Classic depictions of human evolutionary ecology cast Homo as predator and other hominins, including Paranthropus robustus, as prey. Such hypotheses rest on a small number of fossils that exhibit evidence of carnivore predation, including the iconic SK 54 cranium from Swartkrans in South Africa. Here we demonstrate that the SK 54 cranium shares its closest affinities with H. erectus sensu lato rather than P. robustus. Demonstrating that Homo was prey for leopards at Swartkrans weakens the historically significant hypothesis that Homo was better able to avoid predation because of being behaviourally and technologically advanced compared to Paranthropus. Subsequent ideas about hominin palaeobiology derived from this hypothesis warrant reconsideration. SIGNIFICANCE: • The small sample of early Homo from southern Africa is increased by the allocation of the SK 54 cranium to that genus. • Evidence from Swartkrans suggests that Homo was prey for leopards. • Hypotheses concerning the biology, behaviour, and technological capabilities of Homo and P. robustus stemming from Brain's seminal work, The Hunters or the Hunted?, should be reassessed.

Resumen Introducción: Los equinodermos, un componente integral de los ecosistemas marinos en todo el mundo, han captado el interés científico durante siglos. A pesar de esta prolongada atención, el comprender facetas clave como las relaciones tróficas, la composición de la dieta y las relaciones huésped-microbiota todavía representa un desafío utilizando técnicas tradicionales. Sin embargo, los últimos años han sido testigos de un cambio transformador, gracias a la aparición de técnicas moleculares avanzadas, que ofrecen nuevos enfoques para fortalecer los estudios ecológicos en equinodermos. Objetivo: Explorar cómo los avances recientes en herramientas moleculares han impactado la investigación ecológica sobre equinodermos. Específicamente, nuestro objetivo es investigar el potencial de estas herramientas para arrojar luz sobre las interacciones tróficas, la composición de la dieta y la caracterización de las comunidades microbianas intestinales en estos organismos. Métodos: Se utilizó la literatura disponible para aclarar cómo las nuevas técnicas moleculares pueden mejorar los estudios ecológicos. La atención se centra en la dieta, las relaciones tróficas y la microbiota intestinal. Resultados: Tradicionalmente, los estudios del contenido estomacal mediante microscopía compuesta han proporcionado una idea del material ingerido; Sin embargo, a veces una simple visualización ampliada del contenido dietético no permite una identificación exhaustiva de todo el espectro alimentario, ya que está limitado debido a la rápida digestión y maceración de los alimentos dentro del tracto digestivo del equinodermo. El uso de metabarcoding de ADN, dirigidos a regiones específicas del ADN, como el gen COI mitocondrial, nos ha permitido mejorar la exactitud y precisión de la caracterización de la dieta al permitir la identificación de presas hasta el nivel de especie o incluso de variante genética, lo que proporciona valiosos resultados sobre preferencias dietéticas específicas. Otro enfoque es el uso de isótopos estables, en particular carbono y nitrógeno, que proporcionan una poderosa herramienta para rastrear el origen y el flujo de nutrientes a través de las redes alimentarias. Al analizar las firmas isotópicas en los tejidos musculares y los alimentos, podemos discernir las fuentes de sus alimentos primarios y obtener información sobre su posición trófica dentro del ecosistema. Por último, una tercera técnica nueva utilizada para dilucidar la caracterización de la comunidad procariótica es la secuenciación del ARNr 16S. Este método nos permite explorar la composición y dinámica de las comunidades microbianas del tracto digestivo. Conclusiones: Esta es una era prometedora para la investigación ecológica sobre equinodermos, donde los avances de las herramientas moleculares han permitido un nivel de detalle sin precedentes, resolviendo desafíos de larga data en la comprensión de sus interacciones tróficas, composición de la dieta y relaciones huésped-microbiota, y abriendo nuevas vías de investigación. en estudios ecológicos.

