Aquatic Larval Stage Research Articles

Genomic resources of aquatic Lepidoptera, Elophila obliteralis and Hyposmocoma kahamanoa, reveal similarities with Trichoptera in amino acid composition of major silk genes.

While most species of butterflies and moths (Lepidoptera) have entirely terrestrial life histories, ∼0.5% of the described species are known to have an aquatic larval stage. Larvae of aquatic Lepidoptera are similar to caddisflies (Trichoptera) in that they use silk to anchor themselves to underwater substrates or to build protective cases. However, the physical properties and genetic elements of silks in aquatic Lepidoptera remain unstudied, as most research on lepidopteran silk has focused on the commercially important silkworm, Bombyx mori. Here, we provide high-quality PacBio HiFi genome assemblies of 2 distantly-related aquatic Lepidoptera species [Elophila obliteralis (Pyraloidea: Crambidae) and Hyposmocoma kahamanoa (Gelechioidea: Cosmopterigidae)]. As a step toward understanding the evolution of underwater silk in aquatic Lepidoptera, we used the genome assemblies and compared them to published genetic data of aquatic and terrestrial Lepidoptera. Sequences of the primary silk protein, h-fibroin, in aquatic moths have conserved termini and share a basic motif structure with terrestrial Lepidoptera. However, these sequences were similar to aquatic Trichoptera in that the percentage of positively and negatively charged amino acids was much higher than in terrestrial Lepidoptera, indicating a possible adaptation of silks to aquatic environments.

Outbreeding reduces survival during metamorphosis in a headwater stream salamander.

Assessing direct fitness effects of individual genetic diversity is challenging due to the intensive and long-term data needed to quantify survival and reproduction in the wild. But resolving these effects is necessary to determine how inbreeding and outbreeding influence eco-evolutionary processes. We used 8 years of capture-recapture data and single nucleotide polymorphism genotypes for 1906 individuals to test for effects of individual heterozygosity on stage-specific survival probabilities in the salamander Gyrinophilus porphyriticus. The life cycle of G. porphyriticus includes an aquatic larval stage followed by metamorphosis into a semi-aquatic adult stage. In our study populations, the larval stage lasts 6-10 years, metamorphosis takes several months, and lifespan can reach 20 years. Previous studies showed that metamorphosis is a sensitive life stage, leading us to predict that fitness effects of individual heterozygosity would occur during metamorphosis. Consistent with this prediction, monthly probability of survival during metamorphosis declined with multi-locus heterozygosity (MLH), from 0.38 at the lowest MLH (0.10) to 0.06 at the highest MLH (0.38), a reduction of 84%. Body condition of larvae also declined significantly with increasing MLH. These relationships were consistent in the three study streams. With evidence of localised inbreeding within streams, these results suggest that outbreeding disrupts adaptations in pre-metamorphic and metamorphic individuals to environmental gradients along streams, adding to evidence that headwater streams are hotspots of microgeographic adaptation. Our results also underscore the importance of incorporating life history in analyses of the fitness effects of individual genetic diversity and suggest that metamorphosis and similar discrete life stage transitions may be critical periods of viability selection.

The Perpetual Vector Mosquito Threat and Its Eco-Friendly Nemeses.

Mosquitoes are the most notorious arthropod vectors of viral and parasitic diseases for which approximately half the world's population, ~4,000,000,000, is at risk. Integrated pest management programs (IPMPs) have achieved some success in mitigating the regional transmission and persistence of these diseases. However, as many vector-borne diseases remain pervasive, it is obvious that IPMP successes have not been absolute in eradicating the threat imposed by mosquitoes. Moreover, the expanding mosquito geographic ranges caused by factors related to climate change and globalization (travel, trade, and migration), and the evolution of resistance to synthetic pesticides, present ongoing challenges to reducing or eliminating the local and global burden of these diseases, especially in economically and medically disadvantaged societies. Abatement strategies include the control of vector populations with synthetic pesticides and eco-friendly technologies. These "green" technologies include SIT, IIT, RIDL, CRISPR/Cas9 gene drive, and biological control that specifically targets the aquatic larval stages of mosquitoes. Regarding the latter, the most effective continues to be the widespread use of Lysinibacillus sphaericus (Ls) and Bacillus thuringiensis subsp. israelensis (Bti). Here, we present a review of the health issues elicited by vector mosquitoes, control strategies, and lastly, focus on the biology of Ls and Bti, with an emphasis on the latter, to which no resistance has been observed in the field.

