Genetic diversity of the submerged macrophyte Ceratophyllum demersum depends on habitat hydrology and habitat fragmentation.

The adaptability of plant populations to a changing environment depends on their genetic diversity, which in turn is influenced by the degree of sexual reproduction and gene flow from distant areas. Aquatic macrophytes can reproduce both sexually and asexually, and their reproductive fragments are spread in various ways (e.g. by water). Although these plants are obviously exposed to hydrological changes, the degree of vulnerability may depend on the types of their reproduction and distribution, as well as the hydrological differences of habitats. The aim of this study was to investigate the genetic diversity of the cosmopolitan macrophyte Ceratophyllum demersum in hydrologically different aquatic habitats, i.e. rivers and backwaters separated from the main river bed to a different extent. For this purpose, the first microsatellite primer set was developed for this species. Using 10 developed primer pairs, a high level of genetic variation was explored in C. demersum populations. Overall, more than 80% of the loci were found to be polymorphic, a total of 46 different multilocus genotypes and 18 private alleles were detected in the 63 individuals examined. The results demonstrated that microsatellite polymorphism in this species depends on habitat hydrology. The greatest genetic variability was revealed in populations of rivers, where flowing water provides constant longitudinal connections with distant habitats. The populations of the hydrologically isolated backwaters showed the lowest microsatellite polymorphism, while plants from an oxbow occasionally flooded by the main river had medium genetic diversity. The results highlight that in contrast to species that spread independently of water flow or among hydrologically isolated water bodies, macrophytes with exclusive or dominant hydrochory may be most severely affected by habitat fragmentation, for example due to climate change.

Evolutionary significant units (ESUs) and functional conservation units (FCUs) in the Phengaris (Maculinea) nausithous populations of East-Central Europe.

The aim of this study was to analyse the level and structure of genetic and morphometric variation in the East-Central European populations of Phengaris (Maculinea) nausithous. On the basis of the life cycle of the species, we expected a low level of variation within the populations coupled with a relatively high level of differentiation among them. We also assumed that the differentiation among the populations has a regional pattern. In order to confirm these assumptions, we collected population samples from two regions within the Carpathian Basin (western Transdanubia and Transylvania) and from a region east of the Carpathian Mountains (Bukovina). The level of enzyme polymorphism and the amount of morphometric variation were investigated in the sampled populations. As the western (Transdanubia) and the eastern populations (Transylvania plus Bukovina) were suggested to belong to different subspecies (Rákosy et al. in Nota Lepidopterol 33:31-37, 2010), our working hypothesis was that these two groups of populations belong to different evolutionary significant units (ESUs). The results of all genetic analyses (PCA, Bayesian-clustering analysis and especially the UPGMA dendrogram) confirmed our assumption. The level of differentiation was higher between the western and eastern populations resulting in two monophyletic lineages of Phengaris (Maculinea) nausithous in East-Central Europe. This result suggests that these lineages can be considered as two different ESUs.

Development and characterization of novel SSR markers in the endangered endemic species Ferula sadleriana.

PREMISE: Ferula sadleriana (Apiaceae) is a polycarpic, perennial herb with a very limited range and small populations. It is listed as "endangered" on the IUCN Red List of Threatened Species. Microsatellite markers can contribute to conservation efforts by allowing the study of the genetic structure of its shrinking populations. METHODS AND RESULTS: We used a microsatellite-enriched library combined with an Illumina sequencing approach to develop simple sequence repeat markers in our target species. Out of 44 tested primer pairs, 22 provided specific products, and 13 showed heterologous amplification in the target species. Cross-species amplification was achieved at 20 and 19 loci in two congeneric species, F. soongarica and F. tatarica, respectively. CONCLUSIONS: The primers described here are the first tools that enable the population genetic characterization of F. sadleriana. Our results suggest a wider applicability in the genus Ferula.

Isolation and characterization of 15 SSR loci for the endangered European tetraploid species Gladiolus palustris (Iridaceae).

PREMISE: Gladiolus palustris (Iridaceae) is an endangered European perennial tetraploid herb with special conservation interest in the European Union. Microsatellite markers can serve as effective tools for the conservation genetics of this species. METHODS AND RESULTS: We utilized a 454 pyrosequencing approach to identify simple sequence repeat (SSR) regions in a microsatellite-enriched library. Of all SSR regions, 46 were screened for specific PCR amplification, and 15 were found to be applicable in the target species. We found 1.62-3.08 alleles per population (effective alleles: 1.58-2.08) that indicated moderate to high genetic diversity values (0.28-0.44) in three pilot populations. Cross-species amplification was less effective in G. imbricatus and G. tenuis. CONCLUSIONS: The primers reported here can be used for the population genetic characterization of G. palustris. They will help us to better understand the conservation genetics of this highly endangered species.

