Current Zoology最新文献

Mate choice plays a pivotal role in wildlife reproduction and population sustainability. The assessment of sexual displays in noise poses a common challenge for wildlife. Multimodal signals are hypothesized to be favored since they improve the accuracy of signal detection and discrimination in noise. We verified whether female treefrogs exhibit a heightened reliance on visual cues when acoustic cues are drowned out by the noise and whether increased call complexity can compensate for the attractiveness differences between unimodal and multimodal signals. Our results demonstrated that female treefrogs prefer longer courtship signals in the absence of noise. Meanwhile, increasing call complexity effectively mitigated the attractiveness difference between acoustic and visual/multimodal signals. However, female treefrogs did not shift their reliance to visual signals when masked by noise. Noise prolonged the duration required for females to make a mate choice in most cases and reduced female preferences for attractive signals regardless of whether the mating scene was unimodal or multimodal, which lends further the hypothesis of cross-sensory interference. We examined how female treefrogs weigh unimodal and multimodal courtship cues in the absence and presence of noise and offered distinct perspectives on the interplay of multi-sensory sexual displays in noise. This study enhanced our comprehension of noise interference in mating choice and established a novel, comprehensive scientific foundation for the prevention and control of multimodal sensory pollution.

Sponges (Porifera) are traditionally considered to lack defined body axes and regional specialization. Understanding whether sponges exhibit preferential growth regions and axial patterning is essential for elucidating the evolution of metazoan body plans. Here, we compared two body regions of the repent morph of Cladocroce caelum (Demospongiae): the proximal region, containing fully developed aquiferous system modules, and the distal region, hypothesized as the primary growth region. Our findings show that specimens predominantly grow from the distal region, where archaeocytes constitute the main cell type (mean 65.3%), whereas the proximal region features aquiferous system modules primarily composed of choanocytes (47%). To further explore molecular differences, we assembled a de novo reference transcriptome for C. caelum, recovering 99% of universal eukaryotic orthologous genes and 94% of metazoan orthologs. RNA-seq analysis revealed the expression of genes associated with the germline, stem cells, and developmental signaling pathways in both regions. However, we identified 11,421 differentially expressed genes (3,506 upregulated in the proximal region and 7,925 in the distal region). Notably, genes involved in the WNT, TGF-β, and MAPK pathways-key regulators of development and cell proliferation-were upregulated in the distal region. These findings provide morphological and molecular evidence of regional specialization in C. caelum, supporting the existence of a preferential growth region at the distal end. Our results suggest that despite the unique organization of the sponge body plan, some poriferans may possess specialized growth regions, akin to those in other metazoans.

Major geoclimatic events trigger clade divergence, shaping diversification patterns. However, the influence of historical geoclimatic events on the diversification of subsurface biota remains poorly understood. This study investigates the phylogeny and evolutionary history of under-recognized hypogean fishes in the Nemacheilidae family (HFN) in southwestern China, using mitogenome and nuclear gene sequencing. Our phylogeny supports the current genus-level classification but reveals conflicts between mitochondrial and nuclear gene topologies, suggesting past hybridization events. The ancestor of the HFN originated in eastern China-Korean Peninsula-Japanese Islands, north of northwest China-Mongolian Plateau, the Qinghai-Xizang (Tibetan) Plateau-Hengduan Mountains during the late Eocene (~36 million years ago [Mya]) and early Miocene (~16 Mya), and dispersed twice into the karst region of southwestern China. An ancient radiation event occurred from 22.44 Mya to 12.25 Mya. In situ diversification is the major speciation event, originating around 30 Mya and increasing sharply at ~11 Ma, with 3 peaks at ~7 Mya, ~3 Mya, and 1 Mya, and 2 valleys at ~5 Mya and ~2 Mya. Ancestral state reconstruction suggests at least 4 independent origins for the colorless, eye-blind, and troglobitic species morphs, as opposed to 2 events for the caudal adipose keel, and that these traits have undergone multiple reversals. These results highlight the role of geological processes and climatic events in the evolution of hypogean fishes and provide insights for conservation efforts, particularly in specialized cave habitats.

