Evidence of Introgression of the ace-1R Mutation and of the ace-1 Duplication in West African Anopheles gambiae s. s

Background: The role of inter-specific hybridisation is of particular importance in mosquito disease vectors for predicting the evolution of insecticide resistance. Two molecular forms of Anopheles gambiae s.s., currently recognized as S and M taxa, are considered to be incipient sibling species. Hybrid scarcity in the field was suggested that differentiation of M and S taxa is maintained by limited or absent gene flow. However, recent studies have revealed shared polymorphisms within the M and S forms, and a better understanding of the occurrence of gene flow is needed. One such shared polymorphism is the G119S mutation in the ace-1 gene (which is responsible for insecticide resistance); this mutation has been described in both the M and S forms of A. gambiae s.s. Methods and Results: To establish whether the G119S mutation has arisen independently in each form or by genetic introgression, we analysed coding and non-coding sequences of ace-1 alleles in M and S mosquitoes from representative field populations. Our data revealed many polymorphic sites shared by S and M forms, but no diversity was associated with the G119S mutation. These results indicate that the G119S mutation was a unique event and that genetic introgression explains the observed distribution of the G119S mutation within the two forms. However, it was impossible to determine from our data whether the mutation occurred first in the S form or in the M form. Unexpectedly, sequence analysis of some resistant individuals revealed a duplication of the ace-1 gene that was observed in both A. gambiae s.s. M and S forms. Again, the distribution of this duplication in the two forms most likely occurred through introgression. Conclusions: These results highlight the need for more research to understand the forces driving the evolution of insecticide resistance in malaria vectors and to regularly monitor resistance in mosquito populations of Africa

Social media marketing strategy: definition, conceptualization, taxonomy, validation, and future agenda

Although social media use is gaining increasing importance as a component of firms’ portfolio of strategies, scant research has systematically consolidated and extended knowledge on social media marketing strategies (SMMSs). To fill this research gap, we first define SMMS, using social media and marketing strategy dimensions. This is followed by a conceptualization of the developmental process of SMMSs, which comprises four major components, namely drivers, inputs, throughputs, and outputs. Next, we propose a taxonomy that classifies SMMSs into four types according to their strategic maturity level: social commerce strategy, social content strategy, social monitoring strategy, and social CRM strategy. We subsequently validate this taxonomy of SMMSs using information derived from prior empirical studies, as well with data collected from in-depth interviews and a quantitive survey among social media marketing managers. Finally, we suggest fruitful directions for future research based on input received from scholars specializing in the field

Future scenarios of the collaborative economy: Centrally orchestrated, social bubbles or decentralized autonomous?

Purpose: The collaborative economy (CE), and within it, collaborative consumption (CC) has become a central element of the global economy and has substantially disrupted service markets (e.g. accommodation and individual transportation). The purpose of this paper is to explore the trends and develop future scenarios for market structures in the CE. This allows service providers and public policy makers to better prepare for potential future disruption. Design/methodology/approach: Thought experiments – theoretically grounded in population ecology (PE) – are used to extrapolate future scenarios beyond the boundaries of existing observations. Findings: The patterns suggested by PE forecast developmental trajectories of CE leading to one of the following three future scenarios of market structures: the centrally orchestrated CE, the social bubbles CE, and the decentralized autonomous CE. Research limitations/implications: The purpose of this research was to create CE future scenarios in 2050 to stretch one’s consideration of possible futures. What unfolds in the next decade and beyond could be similar, a variation of or entirely different than those described. Social implications: Public policy makers need to consider how regulations – often designed for a time when existing technologies were inconceivable – can remain relevant for the developing CE. This research reveals challenges including distribution of power, insularity, and social compensation mechanisms that need consideration across states and national borders. Originality/value: This research tests the robustness of assumptions used today for significant, plausible market changes in the future. It provides considerabl