Pub Date : 2026-01-08DOI: 10.1016/j.fooweb.2026.e00437
Carmen Kowarik , Pierre Chanut , Matthias Pilecky , Christopher T. Robinson
An increasing number of streams are becoming intermittent due to global warming and water abstraction. The transfer of omega-3 polyunsaturated fatty acids (PUFAs)—particularly eicosapentaenoic acid (EPA)—from aquatic to terrestrial systems is a key ecosystem service likely to be affected by increasing intermittency. Here, we investigated how flow intermittency affected EPA transfer to riparian spiders along 9 headwater streams of an alpine catchment (Val Roseg, Switzerland) with different degrees of intermittency. We used fatty acid analysis to test if there were differences in fatty acid content in spiders sampled along streams varying in degree of intermittency. In addition, we used compound-specific isotope analysis (2H-CSIA) to determine the origin of different fatty acids present in spiders. We found altered fatty acid profiles, characterized by lower content of the omega-3 fatty acids EPA and docosahexaenoic acid (DHA) in spiders collected along streams that dried periodically during multiple times of the year. In contrast, spiders from streams experiencing seasonal drying during winter did not show altered fatty acid profiles compared to spiders from perennial streams. δ2H values indicated that fatty acid sources also differed between streams varying in intermittency. Our results suggest that stream intermittency affects subsidy transfers from aquatic to riparian ecosystems, indicating far-reaching consequences for riparian communities in resource poor alpine environments, but potentially also lower elevation fluvial systems.
{"title":"Influence of stream intermittency on PUFA transfer to alpine riparian spiders","authors":"Carmen Kowarik , Pierre Chanut , Matthias Pilecky , Christopher T. Robinson","doi":"10.1016/j.fooweb.2026.e00437","DOIUrl":"10.1016/j.fooweb.2026.e00437","url":null,"abstract":"<div><div>An increasing number of streams are becoming intermittent due to global warming and water abstraction. The transfer of omega-3 polyunsaturated fatty acids (PUFAs)—particularly eicosapentaenoic acid (EPA)—from aquatic to terrestrial systems is a key ecosystem service likely to be affected by increasing intermittency. Here, we investigated how flow intermittency affected EPA transfer to riparian spiders along 9 headwater streams of an alpine catchment (Val Roseg, Switzerland) with different degrees of intermittency. We used fatty acid analysis to test if there were differences in fatty acid content in spiders sampled along streams varying in degree of intermittency. In addition, we used compound-specific isotope analysis (<sup>2</sup>H-CSIA) to determine the origin of different fatty acids present in spiders. We found altered fatty acid profiles, characterized by lower content of the omega-3 fatty acids EPA and docosahexaenoic acid (DHA) in spiders collected along streams that dried periodically during multiple times of the year. In contrast, spiders from streams experiencing seasonal drying during winter did not show altered fatty acid profiles compared to spiders from perennial streams. δ<sup>2</sup>H values indicated that fatty acid sources also differed between streams varying in intermittency. Our results suggest that stream intermittency affects subsidy transfers from aquatic to riparian ecosystems, indicating far-reaching consequences for riparian communities in resource poor alpine environments, but potentially also lower elevation fluvial systems.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"46 ","pages":"Article e00437"},"PeriodicalIF":1.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.fooweb.2025.e00436
Fabrício H. Oda , Fred Muller , Leandro O. Drummond , Rodney M.P. Couto , Silionamã P. Dantas , Jeremiah J. Barbosa , Werther P. Ramalho , Ygor Ribeiro Lima , Maiara C. Miguel , Amanda M. Cruz , Anderson C. Branco , Murilo S. Queiroz , Ángel Sosa-Bartuano , Camila Aoki , Marcelo N.C. Kokubum , Antonio D. Brescovit
The Neotropics have the largest diversity of anurans and spiders in the world, and the current literature includes many reports of spiders preying on anurans from this area. Here, we describe 31 previously unpublished records of predation documented during occasional observations in Brazil, Costa Rica, Guatemala, Panama and Peru, and review the published predation reports to update the list of Neotropical anuran species reported as spider prey. From this updated database, we summarize the taxonomic and geographic distribution of these predation records to identify the anuran families and species most reported to be victims of spider predation, as well as the countries and biogeographic regions with the highest number of predation events to provide a more comprehensive understanding of the role of anurans as spider prey in the Neotropics. The new records increased the number of anuran species known as spider prey in the Neotropics from 143 to 195. This study paves the way for further field studies in poorly sampled ecoregions and will serve as a reference database for new reports of anuran predation by spiders.