Abstract Introduction: Echinoderms, an integral component of marine ecosystems worldwide, have captivated scientific interest for centuries. Despite this longstanding attention, comprehending key facets such as trophic relationships, diet composition, and host-microbiota relationships still represents a challenge using traditional techniques. Recent years, however, have witnessed a transformative shift, thanks to the emergence of advanced molecular techniques, offering new approaches to strengthen ecological studies in echinoderms. Objective: Explore how recent advancements in molecular tools have impacted ecological research on echinoderms. Specifically, we aim to investigate the potential of these tools to shed light on trophic interactions, diet composition, and the characterization of gut microbial communities in these organisms. Methods: Available literature was used to clarify how novel molecular techniques can improve ecological studies. The focus is diet, trophic relationships, and gut microbiota. Results: Traditionally, studies of stomach contents using compound microscopy have provided an idea of ingested material; nevertheless, sometimes a simple magnified visualization of dietary content does not allow exhaustive identification of the entire food spectrum, as it is limited due to the rapid digestion and maceration of food items within the echinoderm’s digestive tract. The use of DNA-metabarcoding, targeting specific DNA regions, such as the mitochondrial COI gene, has allowed us to enhance the accuracy and precision of diet characterization by enabling the identification of prey items down to the species or even genetic variant level, providing valuable insights into specific dietary preferences. Another approach is the use of stable isotopes, particularly carbon and nitrogen, which provide a powerful tool to trace the origin and flow of nutrients through food webs. By analyzing the isotopic signatures in muscular tissues and food items, we can discern the sources of their primary food items and gain insights into their trophic position within the ecosystem. Lastly, a third new technique used to elucidate the characterization of the prokaryotic community is 16S rRNA sequencing. This method allows us to explore the composition and dynamics of the digestive tract microbial communities. Conclusions: This is a promising era for ecological research on echinoderms, where advances of molecular tools have enabled an unprecedented level of detail, resolving longstanding challenges in comprehending their trophic interactions, diet composition, and host-microbiota relationships, and opening new avenues of investigation in ecological studies.

Resumo A raposa-vermelha (Vulpes vulpes) é um carnívoro de médio porte que ocorre em diferentes regiões do Paquistão, porém ainda carece de dados científicos sobre sua ecologia e distribuição. O presente estudo investigou o status filogenético e a dieta da raposa-vermelha (V.v. griffithii) que ocorre no Parque Nacional de Ayubia, Paquistão. Por meio de armadilhas fotográficas e análises moleculares, confirmamos a ocorrência de raposa-vermelha na área de estudo. Com base no citocromo B mitocondrial (304 bp) e amostragem limitada, quase todas as raposas-vermelhas do Parque Nacional de Ayubia e áreas circundantes do Himalaia se enquadram na linhagem materna holártica, enquanto as raposas-vermelhas encontradas nas planícies do Paquistão fazem parte da linhagem materna basal paleártica. Usando 32 fezes, descobrimos que a dieta da raposa-vermelha compreende 80% de espécies de presas de origem animal (selvagens e domésticas) e 19% de matéria vegetal. As espécies de presas de animais selvagens incluíram a lebre-do-cabo (Lepus capensis) e o esquilo-voador (Pteromyini sp.), que constituíram 17% e 15% da dieta, respectivamente. As raposas-vermelhas consumiam raramente ratos domésticos (Mus musculus), algas do Himalaia (Paguma larvata) e ovelhas (Ovis aries), cada um compreendendo cerca de 6% a 9% da dieta da raposa-vermelha. A espécie de raposa também se alimentava de burros domésticos de forma oportunista. Com base em nossa amostragem, nosso estudo sugere que a raposa-vermelha (V.v. griffithii) que ocorre no Parque Nacional de Ayubia e nas cordilheiras menores do Himalaia pertence à linhagem materna holártica. O estudo também destaca o consumo de sementes de plantas por raposas-vermelhas, indicando que pode desempenhar um papel ecológico importante na dispersão de sementes no Parque Nacional de Ayubia.

Abstract The red fox (Vulpes vulpes) is a medium-sized carnivore that occurs in different regions of Pakistan, however, still lacks scientific data on its ecology and distribution. The current study investigated the phylogenetic status and diet of the red fox (V.v. griffithii) occurring in Ayubia National Park, Pakistan. Through camera trapping and molecular analysis, we confirmed the occurrence of red fox in the study area. Based on mitochondrial cytochrome B (304 bp) and limited sampling, nearly all red foxes of Ayubia National Park and surrounding Himalayan ranges fall within Holarctic maternal lineage, whereas red foxes found in plains of Pakistan are part of the basal Palearctic maternal lineage. Using 32 scats, we found that red fox diet comprises of 80% animal-based prey species (both wild and domestic) and 19% plant matter. The wild animal prey species included Cape hare (Lepus capensis) and flying squirrel (Pteromyini sp.), which constituted 17% and 15% of diet, respectively. Red foxes infrequently consumed House mouse (Mus musculus), Himalayan Palm civet (Paguma larvata) and sheep (Ovis aries), each comprising around 6% to 9% of red fox diet. The fox species also scavenged on domestic donkey opportunistically. Based on our sampling, our study suggests that the red fox (V.v. griffithii) that occurs in Ayubia National Park and across the lesser Himalayan ranges belongs to Holarctic maternal lineage. The study also highlights consumption of plant seeds by red foxes, indicating it may play an important ecological role in seed dispersal in Ayubia National Park.

