Measuring the discrepancy between fecundity and lifetime reproductive success in a pollinating fig wasp

Lifetime reproductive success in female insects is often egg- or time-limited. For instance in pro-ovigenic species, when oviposition sites are abundant, females may quickly become devoid of eggs. Conversely, in the absence of suitable oviposition sites, females may die before laying all of their eggs. In pollinating fig wasps (Hymenoptera: Agaonidae), each species has an obligate mutualism with its host fig tree species [Ficus spp. (Moraceae)]. These pro-ovigenic wasps oviposit in individual ovaries within the inflorescences of monoecious Ficus (syconia, or ‘figs’), which contain many flowers. Each female flower can thus become a seed or be converted into a wasp gall. The mystery is that the wasps never oviposit in all fig ovaries, even when a fig contains enough wasp females with enough eggs to do so. The failure of all wasps to translate all of their eggs into offspring clearly contributes to mutualism persistence, but the underlying causal mechanisms are unclear. We found in an undescribed Brazilian Pegoscapus wasp population that the lifetime reproductive success of lone foundresses was relatively unaffected by constraints on oviposition. The number of offspring produced by lone foundresses experimentally introduced into receptive figs was generally lower than the numbers of eggs carried, despite the fact that the wasps were able to lay all or most of their eggs. Because we excluded any effects of intraspecific competitors and parasitic non-pollinating wasps, our data suggest that some pollinators produce few offspring because some of their eggs or larvae are unviable or are victims of plant defences.

The ecology of lizard reproductive output

Aim  We provide a new quantitative analysis of lizard reproductive ecology. Comparative studies of lizard reproduction to date have usually considered life-history components separately. Instead, we examine the rate of production (productivity hereafter) calculated as the total mass of offspring produced in a year. We test whether productivity is influenced by proxies of adult mortality rates such as insularity and fossorial habits, by measures of temperature such as environmental and body temperatures, mode of reproduction and activity times, and by environmental productivity and diet. We further examine whether low productivity is linked to high extinction risk. Location  World-wide. Methods  We assembled a database containing 551 lizard species, their phylogenetic relationships and multiple life history and ecological variables from the literature. We use phylogenetically informed statistical models to estimate the factors related to lizard productivity. Results  Some, but not all, predictions of metabolic and life-history theories are supported. When analysed separately, clutch size, relative clutch mass and brood frequency are poorly correlated with body mass, but their product – productivity – is well correlated with mass. The allometry of productivity scales similarly to metabolic rate, suggesting that a constant fraction of assimilated energy is allocated to production irrespective of body size. Island species were less productive than continental species. Mass-specific productivity was positively correlated with environmental temperature, but not with body temperature. Viviparous lizards were less productive than egg-laying species. Diet and primary productivity were not associated with productivity in any model. Other effects, including lower productivity of fossorial, nocturnal and active foraging species were confounded with phylogeny. Productivity was not lower in species at risk of extinction. Main conclusions  Our analyses show the value of focusing on the rate of annual biomass production (productivity), and generally supported associations between productivity and environmental temperature, factors that affect mortality and the number of broods a lizard can produce in a year, but not with measures of body temperature, environmental productivity or diet.

Women, other "fresh” workers, and the new manufacturing workforce of interwar Britain

Structural, organizational, and technological changes in British industry during the interwar years led to a decline in skilled and physically demanding work, while there was a dramatic expansion in unskilled and semiskilled employment. Previous authors have noted that the new un/semiskilled jobs were generally filled by “fresh” workers recruited from outside the core manufacturing workforce, though there is considerable disagreement regarding the composition of this new workforce. This paper examines labour recruitment patterns and strategies using national data and case studies of eight rapidly expanding industrial centres. The new industrial workforce is shown to have been recruited from a “reserve army” of workers with the common features of relative cheapness, flexibility, and weak unionization. These included women, juveniles, local workers in poorly paid nonindustrial sectors, such as agriculture, and (where these other categories were in short supply) relatively young long-distance internal migrants from declining industrial areas.

Reproductive technologies: the owned child and commodification

This article analyses some complexities in and around the idea that the child, in several recent discussions on reproductive technologies, is constantly brought in relation to the market and commodity, and yet is not simply equated with commodity. When and how is the child a commodity and not a commodity?

‘In the air’ and below the horizon: migrant workers in UK construction and the practice-based nature of learning and communicating OHS

Local, tacit and normally unspoken OHS (occupational health and safety) knowledge and practices can too easily be excluded from or remain below the industry horizon of notice, meaning that they remain unaccounted for in formal OHS policy and practice. In this article we stress the need to more systematically and routinely tap into these otherwise ‘hidden’ communication channels, which are central to how everyday safe working practices are achieved. To demonstrate this approach this paper will draw on our ethnographic research with a gang of migrant curtain wall installers on a large office development project in the north of England. In doing so we reflect on the practice-based nature of learning and sharing OHS knowledge through examples of how workers’ own patterns of successful communication help avoid health and safety problems. These understandings, we argue, can be advanced as a basis for the development of improved OHS measures, and of organizational knowing and learning.

