Biology subjects

Metelmann, S.

Publications and source records attributed to Metelmann, S..

4 recordsLinked to original sources

bioRxiv2026

Thermal fertility limits reveal underestimated climatic suitability for Aedes aegypti in temperate regions

Predicting species distributions under climate change typically relies on thermal limits for survival. However, recent evidence suggests that sublethal temperatures that reduce fertility can constrain distributions more strongly than temperatures causing mortality alone. Despite the importance of mosquitoes as vectors of human disease, thermal fertility limits remain largely uncharacterized in these insects. Here, we show that fertility in Aedes aegypti is highly sensitive to thermal stress and exhibits distinct sex-specific responses. Adult males were more vulnerable to both heat and cold exposure than females. At 38{degrees}C, survival remained high in both sexes despite significant reproductive impairment, indicating that sterility can occur independently of mortality. Similarly, exposure to 2{degrees}C induced male sterility whereas females maintained reproductive function. Morphological analyses of reproductive organs showed temperature-associated damage consistent with the observed fertility loss. Incorporating these fertility thresholds into ecological niche models generated different predictions of climatic suitability compared with models based solely on lethal temperature limits. Our findings demonstrate that sublethal effects on reproduction can substantially influence estimates of mosquito climatic suitability and highlight the importance of incorporating fertility based thermal limits into projections of vector distributions and disease risk under future climate change.

ecology↗

bioRxiv2024

UK mosquitoes are competent to transmit Usutu virus at native temperatures

Usutu virus (USUV) is an emerging zoonotic virus transmitted primarily by Culex mosquitoes. Since its introduction into Europe from Africa during the late 20th century, it has caused mortality within populations of passerine birds and captive owls, and can on occasion lead to disease in humans. USUV was first detected in the UK in 2020 and has become endemic, having been detected in either birds and/or mosquitoes every subsequent year. Importantly, the vector competence of indigenous mosquitoes for the circulating UK (London) USUV strain at representative regional temperatures is still to be elucidated. This study assessed the vector competence of five field-caught mosquito species/biotypes, Culex pipiens biotype molestus, Culex pipiens biotype pipiens, Culex torrentium, Culiseta annulata and Aedes detritus for the London USUV strain, with infection rates (IR) and transmission rates (TR) evaluated between 7 to 28 days post-infection. Infection and transmission were observed in all species/biotypes aside from Ae. detritus and Cx. torrentium. For Cx. pipiens biotype molestus, transmission potential suggests these populations should be monitored further for their role in transmission to humans. Furthermore, both Cx. pipiens biotype pipiens and Cs. annulata were shown to be competent vectors at 19{degrees}C indicating the potential for geographical spread of the virus to other UK regions.

ecology↗

bioRxiv2020

Temperatures that sterilise males better predict global distributions of species than lethal temperatures

Predicting how biodiversity will respond to increased temperatures caused by climate change is vital. However, our understanding of the traits that determine species response to thermal stress remains incomplete. Laboratory measurements of lethal temperatures have successfully been used to predict global species distributions and the vulnerability of species to future climate change. However, although it has long been known that fertility is sensitive to heat stress, temperatures that cause sterility have not been incorporated into predictions about how climate change will affect biodiversity. Here we show that male sterility temperatures predict the global distributions of 43 species of Drosophila substantially better than their lethal temperatures. This strongly suggests that thermal limits to reproduction can underpin how temperature affects species distributions. High temperatures impair male fertility across a broad range of animals and plants, so many organisms may be more vulnerable to high temperatures than currently expected.

ecology↗

bioRxiv2018

Evolutionary stability of plant-pollinator networks: efficient communities, hysteresis, and a pollination dilemma

Mutualistic interactions between species such as pollination and plant-mycorrhiza interactions are ubiquitous in nature and essential for ecosystem functioning. Often dozens or even hundreds of species with different degree of specialization form complex networks of interdependence. How the complexity evolved and is maintained are fundamental questions in ecology. Here, we present a new game theoretical approach to model complex mutualistic interactions, which we apply to pollination networks. The theoretical analysis revealed multiple evolutionary stable network structures that form a gradient from generalism toward specialism with increasing availability of pollination service. In particular, we found that efficient communities evolve only under pollination oversupply, but that pollination shortage selects for inefficient network structures due to a pollination dilemma. These results suggest that availability of pollination services is a key factor structuring pollination networks and offer a new explanation for the geographical differences in pollination faunas that have long been recognized by ecologists. The study bridges the gap between network studies, game theory, and the natural history of pollination, which have hitherto been studied largely independently.

ecology↗