Biology LettersPub Date : 2025-10-01Epub Date: 2025-10-15DOI: 10.1098/rsbl.2025.0388
Peter J Edmunds, Howard R Lasker
{"title":"A long-term perspective to the effects of the 2023 marine heat wave on stony corals in the Caribbean.","authors":"Peter J Edmunds, Howard R Lasker","doi":"10.1098/rsbl.2025.0388","DOIUrl":"10.1098/rsbl.2025.0388","url":null,"abstract":"<p><p>Marine heat waves (MHW) are a leading cause of death for stony corals, and it is reasonable to expect that a record-breaking MHW would negatively impact coral communities; 2023-2024 provided a test of this assertion in St John, US Virgin Islands, where an intense MHW brought temperatures of 30.6°C and degree-heating weeks of 23.23°C-weeks. On reefs where coral cover has been low for decades, the 2023/2024 MHW did not have discernable effects on coral cover. Nonetheless, there was a trend between 2023 and 2024 for mean coral cover to decline by small absolute (≤ 3%), but large relative (13-27%) amounts, with these changes affecting multiple genera and perturbing coral assemblages. These trends are eclipsed by the massive changes that have affected these coral communities since 1987; the 2023/2024 MHW was the latest in a series of disturbances transitioning these reefs to low coral cover. This MHW did not statistically depress coral cover, but it changed coral assemblages, intensifying the ecological perils of rarity, extirpation and perhaps local extinction.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 10","pages":"20250388"},"PeriodicalIF":3.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12520772/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145290835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biology LettersPub Date : 2025-10-01Epub Date: 2025-10-15DOI: 10.1098/rsbl.2025.0284
Nazley Liddle, Marc T Freeman, Susan J Cunningham, Shannon R Conradie, Andrew E McKechnie
{"title":"A heat-sensitive songbird's risk of lethal hyperthermia increases with humidity.","authors":"Nazley Liddle, Marc T Freeman, Susan J Cunningham, Shannon R Conradie, Andrew E McKechnie","doi":"10.1098/rsbl.2025.0284","DOIUrl":"10.1098/rsbl.2025.0284","url":null,"abstract":"<p><p>Frequent and intense heatwaves are causing heat-related avian mass mortality events to become more common, but the role of elevated humidity as a contributing factor remains unclear. Here, we quantified the effect of humidity on risks of lethal hyperthermia for blue waxbills (<i>Uraeginthus angolensis</i>), the species most common among the victims of South Africa's first documented heat-related mass mortality event involving wild bird populations. We quantified waxbills' body temperature (<i>T</i><sub><i>b</i></sub>), metabolic heat production and evaporative heat loss at air temperatures (<i>T</i><sub>air</sub>) approaching and surpassing normothermic <i>T</i><sub><i>b</i></sub> in dry (1.1 ± 0.9 g m<sup>-3</sup>) and humid (21.3 ± 0.4 g m<sup>-3</sup>) air. The humid treatment was associated with significant declines in evaporative cooling capacity, and maximum <i>T</i><sub>air</sub> tolerated by waxbills was approximately 2°C lower (45.7°C) compared to the dry air treatment (47.9°C). A model of end-Century exposure for the waxbills reveals that elevated humidity could increase the risks of lethal hyperthermia by threefold to sevenfold in some parts of southern Africa.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 10","pages":"20250284"},"PeriodicalIF":3.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12522157/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145290861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biology LettersPub Date : 2025-10-01Epub Date: 2025-10-22DOI: 10.1098/rsbl.2025.0158
Aditya Kurre, Larisa R G DeSantis
{"title":"Lost giants, lost functions: palaeodietary insights into the ecological niches of Pleistocene ground sloths.","authors":"Aditya Kurre, Larisa R G DeSantis","doi":"10.1098/rsbl.2025.0158","DOIUrl":"10.1098/rsbl.2025.0158","url":null,"abstract":"<p><p>Ground sloths were terrestrial megafauna that inhabited the Western Hemisphere. While they are inferred to have been browsers and grazers based on craniodental morphology, it is plausible that they performed a wide range of ecological functions, including seed dispersal, bioturbation and nutrient cycling. Understanding ground sloth ecology is challenging due to their enamel-free dentition, which poses limitations to palaeodietary methods, like stable isotope analysis, due to the increased probability of diagenesis in more porous tissues. Here, we conduct dental microwear texture analysis on <i>Paramylodon harlani</i> and <i>Nothrotheriops shastensis</i> specimens from the La Brea Tar Pits in southern California to compare these species to each other, to co-occurring megafauna and to modern analogues to clarify ground sloth dietary ecology. DMTA of <i>P. harlani</i> (i.e. low anisotropy and high complexity) and <i>N. shastensis</i> (i.e. low anisotropy and low complexity) suggests that <i>P. harlani</i> consumed significantly harder foods (e.g. tubers, roots, seeds, fruit pits) than <i>N. shastensis</i>. Findings underscore that these species were not functional replicates of each other or of co-occurring browsers and grazers (e.g. camels and bison). Considering the high degree of dietary overlap in extant folivorous sloths, the extinction of giant ground sloths represents a true loss of ecological function.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 10","pages":"20250158"},"PeriodicalIF":3.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12539959/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145343095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biology LettersPub Date : 2025-10-01Epub Date: 2025-10-15DOI: 10.1098/rsbl.2025.0289
