Echolocating mammals comprise an evolutionarily and functionally distinct group of often cryptic species that navigate using ultrasound, of which many terrestrial representatives are nocturnal. We show that, compared to non-echolocators, these species are disproportionately represented in data-deficient or unevaluated IUCN categories, due to fewer population studies. This pattern is associated with ecological and socioeconomic correlates of detectability and research effort, including occurrence in less accessible habitats (e.g., caves and open ocean), smaller population sizes, restricted areas of occupancy, and lower national economic prosperity. We recommend that, given their evolutionary and functional distinctiveness, high taxonomic richness (particularly in bats), and important ecosystem functions, echolocators warrant greater IUCN assessment and elevated conservation priority, especially considering the ongoing threats that they face.

Underwater noise from human activities is an increasing concern due to its potential ecological impacts. While knowledge on its effects on aquatic species is growing, responses of juvenile invertebrates remain poorly understood. This study investigated behavioral, cellular, and molecular responses to noise (1-20kHz linear sweep) in juvenile Procambarus clarkii (Girard, 1852). Behavioral parameters (including movement, interactions, feeding, and tail flips) were recorded using overhead video and analyzed with BORIS software. Cellular assays measured esterase, alkaline phosphatase, glucose, total protein (TP), peroxidase, superoxide dismutase (SOD), and cytotoxicity. Additionally, gene expression of crustin, prophenoloxidase (proPO), Heat shock protein 70 (HSP70), Heat shock protein 90 (HSP90), caspase, SOD and catalase (CAT) was assessed via real-time PCR. Specimens exposed to underwater noise exhibited increased interactions and feeding, but no significant changes in movement were observed. Results of cellular analysis revealed elevated protein content, hydrolase, and antioxidant activity, while glucose and cytotoxicity levels decreased. Molecular analyses showed upregulation of immune and stress-related genes (crustin, proPO, HSP70, HSP90, and caspase) and downregulation of SOD and CAT, indicating potential oxidative stress. These findings suggest that even early life stages of invertebrates are sensitive to underwater noise disturbance, affecting the specimens at multiple interconnected levels.

This study aimed to investigate whether the attractiveness of female dragline silk sex pheromones in the wolf spider Pardosa pseudoannulata varies with female age, and to identify the key chemical compounds responsible for male attraction. We conducted integrated behavioral, chemical, and electrophysiological analyses. Dragline silk was collected from females of three age groups (young, middle-aged, and old). Male courtship behaviors were assessed in response to silk exposure. Silk extracts were analyzed using gas chromatography coupled with electroantennographic detection and mass spectrometry. Candidate pheromone compounds were further evaluated via electroantennography and Y-tube olfactometer assays to confirm their behavioral relevance. Male spiders exhibited significantly stronger courtship responses, shorter latency, higher palpal drumming, and increased leg vibration, toward silk from young and middle-aged females compared to older females. Three compounds-oleic acid, n-heptacosane, and squalene-were consistently identified as key pheromone components across age groups. Their electrophysiological activity was concentration and solvent dependent, while behavioral attraction was confirmed under tested conditions. In behavioral assays, synthetic versions of these compounds at 0.01µg/µL in mineral oil significantly attracted males, confirming their role as sex pheromone components. The findings demonstrate that female age significantly influences the chemical composition and attractiveness of dragline silk pheromones in P. pseudoannulata. Younger females produce more attractive pheromone blends, guiding male mate preference. The identification of oleic acid, n-heptacosane, and squalene as bioactive compounds provides new insights into spider chemical ecology and supports potential applications in eco-friendly pest management strategies.

Seed traits play a pivotal role in shaping rodent-mediated seed dispersal, a key process driving forest regeneration. However, disentangling the independent and interactive effects of physical (coat thickness), nutritional, and chemical (tannin) traits remains challenging due to their natural covariation. Using artificial seeds in enclosures, we quantified how these traits influence foraging decisions by Leopoldamys edwardsi, a dominant scatter-hoarding rodent in subtropical forests. Our results revealed a hierarchical order of trait importance: nutrient content > tannin content > coat thickness. High-nutrient seeds were preferentially consumed, while moderately nutrient-rich seeds (50% peanut powder) were most frequently scatter-hoarded, balancing immediate energy gain and long-term storage. Tannins exerted a dual effect: low concentrations (0.5%) enhanced consumption, likely due to reduced microbial decay, whereas high concentrations (7%) deterred both consumption and hoarding by impairing digestibility. Coat thickness had weaker effects but interacted with nutrients, as thin-coated, high-nutrient seeds were favored for both consumption and hoarding. Interactive effects highlighted a "benefit-first" decision framework, where rodents prioritize energy gain (nutrients), then modulate behavior to preserve benefits (tannins aiding storage), and finally account for handling costs (coat thickness). These findings illuminate coevolutionary dynamics between rodents and seeds, emphasizing how trait combinations shape mutualistic interactions critical for forest dynamics. Our study provides a mechanistic basis for predicting how shifts in seed traits may disrupt these interactions, with implications for ecosystem management.

