Fighting for mates: the importance of individual size in mating contests in rocky shore littorinids

Studies of mating contests have reported how traits (e.g. body size) related to resource holding potential (RHP) and strategies to assess RHP and resource value influence contest outcome in many taxa but are rare in the Gastropoda. The influence of male size (as an index of RHP) and female size (as a measure of resource value) on contest outcome were investigated in two littorinid snails, Echinolittorina malaccana and E. radiata, in Hong Kong during May－June 2013. In these snails, contests between males take the form of a 'challenger' attempting to take over the copulation position occupied by a 'defender'. Both challengers and defenders were, generally, smaller than the females in both species. In both species, the larger the challenger relative to the defender, the more likely he would replace the defender in the copulation position. The challengers were, however, more successful in E. radiata, as they generally challenged defenders that were smaller than themselves, suggesting an ability to detect rival size before entering into a contest in this species. When sizes of the contestants were similar, defenders were more likely to win contests in E. malaccana but not in E. radiata. Evidence for pure self-assessment of RHP and the ability to assess resource value in challengers was found in E. malaccana. Different fighting strategies appear to have evolved in these congeneric marine snail species and decisions based on male and female sizes play an important role in determining male reproductive success

Gene expression of endangered coral (Orbicella spp.) in flower garden banks National Marine Sanctuary after Hurricane Harvey

About 190 km south of the Texas–Louisiana border, the East and West Flower Garden Banks (FGB) have maintained > 50% coral cover with infrequent and minor incidents of disease or bleaching since monitoring began in the 1970s. However, a mortality event, affecting 5.6 ha (2.6% of the area) of the East FGB, occurred in late July 2016 and coincided with storm-generated freshwater runoff extending offshore and over the reef system. To capture the immediate effects of storm-driven freshwater runoff on coral and symbiont physiology, we leveraged the heavy rainfall associated with Hurricane Harvey in late August 2017 by sampling FGB corals at two time points: September 2017, when surface water salinity was reduced (∼34 ppt); and 1 month later when salinity had returned to typical levels (∼36 ppt in October 2017). Tissue samples (N = 47) collected midday were immediately preserved for gene expression profiling from two congeneric coral species (Orbicella faveolata and Orbicella franksi) from the East and West FGB to determine the physiological consequences of storm-derived runoff. In the coral, differences between host species and sampling time points accounted for the majority of differentially expressed genes. Gene ontology enrichment for genes differentially expressed immediately after Hurricane Harvey indicated increases in cellular oxidative stress responses. Although tissue loss was not observed on FGB reefs following Hurricane Harvey, our results suggest that poor water quality following this storm caused FGB corals to experience sub-lethal stress. We also found dramatic expression differences across sampling time points in the coral’s algal symbiont, Breviolum minutum. Some of these differentially expressed genes may be involved in the symbionts’ response to changing environments, including a group of differentially expressed post-transcriptional RNA modification genes. In this study, we cannot disentangle the effects of reduced salinity from the collection time point, so these expression patterns could also be related to seasonality. These findings highlight the urgent need for continued monitoring of these reef systems to establish a baseline for gene expression of healthy corals in the FGB system across seasons, as well as the need for integrated solutions to manage stormwater runoff in the Gulf of Mexico.https://www.frontiersin.org/articles/10.3389/fmars.2019.00672/fullPublished versionPublished versio

Sampling scale can cause bias in positive assortative mating estimates: The first evidence in two intertidal snails

Assortative mating in the wild is commonly estimated by correlating between traits in mating pairs (e.g. size of males and females). Unfortunately such an approach may suffer from considerable sampling bias when the distribution of different expressions of a trait in the wild is non-random; for example, when segregation of different size classes of individuals occur in different microhabitats or areas. Consequently, any observed trait correlation in the wild can be an artifact of pooling heterogeneous samples of mating pairs from different microhabitats or areas rather than true non-random matings. This bias in estimating trait correlations due to sampling scale is termed the scale-of-choice effect (SCE). Here we use two intertidal littorinid species from Hong Kong to show how the SCE can bias size-assortative mating estimates from mating pairs captured in the wild, empirically demonstrating the influence of this effect on measures of positive assortative mating. This finding cautions that studies that have overlooked SCE may have misinterpreted the magnitude and the cause of assortative mating, and we provide a new analytical approach to protect against this potential bias in future studies

Hawking-Unruh effect and the entanglement of two-mode squeezed states in Riemannian spacetime

We consider the system of free scalar field, which is assumed to be a two-mode squeezed state from an inertial point of view. This setting allows the use of entanglement measure for continuous variables, which can be applied to discuss free and bound entanglement from the point of view from non-inertial observer.Comment: Phys. Lett. A, accepted for publicatio

Effects of dietary baker’s yeast extract on the growth, blood indices and histology of Nile tilapia ( Oreochromis niloticus L.) fingerlings

