Search results for "Asexual"

Population and reproductive dynamics of the polychaete Pygospio elegans in a boreal estuary complex

2016

Pygospio elegans is an opportunistic, wide-spread spionid polychaete that reproduces asexually via fragmentation and can produce benthic and pelagic larvae, hence combining different developmental modes in one species. We documented the density, size distribution, and reproductive activity of P. elegans at four sites in the Danish Isefjord-Roskilde Fjord estuary complex, where all modes of reproduction were reported. We compared population dynamics of this species to environmental parameters such as salinity, temperature, and sediment characteristics (grain size, sorting, porosity, water content, organic content, C/N). We observed that new cohorts—resulting either from sexual or asexual rep…

Settlement dynamics and recruitment responses of Mediterranean gorgonians larvae to different crustose coralline algae species

2020

International audience; Sessile marine species such as Anthozoans act as ecosystem engineers due to their three-dimensional structure. Gorgonians, in particular, can form dense underwater forests that give shelter to other species increasing local biodiversity. In the last decades, several Mediterranean gorgonian populations have been affected by natural and anthropogenic impacts which drastically reduced their size. However, some species showed unexpected resilience, mainly due to the supply of new individuals. To understand the mechanisms underlying recovery processes, studies on the first life history stages (i.e. larval dispersal, settlement and recruitment) are needed. In tropical cora…

2021

Fictosexuality, fictoromance, and fictophilia are terms that have recently become popular in online environments as indicators of strong and lasting feelings of love, infatuation, or desire for one or more fictional characters. This article explores the phenomenon by qualitative thematic analysis of 71 relevant online discussions. Five central themes emerge from the data: (1) fictophilic paradox, (2) fictophilic stigma, (3) fictophilic behaviors, (4) fictophilic asexuality, and (5) fictophilic supernormal stimuli. The findings are further discussed and ultimately compared to the long-term debates on human sexuality in relation to fictional characters in Japanese media psychology. Contexts f…

Soil fungi invest into asexual sporulation under resource scarcity, but trait spaces of individual isolates are unique

2022

During the last few decades, a plethora of sequencing studies provided insight into fungal community composition under various environmental conditions. Still, the mechanisms of species assembly and fungal spread in soil remain largely unknown. While mycelial growth patterns are studied extensively, the abundant formation of asexual spores is often overlooked, though representing a substantial part of the fungal life cycle relevant for survival and dispersal. Here, we explore asexual sporulation (spore abundance, size and shape) in 32 co-occurring soil fungal isolates under varying resource conditions, to answer the question whether resource limitation triggers or inhibits fungal investment…

Jealousy at work: The role of rivals’ characteristics

2018

The present study examined rival characteristics that may evoke jealousy in the workplace, differences between men and women in this regard, and the relationship between jealousy responses and intrasexual competitiveness and social comparison orientation. Participants were 426 male and female employees. By means of a questionnaire, participants were presented with a jealousy-evoking scenario after which jealousy responses to 24 rival characteristics were assessed. Findings showed that a rival's social communal attributes evoked highest levels of jealousy, and that, compared to men, women reported more jealousy in response to a rival's physical attractiveness. Overall, as individuals had hig…

Do Transgender People Respond According to Their Biological Sex or Their Gender Identity When Confronted With Romantic Rivals?

2019

This study examined the hypothesis that gender identity and biological sex represent independent modules and that transgender individuals respond to romantic rivals in line with their gender identity and not with their biological sex. Additionally, associations of jealousy with intrasexual competitiveness (ISC) and social comparison orientation (SCO) were explored. A total of 134 male-to-female and 94 female-to-male transgender individuals from Greater Buenos Aires, Argentina, responded to a questionnaire. In line with the predictions, female-to-male transgender individuals experienced more jealousy than male-to-female transgender individuals in response to a physically dominant rival, whe…

Sex in an uncertain world: environmental stochasticity helps restore competitive balance between sexually and asexually reproducing populations

2014

Like many organisms, individuals of the freshwater ostracod species Eucypris virens exhibit either obligate sexual or asexual reproductive modes. Both types of individual routinely co-occur, including in the same temporary freshwater pond (their natural habitat in which they undergo seasonal diapause). Given the well-known two-fold cost of sex, this begs the question of how sexually reproducing individuals are able to coexist with their asexual counterparts in spite of such overwhelming costs. Environmental stochasticity in the form of 'false dawn' inundations (where the first hydration is ephemeral and causes loss of early hatching individuals) may provide an advantage to the sexual subpop…

Pythium segnitiumsp. nov., isolated from the Canary Islands – its taxonomy, ITS region of rDNA, and comparison with related species

2002

Pythium segnitium (CI-44) was isolated from some soil samples taken in the Canary Islands (Spain). This new species is a slow-growing fungus and is perfectly adapted to terrestrial habitat. It belongs to the group of Pythium that have smooth-walled oogonia, mostly hypogynous antheridia, and plerotic oospores. The fungus lacks sporangia, zoospores, and hyphal bodies are rarely formed. Thus the asexual reproduction, which is so common for fungi and especially for the aquatic ones, is completely lacking in this case. However the fungus reproduces sexually by the formation of oogonia, antheridia and oospores plentifully. The taxonomic description of this fungus, the nucleotide sequence of the i…

Salinity effects on asexual reproduction of Carybdea sp. (Cnidaria: Cubozoa)

2014

6 pages, 2 figures, 1 table, supplementary data http://plankt.oxfordjournals.org/content/36/2/585/suppl/DC1

The red tooth hypothesis: A computational model of predator-prey relations, protean escape behavior and sexual reproduction

2009

This paper presents an extension of the Red Queen Hypothesis (hereafter, RQH) that we call the Red Tooth Hypothesis (RTH). This hypothesis suggests that predator-prey relations may play a role in the maintenance of sexual reproduction in many higher animals. RTH is based on an interaction between learning on the part of predators and evolution on the part of prey. We present a simple predator-prey computer simulation that illustrates the effects of this interaction. This simulation suggests that the optimal escape strategy from the prey's standpoint would be to have a small number of highly reflexive, largely innate (and, therefore, very fast) escape patterns, but that would also be unlearn…