Mating behavior and chemical communication in the order hymenoptera

Insects of the order Hymenoptera are biologically and economically important members of natural and agro ecosystems and exhibit diverse biologies, mating systems, and sex pheromones. We review what is known of their sex pheromone chemistry and function, paying particular emphasis to the Hymenoptera Aculeata (primarily ants, bees, and sphecid and vespid wasps), and provide a framework for the functional classification of their sex pheromones. Sex pheromones often comprise multicomponent blends derived from numerous exocrine tissues, including the cuticle. However, very few sex pheromones have been definitively characterized using bioassays, in part because of the behavioral sophistication of many Aculeata. The relative importance of species isolation versus sexual selection in shaping sex pheromone evolution is still unclear. Many species appear to discriminate among mates at the level of individual or kin/colony, and they use antiaphrodisiacs. Some orchids use hymenopteran sex pheromones to dupe males into performing pseudocopulation, with extreme species specificity.

Translating ‘gaytown’: the collision of global and local in bringing Australian queer play Bison to Belfast.

Sydney playwright Lachlan Philpott’s Bison (2000/2009) is immersed in a sweaty, summery Antipodean scene of bronzed and toned bodies. It is located in the flora and fauna of gum trees and biting ants. Yet, despite this, it could be argued that at its heart it is not a specifically Australian site, but an all-too translatable scene that seems to be played out in gay clubs, bars, chatrooms and saunas around the Western world: men repeating patterns, looking for sex or love; checking out bodies, craving perfection; avoiding, and occasionally seeking, disease. At least, that was my assumption when I decided to direct the play in Belfast, Northern Ireland, in 2009. Philpott came to Belfast to workshop the play with the actors and, as a group, we restructured the play and tried to find a way to ‘de-Australianise’ it without necessarily placing it in a new geographical place - Northern Ireland - through linguistic clues in the text. As Philpott put it: ‘Let’s not make this play about Belfast or Sydney or London or anywhere because it is not a fair reflection of these scenes. Maybe we should just identify the generic elements of this world and then make Bison a play that reflects gaytown – because the rituals are all the same in Western society’. The experience of doing the play in Belfast made clear, however, that ideas of a global gay identity/experience –though highly marketed – fail to account for the vastly different situations of embodied gay experience. And the Northern Irish gay experience, while it has imported the usual ‘generic’ tropes of gayness, sits within a specific cultural context in which the farsighted legislation on equality for gays (imposed by either London or the EU) vastly outstrips wider societal thinking. For many in Northern Ireland, erstwhile MP Iris Robinson’s comments about homosexuality being an ‘abomination’ were a reason to support her, rather than to reject her. For me, the comments were the catalyst to doing Bison in Belfast.

Cryptic plasticity underlies a major evolutionary transition

The origin of eusociality is often regarded as a change of macroevolutionary proportions [1, 2]. Its hallmark is a reproductive division of labor between the members of a society: some individuals ("helpers" or "workers") forfeit their own reproduction to rear offspring of others ("queens"). In the Hymenoptera (ants, bees, wasps), there have been many transitions in both directions between solitary nesting and sociality [2-5]. How have such transitions occurred? One possibility is that multiple transitions represent repeated evolutionary gains and losses of the traits underpinning sociality. A second possibility, however, is that once sociality has evolved, subsequent transitions represent selection at just one or a small number of loci controlling developmental switches between preexisting alternative phenotypes [2, 6]. We might then expect transitional populations that can express either sociality or solitary nesting, depending on environmental conditions. Here, we use field transplants to directly induce transitions in British and Irish populations of the sweat bee Halictus rubicundus. Individual variation in social phenotype was linked to time available for offspring production, and to the genetic benefits of sociality, suggesting that helping was not simply misplaced parental care [7]. We thereby demonstrate that sociality itself can be truly plastic in a hymenopteran.

Ant-lore in Anglo-Saxon England

Two Old English versions of a sunshine prognostication survive in the mid-eleventh century Cambridge, Corpus Christi College 391, p. 713, and in a twelfth-century addition to Oxford, Bodleian Library, Hatton 115, 149v–150r. Among standard predictions promising joy, peace, blossom, abundance of milk and fruit, and a great baptism sent by God, one encounters an enigmatic prophecy which involves camels stealing gold from the ants. These gold-digging ants have a long pedigree, one which links Old English with much earlier literature and indicates the extent to which Anglo-Saxon culture had assimilated traditions of European learning. It remains difficult to say what is being prophesied, however, or to explain the presence of the passage among conventional predictions. Whether the prediction was merely a literary exercise or carried a symbolic implication, it must have originated in an ecclesiastical context. Its mixture of classical learning and vernacular tradition, Greek and Latin, folklore and Christian, implies an author with some knowledge of literary and scholarly traditions.

Mean field approach for tracking similar objects

In this paper, we consider the problem of tracking similar objects. We show how a mean field approach can be used to deal with interacting targets and we compare it with Markov Chain Monte Carlo (MCMC). Two mean field implementations are presented. The first one is more general and uses particle filtering. We discuss some simplifications of the base algorithm that reduce the computation time. The second one is based on suitable Gaussian approximations of probability densities that lead to a set of self-consistent equations for the means and covariances. These equations give the Kalman solution if there is no interaction. Experiments have been performed on two kinds of sequences. The first kind is composed of a single long sequence of twenty roaming ants and was previously analysed using MCMC. In this case, our mean field algorithms obtain substantially better results. The second kind corresponds to selected sequences of a football match in which the interaction avoids tracker coalescence in situations where independent trackers fail.