Wildfire ash impacts the early development of the sea urchin Paracentrotus lividus.

Ocean warming is altering abiotic environments and biotic interactions experienced by marine organisms, where sensitive early developmental windows occur in biologically complex seawater communities. The impact of these interactions on developmental processes and fitness in hosts is not well understood, but likely contingent on the establishment of a host-associated microbiome. Here, we hypothesize that temperature and microbial exposure during embryogenesis influence larval microbiome assembly and host morphology. Strongylocentrotus purpuratus embryos were raised in low microbial richness (LMR) or high microbial richness (HMR) seawater at ambient (14 °C) or elevated (18 °C) temperature, then collected at 2, 4, and 6 days post-fertilization (dpf) following multiple feedings. Higher microbial diversity was observed in larvae that developed in HMR seawater when compared to LMR. Differences in relative abundances of dominant microbial families between seawater and larvae suggest some degree of host selectivity in microbiome assembly. Temperature did not strongly alter microbiome composition, but both temperature and microbial condition led to differences in larval morphology by 6 dpf, potentially due to enrichment of microbes with chemoheterotrophic functions. By linking how temperature and microbial communities interact with host development, we contribute novel insights into how early-life environmental conditions impact holobiont formation and morphology.

Fanniidae (Diptera) of forensic importance, with an identification key for third instar larvae of European species.

ABSTRACTSuccessful parasite proliferation depends on eco‐evolutionarily stable host–parasite relationships, which may be disrupted by the introduction of non‐native alternative hosts, particularly in the case of the generalist parasites adapted to multiple host species. Here, we experimentally analysed how the addition of a non‐native alternative host affects the infection success of a larval generalist trematode, Diplostomum pseudospathaceum. We assessed parasite abundance, the proportion of successfully established metacercariae, and host‐dependent parasite growth in the principal (Abramis brama), the native alternative (Rutilus rutilus), and the non‐native alternative (Lepomis gibbosus) fish intermediate hosts. Across all experiments, A. brama showed the highest susceptibility to D. pseudospathaceum, with significantly lower abundances in both alternative hosts. This supports the view that evolutionary compatibility and host–parasite coadaptation in generalists play a more decisive role in shaping infection patterns than ecological factors such as host abundance or encounter rates. Multi‐host experiments revealed a significant reduction in the proportion of successfully established metacercariae, particularly in combinations of native hosts with non‐native L. gibbosus, indicating a dilution effect. Moreover, L. gibbosus exhibited a pronounced response to infection, developing stronger cataract than native hosts. Cataract formation was also more likely at lower infection intensities, indicating a lower threshold for pathology in the non‐native host without a shared evolutionary history with the parasite, compared to long‐term coexisting hosts. Metacercariae differed subtly yet significantly in size and organ dimensions among host species, demonstrating that host identity can affect larval morphology. Overall, our results demonstrate that the presence of alternative hosts, especially the non‐native ones, can reduce parasite transmission through encounter dilution and suboptimal infection, even when those hosts are susceptible, confirming that dilution effects are not restricted to non‐competent or resistant hosts.

The widespread use of pesticides has heightened the risk of toxic effects on nontarget species. Among these compounds, the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D), one of the most widely used herbicides worldwide, raises concerns about its potential environmental impacts and the exposure of nontarget organisms. This study therefore investigated the effects of the active ingredient 2,4-D on the larval physiology, morphology, and oxidative and metabolic responses of the microcrustacean Artemia franciscana. For the developmental assays, A. franciscana nauplii were exposed to different concentrations of 2,4-D (50-500 mg·L-1) for 24 and 48 hr. Based on these assays, the no observed effect concentration (100 mg·L-1), half-maximal effect concentration (EC50; 365.1 mg·L-1), and the highest tested concentration (500 mg·L-1) were selected to evaluate morphological effects after 24 hr of exposure, including body length, eye diameter, and the number of thoracopods. Apoptosis in nauplii was assessed using acridine orange staining. Enzymatic responses related to oxidative stress (catalase and glutathione peroxidase [GPx]) and energy metabolism (lactate dehydrogenase [LDH]) were also assessed after 24 hr. The four highest concentrations of 2,4-D (200, 300, 400, and 500 mg·L-1) decreased the mobility of the nauplii at both exposure times. Exposure to the EC50 and the highest tested concentration of 2,4-D resulted in decreases in body length, eye diameter, and the number of thoracopods in the nauplii. Acridine orange staining revealed apoptosis after 24 hr of exposure at the EC50 but not at sublethal concentrations. Additionally, exposure to sublethal concentrations of 2,4-D (0.1 to 100 µg·L-1) decreased LDH activity and increased GPx activity after 24 hr. This study demonstrated that only 2,4-D concentrations significantly higher than those typically found in aquatic environments adversely affected the mobility, morphology, and metabolic activity of A. franciscana nauplii. Further research is needed to assess the lethal and sublethal effects of different 2,4-D formulations on nontarget organisms.

