Long corollas as nectar barriers in <Emphasis Type="Italic">Lonicera implexa</Emphasis>: interactions between corolla tube length and nectar volume

Long corollas are a classical example of nectar barriers, because they prevent undesired visitors from consuming the reward intended for more effective pollinators. As the investment in nectar barriers increases, flower attractiveness and nectar rewards may also increase to maintain loyal visitation of most effective pollinators; and flowers may become more prone to nectar robbing. We evaluated the effect of nectar barriers (corolla tube length), two related traits (nectar volume and upper lip size) and the associated risk of nectar robbing, on the fecundity of Lonicera implexa plants from three populations differing in the abundance of its most efficient pollinator, the hummingbird hawkmoth Macroglossum stellatarum. Corolla tube length varied most among individuals within populations (45–46 % of total variance) and inflorescences within individuals (23–32 %), and showed little variation among populations (0.2–11 %). Longer corolla tubes were always associated with larger nectar volumes and larger upper lips, although the strength of the relationships varied across populations and years. Robbing frequency increased with corolla tube length, decreased with nectar volume and upper lip size, and its weak effects on fecundity were predominantly positive. Plant fecundity peaked at two different optima: long corollas with little nectar and short corollas with abundant nectar. However, the exact shape of the interaction between corolla length and nectar volume, as well as the combination of traits showing the highest fecundity, differed between populations and years. This variation could be explained by among-population differences in pollinator assemblages, and inter-annual changes in resources dedicated to reproduction. Our study shows that large nectar volumes can modulate the effect of corolla length as a nectar barrier, and that the combination of these two traits that maximises fecundity may be related to the identity of pollinators within each population.     

A conserved Pol? binding module in Ctf18-RFC is required for S-phase checkpoint activation downstream of Mec1

Defects during chromosome replication in eukaryotes activate a signaling pathway called the S-phase checkpoint, which produces a multifaceted response that preserves genome integrity at stalled DNA replication forks. Work with budding yeast showed that the ‘alternative clamp loader’ known as Ctf18-RFC acts by an unknown mechanism to activate the checkpoint kinase Rad53, which then mediates much of the checkpoint response. Here we show that budding yeast Ctf18-RFC associates with DNA polymerase epsilon, via an evolutionarily conserved ‘Pol ϵ binding module’ in Ctf18-RFC that is produced by interaction of the carboxyl terminus of Ctf18 with the Ctf8 and Dcc1 subunits. Mutations at the end of Ctf18 disrupt the integrity of the Pol ϵ binding module and block the S-phase checkpoint pathway, downstream of the Mec1 kinase that is the budding yeast orthologue of mammalian ATR. Similar defects in checkpoint activation are produced by mutations that displace Pol ϵ from the replisome. These findings indicate that the association of Ctf18-RFC with Pol ϵ at defective replication forks is a key step in activation of the S-phase checkpoint.     

An overview of malaria transmission from the perspective of Amazon Anopheles vectors

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.     

Modelling the niche for a marine vertebrate: a case study incorporating behavioural plasticity,proximate threats and climate change

The integration of satellite telemetry, remotely sensed environmental data, and habitat/environmental modelling has provided for a growing understanding of spatial and temporal ecology of species of conservation concern. The Republic of Cape Verde comprises the only substantial rookery for the loggerhead turtle Caretta caretta in the eastern Atlantic. A size related dichotomy in adult foraging patterns has previously been revealed for adult sea turtles from this population with a proportion of adults foraging neritically, whilst the majority forage oceanically. Here we describe observed habitat use and employ ecological niche modelling to identify suitable foraging habitats for animals utilising these two distinct behavioural strategies. We also investigate how these predicted habitat niches may alter under the influence of climate change induced oceanic temperature rises. We further contextualise our niche models with fisheries catch data and knowledge of fisheries ‘hotspots’ to infer threat from fisheries interaction to this population, for animals employing both strategies. Our analysis revealed repeated use of coincident oceanic habitat, over multiple seasons, by all smaller loggerhead turtles, whilst larger neritic foraging turtles occupied continental shelf waters. Modelled habitat niches were spatially distinct, and under the influence of predicted sea surface temperature rises, there was further spatial divergence of suitable habitats. Analysis of fisheries catch data highlighted that the observed and modelled habitats for oceanic and neritic loggerhead turtles could extensively interact with intensive fisheries activity within oceanic and continental shelf waters of northwest Africa. We suggest that the development and enforcement of sustainable management strategies, specifically multi‐national fisheries policy, may begin to address some of these issues; however, these must be flexible and adaptive to accommodate potential range shift for this species.