Plastic and genomic change of a newly established lizard population following a founder event.

Understanding how phenotypic divergence arises among natural populations remains one of the major goals in evolutionary biology. As part of competitive exclusion experiment conducted in 1971, 10 individuals of Italian wall lizard (Podarcis siculus (Rafinesque-Schmaltz, 1810)) were transplanted from Pod Kopiste Island to the nearby island of Pod Mrcaru (Adriatic Sea). Merely 35 years after the introduction, the newly established population on Pod Mrcaru Island had shifted their diet from predominantly insectivorous towards omnivorous and changed significantly in a range of morphological, behavioural, physiological and ecological characteristics. Here, we combine genomic and quantitative genetic approaches to determine the relative roles of genetic adaptation and phenotypic plasticity in driving this rapid phenotypic shift. Our results show genome-wide genetic differentiation between ancestral and transplanted population, with weak genetic erosion on Pod Mrcaru Island. Adaptive processes following the founder event are indicated by highly differentiated genomic loci associating with ecologically relevant phenotypic traits, and/or having a putatively adaptive role across multiple lizard populations. Diverged traits related to head size and shape or bite force showed moderate heritability in a crossing experiment, but between-population differences in these traits did not persist in a common garden environment. Our results confirm the existence of sufficient additive genetic variance for traits to evolve under selection while also demonstrating that phenotypic plasticity and/or genotype by environment interactions are the main drivers of population differentiation at this early evolutionary stage.

PCE simulation toolkit: a platform for perceptual crossing experiment research.

The Perceptual Crossing Experiment (PCE) has been the object of study for over a decade, and aims at explaining how we perceive, interact with, and understand each other in real-time. In addition to human participant studies, a number of computational models have investigated how virtual agents can solve this task. However, the set of implementation choices that has been explored to date is rather limited, and the large number of variables that can be used make it very difficult to replicate the results. The main objective of this paper is to describe the PCE Simulation Toolkit we have developed and published as an open-source repository on GitHub. We hope that this effort will help make future PCE simulation results reproducible and advance research in the understanding of possible behaviors in this experimental paradigm. At the end of this paper, we present two case studies of evolved agents that demonstrate how parameter choices affect the simulations.

Ecological and Convergent Validity of Experimentally and Dynamically Assessed Capacity for Social Contingency Detection Using the Perceptual Crossing Experiment in Adolescence.

The Perceptual Crossing Experiment (PCE) captures the capacity for social contingency detection using real-time social interaction dynamics but has not been externally validated. We tested ecological and convergent validity of the PCE in a sample of 208 adolescents from the general population, aged 11 to 19 years. We expected associations between PCE performance and (a) quantity and quality of social interaction in daily life, using Experience Sampling Methodology (ESM; ecological validity) and (b) self-reported social skills using a questionnaire (convergent validity). We also expected PCE performance to better explain variance in ESM social measures than self-reported social skills. Multilevel analyses showed that only self-reported social skills were positively associated with social experience of company in daily life. These initial results do not support ecological and convergent validity of the PCE. However, fueled by novel insights regarding the complexity of capturing social dynamics, we identified promising methodological advances for future validation efforts.

B Chromosomes in Free-Living Flatworms of the Genus Macrostomum (Platyhelminthes, Macrostomorpha).

B chromosomes (Bs) or supernumerary chromosomes are extra chromosomes in the species karyotype that can vary in its copy number. Bs are widespread in eukaryotes. Usually, the Bs of specimens collected from natural populations are the object of the B chromosome studies. We applied another approach analyzing the Bs in animals maintained under the laboratory conditions as lines and cultures. In this study, three species of the Macrostomum genus that underwent a recent whole-genome duplication (WGD) were involved. In laboratory lines of M. lignano and M. janickei, the frequency of Bs was less than 1%, while in the laboratory culture of M. mirumnovem, it was nearer 30%. Their number in specimens of the culture varied from 1 to 14. Mosaicism on Bs was discovered in parts of these animals. We analyzed the distribution of Bs among the worms of the laboratory cultures during long-term cultivation, the transmission rates of Bs in the progeny obtained from crosses of worms with different numbers of Bs, and from self-fertilized isolated worms. The DNA content of the Bs in M. mirumnovem was analyzed with the chromosomal in situ suppression (CISS) hybridization of microdissected DNA probes derived from A chromosomes (As). Bs mainly consisted of repetitive DNA. The cytogenetic analysis also revealed the divergence and high variation in large metacentric chromosomes (LMs) containing numerous regions enriched for repeats. The possible mechanisms of the appearance and evolution of Bs and LMs in species of the Macrostomum genus were also discussed.

Mates Matter: Gametophyte Kinship Recognition and Inbreeding in the Giant Kelp, Macrocystis pyrifera (Laminariales, Phaeophyceae).

