Tough as a rock-boring urchin: adult Echinometra sp. EE from the Red Sea show high resistance to ocean acidification over long-term exposures

Ocean acidification, a process caused by the continuous rise of atmospheric CO₂ levels, is expected to have a profound impact on marine invertebrates. Findings of the numerous studies conducted in this field indicate high variability in species responses to future ocean conditions. This study aimed at understanding the effects of long-term exposure to elevated pCO₂ conditions on the performance of adult Echinometra sp. EE from the Gulf of Aqaba (Red Sea). During an 11-month incubation under high pCO₂ (1,433 μatm, pH_NBS 7.7) and control (435 μatm, pH_NBS 8.1) conditions, we examined the urchins’ somatic and gonadal growth, gametogenesis and skeletal microstructure. Somatic and gonadal growths were exhibited with no significant differences between the treatments. In addition, all urchins in the experiment completed a full reproductive cycle, typical of natural populations, with no detectable impact of increased pCO₂ on the timing, duration or progression of the cycle. Furthermore, scanning electron microscopy imaging of urchin tests and spines revealed no signs of the usual observed effects of acidosis, such as skeletal dissolution, widened stereom pores or non-smoothed structures. Our results, which yielded no significant impact of the high pCO₂ treatment on any of the examined processes in the urchins studied, suggest high resistance of adult Echinometra sp. EE to near future ocean acidification conditions. With respect to other findings in this area, the outcome of this study provides an example of the complicated and diverse responses of echinoids to the predicted environmental changes.     

Dispersal behaviour and colony structure in a colonial spider

Group living in spiders is characterised by two principle modes, the cooperative social mode and the colonial non-cooperative mode. Kin-relationships due to reduced dispersal determine population genetic structure in social spiders, but the dispersal mechanisms underlying group structure remain poorly understood in colonial spiders. Assuming similar ecological benefits of group living, we address the question whether reduced dispersal shapes population structure in a colonial spider, Cyrtophora citricola (Araneidae). We analysed dispersal by studying settling decisions under semi-natural conditions in experimental trees with and without colonies, and in natural populations, we estimated dispersal and colony structure using population genetic analyses. The propensity to disperse decreased with increasing age in experimental colonies. Adult females did not disperse in the experiment. Sub-adult female spiders preferred trees with a colony to trees without a colony. Dispersal in third instar juveniles was influenced significantly by wind but not by the presence of a colony. Thus, we showed that being in a colony did not inhibit juvenile dispersal, but pre-mating females were philopatric. Genetic differentiation among colonies in natural populations was heterogeneous, colonies being either little or highly differentiated. The heterogeneous structure is likely caused by colony founding by one or a few females followed by dispersal among perennial colonies. Gene flow, however, was slightly male-biased. The experimental and indirect, genetic approaches combined showed that dispersal and the breeding system of C. citricola resemble that of solitary spiders, with juvenile dispersal occurring in both sexes, while the colonial distribution is maintained by female philopatry.     

Cooperative breeding increases reproductive success in the social spider <Emphasis Type="Italic">Stegodyphus dumicola</Emphasis> (Araneae,Eresidae)

Sociality in some birds, mammals, and social insects was suggested to have evolved through the lengthening and extension of parental care behaviors to nondirect descendents. In these systems, group members care for young cooperatively and, thus, increase the reproductive success of the breeders and fitness of the young. Parental care behaviors, such as regurgitation feeding and matriphagy (consumption of the mother), occur in several subsocial and social spiders. However, it is not known whether females in a colony cooperate in caring for the young of other females and whether such cooperative care improves reproductive success. To answer this question, we created experimental colonies of the social spider Stegodyphus dumicola (Araneae, Eresidae), allowing only one female in a group to produce young, simulating reproductive skew occurring in nests in nature. In this paper, we show for the first time that females of S. dumicola cooperate in providing regurgitated food for young of other females and are even eaten by those young. Young raised by a group of females were larger and had greater survival than young raised only by their mother. Thus, fitness benefits from raising broods cooperatively may have favored the evolution of sociality in spiders.     

The use of imaging technology in the assessment of the fetal inflammatory response syndrome—imaging of the fetal thymus

The fetal inflammatory response syndrome (FIRS) describes a state of extensive fetal multi organ involvement during chorioamnionitis, and is associated with grave implications on perinatal outcome. The syndrome has been linked to the preterm parturition syndrome and is associated with inflammation/infection processes in most of the fetal organs. The fetal thymus, a major organ in the developing immune system involutes during severe neonatal disease and has been shown to be smaller in fetuses with FIRS. Various methods for imaging of the fetal thymus and measurement are described. Currently the only method to diagnose FIRS prenatally is through amniocentesis. We suggest that women who are admitted with preterm labor with intact membranes and those with PPROM should have a detailed sonographic examination of the fetal thymus as a surrogate marker of fetal involvement in intrauterine infection/inflammation processes. © 2015 John Wiley & Sons, Ltd.     

Complementary habitat use by wild bees in agro-natural landscapes

Human activity causes abrupt changes in resource availability across the landscape. In order to persist in human-altered landscapes organisms need to shift their habitat use accordingly. Little is known about the mechanisms by which whole communities persist in human-altered landscapes, including the role of complementary habitat use. We define complementary habitat use as the use of different habitats at different times by the same group of species during the course of their activity period. We hypothesize that complementary habitat use is a mechanism through which native bee species persist in human-altered landscapes. To test this idea, we studied wild bee communities in agro-natural landscapes and explored their community-level patterns of habitat and resource use over space and time. The study was conducted in six agro-natural landscapes in the eastern United States, each containing three main bee habitat types (natural habitat, agricultural fields, and old fields). Each of the three habitats exhibited a unique seasonal pattern in amount, diversity, and composition of floral resources, and together they created phenological complementarity in foraging resources for bees. Individual bee species as well as the bee community responded to these spatiotemporal patterns in floral availability and exhibited a parallel pattern of complementary habitat use. The majority of wild bee species, including all the main crop visitors, used fallow areas within crops early in the season, shifted to crops in mid-season, and used old-field habitats later in the season. The natural-forest habitat supported very limited number of bees, mostly visitors of non-crop plants. Old fields are thus an important feature in these arable landscapes for maintaining crop pollination services. Our study provides a detailed examination of how shifts in habitat and resource use may enable bees to persist in highly dynamic agro-natural landscapes, and points to the need for a broad cross-habitat perspective in managing these landscapes.     

Modified CDKN2B (p15) and CDKN2A (p16) DNA methylation profiles in urban pesticide applicators

Environmental Science and Pollution Research - Gene-specific changes in DNA methylation by pesticides in occupationally exposed populations have not been studied extensively. Of particular concern...