Sex allocation and local mate competition in Old World non-pollinating fig wasps

The populations of many species are structured such that mating is not random and occurs between members of local patches. When patches are founded by a single female and all matings occur between siblings, brothers may compete with each other for matings with their sisters. This local mate competition (LMC) selects for a female-biased sex ratio, especially in species where females have control over offspring sex, as in the parasitic Hymenoptera. Two factors are predicted to decrease the degree of female bias: (1) an increase in the number of foundress females in the patch and (2) an increase in the fraction of individuals mating after dispersal from the natal patch. Pollinating fig wasps are well known as classic examples of species where all matings occur in the local patch. We studied non-pollinating fig wasps, which are more diverse than the pollinating fig wasps and also provide natural experimental groups of species with different male morphologies that are linked to different mating structures. In this group of wasps, species with wingless males mate in the local patch (i.e. the fig fruit) while winged male species mate after dispersal. Species with both kinds of male have a mixture of local and non-local mating. Data from 44 species show that sex ratios (defined as the proportion of males) are in accordance with theoretical predictions: wingless male species < wing-dimorphic male species < winged male species. These results are also supported by a formal comparative analysis that controls for phylogeny. The foundress number is difficult to estimate directly for non-pollinating fig wasps but a robust indirect method leads to the prediction that foundress number, and hence sex ratio, should increase with the proportion of patches occupied in a crop. This result is supported strongly across 19 species with wingless males, but not across 8 species with winged males. The mean sex ratios for species with winged males are not significantly different from 0.5, and the absence of the correlation observed across species with wingless males may reflect weak selection to adjust the sex ratio in species whose population mating structure tends not to be subdivided. The same relationship is also predicted to occur within species if individual females adjust their sex ratios facultatively. This final prediction was not supported by data from a wingless male species, a male wing-dimorphic species or a winged male species.

Depth to mate and the 50-move rule

The most popular endgame tables (EGTs) documenting ‘DTM’ Depth to Mate in chess endgames are those of Eugene Nalimov but these do not recognise the FIDE 50-move rule ‘50mr’. This paper marks the creation by the first author of EGTs for sub-6-man (s6m) chess and beyond which give DTM as affected by the ply count pc. The results are put into the context of previous work recognising the 50mr and are compared with the original unmoderated DTM results. The work is also notable for being the first EGT generation work to use the functional programming language HASKELL.

Observations on the flight paths of the day-flying moth Virbia lamae during periods of mate location: do males have a strategy for contacting the pheromone plume?

1. To maximize the probability of rapid contact with a female’s pheromone plume, the trajectories of male foraging flights might be expected to be directed with respect to wind flow and also to be energetically efficient. 2. Flights directed either upwind, downwind, or crosswind have been proposed as optimal strategies for rapid and/or energetically efficient plume contact. Other possible strategies are random and Lévy walks, which have trajectories and turn frequencies that are not dictated by the direction of wind flow. 3. The planar flight paths of males of the day-active moth Virbia lamae were recorded during the customary time of its sexual activity. 4. We found no directional preference in these foraging flights with respect to the direction of contemporaneous wind flow, but, because crosswind encompasses twice the possible orientations of either upwind or downwind, a random orientation is in effect a de facto crosswind strategy. 5. A crosswind preference should be favoured when the plume extends farther downwind than crosswind, and this strategy is realized by V. lamae males by a random orientation of their trajectories with respect to current wind direction

Chess endgames: 6-man data and strategy

While Nalimov’s endgame tables for Western Chess are the most used today, their Depth-to-Mate metric is not the most efficient or effective in use. The authors have developed and used new programs to create tables to alternative metrics and recommend better strategies for endgame play.

Chess endgames: data and strategy

While Nalimov’s endgame tables for Western Chess are the most used today, their Depth-to-Mate metric is not the only one and not the most effective in use. The authors have developed and used new programs to create tables to alternative metrics and recommend better strategies for endgame play.

