Reproductive ecology of the glass frog Espadarana prosoblepon (Anura: Centrolenidae) in an urban forest of the Central Andes of Colombia

Population and reproductive behaviour aspects of the glass frog Espadarana prosoblepon are well known for populations from Central America, but similar information is lacking for populations from South America. We recorded the reproductive ecology of a population of the glass frog E. prosoblepon in the city of Armenia, Central Andes of Colombia. With weekly surveys with mark-recapture between December 2013 and November 2015, we monitored activity patterns and evaluated if the probability of males mating is associated to their body size or to chorus tenure (i.e. the number of nights a same individual is calling for attracting a mate). In addition, upon observing an amplexus, we recorded the behaviour of the individuals until oviposition and noted characteristics of egg clutch. We recorded 47 males and 32 females, nine amplexus events, eight ovipositions, and 21 egg clutches (35.4 ± 4.79 eggs per clutch, N = 29). Activity of males and females and the number of egg clutches were positively correlated to rainfall. Mating success of males was not associated to their body size, but it was positively associated to longer chorus tenure; clutches from large females had a higher number of eggs than clutches from small females. Oviposition occurred on average 3.76 ± 1.74 hours after we first observed the amplexus, occurring 93.1% of the time in fronds of Selaginella geniculata at an average height of 1.58 ± 0.44 m. After the oviposition, the male left the site, while the female remained between 30 and 45 min, partially covering the eggs. The reproductive behaviour of E. prosoblepon did not vary widely between a population in Costa Rica and our population in time to oviposition, and mating success of males associated to chorus tenure; however, in our study population we recorded a larger clutch size and the preference for S. geniculata fronds as oviposition substrate.     

Elucidating the diel and seasonal calling behaviour of Elachistocleis matogrosso (Anura: Microhylidae)

ABSTRACT

Acoustic monitoring provides the opportunity to study ecological processes that are difficult to assess with traditional surveys. Elachistocleis matogrosso is an anuran species, described in 2010, for which limited biological information is available. This study investigated the calling activity of the species in the north-eastern portion of the Pantanal, Brazil, a wetland area with marked seasonality between the dry and wet seasons. The calling activity of E. matogrosso was monitored using automated digital recorders in combination with automated signal recognition software over two different annual cycles. The species was vocally active only during the wet season (October – April), with a peak in November-December during the 2013–2014 annual cycle and in February-March during the 2015–2016 annual cycle. The peak calling activity occurred at dusk. This species has nocturnal habits and an explosive breeding activity. The detection of the species was intermittent, which suggests that environmental predictors or site-specific conditions might play an important role in species detection. Moreover, this intermittent occupancy indicated that surveys that employ traditional field techniques would likely fail to detect this species. We describe an effective protocol for detecting E. matogrosso with acoustic monitoring, which requires recording during 20 days in February from 17:01 to 05:00. Our procedure would be easy to adapt to other anuran species, and it could be used for investigating new localities and assessing population changes over time.     

Is it all death feigning? Case in anurans

Anurans are known to feign death as a way to avoid or minimize the risk of predation. However, information on this defensive strategy is scattered and we believe that there is more than one behaviour type referred to as thanatosis. Here we review the literature, add original data, and propose definitions and new names that complement the present knowledge on the subject. We collected information on 334 individuals of 99 species in 16 families and grouped the recorded displays into two categories of tonic immobility: (1) thanatosis, death-feigning, or playing possum, and (2) shrinking or contracting. These two categories are treated as different behaviour types because of the display pattern (position of fore- and hindlimbs, eye opening), presence of skin toxins (shrinking is mostly displayed by toxic species, whereas thanatosis is mostly displayed by non-toxic species), social context (interaction with predators), and their putative or actual functions.     

Fluctuating asymmetry in populations of the South American frog Physalaemus cuvieri (Leptodactylidae) in areas with different degrees of disturbance

Methods to measure and monitor wild populations are important conservation tools in areas affected by anthropogenic disturbances. We compared three populations of the South American frog Physalaemus cuvieri Fitzinger, 1826 (Leptodactylidae) from areas with different degrees of anthropogenic disturbance in regard to their degrees of fluctuating asymmetry (FA). We selected four morphological characters (radio-ulna, femur, tibia-fibula and digit length) and compared two populations from relatively pristine areas with one population located in a highly urbanised and disturbed area. We found a significantly higher level of FA for the digit length, p < 0.05, in the population suffering the highest level of anthropogenic disturbance in relation to the two populations located in the pristine areas. There are no significant differences in the three populations in regard to FA for the radio-ulna, femur and tibia-fibula. The absence of FA in these three measurements might indicate a negative effect of limb asymmetry on this species survivorship. Our study provides a good example of the use of FA as indicator of environmental stress. However, this result must be viewed with some caution, since we observed FA in only one morphological character.     

Anurans of a seasonally dry tropical forest: Morro do Diabo State Park,São Paulo state,Brazil

We studied the richness and composition of the anuran assemblage of Morro do Diabo State Park, the major remnant of Mesophytic Semideciduous Forest in the state of São Paulo, Brazil, through hypothesis tests. From September 2005 to March 2007 we recorded 28 anuran species, comprising a mix of Atlantic, Cerrado and South American widespread species, usually considered tolerant to anthropic modifications. The low richness of species and reproductive modes, the predominance of habitat generalist species, and the high similarity with Cerrado areas can be explained by the climatic seasonality of the studied area (a pronounced dry season), as well as its large distance from centres of anuran diversification, such as the coastal mountains of the wet Atlantic Forest.