Members of the Onchocercidae family are parasites that infect a wide range of tetrapods, including wild birds and other animals. In Colombia, studies on avian blood parasites have diagnosed infections with microfilariae in several species using light microscopy. However, no morphological or molecular analyses of these nematodes have been conducted to date. The present study examined samples from 3820 wild birds with material deposited in the biological collection of the Host-Parasite Relationship Study Group since 1999. Of these individuals, 142 (3.7%) were infected with microfilaria and were analyzed using morphological and morphometric measurements. Additionally, 55 samples with blood or tissue preserved in ethanol were analyzed for sequencing of nuclear marker 18S rDNA and mitochondrial markers 12S rDNA and COI. Morphological analyses showed infection by at least one of 13 designed morphotypes of microfilariae. Twenty-nine sequences were obtained (10 of COI, 6 of 12S, and 13 of 18S), corresponding to 21 molecular lineages associated with Onchocercidae. These sequences were associated with the subfamilies Lemdaninae and Splendidofilariinae, the genera Aproctella Cram, 1931, Splendidofilaria Skrjabin, 1923, and Eufilaria Seurat, 1921, and other sequences did not cluster within any genus for which sequences were available for a particular molecular marker. These findings establish the first framework of morphological and molecular diversity of avian Onchocercidae in the megadiverse Neotropical country Colombia, expanding the known distribution of several genera and highlighting the need for further sampling of adult filariids to refine taxonomic resolution.

Precise quantification of the parasitic load during infections is necessary for a deep understanding of parasite-host interactions. Haemosporidians, an order of intracellular blood parasites, including agents of avian malaria and their closer relatives, have two organelles, remnants of endosymbiosis: the mitochondrion and the apicoplast, which have their own extranuclear genomes (nucleoids). While the number of organelles per parasitic cell appears to be stable, the number of their nucleoids is not, but the dynamics and factors affecting them still remain to be elucidated. We used a set of 71 blood samples of migratory birds infected by haemosporidian parasites to quantify relative DNA quantities of these two organelles through real-time quantitative PCR (qPCR). We investigated the congruence of these two parameters with the microscopically detected number of parasites, for all samples measured and for the subset of those with moderate to high parasitemia. We found that apicoplast DNA content was a better predictor for intermediate infection intensities, while mitochondrial DNA content was a better predictor for acute infections. This difference may result from the regulation of parasite intra- and inter-organellar genomic content throughout the infection stages in vertebrate hosts. Our work contributes to the methods for quantification of blood parasites in wildlife and to the understanding of their development and conservation-relevant consequences for the avian hosts.

Avian blood parasites of the genera Plasmodium, Haemoproteus, and Leucocytozoon are typically identified through Sanger sequencing of a partial cytochrome b fragment, the MalAvi barcoding region. This approach limits the detection of mixed infections and the relative frequencies of co-infecting parasites. In contrast, next-generation sequencing (NGS) can resolve these problems but has been underused for haemosporidian lineage identification in samples from the wild. We used an improved PCR protocol and sequencing with Illumina MiSeq to determine haemosporidian assemblages in wild birds captured at a migration stopover site in Bulgaria, Europe. From 406 samples obtained from 52 bird species, we detected 81 haemosporidian lineages in 131 infected samples from 32 species (32% prevalence). On average, individuals were infected with 2.4 lineages, with 59 birds infected by a single lineage, and 21 birds infected with 5-9 lineages. A subset of samples was Illumina- and Sanger-sequenced in parallel, finding mixed infections in 72 samples and 8× higher detection rate of mixed and co-infections through high-throughput sequencing. Both methods identified the same dominant (co-infecting) lineage (91%). Metabarcoding identified common mixed infections of sister lineage groups ("sisterhoods") known for prevalent lineages and morphospecies, including Plasmodium relictum p_SGS1, Haemoproteus motacillae h_YWT2, and Haemoproteus parabelopolskyi h_SYAT01. Some other lineages appeared consistently more dominant. Our study shows that in some host communities, metabarcoding can reveal a great diversity of mixed infections. This opens new horizons to the study of assemblages of haemosporidian parasites, their interactions within individual hosts, and co-evolution with other members of the blood microbiome and the hosts.

The adaptive evolution of Canidae mitochondrial genomes and their mechanistic association with ecological strategies have long been constrained by insufficient cross-lineage integration and unresolved multidimensional interaction networks. Here, complete mitochondrial genomes from all extant canid species (including 11 newly assembled genomes) were analyzed, revealing highly conserved gene arrangements and lineage-specific codon usage patterns. High-altitude species exhibited atypical initiation codons for ND4L, while boreal species exhibited significant termination codon shifts, and polar specialists had distinct codon optimization profiles. Positive selection analyses identified strong selective pressures on arginine- and leucine-encoding sites, with core oxidative phosphorylation genes demonstrating accelerated adaptive evolution in large-bodied canids and specialized predatory lineages. Phylogenomic reconstructions revealed consistency in South American Lycalopex radiation timing with regional orogenic events, while also linking Canis diversification to grassland biome expansion. Further, statistical models confirmed robust correlations between mitochondrial evolutionary rates and both body mass and predatory ecology, wherein body size increases drive metabolic optimization through lineage-specific selection on energy-related genes. Based on these observations, a "functional constraint-geological driver-body size adaptation" tripartite framework is proposed that highlights how mitochondrial genomes maintain metabolic plasticity through mutation-selection equilibrium, how geological events trigger lineage divergence, and how body size-predation strategies shape modular gene evolution. Consequently, this study establishes a novel paradigm for understanding genome-environment interactions in terrestrial carnivore adaptations.