Raquel O Vasconcelos, Daniel Alves, M Clara P Amorim, Paulo J Fonseca
{"title":"Auditory representation of conspecific calls improves throughout ontogeny in a singing fish.","authors":"Raquel O Vasconcelos, Daniel Alves, M Clara P Amorim, Paulo J Fonseca","doi":"10.1098/rsbl.2025.0289","DOIUrl":"10.1098/rsbl.2025.0289","url":null,"abstract":"<p><p>A central question in understanding acoustic communication systems is how auditory processing develops relative to vocal differentiation. While the development of auditory processing of conspecific vocalizations has been studied in songbirds and mammals, it remains unexplored in fish. The Lusitanian toadfish (<i>Halobatrachus didactylus</i>) is an highly soniferous fish that exhibits sound production early in ontogeny, representing an ideal model to investigate the development of the vertebrate auditory-vocal system. Based on the auditory evoked potential (AEP) recording technique, we evaluated differences in auditory representation of boatwhistles (reproductive, agonistic and juvenile calls) and territorial grunts between different-sized toadfish groups-small juveniles (1.4-1.8 cm standard length), large juveniles (6.7-10.6 cm) and adults (up to 36 cm). Significant ontogenetic improvements were found in representing temporal patterns of boatwhistles (response latency and duration) and grunts (latency, pulse period and duration), as well as in detecting boatwhistle amplitude modulation. These acoustic parameters can potentially function as social cues for individual quality, motivation and mate choice. We present the first evidence of ontogenetic refinement in resolving fine features of conspecific calls in a fish species, suggesting this may be a conserved mechanism enhancing social communication across vocal vertebrates.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 10","pages":"20250289"},"PeriodicalIF":3.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12520764/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145290902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biology LettersPub Date : 2025-10-01Epub Date: 2025-10-15DOI: 10.1098/rsbl.2025.0293
Madison A Rittinger, Rafael Lucas Rodríguez
{"title":"Instinct to insight: a variation-based framework to test hypotheses about how animals solve problems.","authors":"Madison A Rittinger, Rafael Lucas Rodríguez","doi":"10.1098/rsbl.2025.0293","DOIUrl":"10.1098/rsbl.2025.0293","url":null,"abstract":"<p><p>Problem-solving is an integral part of most animals' lives. There are generally four types of solutions animals may use: innate, learned previously, learned de novo or insightful. Identifying the types of solutions animals use can be difficult, especially with the trend of having increasingly difficult requirements to test hypotheses in this field. These requirements often amount to proving a negative, which may be impossible. Therefore, here we develop a novel framework for testing hypotheses that can help distinguish the types of solutions animals may use that does not require proving a negative. This framework is based on distinct patterns of <i>qualitative</i> and <i>quantitative</i> variation <i>between</i> and <i>within</i> individuals. Because this framework does not require knowledge of animal's prior history nor that the problem be evolutionarily novel, it can be used with a variety of animals, experimental designs and settings. We suggest this framework could serve as a valuable tool in expanding how we study animal problem-solving, especially in the types of animals studied. Studying problem-solving in a wide variety of animals would allow us to form a better understanding of the problem-solving abilities different brain sizes and structures confer and, more broadly, the evolution of those abilities.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 10","pages":"20250293"},"PeriodicalIF":3.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12520766/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145290981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biology LettersPub Date : 2025-09-01Epub Date: 2025-09-17DOI: 10.1098/rsbl.2025.0239
Harini Kannan, King L Chow
