The Political Economy of Social Upgrading

Based on a Marxist reworking of the global value chains (GVC) framework, supplemented by insights from structuralist development economics and dependency theory, the thesis investigates what role evolving class relations play in processes of social and economic upgrading in global garment value chains. Situating workers’ agency at the intersection of a horizontal axis (local capital-labor-state relations) and a vertical axis (governance and distributional dynamics of the GVC), the thesis starts out by examining the key features of the 21st century garment GVC and their implications for producer countries. It is shown how a series of interrelated processes, including the transition to neoliberalism in the North, and the phase-out of quotas in the South, combined to produce a “supplier squeeze” in the garment GVC, with a simultaneous depression of export prices and an escalation of non-price requirements. Drawing on the work of the dependentista Marini, it is argued that these distributional dynamics amount to a form of unequal exchange that incentivizes manufacturers to super-exploit workers, pushing their wages below reproduction costs and/or working them beyond exhaustion.

Decoupled Acoustic and Visual Components in the Multimodal Signals of the Common Cuckoo (Cuculus canorus)

Because of its parasitic habits, reproduction costs of the common cuckoo (Cuculus canorus) are mostly spent in pre-laying activities. Female costs are limited to searching host nests and laying eggs, whereas, males spend time in performing intense vocal displays, possibly with territorial purpose. This last aspect, together with a sexual plumage dimorphism, points to both intra- and inter-sexual selections operating within this species. One element triggering sexual selection is a differential fitness accrued by different phenotypes. Before analyzing possible sexual selection mechanisms operating in cuckoos, it is therefore necessary to verify whether there is a variability among male secondary characters by describing and quantifying them. Here we aimed to quantitatively characterize the main two potential candidates of sexual selection traits, i.e., calls and displays, shown by males at perches. During the 2019 breeding season, in a site within the Po Plain, we both audio and video recorded cuckoo males at five different perches. We analyzed acoustic variables as well as display sequences searching for potential correlations. We found a significant variation among calls that could be clustered into four vocal types. We also found that no visual displays were associated with vocal displays; cuckoo males were either vocal and motionless or soundless and active. We discuss our results under the perspective of the potential value of sexual selection in brood parasites and its role in its parasitic habit.

Behavioral and Acoustic Responses of the Oriental Reed Warbler (Acrocephalus orientalis), at Egg and Nestling Stages, to the Common Cuckoo (Cuculus canorus)

Cuckoo nest parasites lay eggs in host nests and thereby transfer all reproduction costs to the hosts. This greatly reduces host fitness. Parasitism has selected for the evolution of anti-parasitic strategies in hosts, including nest defense. The dynamic risk assessment hypothesis holds that nest parasitism only threatens the nests during the egg stage, so hosts should reduce the level of defense against nest parasites after the egg stage. We studied the behavioral and acoustic responses of oriental reed warblers (Acrocephalus orientalis), during both the egg and nestling stages, toward the common cuckoo (Cuculus canorus), sparrowhawks (Accipiter nisus) and oriental turtle doves (Streptopelia orientalis). A. orientalis can visually distinguish cuckoos from sparrowhawks and doves, indicating that hawk mimicry did not work for the cuckoos. The behavioral response of hosts in the nestling stage was stronger than in the egg stage, which supports the offspring value hypothesis and suggests that cuckoos may also act as nest predators. However, there was no difference in the alarm calls A. orientalis produce in response to different invaders, indicating that different types of alarm calls may not contain specific information.

Cost-free lifespan extension via optimization of gene expression in adulthood aligns with the developmental theory of ageing

Ageing evolves because the force of selection on traits declines with age but the proximate causes of ageing are incompletely understood. The ‘disposable soma’ theory of ageing (DST) upholds that competitive resource allocation between reproduction and somatic maintenance underpins the evolution of ageing and lifespan. In contrast, the developmental theory of ageing (DTA) suggests that organismal senescence is caused by suboptimal gene expression in adulthood. While the DST predicts the trade-off between reproduction and lifespan, the DTA predicts that age-specific optimization of gene expression can increase lifespan without reproduction costs. Here we investigated the consequences for lifespan, reproduction, egg size and individual fitness of early-life, adulthood and post-reproductive onset of RNAi knockdown of five ‘longevity’ genes involved in key biological processes in Caenorhabditis elegans . Downregulation of these genes in adulthood and/or during post-reproductive period increases lifespan, while we found limited evidence for a link between impaired reproduction and extended lifespan. Our findings demonstrate that suboptimal gene expression in adulthood often contributes to reduced lifespan directly rather than through competitive resource allocation between reproduction and somatic maintenance. Therefore, age-specific optimization of gene expression in evolutionarily conserved signalling pathways that regulate organismal life histories can increase lifespan without fitness costs.