In certain North Atlantic rocky shores, 2 chromosomal lineages of Nucella lapillus have been observed at different extremes of an environmental gradient. Here, we have determined the presence of this chromosomal polymorphism, resulting from Robertsonian translocations, in populations of the Iberian Peninsula spanning a similar gradient. Interestingly, we have found monomorphic populations (2n = 26) across the gradient while we only found polymorphic populations (2n = 27-36) in certain exposed microhabitats, and never both types of populations together. These chromosomal lineages differ morphologically and genetically in a manner that can be successfully discriminated, based on their morphology (95% of success) and molecular variation (99.9% of success), in the studied set of samples, and so considering these data this could potentially represent isolated evolutionary lineages or taxa. This situation is discussed in relation to the data available in previous studies in this and other geographical areas for this species. The new findings do not solve the problem of the Robertsonian polymorphism known to exist in this species, but it could perhaps suggest a new approach to solve it, suggesting a wide geographical comparison between the 2 taxa to confirm if they represent evolutionary isolated lineages or maintain a certain degree of hybridization.

Numerous bird species have adapted to rapid urbanization, navigating challenges introduced by novel stressors. While prior research has explored how urban exploiters adjust their physiology relative to their rural counterparts during breeding season, the modulation of multiple physiological markers outside of reproduction, and the maintenance of sex-specific differences, remain less understood. Using an urban exploiter, the Eurasian tree sparrow (ETS; Passer montanus), we investigated how both sexes of urban and rural populations modulate twenty-two physiological markers of nutrition, body condition, oxidative stress, and antioxidative responses during pre-breeding stage. Our results showed that urban ETSs displayed distinct glucolipid metabolism compared to rural ETSs, characterized by higher levels of free fatty acids, β-hydroxybutyric acid, high-density lipoprotein (HDL), and total cholesterol, alongside lower levels of triglycerides, glucose (Glu), and fat content (FC). No significant differences were observed in other physiological markers. Additionally, both sexes of urban ETSs exhibited similar profiles across these markers, unlike rural populations where females showed higher Glu and total protein levels and lower HDL and FC levels than males. Our findings suggest that birds adjust their nutritional physiological markers in response to urbanization, likely due to dietary differences between urban and rural environments. Furthermore, sex differences in physiological markers of nutrition, body condition, oxidative stress, and antioxidant responses appear to diminish in urban settings.

Social foraging is a collective solution to the challenge of catching prey. A remarkable example involving different predator species with complementary hunting skills is Lahille's bottlenose dolphins, Tursiops truncatus gephyreus foraging with net-casting human fishers to catch migratory mullet, Mugil liza. It remains unknown, however, to what extent dolphins coordinate their own actions when foraging with humans, and how intraspecific coordination impacts interspecific foraging success. Using drone-based tracking, we quantified dolphin group surfacing behaviors (diving synchrony, proximity, and heading angles between individuals) and tested the repeatability of these behavioral metrics across independent human-dolphin cooperative foraging interactions. We then quantified how the variance and consistency in these behaviors influenced the likelihood of fishers catching mullet. We found repeatable patterns in dolphin group proximity and heading angles across cooperative foraging interactions with fishers, and that fishers were more successful at catching mullet when dolphins approached them along different trajectories with consistent diving synchrony. These findings suggest that groups of dolphins can be, to some extent, coordinated when fishing with humans, thereby influencing the collective outcome of this cooperative foraging tactic. We consider hypotheses for the underlying mechanisms of synchrony and coordination within groups of dolphins and highlight solutions for overcoming the inherent challenges associated with quantifying collective foraging dynamics in natural settings.

Animal species exhibit a wide range of coloration and patterns, which are under strong selection and often linked to individual quality, influencing mate choice, recognition, signaling, and interspecific interactions such as predator avoidance. In amphibians, coloration can vary based on individual traits as well as environmental conditions, including the coloration of their environment. In this study, we described the dorsal coloration (body coloration reticulated by dark patches) in 676 Western spadefoot toads (Pelobates cultripes) from the French Atlantic coast, comparing color variations across different substrates. In addition, we assessed color change in 18 toads transferred between bright and dark substrates. We demonstrated that the dorsal coloration varies based on capture locations (beach vs. inland) and associated substrate types (bright vs. dark), suggesting background color matching. We showed more pronounced effects in females, which might reflect varying predation risks. Experimentally, we showed that individuals can rapidly adjust their coloration to match the substrate within 24 h. Rapid color changes in response to substrate type indicate significant pigmentation plasticity. Bright individuals from sandy substrates showed less dorsal background (body) color change than dark inland individuals, while patch coloration responded differently depending on the substrate of origin. These findings highlight the complex interactions between substrate type, sex, and pigmentation plasticity. These interactions have potential costs and benefits, which might be linked to melanin production, which warrant further investigation.

