Examinando por Autor "Aldana, Marcela"
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Ítem Artificial Light at Night (ALAN) causes size-dependent effects on intertidal fish decision-making(Elsevier, 2023-08) Pulgar, José; Manríquez, Patricio H.; Widdicombe, Stephen; García-Huidobro, Roberto; Quijón, Pedro A.; Carter, Mauricio; Aldana, Marcela; Quintanilla-Ahumada, Diego; Duarte, CristianArtificial Light at Night (ALAN) alters cycles of day and night, potentially modifying species' behavior. We assessed whether exposure to ALAN influences decision-making (directional swimming) in an intertidal rockfish (Girella laevisifrons) from the Southeastern Pacific. Using a Y-maze, we examined if exposure to ALAN or natural day/night conditions for one week affected the number of visits and time spent in three Y-maze compartments: dark and lit arms (“safe” and “risky” conditions, respectively) and a neutral “non-decision” area. The results showed that fish maintained in natural day/night conditions visited and spent more time in the dark arm, regardless of size. Instead, fish exposed to ALAN visited and spent more time in the non-decision area and their response was size-dependent. Hence, prior ALAN exposure seemed to disorient or reduce the ability of rock fish to choose dark conditions, deemed the safest for small fish facing predators or other potential threats. © 2023 Elsevier Ltd.Ítem Host-parasite dialogue: fecundity compensation mechanisms of Fissurella crassa(Frontiers Media SA, 2023) García-Huidobro, M. Roberto; Reyes, Miguel; Fuentes, Nelson Caro; Bruna, Tamara; Guzmán-Rivas, Fabián; Urzúa, Ángel; Pulgar, José; Aldana, MarcelaParasites can alter the reproductive performance of their hosts, and to avoid or mitigate the resulting fitness loss, hosts may increase their current reproductive output to compensate for the future loss due to the parasitic infection. Fecundity compensation can be exploited by parasites for their own transmission (exploitation of host compensatory responses by parasites). However, this phenomenon has rarely been reported in second intermediate hosts of trematodes and its mechanisms and consequences largely unexplored. Along the east coast of the South Pacific, the second intermediate host, the mollusk Fissurella crassa, has been observed to display higher muscular foot, greater shell length and weight, and a higher gonadosomatic index when parasitized by metacercariaes of Proctoeces humboldti compared to non-parasitized hosts. In this study, we examined the histology, biochemistry (glucose, lipids, and proteins), and levels of sex hormones (estradiol and progesterone) in both parasitized and non-parasitized female individuals of F. crassa. Our findings revealed that the gonad of parasitized limpets had a higher density of oocytes, but these had a smaller individual area. Additionally, the gonadal tissue of parasitized limpets exhibited lower glucose content but higher lipid content. Notably, the levels of progesterone increased with parasite intensity. These results suggest that F. crassa possesses the ability to compensate for the negative effects of parasites by increasing the number of oocytes through biochemical and hormonal mechanisms. Our study contributes to the limited research on the impact of metacercariae on the reproduction of second intermediate hosts. Furthermore, we discuss how these changes in parasitized limpets could benefit parasite transmission. Copyright © 2024 García-Huidobro, Reyes, Fuentes, Bruna, Guzmán-Rivas, Urzúa, Pulgar and Aldana.Ítem Impact of predators and resource abundance levels on physiological traits of Fissurella crassa (Archeogastropoda)(UNIV AUTONOMA METROPOLITANA-IZTAPALAPA, 2015) García-Huidobro, M. Roberto; Pulgar Águila, José Miguel; Pulgar Águila, Victor Manuel; Aldana, MarcelaThe effects of predators on the density of prey and their resources have been widely studied; however, there is little evidence on the effects of the predators in conjunction with the availability of resources on the traits of the prey, which could affect foraging activities. In this study, the physiological state and the escape response of the intertidal herbivore Fissurella crassa were evaluated in two sites which differ in terms of the abundance of its predator Heliaster helianthus. The results suggest that the escape response of F. crassa in the site with greater predator density and lower resource availability could require a better body condition that is compensated with increments in foraging. The results highlight the need to address the physiological perspective in community ecology in order to understand the interactions within these communities.Ítem Upper thermal limits and risk of mortality of coastal Antarctic ectotherms(Frontiers Media S.A., 2023-01) Carter, Mauricio J.; García-Huidobro, M. Roberto; Aldana, Marcela; Rezende, Enrico L.; Bozinovic, Francisco; Galbán-Malagón, Cristóbal; Pulgar, José M.Antarctic marine animals face one of the most extreme thermal environments, characterized by a stable and narrow range of low seawater temperatures. At the same time, the Antarctic marine ecosystems are threatened by accelerated global warming. Determining the upper thermal limits (CTmax) is crucial to project the persistence and distribution areas of the Antarctic marine species. Using thermal death time curves (TDT), we estimated CTmax at different temporal scales from 1 minute to daily and seasonal, the predict vulnerability to the current thermal variation and two potential heatwave scenarios. Our results revealed that CTmax at 1 min are far from the temperature present in the marine intertidal area where our study species, showing Echinoderm species higher CTmax than the Chordata and Arthropods species. Simulations indicated that seasonal thermal variation from the intertidal zone contributed to basal mortality, which increased after considering moderate scenarios of heatwaves (+2°C) in the Shetland Archipelago intertidal zone. Our finding highlighted the relevance of including exposure time explicitly on the CTmax estimates, which deliver closer and more realistic parameters according to the species that may be experiencing in the field. Copyright © 2023 Carter, García-Huidobro, Aldana, Rezende, Bozinovic, Galbán-Malagón and Pulgar.