Resumo O crescimento da população humana é um risco solene para a biodiversidade em nível global. A pressão antrópica maciça e a invasão nos habitats naturais iniciaram o conflito homem-vida selvagem nas áreas rurais. O presente estudo teve como objetivo avaliar o conflito entre humanos e animais selvagens no Parque Nacional Musk Deer (MDNP) de 2013 a 2018. Os resultados revelaram uma estimativa de 241.784 cabeças de gado nômades e 5.589 residenciais pastando em diferentes áreas do MDNP durante a temporada de verão. Um total de 126 cabeças foi depredado por carnívoros durante o período de estudo. A maioria (n = 39) das cabeças de gado foi morta em maio (n = 29). A depredação do gado resultou em perdas econômicas no valor de 3,115 milhões de PKRs (US$ 25.744) para a comunidade de pastores, enquanto os agricultores receberam 1,629 milhões de PKRs (US$ 13.466) perdas devido à invasão de plantações. A maioria (64%) dos entrevistados acredita que o conflito entre humanos e animais selvagens aumentou devido à escassez de alimentos ou presas nos habitats naturais dos carnívoros. A maioria (92%) dos entrevistados não gostou da presença de predadores no MDNP. Esquemas de compensação de perdas podem transformar essa atitude negativa em positiva e aumentar a tolerância com a presença de carnívoros em suas proximidades. Este estudo fornece uma visão sobre o conflito homem-vida selvagem no MDNP e abre caminho para a compreensão do conflito e conservação de espécies carnívoras na área de estudo.

Abstract Growing human population is a solemn risk to biodiversity at a global level. Massive anthropogenic pressure and invasion in the natural habitats initiated the human-wildlife conflict in rural areas. Present study aimed to assess human-wildlife conflict in Musk Deer National Park (MDNP) from 2013 to 2018. Results revealed an estimated 241784 nomadic and 5589 residential livestock heads grazed in different areas of MDNP during the summer season. A total of 126 heads were depredated by carnivores during the study period. Majority (n=39) of livestock heads were killed in May (n=29). Livestock depredation resulted in economic losses worth 3.115 million PKRs (25744 US$) to the herder community while farmers received 1.629 million PKRs (13466 US$) losses due to crop raiding. Most (64%) of the respondents believed human-wildlife conflict heightened due to scarcity of food or prey in the natural habitats of carnivores. Majority (92%) of the respondents did not like the presence of predators in MDNP. Loss compensation schemes could turn this negative attitude into the positive one and increase tolerance about the presence of carnivores in their vicinity. This study provides an insight into the human-wildlife conflict in MDNP and paves a way for understanding the conflict and conservation of carnivore species in the study area.

Resumo As respostas funcionais de larvas de Chrysoperla carnea foram avaliadas em sete diferentes densidades de ninfas de 3º instar de Aphis craccivora e Gynaikothrips ficorum, a fim de descobrir a relação entre as densidades de predadores e suas presas, e sua capacidade de controle biológico de pulgões e tripes. Os resultados revelaram que todos os instares larvais testados de Ch. carnea apresentaram resposta de tipo II em relação à presa. Além disso, os coeficientes de taxa de ataque (a) e tempo de manejo (Th) diferiram entre os vários instares de crescimento do predador e para a espécie de presa. As larvas de 3º instar de Ch. carnea manifestaram a maior taxa de ataque (1,23 e 1,22) nas ninfas de 3º instar de A. craccivora e G. ficorum, respectivamente. Além disso, a maior taxa de predação máxima (Na máx.) (50,00 e 52,63) apresentou-se em ninfas de A. craccivora e G. ficorum, respectivamente, em comparação aos demais tratamentos. Assim, é possível concluir que o Ch. carnea pode ser considerado um agente de biocontrole promissor para o manejo de A. craccivora e G. ficorum.

