http://folia.paru.cas.cz This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Temporal variation in infection levels and reproductive traits of the acanthocephalan Pseudoleptorhynchoides lamothei in the blue sea catfsh Ariopsis guatemalensis (Günther, 1864) Dolores I. Carpio-Hernández 1 , Juan Violante-González 1* , Scott Monks 2 , Agustín A. Rojas-Herrera 1 , Sergio García-Ibáñez 1 , Jeiri Toribio-Jiménez 3 , Himmer Castro-Mondragón 1 1 Facultad de Ecología Marina, Universidad Autónoma de Guerrero, Acapulco, Guerrero, México; 2 Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, México; 3 Centro de Investigaciones Biológicas, Universidad Autónoma del Estado de Hidalgo, Pachuca, Hidalgo, México Abstract: Current data on reproductive biology and population dynamics of the acanthocephalans are scarce mainly in regions from the tropical Pacifc. An analysis was done to identify possible factors that infuence variation in infection levels of the acanthocephalan Pseudoleptorhynchoides lamothei Salgado-Maldonado, 1976 in its fnal host, the blue sea catfsh Ariopsis guatemalensis (Günther, 1864), and describe its main reproductive traits. A total of 1,094 A. guatemalensis were collected from Tres Palos Lagoon from August 2014 to December 2015. Prevalence of P. lamothei varied from 1.47% to 38.33%, and mean abundance from 0.03 to 4.44 helminths per examined host. In female P. lamothei relative fecundity increased with total length. Temporal variations in P. lamothei infection levels were attributed mainly to changes in host feeding and reproductive behaviour in response to local environmental factors as climatic season, and variations in water temperature. Keywords: helminths, dynamics, brackish water fsh, Tres Palos Lagoon, Mexico. Research Article Address for correspondence: J. Violante-González, Facultad de Ecología Marina. Gran Vía Tropical Núm. 20, Fracc. Las Playas, C. P. 39390, Univer- sidad Autónoma de Guerrero, Acapulco, Guerrero, México. Email: viojuang@yahoo.com.mx. Institute of Parasitology, Biology Centre CAS Folia Parasitologica 2020, 67: 012 doi: 10.14411/fp.2020.012 The acanthocephalans are a highly successful helminth parasite group which uses all classes of vertebrates as fnal host. Adult acanthocephalans are endoparasites and live in the gastrointestinal tract of all aquatic vertebrate groups, and even some terrestrial organisms such as mammals and birds. All aspecies of Acanthocephala have an indirect life cycle, with an arthropod as an intermediate host (Cromp- ton and Nickol 1985, Aznar et al. 2001, Kennedy 2006, Salgado-Maldonado and Amin 2009). Thorough descriptions of the biology of several species of Acanthocephala are available mainly for temperate re- gions (Crompton and Nickol 1985, Amin 1975, 1985a, b, 1987), but information on these helminths in tropical re- gions is very scarce. In Mexico, the studies done to date on acanthocephalans have mainly been taxonomic descrip- tions (Salgado-Maldonado 1976, Salgado-Maldonado et al. 2010, Monks et al. 2011), or checklists of these hel- minths in wild vertebrates (Salgado-Maldonado and Amin 2009, García-Prieto et al. 2010). Relatively few studies have focused on aspects of ac- anthocephalan ecology or life cycle (Monks et al. 2009, Alcántara-Escalera et al. 2013, García-Varela et al. 2013, Violante-González et al. 2017a, b). Temporal variation in the infection levels of some acanthocephalan species from tropical or subtropical regions has been linked to season- al changes in environmental conditions (e.g., between dry and rainy seasons) (Brasil-Sato and Pavanelli 1999, Vio- lante-González et al. 2009), as well as to temporal changes in host feeding and reproductive behaviour (Brasil-Sato and Pavanelli 1999, Violante-González et al. 2008, 2009, 2017a). Pseudoleptorhynchoides lamothei Salgado-Maldonado 1976 is an acanthocephalan parasite of fresh- or brackish water fsh that has been reported from many locations in Mexico (Violante-González et al. 2007, García-Varela and González-Oliver 2008). In coastal lagoons on the Pacifc coast of Mexico, this acanthocephalan infects several fsh species, but only matures in the blue sea catfsh Ariopsis guatemalensis (Günther, 1864) (see Violante-González et al. 2007). Although data does exist on P. lamothei infection lev- els in fsh from Tres Palos Lagoon (Violante-González et al. 2007, 2009), no study has yet been done of this acan- thocephalan during a complete annual cycle in this coastal lagoon. In addition, no description has been made of its main reproductive traits. The objectives of the present