ABSTRACT
Abstract: Florivory can alter plant reproductive success by damaging sexual reproductive structures and disrupting plant-pollinator interactions through decreased flower attractiveness. Here, we report new records of the cactus Tacinga inamoena flower consumption by the Tropidurus hispidus lizard in the Brazilian Caatinga. We monitored 53 flowers from 11 T. inamoena individuals with camera traps over a 1-year period, totalling 450 camera-days of sample effort. We detected four florivory events. In three of these events, flowers were entirely consumed or had their reproductive structures severely damaged, leading to no fruit formation. Florivory events occurred in the morning, right after anthesis, in flowers near the ground, and lizards did not climb the cactus. Our results suggest that T. hispidus florivory on T. inamoena could have a negative impact on fruit set, since the consumed flowers were entirely destroyed. However, the long-term effects of florivory by lizards on T. inamoena reproductive success in the Caatinga still needs to be elucidated.
Resumo: A florivoria pode alterar o sucesso reprodutivo da planta através de danos às estruturas reprodutivas sexuais e interrupção das interações planta-polinizador por meio da diminuição da atratividade das flores. Aqui, relatamos novos registros de consumo de flores da cactácea opuntióide Tacinga inamoena pelo lagarto Tropidurus hispidus na Caatinga brasileira. Nós monitoramos 53 flores de 11 indivíduos de T. inamoena com armadilhas fotográficas por um período de um ano, totalizando 450 dias-câmera de esforço amostral. Detectamos quatro eventos de florivoria. Em três desses eventos, as flores foram totalmente consumidas ou tiveram suas estruturas reprodutivas severamente danificadas, não levando à formação de frutos. Os eventos de florivoria ocorreram pela manhã, logo após a antese, em flores próximas ao solo, e os lagartos não escalaram o cacto. Nossos resultados sugerem que a florivoria de T. hispidus em T. inamoena pode ter um impacto negativo na frutificação, uma vez que as flores consumidas foram totalmente destruídas. No entanto, os efeitos a longo prazo da florivoria por lagartos sobre o sucesso reprodutivo de T. inamoena na Caatinga ainda precisam ser elucidados.
ABSTRACT
El estudio citogenético mediante tinción con Giemsa, en tres regiones xerofíticas (continental, peninsular e insular) del oriente de Venezuela, demostró un número diploide 2n=36, compuesto por seis pares de macrocromosomas metacéntricos y submetacéntricos y 12 pares de microcromosomas acrocéntricos manteniéndose esta característica en machos y hembras en las tres poblaciones estudiadas. Se determinó que el primer par de macrocromosomas es metacéntrico y en la región continental representa 13% de longitud relativa total (LRT), siendo el cromosoma de mayor tamaño con respecto a la población peninsular con un 9,4 % y a la población insular con 7,1 %, conteniendo esta última población los cromosomas más pequeños. Considerando las diferencias cromosómicas y el aislamiento geográfico existente, estos lagartos podrían presentar un proceso de especiación alopátrica de tipo vicariante.
A cytogenetic study by Giemsa staining in three xerophytic regions (continental, peninsular and insular) in eastern Venezuela, showed a diploid number 2n=36, consisting of 6 pairs of metacentric and submetacentric macrochromosomes and 12 pairs of acrocentric microchromosomes maintained, this feature in males and females in the three populations studied. It was determined that the first pair of macrochromosomes is metacentric and the continental region represents 13% of total relative length (LRT) as the larger chromosome, with respect to the peninsular population with 9.4% and the insular population 7.1%, the latter population containing the smallest chromosomes. Whereas chromosomal differences and geographic isolation exists, these lizards have a process of vicariant allopatric speciation.
ABSTRACT
Se estudiaron aspectos de ecología térmica y patrón de actividad del lagarto Tropidurus hispidus en un bosque tropófilo del estado Sucre, Venezuela entre junio de 2007 y mayo de 2008. La temperatura media corporal fue de 35,68±1,4 ºC y con un intervalo entre 32,6 y 37,80 ºC. En hembras el intervalo de temperatura corporal (Tc) en sequía fue 34-38 ºC y en lluvia fluctuó entre 32-38 ºC. En machos el intervalo de temperatura corporal (Tc) en sequía fue 35-37ºC y en lluvia 34-35 ºC. Mediante una regresión lineal, no se encontró relación entre la temperatura del aire (Ta) y sustrato (Ts). La tendencia ter-morreguladora indica que la especie es termorreguladora activa durante el período de sequía y lluvia. Dividiendo la actividad horaria en tres segmentos: matutino, medio día y vespertino, el patrón de actividad fue bimodal en sequía y unimodal en lluvia. Para relacionar el patrón de actividad con las variables ambientales (aire y sustrato) se utilizó la correlación de Pearson, en sequia se obtuvo una correlación negativa con la tempera-tura del aire (-0,78) y con el sustrato (-0,65). En lluvia no se relacionó con la tempera-tura del aire (-0,056) ni con el sustrato (-0,040). La amplitud del nicho térmico se calculó empleando el índice de Levins, no observándose diferencias apreciables entre machos y hembras en ambos períodos y la sobreposición de nicho térmico entre sexos, obtenido mediante el índice de Pianka, fue 0,81 en lluvia y 0,90 en sequía.
We studied aspects of thermal ecology and activity patterns in the lizard Tropidurus hispidus in a forest tropophic of Sucre State, Venezuela between June 2007 and May 2008. The body temperature was 35.68±1.4 °C from 32.6 to 37.80 °C. Females body temperature (Tb) in drought and rainfall was 34-38 ºC and 32-38 ºC, respectively. In males the range of body temperature (Tb) in drought was 35-37 °C and 34-35 °C. in rain. No relation was found between the air temperature (Ta) and substrate temperature (Ts). Thermoregulatory trend, indicate active thermoregulation in drought and rain. Dividing the activity into three time segments: morning, afternoon and evening and the pattern of activity was bimodal in drought and unimodal in rain. To relate the pattern of activity with environmental variables (air and substrate) using the Pearson correlation in drought was a negative correlation with air temperature (-0.780) and with the substrate (-0.65). Rain was not associated with the air temperature (-0.056) or the substrate (-0.040). The thermal niche breadth was calculated using the Levins index, we did not find significant differences between males and females in both periods and thermal niche overlap between sexes, obtained by the Pianka index was 0.81 in rain and 0.90 in drought.