Abstract The functional responses of Chrysoperla carnea larvae were evaluated at different seven densities of the 3rd instar nymphs of Aphis craccivora and Gynaikothrips ficorum in order to find out the relationship between predator densities and its prey by the, and also to find out their capability for biological control of aphids and thrips. Results revealed that all tested larval instars of Ch. carnea exhibited a type II response in relation to the prey. Moreover, the coefficients of attack rate (a) and handling time (Th) was differed among various growing instars of predator and for the prey species. The 3rd instar larvae of Ch. carnea manifested the highest attacking rate (1.23 and 1.22) on the 3rd instar nymphs of A. craccivora and G. ficorum, respectively. In addition it exhibited the highest maximum predation (Na max) (50.00 and 52.63) on A. craccivora and G. ficorum nymphs, respectively as compared with the other treatments. Accordingly, Ch. carnea could be considered as a promising bio-control agent for A. craccivora and G. ficorum management.

Resumen Introducción: Tlaloc hildebrandi es un killi de agua dulce, endémico del sur de México y bajo amenaza de extinción; el conocimiento de la morfología trófica y la dieta son necesarios para los administradores de la conservación. Objetivo: Analizar y describir la anatomía del esqueleto visceral, la musculatura visceral, el tracto digestivo y las glándulas adyacentes de T. hildebrandi; así como los componentes de su dieta. Métodos: Mediante la técnica del descarnado manual, realizamos la descripción de la anatomía trófica en 20 especímenes adultos de ambos sexos, y el análisis del contenido estomacal en 60 individuos para describir la dieta. Resultados: Como caracteres sobresalientes del esqueleto visceral de T. hildebrandi está la escotadura posterior del premaxilar, la presencia del “cartílago coronoides”, la forma tricúspide de las branquiespinas del primer arco branquial y la presencia del hueso coronomeckeliano; como caracteres de la musculatura visceral sobresalen el origen del músculo retractor dorsalis de los cuatro primeros centros vertebrales, y la división del músculo pharyngoclavicularis externus en dos secciones. Los caracteres notables del tubo digestivo son la ausencia de estómago y de ciegos pilóricos y la presencia de la “válvula intestinal”. Los insectos (IVI = 66.6 %) y ostrácodos (13 % IVI) fueron los componentes dominantes de la dieta de T. hildebrandi; particularmente las larvas y adultos de la familia Chironomidae fueron los insectos más abundantes en la dieta (53 % IVI). Conclusiones: La organización del sistema digestivo de T. hildebrandi corresponde al patrón morfológico general de los Cyprinodontiformes, sin embargo, se registra como nueva información para estos peces, la presencia del cartílago coronoides y la válvula intestinal. Las estructuras de la morfología trófica y los componentes de la dieta nos confirman que T. hildebrandi es un pez carnívoro-insectívoro.

Abstract Introduction: Tlaloc hildebrandi is a freshwater killifish, endemic to Southern Mexico and under threat of extinction; the knowledge of the trophic morphology and diet is needed by conservation managers. Objective: To analyse and describe the anatomy of the visceral skeleton, visceral musculature, digestive tract and its adjoining glands of T. hildebrandi; as well as its diet. Methods: We performed the trophic anatomy on 20 adult specimens of both sexes, through manual dissection; as well as gut content analysis in 60 individuals to describe the diet. Results: As notable characters of the visceral skeleton of T. hildebrandi we found the posterior notch of the premaxillary, the presence of the “coronoid cartilage”, the tricuspid shape of the gill rakers of the first branchial arch, and the presence of the coronomeckelian bone; some outstanding characters of the visceral musculature are the origin of the retractor dorsalis muscle from the first four vertebral centra, and the division of the pharyngoclavicularis externus muscle into two sections. The notable characters of the digestive tube are the absence of stomach and pyloric caeca, and the presence of the “intestinal valve”. Insects (IVI = 66.6 %) and ostracods (13 % IVI) were the dominant prey items of the Tlaloc hildebrandi diet; larvae and adults of the family Chironomidae were the most dominant insects in the diet (53 % IVI). Conclusions: The organization of the digestive system of T. hildebrandi corresponds to the general morphologic pattern of the Cyprinodontiformes; however, we register as new information for these fish, the presence of the “coronoid cartilage” and the “intestinal valve”. The structures of the trophic morphology and the components of the diet, confirms us that T. hildebrandi is a carnivorous-insectivorous fish.

