Vertebrate florivory of vascular epiphytes: the case of a bromeliad / Florivores vertebrados de epífitas vasculares: o caso de uma bromélia

Abstract The avoidance of vertebrate herbivory is thought to be one of the possible drivers for the evolution of epiphytism. Scarce literature suggests that epiphyte herbivory is mainly related to insect attack on reproductive structures. In a pine-oak forest we observed almost all inflorescences of an epiphytic bromeliad (Tillandsia carlos-hankii) with signs of florivory; the degree of damage suggested that vertebrate herbivores could be involved. To assess the intensity of vertebrate florivory damage we recorded the percentage of damaged individuals in a 500 m2 plots during two flowering seasons. To identify possible vertebrate herbivores, we installed 20 mixed capture stations, 10 photo-traps focused on bromeliads and analyzed stomach contents of captured vertebrates. Florivory was observed on 62% of individuals during the first flowering season and 77% on the second; and average one individual lost 41% of reproductive structures. Vertebrates associated with florivory were a bird, Icterus bullockii (Aves, Passeriformes, Icteridae), a squirrel Sciurus aureogaster (Mammalia, Rodentia, Sciuridae), and mice, Peromyscus gratus, P. levipes and P. aztecus (Mammalia, Rodentia, Cricetidae). Our results suggest that vascular epiphytes are used as opportunistic resources for small vertebrates during seasons when preferred resources are scarce.

Resumo Acredita-se que a prevenção da herbivoria dos vertebrados é um dos possíveis impulsores da evolução da epífita. A literatura escassa sugere que a herbivora em epífitas está relacionada principalmente ao ataque de insetos as estruturas reprodutivas. Em uma floresta de pinheiros observamos que quase da todas as inflorescências de uma bromélia epífita (Tillandsia carlos-hankii) apresentavam sinais de florivoria; o grau de danos sugeria que herbívoros majores (vertebrados) pudessem estar envolvidos. Para avaliar a intensidade do dano de florivoria de vertebrados, registramos a porcentagem de indivíduos danificados em quadrantes de 500 m2 durante duas estações de florescimento. Para identificar possíveis herbívoros vertebrados, instalamos 20 estações de captura mista e analisamos o conteúdo estomacal de vertebrados capturados. Além disso, foram instaladas 10 foto-armadilhas focadas em bromélias. A florivoria foi observada em 62% dos indivíduos durante a primeira estação de floração e 77% na segunda. Os vertebrados associados à florivoria foram pássaro, Icterus bullockii (Aves, Passeriformes, Icteridae), um esquilo Sciurus aureogaster (Mammalia, Rodentia, Sciuridae) e ratos, Peromyscus gratus, P. levipes e P. aztecus (Mammalia, Rodentia, Cricetidae). Assim, nossos resultados sugerem que epífitas vasculares são usadas como recurso facultativo para estes animais durante as estações, quando os recursos preferidos estão escassos.

Vertebrate florivory of vascular epiphytes: the case of a bromeliad

Abstract The avoidance of vertebrate herbivory is thought to be one of the possible drivers for the evolution of epiphytism. Scarce literature suggests that epiphyte herbivory is mainly related to insect attack on reproductive structures. In a pine-oak forest we observed almost all inflorescences of an epiphytic bromeliad (Tillandsia carlos-hankii) with signs of florivory; the degree of damage suggested that vertebrate herbivores could be involved. To assess the intensity of vertebrate florivory damage we recorded the percentage of damaged individuals in a 500 m2 plots during two flowering seasons. To identify possible vertebrate herbivores, we installed 20 mixed capture stations, 10 photo-traps focused on bromeliads and analyzed stomach contents of captured vertebrates. Florivory was observed on 62% of individuals during the first flowering season and 77% on the second; and average one individual lost 41% of reproductive structures. Vertebrates associated with florivory were a bird, Icterus bullockii (Aves, Passeriformes, Icteridae), a squirrel Sciurus aureogaster (Mammalia, Rodentia, Sciuridae), and mice, Peromyscus gratus, P. levipes and P. aztecus (Mammalia, Rodentia, Cricetidae). Our results suggest that vascular epiphytes are used as opportunistic resources for small vertebrates during seasons when preferred resources are scarce.

