Comparative Dating Of Attine Ant And Lepiotaceous Cultivar Phylogenies Reveals Coevolutionary Synchrony And Discord

The mutualistic symbiosis between fungus-gardening ants and their cultivars has made fundamental contributions to our understanding of the coevolution of complex species interactions. Reciprocal specialization and vertical symbiont cotransmission are thought to promote a pattern of largely synchronous coevolutionary diversification in attines. Here we test this hypothesis by inferring the first time-calibrated multigene phylogeny of the lepiotaceous attine cultivars and comparing it with the recently published fossil-anchored phylogeny of the attine ants. While this comparison reveals some possible cases of synchronous origins of ant and fungal clades, there were a number of surprising asynchronies. For example, leaf-cutter cultivars appear to be significantly younger than the corresponding ant genera. Similarly, a clade of fungi interacting with primitive fungus-gardening ants-thought to be ancestral to the more derived leaf-cutter symbionts-appears instead to be a more recent acquisition from free-living stock. These macroevolutionary patterns are consistent with recent population-level studies suggesting occasional acquisition of novel cultivar types from environmental sources and horizontal transmission of cultivars between different ant species. Horizontal transmission events, even if rare, appear to form loose ecological connections between diffusely coevolving ant and fungus lineages that permit punctuated changes in the topology of the mutualistic ant-fungus interaction network.Integrative Biolog

Opinion Leaders as Brand Advocates in the Medical Industry – How Medical Professionals Perceive Source Credibility and Company Affiliations

Opinion leaders are experts in their domain of interest that share their experience with others. Opinion seekers, on the other hand, value the opinion leader’s knowledge and use them as a source of information to form an opinion about a service or a product. Marketers in the healthcare industry have recognized this information flow and have begun to use leading experts as a valuable third party who can take over the role of brand advocates or endorsers of a particular product. This research examines the marketing concept of opinion leaders advocating a product and persuading medical professionals. In two experimental studies, the influence of opinion leaders on medical students and practicing physicians and their perceived credibility of the message, as well as their attitude towards the company, is examined. The second focus of this research is how medical professionals cope with this form of persuasion attempt and whether their persuasion knowledge is activated. The influence on medical students and physicians through a peer expert - a skilled expert without any public recognition – represents the point of comparison in both studies. The results demonstrate that there are no significant differences in terms of perceived credibility between peer experts and opinion leaders, and that there are no differences regarding their influence on message credibility or attitude toward the company either. Moreover, disclosing company affiliations lead to the correction of attitudes toward the company. However, disclosing conflicts of interest can also be beneficial as it boosts the credibility of the source and helps to increase the perceived credibility of the corporation

Experimentally Increased Incubation Temperature Affects Posthatching Development, Offspring Begging and Parental Care, and Nestling Survival in Three Species of Wild Bird

It is now widely accepted that recent climatic changes have had a causal effect on changing avian life histories. However, evidence for this is largely observational, whereas cause-and-effect inference requires an experimental approach. Here, we assess effects of experimentally increased temperature during incubation on posthatching development in three species of wild songbird, the Carolina chickadee (Poecile carolinensis), Carolina wren (Thryothorus ludovicianus), and prothonotary warbler (Protonotaria citrea). Increased incubation temperatures (i) reduced the duration of the incubation and nestling periods, (ii) reduced posthatching begging for food by nestlings, and (iii) reduced posthatching survival in Carolina chickadees and prothonotary warblers, while nestling Carolina wrens had similar survival but reduced pre-fledging mass. Our results suggest that increasing environmental temperature affect fitness in wild populations in generally negative but species-specific ways, and induce life-history changes including the duration of development and the classic trade-off parents face between the size and number of offspring