THE TADPOLES OF FROGS AND TOADS FOUND IN THE LOWLANDS OF NORTHERN COLOMBIA

Fifty-nine native species and two introduced species of frogs and toads occur in the lowlands of the Caribbean Region of Colombia. Of these 61 species, 54 have life cycles that include an aquatic larval stage. In order to promote ecological studies on these species, a key with illustrations (of 29 species) are provided to allow confident identification for most tadpoles encountered in these lowlands.

A laboratory experimental assessment of the sensibility of Rana temporaria tadpoles to the effects of car traffic-associated seismic disturbances

"Vibrations generated by road traffic are considered to be a form of physical environmental pollution. Nonetheless, the effect of this disturbance in natural habitats, and in particular on the aquatic stage of amphibians, received very little attention from the scientific community. This study aims to assess the direct effect of mechanical waves and the consequent water turbidity on the aquatic larval stage of Rana temporaria by exposing an experimental group to laboratory-induced vibrations and comparison with a non-exposed control group. Our results show that this kind of pollution had no significant effect on the development rate, the length of the larval period, and the mortality of the larvae. However, we identified a significant effect on the size of animals, both during the larval period, and at metamorphosis. This result raises concern about the long-term risks to the amphibian population exposed to this type of low-profile pollution. Keywords: development, growth, metamorphosis, amphibian performance, traffic-related pollution"

Stages of Development and Metamorphosis of Tree Frog Rhacophorus Bipunctatus (Amphibia, Anura, Rhacophoridae)

Amphibians are the highest vertebrate group to retain an essentially naked egg and the only vertebrate group which has an aquatic larval stage and a terrestrial adult phase. One of the prominent life history characteristics common to most living amphibians is the presence of an aquatic larval period, which immediately follows the initial embryonic development after fertilization and ends with the completion of metamorphosis. Metamorphosis in anurans involves resorption of the tail, development of the front and hind limbs and large changes in most organ system. Proper staging of the larval period is therefore necessary for accurate comparison of developmental stages in different organisms. Hence, several workers [1-3] have reported on tables of normal stages of development for a number of species. Keeping in view the paucity of information on the development and metamorphosis of tree frogs from Meghalaya, it was decided to study the development and metamorphosis of the tree frog Rhacophorus bipunctatus at Cherrepunjee, Meghalaya. The present study was conducted during the breeding season (April to August). In the present study it was found that, the development and metamorphosis of Rhacophorus bipunctatus was completed in about 59 – 60 days under natural environment as well as in the laboratory condition. This tree frog was observed to be dependent on the rain fed pools at the breeding sites to complete their life cycle.

Synergistic survival-related effects of larval exposure to an aquatic pollutant and food stress get stronger during and especially after metamorphosis and shape fitness of terrestrial adults

To improve the ecological risk assessment of aquatic pollutants it is needed to study their effects not only in the aquatic larval stage, but also in the terrestrial adult stage of the many animals with a complex life cycle. This remains understudied, especially with regard to interactive effects between aquatic pollutants and natural abiotic stressors. We studied effects of exposure to the pesticide DNP (2,4-Dinitrophenol) and how these were modulated by limited food availability in the aquatic larvae, and the possible delayed effects in the terrestrial adults of the damselfly Lestes viridis. Our results revealed that DNP and low food each had large negative effects on the life history, behaviour and to a lesser extent on the physiology of not only the larvae, but also the adults. Food limitation magnified the negative effects of DNP as seen by a strong decline in larval survival, metamorphosis success and adult lifespan. Notably, the synergism between the aquatic pollutant and food limitation for survival-related traits was stronger in the non-exposed adults than in the exposed larvae, likely because metamorphosis is stressful itself. Our results highlight that identifying effects of aquatic pollutants and synergisms with natural abiotic stressors, not only in the aquatic larval but also in the terrestrial adult stage, is crucial to fully assess the ecological impact of aquatic pollutants and to reveal the impact on the receiving terrestrial ecosystem through a changed aquatic-terrestrial subsidy.

Amphibian Dispersal Traits Not Impacted by Triclopyr Exposure during the Juvenile Stage

Exposure to agrochemicals can have lethal and sublethal effects on amphibians. Most toxicology studies only examine exposure during the aquatic larval stage. Survival of the juvenile stage is the most important for population persistence and it is critical to understand the potential impacts of exposure during this life stage. We investigated how short-term exposure to triclopyr, an herbicide commonly used in forestry management, might impact several juvenile traits. To determine if juveniles perceived exposure as an environmental stressor, we measured their release of corticosterone. We also examined dispersal traits by measuring foraging and hopping behavior. We found no evidence that exposure negatively impacted these traits or was a stressor. Our results provide a preliminary assessment of the potential impact of triclopyr on juvenile amphibians, but we recommend additional research on the effects of agrochemicals on juvenile amphibians.

