We consider a two-competitor/one-prey model in which both competitors exhibit a general functional response and one of the competitors exhibits a density-dependent mortality rate. It is shown that the two competitors can coexist upon the single prey. As an example, we consider a two-competitor/one-prey model with a Holling II functional response. Our results demonstrate that density-dependent mortality in one of the competitors can prevent competitive exclusion. Moreover, by constructing a Liapunov function, the system has a globally stable positive equilibrium.
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http://dx.doi.org/10.1016/j.crvi.2007.10.004 | DOI Listing |
Bull Entomol Res
January 2025
Environmental Sciences Graduate Program, Community University of the Chapecó Region (Unochapecó), Chapecó, SC, Brazil.
Mosquitoes, particularly , pose significant public health risks by transmitting diseases like dengue, zika and chikungunya. var. (BTI) is a crucial larvicide targeting mosquitoes while sparing other organisms and the environment.
View Article and Find Full Text PDFPLoS One
December 2024
Baruch Marine Field Laboratory, University of South Carolina, Georgetown, SC, United States of America.
Ecology
January 2025
Department of Integrative Biology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Understanding how demographic parameters change with density is essential for predicting the resilience of small populations. We use long-term, individual-based life history data from an isolated population of the Critically Endangered Northern Muriqui (Brachyteles hypoxanthus) inhabiting a 1000-ha protected forest to evaluate density-dependent demographic rates before and after an abrupt population decline. We found no effect of density on fertility or birth sex ratio, but mortality rates increased linearly with log density over the 33 years of population growth (1983-2015) and the subsequent 7 years of population decline (2016-2022).
View Article and Find Full Text PDFJ Exp Zool A Ecol Integr Physiol
January 2025
Economic Entomology Department, Faculty of Agriculture, Mansoura University, Mansoura, Egypt.
J Theor Biol
December 2024
Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, 02142, MA, USA. Electronic address:
Although demographic studies have failed to find evidence of aging in certain animal species, classic evolutionary theories of aging struggle to explain how evolution could favor agelessness in such cases. Here, we develop mathematical models of the disposable soma theory to identify conditions in which agelessness would be evolutionarily favored. For any given type of damage that could accumulate and cause age-accelerating mortality risk, we find that evolution could select for its complete removal if the mortality risk it poses is severe enough and its repair does not pose too large of a penalty to reproduction.
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