“Quorum Non-Sensing”: Social Cheating and Deception in Vibrio cholerae

Quorum sensing (QS) is widely used by bacteria to coordinate behavior in response to external stimuli. In Vibrio cholerae, this process is important for environmental survival and pathogenesis, though, intriguingly, a large percentage of natural isolates are QS deficient. Here, we show that QS-deficient mutants can spread as social cheaters by ceasing production of extracellular proteases under conditions requiring their growth. We further show that mutants stimulate biofilm formation and are over-represented in biofilms compared to planktonic communities; on this basis, we suggest that QS-deficient mutants may have the side effect of enhancing environmental tolerance of natural populations due to the inherent resistance properties of biofilms. Interestingly, high frequencies of QS-deficient individuals did not impact production of QS signaling molecules despite mutants being unable to respond to these inducers, indicating that these variants actively cheat by false signaling under conditions requiring QS. Taken together, our results suggest that social cheating may drive QS deficiency emergence within V. cholerae natural populations.     

Stories of Gender and Ethnicity: Discourses of colonialism and resistance in Burma1

This paper charts the discursive shift between colonial and ‘post’ colonial discourses about gender and ethnicity in Burma, and attempts to counter such representations by offering alternative stories to those colonialist rumours which have established their status as ‘truth’. The first part deals with missionary discourses in colonial Burma; the second with ‘post’ colonial discourses on Burmese women; and the final section offers stories told by women involved in the political struggles of contemporary Burma. The aim of the paper is to attempt to de-territorialize Burma as a site of colonialist knowledge.     

Decoding the Discourses: Feminism and Science

Revisioning Women, Health and Healing: Feminist, Cultural and Technoscience Perspectives. Adele E. Clarke and Virginia L. Olesen. eds, New York: Routledge, 1999. 374 pp.
Technologies of Procreation: Kinship in the Age of Assisted Conception. Jeanette Edwards. Sarah Franklin. Eric Hirsch, Frances Price, and Marilyn Strathern. New York: Routledge, 1999. 236 pp.
Testing the Women, Testing the Fetus: The Social Impact of Amniocentesis in America. Rayna Rapp. New York: Routledge, 1999. 361 pp.     

Cheating can stabilize cooperation in mutualisms

Mutualisms present a challenge for evolutionary theory. How is cooperation maintained in the face of selection for selfishness and cheating? Both theory and data suggest that partner choice, where one species preferentially directs aid to the more cooperative members of the other species, is central to cooperation in many mutualisms. However, the theory has only so far considered the evolutionary effects of partner choice on one of the species in a mutualism in isolation. Here, we investigate the co-evolution of cooperation and choice in a choosy host and its symbiont. Our model reveals that even though choice and cooperation may be initially selected, it will often be unstable. This is because choice reduces variation in the symbiont and, therefore, tends to remove the selective incentive for its own maintenance (a scenario paralleled in the lek paradox in female choice and policing in within-species cooperation). However, we also show that when variability is reintroduced into symbionts each generation, in the form of less cooperative individuals, choice is maintained. This suggests that the presence of cheaters and cheater species in many mutualisms is central to the maintenance of partner choice and, paradoxically, cooperation itself.     

Status Signalling by Parus major: An Experiment in Deception

The ‘social control’ and ‘incongruence’ hypotheses, first put forward by ROHWER (1977) to explain how attempted ‘deceit’ status signalling is kept in check among winter-flocking birds, were tested under semi-natural conditions for Parus major. This species signals its social status by the width of its breast stripe. The lowest-ranked male in experimental flocks, each made up of four individuals, was manipulated in one of three ways: 1) the status signal was altered by painting the breast stripe to make it broader; 2) agonistic behaviour was altered by injecting testosterone; 3) both status signal and behaviour were manipulated. A study of the outcome of subsequent agonistic encounters by these birds revealed that the status of the manipulated individuals only rose when both their behaviour and status signal were altered. This indicates that the ‘social control’ hypothesis must be rejected, but not the ‘incongruence’ hypothesis.     

The Evolutionary Strategy of Deception

1 A Brief History of Deception
The conceptual roots of deception began to sprout at the dawn of zoology, when Aristotle （350 CE） discussed his observations of the ＇deceitful＇ reproductive tactics of cuckoos and partridges in his classic work The History of Animals. However, the scientific origins of deception were cemented in Descartes＇ （1641） Meditations on First Philosophy, in which he reasoned： All that I have, up to this moment, accepted as possessed of the highest truth and certainty, I received either from or through the senses.     

