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Darcie Marquitti, F. M.

Publications and source records attributed to Darcie Marquitti, F. M..

3 recordsLinked to original sources

POLLINATOR GROOMING BEHAVIOR ALTERS POLLEN LANDSCAPES ON BEES BODIES AND INCREASES POLLEN CARRYOVER TO OTHER FLOWERS

Pollen participates both as the carrier of male gametes in the reproduction of flowering plants and as a key resource exploited by floral visitors, especially bees. Pollinator behavior significantly alters the patterns of pollen removal and deposition, often called pollen fates. To date, few theoretical investigations have attempted to jointly model patterns of pollen transfer and pollinator behavior, and empirical studies are restricted to species to which pollen movement can be tracked. Here we use a spatially explicit agent-based modeling approach, to determine how bee grooming behavior may alter pollen fates and affect plant reproduction. Specifically, we asked whether pollen mixing and removal during pollen grooming may change the "pollen landscape" on a bees body consequently affecting both pollen export by the anthers and deposition onto stigmas. Our model shows that both mixing and removal behaviors restructure the "pollen landscape" on the bees body, increasing pollen carryover (deposition in consecutive visits), and increasing pollen diversity (number of pollen donors) onto stigmas in sequential flower visits. Our results counterintuitively show that pollen grooming may have a positive effect on both male and female finesses during plant reproduction.

ecology↗

Effect of host-switching on the eco-evolutionary patterns of parasites

AO_SCPLOWBSTRACTC_SCPLOWIncreasing empirical evidence has revealed that host-switching are common in the history of parasites. Still, few have explored how the evolutionary histories of hosts might influence such switches and then the evolution of parasites. Here, we investigated how the intensity of host-switching, assumed to depend on the phylogenetic distance between hosts, affects the ecological and evolutionary patterns of parasite species. We developed an individual-based model where parasites can explore and colonise hosts under variable host-switching intensity and have evolution driven by mutation, genetic drift, and mating restriction. We hypothesised that our model can reproduce ecological and evolutionary patterns of empirical communities, characterised by turnover among host species and tree imbalance, respectively. We found an optimum range of host-switching intensity that can predict similar patterns as those observed in the empirical studies, validating our hypothesis. Our results showed that the turnover decreased as the host-switching intensity increased with low variation among the model replications. On the other hand, the tree imbalance had not a monotonic tendency but a wide variation. These results revealed that while the tree imbalance is a sensitive metric to stochastic events, the turnover may be a proxy for host switching. Furthermore, local empirical studies corresponded to higher host-switching intensity when compared to regional studies, highlighting that spatial scale is probably the crucial limitation of host-switching.

ecology↗

Reticulate evolution in a neutral model: speciation, extinctions, and hybridizations

Evolution is usually pictured as a tree where ancient species branch into new ones and eventually disappear. In this simplified view, the balance between speciation and extinction fully determines the diversity of life. Hybridization, how-ever, introduces another level of complexity, allowing neighboring branches of the tree to interact, mixing their genetic content. This generates further diversity leading to reticulated phylogenetic trees. In this paper we study processes of speciation, extinction and hybridization using a genetically and spatially explicit neutral model of diversification. Speciation, extinction and hybridization events are tracked throughout the evolutionary process leading to complete and exact phylogenetic trees. We found that genome size played a key role in these processes, increasing the extinction rate and decreasing the hybridization rate. In our simulations, hybridization after one speciation event occurred throughout the evolutionary process but hybridization after two speciation events was only observed during the initial radiation. Most hybridization occurred between relatively abundant species, discarding lack of sexual partners or small population sizes as potential causes. We found that hybridization occurred mostly because of opportunity (genetic similarity and spatial proximity) between recently branched species, when the number of accumulated mutations is not yet too large.

evolutionary biology↗