Females restrict the position of domatia and suffer more herbivory than hermaphrodites in Myriocarpa longipes, a neotropical facultative myrmecophyte

Domatia are hollow structures in plants occupied by ant colonies, in turn ants provide protection against herbivores. In plants, competition for resources has driven sex-related changes in the patterns of resource allocation to life-history traits and defence traits. The resource-competition hypothesis (RCH) proposes that female plants due to their higher investment in reproduction will allocate fewer resources to defence production, showing greater herbivore damage than other sexual forms. We hypothesise the existence of sex-related differences in defensive traits of domatia-bearing plants, being female plants less defended due to differences in domatia traits, such as size, number of domatia and their position, exhibiting more herbivore damage than hermaphrodite plants of Myriocarpa longipes, a facultative neotropical myrmecophyte. We found eight species of ants inhabiting domatia; some species co-inhabited the same plant, even the same branch. Our results are consistent with the predictions of RCH, as female plants had ant-inhabited domatia restricted to the middle position of their branches and exhibited greater herbivore damage in leaves than hermaphrodites. However, we did not find differences in domatia size and leaf area between sexual forms. Our study provides evidence for intersexual differences in domatia position and herbivory in a facultative ant–plant mutualism in M. longipes. We highlight the importance of considering the plant sex in ant–plant interactions. Differences in resource allocation related to sexual reproduction could influence the outcome of ant–plant interactions.

Evolution of enzyme levels in metabolic pathways: A theoretical approach. Part 2

Metabolism is essential for cell function and adaptation. Because of their central role in metabolism, kinetic parameters and enzyme concentrations are under constant selective pressure to adapt the fluxes of the metabolic networks to the needs of the organism. In the line of various studies dealing with enzyme evolution, we recently developed a model of evolution of enzyme concentrations under selection for increased flux, considered as a proxy of fitness (Coton 2021). Taking into account two realistic cellular constraints, competition for resources and co-regulations, we determined the evolutionary equilibria and the ranges of neutral variations of enzyme concentrations. In this article, we give more generality to this model, by considering that the enzymes of a pathway can belong to different groups of co-regulation. We determined the equilibria and showed that the constraints modify the adaptive landscape by limiting the number of independent dimensions. We also showed that any trade-off between enzyme concentration is sufficient to limit the flux and to relax selection for increasing other enzyme concentrations. Even though the model is based on simplifying assumptions, the complexity of the relationship between enzyme concentrations prevents the analysis of selective neutrality.

Crimes of Consumption: Polemical uses of Gluttony and Cannibalism in English Print, 1580-1625

<p>Attacks on excessive consumption are an enduring theme in Western biblical and Greco- Roman thought. This dissertation attempts to unravel the cultural and political context of two such critiques. The 'culture' of gluttony at the Court of King James still stands as a stereotype largely left unchanged by the recent revisionist historiography. This dissertation argues that James's Court was unexceptional when placed in the context of other English and European Courts. Polemical attacks on the culture of 'gluttony' at the Court of King James were motivated by political contest. Proximity to the King's person allowed for unrivalled privilege and reward. The attacks on James's new favourites came from the old nobility, once at the centre, and now relegated to the periphery, while those targeted, James's 'new men', came from the periphery. Competition for resources also informed the allegations of cannibalism made against New World peoples. Under the Spanish, attacks against the 'cannibals' at the periphery were designed to justify the appropriation of their resources. The English, when their opportunity came, could no longer convincingly accuse those at the periphery of cannibalism. New economic arguments and empirical science together promoted a new focus on 'culture', which suggested that Amerindians belonged at the periphery. At some stage in their 'development' and under proper Christian tutelage, and if they behaved themselves, they might be incorporated into the centre. In the meantime, English 'trade and friendship' would assist in their education. This dissertation makes an original contribution by demonstrating that bodily practices sit at the heart of enduring political contests.</p>

Crimes of Consumption: Polemical uses of Gluttony and Cannibalism in English Print, 1580-1625