Paedomorphic salamanders are larval in form and patterns of limb emergence inform life cycle evolution.

Amphibians undergo a variety of post-embryonic transitions (PETr) that are partly governed by thyroid hormone (TH). Transformation into a terrestrial form follows an aquatic larval stage (biphasic) or precedes hatching (direct development). Some salamanders maintain larval characteristics and an aquatic lifestyle into adulthood (paedomorphosis), which obscures the conclusion of their larval period. Paedomorphic axolotls exhibit elevated TH during early development that is concomitant with transcriptional reprogramming and limb emergence. A recent perspective suggested this cryptic TH-based PETr is uncoupled from metamorphosis in paedomorphs and concludes the larval period. This led to their question: "Are paedomorphs actual larvae?". To clarify, paedomorphs are only considered larval in form, even though they possess some actual larval characteristics. However, we strongly agree that events during larval development inform amphibian life cycle evolution. We build upon their perspective by considering the evolution of limb emergence and metamorphosis. Limbless hatchling larval salamanders are generally associated with ponds, while limbed larvae are common to streams and preceded the evolution of direct development. Permian amphibians had limbed larvae, so their PETr was likely uncoupled from metamorphosis, equivalent to most extant biphasic and paedomorphic salamanders. Coupling of these events was likely derived in frogs and direct developing salamanders.

Early Development Drives Variation in Amphibian Vulnerability to Global Change

Understanding how natural selection determines species’ life histories can reveal their resilience or sensitivity to anthropogenic changes. For example, the safe harbor hypothesis posits that natural selection will favor life histories that maximize the time spent in the safest life stages; a second theoretical prediction suggests that species with complex life histories will maximize the growth potential of a life stage relative to its safety. Amphibians exhibit complex life histories, with a diversity of developmental strategies occurring across taxa. Many strategies involve the complete elimination of a particular life stage, and thus provide an excellent opportunity to evaluate the main tenets of the safe harbor hypothesis and understand the consequences of this developmental variation for conservation of threatened amphibians. We develop a general framework for understanding developmental life histories of amphibians – including the special cases of paedomorphism, direct development, and viviparity – based on the relative growth potential and safety offered by aquatic and terrestrial habitat, which we tested using a global trait database. We then compare the IUCN Red List status of species differing in developmental mode, revealing that most fully aquatic species and species with an aquatic larval stage are currently of Least Concern, despite the fact that freshwater habitats are being lost at a much faster rate compared with terrestrial ecosystems. The higher proportion of direct developing and viviparous species that are threatened can be attributed to their smaller ranges, the fact that they are more likely to be found in rainforest habitats, and their relatively slow life histories. We conclude that an amphibian’s developmental mode reflects the relative costs and benefits of different habitats, and that this could contribute to the resilience or vulnerability of amphibians to future anthropogenic change.

Climate drivers of adult insect activity are conditioned by life history traits.

Insect phenological lability is key for determining which species will adapt under environmental change. However, little is known about when adult insect activity terminates and overall activity duration. We used community-science and museum specimen data to investigate the effects of climate and urbanisation on timing of adult insect activity for 101species varying in life history traits. We found detritivores and species with aquatic larval stages extend activity periods most rapidly in response to increasing regional temperature. Conversely, species with subterranean larval stages have relatively constant durations regardless of regional temperature. Species extended their period of adult activity similarly in warmer conditions regardless of voltinism classification. Longer adult durations may represent a general response to warming, but voltinism data in subtropical environments are likely underreported. This effort provides a framework to address the drivers of adult insect phenology at continental scales and a basis for predicting species response to environmental change.