Nile tilapia, Oreochromis niloticus (average initial weight, 5.91 ± 0.04 g), were fed four isonitrogenous and isolipidic diets for 84 days. The diets contained four levels of yeast extract (CW‐I) rich in nucleotides and β‐glucan: 0 (control), 5, 10 and 15 g/kg diet. Weight gain increased linearly, whereas the feed conversion ratio decreased linearly with increasing levels of yeast extract. The diet containing 15 g/kg yeast extract resulted in significantly better (p 0.05) differences were found in dry matter, protein, lipid or ash contents or in haematocrit, haemoglobin or total protein contents among the treatment groups. Blood sample profiles showed an increase in white and red blood cells in fish fed 15 g/kg yeast extract in comparison with the other treatment groups. The fish fed the diets with 10 and 15 g/kg yeast extract had significantly higher albumin and globulin levels than the control group, whereas decreased levels of cholesterol and triglycerides, aspartate aminotransferase and alanine aminotransferase were noted in fish fed the diet with 15 g/kg yeast extract. Histological analysis of the liver and intestine in fish fed the control diet showed a slightly abnormal structure in these organs. Only in fish fed diets supplemented with the highest amount of yeast extract was the structure of the hepatocytes and villi almost unchanged, which indicated that the yeast nucleotides could improve hepatic function and promote liver and gut restoration

The causal relationship between sexual selection and sexual size dimorphism in marine gastropods

Sexual size dimorphism is widespread among dioecious species, but its underlying driving forces are often complex. A review of sexual size dimorphism in marine gastropods revealed two common patterns: first, sexual size dimorphism, with females being larger than males, and, second, females being larger than males in mating pairs. Both patterns suggest sexual selection and sexual size dimorphism are causally related. To test this hypothesis, we investigated, first, mechanisms driving sexual selection on size in three congeneric marine gastropods with different degrees of sexual size dimorphism, and, second, the correlation between male/female sexual selection and sexual size dimorphism across several marine gastropod species. Male mate choice via mucus trail following (as evidence of sexual selection) was found during the mating process in all three congeneric species, even though not all species showed sexual size dimorphism. There was also a significant and strong negative correlation between female sexual selection and sexual size dimorphism across 16 cases from seven marine gastropod species. These results suggest that sexual selection does not drive sexual size dimorphism. There was, however, evidence of males utilizing a similar mechanism to choose mates (i.e. selecting a female slightly larger than their own size) which may be widespread among gastropods, and, in tandem with sexual size dimorphism varying between species, provides a plausible explanation of the mating patterns observed in marine gastropods

Modified spontaneous symmetry breaking pattern by brane-bulk interaction terms

We show how translational invariance can be broken by the vacuum that drives the spontaneous symmetry breaking of extra-dimensional extensions of the Standard Model, when delta-like interactions between brane and bulk scalar fields are present. We explicitly build some examples of vacuum configurations, which induce the spontaneous symmetry breaking, and have non trivial profile in the extra coordinate.Comment: 13 pages, two figure

Direct composition profiling in III-V nanostructures by cross-sectional STM

Using cross-sectional STM we have studied the local composition in III–V nanostructures such as GaAs/InGaAs quantum wells, InGaNAs/InP quantum wells and quantum dots, and InAs/GaAs self-assembled quantum dots. We are able to determine the local composition by either simply counting the constituent atoms, measuring the local lattice constant or measuring the relaxation of the cleaved surface due to the elastic field of the buried strained nanostructures

Adiabatic response for Lindblad dynamics

We study the adiabatic response of open systems governed by Lindblad evolutions. In such systems, there is an ambiguity in the assignment of observables to fluxes (rates) such as velocities and currents. For the appropriate notion of flux, the formulas for the transport coefficients are simple and explicit and are governed by the parallel transport on the manifold of instantaneous stationary states. Among our results we show that the response coefficients of open systems, whose stationary states are projections, is given by the adiabatic curvature.Comment: 33 pages, 4 figures, accepted versio

HPV-18 transformed cells fail to arrest in G1 in response to quercetin treatment

Previous work with primary human keratinocytes demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (Pteridium aquilinum), arrested cells in G1 with concomitant elevation of the cyclin-dependent kinase inhibitor (cdki) p27Kip1. Expression of the human papillomavirus type 16 (HPV-16) E6 and E7 oncoproteins, under transcriptional control of a heterologous promoter, in transformed keratinocytes failed to abrogate this arrest [Beniston, R., Campo, M.S., 2003. Quercetin elevates p27(Kip1) and arrests both primary and HPV-16 E6/E7 transformed human keratinocytes in G1. Oncogene 22, 5504–5514]. Given the link between papillomavirus infection, bracken fern in the diet and cancer of the oesophagus in humans, we wished to investigate further whether cells transformed by the whole genome of HPV-16 or HPV-18, with E6 and E7 under the transcriptional control of their respective homologous promoters, would be similarly arrested in G1 by quercetin. In agreement with earlier work, quercetin arrested HPV-16 transformed cells in G1 with an increase in the cyclin-dependent kinase inhibitor p27Kip1. However, HPV-18 transformed cells did not arrest after quercetin treatment. The failure of HPV-18 transformed cells to arrest in G1 was linked to the up-regulation of the HPV-18 long control region (LCR) by quercetin, maintaining high expression of the viral transforming proteins. Transcriptional up-regulation of the HPV-18 LCR was mediated by a “quercetin responsive element” homologous to the one identified previously in the bovine papillomavirus type 4 (BPV-4) LCR