delta State of Nigeria and were treated by filtration through a substrate colonized with mycelium of Pleurotus tuber-regium. Water samples were analysed for pH, heavy metal concentration and microbiological content before and after filtration. Results obtained showed that the pH of unfiltered water samples were acidic (5.0 – 5.8) and below the WHO and SON permissible limits for drinking water. The same trend was followed by the concentrations of heavy metals such as lead, iron, zinc and chromium. Water samples from all six locations also had high total bacterial and coliform counts. Filtration through the mycelium colonized substrate showed adjustment of pH to a range within the WHO permissible limits. Reduction in heavy metal concentration ranged from 45.0 – 100%. Total bacterial count of mycofiltered water samples was impressively reduced by 77.3 – 100% and coliform count was not detected. The results obtained in this study makes mycofiltration a potential cost-effective and efficient technique for the treatment of potable water for domestic use.
Behaviour-modifying chemicals like pheromones and kairomones hold a great potential in pest management. Evidences from mating behaviour studies of the banana weevil, and from the weevil's responses to their freeze-killed conspecifics, body washes/extracts, live conspecifics (olfactometer studies), and trapped volatiles of mature and immature adults clearly suggest that two types of pheromones are produced in this insect: a female produced sex pheromone and a male produced aggregation pheromone. Both are perceived by olfactory means. The latter has already been isolated by earlier workers and is in use in control programs. Greater successes may however, be recorded with the control of this pest (e.g. in mating disruptions, mass trappings, pest monitoring) if the female-sex pheromone also gets finally isolated, and used in conjunction with good cultural practices.
The banana weevil, Cosmopolites sordidus Germar mates repeatedly in its lifetime. No elaborate courtship behavior was seen before mating in the laboratory. However, 'sniffing' (an activity by which male weevils used their antennae to contact the abdominal tip of the female, as if to perceive some stimulus), often preceded mating. This observation may be an indication of a chemical pheromone involved in the mating behaviour of this insect. Male banana weevils generally displayed aggressive mating behaviour. Matings occurred under both light and dark conditions, but significantly more in the dark. A direct and positive linear correlation was observed between mating and sniffing under both light and dark conditions. Similar trends or correlations were observed between mating and mating duration; mating and sniffing durations respectively.
This study was to determine the age at sexual maturity and the relationships between age and internal reproductive organs of Cosmopolites sordidus. Male banana weevils become sexually mature 18 days after emergence (DAE), that is after 2 weeks of adult eclosion, in spite of the fact that spermatogenesis is completed at emergence. A positive correlation exists between age and male internal organs, for example for mean testis diameter (r = .849, p ≤ .001), mean seminal vesicle diameter (r = .679, p ≤ .001), mean accessory gland length (r = .561, p ≤ .01) and mean accessory gland diameter (r = .498, p ≤ .05), respectively. Significant differences were recorded between sexually mature and immature weevils with respect to mean testis diameter (T = 4.471, p ≤ .001) and mean seminal vesicle diameter (T = 3.939, p ≤ .001), but not with mean accessory gland length and mean accessory gland diameter (T = 1.899 and 1.661). Male internal organs were visibly underdeveloped at emergence but became significantly enlarged and developed on attainment of sexual maturity. Female C. sordidus, on the other hand, are sexually mature at 5 DAE. There was also a strong, positive correlation between age of females and mean ovariole length (r = .656, p ≤ .001), and significant differences existed between mean ovariole lengths of sexually mature and immature females (T = 4.306, p ≤ .001). Increasing age of females witnessed progressive increases in ovariole lengths and developmental changes within female ovarioles and calyces. The findings made here may be helpful in Musa germplasm screening works, as weevils bred on susceptible cultivars may reveal similar results, while those bred on resistant ones may experience possible delays in their reproductive developments.
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