{"title":"Chemosensory adaptations in <i>Caenorhabditis</i> males during the establishment of androdioecy.","authors":"Harini Kannan, King L Chow","doi":"10.1098/rsbl.2025.0239","DOIUrl":"10.1098/rsbl.2025.0239","url":null,"abstract":"<p><p><i>Caenorhabditis elegans</i> has evolved from its dioecious ancestors to adopt an androdioecious reproductive strategy. In this process, ancestral female <i>C. elegans</i> acquired genetic modifications that enabled self-sperm generation, self-sperm activation and a reduced reliance on sexual reproduction. However, how males have adapted during this transition from dioecy to androdioecy is less explored. Using <i>Caenorhabditis</i> species, we demonstrated that androdioecious hermaphrodites exhibit attenuated sex pheromone potency, while androdioecious males show heightened olfactory habituation and diminished mate exploration capabilities. The behaviour of androdioecious males can be reverted to resemble that of dioecious males by replacing the SRD-1 receptor with its dioecious orthologues. This intrinsic characteristic is contingent upon the C-terminal cytoplasmic domain of the receptor. We propose a theoretical framework where <i>C. elegans</i> males have accumulated genetic variations in their pheromone receptor, leading to altered chemosensory perception of the opposite sex, which confers a selective advantage favouring hermaphroditism. Our study provides insights into overlooked male traits, shaped by changes in chemosensory signalling. The findings underscore the capacity of chemosensory variations to influence how organisms perceive critical ecological factors, eventually facilitating the emergence and stabilization of hermaphroditism.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 9","pages":"20250239"},"PeriodicalIF":3.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12440622/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145074235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biology LettersPub Date : 2025-09-01Epub Date: 2025-09-24DOI: 10.1098/rsbl.2025.0411
Plamen S Andreev, Min Zhu, Lars Brakenhoff, Qiang Li, Wenjin Zhao, Lijian Peng, Federica Marone, Richard P Dearden, Martin Rücklin
{"title":"The shoulder girdle of early chondrichthyans grew by skeletal remodelling.","authors":"Plamen S Andreev, Min Zhu, Lars Brakenhoff, Qiang Li, Wenjin Zhao, Lijian Peng, Federica Marone, Richard P Dearden, Martin Rücklin","doi":"10.1098/rsbl.2025.0411","DOIUrl":"10.1098/rsbl.2025.0411","url":null,"abstract":"<p><p>A distinct shoulder region, defined by endoskeletal and dermal girdles and associated pectoral musculature, is a major evolutionary adaptation of jawed vertebrates. In teleost model species, the large (macromeric) pectoral dermal bones can be derived from multiple embryonic tissues, identifying the shoulder of osteichthyans as a developmentally complex area at the head-trunk boundary. The absence of bone in living chondrichthyans makes Palaeozoic stem groups capable of dermal ossification key to understanding the underpinnings of skeletal growth in the shoulder of crown gnathostomes (osteichthyans and chondrichthyans). Here, using synchrotron X-ray tomography we demonstrate that individual pectoral plates in the oldest unequivocal jawed vertebrate, the Silurian (c. 439 Mya) chondrichthyan <i>Fanjingshania renovata</i>, develop from five separate growth centres. These centres correspond to pectoral bony spines that fuse neighbouring dermal scales into a pinnal plate and their expansion is accompanied by cyclical resorption and remodelling of bone and dentine. Our phylogenetic analyses support an interpretation of these processes as crown and stem gnathostome characters that co-occur only in the shoulder girdle of stem chondrichthyans. The systematic hard tissue remodelling in <i>Fanjingshania</i> reveals an unexpected growth dynamic within chondrichthyans that relates to the formation of a macromeric skeleton through integration of modular elements.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 9","pages":"20250411"},"PeriodicalIF":3.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12459293/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145129834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biology LettersPub Date : 2025-09-01Epub Date: 2025-09-03DOI: 10.1098/rsbl.2025.0176
Yixun Zhao, Pengying Lu, Xiao Wang, Ming Yin
{"title":"Bidirectional optimization of firing rate in a mouse neuronal brain-machine interface.","authors":"Yixun Zhao, Pengying Lu, Xiao Wang, Ming Yin","doi":"10.1098/rsbl.2025.0176","DOIUrl":"10.1098/rsbl.2025.0176","url":null,"abstract":"<p><p>Neuroplasticity enables the brain to adapt neural activity, but whether this can be harnessed for abstract optimization tasks like seeking curve extrema remains unclear. Here, we used a brain-machine interface in mice, pairing auditory feedback of neuronal firing rate with water rewards, to investigate whether motor cortex neurons can optimize activity along a unimodal curve ([Formula: see text]). The curve maps firing rate ([Formula: see text]) to sound frequency increase speed ([Formula: see text]), where the curve extremum accelerates reward acquisition. Over conditioning sessions, mice learned to modulate firing rates towards this peak, reducing reward time from 18.64 ± 7.30 s to 11.59 ± 4.38 s and increasing high-response events from 66 to 104 occurrences. Putative neurons increasingly prioritized high-response intervals, with positive proportion increments in upper intervals versus negative trends in lower ones. These findings demonstrate that cortical neurons can dynamically optimize activity along non-monotonic reward landscapes, revealing neuroplasticity as a substrate for adaptive self-optimization. This expands our understanding of how the brain learns abstract rules via feedback, with implications for neuroprosthetic design that leverage neural adaptability.