Clothianidin alters leukocyte profiles and elevates measures of oxidative stress in tadpoles of the amphibian, Rana pipiens

Neonicotinoid pesticide use is widespread and highly debated, as evidenced by recent attention received from the public, academics and pesticide regulatory agencies. However, relatively little is known about the physiological effects of neonicotinoid insecticides on aquatic vertebrates. Amphibians (larval stages in particular) are excellent vertebrate bioindicators in aquatic systems due to their risk of exposure and sensitivity to environmental stressors. Previous work with wood frog (Rana sylvatica) tadpoles exposed to formulated products containing thiamethoxam or clothianidin in outdoor mesocosms found significant shifts in leukocyte profiles, suggesting the tadpoles were physiologically stressed. The main objective of the present study was to characterize this stress response further using complementary measures of stress after exposure to clothianidin on northern leopard frogs (Rana pipiens) during their aquatic larval stages. Laboratory static-renewal exposures were conducted over eight weeks with the technical product clothianidin at 0, 0.23, 1, 10 and 100 μg/L, and diquat dibromide at 532 μg/L was used as a positive control. We assessed tadpole leukocyte profiles and measures of oxidative stress as these sub-lethal alterations could affect amphibian fitness. We found changes in several types of leukocytes at 1 and 10 μg/L, suggesting that these tadpoles exhibited signs of mild physiological stress. Clothianidin also induced an oxidative stress response at 0.23, 1 and 100 μg/L. However, we found no differences in survival, growth, development time or hepatosomatic index in frogs exposed to clothianidin. Our study indicates that tadpoles chronically exposed to clothianidin have increased stress responses, but in the absence of concentration-response relationships and effects on whole-organism endpoints, the implications on the overall health and fitness of these changes are unclear.

Evolution of cold tolerance and thermal plasticity in life history, behaviour and physiology during a poleward range expansion

Many species that are moving polewards encounter novel thermal regimes to which they have to adapt. Therefore, rapid evolution of thermal tolerance and of thermal plasticity in fitness-related traits in edge populations can be crucial for the success and speed of range expansions. We tested for adaptation in cold tolerance and in life history, behavioural and physiological traits and their thermal plasticity during a poleward range expansion. We reconstructed the thermal performance curves of life history (survival, growth and development rates), behaviour (food intake) and cold tolerance (chill coma recovery time) in the aquatic larval stage of the damselfly Ischnura elegans that is currently showing a poleward range expansion in northern Europe. We studied larvae from three edge and three core populations using a common-garden experiment. Consistent with the colder annual temperatures, larvae at the expansion front evolved an improved cold tolerance. The edge populations showed no overall (across temperatures) evolution of a faster life history that would improve their range-shifting ability. Moreover, consistent with damselfly edge populations from colder latitudes, edge populations evolved at the highest rearing temperature (28°C) a faster development rate, likely to better exploit the rare periods with higher temperatures. This was associated with a higher food intake and a lower metabolic rate. In conclusion, our results suggest that the edge populations rapidly evolved adaptive changes in trait means and thermal plasticity to the novel thermal conditions at the edge front. Our results highlight the importance of considering besides trait plasticity and the evolution of trait means, also the evolution of trait plasticity to improve forecasts of responses to climate change.

Genetic characteristics and phylogeography of the habitat generalist mayfly Ecdyonurus yoshidae (Ephemeroptera: Heptageniidae) in the Japanese archipelago

AbstractBecause of their early divergence in insect evolution, unique aquatic larval stage, and low dispersal ability, many mayfly species exhibit genetic structures that accurately reflect geological history and paleoclimatic changes. The present study investigated the genetic characteristics of Ecdyonurus yoshidae Takahashi (Ephemeroptera: Heptageniidae), a mayfly that inhabits a variety of freshwater habitats in Japan. Mitochondrial cytochrome c oxidase subunit I (COI) and 16S ribosomal RNA (16S rRNA) gene sequences were generated from 209 mayfly specimens that were collected from 109 sites in Japan. A total of 145 haplotypes were detected, and nine of the lineages exhibited geographical regionality, with one lineage being endemic to Lake Biwa. The haplotype network was “bottleneck type” and included both star‐like structures and missing (or unobserved) haplotypes. Together, the haplotype network and FST values indicated that the Fukuejima Island group (Clade I) was genetically distinct from groups on the island of Kyushu, which is separated from Fukuejima Island by the Gotonada Sea. The common ancestor of E. yoshidae lineages in Japan was estimated to have diverged 1.14 mega‐annum (Ma) (95% highest posterior density interval, 0.55–1.78 Ma), and more regional genetic diversities were generated during the Middle to Late Pleistocene. Genetically distinct lineages of eastern and western Japan were separated by the Kinki Triangle region in central Japan. The genetic diversity of the habitat generalist E. yoshidae increased during the Middle and Late Pleistocene, when crustal movement and climate change in the Japanese archipelago occurred simultaneously.