Different habitat types exert particular challenges to ecological performance, ultimately having a strong influence on the evolution of morphology. Although it is well known that external morphology can evolve under the selective pressure of habitat structure, the evolutionary response of internal morphological traits remains vastly unexplored. Here, we test for morphological divergence between arenicolous and nonarenicolous species in a clade of tropidurid lizards, considering external morphological proportions and limb muscle dimensions. We found that arenicolous species seem to have evolved internal and external morphological adaptations that separate them from other habitat specialists. Moreover, comparative analyses suggested that the traits that differed the most between arenicolous and nonarenicolous lizards might have evolved divergently towards different optima. Additionally, the axis of higher morphological divergence between arenicolous and nonarenicolous species represented an important proportion of the morphological diversity within our sample, indicating that the hypothetical adaptive divergence of internal and external traits has contributed significantly to phenotypic diversity. Our results show that evolutionary associations between morphology and habitat use can be detected on both external body proportions and muscle morphology. Moreover, they highlight the emergent importance of internal anatomical traits in ecomorphological studies, especially when such traits are directly involved in determining functional performance.

Variation in the vocal behavior of nonhuman vertebrates includes graded transitions and more dramatic changes. Wapiti males produce a reproductive bugle that has a fundamental frequency that surpasses 2,000 Hz with evidence of biphonation and other nonlinear phenomena. Here, we analyze the acoustic structure of captive wapiti vocalizations to compare the male bugle with 3 categories of distress vocalizations: neonate distress (capture) calls, calf isolation calls, and adult female isolation calls. These 4 high-arousal call categories serve a common general function in recruiting conspecifics but occur in different behavioral contexts (capture, isolation, reproduction). Our goal was to distinguish characteristics that vary in graded steps that may correspond to an animal's age or size from characteristics that are unique to the bugle. Characteristics of the high and loud fundamental (G0) varied in an age/size-graded manner with a decrease in minimum G0, an increase in the maximum and range of G0, with no evidence of sex differences. The nonlinear phenomena of deterministic chaos, biphonation, and frequency jumps were present in all 4 call categories and became more common from the distress vocalizations of neonates to calves to adult females to the male bugle. Two temporal characteristics sharply distinguished the bugle from the 3 categories of distress vocalizations: these included a prolonged call duration and a maximum G0 that occurred much later in the call for the bugle than for distress vocalizations. Our results suggest that distress vocalizations of different age groups and the reproductive bugle of wapiti share a high G0, with age/size-graded changes in G0 and nonlinear phenomena, but differ sharply in temporal characteristics.

Little Terns Sternula albifrons are estuarine birds extensively using increasingly urbanized coastal areas. Given the increased exposure of these ecosystems to anthropogenic activities, it is crucial to study the ecology of this species and interactions with human stressors to establish management measures. We collected regurgitates (n = 182) and blood samples (n = 48) to study Little Terns' diet, health condition and isotopic niche, and individually tracked breeding adults (n = 9, during 2021 and 2022) at 2 sandy beaches 21 km apart and located within Ria Formosa Natural Park, Algarve, Portugal. Although both areas are adjacent to foraging coastal marine areas and an estuarine lagoon system with saltpans, they differ in human disturbance. We also compared breeding success and adult health measures between these 2 colonies. The main prey for both populations were Sand Smelts Atherina spp. and Gobies Pomatoschistus spp., and no differences in δ ¹³C and δ ¹⁵N stable isotopic values between colonies were found. Tracking data revealed that individuals foraged in the surroundings of their breeding colonies. Entrance Channels and Ocean were the most frequently used habitats for foraging by individuals from the less disturbed colony. Adults from the more disturbed colony foraged mostly in Entrance Channels. Overall, all individuals tended to forage during daytime. There were no differences in health measures of individuals between colonies, though breeding success at the most disturbed colony was comparably lower. It is important to protect both breeding areas and adjacent foraging habitats for Little Terns, particularly given the expected increasing pressure from human activities on coastal areas worldwide.