{"title":"Anurans as prey of spiders in the neotropics: New records and updated interactions","authors":"Fabrício H. Oda , Fred Muller , Leandro O. Drummond , Rodney M.P. Couto , Silionamã P. Dantas , Jeremiah J. Barbosa , Werther P. Ramalho , Ygor Ribeiro Lima , Maiara C. Miguel , Amanda M. Cruz , Anderson C. Branco , Murilo S. Queiroz , Ángel Sosa-Bartuano , Camila Aoki , Marcelo N.C. Kokubum , Antonio D. Brescovit","doi":"10.1016/j.fooweb.2025.e00436","DOIUrl":"10.1016/j.fooweb.2025.e00436","url":null,"abstract":"<div><div>The Neotropics have the largest diversity of anurans and spiders in the world, and the current literature includes many reports of spiders preying on anurans from this area. Here, we describe 31 previously unpublished records of predation documented during occasional observations in Brazil, Costa Rica, Guatemala, Panama and Peru, and review the published predation reports to update the list of Neotropical anuran species reported as spider prey. From this updated database, we summarize the taxonomic and geographic distribution of these predation records to identify the anuran families and species most reported to be victims of spider predation, as well as the countries and biogeographic regions with the highest number of predation events to provide a more comprehensive understanding of the role of anurans as spider prey in the Neotropics. The new records increased the number of anuran species known as spider prey in the Neotropics from 143 to 195. This study paves the way for further field studies in poorly sampled ecoregions and will serve as a reference database for new reports of anuran predation by spiders.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"46 ","pages":"Article e00436"},"PeriodicalIF":1.5,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-24DOI: 10.1016/j.fooweb.2025.e00435
Nohales María, López-López Lucía, Preciado Izaskun, Rabanal Irene, Ortiz Juan José
We investigated the ingestion of preproduced plastic pellets (<3 mm), also known as nurdles, by mesopelagic teleost fish following an industrial spill near the eastern Cantabrian continental shelf. We analyzed 228 specimens from seven pelagic fish species but found no pellet ingestion. The absence of plastic ingestion is likely due to several factors, including low pellet concentrations in the sampling area, their high buoyancy keeping them beyond the fish feeding zone, or species-specific feeding selectivity. The findings of this study suggest a low occurrence of plastic pellets in the stomachs of mesopelagic fauna, though ingestion may be more likely in areas with higher pellet concentrations. This study provides a baseline for assessing mesopelagic species' responses to future plastic pellet spills.
{"title":"Setting the scene: Should we expect small pelagic fish to ingest plastic pellets?","authors":"Nohales María, López-López Lucía, Preciado Izaskun, Rabanal Irene, Ortiz Juan José","doi":"10.1016/j.fooweb.2025.e00435","DOIUrl":"10.1016/j.fooweb.2025.e00435","url":null,"abstract":"<div><div>We investigated the ingestion of preproduced plastic pellets (<3 mm), also known as nurdles, by mesopelagic teleost fish following an industrial spill near the eastern Cantabrian continental shelf. We analyzed 228 specimens from seven pelagic fish species but found no pellet ingestion. The absence of plastic ingestion is likely due to several factors, including low pellet concentrations in the sampling area, their high buoyancy keeping them beyond the fish feeding zone, or species-specific feeding selectivity. The findings of this study suggest a low occurrence of plastic pellets in the stomachs of mesopelagic fauna, though ingestion may be more likely in areas with higher pellet concentrations. This study provides a baseline for assessing mesopelagic species' responses to future plastic pellet spills.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"46 ","pages":"Article e00435"},"PeriodicalIF":1.5,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-23DOI: 10.1016/j.fooweb.2025.e00432
Diego F. Cisneros-Heredia , Elias Viteri-Basso , Jorge Brito
Understanding the feeding ecology of top avian predators is crucial to unravelling trophic interactions and informing conservation strategies. Great Horned Owl Bubo virginianus, although among the most widespread nocturnal raptors in America, remains understudied in the northern Andes. We investigated the diet of the Andean subspecies B. v. nigrescens in an inter-Andean valley of northern Ecuador and compiled a literature review of its dietary patterns across the subspecies' range in Colombia and Ecuador. We analysed 57 pellets (43 complete, 14 fragmented) collected each December from 2014 to 2017. The 106 identified prey items comprised mammals as the primary food source (73 % of items, 94 % of total estimated biomass), with Andean White-eared Opossum Didelphis pernigra (66 % of biomass) and Black Rat Rattus rattus (22 % of biomass) contributing the largest share. Smaller native and introduced rodents were also common (48 % of all items), while other groups appeared less frequently: birds (10 %), frogs (5 %), bats (3 %) and Scarabaeid beetles (12 % by count but ∼0.1 % of biomass), underscoring the owl's generalist foraging. Because our empirical sampling was restricted to a single pair and a single month per year, intra-annual shifts cannot be assessed here and some prey groups may be underrepresented; we therefore interpret patterns conservatively. A new record of predation on a young Domestic Cat Felis catus highlights adaptability to urbanised landscapes. Our literature review revealed seven studies spanning páramo to inter-Andean valleys showing similar trends across Colombia and Ecuador, with mammalian prey—often rabbits in higher elevations—dominant throughout, and highlights geographic gaps (e.g., northern Peru, large portions of Ecuador and Colombia). These findings suggest that B. v. nigrescens exhibits a flexible feeding ecology, capitalising on native and non-native prey. However, shifting land-use practices may affect prey availability and pose future challenges for this apex predator. Coordinated, year-round, multi-elevation studies would clarify seasonal variation and broader ecological dynamics, guiding conservation efforts in tropical mountain ecosystems.
