Sexual selection on population-level mating opportunities drives morph ratios in a fig wasp with extreme male dimorphism

Background: Alternative mating tactics are widespread in animals and associated with extreme morphological polymorphism in some insects. Some fig wasps have both highly modified wingless males and dispersing winged males. Wingless males mate inside figs before females disperse, while winged males mate elsewhere after dispersal. Hamilton proposed a model for this system with morphs determined by alternative alleles. This has an equilibrium where the proportion of winged males equals the proportion of females dispersing unmated; i.e. the proportion of matings that they obtain. Previously, we have shown qualitative support for this prediction across nine wing-dimorphic fig wasp species. Here I test the quantitative prediction in the fig wasp Pseudidarnes minerva. In addition, some fig wasp species that lack winged males, but have two wingless morphs, show a conditional strategy with morph determination influenced by the number of wasps developing in a patch. I also test for this alternative pattern in the wing-dimorphic P. minerva. Results: I sampled 114 figs that contained a mean of 2.1 P. minerva wasps from 44 trees across four sites in Sydney, Australia. At the whole population level, the proportion of winged males (0.84 or 0.79 corrected for sampling bias) did not differ significantly from the proportion of unmated females (0.84), providing strong quantitative support for the prediction of Hamilton’s model. In addition, there was no evidence for other factors, such as local mate competition or fighting between wingless males, that could violate simplifying assumptions of the model. Meanwhile, the proportion of winged males was not correlated with the number of wasps per fig, providing no evidence for a conditional strategy. Conclusion: The morph ratio in P. minerva is consistent with Hamilton’s simple Mendelian strategy model, where morph ratios are set by average mating opportunities at the population level. This contrasts with some fig wasps from another subfamily that show conditional morph determination, allowing finer scale adaptation to fig-level mating opportunities. However, these conditional cases do not involve wing polymorphism. Male polymorphism is common and variable in fig wasps and has evolved independently in multiple lineages with apparently different underlying mechanisms

Magnetic Braking and Viscous Damping of Differential Rotation in Cylindrical Stars

Differential rotation in stars generates toroidal magnetic fields whenever an initial seed poloidal field is present. The resulting magnetic stresses, along with viscosity, drive the star toward uniform rotation. This magnetic braking has important dynamical consequences in many astrophysical contexts. For example, merging binary neutron stars can form "hypermassive" remnants supported against collapse by differential rotation. The removal of this support by magnetic braking induces radial fluid motion, which can lead to delayed collapse of the remnant to a black hole. We explore the effects of magnetic braking and viscosity on the structure of a differentially rotating, compressible star, generalizing our earlier calculations for incompressible configurations. The star is idealized as a differentially rotating, infinite cylinder supported initially by a polytropic equation of state. The gas is assumed to be infinitely conducting and our calculations are performed in Newtonian gravitation. Though highly idealized, our model allows for the incorporation of magnetic fields, viscosity, compressibility, and shocks with minimal computational resources in a 1+1 dimensional Lagrangian MHD code. Our evolution calculations show that magnetic braking can lead to significant structural changes in a star, including quasistatic contraction of the core and ejection of matter in the outermost regions to form a wind or an ambient disk. These calculations serve as a prelude and a guide to more realistic MHD simulations in full 3+1 general relativity.Comment: 20 pages, 19 figures, 3 tables, AASTeX, accepted by Ap

Book Reviews

Reviews of the following books: Lobstering and The Maine Coast by Kenneth R. Martin and Nathan R. Lipfert; Beothuk Bark Canoes: An Analysis and Comparative Study by Ingeborg C.L. Marshall; Records of Meduncook Plantation and Friendship Maine, 1763-1899 edited by Melville B. Cook

Non-symmetric liquid crystal dimer containing a carbohydrate-based moiety

Peer reviewedPublisher PD

Social Media Influencer Perceived Source Credibility Scale Validation and Consumer Attitudes Toward the Brand: An Exploratory Study in Urban India

This study explores the relationship between social media influencers (SMIs) perceived source credibility and the formation of brand attitudes of their followers from an urban Indian sample. SMIs have become a channel in shaping consumers’ brand perceptions for products and services across multiple industries worldwide. Using survey data from India, this research delves into the dimensions of SMI perceived source credibility and attitudes towards the brand. A confirmatory factor analysis (CFA) validated the concept that SMI perceived source credibility is a second order construct that is comprised of SMI perceived expertise, goodwill and trustworthiness. Also, that partial least squares structural equation modeling (PLS-SEM) suggests that SMI perceived source credibility is positively related to followers’ brand attitudes in India. These findings complement Hofstede Insights on cultural theory and suggest that culture plays an important role in determining the mechanics of influencer marketing

The Impact of the Social Media Influencer Power on Consumer Attitudes toward the Brand: The Mediating/Moderating Role of Social Media Influencer Source Credibility

This paper presents a conceptual model of the impact of social media influencer power on consumer attitudes toward a brand. The research uses naïve theories of social influence, consumer socialization theory and market signaling theory to support the contention that social media influencer power will impact consumer brand attitudes. However, the impact of the social media influencer power on consumer brand attitudes is posited to be mediated and/or moderated by the social media influencer source credibility. In turn, the social media influencer source credibility is modeled as being positively related to the social media influencer’s expertise/competence with respect to the product, the social media influencer’s goodwill toward the consumer, and the social media influencer’s trustworthiness

Molecular species delimitation of a symbiotic fig-pollinating wasp species complex reveals extreme deviation from reciprocal partner specificity

Background: Symbiotic relationships have contributed to major evolutionary innovations, the maintenance of fundamental ecosystem functions, and the generation and maintenance of biodiversity. However, the exact nature of host/symbiont associations, which has important consequences for their dynamics, is often poorly known due to limited understanding of symbiont taxonomy and species diversity. Among classical symbioses, figs and their pollinating wasps constitute a highly diverse keystone resource in tropical forest and savannah environments. Historically, they were considered to exemplify extreme reciprocal partner specificity (one-to-one host-symbiont species relationships), but recent work has revealed several more complex cases. However, there is a striking lack of studies with the specific aims of assessing symbiont diversity and how this varies across the geographic range of the host. Results: Here, we use molecular methods to investigate cryptic diversity in the pollinating wasps of a widespread Australian fig species. Standard barcoding genes and methods were not conclusive, but incorporation of phylogenetic analyses and a recently developed nuclear barcoding gene (ITS2), gave strong support for five pollinator species. Each pollinator species was most common in a different geographic region, emphasising the importance of wide geographic sampling to uncover diversity, and the scope for divergence in coevolutionary trajectories across the host plant range. In addition, most regions had multiple coexisting pollinators, raising the question of how they coexist in apparently similar or identical resource niches. Conclusion: Our study offers a striking example of extreme deviation from reciprocal partner specificity over the full geographical range of a fig-wasp system. It also suggests that superficially identical species may be able to co-exist in a mutualistic setting albeit at different frequencies in relation to their fig host’s range. We show that comprehensive sampling and molecular taxonomic techniques may be required to uncover the true structure of cryptic biodiversity underpinning intimate ecological interactions

The Relationships Between Prosocial Consumer Behavior, Consumer Resilience, Consumer Risk Taking Propensity and Consumer Hoarding During COVID-19

The Relationships Between Prosocial Consumer Behavior, Consumer Resilience, Consumer Risk Taking Propensity and Consumer Hoarding During COVID-1