<p>Attacks on excessive consumption are an enduring theme in Western biblical and Greco- Roman thought. This dissertation attempts to unravel the cultural and political context of two such critiques. The 'culture' of gluttony at the Court of King James still stands as a stereotype largely left unchanged by the recent revisionist historiography. This dissertation argues that James's Court was unexceptional when placed in the context of other English and European Courts. Polemical attacks on the culture of 'gluttony' at the Court of King James were motivated by political contest. Proximity to the King's person allowed for unrivalled privilege and reward. The attacks on James's new favourites came from the old nobility, once at the centre, and now relegated to the periphery, while those targeted, James's 'new men', came from the periphery. Competition for resources also informed the allegations of cannibalism made against New World peoples. Under the Spanish, attacks against the 'cannibals' at the periphery were designed to justify the appropriation of their resources. The English, when their opportunity came, could no longer convincingly accuse those at the periphery of cannibalism. New economic arguments and empirical science together promoted a new focus on 'culture', which suggested that Amerindians belonged at the periphery. At some stage in their 'development' and under proper Christian tutelage, and if they behaved themselves, they might be incorporated into the centre. In the meantime, English 'trade and friendship' would assist in their education. This dissertation makes an original contribution by demonstrating that bodily practices sit at the heart of enduring political contests.</p>

Catching the thief: Nectar robbing behaviour by bumblebees on naturalised Fuchsia magellanica in Ireland

Fuchsia magellanica (Ongaraceae) is a plant with a traditionally ornithopholous pollination system, pollinated primarily by hummingbirds in its native range. As a naturalised alien plant in Ireland, F. magellanica is visited largely by bumblebees, with evidence for nectar robbing behaviour of the long-tubed flowers. We aimed to investigate nectar robbing behaviour of bumblebees on F. magellanica, and in particular whether floral and pollinator traits (size) determined likelihood of nectar robbing. While F. magellanica was visited by a number of bumblebee species, only two with shorter tongue lengths were observed to rob nectar from flowers. Although there was no observed relationship between intra-specific bee body size and nectar robbing behaviour, nectar robbing was observed most frequently in the site with the highest number of bees. Proportions of robbed flowers were low overall and varied between populations, but there was a significant relationship between flower size and whether it was nectar robbed with larger flowers robbed more often. Our work suggests that floral size determines whether a flower-visitor will choose to nectar rob or not in this system. Nectar robbing may also be related to bee density which could suggest this behaviour is driven by competition for resources, or that it is learnt by observing other bees.

Cross-feeding shapes both competition and cooperation in microbial ecosystems

Recent work suggests that cross-feeding -- the secretion and consumption of metabolic biproducts by microbes -- is essential for understanding microbial ecology. Yet how cross-feeding and competition combine to give rise to ecosystem-level properties remains poorly understood. To address this question, we analytically analyze the Microbial Consumer Resource Model (MiCRM), a prominent ecological model commonly used to study microbial communities. Our mean-field solution exploits the fact that unlike replicas, the cavity method does not require the existence of a Lyapunov function. We use our solution to derive new species-packing bounds for diverse ecosystems in the presence of cross-feeding, as well as simple expressions for species richness and the abundance of secreted resources as a function of cross-feeding (metabolic leakage) and competition. Our results show how a complex interplay between competition for resources and cooperation resulting from metabolic exchange combine to shape the properties of microbial ecosystems.

The correlation of globalization and localization of economic processes in the context of growing global risks

The article analyses changes in the correlation between globalization and localization of economic processes in the context of increasing global instability, growing geopolitical rivalry and the emergence and spread of new global risks of technological, ecological and biological origin. The study proves that the growth of global risks leads to a modification of Maslow's hierarchy of needs towards a relative accentuation of security needs - with diverse consequences in terms of the territorial organization of economic activity and mobility. It substantiates that the expansion of global processes can lead to excessive levels of concentration and homogenization of economic processes, suppression of forms of self-organization at the local level, and creating risks of disrupting the stability of local socio-economic structures. An important consequence is the transformation of the globalization process due to a significant intensification of regional and local factors. This trend determines the formation of glocalization as a two-dimensional process in which globalization and localization trends are combined. The author postulates that the balance between the processes of globalization and localization can shift in favor of the latter due to: the exacerbation of the global competition for resources and markets in the context of cardinal technological and structural shifts in the world economy; increasing international instability amid geopolitical confrontation between old and new centers of global power; insufficient effectiveness of global responses to climate change and pandemics; risks of the digital virtual environment leading to increased national and regional regulation and fragmentation of the global digital environment; and the impact of technologies of the Fourth Industrial Revolution in the direction of strengthening localization trends in relation to global value chains.