Inbreeding, the mating between genetically related individuals, often results in reduced survival and fecundity of offspring, relative to outcrossing. Yet, high inbreeding rates are commonly observed in seaweeds, suggesting compensatory reproductive traits may affect the costs and benefits of the mating system. We experimentally manipulated inbreeding levels in controlled crossing experiments, using gametophytes from 19 populations of Macrocystis pyrifera along its Eastern Pacific coastal distribution (EPC). The objective was to investigate the effects of male-female kinship on female fecundity and fertility, to estimate inbreeding depression in the F1 progeny, and to assess the variability of these effects among different regions and habitats of the EPC. Results revealed that the presence and kinship of males had a significant effect on fecundity and fertility of female gametophytes. Females left alone or in the presence of sibling males express the highest gametophyte size, number, and size of oogonia, suggesting they were able to sense the presence and the identity of their mates before gamete contact. The opposite trend was observed for the production of embryos per female gametes, indicating higher costs of selfing and parthenogenesis than outcrossing on fertility. However, the increased fecundity compensated for the reduced fertility, leading to a stable overall reproductive output. Inbreeding also affected morphological traits of juvenile sporophytes, but not their heatwave tolerance. The male-female kinship effect was stronger in high-latitude populations, suggesting that females from low-latitude marginal populations might have evolved to mate with any male gamete to guarantee reproductive success.

In search of the real Pseudomallada prasinus (Neuroptera, Chrysopidae).

Three sympatric morphs of Pseudomallada prasinus (Burmeister, 1839) were hybridized in search of reproductively     separated species. In addition, 26 morphological and biological traits were recorded for living and preserved specimens of the three morphotypes.                                                                                                         Cross-breeding experiments showed that the prasinoid morph "marianus" is a different species from either the "greenhead" or "sulfurhead" morphs. All three are morphologically and biologically distinct. "Greenhead" and "sulfurhead" are small to medium sized and deposit eggs singly, without obligatory diapause in the second instar. In most specimens of these two smaller "prasinus" morphs there is a red or brown suture below the antennae, which can fade with age or preservation. P. "marianus" is a large species, depositing bundled eggs, with an obligatory diapause in about half of the L2. In none of the collected or reared P. "marianus" was a red or brown suture below the eyes observed. The forewing sizes of the type specimens of Chrysopa prasina Burmeister, 1839, C. coerulea Brauer, 1851, and C. marianus Navás, 1915 differ significantly from those of C. aspersa Wesmael, 1841 and other, later synonymized type specimens such as C. sachalinensis Matsumura, 1911, C. burri Navás, 1914, C. caucasica Navás, 1914, or C. vernalis Navás, 1926. This strongly suggests that the "marianus" morph is the real P. prasinus and the "greenhead" and "sulfurhead" morphs correspond to P. aspersus or one of the later synonymized species with smaller wing size.Pseudomallada marianus (Navás, 1905) is confirmed as a synonym of P. prasinus, depositing bundled eggs, whereas smaller prasinoid morphs, depositing single eggs, are not P. prasinus-and are morphologically distinct from P. abdominalis (Brauer, 1856). Pseudomallada aspersus (Wesmael, 1841) is a valid species, but at this point it is not possible to assign it to one of the prasinoid morphs because most of the live color traits are not discernible in old type specimens. A diagnostic description of the "real" P. prasinus can separate almost all P. prasinus specimens, even in museum collections, from P. aspersus (likely to be the "greenhead" morph) and the Mediterranean "sulfurhead".

Arousal from Tonic Immobility by Vibration Stimulus.

Tonic immobility (TI) is an effective anti-predator strategy. However, long immobility status on the ground increases the risk of being eaten by predators, and thus insects must rouse themselves when appropriate stimulation is provided. Here, the strength of vibration causing arousal from the state of TI was examined in strains artificially selected for longer duration of TI (L-strains: long sleeper) in a beetle. We provided different strengths of vibration stimuli to the long sleepers in Tribolium castaneum. Although immobilized beetles were never awakened by the stimuli from 0.01 to 0.12 mm in amplitude, almost of the beetles were aroused from immobilized status by the stimulus at 0.21 mm. There was a difference in sensitivity of individuals when the stimuli of 0.14 mm and 0.18 mm were provided. F2 individuals were also bred by crossing experiments of the strains selected for shorter and longer duration of TI. The arousal sensitivity to vibration was well separated in the F2 individuals. A positive relationship was observed between the duration of TI and the vibration amplitude, suggesting that immobilized beetles are difficult to arouse from a deep sleep, while light sleepers are easily aroused by even small vibrations. The results indicate a genetic basis for sensitivity to arousal from TI.

Anther Rubbing, a New Mechanism That Actively Promotes Selfing in Plants.

