A novel type of nutritional ant-plant interaction: ant partners of carnivorous pitcher plants prevent nutrient export by dipteran pitcher infauna.

Many plants combat herbivore and pathogen attack indirectly by attracting predators of their herbivores. Here we describe a novel type of insect-plant interaction where a carnivorous plant uses such an indirect defence to prevent nutrient loss to kleptoparasites. The ant Camponotus schmitzi is an obligate inhabitant of the carnivorous pitcher plant Nepenthes bicalcarata in Borneo. It has recently been suggested that this ant-plant interaction is a nutritional mutualism, but the detailed mechanisms and the origin of the ant-derived nutrient supply have remained unexplained. We confirm that N. bicalcarata host plant leaves naturally have an elevated (15)N/(14)N stable isotope abundance ratio (δ(15)N) when colonised by C. schmitzi. This indicates that a higher proportion of the plants' nitrogen is insect-derived when C. schmitzi ants are present (ca. 100%, vs. 77% in uncolonised plants) and that more nitrogen is available to them. We demonstrated direct flux of nutrients from the ants to the host plant in a (15)N pulse-chase experiment. As C. schmitzi ants only feed on nectar and pitcher contents of their host, the elevated foliar δ(15)N cannot be explained by classic ant-feeding (myrmecotrophy) but must originate from a higher efficiency of the pitcher traps. We discovered that C. schmitzi ants not only increase the pitchers' capture efficiency by keeping the pitchers' trapping surfaces clean, but they also reduce nutrient loss from the pitchers by predating dipteran pitcher inhabitants (infauna). Consequently, nutrients the pitchers would have otherwise lost via emerging flies become available as ant colony waste. The plants' prey is therefore conserved by the ants. The interaction between C. schmitzi, N. bicalcarata and dipteran pitcher infauna represents a new type of mutualism where animals mitigate the damage by nutrient thieves to a plant

Capability in the digital: institutional media management and its dis/contents

This paper explores how social media spaces are occupied, utilized and negotiated by the British Military in relation to the Ministry of Defence’s concerns and conceptualizations of risk. It draws on data from the DUN Project to investigate the content and form of social media about defence through the lens of ‘capability’, a term that captures and describes the meaning behind multiple representations of the military institution. But ‘capability’ is also a term that we hijack and extend here, not only in relation to the dominant presence of ‘capability’ as a representational trope and the extent to which it is revealing of a particular management of social media spaces, but also in relation to what our research reveals for the wider digital media landscape and ‘capable’ digital methods. What emerges from our analysis is the existence of powerful, successful and critically long-standing media and reputation management strategies occurring within the techno-economic online structures where the exercising of ‘control’ over the individual – as opposed to the technology – is highly effective. These findings raise critical questions regarding the extent to which ‘control’ and management of social media – both within and beyond the defence sector – may be determined as much by cultural, social, institutional and political influence and infrastructure as the technological economies. At a key moment in social media analysis, then, when attention is turning to the affordances, criticisms and possibilities of data, our research is a pertinent reminder that we should not forget the active management of content that is being similarly, if not equally, effective

Video games and agency in contemporary society

In recent years, the idea of player control, or agency, has become central and explicit in certain video games and genres, affecting many debates concerning the study or definitions of video games. In spite of this, the notion of agency in video games has been rarely explicitly explored or defined in relation to its sociological and political dimensions. Hence, drawing on actor-network theory, (neo-)Foucauldian governmentality studies, and empirical data gathered over a three-year period, this paper expands to our understanding of video game player agency and moreover, argues that video games provide an important example and perspective to consider the contemporary nature and political basis of agency

Flux of nitrogen from ant colony to pitcher plant.

<p>Bars indicate the change in ¹⁵N abundance in the leaves of a <i>N. bicalcarata</i> plant two weeks after feeding a ¹⁵N pulse to the symbiotic <i>C. schmitzi</i> colony. Leaf node 1 bears the youngest leaf. The pictogrammes under the graph explain the structure of the host plant, its ant colony and mark where tracer was fed.</p

Samples taken for the analysis of the natural abundance of ¹⁵N in <i>N. bicalcarata</i> phytotelm food webs.

<p>Each of the ten pitchers grew on a different plant, and food web components were sampled and analysed from each pitcher separately. “Other larvae” refers to Brachycera and putative non-predatory Nematocera.</p

Adult infauna emerged from <i>N. bicalcarata</i> pitchers. Unless otherwise stated, values are total numbers of individuals.

<p>Adult infauna emerged from <i>N. bicalcarata</i> pitchers. Unless otherwise stated, values are total numbers of individuals.</p

Schematic of “emergence trap” for pitcher plant infauna.

<p>The lower bottle containing the pitcher is completely darkened, causing emerging dipterans to move upwards towards the light shining through the neck. Tanglefoot® prevents crawling insects from entering the collection bottle. The fish trap-like design prevents escape from the collection bottle. Emerging insects reaching the collection bottle were killed when falling into a 1.5% CuSO₄ solution. Traps were stabilised with a pole. Whole, living pitchers could be used without significant interference. Although <i>C. schmitzi</i> could freely pass through a small gap in the bottle along the pitcher tendril, the trap was mosquito-tight (without ants, all the 20 inserted individuals were always recovered; n = 10 traps).</p

Effect of <i>C.schmitzi</i> presence on numbers of surviving <i>Aedes</i> sp. pupae and successfully emerging mosquitoes.

<p>The experiment started with 20 living pupae in each pitcher. Boxplot shows medians, interquartile ranges, and the largest and smallest values that are not outliers (outliers shown as circles).</p

Natural δ¹⁵N for the components of the investigated food-web.

<p>Included are non-carnivorous plants (“non-CPs”, n = 7), <i>N. bicalcarata</i> plants (highlighted in grey; climbers without ants, n = 15; climbers with ants, n = 17; rosettes without ants, n = 15; rosettes with ants, n = 11), prey insects (n = 6), pitcher detritus (n = 10; one outlier with δ¹⁵N = 11.42 ‰ not shown), ‘other’ dipteran larvae (n = 10), ‘predatory’ dipteran larvae (n = 5) and <i>C. schmitzi</i> ants (n = 5). The dotted horizontal line highlights the level of prey insects. Boxplot shows medians, interquartile ranges, and the largest and smallest values that are not outliers (outliers shown as circles).</p

Amphibia, Anura, Hylidae, Scarthyla vigilans (Solano, 1971): range extension and new country record for Trinidad, West Indies, with notes on tadpoles, habitat, behavior and biogeographical significance

We report a range extension and new country record for Scarthyla vigilans in Trinidad, West Indies. The species was previously known only from populations on mainland South America. We include notes on behavior, habitat and tadpole development, and discuss the biogeographical significance of the species’ presence in Trinidad, particularly with respect to consequences for understanding colonization events on this Caribbean island