Morphology of mature larvae and life cycle of Semijulistus spectabilis (Lewis, 1895) (Coleoptera: Rhadalidae) are described here for the first time. A comparative analysis of the larval morphology of S. spectabilis and other rhadalid species revealed that the larvae of S. spectabilis lacked the typical characteristics observed in other rhadalid species, i.e., pigmented and sclerotized (whole or partial) thoracic tergites, abdominal tergite IX bearing a pair of urogomphi or a pigmented sclerite. Furthermore, S. spectabilis exhibits distinctive characteristics that deviate markedly from the fundamental larval morphology typical of the melyrid lineage, including a small head capsule, a slender body, and an exceptionally thin cuticle. Although the total duration of the larval stage was long, there were fewer larval molts until they prepupated than observed in other members of the melyrid lineage.

A sensitive sentinel: Chironomus xanthus as a bioindicator of freshwater sediment quality in Southern Latin America.

Variation in thermal plasticity of larval morphology among crested newt species and their reciprocal hybrids (Salamandridae: Triturus).

How morphological diversity arises from variations in biomechanical processes remains an open question. Although forces shape tissues, how force-generating systems differ across species to create diverse forms is unclear. Here, we combine comparative morphogenesis and active matter theory across six cnidarian species spanning 500 million years of divergence to identify the mechanical basis of larval shape diversity. We define species-specific configurations of mechanical modules-termed mechanotypes-that quantitatively predict larval shapes across taxa. We find that shape elongation is a simple trait at the mesoscale level, as its variation depends on one mechanical module, whereas shape polarity is a complex trait dependent on several modules. Perturbations mimicking interspecies regulatory differences reshape these modules, reprogramming larval morphology into forms resembling sister species. By establishing a mesoscale mechanical framework for cross-species comparison, this work reveals how variations in a limited set of tissue-scale parameters generate morphological diversity.

This study aims to evaluate the toxicity effects of dexamethasone on survival, hatching, cardiometabolic function, and the emergence of malformations in zebrafish larvae (Danio rerio), a vertebrate model organism. The study was conducted during the embryonic to early larval phase (0 – 96 hpf) using an in vivo experimental design with complete randomization, following the Zebrafish Embryo Toxicity Test (ZFET) approach, in accordance with OECD 236 guidelines. Zebrafish embryos were exposed to varying concentrations of dexamethasone (0.5,1, 3, and 7 ppm). The parameters observed included survival rate, hatching rate, cardiometabolic function, and changes in larval morphology. Data were analyzed using normality and homogeneity tests, followed by One-Way ANOVA with LSD post hoc tests and Two-Way ANOVA. The results showed that exposure to dexamethasone did not cause lethal toxicity in zebrafish larvae up to 96 hpf (P = 0.949), but significantly inhibited hatching at 48 hpf (P = 0.007) and 72 hpf (P = 0.032). Dexamethasone was also significant in lowering the larvae’s heart rate in a dose- and time-dependent manner (P < 0.001). The two-way ANOVA results further indicated that dose, exposure time, and their interaction had significant effects on cardiometabolic function (P < 0.001).

Species delimitation is central to understanding biodiversity and its conservation, yet genetic divergence among sister lineages is often insufficient to demonstrate reproductive isolation or to resolve speciation unambiguously. This limitation is especially pronounced in marine invertebrates such as corals. Their slowly evolving genomes, cryptic diversity, and complex reproductive traits can obscure species boundaries. These challenges also characterize the Paramuricea-species complex occurring in the Iberian-Atlantic, whose members, including those studied here, commonly dominate deep coral forests. Within this complex, sympatrically occurring yellow and purple morphs exhibit little mitochondrial differentiation, despite evidence of partial genetic structuring. By characterizing gametogenesis, spawning time, and early life-history stages, we reveal pronounced prezygotic barriers between the yellow (broadcast spawning) and purple (surface-brooding) morphs, including consistent multi-year temporal separation and strongly contrasting fertilization environments. These differences extend into embryonic development, larval morphology, behavior, and settlement dynamics and reflect divergent dispersal strategies. Overall, our results provide direct biological evidence that the two morphs represent independent evolutionary lineages, supporting their recognition as distinct species. This model system represents a contemporary example of ecological speciation and may serve as a powerful model for future research on the genetic coupling between reproductive modes and life-history traits.

