42 research outputs found
A second record of Aedes (Stegomyia) albopictus (Diptera : Culicidae) in Malta
The presence of Aedes albopictus (Skuse, 1894) was recently confirmed in Malta (Gatt et al., 2009).
Three more adult female mosquitoes were caught indoors by the author from another locality
(Marsascala) located in east Malta, and identified from morphological features. This is the second time
this species has been recorded for the Maltese archipelago and represents an addition to the nine
previously recorded Culicidae mosquito species from the Maltese Islands. Since the species is a known
vector for several serious diseases including dengue fever, its occurrence in the Maltese islands needs to
be noted by the Health Authorities and measures to contain its spread and/or prevent its establishment,
undertaken.peer-reviewe
A vulnerability index for successful eradication of IAPs targets interventions at their most vulnerable stages
Invasive alien plant species (IAPs) are non-native plant species whose introduction and spread
outside their natural range poses a threat to biodiversity. Their removal is often financially and
environmentally costly from repeated interventions. Tackling IAPs at their most vulnerable
stages can be a cost-reducing and effective strategy. A vulnerability index has been devised to
plan an IAPs removal strategy based on attacking the most vulnerable stages of a species and
focuses on the ease and effectiveness of removing aerial and root biomass as well as propagules.
The need for repeated interventions is also factored in the vulnerability index since this forms
part of the weakening strategy.peer-reviewe
A multitrophic culture system for the production of black soldier fly larvae (Hermetia illucens)
Goals number 2, 11 and 12 of the 17 sustainable development goals, enacted by the United Nations as part of the 2030
Agenda for sustainable development, aim to end hunger as a priority, create sustainable cities and above all encourage
responsible consumption and production. With increasing world population and higher demand for food, we need
to find ways of producing cheap sources of protein and lipid that may in turn be used as animal or aquaculture feed.
A multitrophic system involving mealworm larvae (MWL, Tenebrio molitor) and black soldier fly larvae (BSFL, Hermetia
illucens) was developed to transform fruit and vegetable kitchen waste into usable biomass. MWL, fed mainly on kitchen
waste, reached an average prepupal length of 2.4 cm, fresh weight of 0.12 g and dry matter protein and lipid contents of
44.2% and 16.5% respectively, with an average specific growth rate (SGR) of 2.2%/day and a feed conversion ratio (FCR)
of 7.9. Conversely, BSFL fed on a variety of feeds, including MWL frass, kitchen waste and oats, had an average prepupal
length of 1.3 cm, fresh weight of 0.16 g and dry matter protein and lipid contents of 41.4% and 26.3% respectively, with
an average SGR and FCR of 4.3%/day and 8.9 respectively. The BSFL fed MWL frass obtained some of highest SGR and
lowest FCR values, with one group achieving 7.5%/day and 2.9 respectively. This investigation has demonstrated the
feasibility of a multi-trophic production system using kitchen waste to feed MWL whose frass was in turn used to feed
BSFL thereby producing protein- and lipid-rich biomass that can serve as animal or aquaculture feed.peer-reviewe
Seed germination reports for five coastal and inland species from the Maltese Islands
This study investigated seed germination in five indigenous species of plants in the Maltese Islands, predominantly occurring in coastal garrigue habitats but also inland, namely Drimia maritima, Periploca angustifolia, Asparagus aphyllus, Myrtus communis, and Pancratium maritimum. Different germination protocols were tested for one or more populations, namely: four different temperature regimes - constant 15, 20 and 25°C as well as alternating 23.5/15°C; three different photoperiods, 12/12, 16/8 and 0/24 light/dark. The best germination results for each species are provided and additional notes on the species and germination behaviour are also given.peer-reviewe
Use of morphocolorimetric analysis to monitor germination success of hydroprimed seeds of Coronilla valentina subsp. glauca (Fabaceae)
This research aimed to investigate if the germination rate of Coronilla valentina seeds
(Fabaceae) increased when subjected to extended hydro-priming. Analysis of hydroprimed
seeds was carried out by using morphocolorimetric analysis to characterise the imbibition at
different hydration time intervals. Seeds that had not been hydro-primed represented the
untreated control. Seed swelling is a reliable and time-efficient method to measure seed imbibition,
yet a poor predictor of seed germination success. Timing and temperature of the
hydropriming treatment influence the germination rate of C. valentina subsp. glauca, with the
optimum hydropriming treatment, was found to occur within a 72h period following the 75°C
to 25°C treatment.peer-reviewe
Use of Suillus collinitus to increase survival rate and resilience of transplanted Pinus halepensis seedlings in habitat restoration practices
In-situ conservation is considered the best way to preserve biodiversity where multiple species
can persist with all their natural ecological interactions. The latter element is often ignored.