Space-efficient Indexing of Chess Endgame Tables

Chess endgame tables should provide efficiently the value and depth of any required position during play. The indexing of an endgame’s positions is crucial to meeting this objective. This paper updates Heinz’ previous review of approaches to indexing and describes the latest approach by the first and third authors. Heinz’ and Nalimov’s endgame tables (EGTs) encompass the en passant rule and have the most compact index schemes to date. Nalimov’s EGTs, to the Distance-to-Mate (DTM) metric, require only 30.6 × 10^9 elements in total for all the 3-to-5-man endgames and are individually more compact than previous tables. His new index scheme has proved itself while generating the tables and in the 1999 World Computer Chess Championship where many of the top programs used the new suite of EGTs.

Space-efficient indexing of endgame tables for chess

Chess endgame tables should provide efficiently the value and depth of any required position during play. The indexing of an endgame’s positions is crucial to meeting this objective. This paper updates Heinz’ previous review of approaches to indexing and describes the latest approach by the first and third authors. Heinz’ and Nalimov’s endgame tables (EGTs) encompass the en passant rule and have the most compact index schemes to date. Nalimov’s EGTs, to the Distance-to-Mate (DTM) metric, require only 30.6 × 109 elements in total for all the 3-to-5-man endgames and are individually more compact than previous tables. His new index scheme has proved itself while generating the tables and in the 1999 World Computer Chess Championship where many of the top programs used the new suite of EGTs.

3-5-man chess: Maximals and mzugs

This article reports the combined results of several initiatives in creating and surveying complete suites of endgame tables (EGTs) to the Depth to Mate (DTM) and Depth to Conversion (DTC) metrics. Data on percentage results, maximals and mutual zugzwangs, mzugs, has been filed and made available on the web, as have the DTM EGTs.

3-5-Man chess data

This reports the work of Karrer and Wirth in identifying percentage results and, respectively, the Depth to Mate (DTM) and Depth to Conversion (DTC) data in all 2-5-man chess endgames.

Longevity, early emergence and body size in a pollinating fig wasp - implications for stability in a fig-pollinator mutualism

1. Fig trees (Ficus) are pollinated only by agaonid wasps, whose larvae also gall fig ovules. Each ovule develops into either a seed (when pollinated) or a wasp (when an egg is also laid inside) but not both. 2. Ovipositing wasps (foundresses) favour ovules near the centre of the enclosed inflorescence (syconium or 'fig'), leaving ovules near the outer wall to develop into seeds. This spatial stratification of wasps and seeds ensures reproduction in both partners, and thereby enables mutualism persistence. However, the mechanism(s) responsible remain(s) unknown. 3. Theory shows that foundresses will search for increasingly rare inner ovules and ignore outer ovules, as long as ovipositing in outer ovules is sufficiently slow and/or if inner ovules confer greater fitness to wasps. The fig-pollinator mutualism can therefore be stabilized by strong time constraints on foundresses and by offspring fitness gradients over variation in ovule position. 4. Female fig wasps cannot leave their galls without male assistance. We found that females in outer ovules were unlikely to be released. Inner ovules thus have added value to foundresses, because their female offspring are more likely to mate and disperse. 5. For those offspring that did emerge, gall position (inner/outer) and body size did not influence the order in which female pollinators exited syconia, nor did early emerging wasps enjoy increased life spans. 6. We also found that the life spans of female wasps nearly doubled when given access to moisture. We suggest that conflict resolution in the fig-pollinator mutualism may thus be influenced by tropical seasonality, because wasps may be less able to over-exploit ovules in dry periods due to time constraints.