了解顶级鸟类捕食者的摄食生态对于揭示营养相互作用和制定保护策略至关重要。维吉尼亚大角鸮虽然是美洲分布最广的夜间猛禽之一，但在安第斯山脉北部仍未得到充分研究。我们调查了厄瓜多尔北部安第斯山脉间山谷的安第斯亚种B. v. nigrescens的饮食，并对其在哥伦比亚和厄瓜多尔亚种范围内的饮食模式进行了文献综述。我们分析了2014年至2017年每年12月收集的57个颗粒（43个完整，14个破碎）。106种确定的猎物以哺乳动物为主要食物来源（占73%，占总估计生物量的94%），其中安第斯白耳负鼠（占生物量的66%）和黑鼠Rattus Rattus（占生物量的22%）贡献最大。较小的本地和引进的啮齿动物也很常见（占所有物种的48%），而其他类群的出现频率较低：鸟类（10%），青蛙（5%），蝙蝠（3%）和金龟甲虫（按数量计算占12%，但占生物量的0.1%），强调了猫头鹰的多面手觅食。由于我们的经验抽样仅限于一对和每年一个月，因此无法评估年度内的变化，并且某些猎物群体可能代表性不足；因此，我们保守地解释模式。一项新的捕食年轻家猫的记录突出了对城市化景观的适应性。我们的文献综述显示，跨越páramo到安第斯山脉间山谷的7项研究显示了哥伦比亚和厄瓜多尔的类似趋势，哺乳动物猎物（通常是高海拔地区的兔子）在整个地区占主导地位，并突出了地理差距（例如，秘鲁北部、厄瓜多尔和哥伦比亚的大部分地区）。这些发现表明黑芽孢杆菌表现出一种灵活的摄食生态，利用本地和非本地猎物。然而，土地利用方式的改变可能会影响猎物的可用性，并对这种顶级捕食者构成未来的挑战。协调的、全年的、多海拔的研究将阐明季节变化和更广泛的生态动态，指导热带山地生态系统的保护工作。
{"title":"Diet of the great horned owl Bubo virginianus nigrescens in an Andean forest remnant, northern Ecuador and a review of the subspecies' dietary patterns","authors":"Diego F. Cisneros-Heredia , Elias Viteri-Basso , Jorge Brito","doi":"10.1016/j.fooweb.2025.e00432","DOIUrl":"10.1016/j.fooweb.2025.e00432","url":null,"abstract":"<div><div>Understanding the feeding ecology of top avian predators is crucial to unravelling trophic interactions and informing conservation strategies. Great Horned Owl <em>Bubo virginianus</em>, although among the most widespread nocturnal raptors in America, remains understudied in the northern Andes. We investigated the diet of the Andean subspecies <em>B. v. nigrescens</em> in an inter-Andean valley of northern Ecuador and compiled a literature review of its dietary patterns across the subspecies' range in Colombia and Ecuador. We analysed 57 pellets (43 complete, 14 fragmented) collected each December from 2014 to 2017. The 106 identified prey items comprised mammals as the primary food source (73 % of items, 94 % of total estimated biomass), with Andean White-eared Opossum <em>Didelphis pernigra</em> (66 % of biomass) and Black Rat <em>Rattus rattus</em> (22 % of biomass) contributing the largest share. Smaller native and introduced rodents were also common (48 % of all items), while other groups appeared less frequently: birds (10 %), frogs (5 %), bats (3 %) and Scarabaeid beetles (12 % by count but ∼0.1 % of biomass), underscoring the owl's generalist foraging. Because our empirical sampling was restricted to a single pair and a single month per year, intra-annual shifts cannot be assessed here and some prey groups may be underrepresented; we therefore interpret patterns conservatively. A new record of predation on a young Domestic Cat <em>Felis catus</em> highlights adaptability to urbanised landscapes. Our literature review revealed seven studies spanning páramo to inter-Andean valleys showing similar trends across Colombia and Ecuador, with mammalian prey—often rabbits in higher elevations—dominant throughout, and highlights geographic gaps (e.g., northern Peru, large portions of Ecuador and Colombia). These findings suggest that <em>B. v. nigrescens</em> exhibits a flexible feeding ecology, capitalising on native and non-native prey. However, shifting land-use practices may affect prey availability and pose future challenges for this apex predator. Coordinated, year-round, multi-elevation studies would clarify seasonal variation and broader ecological dynamics, guiding conservation efforts in tropical mountain ecosystems.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"46 ","pages":"Article e00432"},"PeriodicalIF":1.5,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-20DOI: 10.1016/j.fooweb.2025.e00434
Brendan C. Ebner , John St Vincent Welch , Leo M. Cameron , Jason Schaffer , Gavin L. Butler
