Shifting activity to cooler times of day buffers animals from increased heat and aridity under climate change. Conversely, when resources are limited, some nocturnal species become more diurnal, reducing energetic costs of keeping warm at night. Aardvarks (Orycteropus afer) are nocturnal, obligate ant-and termite-eating mammals which may be threatened directly by increasing heat and aridity, or indirectly by the effects of climate change on their prey. We hypothesised that the minimum 24-h body temperature of aardvarks would decline during energy scarcity, and that aardvarks would extend their active phases to compensate for reduced resource availability, possibly resulting in increased diurnal activity when aardvarks were energetically compromised. To measure their thermoregulatory patterns and foraging activity, we implanted abdominal temperature and activity data loggers into 12 adult aardvarks and observed them for varying durations over 3 years in the Kalahari. Under non-drought conditions, aardvarks tightly controlled their 24-h body temperature rhythm (mean amplitude of the 24-h body temperature rhythm was 1.8 ± 0.3 • C during summer and 2.1 ± 0.1 • C during winter) and usually were nocturnal. During a summer drought, aardvarks relaxed the precision of body temperature regulation (mean 24-h amplitude 2.3 ± 0.4 • C) and those that subsequently died shifted their activity to progressively earlier times of day in the weeks before their deaths. Throughout the subsequent winter, the aardvarks' minimum 24-h body temperatures declined, causing exaggerated heterothermy (4.7 ± 1.3 • C; absolute range 24.7 to 38.8 • C), with one individual's body temperature varying by 11.7 • C within 8 h. When body temperatures were low, aardvarks often emerged from burrows during daytime, and occasionally returned before sunset, resulting in completely diurnal activity. Aardvarks also shortened their active periods by 25% during food scarcity, likely to avoid energetic costs incurred by foraging. Despite their physiological and behavioural

In mammals, myrmecophagy (ant and termite consumption) represents a striking example of dietary convergence. This trait evolved independently at least five times in placentals with myrmecophagous species comprising aardvarks, anteaters, some armadillos, pangolins, and aardwolves. The gut microbiome plays an important role in dietary adaptation, and previous analyses of 16S rRNA metabarcoding data have revealed convergence in the composition of the gut microbiota among some myrmecophagous species. However, the functions performed by these gut bacterial symbionts and their potential role in the digestion of prey chitinous exoskeletons remain open questions. Using long- and short-read sequencing of fecal samples, we generated 29 gut metagenomes from nine myrmecophagous and closely related insectivorous species sampled in French Guiana, South Africa, and the USA. From these, we reconstructed 314 high-quality bacterial genome bins of which 132 carried chitinase genes, highlighting their potential role in insect prey digestion. These chitinolytic bacteria belonged mainly to the family Lachnospiraceae, and some were likely convergently recruited in the different myrmecophagous species as they were detected in several host orders (i.e.,Enterococcus faecalis,Blautiasp), suggesting that they could be directly involved in the adaptation to myrmecophagy. Others were found to be more host-specific, possibly reflecting phylogenetic constraints and environmental influences. Overall, our results highlight the potential role of the gut microbiome in chitin digestion in myrmecophagous mammals and provide the basis for future comparative studies performed at the mammalian scale to further unravel the mechanisms underlying the convergent adaptation to myrmecophagy.

<p>The Intergovernmental Panel on Climate Change (IPCC) produces assessment reports on climate change, spanning physical climate science, climate impacts and adaptation, and mitigation. These reports draw upon scientific, technical and socio-economic information and are produced by interdisciplinary and international author teams. The reports, including their glossaries, are used by diverse audiences across the natural and social sciences, policy and practice, and education. IPCC report glossaries are an invaluable resource in their own right, covering the domains of each report and providing rigorous definitions for terms that are oft-used in public discourse.</p><p><br>The IPCC is currently in its Sixth Assessment Cycle (AR6), for which it has already released three Special Reports, and is currently preparing three Working Group (WG) Reports and a Synthesis Report to be released in 2021/22. Since each report and report chapter is written by a different author team, ensuring consistency in approach and conclusions across and within each report represents a key challenge. An important contribution towards achieving consistency is the development of single definitions for terms to be used across several reports. To facilitate the development of such definitions, the IPCC Secretariat and Technical Support Units have created custom software for internal author use, termed the Collaborative Online Glossary System (COGS). In addition, a public portal for IPCC glossaries (https://apps.ipcc.ch/glossary/) has been developed, where AR5 and approved AR6 report glossaries are hosted and can be readily searched. Here we discuss these tools within the context of interdisciplinary collaboration in climate change assessment. We also highlight the benefits of having consistent definitions when working more broadly at the water-energy-land nexus.</p>