Roll with the fear: environment and state dependence of pill bug (Armadillidium vulgare) personalities.

Most studies on animal personality evaluate individual mean behaviour to describe individual behavioural strategy, while often neglecting behavioural variability on the within-individual level. However, within-individual behavioural plasticity (variation induced by environment) and within-individual residual variation (regulatory behavioural precision) are recognized as biologically valid components of individual behaviour, but the evolutionary ecology of these components is still less understood. Here, we tested whether behaviour of common pill bugs (Armadillidium vulgare) differs on the among- and within-individual level and whether it is affected by various individual specific state-related traits (sex, size and Wolbachia infection). To this aim, we assayed risk-taking in familiar vs. unfamiliar environments 30 times along 38 days and applied double modelling statistical technique to handle the complex hierarchical structure for both individual-specific trait means and variances. We found that there are significant among-individual differences not only in mean risk-taking behaviour but also in environment- and time-induced behavioural plasticity and residual variation. Wolbachia-infected individuals took less risk than healthy conspecifics; in addition, individuals became more risk-averse with time. Residual variation decreased with time, and individuals expressed higher residual variation in the unfamiliar environment. Further, sensitization was stronger in females and in larger individuals in general. Our results suggest that among-individual variation, behavioural plasticity and residual variation are all (i) biologically relevant components of an individual's behavioural strategy and (ii) responsive to changes in environment or labile state variables. We propose pill bugs as promising models for personality research due to the relative ease of getting repeated behavioural measurements.

Insulin/IGF Signaling and Life History Traits in Response to Food Availability and Perceived Density in the Cnidarian Hydra vulgaris.

Insulin/insulin-like growth factor signaling (IIS) is thought to be a central mediator of life history traits, but the generality of its role is not clear. Here, we investigated mRNA expression levels of three insulin-like peptide genes, the insulin-like receptor htk7, as well as several antioxidant genes, and the heat-shock protein hsp70 in the freshwater cnidarian Hydra vulgaris. Hydra polyps were exposed to a combination of different levels of food and perceived population density to manipulate life history traits (asexual reproduction and oxidative stress tolerance). We found that stress tolerance and the rate of asexual reproduction increased with food, and that these two effects were in significant interaction. Exposing animals to high perceived density resulted in increased stress tolerance or reduced reproduction only on lower food levels, but not on high food. The insulin-like receptor htk7 and the antioxidant gene catalase were significantly upregulated in the high density treatments. However, the expression level of insulin-like peptide genes, most antioxidant genes, and hsp70 were not affected by the experimental treatments. The higher expression level of htk7 may suggest that animals maintain a higher level of preparedness for insulin-like ligands at high population densities. However, the lack of difference between food levels suggests that IIS is not involved in regulating asexual reproduction and stress tolerance in hydra, or that its role is more subtle than a simple model of life history regulation would suggest.

A possible genetic basis for vulnerability in Euphydryas maturna (Lepidoptera: Nymphalidae).

Nearly all of the known populations of Scarce Fritillary, Euphydryas maturna (Linnaeus, 1758), are declining in Western and Central Europe. In order to identify the possible reasons for its vulnerability we surveyed the population genetics of this butterfly species using multi-locus genotype data. Females of our target species lay lots of eggs in one or two batches only and pre-hibernation caterpillars live and feed gregariously in a nest. As a consequence, a random unfavourable event can eliminate most offspring of a particular female resulting in a strong genetic drift effect combined with inbreeding. Thus, our hypothesis regarding the genetic composition of Scarce Fritillary populations suggests that: (1) there will be random fluctuations in allele frequencies from generation to generation; (2) populations should exhibit small effective sizes and a relatively high level of heterozygote deficiency, and; (3) the majority of the individuals in a population will be composed of the offspring of just a few females. In order to test these hypotheses, fine-scale genetic structure was studied in two subpopulations of a Hungarian Scarce Fritillary population for 4 consecutive years (generations) using enzyme polymorphism data. The results supported all of our assumptions. We detected random fluctuation in the frequency of several alleles, small effective population size and the index of heterozygote deficiency (F IS) indicated a considerable level of inbreeding in most samples. Furthermore, average values of relatedness were also fairly high, and we were able to identify 17 putative sib families in total with the two subpopulations based on estimation of individual gametic phases. Thus, the present study suggests that intrinsic factors (e.g. specific life history) might increase the sensitivity of a species to various threatening factors (e.g. habitat loss or fragmentation) and result in the vulnerability of the given species.