Riparian zones represent dynamic interfaces where amphibious predators and scavengers operate on both land and in water. Here we document observations of two individual monitor lizards (Lace monitor, Varanus varius) scavenging on the carcass of a large-bodied eastern freshwater cod (Maccullochella ikei) in the upper Clarence River catchment in northern New South Wales, Australia. In adulthood, these species function as apex predators in their respective terrestrial and aquatic habitats but predation of one on the other has not previously been documented. We use our observations to broaden conceptualisations of past and current food webs in riparian habitat along rivers in the endemic range of eastern freshwater cod. Complex interactions among aquatic and amphibious taxa and human-mediated processes (e.g. land clearing, climate change, recreational angling) warrant careful consideration if remaining remnant eastern freshwater cod subpopulations are to persist and the regional aquatic and riparian food webs preserved. Conceptualising the biotic and abiotic interactions within riparian zones is an important component of protecting riverine ecosystems. Large-bodied flagship species can potentially play an important role in engaging landholders and gaining public attention for riparian zone protection and rehabilitation.
{"title":"Lace monitors scavenge the large carcass of an endangered eastern freshwater cod","authors":"Brendan C. Ebner , John St Vincent Welch , Leo M. Cameron , Jason Schaffer , Gavin L. Butler","doi":"10.1016/j.fooweb.2025.e00434","DOIUrl":"10.1016/j.fooweb.2025.e00434","url":null,"abstract":"<div><div>Riparian zones represent dynamic interfaces where amphibious predators and scavengers operate on both land and in water. Here we document observations of two individual monitor lizards (Lace monitor, <em>Varanus varius</em>) scavenging on the carcass of a large-bodied eastern freshwater cod (<em>Maccullochella ikei</em>) in the upper Clarence River catchment in northern New South Wales, Australia. In adulthood, these species function as apex predators in their respective terrestrial and aquatic habitats but predation of one on the other has not previously been documented. We use our observations to broaden conceptualisations of past and current food webs in riparian habitat along rivers in the endemic range of eastern freshwater cod. Complex interactions among aquatic and amphibious taxa and human-mediated processes (e.g. land clearing, climate change, recreational angling) warrant careful consideration if remaining remnant eastern freshwater cod subpopulations are to persist and the regional aquatic and riparian food webs preserved. Conceptualising the biotic and abiotic interactions within riparian zones is an important component of protecting riverine ecosystems. Large-bodied flagship species can potentially play an important role in engaging landholders and gaining public attention for riparian zone protection and rehabilitation.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"46 ","pages":"Article e00434"},"PeriodicalIF":1.5,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.fooweb.2025.e00433
Viviana E. Chan-Quiñones , Carlos M. Delgado-Martínez , Eduardo Reyes-Grajales , Tristan Menant-Leclercq , David Mayor , Cintia Avendaño , Eduardo Mendoza
The role of water bodies in meeting the hydration needs of terrestrial vertebrates is widely recognized across ecosystems; however, predator-prey dynamics involving terrestrial vertebrates and semi-aquatic prey inhabiting water bodies remain understudied, particularly in Neotropical ecosystems. Understanding these trophic interactions can shed light on ecosystem functioning and ecological resilience. To contribute to addressing this knowledge gap, we present novel records of predation on amphibians and freshwater turtles by terrestrial vertebrates in two regions of the Yucatan Peninsula, Mexico. Data were collected via camera traps deployed between 2018 and 2024 at temporary water bodies in seasonally dry tropical forests. We documented 20 predation events involving mammals such as ocelots (Leopardus pardalis), raccoons (Procyon lotor), and tayras (Eira barbara), as well as raptors like the Great Black Hawk (Buteogallus urubitinga) and the Roadside Hawk (Rupornis magnirostris). In all cases, predators used their forelimbs or talons to capture and manipulate prey from shallow water, targeting anurans and Kinosternon turtles. These observations suggest that temporary water bodies serve as valuable and predictable foraging sites by concentrating semi-aquatic prey available for terrestrial predators. Our findings highlight the ecological importance of temporary aquatic habitats in supporting trophic interactions and maintaining ecosystem function within seasonally dry tropical forests.