Abstract 26. Echinococcus vogeli originates neotropical polychistic echinococcosis, an emerging zoonotic disease in tropical countries of Central and South America. Its life cycle is adapted to a mandatory relationship between the bush dog (Speothos venaticus) and one of its main prey, the paca (Cuniculus paca), which is, in turn, one of the most consumed species as a source of animal protein in the Peruvian Amazon. The aim of this work was to evaluate the frequency of E. vogeli in pacas hunted for personal consumption by inhabitants in the high basin of the Itaya River. During 2016-2017, subsistence hunters from the communities of Melitón Carbajal, Luz del Oriente, 28 de Enero and Nueva Villa Belén collected liver and lungs of 36 pacas and the liver of a nine-banded armadillo (Dasypus novemcinctus). These organs were analyzed by parasitological, including macroscopic, microscopic-morphometric analysis. The 13.5% (5/37) of the wild mammals collected (paca n=4; nine-banded armadillo n=1) presented polycystic masses in the liver, with rostral hooks of protocystic scolices compatible with E. vogeli. This work contributes to the ecoepidemiological knowledge of new records on the distribution of E. vogeli and confirms the first record of E. vogeli in the nine-banded armadillo in the Peruvian Amazon, reinforcing the need to raise awareness, prevent, monitor, control and expand the search for neotropical echinococcosis and other zoonoses in wildlife and human populations in coexistence, from the “One Health” approach.

Resumen 22. Echinococcus vogeli origina la Equinococosis Neotropical Poliquística, enfermedad zoonótica emergente en países tropicales de Centro y Sur América. Su ciclo natural está adaptado a una relación predador-presa representado principalmente por el perro de monte (Speothos venaticus) y el majaz (Cuniculus paca), que es una de las especies silvestres más consumidas en la Amazonia. El objetivo de este trabajo fue evaluar la frecuencia de E. vogeli en majaces cazados para consumo personal por pobladores de la cuenca alta del Río Itaya, en la Amazonía peruana. Durante el periodo 2016-2017, cazadores de subsistencia de las comunidades de Melitón Carbajal, Luz del Oriente, 28 de Enero y Nueva Villa Belén realizaron la colecta de hígados y pulmones de 36 majaces y el hígado de un armadillo de nueve bandas, (Dasypus novemcinctus). Se realizaron análisis parasitológicos, que incluyó descripciones macroscópicas, microscópicas y morfometría. El 13,5% (5/37) de los mamíferos silvestres colectados (majaz n=4; armadillo de nueve bandas n=1) presentaron masas poliquísticas en hígado, con ganchos rostelares de protoescólices compatibles con E. vogeli. Este trabajo aporta al conocimiento ecoepidemiológico de nuevos registros sobre la distribución de E. vogeli y confirma el primer registro de E. vogeli en armadillo de nueve bandas en la Amazonia peruana, reforzando la necesidad de concientizar, prevenir, monitorear, controlar y ampliar la búsqueda de la equinococosis neotropical y otras zoonosis en fauna silvestre y en poblaciones humanas en coexistencia, desde el enfoque de “Una Salud”.

RESUMO Cleptoparasitas facultativos enfrentam os custos envolvidos no roubo do alimento em troca da compensação pelo valor nutricional do item roubado. Essa interação é pouco conhecida, mas observações anedóticas indicam que aves de rapina podem se beneficiar de sua visão acurada para cleptoparasitar. Reportamos uma tentativa de cleptoparasitismo de um furão-grande, Galictis vittata, por um gavião-branco, Pseudastur albicollis, em uma floresta na Amazônia central brasileira recentemente manejada para corte seletivo de impacto reduzido. Como o furão-grande respondeu agressivamente ao ataque, a tentativa de roubo falhou. O evento foi registrado por uma armadilha fotográfica em uma clareira linear. O ambiente mais aberto pode ter aumentado a habilidade do gavião-branco em encontrar o seu hospedeiro. Eventos de cleptoparasitismo são dificilmente registrados em ambientes florestais. Registros de cleptoparasitismo em florestas tropicais podem não depender apenas do uso intensivo de armadilhas fotográficas, mas também de condições ambientais favoráveis à detecção de possíveis hospedeiros pelo cleptoparasita. roubado conhecida cleptoparasitar furãogrande, furãogrande furão grande, grande vittata gaviãobranco, gaviãobranco gavião branco, branco albicollis reduzido ataque falhou linear hospedeiro florestais fotográficas cleptoparasita

ABSTRACT Facultative kleptoparasites face the risk of trying to steal food resources from competitors. This type of interaction is little known, but anecdotal observations indicate that birds of prey may take advantage of their accurate sight to detect the best opportunities for kleptoparasitism. We recorded a camera trap video of an attempt of kleptoparasitism by the white hawk, Pseudastur albicollis, that tried to steal food from a greater grison, Galictis vittata, in a recently selectively-logged forest site in central Brazilian Amazonia. The attempt was unsuccessful as the greater grison responded aggressively to the attack. The event occurred in a linear clearing, which may have increased the bird’s ability to detect its potential host. Kleptoparasitic interactions are difficult to detect in forest environments. Recording opportunistic kleptoparasitic interactions in tropical forests may not only depend on the increasing use of camera traps, but also on habitat conditions that facilitate the detection of potential hosts. competitors known hawk albicollis vittata selectivelylogged selectively logged Amazonia attack clearing bird s host environments traps hosts

