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Recapping and mite non-reproduction in the endemic honey bee subspecies of Malta : Apis mellifera ruttneri

2026-03-12T13:01:36Z

Title: Recapping and mite non-reproduction in the endemic honey bee subspecies of Malta : Apis mellifera ruttneri Abstract: Scientific literature concerning Apis mellifera ruttneri, the endemic honey bee of the Maltese Islands is still limited. Recently, its behaviour and development gained an increasing attention particularly in relation to Varroa resistant traits. Nevertheless, the effect of recapping on mite reproduction remains controversial. In October 2021, a standardized study was set up for the evaluation of two resistant traits: recapping and mite non-reproduction (MNR). In total 40 colonies (A.m.ruttneri n = 20, and Buckfast n = 20, sister queens) of approximately the same size, were distributed across two apiaries, one in Wardija and the other in . Hygienic behaviour evaluated by the pin-test method was higher in the Buckfast than in A.m.ruttneri, but this was not significant. In contrast, A.m.ruttneri produced significantly more honey than the Buckfast group. MNR is very restricted for analysis due its strict requirements in the right number of mites in relation to the brood. A Varroa treatment in December 2021 was applied to reduce mite loads, subsequently the first MNR/recapping assessment occurred in June 2022 and continued until April 2023. The measurements were repeated three times across a ten-month period, but samples could not be further collected due to insufficient mite infestation and colony losses emerging from to constant strain of the mites. High recapping rates and low mite reproductive success were consistent in A.m.ruttneri. In the Buckfast group, both at the colony level and at the cell level elevated rates of recapping were linked with MNR. However, this direct outcome of recapping on mite reproduction was not observed in A.m.ruttneri. Even though, both traits seem to mainly be driven by seasonality and apiary environment, this effect was stronger in A.m.ruttneri. Brood infestation related to an increased non-targeted recapping in A.m.ruttneri but not in the Buckfast. Despite brood infestation was relatively high, most colonies preceded by A.m.ruttneri still survived until the end of the study, and afterwards. All this implies that A.m.ruttneri shows a certain degree of tolerance and resistance expressed both through MNR and an extensive mite infestation tolerance. This is likely due to a combination of recapping and possibly other traits such as VSH, physiological adaptations along with the rhythm of brood dynamics amalgamated to the seasonal changes of to the Maltese Islands. Description: M.Sc.(Melit.)

The ampelographic and physicochemical characteristics of Muskatell and Marsusa Sewda grapevine varieties

2026-02-20T10:08:31Z

Title: The ampelographic and physicochemical characteristics of Muskatell and Marsusa Sewda grapevine varieties Abstract: This study investigated the ampelographic and physicochemical characteristics of three Vitis vinifera L. varieties cultivated at the National Viticulture and Oenology Centre in Buskett, Malta: Muskatell, Marsusa Sewda 1, and Marsusa Sewda 2. A total number of twenty-four grapevine samples were analysed over two consecutive growing seasons (2024–2025). Morphological characterisation followed International Organisation of Vine and Wine (OIV) descriptors, with weekly observations recorded from pruning to harvest. Cumulative Growing Degree Days (GDD) were calculated to assess phenological development, with Muskatell, Marsusa Sewda 1, and Marsusa Sewda 2 reaching maturity at approximately 1,799, 1,910, and 1,929 °C.day, respectively. Muskatell produced compact clusters (OIV 204: 9) and globose green-yellow berries (OIV 223: 2) reaching 22.3 °Brix at harvest. Marsusa Sewda 1 bore dense blue-black clusters (OIV 204: 9) with broad-ellipsoid berries achieving 21.2 °Brix, while Marsusa Sewda 2 exhibited looser clusters (OIV 204: 3) and heavier seeds (OIV 242: 7), indicating improved aeration and fertility. Spectrophotometric and MP-AES analyses revealed total polyphenol contents ranging between 60–120 µg GAE/ml and dominant mineral elements of potassium, calcium, and magnesium across varieties, with minor iron and sodium concentrations. Statistical analyses (ANOVA, p < 0.05; PCA) confirmed significant varietal differentiation in cluster compactness, berry morphology, sugar, and polyphenolic accumulation. The integration of OIV descriptors, GDD progression, and biochemical data provides a robust framework for identifying, conserving, and valorising indigenous Maltese grapevine germplasm within Mediterranean viticulture. Description: M.Sc.(Melit.)