Self-fertilization has recurrently evolved in plants, involving different strategies and traits and often loss of attractive functions, collectively known as the selfing syndrome. However, few traits that actively promote self-fertilization have been described. Here we describe a novel mechanism promoting self-fertilization in the Brassicaceae species Erysimum incanum. This mechanism, which we called "anther rubbing," consists of autonomous, repeated, and coordinated movements of the stamens over the stigma during flower opening. We have documented anther rubbing by time-lapse videos and experimentally show that it causes self-pollen deposition on stigmas and is sufficient to achieve maximal reproductive output in E. incanum. We predict that these movements should occur in species with limited inbreeding depression, and indeed we find that inbreeding depression in seed production is negligible in this species. While many studies have documented complex floral traits that promote outcrossing, the occurrence of anther rubbing demonstrates that plants can evolve elaborate and underappreciated adaptations to promote self-fertilization.

Further insight into reproductive incompatibility between putative cryptic species of the Bemisia tabaci whitefly complex.

The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), with its global distribution and extensive genetic diversity, is now known to be a complex of over 35 cryptic species. However, a satisfactory resolution of the systematics of this species complex is yet to be achieved. Here, we designed experiments to examine reproductive compatibility among species with different levels of mitochondrial cytochrome oxidase I (mtCOI) divergence. The data show that putative species with mtCOI divergence of >8% between them consistently exhibited complete reproductive isolation. However, two of the putative species, Asia II 9 and Asia II 3, with mtCOI divergence of 4.47% between them, exhibited near complete reproductive compatibility in one direction of their cross, and partial reproductive compatibility in the other direction. Together with some recent reports on this topic from the literature, our data indicates that, while divergence in the mtCOI sequences provides a valid molecular marker for species delimitation in most clades, more genetic markers and more sophisticated molecular phylogeny will be required to achieve adequate delimitation of all species in this whitefly complex. While many attempts have been made to examine the reproductive compatibility among genetic groups of the B. tabaci complex, our study represents the first effort to conduct crossing experiments with putative species that were chosen with considerations of their genetic divergence. In light of the new data, we discuss the best strategy and protocols to conduct further molecular phylogenetic analysis and crossing trials, in order to reveal the overall pattern of reproductive incompatibility among species of this whitefly complex.

Karyotypic variation and geographic distribution of Anopheles campestris-like (Diptera: Culicidae) in Thailand

Seventy-one isolines of Anopheles campestris-like were established from wild-caught females collected from human-biting and animal-biting traps at 12 locations in Thailand. All isolines had an average branch summation of seta 2-VI pupal skins ranging from 20.3-30.0 branches, which is in the range of An. campestris (17-58 branches). They showed three different karyotypes based on the amount of extra heterochromatin in the sex chromosomes, namely Forms B (X2, Y2), E (X1, X2, X3, Y5) and a new karyotypic Form F (X2, X3, Y6). Form B has been found only in Chaing Mai and Kamphaeng Phet populations, while Forms E and F are widely distributed throughout the species range. Genetic crosses between the 12 isolines, which were arbitrarily selected as representatives of An. campestris-like Forms B, E and F, revealed genetic compatibility that provided viable progeny through F2 generations, suggesting a conspecific nature of these karyotypic forms. These results are supported by the very low intraspecies variation (genetic distance < 0.005) of ITS2, COI and COII from genomic DNA of the three karyotypic forms.

Partial self-incompatibility and inbreeding depression in a native tree species of La Réunion (Indian Ocean).

We investigated the reproductive system of the threatened taxon Dombeya acutangula ssp. acutangula Cav. (Sterculiaceae), an endemic tree of the Mascarene archipelago (Indian Ocean). A controlled crossing experiment was performed in two natural populations located in the remnants of the low-elevation dry forest on the island of La Réunion. Active pollination, probably mainly by insects, was necessary for reproduction in this species. Individuals varied in their degree of self-sterility from 0 to 100%. Outcrossing between nearby individuals produced lower seed set than did crosses between more distant individuals within one of the two tested populations. The variation in reproductive success on selfing and in the different types of crosses could result from inbreeding depression causing embryo death, and we provide evidence that progenies from selfing have lower seed size and quality. However, for inbreeding depression to account for the dramatic variation in seed set found in our crossing experiment, the distribution of genetic load and number of lethal factors required appear unrealistic. We favour an alternative interpretation, that D. acutangula possesses an incompatibility system similar to that found in other Sterculiaceae species such as Theobroma cacao L. Such an incompatibility system allows a certain amount of selfing, and different individuals vary in their degree of self-incompatibility. The low success of crosses among close neighbours in one population suggests that there was spatial structure for incompatibility alleles in that population. This could partly explain the decline of the species in fragmented and disturbed habitats, since relatedness at incompatibility loci may increase in small or isolated population and thus reduce mate availability.