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 9","pages":"20250176"},"PeriodicalIF":3.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12405940/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144941604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biology LettersPub Date : 2025-09-01Epub Date: 2025-09-17DOI: 10.1098/rsbl.2025.0366
Michael Constantine Granatosky, Melody Young, Gabrielle A Hirschkorn, Julie C McKinney, Kay Welser, Edwin Dickinson
{"title":"Grasping performance in primates does not align with preferred substrate use.","authors":"Michael Constantine Granatosky, Melody Young, Gabrielle A Hirschkorn, Julie C McKinney, Kay Welser, Edwin Dickinson","doi":"10.1098/rsbl.2025.0366","DOIUrl":"10.1098/rsbl.2025.0366","url":null,"abstract":"<p><p>Arboreal locomotion presents considerable mechanical challenges, requiring animals to maintain stability on narrow supports. While some species rely on gait adjustments, others use grasping autopodia to counteract toppling torques. We investigated how substrate size affects grasping force in strepsirrhine primates-a lineage regarded as a model for early primates and known for fine-branch arboreal locomotion. Using a custom apparatus, we measured <i>in vivo</i> grip strength across three substrate diameters (small, medium and large) in 11 species. In both hands and feet, grip strength peaked on medium-sized substrates-those allowing optimal digital wrapping-and declined on small and large diameters. These patterns remained significant after controlling for phylogeny, body size, sex and age. Despite weaker performance on small substrates, strepsirrhines commonly navigate thin terminal branches in nature, suggesting an ecological mismatch between peak grasping performance and substrate use. This implies that powerful digital grasping may be less critical for arboreal stability than often assumed. Instead, whole-body mechanics and precise limb placement likely compensate when grip is reduced. Rather than maximizing force, the primate hand appears adapted for versatility-supporting the broader principle that evolutionary success often reflects functional adequacy and adaptability over specialization for force production.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 9","pages":"20250366"},"PeriodicalIF":3.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12441750/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145074261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biology LettersPub Date : 2025-09-01Epub Date: 2025-09-17DOI: 10.1098/rsbl.2025.0342
Robert William Elwood
{"title":"Changing priorities about protective shelters: a review of a key method to investigate possible pain in crustaceans.","authors":"Robert William Elwood","doi":"10.1098/rsbl.2025.0342","DOIUrl":"10.1098/rsbl.2025.0342","url":null,"abstract":"<p><p>Testing if non-human taxa experience pain is difficult because we need to exclude the possibility that responses are nociceptive reflexes. One approach is to identify an essential, high priority, resource and then ask if the animal will abandon and subsequently avoid that resource if it is paired with a noxious stimulus. This approach has been used with crustaceans that hide in dark shelters and electric shocks have been used as noxious stimuli. A range of species show escape responses and avoid shelters if the shock is presented within, and these responses increase with increasing voltage or repetition of shocks. Crustaceans also switch to using alternative shelters and appear to dramatically alter their behavioural priorities. Animals shocked outside of a shelter, however, subsequently increase their use of shelters and benefit from reduced predation. These changes in priorities cannot be due only to nociceptive reflexes because they persist long after the cessation of the stimulus. Increasing the apparent costs of leaving a shelter decreases the probability of leaving, indicating that, by taking into account costs, they are responding via behavioural decisions and not reflexes. This provides a method to determine how much the animal will pay to avoid the shocks and similar techniques should provide powerful ways to examine potential pain in different taxa.</p>","PeriodicalId":9005,"journal":{"name":"Biology Letters","volume":"21 9","pages":"20250342"},"PeriodicalIF":3.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12440613/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145074283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}