Innate responses to male sexual harassment in female mosquitofish

Male mosquitofish are very persistent in their sexual activity and harass any female they encounter. Gravid females pay a large tribute to this intense male sexual activity in terms of reduced foraging efficiency. Previous observations have demonstrated that gravid females, when chased by a male, dilute male harassment by moving closer to other females to form shoals. They also approach other males to promote male competition, and when males differ in size, they preferentially target large males, whose harassment is less intense. In this study, we tested whether the modulation of females’ social preferences in response to male harassment is innate or learned. We tested social preference in three groups of females that differed in experience of sexual harassment and in the factors affecting it. Females of the first group were reared without any sexual experience, and pregnancy was induced through artificial insemination. The second group was composed of naive females kept singly with a male; these females experienced sexual harassment but were prevented from experiencing the effects of male–male competition and shoaling on the amount of male sexual harassment. In the third group (controls), females were reared in multi-male, multi-female groups and could experience the modulating effects of social interactions on sexual harassment. When exposed to a harassing male, females of the three groups immediately reduced their distance from another female, approached a group of males or moved toward the larger of two available males. Moreover, the results for these three groups of females were similar to those obtained in wild-caught females that were tested in the same three tests in a previous study (Dadda et al. An. Behav., 70:463–471, 2005). This suggests that the strategies adopted by females in response to male sexual harassment do not need to be learned through specific experience of the social contexts.     

Evaluation and classification of severity for 176 genes on an expanded carrier screening panel

Background

Disease severity is important when considering genes for inclusion on reproductive expanded carrier screening (ECS) panels. We applied a validated and previously published algorithm that classifies diseases into four severity categories (mild, moderate, severe, and profound) to 176 genes screened by ECS. Disease traits defining severity categories in the algorithm were then mapped to four severity-related ECS panel design criteria cited by the American College of Obstetricians and Gynecologists (ACOG).

Methods

Eight genetic counselors (GCs) and four medical geneticists (MDs) applied the severity algorithm to subsets of 176 genes. MDs and GCs then determined by group consensus how each of these disease traits mapped to ACOG severity criteria, enabling determination of the number of ACOG severity criteria met by each gene.

Results

Upon consensus GC and MD application of the severity algorithm, 68 (39%) genes were classified as profound, 71 (40%) as severe, 36 (20%) as moderate, and one (1%) as mild. After mapping of disease traits to ACOG severity criteria, 170 out of 176 genes (96.6%) were found to meet at least one of the four criteria, 129 genes (73.3%) met at least two, 73 genes (41.5%) met at least three, and 17 genes (9.7%) met all four.

Conclusion

This study classified the severity of a large set of Mendelian genes by collaborative clinical expert application of a trait-based algorithm. Further, it operationalized difficult to interpret ACOG severity criteria via mapping of disease traits, thereby promoting consistency of ACOG criteria interpretation.

     

Nestling rearing is antioxidant demanding in female barn swallows (Hirundo rustica)

Reproduction is a demanding activity, since organisms must produce and, in some cases, protect and provision their progeny. Hence, a central tenet of life-history theory predicts that parents have to trade parental care against body maintenance. One physiological cost thought to be particularly important as a modulator of such trade-offs is oxidative stress. However, evidence in favour of the hypothesis of an oxidative cost of reproduction is contradictory. In this study, we manipulated the brood size of wild barn swallows Hirundo rustica soon after hatching of their nestlings to test whether an increase in nestling rearing effort translates into an increased oxidative damage and a decreased antioxidant protection at the end of the nestling rearing period. We found that, while plasma oxidative damage was unaffected by brood size enlargement, females rearing enlarged broods showed a decrease in plasma non-enzymatic antioxidants during the nestling rearing period. This was not the case among females rearing reduced broods and among males assigned to either treatment. Moreover, individuals with higher plasma oxidative damage soon after the brood size manipulation had lower plasma non-enzymatic antioxidants at the end of the nestling rearing period, suggesting that non-enzymatic antioxidants were depleted to buffer the negative effects of high oxidative damage. Our findings point to antioxidant depletion as a potential mechanism mediating the cost of reproduction among female birds.     

Methanesulphonic acid (MSA) stratigraphy from a Talos Dome ice core as a tool in depicting sea ice changes and southern atmospheric circulation over the previous 140 years