Song development in birds: the role of early experience and its potential effect on rehabilitation success

Environmental conditions during the early life stages of birds can have significant effects on the quality of sexual signals in adulthood, especially song, and these ultimately have consequences for breeding success and fitness. This has wide-ranging implications for the rehabilitation protocols undertaken in wildlife hospitals which aim to return captive-reared animals to their natural habitat. Here we review the current literature on bird song development and learning in order to determine the potential impact that the rearing of juvenile songbirds in captivity can have on rehabilitation success. We quantify the effects of reduced learning on song structure and relate this to the possible effects on an individual's ability to defend a territory or attract a mate. We show the importance of providing a conspecific auditory model for birds to learn from in the early stages post-fledging, either via live- or tape-tutoring and provide suggestions for tutoring regimes. We also highlight the historical focus on learning in a few model species that has left an information gap in our knowledge for most species reared at wildlife hospitals.

Structural variations in Ni(II) complexes of salen type di-Schiff base ligands

Three di-Schiff-base ligands, N,N'-bis(salicylidene)-1,3-propanediamine (H(2)Salpn), N,N'-bis(salicylidene)-1,3-pentanedianiine (H(2)Salpen) and N,N'-bis(salicylidine)-ethylenediamine (H(2)Salen) react with Ni(SCN)(2). 4H(2)O in 2:3 molar ratios to form the complexes; mononuclear [Ni(HSalpn)(NCS)(H2O)]center dot H2O (1a), trinuclear [{Ni(Salpen)}(2)Ni(NCS)(2)] (2b) and trinuclear [{Ni(Salen)}(2)Ni(NCS)(2)] (3) respectively. All the complexes have been characterized by elemental analyses, IR and UV-VIS spectra, and room temperature magnetic susceptibility measurements. The structures of la and 2b have been confirmed by X-ray single crystal analysis. In complex la, the Ni(II) atom is coordinated equatorially by the tetradentate, mononegative Schiff-base, HSalpn. Axial coordination of isothiocyanate group and a water molecule completes its octahedral geometry. The hydrogen atom attached to one of the oxygen atoms of the Schiff base is involved in a very strong hydrogen bond with a neighboring unit to form a centrosymmetric dimer. In 2b, two square planar [Ni(Salpen)] units act as bide mate oxygen donor ligands to a central Ni(II) which is also coordinated by two mutually cis N-bonded thiocyanate ligands to complete its distorted octahedral geometry. Complex 3 possesses a similar structure to that of 2b. A dehydrated form of la and a hydrated form of 2b have been obtained and characterized. The importance of electronic and steric factors in the variation of the structures is discussed. (c) 2007 Elsevier Ltd. All rights reserved.

Forum theorizing in the context of professional practice: The case for middle-range theories

This commentary seeks to complement the contribution of the Building Research & Information special issue on 'Developing Theories for the Built Environment' (2008) by highlighting the important role of middle-range theories within the context of professional practice. Middle-range theories provide a form of theorizing that lies between abstract grand theorizing and atheoretical local descriptions. They are also characterized by the way in which they directly engage with the concerns of practitioners. In the context of professional practice, any commitment to theorizing should habitually be combined with an equivalent commitment to empirical research; rarely is it appropriate to neglect one in favour of the other. Any understanding of the role that theory plays in professional practice must further be informed by Schon's seminal ideas on reflective practice. Practitioners are seen to utilize theories as inputs to a process of continuous reflection, thereby guarding against complacency and routinization. The authors would challenge any assumption that academics alone are responsible for generating theories, thereby limiting the role of practitioners to their application. Such a dichotomized view is contrary to established ideas on Mode 2 knowledge production and current trends towards co-production research in the context of the built environment.

Western Chess: Endgame data

This spreadsheet contains key data about that part of the endgame of Western Chess for which Endgame Tables (EGTs) have been generated by computer. It is derived from the EGT work since 1969 of Thomas Ströhlein, Ken Thompson, Christopher Wirth, Eugene Nalimov, Marc Bourzutschky, John Tamplin and Yakov Konoval. The data includes %s of wins, draws and losses (wtm and btm), the maximum and average depths of win under various metrics (DTC = Depth to Conversion, DTM = Depth to Mate, DTZ = Depth to Conversion or Pawn-push), and examples of positions of maximum depth. It is essentially about sub-7-man Chess but is updated as news comes in of 7-man EGT computations.