Specifics of the process of reproduction of land resources in agriculture

The article deals with the features of land resources reproduction in agriculture, reveals the specifics of the stages of the reproduction process: production, distribution, exchange and consumption. The author's position is based on a dual approach to the analysis of the study of the process of reproduction of land resources, which are considered as agricultural land. On the one hand, the reproduction process is studied as the renewal of productive qualities of agricultural land, and on the other hand, as the development and reproduction of land relations in conditions of spatial and institutional limitations that determine the consumer properties of land resources. Unlike other factors of production in the process of reproduction of land resources, the consumption stage is combined with the production stage, which contributes to the beginning of the formation of consumer properties at the production stage and the completion of this process at the consumption stage. According to the monitoring of the functioning of the agricultural land market in the Volgograd region in 2012-2019, according to experts, there are constant jumps in the price of agricultural products with a stable amount of rent, which determines the significance of the influence of the price mechanism on the process of reproduction of land resources. Existing institutional restrictions on the exchange of full and limited ownership rights to agricultural land constrain the process of reproduction of consumer properties of land resources at the stage of exchange and consumption, which leads to an increase in reproduction costs and a decrease in the motivation for effective use of agricultural land.

Male density, a signal for population self-regulation in Alligator sinensis

The regulation of population density is suggested to be indirect and occurs with a time-lag effect, as well as being female centred. Herein, we present a quantitative analysis on the precise, timely and male-dominated self-regulation of Chinese alligator ( Alligator sinensis ) populations. Analysis of 31 years of data revealed gender differences in regulation patterns. Population dynamics were restricted by male density rather than population density, and population growth was halted (birth rate = 0) when male density exceeded 83.14 individuals per hectare, until some males were removed, especially adult males. This rapid and accurate response supports the notions of intrinsic mechanisms and population-wide regulation response. Furthermore, density stress affected mating success rather than parental care to juveniles, i.e. females avoided unnecessary reproduction costs, which may represent an evolutionary advantage. Our findings highlighted the importance of further studies on related physiological mechanisms that focus on four characteristics: quantity breeds quality, gender differences, male density thresholds and nonlinearity.

Reproduction costs can drive the evolution of groups

A fascinating wealth of life cycles is observed in biology, from unicellularity to the concerted fragmentation of multi-cellular units. However, the understanding of factors driving the evolution of life cycles is still limited. We investigate how reproduction costs influence this process. We consider a basic model of a group structured population of undifferentiated cells, where groups reproduce by fragmentation. Fragmentation events are associated with a cost expressed by either a fragmentation delay, a fragmentation risk, or a fragmentation loss. The introduction of such fragmentation costs vastly increases the set of potentially optimal life cycles. Based on these findings, we suggest that the evolution of life cycles and the splitting into multiple offspring can be directly associated with the fragmentation cost. Moreover, the impact of this cost alone is strong enough to drive the emergence of multicellular groups, even under scenarios that strongly disfavour groups compared to solitary individuals.

Simulated mammal browsing and host gender effects on dual mycorrhizal Salix repens

We studied effects of simulated browsing and host plant gender on mycorrhizal status of dioecious Salix repens, forming both ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) symbioses. Owing to their lower biomass production, AM fungi may require less carbon from the host and have a competitive advantage over ECM fungi when carbon availability is reduced. Further, in dioecious plants, females have generally higher reproduction costs than males. Hence, herbivory may be especially detrimental to female plants and their ECM symbionts in favour of AM symbionts. Fifty percent shoot clipping increased the number of vegetative shoots but reduced the proportion of flowering shoots equally in male and female hosts. Despite clipping, ECM and AM colonization remained unchanged. However, slightly reduced soil fungal biomass was found in clipped patches of male S. repens. Our novel finding of AM spores occurring in the ECM fungal mantle of S. repens roots suggests that both mycorrhizal partners may coexist in the same root segment. Since no interaction between gender and clipping in fungal parameters was detected, we conclude that female and male S. repens are equally preferable hosts for fungal symbionts, even when carbohydrate availability has been decreased because of herbivory.