Resumo Acredita-se que a prevenção da herbivoria dos vertebrados é um dos possíveis impulsores da evolução da epífita. A literatura escassa sugere que a herbivora em epífitas está relacionada principalmente ao ataque de insetos as estruturas reprodutivas. Em uma floresta de pinheiros observamos que quase da todas as inflorescências de uma bromélia epífita (Tillandsia carlos-hankii) apresentavam sinais de florivoria; o grau de danos sugeria que herbívoros majores (vertebrados) pudessem estar envolvidos. Para avaliar a intensidade do dano de florivoria de vertebrados, registramos a porcentagem de indivíduos danificados em quadrantes de 500 m2 durante duas estações de florescimento. Para identificar possíveis herbívoros vertebrados, instalamos 20 estações de captura mista e analisamos o conteúdo estomacal de vertebrados capturados. Além disso, foram instaladas 10 foto-armadilhas focadas em bromélias. A florivoria foi observada em 62% dos indivíduos durante a primeira estação de floração e 77% na segunda. Os vertebrados associados à florivoria foram pássaro, Icterus bullockii (Aves, Passeriformes, Icteridae), um esquilo Sciurus aureogaster (Mammalia, Rodentia, Sciuridae) e ratos, Peromyscus gratus, P. levipes e P. aztecus (Mammalia, Rodentia, Cricetidae). Assim, nossos resultados sugerem que epífitas vasculares são usadas como recurso facultativo para estes animais durante as estações, quando os recursos preferidos estão escassos.

Nitric oxide production by Peromyscus yucatanicus (Rodentia) infected with Leishmania (Leishmania) mexicana

Peromyscus yucatanicus (Rodentia: Cricetidae) is a primary reservoir of Leishmania (Leishmania) mexicana (Kinetoplastida: Trypanosomatidae). Nitric oxide (NO) generally plays a crucial role in the containment and elimination of Leishmania. The aim of this study was to determine the amount of NO produced by P. yucatanicus infected with L. (L.) mexicana. Subclinical and clinical infections were established in P. yucatanicus through inoculation with 1 x 10 2 and 2.5 x 10 6 promastigotes, respectively. Peritoneal macrophages were cultured alone or co-cultured with lymphocytes with or without soluble Leishmania antigen. The level of NO production was determined using the Griess reaction. The amount of NO produced was significantly higher (p ≤ 0.0001) in co-cultured macrophages and lymphocytes than in macrophages cultured alone. No differences in NO production were found between P. yucatanicus with subclinical L. (L.) mexicana infections and animals with clinical infections. These results support the hypothesis that the immunological mechanisms of NO production in P. yucatanicus are similar to those described in mouse models of leishmaniasis and, despite NO production, P. yucatanicus is unable to clear the parasite infection.

Preliminary study towards a novel experimental model to study localized cutaneous leishmaniasis caused bY Leishmania (Leishmania) mexicana / Estudio preliminar sobre un nuevo y original modelo experimental de leishmaniosis cutánea localizada causada por Leishmania (Leishmania) mexicana

There is not an experimental model of localized cutaneous leishmaniasis (LCL) caused by Leishmania (Leishmania) mexicana. The aim of the present study was to characterize the clinical and histological features of Peromyscus yucatanicus experimentally infected with L. (L.) mexicana. A total of 54 P. yucatanicus (groups of 18) were inoculated with 1x10(6) promastigotes of L. (L.) mexicana in the base of the tail. They were euthanized at three and six months post experimental infection. The control group was inoculated with RPMI-1640. The predominant clinical sign observed was a single ulcerated lesion in 27.77% (5/18) and in 11.11% (2/18) P. yucatanicus at three and six months respectively. The histological pattern described as chronic granulomatous inflammation with or without necrosis was found in 7/7 (100%) biopsies of euthanized P. yucatanicus at three (n = 5) and six (n = 2) months, respectively. These results resembled clinical and histological features caused by L. (L.) mexicana in humans, and support the possibility to employ P. yucatanicus as a novel experimental model to study LCL caused by this parasite.

No existe un modelo experimental de la leishmaniosis cutánea localizada (LCL) causada por Leishmania (Leishmania) mexicana. El objetivo del presente estudio fue el de caracterizar los cuadros clínico e histológico de Peromyscus yucatanicus infectados experimentalmente con L. (L.) mexicana. Un total de 54 P. yucatanicus (grupos de 18) fueron inoculados en la base de la cola con 1x10(6) promastigotes de L. (L.) mexicana. A los 3 y 6 meses posteriores a la infección experimental fueron sacrificados. El grupo control fue inoculado con RPMI-1640. El signo clínico predominante fue una lesión única ulcerada en 27.77% (5/18) y en 11.11% (2/18) P. yucatanicus a los 3 y 6 meses respectivamente. El patrón histológico descrito como inflamación crónica granulomatosa con o sin necrosis se observó en 7/7 (100%) biopsias de los P. yucatanicus a los 3 (n=5) y 6 (n=2) meses respectivamente. Los resultados son similares a los cuadros clínico e histológico de la infección por L. (L.) mexicana en humanos, y apoyan la posibilidad de utilizar P. yucatanicus como un nuevo y original modelo para el estudio de la LCL causada por L. (L.) mexicana.