ABSTRACT Background. The control of lionfish in the Tuxpan reef is limited due to a lack of knowledge. In addition to its registration in 2012, there is information on feeding and scattered data on its abundance and size that need to be revised to define local management strategies. Objectives. To determine some population aspects (density, biomass, size distribution) of lionfish and their relationship with environmental variables and prey density in the Tuxpan reef, Veracruz. Methods. 122 censuses were carried out in six depth strata of the reef slopes. In each census, the environment (rugosity, coral cover, wave intensity, and depth) was characterized; the abundance, size, and biomass of lionfish were estimated, as well as the abundance of its potential prey. The information was compared and related to the environmental variables using two scales: slope and depth strata. The size distribution was obtained from 43 fish captured. Results. The density of lionfish in the Tuxpan reef was 24.6 ind/ha and the biomass of 4 440 g/ha. No differences in density and biomass were detected at the slope scale, but analysis by depth strata related density with rugosity in windward (r= 0.81, p= 0.05) and to coral cover (r= 0.76, p= 0.08) in leeward. The abundance of potential prey showed no relationship with lionfish density and biomass. The lionfish population has a size range of 7.4 to 35.6 cm. Conclusions. The lionfish population at Tuxpan reef is represented by juveniles and adults whose density is related at the depth strata scale to rugosity and coral cover.

RESUMEN Antecedentes. El control del pez león en el arrecife Tuxpan está limitado por falta de conocimiento. Además de su registro en 2012, existe información sobre alimentación y datos dispersos sobre su abundancia y talla que son insuficientes para definir las estrategias de manejo local. Objetivos. Determinar algunos aspectos poblacionales (densidad, biomasa, distribución de tallas) del pez león y su relación con las variables ambientales y la densidad de presas en el arrecife Tuxpan, Veracruz. Métodos. Fueron realizados 122 muestreos en seis estratos de profundidad de las pendientes arrecifales. En cada censo, se caracterizó el ambiente (rugosidad, cobertura coralina, oleaje y profundidad) y se estimaron la abundancia, talla y biomasa del pez león, así como la abundancia de sus presas potenciales. La información fue comparada y relacionada con las variables ambientales, usando dos escalas: pendientes y estratos de profundidad. La distribución de tallas se obtuvo a partir de 43 peces capturados. Resultados. La densidad del pez león en el arrecife Tuxpan fue de 24.6 ind/ha y la biomasa de 4 440 g/ha. A escala de pendientes no se detectaron diferencias en la densidad y biomasa, pero el análisis por estratos de profundidad relacionó la densidad con la rugosidad en barlovento (r = 0.81, p = 0.05) y con la cobertura coralina (r = 0.76, p = 0.08) en sotavento. La abundancia de presas potenciales no mostró relación con la densidad y biomasa del pez león. La población de esta especie posee un rango de tallas de 7.4 a 35.6 cm. Conclusiones. La población de pez león en el arrecife Tuxpan está representada por juveniles y adultos cuya densidad se relaciona a escala de estratos de profundidad con la rugosidad y la cobertura coralina.

Resumen En este trabajo se presenta el modelado de un ecosistema sencillo de presas y depredadores, mediante un sistema multiagente donde cada individuo de una especie es caracterizado como un círculo de cierto radio y masa que se desplaza con una rapidez constante en un universo plano finito. Las interacciones entre agentes son caracterizadas por las superposiciones de áreas de cada agente durante sus desplazamientos. Este modelo no sólo permite ajustar condiciones que muestran una evolución temporal oscilatoria acoplada de las poblaciones, propia de las distintas soluciones a la ecuación de Lotka-Volterra, sino también generar seguimiento de variables de interés ecosistémico tales como la distribución espacial de agentes o la densidad de biomasa.

Abstract In this work, the modeling of a simple ecosystem of prey and predators is presented, through a multi-agent system where each individual of a species is characterized as a circle of a certain radius and mass that moves with a constant speed in a finite plane universe. The interactions between agents are characterized by the overlapping of areas of each agent during their displacements. This model not only allows adjusting conditions that show a coupled oscillatory temporal evolution of the populations, typical of the different solutions to the Lotka-Volterra equation, but also generates monitoring of variables of ecosystem interest such as the spatial distribution of agents or the density of biomass.

