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Successful reproduction is critical to the persistence of at-risk species; however, reproductive characteristics are understudied in many wild species. New Zealand’s endemic tuatara ( Sphenodon punctatus) , the sole surviving member of the reptile order Rhynchocephalia, is restricted to 10% of its historic range. To complement ongoing conservation efforts, we collected and characterized mature sperm from male tuatara for the first time. Semen collected both during mating and from urine after courting contained motile sperm and had the potential for a very high percentage of viable sperm cells (98%). Scanning electron microscopy revealed a filiform sperm cell with distinct divisions: head, midpiece, tail, and reduced end piece. Finally, our initial curvilinear velocity estimates for tuatara sperm are 2–4 times faster than any previously studied reptile. Further work is needed to examine these trends at a larger scale; however, this research provides valuable information regarding reproduction in this basal reptile.

Tuatara are the sole extant species in the reptile order Rhynchocephalia. They are ecologically and evolutionarily unique, having been isolated geographically for ~84 million years and evolutionarily from their closest living relatives for ~250 million years. Here we report the tuatara gut bacterial community for the first time. We sampled the gut microbiota of translocated tuatara at five sanctuaries spanning a latitudinal range of ~1000 km within Aotearoa New Zealand, as well as individuals from the source population on Takapourewa (Stephens Island). This represents a first look at the bacterial community of the order Rhynchocephalia and provides the opportunity to address several key hypotheses, namely that the tuatara gut microbiota: (1) differs from those of other reptile orders; (2) varies among geographic locations but is more similar at sites with more similar temperatures and (3) is shaped by tuatara body condition, parasitism and ambient temperature. We found significant drivers of the microbiota in sampling site, tuatara body condition, parasitism and ambient temperature, suggesting the importance of these factors when considering tuatara conservation. We also derived a ‘core’ community of shared bacteria across tuatara at many sites, despite their geographic range and isolation. Remarkably, >70% of amplicon sequence variants could not be assigned to known genera, suggesting a largely undescribed gut bacterial community for this ancient host species. Tuatara, an endemic reptile to New Zealand, are a unique species in both their evolution and ecology, but have declined due to habitat loss and invasive predators. We here examine their microbial community to better understand their ecology and support their conservation. We found 70% of the tuatara gut to be populated with unknown bacterial genera and found significant impacts of temperature, parasitism and tuatara body condition on the tuatara gut community.

The morphological characteristics that impact feeding ecology in ectotherms, particularly reptiles, are poorly understood. We used morphometric measures and stable isotope analysis (carbon-13 and nitrogen-15) to assess the link between diet and functional morphology in an island population of an evolutionarily unique reptile, the tuatara (Sphenodon punctatus). First, we established a significant positive correlation between overall body size, gape size, and fat store in tuatara (n=56). Next, we describe the relationship between stable isotope profiles created from whole blood and nail trim samples and demonstrate that nail trims offer a low-impact method of creating a long-term dietary profile in ectotherms. We used nitrogen-15 values to assess trophic level in the population and found that tuatara on Takapourewa forage across multiple trophic levels. Finally, we found a significant relationship between gape size and carbon-13 (linear regression: P<0.001), with tuatara with large gapes showing dietary profiles that suggest a higher intake of marine (seabird) prey. However, whether body size or gape size is the primary adaptive characteristic allowing for more optimal foraging is yet unknown. This article has an associated First Person interview with the first author of the paper.

Invasive species provide an opportune system to investigate how populations respond to new environments. Baby's breath (Gypsophila paniculata) was introduced to North America in the 1800s and has since spread throughout the United States and western Canada. We used an RNA‐seq approach to explore how molecular processes contribute to the success of invasive populations with similar genetic backgrounds across distinct habitats. Transcription profiles were constructed from seedlings collected from a sand dune ecosystem in Petoskey, MI (PSMI), and a sagebrush ecosystem in Chelan, WA (CHWA). We assessed differential gene expression and identified SNPs within differentially expressed genes. We identified 1,146 differentially expressed transcripts across all sampled tissues between the two populations. GO processes enriched in PSMI were associated with nutrient starvation, while enriched processes in CHWA were associated with abiotic stress. Only 7.4% of the differentially expressed transcripts contained SNPs differing in allele frequencies of at least 0.5 between populations. Common garden studies found the two populations differed in germination rate and seedling emergence success. Our results suggest the success of G. paniculata in these two environments is likely due to plasticity in specific molecular processes responding to different environmental conditions, although some genetic divergence may be contributing to these differences. To better understand how molecular processes may be contributing to invasion success, we used an RNA‐seq approach to examine the differences in both gene expression profiles and identified SNP differences in differentially expressed genes for populations of Gypsophila paniculata (perennial baby's breath) growing at opposite ends of the species’ introduced range in the United States. We found that the majority of genes differentially expressed between these populations reflect the different environmental conditions between these two ecosystems; however, only 7.4% of the differentially expressed genes contained SNPs that differed in allele frequency between the two populations. We suggest that the success of invasive G. paniculata is likely the result of plasticity in molecular processes responding to different environmental conditions, although some genetic divergence over the past 100 years may also be contributing to these differences.