Cheating in mutualism: defection of Yucca baccata against its yucca moths

Yucca baccata cheats in its obligate pollination/seed predation mutualism with yucca moths. Although all individuals use the pollination services of yucca moths, many individuals do not reciprocate in sustaining yucca moth larvae. Cheating is associated with the morphology of Y. baccata pistils. In Y. baccata , the apex of the ovary contains only inviable ovules, and there are two distinct flower types, one of which has twice as many potentially viable ovules as the other. Because yucca moths oviposit at the apex of Y. baccata ovaries, larvae in flowers with few viable ovules fail to encounter viable ovules and therefore perish. Inflorescences generally have just one flower type, implying that some individuals cheat whereas others maintain the yucca moth population. Our most surprising observation, however, is that although the proportion of cheaters should be low, over 70% of Y. baccata individuals cheat. We hypothesize that both density- and frequency-dependent processes maintain a balance of cheaters and noncheaters in this system.     

Firefly Femmes Fatales: A Case Study in the Semiotics of Deception

Mimicry and deception are two important issues in studies about animal communication. The reliability of animal signs and the problem of the benefits of deceiving in sign exchanges are interesting topics in the evolution of communication. In this paper, we intend to contribute to an understanding of deception by studying the case of aggressive signal mimicry in fireflies, investigated by James Lloyd. Firefly femmes fatales are specialized in mimicking the mating signals of other species of fireflies with the purpose of attracting responding males to become their prey. These aggressive mimics are a major factor in the survival and reproduction of both prey and predator. It is a case of deception through active falsification of information that leads to efficient predation by femmes fatales fireflies and triggered evolutionary processes in their preys’ communicative behaviors. There are even nested coevolutionary interactions between these fireflies, leading to a remarkable system of deceptive and counterdeceptive signaling behaviors. We develop here a semiotic model of firefly deception and also consider ideas advanced by Lloyd about the evolution of communication, acknowledging that deception can be part of the explanation of why communication evolves towards increasing complexity. Increasingly complex sign exchanges between fireflies evolve in an extremely slow pace. Even if deceptive maneuvers are played out time and time again between particular firefly individuals, the evolution of the next level of complexity—and thus the next utterance in the dialogue between species—is likely to take an immense amount of generations.     

The construction of ethnic categories: Discourses of ethnicity in The Netherlands

This article is concerned with the way ethnic and racial categories are achieved and sustained in daily talk. We argue against the notion of social categories as immanent cognitive structures whose existence and significance can be taken for granted. It is emphasized that categories are constructed in discourse. The construction and representation of ethnic categories are studied by analysing discussions held by some ethnically Dutch inhabitants of an inner‐city quarter in Rotterdam. There were two discussion groups (six and five participants respectively) and each group met one evening a week in a row in the local community centre for four weeks. All eight sessions were taped and transcribed and each session lasted approximately two and a half hours. Our goal is to describe in detail some of the discourses that are being used to achieve and sustain specific categorical representations. First, the nature of the different categorical constructs used is analysed. It is shown that people use different criteria for constructing ‘us‐them’ distinctions and that this multiplicity is rhetorically useful. Second, the ways in which categorical constructions are represented and vary in discourse are identified and outlined. Subsequently, the means by which these representations are achieved and sustained is examined. Attention is focued on comparisons that are being made, on the use of metaphors, and on the process of concretiz‐ation. Third, some of the cultural values drawn upon in legitimizing the representations are explored. It is shown how the taken‐for‐granted notions of freedom, merit, equality and tolerance are used to construct and legitimize ethnic representations. Finally, it is argued that a discourse approach can provide important additional insights into issues concerning ethnic relations and racism. For one thing it can help to develop strategies for reconstructing the predominant distinction between ‘us’ and ‘them’.     

Ambiguous Discourses: Performative Approaches to Gender and Race

About Face: Performing Race in Fashion and Theater. Dorinne Kondo. New York: Routledge, 1997. 278 pp.
Beauty and Power: Transgendering and Cultural Transformation in the Southern Philippines. Mark Johnson. Oxford and New York: Berg, 1997. 264 pp.