Abstract The “fall armyworm”, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a significant pest of many crops, particularly maize. To control it, genetically modified plants and synthetic pesticides are the main strategies employed, which has led to the emergence of resistant populations to both methods. The earwig Doru lineare (Eschscholtz) (Dermaptera: Forficulidae) has been observed in Argentina consuming both eggs and early instars S. frugiperda larvae. To contribute to the implementation of a rational pest management system, field cage tests were conducted to assess the efficiency of D. lineare as a predator against S. frugiperda and its potential protection of maize seedlings from the pest. The results of the tests showed that the survival rate of S. frugiperda larvae was significantly affected by the presence of earwigs. When two earwigs were released into a cage containing ten maize seedlings infested with twenty S. frugiperda larvae, after ten days, the dry weight of the plants was significantly higher and the level of damage was significantly lower compared to those without earwig release. These results confirm the protective effect of D. lineare against S. frugiperda, suggesting that earwigs should be considered as promising predators in conservation control strategies for maize crops.

Resumen El “gusano cogollero”, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), es una plaga importante de muchos cultivos, particularmente del maíz. Para su control, las plantas modificadas genéticamente y los plaguicidas sintéticos son las principales estrategias empleadas, lo que ha provocado la aparición de poblaciones resistentes a ambos métodos. La tijereta Doru lineare (Eschscholtz) (Dermaptera: Forficulidae) ha sido observada en Argentina consumiendo tanto huevos como larvas de los primeros estadios de S. frugiperda. Para contribuir a la implementación de un sistema de manejo racional de plagas, se realizaron pruebas en jaulas de campo para evaluar la eficiencia de D. lineare como depredador contra S. frugiperda y su potencial protección de las plántulas de maíz de la plaga. Los resultados de las pruebas mostraron que la tasa de supervivencia de las larvas de S. frugiperda se vio significativamente afectada por la presencia de tijeretas. Cuando se liberaron dos tijeretas en una jaula que contenía diez plántulas de maíz infestadas con veinte larvas de S. frugiperda, después de diez días, el peso seco de las plantas fue significativamente mayor y el nivel de daño fue significativamente menor en comparación con aquellas sin liberación de tijeretas. Estos resultados confirman el efecto protector de D. lineare contra S. frugiperda, lo que sugiere que las tijeretas deben considerarse depredadores prometedores en las estrategias de control de conservación para cultivos de maíz.

Abstract In this study, a general model of interacting species consisting of two competing prey and a predator under the presence of pollution is formed. Criteria for the existence of equilibria and their (local and global) stability are derived. The conditions for persistence and bifurcation have also been derived. With the help of numerical simulation, it is shown how the change in the pollution level results in species extinction.

Resumen Introducción: El gusano de fuego Hermodice carunculata es un poliqueto común que puede depredar muchas especies de coral. Sin embargo, pocos estudios han examinado el efecto de la depredación del gusano de fuego en la demografía de los corales durante periodos sin brotes poblacionales. Objetivo: Este estudio tuvo como objetivo determinar si la depredación por H. carunculata compromete el crecimiento, la supervivencia y el desempeño poblacional del coral amenazado Acropora cervicornis. Métodos: Fragmentos de coral criados en vivero (n = 99) se fijaron al fondo del arrecife Punta Melones en la Isla Municipio de Culebra, Puerto Rico. La actividad de depredación y sus consecuencias demográficas en los trasplantes de coral se evaluaron desde diciembre de 2020 hasta agosto de 2022. Se comparó la susceptibilidad a la depredación entre las colonias recolectadas directamente del arrecife y las que se originaron en fuentes externas (p. ej., viveros de coral). Con los datos demográficos, se desarrollaron modelos matriciales simples de población basados en el tamaño para 1) examinar si la depredación del gusano de fuego causa una disminución significativa en la tasa de crecimiento de la población (λ), 2) determinar las transiciones demográficas que más contribuyen a λ, y 3) determinar la(s) transición(es) demográfica(s) que explican las diferencias en λ al comparar escenarios que consideraron solo colonias depredadas o la combinación de colonias depredadas y no depredadas. Resultados: La depredación aumentó con el tiempo, observándose con mayor frecuencia en la zona de mayor relieve topográfico y en colonias ajenas al sitio de estudio. Los trasplantes consumidos parcialmente crecieron significativamente más lento que las colonias no depredadas; sin embargo, la depredación no amenazó su supervivencia. La probabilidad de ser atacado por el gusano de fuego aumentó con la complejidad morfológica de la colonia. El λ estimado para un escenario que consideraba solo las colonias depredadas fue de 0.99, mientras que, para un escenario en el que se consideraron tanto las colonias depredadas como las no depredadas, λ fue de 0.91. El crecimiento de la población, en ambos escenarios, estuvo influenciado principalmente por la probabilidad de que una colonia grande sobreviviera y permaneciera en el tamaño más grande. Conclusiones: Aunque la depredación puede tener un impacto negativo en el crecimiento de los corales, una tasa de supervivencia relativamente alta de las colonias depredadas compensa los efectos adversos. Dado que la supervivencia es la transición demográfica que más contribuye al crecimiento de la población, se podría concluir que, en un escenario sin brotes, la depredación por gusanos de fuego no debe ser la causa principal de la disminución de la población de A. cervicornis.