How far can EPTs fly? A comparison of empirical flying distances of riverine invertebrates and existing dispersal metrics

The species composition of a community is driven by the dispersal capacity of the species forming that community and their ecological niche. While the ecological niches of EPTs (Ephemeroptera, Plecoptera and Trichoptera) are well-studied due to their wide use as indicators for the ecological status of freshwater ecosystems, their dispersal capacity has not yet been accurately characterized. Dispersion of the merolimnic EPT species during the terrestrial aerial adult stage is of special importance because the distance dispersed by active flight or passive wind drift is usually much larger compared to dispersion during the aquatic larval stage by active crawling or by drifting downstream.The aerial dispersal distance has been directly measured for only a small number of EPT species. For most other species, the dispersal capacity is assessed indirectly using species’ traits that are mainly based on expert judgement and dispersal indices derived from trait information. In this study, we compiled a database of European EPTs’ aerial dispersal distances reported in empirical studies and compared them to the dispersal capacity of the species as described by five different dispersal indices (original and modified versions of Li’s Dispersal Capacity Metric DCM and Sarremejane’s Species Flying Propensity SFP as well as relative wing length).The database included empirical data on 180 species, comprising 9.3% of European EPT species. Most data came from trap experiments with traps located at different distances from the assumed emergence point. Since the distance classes differed between studies and had to be translated to a fixed set of four distance classes here, several species had to be assigned to more than one class. To account for this uncertainty, five ordered logistic regression models, each one with a dispersal index as predictor and the ordinal-scaled aerial dispersal distance as response, were bootstrapped 10,000 times. In each run, species belonging to several distance classes were randomly assigned to a single class out of all possible classes. Since wing length had no significant effect on aerial dispersal distance in any of the 10,000 bootstrap runs, we question the use of this anatomical trait as an indicator for the aerial dispersal capacity. In contrast, a modified version of the DCM index was consistently related to the aerial dispersal distances (96%). The original SFP index had a significant effect in 100% of the model runs, indicating that this index is very well-suited as an indicator for the aerial dispersal capacity of European EPT species.This study facilitates the assessment of European EPT flying distances by providing a compilation of empirical data on the topic and by recommending an accurate indirect method when empirical data is not available.

Does the Presence of Other Egg Rafts and Conspecific Larvae Encourage Oviposition by the Mosquito, Culex sitiens (Diptera: Culicidae)?

Mosquitoes include many major disease vectors and are often controlled in their aquatic larval stage, since they are living in defined habitats. However, non-chemical methods of control are influenced by the female oviposition behavior, and this is affected by many factors. Many mosquito species choose to oviposit on water containing egg raft pheromones (which have thus been used in control), showing another female has selected that pool as being best. However, Culex sitiens did not respond chemically to water previously containing egg rafts, but unlike most species, did strongly respond visually to artificial black egg rafts floating on the surface. Oviposition increased as the number of artificial egg rafts increased up to six, but more rafts gave no further increase. However, even nine egg rafts had no repellent effect, despite the high probability of larval overcrowding and thus starvation. Altering the pattern with which five rafts were interconnected and also altering the size of individual rafts seemed to show that the mosquitoes were responding more to total raft area rather than number. The presence of either 2nd instar or 4th (final) instar conspecific larvae in the water can be detected chemically but did not influence oviposition, either positively or negatively. Conspecific larvae show the water is suitable for oviposition, but they are competitors for the available food and so many studies have shown especially older larvae to be repellent to oviposition. Culex sitiens was thus not responding chemically to either eggs or larvae but unusually had a visual response.

Inter- and intraspecific variation in juvenile metabolism and water loss among five biphasic amphibian species.

Population persistence is informed by the ability of individuals to cope with local abiotic conditions, which is commonly mediated by physiological traits. Among biphasic amphibians, juveniles-which are infrequently studied but play a key role in amphibian population dynamics-are the first life stage to experience terrestrial conditions following the aquatic larval stage. To illuminate phenotypic variation that may allow juveniles to survive the physiological challenges presented by this transition, we examined respiratory surface area water loss (RSAWL) and standard metabolic rates (SMR) among juveniles reared under common larval conditions for five salamander species (Ambystoma annulatum, A. maculatum, A. opacum, A. talpoideum, and A. texanum) collected across ~ 200km of latitude in Missouri, USA. We found that SMR described 34% of variation in RSAWL, suggesting that physiological water conservation may be limited by energetic regulation among these species, and vice versa. On average, species differed in juvenile SMR and residual values of RSAWL (corrected for body size/shape) by 0.04mL [Formula: see text] and 0.16, respectively, possibly because of distinct species ecologies. For example, A. annulatum had higher SMR and RSAWL compared to broadly distributed study species, potentially associated with a relatively narrow range of environmental conditions experienced across the small geographic distribution of A. annulatum. Latitude correlated negatively with temperature and precipitation, and positively with RSAWL, suggesting that variation in RSAWL may be adaptive to local conditions. We provide evidence that species differences likely have a genetic basis, reflecting selection favoring species divergence to effectively use distinct microhabitats.