Can perceptual differences account for managerial success?: the case of Japanese aid workers

Purpose – There is a wealth of studies which suggest that managers' positive perceptions/expectations can considerably influence the organisational performance; unfortunately, little empirical evidence has been obtained from development studies. This research aims to focus on the perceptual and behavioural trait differences of successful and unsuccessful aid workers, and their relationship with organisational performance. Design/methodology/approach – Through web-based survey, 244 valid responses were obtained from the Japan International Cooperation Agency (JICA)-aid managers worldwide. Five perception related factors were extracted and used for cluster analysis to group the respondents. Each cluster's perception/behaviour-related factors and organisational performance variables were compared by ANOVA. Findings – It was discovered that Japanese's positive perception/expectation about work and their local colleagues was related to higher organisational performance, and conversely, the negative perception on their part was generally associated with negative behaviour and lower organisational performance. Moreover, in a development context, lower work-related stress and feelings of resignation toward work were strongly associated with the acceptability of cross-cultural work environment. Practical implications – The differences in perceptual tendencies suggest that cautious consideration is advised since these findings may mainly apply to Japanese aid managers. However, as human nature is universal, positive perception and behaviour would bring out positive output in most organisations. Originality/value – This study extended the contextualised “Pygmalion effect” and has clarified the influence of perception/expectation on counter-part behaviour and organisational performance in development aid context, where people-related issues have often been ignored. This first-time research provides imperial data on the significant role of positive perception on the incumbent role holder.

Sublethal neonicotinoid insecticide exposure reduces solitary bee reproductive success

1. Pollinating insects provide crucial and economically important ecosystem services to crops and wild plants, but pollinators, particularly bees, are globally declining as a result of various driving factors, including the prevalent use of pesticides for crop protection. Sublethal pesticide exposure negatively impacts numerous pollinator lifehistory traits, but its influence on reproductive success remains largely unknown. Such information is pivotal, however, to our understanding of the long-term effects on population dynamics. 2 We investigated the influence of field-realistic trace residues of the routinely used neonicotinoid insecticides thiamethoxam and clothianidin in nectar substitutes on the entire life-time fitness performance of the red mason bee Osmia bicornis. 3 We show that chronic, dietary neonicotinoid exposure has severe detrimental effects on solitary bee reproductive output. Neonicotinoids did not affect adult bee mortality; however, monitoring of fully controlled experimental populations revealed that sublethal exposure resulted in almost 50% reduced total offspring production and a significantly male-biased offspring sex ratio. 4 Our data add to the accumulating evidence indicating that sublethal neonicotinoid effects on non-Apis pollinators are expressed most strongly in a rather complex, fitness-related context. Consequently, to fully mitigate long-term impacts on pollinator population dynamics, present pesticide risk assessments need to be expanded to include whole life-cycle fitness estimates, as demonstrated in the present study using O. bicornis as a model.

Workers with elderly dependants: employment law’s response to the latest care-giving conundrum

This paper considers how employment laws are being used in response to what we have termed ‘the eldercare/workplace conundrum’. It is well known that people are now living longer but health is still failing in a significant percentage of older people, meaning that many adults require care for longer, albeit to varying degrees and for varying amounts of time. Many of these individuals will receive care from relatives or close friends who are participating in the labour market: this is increasingly likely as adults are expected / wanting to remain in paid work for longer, often into their 60s and 70s. The requirements of elderly dependants can cause these workers huge difficulties and dilemmas as they attempt, across time, to accommodate the particular needs of the person for whom they wish to provide care, often a loved one, and meet the particular demands of their employment relationship. In this paper we consider why this is an area of social policy that warrants effective legal engagement and consider, drawing on various examples of legal responses in other countries that face similar conundrums, what might improve legal engagement in this area.

Biology and reproductive behavior of Murgantia histrionica (Heteroptera: Pentatomidae)

Life history parameters and reproductive behaviors of the harlequin bug, Murgantia histrionica Hahn (Heteroptera: Pentatomidae), were determined. Total developmental time from egg to adult was ≈48 d. After a sexual maturation period of ≈7 d, both sexes mated repeatedly, with females laying multiple egg masses of 12 eggs at intervals of 3 d. Adult females lived an average of 41 d, whereas adult males lived an average of 25 d. Courtship and copulation activities peaked in the middle of the photophase. In mating experiments in which mixed sex pairs of virgin and previously mated bugs were combined in all possible combinations, the durations of courtship and copulation by virgin males were significantly longer with both virgin and previously mated females than the same behaviors for previously mated males. When given a choice between a virgin or previously mated female, previously mated males preferred to mate with virgin females, whereas virgin males showed no preference for virgin over previously mated females. Analyses of mating behaviors with ethograms and behavioral transition matrices suggested that a primary reason for failure to copulate by virgin males was the incorrect rotation of their pygophores to the copulation position, so that successful alignment of the genitalia could not occur.