Abstract Introduction: The fireworm Hermodice carunculata is a widespread polychaete that can prey upon many coral species. However, few studies have examined the effect of fireworm predation on coral demographics during non-outbreak periods. Objective: To determine whether predation by H. carunculata compromised the growth, survival, and population performance of the threatened coral Acropora cervicornis. Methods: Nursery-reared coral fragments (n = 99) were fixed to the bottom of Punta Melones reef in the Island Municipality of Culebra, Puerto Rico. Predation activity and its demographic consequences on coral outplants were assessed from December 2020 to August 2022. Susceptibility to predation was compared between colonies collected directly from the reef and those originating from outside sources (e.g., coral nurseries). With the demographic data, simple size-based population matrix models were developed to 1) examine whether fireworm predation led to a significant decline in population growth rate (λ), 2) determine the demographic transition(s) that contribute the most to λ, and 3) determining the demographic transition(s) that accounted for differences in λ when comparing scenarios that considered either only predated colonies or both predated and non-predated outplants. Results: Predation increased over time, being more frequently observed in the area with the highest topographic relief and on colonies foreign to the study site. Outplants that were partially consumed grew significantly slower than non-predated colonies; however, predation did not threaten their survival. The likelihood of being attacked by the fireworm increased with branching complexity. The estimated λ for a scenario considering only predated colonies was 0.99, whereas, for a scenario where both predated and non-predated colonies were considered, λ was 0.91. Population growth, under the two scenarios, was mainly influenced by the probability of a large colony surviving and remaining at the largest size. Conclusions: Although predation can negatively impact coral growth, the relatively high survival rate of predated colonies compensates for the adverse effect. Since survival is the demographic transition that contributes most to population growth, it could be concluded that under a non-outbreak scenario, fireworm predation may not be the primary cause of A. cervicornis population decline.

Resumen. En ambientes Neotropicales, sabemos poco sobre la abundancia de vertebrados silvestres tradicionalmente cazados. Con base en registros de cacería de subsistencia (2005-2019) así como en información etnográfica proveniente de campesinos-cazadores mayas, evaluamos la fluctuación interanual en la tasa de captura de venado cola blanca (Odocoileus virginianus) en una comunidad del noroeste de la Península de Yucatán. Encontramos que el número de presas disminuyó con los años, mostrando una tasa de captura (presas/salida) a la baja hasta 50% menor entre el primer (2005-2006) y tercer periodo (2010-2011) de registros. La mayoría de los entrevistados (74%; N = 31) percibieron dicha disminución del venado principalmente en los últimos 10 años y asociada a la cacería (71%). La consistencia entre la tendencia de caza y la percepción de los campesinos sobre la abundancia del venado sugiere que esta especie podría estar en riesgo ante futuros escenarios de uso en el noroeste del Mayab contemporáneo.

Abstract. In Neotropical environments, we know little about the abundance of wild vertebrates traditionally hunted. Based on subsistence hunting records (2005-2019) as well as ethnographic information from Maya peasant-hunters, we assessed the inter-annual capture rate of white-tailed deer (Odocoileus virginianus) in a rural community in the northwest of the Yucatan Peninsula. We found that the number of prey decreased over the years, showing a declining capture rate (prey/trip) that decreased by as much as 50% from the first (2005-2006) to the third period (2010-2011) of records. The majority of peasant-hunters interviewed (74%; N = 31) perceived this reduction in deer to have taken place mainly over the past 10 years as consequence of hunting (71%). The agreement between the hunting trend and peasants’ perceptions regarding the abundance of white-tailed deer suggests that this species may be at risk in future scenarios of use in northwest of contemporary Mayab.