OAR@UM Community:

Assessing the conservation status of selected insects in the Maltese Islands

2026-07-15T07:28:16Z

Title: Assessing the conservation status of selected insects in the Maltese Islands Abstract: The main aim of this dissertation is to present an evaluation of the conservation status of selected groups of insects of the Maltese fauna, including a reassessment of selected species listed in Schembri and Sultana (1989). Species were evaluated using IUCN criteria based on data from literature published over the last 30 years. Selected species within 48 selected families from Coleoptera, Diptera, and Lepidoptera were considered on the basis of the information available. The conservation status using IUCN categories as well as notes are provided for each species that was (re)evaluated. Overall, a total of 381 species were successfully (re)assessed, including 95 species from Schembri and Sultana (1989). The overall percentages of IUCN categories that were evaluated is as follows: ‘Least Concern’ – 6.3%, ‘Near Threatened’ – 5.5 %, ‘Vulnerable’ – 13.6%, ‘Endangered’ – 27.3%, ‘Critically Endangered’ – 15.5%, ‘Possibly Extinct’ – 13.6%, ‘Data Deficient’ – 17.6%, and ‘Not Applicable’ 0.3%. There was a significant change in the IUCN conservation status of selected species that were mentioned in Schembri and Sultana (1989), with 59% of species evaluated being in a threatened or near threatened category, an increase from 1% to 11% of species classified as ‘Possibly Extinct’, and from 0% to 3% in the ‘Least Concern’ and ‘Near Threatened’ categories; and a decrease in the ‘Vulnerable’ (from 21% to 18%) and the ‘Endangered’ (from 30% to 24%) categories. This may be due to using a more objective approach when evaluating the species with the standardised IUCN criteria, rather than the previous subjective approach. When comparing distribution type (endemic vs nonendemic), no significant difference was found on extinction risk. This was probably due to the fact that even non-endemic species are frequently threatened at the local scale because of their small extent of occurrence and area of occupancy at the national scale, in turn largely a consequence of the small size of the islands. Moreover, the last recorded locations of ‘Critically Endangered’ and ‘Possibly Extinct’ species, as well as all the distribution data for threatened species, were visualised on QGIS maps, which display clustering in locations such as Buskett, Marsa, Salina, Mġarr, Rabat, Dingli, Marsaskala, Marsaxlokk, Girgenti, Mellieħa, Għar Lapsi in Malta, and Ramla, Marsalforn, Victoria and Xlendi in Gozo. These locations include habitats such as sand dunes, salt marshes, and freshwater pools, and are considered vulnerable due to human impact, climate change, and habitat loss. Therefore, these locations should be of conservation priority. In conclusion, long-term monitoring as well as further research into the ecology of the species evaluated, as well as assessment of both direct and indirect impacts that are contributing to insect population decline, is recommended in order to develop better conservation strategies for the preservation of the Maltese insect fauna. Description: M.Sc.(Melit.)

Evaluating the influence of temperature fluctuations on soil state in the Maltese Islands using remote sensing techniques

2026-07-15T07:24:39Z

Title: Evaluating the influence of temperature fluctuations on soil state in the Maltese Islands using remote sensing techniques Abstract: Increasing temperatures and droughts present growing environmental challenges in the Mediterranean region, particularly for small island environments like the Maltese Islands where water resources are limited and climate pressures are intensifying. This study examined the spatial and temporal variability of soil surface temperature and soil dryness across the Maltese Islands over a ten-year period (2015–2024) using remote sensing techniques. The analysis focused on seasonal and interannual changes in Land Surface Temperature (LST) and the Temperature Vegetation Shortwave Dryness Index (TVSDI), and on evaluating the relationship between surface temperature and soil dryness under semi-arid conditions. Wet and dry seasons were analysed separately to capture the strong seasonal contrasts characteristic of the Mediterranean climate. Statistical analyses, including correlation and regression tests were applied to assess relationships between LST and TVSDI across districts and seasons. The results revealed a clear seasonal contrast, with dry-season LST values consistently exceeding wet-season values across all districts. While district-level differences in LST were not statistically significant once seasonality was considered, spatial patterns showed persistently higher temperatures in urbanised districts and cooler conditions in rural districts and hydrologically active areas. TVSDI values remained relatively uniform during the wet season, reflecting the homogenising effect of winter rainfall, but exhibited pronounced spatial and temporal variability during the dry season. The South Eastern, Western and Gozo districts consistently recorded the highest dryness levels, with extreme conditions observed in 2016, 2020 and particularly 2024. A strong and statistically significant positive relationship between LST and TVSDI was identified during the dry season, indicating that surface temperature is the dominant driver of soil dryness under moisture-limited conditions. In contrast, weak wet-season relationships highlighted the moderating role of rainfall. Overall, the findings demonstrated the effectiveness of LST-based remote sensing indices for monitoring soil dryness in semi-arid island environments and provided insight into emerging drought trends under ongoing climate change. Description: M.Sc.(Melit.)

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.)