As the covert and clandestine practices of states multiplied in the twentieth century, so did these practices’ footprint in public life. This footprint is not just visual and material but sonic and aural, sounding the ‘secret state’ into being and suggesting ways of ‘listening in’ on it. Using multisensory methodology, this article examines Careless Talk Costs Lives, a UK Second World War propaganda campaign instructing citizens on how to practice discreet speech and listening in defence against ‘fifth columnist’ spies. This campaign reproduced the British secret state in the everyday: it represented sensitive operations as weaving in and out of citizens’ lives through imprudent chatter about ‘hush-hush’ activities and sounds you shouldn't overhear. The paradox at the campaign's heart – of revealing to people the kind of things they shouldn't say or listen to – made the secret state and its international operations a public phenomenon. Secret sounds therefore became entangled within productions of social difference, from class inequalities to German racialisation. Sound and listening, however, are unwieldy phenomena. This sonic life of the secret state risked undermining political legitimacy, while turning public space and idyllic environments into deceptive soundscapes – for international espionage, it seemed, sounded like ordinary life.

It is well known that female adults of frog-biting midges (Corethrellidae) are attracted by anuran mating calls. However, the role of host-emitted cues other than mating calls in determining the level of attraction remains poorly understood. Here, we performed field playback experiments to test how the host-seeking behaviour of Corethrella Coquillett is influenced by different sound stimuli: mating call of a tree frog, cricket call, and no sound. Then, after long-distance host detection, we evaluated if Corethrella can distinguish landing sites by using at short distance the colour and/or shape of anurans. For that, we placed artificial models of frogs with different colours (light green and dark brown) and an artificial caterpillar model (light green colour) on the top of speakers. We found that only frog mating calls presented with the visual cue of an artificial frog were attacked by Corethrella, suggesting that frog shape, regardless of colour, is an important cue for the identification of its hosts. This is the first study providing evidence that after flying long distances guided by frog calls, Corethrella can identify their hosts using visual cues at short distances.

For over 50 years, astronomers have searched the skies for evidence of electromagnetic signals from extraterrestrial (ET) civilizations that have reached or surpassed our level of technological development. Although often overlooked or given as granted, the parallel use of an equivalent communication technology is a necessary prerequisite for establishing contact in both leakage and deliberate messaging strategies. Civilization advancements, especially accelerating change and exponential growth, lessen the perspective for a simultaneous technological status of civilizations thus putting hard constraints on the likelihood of a dialogue. In this paper, we consider the mathematical probability of technological synchronicity of our own and a number of other hypothetical ET civilizations and explore the most likely scenarios for their concurrency. If Search for Extraterrestrial Intelligence (SETI) projects rely on a fortuitous detection of leaked interstellar signals (so-called ‘eavesdropping’) then with minimum prior assumptions N⩾138–4991 Earth-like civilizations have to exist at this moment in the Galaxy for the technological usage synchronicity probability p⩾0.95 in the next 20 years. We also show that since the emergence of complex life, coherent with the hypothesis of the Galactic habitable zone (GHZ), N⩾1497 ET civilizations had to be created in the Galaxy in order to achieve the same estimated probability in the technological possession synchronicity that corresponds to the deliberate signalling scenario.

The Square Kilometre Array (SKA) will operate in frequency ranges often used by military radar and other communications technology. It has been shown that if extraterrestrial intelligences (ETIs) communicate using similar technology, then the SKA should be able to detect such transmissions up to distances of ~100 pc (~300 light years) from Earth. However, Mankind has greatly improved its communications technology over the last century, dramatically reducing signal leakage and making the Earth ‘radio quiet’. If ETIs follow the same pattern as the human race, will we be able to detect their signal leakage before they become radio quiet? We investigate this question using Monte Carlo realization techniques to simulate the growth and evolution of intelligent life in the Galaxy. We show that if civilizations are ‘human’ in nature (i.e. they are only ‘radio loud’ for ~100 years, and can only detect each other with an SKA-like instrument out to 100 pc, within a maximum communication time of 100 years), then the probability for such civilizations accidentally detecting each other is low (~10−7), much lower than if other, dedicated communication techniques are permissible (e.g. optical SETI or neutrino communication).

The plethora of studies devoted to the topics of male competition and female mate choice belie the fact that their interaction remains poorly understood. Indeed, on the question of whether competition should help or hinder the choice process, opinions scattered throughout the sexual selection literature seem unnecessarily polarised. We argue, in the light of recent theoretical and empirical advances, that the effect of competition on mate choice depends on whether it results in the choosy sex attaining high breeding value for total fitness, considering both direct and indirect fitness benefits. Specifically, trade-offs may occur between different fitness benefits if some are correlated with male competitive ability whilst others are not. Moreover, the costs and benefits of mating with competitive males may vary in time and/or space. These considerations highlight the importance of injecting a life-history perspective into sexual selection studies. Within this context, we turn to the sexual selection literature to try to offer insights into the circumstances when competition might be expected to have positive or negative implications for pre-copulatory female choice. In this regard, we elaborate on three stages where competition might impact upon the choice process: (i) during mate detection, (ii) mate evaluation, and (iii) in dictating actual mating outcomes. We conclude by offering researchers several potentially rewarding avenues for future research.