This is a repository copy of Temperatures that sterilize males better match global species distributions than lethal temperatures.

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There is increasing emphasis on the use of new analytical approaches in subject analysis and classification, particularly in respect to minimal sample preparation. Here, we demonstrate that rapid evaporative ionization mass spectrometry (REIMS), a method that captures metabolite mass spectra after rapid combustive degradation of an intact biological specimen, generates informative mass spectra from several arthropods, and more specifically, is capable of discerning differences between species and sex of several adult Drosophila species. A model including five Drosophila species, built using pattern recognition, achieves high correct classification rates (over 90%) using test datasets and is able to resolve closely related species. The ease of discrimination of male and female specimens also demonstrates that sex-specific differences reside in the REIMS metabolite patterns, whether analysed across all five species or specifically for D. melanogaster. Further, the same approach can correctly discriminate and assign Drosophila species at the larval stage, where these are morphologically highly similar or identical. REIMS offers a novel approach to insect typing and analysis, requiring a few seconds of data acquisition per sample and has considerable potential as a new tool for the field biologist.

The response of soil microbial communities to a changing climate will impact global biogeochemical cycles, potentially leading to positive and negative feedbacks. However, our understanding of how soil microbial communities respond to climate change and the implications of these changes for future soil function is limited. Here, we assess the response of soil bacterial and fungal communities to long-term experimental climate change in a heathland organo-mineral soil. We analysed microbial communities using Illumina sequencing of the 16S rRNA gene and ITS2 region at two depths, from plots undergoing 4 and 18 years of in situ summer drought or warming. We also assessed the colonisation of Calluna vulgaris roots by ericoid and dark septate endophytic (DSE) fungi using microscopy after 16 years of climate treatment. We found significant changes in both the bacterial and fungal communities in response to drought and warming, likely mediated by changes in soil pH and electrical conductivity. Changes in the microbial communities were more pronounced after a longer period of climate manipulation. Additionally, the subsoil communities of the long-term warmed plots became similar to the topsoil. Ericoid mycorrhizal colonisation decreased with depth while DSEs increased; however, these trends with depth were removed by warming. We largely ascribe the observed changes in microbial communities to shifts in plant cover and subsequent feedback on soil physicochemical properties, especially pH. Our results demonstrate the importance of considering changes in soil microbial responses to climate change across different soil depths and after extended periods of time.

18Climate change is well understood to be a major threat to biodiversity, but sublethal impacts of 19 high temperatures, such as reduced fertility, have been poorly studied. We examined a panel of 20 43 Drosophila species, finding that 19 experience significant fertility loss at temperatures up to 21 4.3 o C cooler than their lethal temperature limits. We found that upper thermal fertility limits 22 explain global distributions of species better than limits based on lethal temperatures. This 23 suggests that limits to reproduction, rather than limits to survival, can underpin species 24 distributions in nature. Given that high temperatures impair male fertility across a broad range of 25 animals and plants, many species may be at increased risk of extinction due to inability to 26 reproduce at high temperatures.27 28 One Sentence Summary: 29 Species' distributions and response to climate change are strongly affected by the temperature at 30 which they lose fertility. 31 3 Main Text: 32 We urgently need to understand how rises in temperature will impact biodiversity(1). To do this 33 we must understand the physiological, behavioral and evolutionary factors that underpin 34 species' current thermal distributions(2, 3). Laboratory-derived estimates of the highest 35 temperatures at which an organism can function provide measures of species' thermal 36 tolerances(4). These measures of upper thermal limits have improved the accuracy of 37 functional species distribution models(5) which can be extrapolated to climate change 38 scenarios, allowing ecologists to forecast future species distributions(6). Accurate predictions of 39 species' distributions are invaluable for prioritizing conservation efforts(7) and predicting the 40 invasion of disease vectors(8). 42Upper thermal tolerance limits are usually based on the temperatures that cause loss of 43 coordinated movement, coma, respiratory failure, or death: the species' critical thermal limit. 44Despite these being measured in artificial laboratory conditions, critical limits correlate 45 reasonably well with species' distributions(4) and have been used to estimate species' capacity 46 to tolerate temperature increases across their current distribution range; their 'thermal safety 47 margins'(3). However, persistence of populations is not determined solely by survival, but also 48 by reproduction. There is evidence that sub-lethal temperatures cause losses in fertility in 49 plants(9), insects(10-12), fish(13), aquatic invertebrates(14), birds(15) and mammals, including 50 humans(16). These effects include direct impacts on physiological processes (10, 15, 17) and 51 indirect influences via changes in behavior and phenology(18). Previously, we proposed that 52 temperatures at which fertility is lost, the thermal fertility limits (TFLs) (18), may be a critical 53 4 but understudied part of species' true upper thermal limits. If TFLs are lower than critical limits, 54 then many organisms will be more vulnerable to climate change than currently thought. If TF...