Abstract. Anggraini E, Zuhri S, Herlinda S, Lau WH, Muslim A, Irsan C, Suwandi S, Ramayudha R. 2026. Short Communication: COI-based molecular identification of bagworms (Psychidae) from an oil palm plantation in Muara Enim, South Sumatra, Indonesia. Biodiversitas 27 (2): d270212. https://doi.org/10.13057/biodiv/d270212. Bagworms (Lepidoptera: Psychidae) are major defoliating pests of oil palm in Southeast Asia, yet accurate species identification is often hindered by morphological similarity and phenotypic plasticity of larval cases. This study aimed to confirm the identity of bagworm species collected from an oil palm plantation in Muara Enim, South Sumatra, Indonesia, using an integrated approach combining mitochondrial Cytochrome Oxidase I (COI) barcoding and morphological assessment. A total of 12 larvae representing four field morphotypes were collected, of which 10 high-quality COI sequences were obtained. Nucleotide sequences were translated into amino acids, and phylogenetic reconstruction was performed using 211 aligned amino acid positions under the best-fit substitution model (MTVER+G4) selected by Bayesian Information Criterion. Maximum likelihood analysis recovered four distinct lineages corresponding to Mahasena corbetti, Pteroma pendula, a distinct Pteroma lineage, and Metisa plana. Specimens initially identified in the field as Clania tertia clustered within the genus Pteroma, indicating morphology-based misidentification. Despite moderate nucleotide similarity (~89-90%), amino acid-based phylogenetic reconstruction and larval morphology consistently supported its identification as M. plana. By integrating amino acid-based phylogenetic inference with morphological evidence, this study provides preliminary molecular confirmation of bagworm taxa from a single plantation site in South Sumatra and highlights the importance of combining molecular and morphological approaches for accurate pest identification.

ABSTRACT Larvae of Notodontidae employ diverse antipredator strategies, yet research has largely overlooked early instars. In this study, the ultramorphology and chaetotaxy of first-instar Fentonia ocypete were analysed, yielding new evidence for its defensive adaptations and systematic placement. The first-instar larvae of F. ocypete are peculiar for bearing five pairs of dorsal pigmented protuberances on the prothorax, the first three and the eighth abdominal segments, raised anal prolegs bearing reduced crochets and the heterogenetic setal arrangement on A3–A6. The relationship between larval morphology and defensive strategies is briefly discussed.

Expanded description and natural history of two insular Microhylid frogs of India, Microhyla chakrapanii (Pillai, 1977) and M. nakkavaram Garg, Chandrakasan, Gokulakrishnan, Chandramouli & Biju, 2022 (Anura: Microhylidae) with notes on breeding biology and larval morphology

Last instar larva and pupa of Hypera libanotidis Reitter, 1896 (Curculionidae: Hyperini) are described for the first time and compared with 44 other hyperine taxa. Larval morphology generally matches the diagnostic characters of Hyperini but shows distinctive traits, including thorn-like setae on conspicuous black protuberances, relatively long body setae, and dense spiculate coverings in larvae and pupae. Several unusual pupal characters, such as an atypical mesocoxal seta and a peculiar spiracular covering, further distinguish this species. These characters indicate close morphological affinity with species within the subgenus Eririnomorphus and also the genus Metadonus, suggesting a potentially close phylogenetic relationship. Biological observations confirm typical hyperine traits, including ectophytic larval feeding, cryptic coloration, and cocoon construction prior to pupation. Larval coloration, especially in early instars, partly corresponds with the host plant Libanotis pyrenaica. Larvae pupate in mesh-like cocoons on host plant remains, and no larval parasitism was observed. The species is associated with xerothermic loess grasslands, with adults apparently overwintering.