{"title":"Beyond hydration: predation by terrestrial vertebrates on semi-aquatic prey in temporary water bodies of the Yucatan Peninsula, Mexico","authors":"Viviana E. Chan-Quiñones , Carlos M. Delgado-Martínez , Eduardo Reyes-Grajales , Tristan Menant-Leclercq , David Mayor , Cintia Avendaño , Eduardo Mendoza","doi":"10.1016/j.fooweb.2025.e00433","DOIUrl":"10.1016/j.fooweb.2025.e00433","url":null,"abstract":"<div><div>The role of water bodies in meeting the hydration needs of terrestrial vertebrates is widely recognized across ecosystems; however, predator-prey dynamics involving terrestrial vertebrates and semi-aquatic prey inhabiting water bodies remain understudied, particularly in Neotropical ecosystems. Understanding these trophic interactions can shed light on ecosystem functioning and ecological resilience. To contribute to addressing this knowledge gap, we present novel records of predation on amphibians and freshwater turtles by terrestrial vertebrates in two regions of the Yucatan Peninsula, Mexico. Data were collected via camera traps deployed between 2018 and 2024 at temporary water bodies in seasonally dry tropical forests. We documented 20 predation events involving mammals such as ocelots (<em>Leopardus pardalis</em>), raccoons (<em>Procyon lotor</em>), and tayras (<em>Eira barbara</em>), as well as raptors like the Great Black Hawk (<em>Buteogallus urubitinga</em>) and the Roadside Hawk (<em>Rupornis magnirostris</em>). In all cases, predators used their forelimbs or talons to capture and manipulate prey from shallow water, targeting anurans and <em>Kinosternon</em> turtles. These observations suggest that temporary water bodies serve as valuable and predictable foraging sites by concentrating semi-aquatic prey available for terrestrial predators. Our findings highlight the ecological importance of temporary aquatic habitats in supporting trophic interactions and maintaining ecosystem function within seasonally dry tropical forests.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"46 ","pages":"Article e00433"},"PeriodicalIF":1.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-09DOI: 10.1016/j.fooweb.2025.e00429
Diego M.P. Castro , Robert M. Hughes , Diego R. Macedo , Marcos Callisto
Understanding the ecological dynamics of upland streams along elevational gradients is crucial for conservation and management, particularly for critically endangered ecosystems, such as tropical mountains. This study examines aquatic insect basal resource assimilation and trophic niche breadth across a 500-m tropical elevation gradient (804 to 1319 m a.s.l.) in nine Brazilian upland streams. We analyzed stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in multiple food resources (leaves, coarse particulate organic matter, fine particulate organic matter, and periphyton) and aquatic insect assemblages. Our results indicate that fine particulate organic matter (FPOM) is the primary basal energy source for aquatic insects across all sites, regardless of elevation or level of canopy cover. The isotopic niche breadth of insects increased significantly with elevation, suggesting greater trophic diversity at higher altitudes. This pattern may reflect a broader spectrum of resource use and adaptability to varying environmental conditions. Additionally, we observed significant depletion in 13C and 15N values for vegetation, periphyton, and insects with increasing elevation. Our results provide insights into how basal resource quality changes along an elevation gradient and highlight the importance of small elevational gradients in shaping ecological processes. Further research is needed to explore the mechanisms driving isotopic variations along elevational gradients in tropical streams and to assess how the climate crisis affects food web dynamics in these ecosystems.
{"title":"The isotopic niche breadth of aquatic insects increases with elevation in neotropical mountain streams","authors":"Diego M.P. Castro , Robert M. Hughes , Diego R. Macedo , Marcos Callisto","doi":"10.1016/j.fooweb.2025.e00429","DOIUrl":"10.1016/j.fooweb.2025.e00429","url":null,"abstract":"<div><div>Understanding the ecological dynamics of upland streams along elevational gradients is crucial for conservation and management, particularly for critically endangered ecosystems, such as tropical mountains. This study examines aquatic insect basal resource assimilation and trophic niche breadth across a 500-m tropical elevation gradient (804 to 1319 m a.s.l.) in nine Brazilian upland streams. We analyzed stable isotope ratios of carbon (δ<sup>13</sup>C) and nitrogen (δ<sup>15</sup>N) in multiple food resources (leaves, coarse particulate organic matter, fine particulate organic matter, and periphyton) and aquatic insect assemblages. Our results indicate that fine particulate organic matter (FPOM) is the primary basal energy source for aquatic insects across all sites, regardless of elevation or level of canopy cover. The isotopic niche breadth of insects increased significantly with elevation, suggesting greater trophic diversity at higher altitudes. This pattern may reflect a broader spectrum of resource use and adaptability to varying environmental conditions. Additionally, we observed significant depletion in <sup>13</sup>C and <sup>15</sup>N values for vegetation, periphyton, and insects with increasing elevation. Our results provide insights into how basal resource quality changes along an elevation gradient and highlight the importance of small elevational gradients in shaping ecological processes. Further research is needed to explore the mechanisms driving isotopic variations along elevational gradients in tropical streams and to assess how the climate crisis affects food web dynamics in these ecosystems.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"46 ","pages":"Article e00429"},"PeriodicalIF":1.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145738985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-05DOI: 10.1016/j.fooweb.2025.e00428
Henrique Venâncio , Walter Santos de Araújo , Guilherme Ramos Demetrio , Wanessa Rejane de Almeida , Antonio Bruno Silva Farias , Aline Gonçalves , Jean Carlos Santos
