Functional equivalence of grasping cerci and nuptial food gifts in promoting ejaculate transfer in katydids.

The function of nuptial gifts has generated longstanding debate. Nuptial gifts consumed during ejaculate transfer may allow males to transfer more ejaculate than is optimal for females. However, gifts may simultaneously represent male investment in offspring. Evolutionary loss of nuptial gifts can help elucidate pressures driving their evolution. In most katydids (Orthoptera: Tettigoniidae), males transfer a spermatophore comprising two parts: the ejaculate-containing ampulla and the spermatophylax-a gelatinous gift that females eat during ejaculate transfer. Many species, however, have reduced or no spermatophylaces and many have prolonged copulation. Across 44 katydid species, we tested whether spermatophylaces and prolonged copulation following spermatophore transfer are alternative adaptations to protect the ejaculate. We also tested whether prolonged copulation was associated with (i) male cercal adaptations, helping prevent female disengagement, and (ii) female resistance behavior. As predicted, prolonged copulation following (but not before) spermatophore transfer was associated with reduced nuptial gifts, differences in the functional morphology of male cerci, and behavioral resistance by females during copulation. Furthermore, longer copulation following spermatophore transfer was associated with larger ejaculates, across species with reduced nuptial gifts. Our results demonstrate that nuptial gifts and the use of grasping cerci to prolong ejaculate transfer are functionally equivalent

Increased copulation duration before ejaculate transfer is associated with larger spermatophores, and male genital titillators, across bushcricket taxa

Copulation duration varies considerably across species, but few comparative studies have examined factors that might underlie such variation. We examined the relationship between copulation duration (prior to spermatophore transfer), the complexity of titillators (sclerotized male genital contact structures), spermatophore mass and male body mass across 54 species of bushcricket. Using phylogenetic comparative analyses, we found that copulation duration was much longer in species with titillators than those without, but it was not longer in species with complex compared with simple titillators. A positive relationship was found between spermatophore size and copulation duration prior to ejaculate transfer, which supports the hypothesis that this represents a period of mate assessment. The slope of this relationship was steeper in species with simple rather than complex titillators. Although the data suggest that the presence of titillators is necessary to maintain long copulation prior to ejaculate transfer, mechanisms underlying this association remain unclear

A retrospective review of anorexia nervosa patients admitted to a specialised eating disorders inpatient unit comparing clinical and demographic characteristics of subtypes

A research report submitted to the Faculty of Medicine, Department of Psychiatry, University of the Witwatersrand in partial fulfilment for the degree of Master of Medicine (Psychiatry) Johannesburg 2015Anorexia nervosa is a debilitating illness with the highest mortality rate of all psychiatric illnesses. Subtyping the illness into anorexia nervosa restricting subtype (AN-R) and anorexia nervosa binge-eating/purging subtype (AN-BP) has been a contentious issue since the inception of this subclassification in the 1994 DSM-IV. It has been proposed that there is little difference between the two subgroups and that categorising this eating disorder is of little utility and validity. The aim of this study was to compare the characteristics of a group of anorexic nervosa patients admitted to a specialised inpatient eating disorders unit in Johannesburg, South Africa, to investigate the differences, if any, between the AN-R and AN-BP groups. The hypothesis was that there are aspects of the subtypes which differ and therefore validate the delineation of anorexia nervosa into the two subgroups. The study sample consisted of 59 patients admitted to a specialised inpatient eating disorders unit with the diagnosis of anorexia nervosa, between January 2001 and December 2002. The study group was separated according to their sub-specific anorexia nervosa diagnosis: the AN-R sample (n=32) and the AN-BP sample (n=27). Various demographic and clinical features were reviewed. This study’s only significant result was the difference between the mean percentage of goal weight on admission between the two subtypes, with the average in the AN-R group being lower than that found in the AN-BP group (p-value=0.039). This study therefore does not provide sufficient evidence for the subclassification of anorexia nervosa. It is noted that a small sample size, inaccurate record-keeping and the possibility of diagnostic crossover may have influenced the outcome of this study.MT201