Biomaterial Database

Testing sex ratio theory with the malaria parasite Plasmodium mexicanum in natural and experimental infections. 2014

Allison T Neal, and Jos J Schall

Department of Biology, University of Vermont, Burlington, Vermont 05405. aneal@uvm.edu.

The malaria parasite (Plasmodium) life history accords well with the assumptions of local mate competition (LMC) of sex ratio theory. Within a single meal of the blood-feeding vector, sexually dimorphic gametocyte cells produce gametes (females produce one, males several) that mate and undergo sexual recombination. The theory posits several factors drive the Plasmodium sex ratio: male fecundity (gametes/male gametocyte), number and relative abundance of parasite clones, and gametocyte density. We measured these traits for the lizard malaria parasite, Plasmodium mexicanum, with a large sample of natural infections and infections from experiments that manipulated clonal diversity. Sex ratio in single-clone infections was slightly female-biased, but matched predictions of theory for this low-fecundity species. Sex ratio was less female-biased in clonally diverse infections as predicted by LMC for the experimental, but not natural infections. Gametocyte density was not positively related to sex ratio. These results are explained by the P. mexicanum life history of naturally low clonal diversity and high gametocyte production. This is the first study of a natural malaria system that examines all traits relevant to LMC in individual vertebrate hosts and suggests a striking example of sex ratio theory having significance for human public health.

UI	MeSH Term	Description	Entries
D008116	Lizards	Reptiles within the order Squamata that generally possess limbs, moveable EYELIDS, and EXTERNAL EAR openings, although there are some species which lack one or more of these structures.	Chameleons,Geckos,Chameleon,Gecko,Lizard
D008288	Malaria	A protozoan disease caused in humans by four species of the PLASMODIUM genus: PLASMODIUM FALCIPARUM; PLASMODIUM VIVAX; PLASMODIUM OVALE; and PLASMODIUM MALARIAE; and transmitted by the bite of an infected female mosquito of the genus ANOPHELES. Malaria is endemic in parts of Asia, Africa, Central and South America, Oceania, and certain Caribbean islands. It is characterized by extreme exhaustion associated with paroxysms of high FEVER; SWEATING; shaking CHILLS; and ANEMIA. Malaria in ANIMALS is caused by other species of plasmodia.	Marsh Fever,Plasmodium Infections,Remittent Fever,Infections, Plasmodium,Paludism,Fever, Marsh,Fever, Remittent,Infection, Plasmodium,Plasmodium Infection
D010961	Plasmodium	A genus of protozoa that comprise the malaria parasites of mammals. Four species infect humans (although occasional infections with primate malarias may occur). These are PLASMODIUM FALCIPARUM; PLASMODIUM MALARIAE; PLASMODIUM OVALE, and PLASMODIUM VIVAX. Species causing infection in vertebrates other than man include: PLASMODIUM BERGHEI; PLASMODIUM CHABAUDI; P. vinckei, and PLASMODIUM YOELII in rodents; P. brasilianum, PLASMODIUM CYNOMOLGI; and PLASMODIUM KNOWLESI in monkeys; and PLASMODIUM GALLINACEUM in chickens.	Plasmodiums
D002140	California	State bounded on the east by Nevada and Arizona, on the south by Mexico and the Pacific Ocean on the south and west, and on the north by Oregon.
D005298	Fertility	The capacity to conceive or to induce conception. It may refer to either the male or female.	Fecundity,Below Replacement Fertility,Differential Fertility,Fecundability,Fertility Determinants,Fertility Incentives,Fertility Preferences,Fertility, Below Replacement,Marital Fertility,Natural Fertility,Subfecundity,World Fertility Survey,Determinant, Fertility,Determinants, Fertility,Fertility Determinant,Fertility Incentive,Fertility Preference,Fertility Survey, World,Fertility Surveys, World,Fertility, Differential,Fertility, Marital,Fertility, Natural,Preference, Fertility,Preferences, Fertility,Survey, World Fertility,Surveys, World Fertility,World Fertility Surveys
D005854	Germ Cells	The reproductive cells in multicellular organisms at various stages during GAMETOGENESIS.	Gamete,Gametes,Germ-Line Cells,Germ Line,Cell, Germ,Cell, Germ-Line,Cells, Germ,Cells, Germ-Line,Germ Cell,Germ Line Cells,Germ Lines,Germ-Line Cell
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012744	Sex Ratio	The number of males per 100 females.	Ratio, Sex,Ratios, Sex,Sex Ratios