Plant ontogeny modifies resource availability to herbivore communities, with drastic effects on gall-inducing insects preference during the host's development. In this study, we investigated the effects of plant ontogeny on the richness, abundance and interaction networks of gall communities. We used saplings, juveniles and mature individuals of the host plant Bauhinia brevipes Vogel (Fabaceae) and their associated galls as study models. Our results showed that gall-inducing insect richness was highest in mature plants, while abundance was higher in both sapling and mature plants. Moreover, gall community composition differed among the three developmental stages. These diversity parameters were positively associated with the number of leaves of the plants. The prevalence of gall-inducing insects on mature plants was also reflected in the network topology: galls were more linked, and significantly specialized, nested, and presented modules in mature plants. The interaction strength of one gall-inducing species increased in mature plants, while three gall-inducing insects increased with the number of leaves independently of the ontogenetic stage of plants, therefore refuting an ontogenetic succession in the system. We suggest that resource quantity and quality variation of host ontogeny act together to drive gall diversity and the network topology. Our study is one of the few to investigate the diversity of gall-inducing insect communities on host ontogeny, and pioneer to evaluate this effect on interaction networks. Overall, this study advances in the understanding of plant ontogeny in the interaction of gall-host systems, which may contribute to ecological aspects, including conservative efforts of gall-inducing insects.
{"title":"Is the older the better? Host plant ontogeny and resource availability drives gall-inducing insect diversity and network topology","authors":"Henrique Venâncio , Walter Santos de Araújo , Guilherme Ramos Demetrio , Wanessa Rejane de Almeida , Antonio Bruno Silva Farias , Aline Gonçalves , Jean Carlos Santos","doi":"10.1016/j.fooweb.2025.e00428","DOIUrl":"10.1016/j.fooweb.2025.e00428","url":null,"abstract":"<div><div>Plant ontogeny modifies resource availability to herbivore communities, with drastic effects on gall-inducing insects preference during the host's development. In this study, we investigated the effects of plant ontogeny on the richness, abundance and interaction networks of gall communities. We used saplings, juveniles and mature individuals of the host plant <em>Bauhinia brevipes</em> Vogel (Fabaceae) and their associated galls as study models. Our results showed that gall-inducing insect richness was highest in mature plants, while abundance was higher in both sapling and mature plants. Moreover, gall community composition differed among the three developmental stages. These diversity parameters were positively associated with the number of leaves of the plants. The prevalence of gall-inducing insects on mature plants was also reflected in the network topology: galls were more linked, and significantly specialized, nested, and presented modules in mature plants. The interaction strength of one gall-inducing species increased in mature plants, while three gall-inducing insects increased with the number of leaves independently of the ontogenetic stage of plants, therefore refuting an ontogenetic succession in the system. We suggest that resource quantity and quality variation of host ontogeny act together to drive gall diversity and the network topology. Our study is one of the few to investigate the diversity of gall-inducing insect communities on host ontogeny, and pioneer to evaluate this effect on interaction networks. Overall, this study advances in the understanding of plant ontogeny in the interaction of gall-host systems, which may contribute to ecological aspects, including conservative efforts of gall-inducing insects.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"45 ","pages":"Article e00428"},"PeriodicalIF":1.5,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-30DOI: 10.1016/j.fooweb.2025.e00427
Daylí Lladó-Cabrera , Sergio Aguíñiga-García , Laura Carreón-Palau , Felipe Galván-Magaña , Rogelio González-Armas , Arturo Tripp-Valdez
Predators like sharks play critical roles in marine and coastal ecosystems and shark population declines can have a variety of unexpected and disruptive effects on these ecosystems. To understand the food web associated with artisanal fishing of sharks, we analyzed the partitioning of food resources and the trophic retention of essential nutrients (e.g., fatty acids) in Sphyrna lewini, Squatina californica, and Rhizoprionodon longurio, three shark species with critically endangered, near threatened and vulnerable status, respectively, in the IUCN red list that coexist in a subtropical bay, the Bahía de La Paz, Baja California Sur, Mexico. We estimated short-term food partitioning using their diet analyzed by stomach contents. We evaluated the effect of stomach contents partitioning on the trophic niche, and profiles and concentration of essential fatty acids. The Prey-Specific Relative Importance Index showed that S. lewini has a more diverse diet. Although the three species of sharks share some prey items such as the Pacific mackerel Scomber japonicus, PERMANOVA analysis determined that the diet of these sharks is significantly different. There is low similitude of stomach content ranging between 2 and 5 %. R. longurio had the largest isotopic niche space obtained with Bayesian standard ellipse areas. Also, results of nicheROVER shows that R. longurio had higher mean probability of niche overlap with S. lewini (66 %), than with S. californica (46 %). Similarly, the greatest mean probability of niche overlap for S.californica was with R. longurio (88 %), while the mean probability of overlap in isotopic niche space was 40 % between the S. californica and S. lewini. Also, the high directional overlapping or low degree of partitioning of the isotopic niche between S. lewini and R. longurio was coincident with not significant difference in fatty acid profiles. Fatty acids profile similitude ranged between 76 and 89 %. These differences were found in the fatty acid profiles and concentrations. S. californica showed a higher separation from S. lewini and the lowest trophic retention of EPA and DHA. These observations suggest differences in metabolic requirements in S. californica or that with its ambush strategy, they obtain less food as they depend on finding ideal ambush sites.
