Honeybee guards do not use food-derived odors to recognize non-nest mates: a test of the Odor Convergence hypothesis

Honeybee (Apis mellifera) colonies rob honey from each other during periods of nectar shortage. Persistent robbing can killweak colonies. Primarily responsible for preventing robbingare guard bees. Previous research has shown that the probabilityof both nest mate and non-nest mate workers being acceptedby guards at the nest entrance increases as nectar availability increases. The mechanism responsible for this change in guardacceptance can be explained by two competing hypotheses: OdorConvergence and Adaptive Threshold Shift. In this study wetested the Odor Convergence hypothesis. The acceptance by guardsat the nest entrance of workers transferred between four coloniesthat had been fed either odorless sucrose syrup (two colonies)or diluted heather honey (Calluna vulgaris) (two colonies)was measured for 3 days before feeding and during 2 weeks offeeding. Despite the large sample sizes, the probability ofguards accepting non-nest mates was not affected by the similaritiesor dissimilarities in food odor between guards' and non-nestmates' colonies. This finding contrasts with the accepted wisdom that food odors are important in nest mate recognition in honeybeesand the data, therefore, strongly reject the Odor Convergencehypothesis.     

Transesterification of farnesol mediated by a lipase from Andrographis tissue cultures

A cell-free system from Andrographis paniculata tissue cultures catalysed the transesterification of administered cis, trans-farnesol-[1-³H₂] with (glyceryl) oleate and palmitate present in the coconut water that forms part of the culture medium.     

The Effect of $1, $5 and $10 Stakes in an Online Dictator Game

The decision rules underpinning human cooperative behaviour are often investigated under laboratory conditions using monetary incentives. A major concern with this approach is that stake size may bias subjects’ decisions. This concern is particularly acute in online studies, where stakes are often far lower than those used in laboratory or field settings. We address this concern by conducting a Dictator Game using Amazon Mechanical Turk. In this two-player game, one player (the dictator) determines the division of an endowment between himself and the other player. We recruited subjects from India and the USA to play an online Dictator Game. Dictators received endowments of $1, $5 or $10. We collected two batches of data over two consecutive years. We found that players from India were less generous when playing with a $10 stake. By contrast, the effect of stake size among players from the USA was very small. This study indicates that the effects of stake size on decision making in economic games may vary across populations.     

Clinical Relevance of Increased Endothelial and Mesothelial Expression of Proangiogenic Proteases and VEGFA in the Omentum of Patients with Metastatic Ovarian High-Grade Serous Carcinoma

Epithelial ovarian cancer (EOC) metastasis to the omentum requires implantation and angiogenesis. We propose that prometastatic changes in the omental endothelium (for angiogenesis) and mesothelium (for implantation) are critical. We investigated the expression of angiogenic proteases [cathepsin D (CD), cathepsin L (CL), and matrix metalloproteinase 2 (MMP2) and MMP9] and vascular endothelial growth factor A (VEGFA) in the mesothelium and endothelium of omentum from patients with EOC with omental metastases and control patients with benign ovarian tumors. Endothelial expression of CL, VEGFA, and MMP9 and mesothelial expression of VEGFA, MMP9, and CD were significantly increased in patients with metastasized EOC. High expression of MMP9 and VEGFA in endothelium and mesothelium and CD in mesothelium was positively associated with poor disease-specific survival (DSS). High MMP9 expression in either endothelium or mesothelium and presence of ascites prospectively showed the greatest risk of shorter DSS [hazard ratio (HR)= 6.16, 95% confidence interval (CI) = 1.76-21.6, P = .0045; HR = 11.42, 95% CI = 2.59-50.35, P = .0013; and HR = 6.35, 95% CI = 2.01-20.1, P = .002, respectively]. High endothelial MMP9 expression and ascites were independent predictors of reduced DSS and overall survival, together resulting in worst patient prognosis. Our data show that omental metastasis of EOC is associated with increased proangiogenic protein expression in the omental endothelium and mesothelium.     

Increased socially mediated plasticity in gene expression accompanies rapid adaptive evolution

Recent theory predicts that increased phenotypic plasticity can facilitate adaptation as traits respond to selection. When genetic adaptation alters the social environment, socially mediated plasticity could cause co‐evolutionary feedback dynamics that increase adaptive potential. We tested this by asking whether neural gene expression in a recently arisen, adaptive morph of the field cricket Teleogryllus oceanicus is more responsive to the social environment than the ancestral morph. Silent males (flatwings) rapidly spread in a Hawaiian population subject to acoustically orienting parasitoids, changing the population's acoustic environment. Experimental altering crickets’ acoustic environments during rearing revealed broad, plastic changes in gene expression. However, flatwing genotypes showed increased socially mediated plasticity, whereas normal‐wing genotypes exhibited negligible expression plasticity. Increased plasticity in flatwing crickets suggests a coevolutionary process coupling socially flexible gene expression with the abrupt spread of flatwing. Our results support predictions that phenotypic plasticity should rapidly evolve to be more pronounced during early phases of adaptation.     

River ecosystem resilience to extreme flood events

Floods have a major influence in structuring river ecosystems. Considering projected increases in high‐magnitude rainfall events with climate change, major flooding events are expected to increase in many regions of the world. However, there is uncertainty about the effect of different flooding regimes and the importance of flood timing in structuring riverine habitats and their associated biotic communities. In addition, our understanding of community response is hindered by a lack of long‐term datasets to evaluate river ecosystem resilience to flooding. Here we show that in a river ecosystem studied for 30 years, a major winter flood reset the invertebrate community to a community similar to one that existed 15 years earlier. The community had not recovered to the preflood state when recurrent summer flooding 9 years later reset the ecosystem back to an even earlier community. Total macroinvertebrate density was reduced in the winter flood by an order of magnitude more than the summer flood. Meiofaunal invertebrates were more resilient to the flooding than macroinvertebrates, possibly due to their smaller body size facilitating greater access to in‐stream refugia. Pacific pink salmon escapement was markedly affected by the winter flood when eggs were developing in redds, compared to summer flooding, which occurred before the majority of eggs were laid. Our findings inform a proposed conceptual model of three possible responses to flooding by the invertebrate community in terms of switching to different states and effects on resilience to future flooding events. In a changing climate, understanding these responses is important for river managers to mitigate the biological impacts of extreme flooding effects.     

The cost of being alone: the fate of floaters in a population of cooperatively breeding pied babblers Turdoides bicolor

The occurrence of group-living behaviour has often been explained by the benefits individuals receive through cooperation; including increased reproductive output, vigilance against predators, and load-lightening behaviour. However, to fully understand the benefits of group-living, it is important to quantify the costs of living alone. Here, we look at the fate of floaters (individuals who have no fixed territory and remain alone for extended periods) in a population of cooperatively breeding pied babblers Turdoides bicolor . We found that individuals spent less time foraging and more time vigilant for predators when found as a floater compared to when they were in a group. Consequently, they suffered a continuous loss of body mass, with long-term floaters suffering the highest losses. This had a long-term effect: floaters that eventually did regain a position in a group usually entered as helpers, in contrast to dispersers, who usually entered a new group as breeders. This high cost of living alone highlights the benefits of group-living and may help to understand patterns of delayed dispersal in some social species.