Investigating socially responsible fresh produce consumption : a Maltese case study

2026-02-20T10:03:42Z

Title: Investigating socially responsible fresh produce consumption : a Maltese case study Abstract: Social responsibility is the moral duty of individuals and organisations to act in ways that benefit society rather than solely seeking profit. This ideology is reflected in the ESG framework through the ‘Social’ component, which evaluates how companies interact with employees, communities, and society, including labour rights, workplace safety and fair wages. This study investigates how social responsibility influences consumer behaviour in Malta’s fresh produce market, with the aim of identifying the gap between ethical intentions and actual purchasing decisions. There are few studies on the social responsibility of fresh produce consumption, especially in regions that rely on imports and face geographic constraints. To address this lacuna, a mixed-methods approach was used, linking quantitative data from an extensive consumer survey with qualitative perceptions from semi-structured interviews with expert stakeholders. The research uncovers a significant gap caused by consumers’ limited understanding of social responsibility, often mistaken for the heuristic of ‘buying local’. The findings suggest that the intention-behaviour gap does not stem from weak ethical beliefs but from structural limitations, such as price sensitivity, convenience-driven habits, and limited information. Despite consumers expressing strong social values, the current food systems restrict their ability to recognise, access, and afford socially responsible choices. Bridging this gap will require institutional reforms that shift responsibility from individual consumers to a market system where ethical options are the most affordable, accessible, and transparent. Description: M.Sc.(Melit.)

Electrical conductivity modelling in calcareous soils of the Maltese Islands : developing a soil:water suspension to saturated paste conversion model

2026-02-05T07:19:03Z

Title: Electrical conductivity modelling in calcareous soils of the Maltese Islands : developing a soil:water suspension to saturated paste conversion model Abstract: Soil salinity is a critical factor influencing soil health and agricultural productivity, typically measured through the electrical conductivity (EC) of a saturated soil paste extract (ECe). However, this standard method is time-consuming, and alternative soil: water suspension methods (EC(soil : water)) offer quicker results, though conversion models are often soil-specific. This study aimed to develop models to convert EC (1:1, 1:2, and 1:5) to ECe for Malta's calcareous soils, while also assessing the impact soil texture, carbonate, and organic matter content have on model accuracy. Moreover, the effect these variables have on soil salinity in the field was also investigated. A total of 134 soil samples with varying textures, carbonate, and organic matter levels were analysed. The results indicate a considerable variability in salinity levels among the sampled soils with a mean average of 3772 µS/cm. Out of the different soils analysed, 104 can be classified as non-saline, with an electrical conductivity (e) less than 4,000 µS/cm. This study produced generalized models (ECe = 10(a(logEC(soil))+b)) with strong correlation coefficients (r² = 0.91-0.93, p < .001). Models specific to fine- and medium-textured soils, soils with 35-50 % carbonate content, and those with 2.5-4.2 % organic matter demonstrated even higher accuracy (mean r² = 0.96). Validation using 22 independent samples confirmed the reliability of these models (RMSE = 0.93-0.97 dS m⁻¹; NSE = 0.95-0.97), except for coarse-textured soils. These findings suggest that general models can be reliably applied to most of Malta’s soils, with exceptions for high sand content soils. This methodology was also applied to analyse metal concentrations, and the resulting general model can estimate the concentrations of key metal ions Na⁺, Ca²⁺, Mg²⁺, and K⁺ in the soil saturation extract (ECe) using measurements derived from soil:water suspensions at 1:1, 1:2, and 1:5 ratios. No significant correlation between ECe and the levels of sand, silt, and clay was observed, nor were significant differences in EC found across contrasting textural classes (p = .465). Weak positive correlations were detected between EC and both carbonate (rs = 0.216, p < .05) and OM content (rs = 0.269, p < .05). These results suggest that salinity in these soils is not primarily governed by physical properties like texture. Organic matter levels, when plotted against sand and clay content, showed no significant correlation, indicating that other factors such as soil management practices and environmental factors seem to have a more pronounced impact on soil salinity. Description: M.Sc.(Melit.)