EMERGENCE TRAP FOR THE COLLECTION OF EXUVIAE AND ADULT OF ODONATA

Odonates have aquatic larval stages and terrestrial adults. The extreme change in habitat occupation during their life cycle means that combined collection methods, capable of providing data for both larvae and adults, are scarce and are often inefficient. Given this, we applied a method for the collection of specimens of both life phases using emergence traps. During fieldwork, 78 emergence events were recorded for 15 species. We also briefly discuss the emergence pattern of the recorded species. We believe the information obtained here provide an important contribution to the understanding of the ecology and basic biology of Neotropical odonate species, as well as helping to solve the taxonomic problems associated with the identification of larvae.

Developmental life history is associated with variation in rates of climatic niche evolution in a salamander adaptive radiation.

Rates of climatic niche evolution vary widely across the tree of life and are strongly associated with rates of diversification among clades. However, why the climatic niche evolves more rapidly in some clades than others remains unclear. Variation in life history traits often plays a key role in determining the environmental conditions under which species can survive, and therefore, could impact the rate at which lineages can expand in available climatic niche space. Here, we explore the relationships among life-history variation, climatic niche breadth, and rates of climatic niche evolution. We reconstruct a phylogeny for the genus Desmognathus, an adaptive radiation of salamanders distributed across eastern North America, based on nuclear and mitochondrial genes. Using this phylogeny, we estimate rates of climatic niche evolution for species with long, short, and no aquatic larval stage. Rates of climatic niche evolution are unrelated to the mean climatic niche breadth of species with different life histories. Instead, we find that the evolution of a short larval period promotes greater exploration of climatic space, leading to increased rates of climatic niche evolution across species having this trait. We propose that morphological and physiological differences associated with variation in larval stage length underlie the heterogeneous ability of lineages to explore climatic niche space. Rapid rates of climatic niche evolution among species with short larval periods were an important dimension of the clade's adaptive radiation and likely contributed to the rapid rate of lineage accumulation following the evolution of an aquatic life history in this clade. Our results show how variation in a key life-history trait can constrain or promote divergence of the climatic niche, leading to variation in rates of climatic niche evolution among species.

Comparative landscape genetics reveals the evolution of viviparity reduces genetic connectivity in fire salamanders.

Evolutionary changes in reproductive mode may affect co-evolving traits, such as dispersal, although this subject remains largely underexplored. The shift from aquatic oviparous or larviparous reproduction to terrestrial viviparous reproduction in some amphibians entails skipping the aquatic larval stage and, thus, greater independence from water. Accordingly, amphibians exhibiting terrestrial viviparous reproduction may potentially disperse across a wider variety of suboptimal habitats and increase population connectivity in fragmented landscapes compared to aquatic-breeding species. We investigated this hypothesis in the fire salamander (Salamandra salamandra), which exhibits both aquatic- (larviparity) and terrestrial-breeding (viviparity) strategies. We genotyped 426 larviparous and 360 viviparous adult salamanders for 13 microsatellite loci and sequenced a mitochondrial marker for 133 larviparous and 119 viviparous individuals to compare population connectivity and landscape resistance to gene flow within a landscape genetics framework. Contrary to our predictions, viviparous populations exhibited greater differentiation and reduced genetic connectivity compared to larviparous populations. Landscape genetic analyses indicate viviparity may be partially responsible for this pattern, as water courses comprised a significant barrier only in viviparous salamanders, probably due to their fully terrestrial life cycle. Agricultural areas and, to a lesser extent, topography also decreased genetic connectivity in both larviparous and viviparous populations. This study is one of very few to explicitly demonstrate the evolution of a derived reproductive mode affects patterns of genetic connectivity. Our findings open avenues for future research to better understand the eco-evolutionary implications underlying the emergence of terrestrial reproduction in amphibians.