Biology subjects

Porretta, D.

Publications and source records attributed to Porretta, D..

5 recordsLinked to original sources

bioRxiv2025

Advancing Heterospecific Sterile Insect Technique Against Drosophila suzukii: selection of the optimal irradiation dose for D. melanogaster males

The spotted-wing drosophila (Drosophila suzukii), a highly invasive agricultural pest, poses significant challenges to fruit production worldwide. Traditional chemical control methods are costly and raise concerns about resistance and environmental sustainability. The Heterospecific Sterile Insect Technique (h-SIT) has emerged as a promising alternative, using sterile heterospecific males (Drosophila melanogaster) to suppress D. suzukii populations through reproductive interference. However, optimizing irradiation doses is critical to balancing male sterility, maintaining biological quality and mating performances. This study aimed to determine the optimal irradiation dose for D. melanogaster males by assessing their sterility, longevity, and courtship behavior following exposure to gamma-ray doses ranging from 80 to 180 Gy. Results showed a significant reduction in fertility across all irradiation doses, with near-complete sterility at 180 Gy. However, longevity decreased with increasing doses, with males irradiated at 160-180 Gy showing a lifespan reduction of up to 50 days compared to controls. Behavioral trials revealed that irradiated D. melanogaster males retained their courtship ability toward D. suzukii females, although males exposed to 160 Gy exhibited reduced courtship activity. These findings highlight that, among the tested doses, 80 Gy emerged as the most effective, preserving male longevity and mating performance while significantly reducing fertility. While 180 Gy achieved the highest sterility, the potential lifespan and courtship behavior trade-offs warrant further evaluation. Future studies should evaluate field performance to refine the balance between sterility, longevity, and mating performances for effective D. suzukii population suppression.

ecology↗

bioRxiv2024

Can reproductive interference be integrated into the Sterile Insect Technique for pest control? Insights from the spotted wing fly Drosophila suzukii

BACKGROUNDReproductive interference (i.e., sexual interaction between males of one species and females of another species that reduce the fitness of one or both the interacting individuals) is an important species interaction significantly affecting population dynamics and persistence. However, its exploitation in pest control remains overlooked. Here, we investigated the possible integration of reproductive interference into the Sterile Insect Technique (SIT) to develop a heterospecific SIT (h-SIT). Under this approach, contrary to the classic SIT, sterile heterospecific males from closely related, non-pest species are released to compete with the pest population for mates. At this aim, we focused on the invasive pest species Drosophila suzukii and used D. melanogaster as the control species. First, we investigated the effect of irradiation on D. melanogaster sterility and longevity. Then, we tested the mating performance of irradiated males and their ability to reduce the D. suzukii fitness. RESULTSWe found by microcosm experiments that: i) irradiation induced high levels of D. melanogaster male sterility without reducing longevity; ii) irradiated D. melanogaster males court D. suzukii females as much as D. suzukii males and they couple, mate and fecund heterospecific females; iii) irradiated D. melanogaster males significantly reduce the offspring of D. suzukii females under two different species ratios. CONCLUSIONSOur results provide the first foundation to develop a heterospecific Sterile Insect Technique against D. suzukii and fuel to test this approach against other groups of pest species.

ecology↗

bioRxiv2024

Adaptation to water salinity changes: phenotypic plasticity meets and moulds carry-over effects in sea rock-pool mosquitoes

Environmental conditions experienced during early-life can shape trait expression after metamorphosis. Direct carry-over effects occur when the value of a trait expressed at an early stage directly determines its expression at later stages, maintaining phenotypic continuity across metamorphosis. However, environmental factors generally affect multiple traits whose interaction might shape developmental trajectories. Here, we tested the hypothesis that trait interactions can shape direct carry-over effects by examining the interplay between behavioural and morphological plasticity in the sea rock-pool mosquito Aedes mariae under varying salinity conditions. We found plastic changes in body size and behaviour. Higher salinity reduced larval body size and increased resting behaviour at the water surface while browsing activity decreased. Under constant conditions, larval body size was positively correlated with pupal size, indicating a direct carry-over effect. However, this relationship was disrupted as salinity increased due to larval size-dependent behavioural plasticity which decouples pupal morphology from larval size. Our results show that environmental conditions modulate trait integration and modify direct carry-over effects. These findings highlight the importance of considering multiple traits when studying developmental plasticity and contribute to the ongoing debate on the extent to which one life stage is coupled to the others across metamorphic boundary.

ecology↗

bioRxiv2024

Behavioural variation in background colour matching and the effect of social environment in rock-pool mosquitoes

Several animal species conceal themselves from potential predators by actively choosing environmental patches that best match body colouration and chromatic patterns. Growing evidence shows that a variety of contexts and conditions can affect this background choice behaviour, yet the extent of this variety remains largely underexplored. Here, we explore the effect of disturbance and social environment on background colour choice behaviour in the rock-pool mosquito Aedes mariae. We exposed single individuals and groups of individuals to experimental arenas made of dark and bright patches, and recorded individuals colour preferences when alone and within groups, as well as before and after a disruptive event. We found a marked prevalence of individuals favouring a dark background and an among-individual variation in choice over replicated trials. Moreover, we observed a non-significant effect of disturbance but a significant role of the social environment. In fact, being caged in groups significantly increased the proportion of mosquitoes choosing the dark background. Our results provide strong evidence of a background colour choice in Ae. mariae, a density-dependence of this choice, and a non-negligible inter-individual variation in this behaviour. Overall, these findings offer intriguing insights into the background choice behavioural variation and flexibility in mosquitoes.

ecology↗

bioRxiv2018

Hybridization and rampant mitochondrial introgression among fire salamanders in peninsular Italy

Discordance between mitochondrial and nuclear patterns of population genetic structure is providing key insights into the eco-evolutionary dynamics between and within species, and their assessment is highly relevant to biodiversity monitoring practices based on DNA barcoding approaches. Here, we investigate the population genetic structure of the fire salamander Salamandra salamandra in peninsular Italy. Both mitochondrial and nuclear markers clearly identified two main population groups. However, nuclear and mitochondrial zones of geographic transition between groups were located 600 km from one another. The overall pattern of genetic variation, together with morphological and fossil data, suggest that a rampant mitochondrial introgression triggered the observed mitonuclear discordance, following a post-glacial secondary contact between lineages. Moreover, at a shallower level of population structure, we observed evidence of asymmetric introgression of nuclear genes between two sub-groups in southern Italy. Our results clearly show the major role played by reticulate evolution in shaping the structure of Salamandra salamandra populations and, together with similar findings in other regions of the species range, contribute to identify the fire salamander as a particularly intriguing case to investigate the complexity of mechanisms triggering patterns of mitonuclear discordance in animals.

evolutionary biology↗