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Recent studies demonstrate a strong influence of soil age on long-term silicon (Si) dynamics in terrestrial ecosystems, but how variation in ecosystem water balance and soil parent material impact this trajectory is unknown. We addressed this by studying a 2-million-year dune chronosequence in southwestern Australia characterized by a positive water balance (+ 50 mm year−1) and a lower carbonate concentration in the parent sand (5%) compared with two chronosequences already characterized (− 900 and − 750 mm year−1; 88 and 74%). We sampled soils from the progressive and retrogressive phases of ecosystem development to quantify pedogenic reactive Si (extracted in ammonium oxalate and oxalic acid), phytoliths (biogenic Si), and plant-available Si (extracted in dilute CaCl2). Silicon mobilization was buffered by carbonate in the early stages of the two carbonate-rich drier chronosequences, as previously highlighted, but not in the carbonate-poor wetter chronosequence. Reactive pedogenic Si and plant-available Si did not peak at intermediate stages in the carbonate-poor wetter chronosequence, where almost no clay formation occurred, as it did in the carbonate-rich drier chronosequences during clay formation after carbonate loss. This is probably due to a combination of lower content of weatherable minerals in the soil parent material and higher weathering rates. Phytolith stocks were similar across the three chronosequences, suggesting that a climate-driven increase in biomass and associated phytolith production in wetter sites counterbalance the higher phytolith dissolution rates and physical translocation. Together, these results demonstrate that the initial carbonate concentration in the soil parent material and subsequent mineralogical evolution drive long-term soil Si dynamics, and suggest a significant influence of climate-induced variation in biomass production on the Si biological feedback loop, even in old and highly desilicated environments. [ABSTRACT FROM AUTHOR]

Sleep is a prominent, seemingly universal animal behavior. Although sleep maintains optimal waking performance, the biological drive to sleep may be incompatible with the life history of some species. In a multi-year study on semelparous marsupials in Australia, we provide the first direct evidence of ecological sleep restriction in a terrestrial mammal. Dusky (Antechinus swainsonii) and agile (A. agilis) antechinus have an unusual reproductive strategy characterized by the synchronous death of all males at the end of their only breeding season. Using accelerometry, electrophysiology, and metabolomics, we show that males, but not females, increase their activity during the breeding season by reducing sleep. In a trade-off between the neurophysiological requirements for sleep and evolutionary necessity for reproduction, strong sexual selection might drive males to sacrifice sleep to increase access to fertile females and ultimately maximize their fitness., Competing Interests: Declaration of interests Authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Sclerotinia stem rot ( Sclerotinia sclerotiorum) is a serious disease in oilseed Brassica crops worldwide. In this study, temperature adaptation in isolates of S. sclerotiorum collected from differing climatic zones is reported for the first time on any crop. Sclerotinia sclerotiorum isolates from oilseed rape ( Brassica napus) crops in warmer northern agricultural regions of Western Australia ( WW3, UWA 7S3) differed in their reaction to temperature from those from cooler southern regions ( MBRS-1, UWA 10S2) in virulence on Brassica carinata, growth on agar, and oxalic acid production. Increasing temperature from 22/18°C (day/night) to 28/24°C increased lesion diameter on cotyledons of B. carinata BC054113 more than tenfold for warmer region isolates, but did not affect lesion size for cooler region isolates. Mean lesion length averaged across two B. carinata genotypes (resistant and susceptible) fell from 4·6 to 2·4 mm for MBRS-1 when temperature increased from 25/21°C to 28/24°C but rose for WW3 (2·35 and 3·21 mm, respectively). WW3, usually designated as low in virulence, caused as much disease on stems at 28/24°C as MBRS-1, historically designated as highly virulent. Isolates collected from cooler areas grew better at low temperatures on agar. While all grew on potato dextrose agar between 5 and 30°C, with maximum growth at 20-25°C, growth was severely restricted above 32°C, and only UWA 7S3 grew at 35°C. Oxalate production increased as temperature increased from 10 to 25°C for isolates MBRS-1, WW3 and UWA 7S3, but declined from a maximum level of 101 mg g−1 mycelium at 20°C to 24 mg g−1 mycelium at 25°C for UWA 10S2. [ABSTRACT FROM AUTHOR]