像鲨鱼这样的捕食者在海洋和沿海生态系统中起着至关重要的作用，鲨鱼数量的下降会对这些生态系统产生各种意想不到的破坏性影响。为了了解与鲨鱼手工捕捞相关的食物网，我们分析了在墨西哥下加利福尼亚州Bahía de La Paz的世界自然保护联盟（IUCN）红色名录中共存的三种鲨鱼的食物资源分配和必需营养素（如脂肪酸）的营养保留。这三种鲨鱼分别处于极度濒危、近危和脆弱状态。我们通过胃内容物分析他们的饮食来估计短期食物分配。我们评估了胃内容物分配对营养生态位的影响，以及必需脂肪酸的分布和浓度。猎物特异性相对重要性指数表明，lewini s具有更多样化的饮食。尽管这三种鲨鱼有一些共同的猎物，比如太平洋鲭鱼（Scomber japonicus），但PERMANOVA的分析表明，这三种鲨鱼的饮食有很大的不同。胃内容物相似度低，在2% ~ 5%之间。用贝叶斯标准椭圆面积得到的同位素生态位空间最大。此外，nicheROVER结果表明，longurio与S. lewini的平均生态位重叠概率（66%）高于与S. california的平均生态位重叠概率（46%）。同样地，加利福尼亚加利福尼亚加利福尼亚加利福尼亚与长谷鼠的生态位重叠的平均概率最大（88%），而加利福尼亚加利福尼亚与lewini在同位素生态位空间重叠的平均概率为40%。此外，lewini和R. longurio同位素生态位的高度定向重叠或低程度划分与脂肪酸谱差异不显著一致。脂肪酸谱相似度在76%到89%之间。这些差异是在脂肪酸谱和浓度上发现的。从美国lewini californica显示更高的分离和EPA和DHA的最低营养保留。这些观察结果表明代谢需求的差异在美国californica或者伏击策略,他们获得较少的食物取决于找到理想的伏击地点。
{"title":"Food partitioning, trophic niche, and fatty acid composition and trophic retention in co-existing threatened sharks with different feeding strategies","authors":"Daylí Lladó-Cabrera , Sergio Aguíñiga-García , Laura Carreón-Palau , Felipe Galván-Magaña , Rogelio González-Armas , Arturo Tripp-Valdez","doi":"10.1016/j.fooweb.2025.e00427","DOIUrl":"10.1016/j.fooweb.2025.e00427","url":null,"abstract":"<div><div>Predators like sharks play critical roles in marine and coastal ecosystems and shark population declines can have a variety of unexpected and disruptive effects on these ecosystems. To understand the food web associated with artisanal fishing of sharks, we analyzed the partitioning of food resources and the trophic retention of essential nutrients (e.g., fatty acids) in <em>Sphyrna lewini</em>, <em>Squatina californica</em>, and <em>Rhizoprionodon longurio</em>, three shark species with critically endangered, near threatened and vulnerable status, respectively, in the IUCN red list that coexist in a subtropical bay, the Bahía de La Paz, Baja California Sur, Mexico. We estimated short-term food partitioning using their diet analyzed by stomach contents. We evaluated the effect of stomach contents partitioning on the trophic niche, and profiles and concentration of essential fatty acids. The Prey-Specific Relative Importance Index showed that <em>S. lewini</em> has a more diverse diet. Although the three species of sharks share some prey items such as the Pacific mackerel <em>Scomber japonicus</em>, PERMANOVA analysis determined that the diet of these sharks is significantly different. There is low similitude of stomach content ranging between 2 and 5 %. <em>R. longurio</em> had the largest isotopic niche space obtained with Bayesian standard ellipse areas. Also, results of nicheROVER shows that <em>R. longurio</em> had higher mean probability of niche overlap with <em>S. lewini</em> (66 %), than with <em>S. californica</em> (46 %). Similarly, the greatest mean probability of niche overlap for <em>S.californica</em> was with <em>R. longurio</em> (88 %), while the mean probability of overlap in isotopic niche space was 40 % between the <em>S. californica</em> and <em>S. lewini.</em> Also, the high directional overlapping or low degree of partitioning of the isotopic niche between <em>S. lewini</em> and <em>R. longurio</em> was coincident with not significant difference in fatty acid profiles. Fatty acids profile similitude ranged between 76 and 89 %. These differences were found in the fatty acid profiles and concentrations<em>. S. californica</em> showed a higher separation from <em>S. lewini</em> and the lowest trophic retention of EPA and DHA. These observations suggest differences in metabolic requirements in <em>S. californica</em> or that with its ambush strategy, they obtain less food as they depend on finding ideal ambush sites.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"45 ","pages":"Article e00427"},"PeriodicalIF":1.5,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145466844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.fooweb.2025.e00426