Criticalities can arise when ex-situ grown plants are translocated in-situ without their natural
soil microbial associations, especially where abiotic stresses can be severe. Mycorrhizal Fungi
(MF) provide several benefits to plants and ecosystem in which are present. The aim of the project
was to investigate the use of indigenous MF to enhance acclimatization and survival of exsitu
grown plants translocated for habitat restoration. The seeds of Pinus halepensis Mill. as
well as sporocarps of naturally associated indigenous MF Suillus collinitus (Fr.) Kuntze (1898),
were collected from Natura 2000 sites in the Maltese Islands. P. halepensis seeds were germinated
under greenhouse conditions. S. collinitus was inoculated at sowing and seedling stage by
placing fragments of the ripe sporocarps in the P. halepensis seedling trays. All the mycorrhized
plantlets produced have been reintroduced into selected area of Natura 2000 in the Maltese
Islands as part of SiMaSeed restoration project. Such MF inoculation actions can help to
enhance restoration and resilience of habitats to reduce biodiversity loss.peer-reviewe
Axenic culture and DNA barcode identification of wood decay fungi from the Maltese Islands
Wood-decaying fungi are important study subjects for their ecological role as well as for
their biotechnological applications. They break down lignin, cellulose, and hemicelluloses using
enzymes that modify the chemical structure of these complex macromolecules. Due to their ability to
degrade wood, these fungi can create structural damage to wooden structures and to trees, especially
those with very low level of fitness. Previous studies on wood decay fungi in the Maltese Islands
are limited to records and checklists described by a handful of authors. The aim of this study was
to provide a comprehensive description of wood decay fungal diversity in the Maltese Islands
including an updated checklist based on DNA barcoding, as well as to establish the first wood-decay
fungal culture collection at the Biology Department Seed Bank of the University of Malta. Several
surveys were carried out during the rainy season along wooded areas of the Maltese Islands as well
as in historical gardens. Isolates were identified using macro- and micro-morphological features,
dichotomous keys, as well as molecular data. Basidiomes were recorded growing on 14 different
host plant species, 11 axenic cultures have been made and 9 species of wood decay fungi have been
conclusively identified by DNA barcoding. The collection of the axenic isolates includes one of
Aurificaria cf. euphoria, three of Ganoderma resinaceum sl., two of Laetiporus sulphureus, one of Inonotus
sp., one of Inonotus rickii anamorph, one of Inocutis tamaricis, one of Stereum hirsutum, and one of
Pleurotus eryngii. However, the mycelium of Coriolopsis gallica, though collected and identified, could
not be isolated.peer-reviewe
The effect of alloying elements on the properties of pressed and non-pressed biodegradable Fe–Mn–Ag powder metallurgy alloys
Current trends in the biodegradable scaffold industry call for powder metallurgy methods in which compression cannot be applied due to the nature of the scaffold template itself and the need to retain the shape of an underlying template throughout the fabrication process. Iron alloys have been shown to be good candidates for biomedical applications where load support is required. Fe–Mn alloys were researched extensively for this purpose. Current research shows that all metallurgical characterisation and corrosion test on Fe–Mn and Fe–Mn–Ag non pre-alloyed powder alloys are performed on alloys which are initially pressed into greens and subsequently sintered. In order to combine the cutting-edge field of biodegradable metallic alloys with scaffold production, metallurgical characterisation of pressed and non-pressed Fe, Fe–Mn and Fe–Mn–Ag sintered elemental powder