Firn core methanesulphonic acid (MSA) stratigraphy from Talos Dome (East Antarctica) was compared with anomalies of the satellite-measured sea ice extent (1973–1995) in the Ross Sea and Wilkes Land oceanic sector. In spite of the sparseness of sea ice data, the MSA maxima fit with many positive sea ice anomalies in the Ross Sea. This evidence suggests that marine biogenic activity enhanced by large sea ice cover is an important, but not exclusive, factor in controlling MSA concentration in snow precipitation at Talos Dome. Other than source intensity, differences in regional atmospheric transport mechanisms affect the arrival of MSA-rich aerosol at Talos Dome. To clarify the role of transport processes in bringing biogenic aerosol to Talos Dome, a spectral analysis was applied to the MSA, SOI (South Oscillation Index), and SAM (Southern Annular Mode) record. Synchronicity or phase shift between the chemical signature and atmospheric circulation modes were tested. The variations in the MSA profile have a periodicity of 6.9, 4.9, 3.5, and 2.9 years. The 6.9 and 2.9 year periodicities show a strong positive correlation and are synchronous with corresponding SOI periodicity. This variability could be related to an increase in MSA source intensity (by dimethylsulphide from phytoplanktonic activity) linked to the sea ice extent in the Ross Sea area, but also to an increased strength in transport processes. Both of these factors are correlated with La Niña events (SOI positive values). Furthermore, SAM positive values are related to an increased sea ice extent in the Ross Sea sector and show two main periodicities 3.3 and 3.8 years. These periodicities determine the MSA variability at 3.5 years. However, the effect of intensification of the polar vortex and the consequent reduction in transport process intensity, which reduce the delivery of air masses enriched in MSA from oceanic areas to Talos Dome, make the effect of the SAM on the MSA concentration at Talos Dome less active than the SOI. In this way, snow deposition at the Talos Dome records larger MSA concentration by the combined effects of increased source emissions and more efficient transport processes. The MSA record from Talos Dome can therefore be considered a reliable proxy of sea ice extent when the effect of changes in transport processes in this region of Antarctica is considered. Over the previous 140 years, these conditions occur with a periodicity of 6.9 years.     

Anguilliform larvae collected off North Carolina

The distinctive larval stage of eels (leptocephalus) facilitates dispersal through prolonged life in the open ocean. Leptocephali are abundant and diverse off North Carolina, yet data on distributions and biology are lacking. The water column (from surface to 1,293 m) was sampled in or near the Gulf Stream off Cape Hatteras, Cape Lookout, and Cape Fear, North Carolina during summer through fall of 1999–2005, and leptocephali were collected by neuston net, plankton net, Tucker trawl, and dip net. Additional samples were collected nearly monthly from a transect across southern Onslow Bay, North Carolina (from surface to 91 m) from April 2000 to December 2001 by bongo and neuston nets, Methot frame trawl, and Tucker trawl. Overall, 584 tows were completed, and 224 of these yielded larval eels. The 1,295 eel leptocephali collected (combining all methods and areas) represented at least 63 species (nine families). Thirteen species were not known previously from the area. Dominant families for all areas were Congridae (44% of individuals, 11 species), Ophichthidae (30% of individuals, 27 species), and Muraenidae (22% of individuals, ten species). Nine taxa accounted for 70% of the overall leptocephalus catches (in order of decreasing abundance): Paraconger caudilimbatus (Poey), Gymnothorax ocellatus Agassiz complex, Ariosoma balearicum (Delaroche), Ophichthus gomesii (Castelnau), Callechelys muraena Jordan and Evermann, Letharchus aliculatus McCosker, Rhynchoconger flavus (Goode and Bean), Ophichthus cruentifer (Goode and Bean), Rhynchoconger gracilior (Ginsburg). The top three species represented 52% of the total eel larvae collected. Most leptocephali were collected at night (79%) and at depths > 45 m. Eighty percent of the eels collected in discrete depth Tucker trawls at night ranged from mean depths of 59–353 m. A substantial number (38% of discrete depth sample total) of larval eels were also collected at the surface (neuston net) at night. Daytime leptocephalus distributions were less clear partly due to low catches and lower Tucker trawl sampling effort. While net avoidance may account for some of the low daytime catches, an alternative explanation is that many species of larval eels occur during the day at depths > 350 m. Larvae of 21 taxa of typically shallow water eels were collected at depths > 350 m, but additional discrete depth diel sampling is needed to resolve leptocephalus vertical distributions. The North Carolina adult eel fauna (estuary to at least 2,000 m) consists of 51 species, 41% of which were represented in these collections. Many species of leptocephali collected are not yet known to have juveniles or adults established in the South Atlantic Bight or north of Cape Hatteras. Despite Gulf Stream transport and a prolonged larval stage, many of these eel leptocephali may not contribute to their respective populations.     

Size,spatial, and bathymetrical distribution of the ascidian Halocynthia papillosa in Mediterranean coastal bottoms: benthic–pelagic coupling implications

Benthic suspension feeders are abundant in Mediterranean coastal environments, though most of them are threatened due to overexploitation, climate change impacts, and unregulated diving or fishing practices. Little is known about most of the coastal communities in terms of large-scale distribution and realistic benthic–pelagic coupling implications, which are keys to understand and manage those threatened ecosystems. The active suspension feeder Halocynthia papillosa (one of the most common ascidian species of the Mediterranean Sea) was selected as a model organism to help to understand the ecological role in benthic–pelagic coupling processes and its importance as a carbon sink (an essential ecosystem service). The spatial and bathymetrical distribution of this organism has been studied using remotely operated vehicle video transects. The species was distributed throughout the study area, with a maximum density of 4 specimens m^?2. The highest abundances and the biggest sizes were observed on the range of 20–50 m depth. The role as carbon and nitrogen sink of this suspension feeder has been quantified coupling distribution data with existing in situ studies of feeding and respiration. Along the 1.24 ha of the study area, H. papillosa yearly ingested 519.4 g C and 31.4 g N and retained 20.2 g C. As long as the physiological data are known, this new methodology could be very useful in assessing bentho–pelagic links and the capacity of being C and N sinks of a wide range of species. This new approach may be essential for the future management of benthic communities.