Guillermo Lezama-Balderas , Ana Leite-Vital , Ximena González-Galindo , David Rendón-Sauz , Evelyn Bárcenas , Laura Zapiain , Jacqueline Romero , Robert Carrión , Adriana Del Villar , Heysa Sigala-Valdez , Alfredo Ramírez-Hernández , Fredy Alvarado
Flower crops are valuable in promoting the provision of resources for flower visitors and pollinators in anthropized landscapes. In Mexico, the traditional “Flower of the Dead” (Tagetes erecta, marigold or “Cempasúchil” in Spanish) is a plant of great biocultural value. However, despite its importance, we know very little about the role of urban temporary crop fields of “Cempasúchil” as reservoirs of biodiversity. Here, we systematically sampled adult butterflies in 6 urban “Cempasúchil” crop fields. Our observations revealed that 39 species of diurnal butterflies are flower visitors to “Cempasúchil” crop fields. Remarkably, 6 of the species recorded undertake autumn migrations, highlighting the importance that “Cempasúchil” crop fields may represent an important nectar resource for migratory species in urban areas. We also recorded species reported to be in serious population decline actively feeding on “Cempasúchil” flowers. Although the expansion of agricultural and urban areas has been considered an important driver of butterfly species decline and local extinction, our results emphasize the importance of “Cempasúchil” crop fields in agricultural and urban landscapes for the maintenance of butterfly biodiversity in an arid city. Thus, we suggest that urban conservation efforts could focus on the creation of “Cempasúchil” plots that promote biodiversity connectivity and ecosystem service provision in human-dominated-landscapes.
{"title":"Cultivating marigolds: From ancestral tradition and heritage to importance for butterfly conservation in a Mexican semi-arid city","authors":"Guillermo Lezama-Balderas , Ana Leite-Vital , Ximena González-Galindo , David Rendón-Sauz , Evelyn Bárcenas , Laura Zapiain , Jacqueline Romero , Robert Carrión , Adriana Del Villar , Heysa Sigala-Valdez , Alfredo Ramírez-Hernández , Fredy Alvarado","doi":"10.1016/j.fooweb.2025.e00426","DOIUrl":"10.1016/j.fooweb.2025.e00426","url":null,"abstract":"<div><div>Flower crops are valuable in promoting the provision of resources for flower visitors and pollinators in anthropized landscapes. In Mexico, the traditional “Flower of the Dead” (<em>Tagetes erecta</em>, marigold or “Cempasúchil” in Spanish) is a plant of great biocultural value. However, despite its importance, we know very little about the role of urban temporary crop fields of “Cempasúchil” as reservoirs of biodiversity. Here, we systematically sampled adult butterflies in 6 urban “Cempasúchil” crop fields. Our observations revealed that 39 species of diurnal butterflies are flower visitors to “Cempasúchil” crop fields. Remarkably, 6 of the species recorded undertake autumn migrations, highlighting the importance that “Cempasúchil” crop fields may represent an important nectar resource for migratory species in urban areas. We also recorded species reported to be in serious population decline actively feeding on “Cempasúchil” flowers. Although the expansion of agricultural and urban areas has been considered an important driver of butterfly species decline and local extinction, our results emphasize the importance of “Cempasúchil” crop fields in agricultural and urban landscapes for the maintenance of butterfly biodiversity in an arid city. Thus, we suggest that urban conservation efforts could focus on the creation of “Cempasúchil” plots that promote biodiversity connectivity and ecosystem service provision in human-dominated-landscapes.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"45 ","pages":"Article e00426"},"PeriodicalIF":1.5,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145322337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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