The marine Tanytarsini genus Yaetanytarsus Sasa, 1990 has been distinguished from Pontomyia Edwards, 1926 by the number of posterior parapod claws and the tapered form of abdominal segment VIII in the larval morphology. To evaluate these diagnostic characteristics, we identified the larvae of the three Yaetanytarsus species using mitochondrial cytochrome c oxidase subunit I (COI) DNA barcoding and subsequently examined their morphology. In total, 13 larvae and eight adults were analyzed. Larval sequences clustered unambiguously with conspecific adults, showing intraspecific K2P distances of 0.0–1.7% and interspecific distances exceeding 10%. The larvae of the three species (Y. boodleae (Tokunaga, 1933), Y. iriomeneus (Sasa & Suzuki, 2000), and Y. lamnicaudus (Tokunaga, 1964)) were examined and exhibited similar morphologies. Morphological comparison revealed that Y. lamnicaudus (Tokunaga, 1964) has 39–61 posterior parapod claws, which overlaps with the range in Pontomyia and indicates this characteristic is not uniformly reliable for separating these genera. Here, we provide the first detailed larval descriptions of these three species of Yaetanytarsus and demonstrate that COI barcoding is a robust tool for species identification in maritime Tanytarsini.

We report new fossil larval specimens that have characters of the group Megaloptera, i.e., are either megalopteran or megalopteran-like larvae from the Triassic, Cretaceous, or Eocene. Fossils from the latter two times are preserved in amber. One of the new fossils reveals that some earlier reported presumed megalopteran-like fossils, that have been already suspected to be beetles, are indeed more likely beetles of the group Myxophaga. A quantitative morphological comparison supports that most fossil megalopteran (and megalopteran-like) larvae did not differ significantly from extant megalopteran larvae, indicating no major losses of morphology over time. However, two newly reported fossil specimens from Kachin amber indeed separate from the other larvae, representing an extinct morphotype. The morphotype is characterised by a prominent terminal filament, indicating that the specimen is a representative of Sialidae. However, unlike most of the known larvae of this group, it possesses a rather elongate prothorax and strongly curved mandibles. These two characters are more commonly known in larvae of Corydalidae. It seems most likely that the presence of these characters in the new morphotype does not represent a plesisomorphy, but is more likely the product of convergent evolution.

ABSTRACT We present a detailed redescription of the larval morphology of a myrmecophilous beetle species associated with harvester ants of the genus Messor Forel, 1890. The description is consistent with Silvestri’s 112-year-old description of Attumbra lucida (Kraatz, 1852) larvae. Specimens for this study were identified as Attumbra lucida using DNA barcoding, demonstrating the effectiveness of molecular methods as well as precise modern morphological descriptions as tools for integrated taxonomic work. Additionally, we provide a preliminary phylogenetic tree of Cholevina Kirby, 1837, including several myrmecophilous genera. Our phylogenetic analyses revealed clear genetic differentiation between A. lucida and related taxa, supporting the morphological findings and confirming species identification. The calculated genetic distances, particularly the low distance of 0.0057 between the larval and adult stages of A. lucida, further validated the conspecificity of these stages. This is also the first complete, detailed account of larval morphology among myrmecophilous genera of Cholevinae. Morphological differences have been established between larvae of this myrmecophilous species and non-myrmecophilous Cholevini. Unique larval characters, including strong conical setae of the thorax and abdomen, very long and setose appendages (antennae, urogomphi and legs), provide material for discussion about host-guest interactions in ant nests.

Aedes aegypti is one of the main vectors of human arboviruses, thus is essential to discover new alternative tools for its control. Therefore, this study aimed to evaluate the larvicidal effects of the ethanolic extract of Piper arboreum leaves (EEPA) against Aedes aegypti. The extract was prepared in a 70% ethanol extractive solution and was rota-evaporated to obtain the crude extract. In the larvicide assay the third instar larvae (n = 20) were exposed to varying EEPA concentrations (25–200 µg/mL) for 24 h. The larvae were then transferred to fresh glass cups containing only chlorine-free water to assess the mortality rates over 72 h. In addition, larval morphology was evaluated in the experimental groups to determine alterations. Finally, the toxicity of EEPA was assessed in tests with Artemia salina. Our results showed that the larval mortality ranged from 17–100% in a dose-dependent manner after 72 h. The highest concentrations (150 and 200 µg/mL) were more effective than 25 µg/mL and the negative control group. The lethal concentration capable of killing 50% larvae (LC50) obtained for EEPA was 80.54 µg/mL (95%CI: 60.81–106.7 µg/mL). Morphological analyses revealed damage to the chitin layer of larvae exposed to EEPA, particularly at higher concentrations. The toxicity test of EEPA on A. salina showed an LC50 of 58 µg/mL (95%CI: 45–70.5µg/mL), which indicates elevated toxicity. Therefore, our results demonstrated that EEPA can be used as an alternative for controlling A. aegypti larvae, especially in artificial breeding sites, due to its high toxicity.

Styrene toxicity in the embryonic development of Celebes Medaka (Oryzias celebensis, Weber 1894): An assessment of the plastic monomer's impact.