Los hantavirus causantes de la fiebre hemorrágica con síndrome renal y del síndrome pulmonar / The hantaviruses causing hemorrhagic fever with renal syndrome and pulmonary syndrome

Este trabajo de revisión se enfoca en el análisis de la información básica sobre los hantavirus, agentes causales de dos enfermedades importantes en salud pública: la fiebre hemorrágica con síndrome renal (FHSR) y el síndrome pulmonar por hantavirus (SPH), dos zoonosis distribuidas en Asia/Europa y el continente americano, respectivamente. Los hantavirus se transmiten al hombre a través de la manipulación y contacto directos de roedores infectados o tejidos y secreciones (orina, heces y saliva). La FHSR y el SPH comparten algunas características clínicas, aunque las hemorragias y la afectación renal son propias de la FHSR,y los problemas respiratorios del SPH. Se aportan algunos datos sobre estudios realizados en México sobre hantavirus y se mencionan las condiciones ecológicas vinculadas con la distribución de los virus y sus reservorios naturales, así como algunas medidas para evitar o reducir el riesgo de infección.

The goal of this review is to provide basic information on hantaviruses as causative agents of Hemorrhagic Fever with Renal Syndrome (HFRS) and Hantavirus Pulmonary Syndrome (HPS), two zoonotic diseases widely distributed in Asia/Europe, and the American continent, respectively. Hantaviruses are rodent-borne and transmitted to humans by direct contact with infected rodents or their secretions (urine, feces and saliva). Both, HFRS and HPS share some clinical aspects, however, hemorrhage and renal failure are the hallmark of HFRS, while respiratory problems are distinctive signs and symptoms of patients with HPS. Studies on hantavirus infection in rodents from Mexico are included, some recomendations to prevent or avoid contact with rodents are mentioned, and some determinant ecologic factors of hantaviruses distribution and their natural rodents, are also included.

Ecología poblacional del ratón Peromyscus mexicanus (Rodentia: Muridae) en el Parque Nacional Volcán Poás, Costa Rica

Population ecology of the mouse Peromyscus mexicanus (Rodentia: Muridae) in Poas Volcano National Park, Costa Rica. The Mexican Deer Mouse has been reported as an abundant wild mouse in Costa Rica; nevertheless, it has not been studied as well as other Peromyscus species. Thirty Sherman traps were placed on three habitats during six consecutive days of each month, from March 2002 through April 2003 in three sites of Poás volcano National Park, Costa Rica. A total of 2 393 mice were captured. Other species such as Reithrodontomys creper, R. rodriguezi, Scotinomys teguina and Oryzomys devius (Muridae) were also captured in Tierra Fría and R. creper, R. sumichrasti, S. teguina and O. devius in Potrero Grande. in Canto de las Aves we captured P. mexicanus, R. creper, R. rodriguezi and O. devius. Of the total mice collected, 34.77 % were P. mexicanus. For this species, the mean monthly capture per hectare was 34±2.15 in Tierra Fría and 11±1.85 in Potrero Grande. in the third site, Canto de las Aves, only four mice were captured throughout the study. The estimated population size did not change among months in Tierra Fría, but it did in Potrero Grande. No sex ratio variation was found in any habitat. In Potrero Grande, weight averages were 43.54±3.42 g for males and 42.08±3.4 5 g for females. variation in population structure among habitats was not significant. The presence of oak trees (Quercus sp.) and the high understory density could explain the stability of the population in this area. Rev. Biol. Trop. 55 (3-4): 1037-1050. Epub 2007 December, 28.

Se estudió el tamaño poblacional, la proporción de sexos, el peso y el número de adultos e inmaduros de Peromyscus mexicanus en tres sitios, durante 14 meses, en el Parque Nacional volcán Poás, Costa Rica. Se colocaron 30 trampas Sherman en cada sitio, para un estudio de captura-recaptura durante seis días consecutivos de cada mes, desde marzo de 2002 hasta abril de 2003. Se hicieron 2 393 capturas, hallándose en Tierra Fría, además de P. mexicanus, Reithrodontomys creper, R. rodriguezi, Scotinomys teguina y Oryzomys devius (Muridae). En Potrero Grande se capturaron P. mexicanus, R. creper, R. sumichrasti, S. teguina y O. devius. En Canto de las Aves se capturaron P. mexicanus, R. creper, R. rodriguezi y O. devius. El 34.77 % del total de ratones capturados fueron P. mexicanus. Se capturaron en promedio 34 individuos por mes por hectárea en Tierra Fría y 11 en Potrero Grande; en Canto de las Aves sólo se capturaron 4 individuos en todo el muestreo. El tamaño estimado de la población de P. mexicanus no varió mensualmente en Tierra Fría, pero si en Potrero Grande. No se observó variación en la proporción de sexos en ninguno de los dos sitios. El valor promedio de peso en Tierra Fría fue de 43.83+1.93 g machos 39.29+2.07 g hembras. En Potrero Grande fue 43.54+3.42 g machos y 42.08+3.45 g hembras. En ninguno de los dos sitios se encontraron diferencias en la cantidad de individuos inmaduros a través del tiempo.