compacts was carried out in this study. This was performed along with determination of the corrosion rate of the same alloys in in vitro mimicking solutions. These solutions were synthesised to mimic the osteo environment in which the final scaffolds are to be used. Both pressed and non-pressed alloys formed an austenite phase under the right sintering conditions. The corrosion rate of the non-pressed alloy was greater than that of its pressed counterpart. In a potentiodynamic testing scenario, addition of silver to the alloy formed a separate silver phase which galvanically increased the corrosion rate of the pressed alloy. This result wasn't replicated in the non-pressed alloys in which the corrosion rate was seen to remain similar to the non-silver-bearing alloy counterparts.peer-reviewe
Use of waste polystyrene as feed for mealworms (Tenebrio molitor)
This study aimed to determine what percentage of the feed provided to the mealworm larvae of Tenebrio molitor (MWL) could be substituted by polystyrene (PS) whilst retaining mealworm viability. The survival and growth rates, as well as the general performance of the larvae, were followed for a 6-week duration. Four test groups in three independent replicates of MWL, each with 300 larvae at the 8th instar, were fed on varying PS-bran percentages for six weeks under standard growth environment conditions. The four feeding regimes were 0, 50, 75 and 100% PS. The remainder of the feed for the 0, 50 and 75% groups was wheat bran. A 5g carrot supplement was provided for all groups weekly. The mealworms were monitored for mortality, percentage weight gain (%WG) and percentage length gain (%LG), and changes in their lipid and protein content at the end of the 6-week trial. Feeding solely PS did not provide the best degradation of PS, with only 27.39% degradation in six weeks. The 75% PS treatment had the lowest %PS consumption at 21.74%. The best alternative was to provide a feed consisting of 50-50 PS-wheat bran supplemented with carrots giving the highest %PS consumption at 31.06%. Furthermore, over six weeks, the 50% PS treatment larvae had the best %LG and %WG at 47.1% and 278.6%, respectively. By comparison, the 100% PS treatment achieved a %LG and %WG of 36.6% and 205.4 respectively. Mortalities of the 50% PS treatment were of 54.7%, similar to the 75% PS group, whilst, for the 100% PS, mortalities were 73.89%. The control group achieved the lowest mortalities at 22.78%. An additional test was conducted to investigate if a diet consisting of 50% PS significantly affected the protein and lipid content of the MWL compared to the control group. Analysis showed a statistically significant difference in protein content, with the 50% PS diet resulting in a higher protein content of 56.49% and 25.51 % lipid content, on a dry matter basis, when compared to the control group. In conclusion, the 50% PS treatment larvae gave the best larval growth and survival rates out of the three treatments with PS provided in their diet, whilst the 100% PS gave poor results as PS degradation was not as efficient in this test group. A better approach to making use of waste PS is actually to provide the PS as part of a diet supplemented with natural feeds, such as wheat bran and carrots. For the commercialising of this concept, further studies need to be conducted.peer-reviewe
Trichoderma in the Maltese Islands
This study assessed presence of Trichoderma spp. in the Maltese Islands. Isolates were identified using dichotomous keys and DNA barcoding. Ten distinct isolates were obtained from different soils and other substrates, and were identified as T. virens, T. citrinoviride, T. gamsii, and, in the former T. harzianum species complex, T. breve, T. afroharzianum and T. atrobrunneum. Five out of these six fungi are reported for the first time in the Maltese Islands, and T. brevis is reported for the first time in Europe.peer-reviewe