Frequency-dependent hybridization contributes to habitat segregation in monkeyflowers

Spatial segregation of closely related species is usually attributed to differences in stress tolerance and competitive ability. For both animals and plants, reproductive interactions between close relatives can impose a fitness cost that is more detrimental to the rarer species. Frequency-dependent mating interactions may thus prevent the establishment of immigrants within heterospecific populations, maintaining spatial segregation of species. Despite strong spatial segregation in natural populations, two sympatric California monkeyflowers (Mimulus nudatus and M. guttatus) survive and reproduce in the other's habitat when transplanted reciprocally. We hypothesized that a frequency-dependent mating disadvantage maintains spatial segregation of these monkeyflowers during natural immigration. To evaluate this hypothesis, we performed two field experiments. First, we experimentally added immigrants in varying numbers to sites dominated by heterospecifics. Second, we reciprocally transplanted arrays of varying resident and immigrant frequency. Immigrant seed viability decreased with conspecific rarity for M. guttatus, but not M. nudatus. We observed immigrant minority disadvantage for both species, but driven by different factors- frequency-dependent hybridization for M. guttatus, and competition for resources and/or pollinators for M. nudatus. Overall, our results suggest a potential major role for reproductive interference in spatial segregation that should be evaluated along with stress tolerance and competitive ability.

Fruit Set in Avocado: Pollen Limitation, Pollen Load Size, and Selective Fruit Abortion

Avocado is a woody perennial fruit crop originating in Central America and Mexico domesticated and cultivated in the Americas since pre-Columbian times, currently cultivated in subtropical, tropical, and Mediterranean climates worldwide, with increasing importance in international trade. Avocado shows an exuberant flower production that, however, results in a very low fruit set reflected in a massive abscission of flowers and fruitlets. Several factors are involved in this behavior, and, in this work, we have focused on pollination limitation. The results obtained show that pollen deposition takes place at the female and male stages during the avocado flowering season and that the percentage of flowers with pollen on the stigma varies along the flowering season, probably due to changes in temperature that affect not only the floral behavior but also pollinator activity. However, no embryo or endosperm development took place when pollination occurred during the male flowering phase. Thus, the low number of pollen grains landing on the stigmas of female stage flowers observed under natural pollination conditions might not be enough to ensure a good yield. The production of an excess of flowers and subsequent flower drop of most of the flowers provides the opportunity of a selective fruitlet drop depending on the genotype of the embryo since fruits derived from outcrossing showed higher chances of reaching maturity. Moreover, an important competition for resources occurs among developing fruits and new vegetative growth, conferring importance to the time of flower fertilization for effective fruit set.

A Shape to Die for?

The product of natural selection over at least 15 million years is the elongated, slender shape of giraffes that fits the natural habitat giraffes now occupy. What selection pressures operated to produce their shape? Their shape is partly the product of gravity and could have been an accidental by-product of selection for a large body mass and the protection from predation that large size brings, but the prevailing explanation is that their shape confers a browsing advantage. Preferred browse is concentrated at a height easily reached by giraffes but not by other browsers and natural selection would have favored those giraffes that could reach it. An alternative hypothesis is that their shape confers thermoregulatory benefits in addition to improved vigilance. Another hypothesis is that a long neck evolved to counter long legs allowing giraffes to drink surface water. An attractive hypothesis is that their shape is a product of ‘runaway’ sexual selection by females for males with long heavy necks, but analysis of this hypothesis has shown that the morphology of male and female giraffe does not differ. Nevertheless, all these possibilities could have contributed. A consequence of selection for their shape is over-specialization: giraffes seem to be inextricably dependent on a narrow diet, a diet that is subject to the vagaries of climate and competition for resources. The greatest threat to their survival is, therefore, their shape.