Harassment bribes, paid by citizens to corrupt officers for services the former are legally entitled to, constitute one of the most widespread forms of corruption in many countries. Nation states have adopted different policies to address this form of corruption. While some countries make both the bribe giver and the bribe taker equally liable for the crime, others impose a larger penalty on corrupt officers. We examine the consequences of asymmetric and symmetric penalties by developing deterministic and stochastic evolutionary game-theoretic models of bribery. We find that the asymmetric penalty scheme can lead to a reduction in incidents of bribery. However, the extent of reduction depends on how the players update their strategies over time. If the interacting members change their strategies with a probability proportional to the payoff of the alternative strategy option, the reduction in incidents of bribery is less pronounced. Our results indicate that changing from a symmetric to an asymmetric penalty scheme may not suffice in achieving significant reductions in incidents of harassment bribery.

Bribe demands present a social conflict scenario where decisions have wide-ranging economic and ethical consequences. Nevertheless, such incidents occur daily in many countries across the globe. Harassment bribery constitute a significant sub-set of such bribery incidents where a government official demands a bribe for providing a service to a citizen legally entitled to it. We employ an evolutionary game-theoretic framework to analyse the evolution of corrupt and honest strategies in structured populations characterized by an interdependent complex network. The effects of changing network topology, average number of links and asymmetry in size of the citizen and officer population on the proliferation of incidents of bribery are explored. A complex network topology is found to be beneficial for the dominance of corrupt strategies over a larger region of phase space when compared with the outcome for a regular network, for equal citizen and officer population sizes. However, the extent of the advantage depends critically on the network degree and topology. A different trend is observed when there is a difference between the citizen and officer population sizes. Under those circumstances, increasing randomness of the underlying citizen network can be beneficial to the fixation of honest officers up to a certain value of the network degree. Our analysis reveals how the interplay between network topology, connectivity and strategy update rules can affect population level outcomes in such asymmetric games.

We examine a scenario of social conflict that is manifest during an interaction between government servants providing a service and citizens who are legally entitled to the service, using evolutionary game-theory in structured populations characterized by an inter-dependent network. Bribe-demands by government servants during such transactions, called harassment bribes, constitute a widespread form of corruption in many countries. We investigate the effect of varying bribe demand made by corrupt officials and the cost of complaining incurred by harassed citizens, on the proliferation of corrupt strategies in the population. We also examine how the connectivity of the various constituent networks affects the spread of corrupt officials in the population. We find that incidents of bribery can be considerably reduced in a network-structured populations compared to mixed populations. Interestingly, we also find that an optimal range for the connectivity of nodes in the citizen’s network (signifying the degree of influence a citizen has in affecting the strategy of other citizens in the network) as well as the interaction network aids in the fixation of honest officers. Our results reveal the important role of network structure and connectivity in asymmetric games.

3Synthetic gene drive technologies aim to spread transgenic constructs into wild 4 populations even when they impose organismal fitness disadvantages. The prop-5 erties of gene drive constructs are diverse and depend on their molecular con-6 struction, and differential selection pressure they impose in the varied ecological 7 situations they encounter. The extraordinary diversity of conceivable drive mech-8 anisms and the range of selective parameters they may encounter makes it very 9 difficult to convey their relative predicted properties. The sheer number of pub-10 lished manuscripts in this field, experimental and theoretical, is a testament to the 11 possibilities presented by this technology. We evaluate and condense the essen-12 tial synthetic drive mechanisms from a variety of studies and present a unified 13 mathematical paradigm (and a user-friendly tool DrMxR Drive Mixer) describing 14 the properties of a wide variety of single construct gene drives (non-suppression). 15 Within this common framework, we have been able to recapitulate key published 16 results derived using bespoke modelling frameworks. Because a unified frame-17 work is employed, it is also possible to seamlessly explore the consequences 18 of combining multiple drive approaches within a single construct. We provide a 19 1 method for analytically assessing the measure of invasiveness of a drive con-20 struct. As opposed to typical studies of synthetic drives, we explore the resilience 21 of such drives in a spatially explicit manner advancing the connection between 22 realistic spatial dynamics and typical well-mixed populations. Besides a scientific 23 advance, our results and the tools provided an intuitive and objective way for regu-24 lators, scientists and NGOs to evaluate the properties and robustness of proposed 25 and future gene drive approaches. 30Drosophila melanogaster imposes an enormous organismal fitness cost, in that it is 31 homozygous lethal (and only viable as heterozygotes) [Sandler et al., 1959, Sandler 32 and Golic, 1985, Crow, 1991. Consequently, in most circumstances, natural selec-33 tion, at the organismal level would act to eliminate the SD allele. However, because 34 of its capacity to bias the production of SD functional sperm in +/SD heterozygotes, 35 the allele has rapidly increased to an equilibrium frequency of 1-5% in most natural 36 populations around the globe [Hartl, 1975, Hiraizumi and Thomas, 1984, Brand et al., 37 2015]. This natural drive element illustrates how drive elements can increase in fre-38 quency even where there is a substantial cost to (overall) organismal fitness. Since 39 the development of molecular biological techniques, there has been an interest in de-40 veloping synthetic drive elements used to push linked genes into wild populations in a 41 self-perpetuating manner. This is generally termed replacement drive, to distinguish 42 from suppression drive that aims to reduce or completely eradicate the size of target 43 populations upon release. 44 As in ...

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