The effect of size and cheliped autotomy on sexual competition between males of the mud crab <Emphasis Type="Italic">Cyrtograpsus angulatus</Emphasis> Dana

Size advantage in male–male competition over mates, combined with male preference over large females, is a common feature that can drive to size assortative mating and, eventually, sexual selection. In crabs, appendage autotomy can affect assortative mating and opportunity for sexual selection by affecting size advantage in mating contests. In this work, we evaluate the effect of size and appendage autotomy in generating assortative mating in the mud crab Cyrtograpsus angulatus. Field observations of guarding pairs in two different populations show a positive correlation between carapace width of males and females in both the populations. In one of the populations, incidence of appendage autotomy was low and the variability in the size of reproductive males was lower than the variability in the size of randomly collected males (i.e. only larger males were successful in getting a female), whereas there was no differences in the other population (i.e. most male sizes were successful) where the incidence of appendage autotomy was very high, indicating that the importance of size is higher when the incidence of autotomy is low. In this context, experiments (in both populations) show that, in contests for a female, larger males outcompete smaller ones only when they had intact appendages. When males had missing chelipeds, winning or loosing against smaller males was random. This may lead to a decrease in the importance of male size in populations with high incidence of cheliped autotomy, affecting assortative mating and opportunity for selection and, thus, affecting selective pressures.     

Knowledge,attitudes and practices of occupational risks in Colombian taxi drivers

Objective. The objective of this study was to learn about the health and safety strategies in a sample of taxi drivers in Bucaramanga, Colombia. Methods. A cross-sectional study was conducted among 138 taxi drivers. A survey was used to identify the socio-demographic and working characteristics, knowledge, attitudes and practices according to their occupational risk. Results. Eighty-five percent of the workers labored 9–15?h/day. Of those who suffered accidents, 27% were not affiliated to an occupational risk administrator (p = 0.028). Of the workers who had a work-related accident, 58% considered that the use of a cell phone while driving would not always reduce their attention, 50% always used their seat belt and 7% took active breaks and wore their seat belt (p = 0.01). Conclusions. Within this group of taxi drivers, having or believing to possess knowledge regarding an occupational risk did not ensure that they had a safe attitude or safe working practices.     

Onset of symbiosis and distribution patterns of symbiotic dinoflagellates in the larvae of scleractinian corals

The establishment of symbiosis in early developmental stages is important for reef-building corals because of the need for photosynthetically derived nutrition. Corals spawn eggs and sperm, or brood planula larvae and shed them into the water. Some coral eggs or planulae directly inherit symbiotic dinoflagellates (Symbiodinium spp.) from their parents, while others acquire them at each generation. In most species examined to date, the larvae without dinoflagellates (aposymbiotic larvae) can acquire symbionts during the larval stage, but little is known regarding the timing and detailed process of the onset of symbiosis. We examined larval uptake of symbiotic dinoflagellates in nine species of scleractinian corals, the onset of symbiosis through the early larval stages, and the distribution pattern of symbionts within the larval host, while living and with histology, of two acroporid corals under laboratory conditions. The larvae acquired symbiotic dinoflagellates during the planktonic phase in all corals examined which included Acropora digitifera, A. florida, A. intermedia, A. tenuis, Isopora palifera, Favia pallida, F. lizardensis, Pseudosiderastrea tayamai, and Ctenactis echinata. The larvae of A. digitifera and A. tenuis first acquired symbionts 6 and 5 days after fertilization, respectively. In A. digitifera larvae, this coincided with the formation of an oral pore and coelenteron. The number of symbiotic dinoflagellates increased over the experimental periods in both species. To test the hypothesis that nutrients promotes symbiotic uptake, the number of incorporated dinoflagellates was compared in the presence and absence of homogenized Artemia sp. A likelihood ratio test assuming a log-linear model indicated that Artemia sp. had a significantly positive effect on symbiont acquisition. These results suggest that the acquisition of symbiotic dinoflagellates during larval stages is in common with many coral species, and that the development of both a mouth and coelenteron play important roles in symbiont acquisition.     

Resilience thinking applied to fisheries management: perspectives for the mullet fishery in Southern-Southeastern Brazil

The mullet fishery system encompasses a complex arrange of ecological and socioeconomic factors interacting in multiple scales on the Southern-Southeastern Brazilian coast. Similarly, to other fisheries in developing countries, overfishing and poor governance have been threatening the resilience of the mullet fishery. In this paper, we explore aspects related to fisheries management from the perspective of the concept of resilience. The industrial and artisanal fishery sectors represent the different stakeholders. The main issues of concern are related to failures in the fisheries management to properly address equity in resource access and resource use sustainability among stakeholders. Asymmetry in technology and political and economic power affect food security and income generation especially for subsistence and small-scale fishing. Despite changes in rules-in-use, overfishing and conflicts between resource users are still relevant. Fishery dynamics and resource availability are greatly affected locally by forces such as pollution, urbanization, non-selective fishing, and regionally, by the El Niño Southern Oscillation (ENSO), and industrial (purse-seine) fishery. Considering the influence of ENSO on this fishery, a time span of at least 7 years to investigate this system could provide better answers to improve the management. Effective resilient fisheries should rely on three aspects. First, there should be a flexible fish allocation system based on ecosystem variability. Secondly, fish allocation should prioritize food security and poverty alleviation. Thirdly, a monitoring system should be implemented that takes into consideration ecosystem, fisheries and human dimensions to support a flexible and adaptive fisheries management, with resilient fisheries as an ultimate goal.     

Microplastic pollution on the soil and its consequences on the nitrogen cycle: a review

Environmental Science and Pollution Research - Microplastics (MPs) correspond to plastics between 0.1 μm and 5 mm in diameter, and these can be intentionally manufactured to be microscopic or...     

Trace element contents in fine particulate matter (PM<Subscript>2.5</Subscript>) in urban school microenvironments near a contaminated beach with mine tailings,Chañaral,Chile

Air quality in schools is an important public health issue because children spend a considerable part of their daily life in classrooms. Particulate size and chemical composition has been associated with negative health effects. We studied levels of trace element concentrations in fine particulate matter (PM_2.5) in indoor versus outdoor school settings from six schools in Chañaral, a coastal city with a beach severely polluted with mine tailings. Concentrations of trace elements were measured on two consecutive days during the summer and winter of 2012 and 2013 and determined using X-ray fluorescence. Source apportionment and element enrichment were measured using principal components analysis and enrichment factors. Trace elements were higher in indoor school spaces, especially in classrooms compared with outdoor environments. The most abundant elements were Na, Cl, S, Ca, Fe, K, Mn, Ti, and Si, associated with earth’s crust. Conversely, an extremely high enrichment factor was determined for Cu, Zn, Ni and Cr; heavy metals associated with systemic and carcinogenic risk effects, whose probably origin sources are industrial and mining activities. These results suggest that the main source of trace elements in PM_2.5 from these school microenvironments is a mixture of dust contaminated with mine tailings and marine aerosols. Policymakers should prioritize environmental management changes to minimize further environmental damage and its direct impact on the health of children exposed.