Gypsophila paniculata (baby’s breath) is a popular garden ornamental and horticultural crop introduced to North America in the late 1800s. After introduction it quickly spread, often forming dense monotypic stands and crowding out native species. To better understand this invasion, samples of G. paniculata from seven distinct populations spanning a portion of the plant’s invaded range within the United States (Washington, North Dakota, Minnesota, and Michigan) were collected and genotyped using 14 microsatellite loci. Population structure was inferred using both Bayesian and multivariate methods. The results suggest the presence of at least two genetic clusters among the seven sampling locations, with samples from Washington, North Dakota, Minnesota, and northwestern Michigan forming one genetic cluster and the second cluster consisting of two more southern sampling locations in Michigan. Public herbarium records were used to examine the invasion status (expansion vs. plateau phase) of the identified genetic clusters for G. paniculata. Invasion curves were created from a database of 351 herbarium collections dating from the late 1800s to current day. Results showed that time periods of invasion differed between the two genetics clusters, suggesting at least two invasion events. Patterns of reduced genetic diversity within the earlier invasion could reflect limited standing genetic variation during the initial period of this horticultural species’ import. This study emphasizes how anthropogenic influences can shape the study of invasive plant ecology, particularly when considering species popular in the botanical or horticultural industries.

Abstract The theoretical trade-off between immune and endocrine investment in mating animals has received mixed empirical support, particularly in reptiles. We investigated the relationship between male sexual characteristics, diet, and immune response to stress in an island population of tuatara (Sphenodon punctatus) across two mating seasons. Tuatara are promiscuous, with a highly skewed mating system where males face significant competition for access to mates and postcopulatory competition for fertilization success. We found that tuatara sperm viability and swim speed were negatively associated with male body condition and the ratio of heterophils to lymphocytes. Additionally, sperm swim speed was negatively associated with spine area, mite load, and the total number of circulating white blood cells, but was positively associated with tick number. This is likely a function of social dynamics in this system where larger male size predicts greater spatial overlap with potential rivals and increased tick load. Because the production of sexual characteristics may be costly, we also investigated the effect of diet on sperm quality. We did not identify an association between diet and sperm viability. However, sperm swim speed was negatively associated with carbon-13 and positively associated with nitrogen-15. We suspect that these results reflect the influence of seabird-based nutrients in this island ecosystem, particularly polyunsaturated fatty acid, and antioxidant damage on tuatara sperm. In total, these results provide evidence of a trade-off between pre- and post-copulatory sexual characteristics and the immune and endocrine systems in male tuatara.

Successful reproduction is critical to the persistence of at-risk species; however, reproductive characteristics are understudied in many wild species. New Zealand's endemic tuatara (Sphenodon punctatus), the sole surviving member of the reptile order Rhynchocephalia, is restricted to 10% of its historic range. To complement ongoing conservation efforts, we collected and characterized mature sperm from male tuatara for the first time. Semen collected both during mating and from urine after courting contained motile sperm and had the potential for a very high percentage of viable sperm cells (98%). Scanning electron microscopy revealed a filiform sperm cell with distinct divisions: head, midpiece, tail, and reduced end piece. Finally, our initial curvilinear velocity estimates for tuatara sperm are 2-4 times faster than any previously studied reptile. Further work is needed to examine these trends at a larger scale; however, this research provides valuable information regarding reproduction in this basal reptile.

We identified considerable variation in male fertility in wild tuatara, an evolutionarily unique reptile. Our findings show that tuatara sperm morphology is relatively conserved but sperm viability and swim speed vary significantly among matings. Thus, we strongly suggest that variation in male fertility be considered during future conservation actions. Abstract Managing a species of conservation concern can be best achieved when there is information on the reproductive physiology of both sexes available; however, many species lack this critical, baseline information. One such species, the tuatara (Sphenodon punctatus), is the last surviving member of one of the four reptile orders (Rhynchocephalia) and is the only reptile known to lack a male intromittent organ. Culturally and evolutionarily significant, the conservation of this species is a global priority for the maintenance of biodiversity. In light of this, we characterized the morphology, viability and swim speed of mature tuatara sperm for the first time. We found that tuatara sperm are filiform and bear the remarkably conserved three-part sperm structure seen across the animal kingdom. Tuatara sperm are long (mean total length 166 μm), with an approximate head:midpiece:tail ratio of 15:1:17. While tuatara sperm are capable of high levels of within-mating viability (94.53%), the mean viability across all samples was 58.80%. Finally, tuatara sperm had a mean curvilinear velocity swim speed (μ × s − 1) of 82.28. At the population level, there were no differences in viability or mean swim speed between sperm collected from a male’s first mating of a season and repeat matings; however, the maximum sperm swim speed increased in observed repeated matings relative to first matings. Interestingly, faster sperm samples had shorter midpieces, but had greater viability and longer head and tail sections. This work expands our understanding of male reproductive characteristics and their variation to a new order, provides wild references for the assessment of captive individuals, lays the groundwork for potential assisted reproductive techniques and highlights variation in male reproductive potential as an important factor for consideration in future conservation programs for this unique species.

New Zealand has three species of endemic amphibians in the genus Leiopelma, all of which are threatened with extinction. The primary threats to their persistence are mammalian predators and habitat loss, and the translocation of these frogs into restored habitat is a common method of conservation. The Maud Island frog (Leiopelma hamiltoni), is considered terrestrial with habitat needs centering on complex boulder-strewn habitat. However, during recent surveys of a translocated population, we found repeated use of arboreal habitat within this species. Further, trail camera observations made several months later confirm this habitat use to persist across seasons. While the function of this arboreal behaviour is unknown, it suggests Maud Island frogs use more complex, vertical habitat than previously thought, which should be considered in future conservation efforts.

First Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping researchers promote themselves alongside their papers. Sarah K. Lamar is first author on ‘ Investigating the link between morphological characteristics and diet in an island population of omnivorous reptiles (Sphenodon punctatus)’, published in BiO. Sarah is a PhD candidate and personal research assistant to the Head of the School of Biological Sciences in the lab of Professor Nicola Nelson and Dr. Diane Ormsby (co-chairs) at Victoria University of Wellington. Her research interests rest at the intersection of herpetology, evolution, statistics, and conservation.