Abstract
Interspecific competition is a fundamental process affecting community structure and evolution of interacting species. Besides direct competition, this process is also mediated by shared enemies, which can change the outcome of competition dramatically. However, previous studies investigating interactions between competing species and their parasites (parasite-mediated competition) completely overlooked the effect of ‘sperm’ parasites (i.e. sperm-dependent parthenogens or pseudogams) on competition. These organisms originate by interspecific hybridization, produce clonal gametes, but exploit parental species for their own reproduction, being therefore analogous to classical parasites. Here we use the reaction-diffusion model and show that pseudogams alter the outcome of interspecific competition significantly. They may either slow down competitive exclusion of the inferior competitor or even turn the outcome of competition between the species. Asexual organisms may thus have unexpectedly strong impact on community structure, and have more significant evolutionary potential than was previously thought.
Highlights
The diversity of extant organisms results from interplay of various intra- and interspecific interactions including competition, parasitism, hybridisation
To investigate the multilateral interactions among sexual species and their pseudogamous hybrids, we use a model based on the Lotka-Volterra equations, which have commonly been applied to study both interspecific competition and sexual-pseudogamous systems[39,40,41]
In systems where sexual and sperm-dependent asexual forms interact, the sexual species, which is more resistant to pseudogams, gains the advantage in the interspecific competition even if it normally appears as the inferior competitor
Summary
The diversity of extant organisms results from interplay of various intra- and interspecific interactions including competition, parasitism, hybridisation. Pseudogams represent a special puzzle in evolution as they exhibit the disadvantages of both sexual and asexual reproductive modes[6], i.e. they lack effective recombination but simultaneously depend on obtaining a mating partner. Due to these properties, pseudogamous systems have commonly been regarded as entities with a rather ephemeral evolutionary potential[7]. It is noteworthy that sexual sperm-donors, analogously to the hosts of ‘classical’ parasites, employ various mechanisms to increase their ‘immunity’ Such countermeasures against pseudogamy include niche segregation[20], spatial differentiation[21] and behavioural adaptation[22]. The mating preference of sexual males for their own females, might represent a prominent mechanism for stabilizing the coexistence of sexuals and pseudogams[23,24,25]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
