Demography and Behaviour of Teinopodagrion oscillans (Odonata: Megapodagrionidae) in a Protected Area of the Colombian Andean Region.

The demography and behaviour of Teinopodagrion oscillans was studied in a protected area in the Andean region of Colombia. Adult damselflies were individually marked, and using their recapture histories, we estimated survival, longevity, sex ratio, and population size using Cormack-Jolly-Seber models. Other aspects of their behaviour were recorded. Survival, recapture, and lifespan (14.1 ± 0.59 days) were similar for both sexes and all age groups. Mature males were larger, and the distance from the water was similar for all individuals. The most supported model was the time-dependent model for survival and recapture. This suggests that weather variations affect the demography of this population in a significant way. Individuals exhibited high fidelity to their site perch, perching with open wings near water on a variety of perches. Mature males make short flights from the perch to intercept conspecific and interspecific males and to hunt prey. The tandem position was formed on macrophytes, and then the pair flew away. Oviposition lasted for 11.23 min on average, with the females ovipositing by abdomen submersion. Our results offer insights into the demographic characteristics and behaviour of this species, providing crucial information for the short- and long-term, from the demography of one species to the conservation of ecosystems of the Andean region.

High Foraging Fidelity and Plant-Pollinator Network Dominance of Non-native Honeybees (Apis mellifera) in the Ecuadorian Andes.

Pollinator foraging fidelity (i.e., consistent and repeated visitation to a particular plant species or area) is poorly understood for most bee species, but is important information for both the conservation of plant and pollinator species and the ecosystem services they provide to humans. We used plant-pollinator surveys and mark-recapture of floral-visiting Hymenoptera to study the foraging fidelity and species interaction network properties of a plant-pollinator community in the tropical Andes of southern Ecuador. After marking 92 bees visiting six plant taxa along four 100-m transects between July 16th and July 31st of 2019, only honeybees were resighted at a recapture rate of 47.7% (41/86). During our surveys, we observed nine bee and two wasp taxa feeding from the flowers of 10 morphospecies of plants, and we found significantly low network nestedness and significantly high network-level specialization. Specialization (d') was also significant for honeybees and bumblebees and for three plant taxa. Overall, our findings indicated that feral, non-native honeybees in this region dominated the local plant-pollinator network, yet this species is acting as a specialist forager at the individual level. Our results suggest that honeybees may be replacing the pollination services of some native bees and wasps in the region, but more research is needed to determine the effectiveness of honeybee pollination for the local plants.

Spatiotemporal variation in the adult sex ratio, male aggregation, and movement of two tropical cloud forest dung beetles.

While theory suggests that at conception the sex ratio should be balanced (1:1), this can be variable across space and time in wild populations. Currently, studies of the environmental factors that regulate adult sex ratio (ASR) in species with different life history traits are scarce. Using capture-recapture over a year, we analyzed the influence of habitat type (forest and nonforest) and season (rainy and dry) on variation in ASR, male aggregation and the trajectory movement of 2 dung beetle species with different life history traits: Deltochilum mexicanum (a hornless roller species) and Dichotomius satanas (a tunneler species with horns on its head and thorax). We found opposite tendencies. The D. mexicanum population tends to be female-biased, but the population of D. satanas tends to be predominantly male, and observed values were not related to habitat type or season. However, the 95% confidence intervals estimated were highly variable between seasons depending on habitat. On examining the monthly variation in ASR for both habitats, we found that it depends on the species. In addition, male aggregation differed between species depending on habitat type and season, and species movement patterns were closely related to their habitat preferences. Based on our results, we argue that comparative population studies of species with different life history traits are necessary to understand the variation in demographic parameters as well as its ecological and evolutionary implications in the face of spatial and climatic environmental variation.

Habitat preference, movements and growth of giant mottled eels, Anguilla marmorata, in a small subtropical Amami-Oshima Island river.

Although anguillid eel populations have decreased remarkably in recent decades, few detailed ecological studies have been conducted on tropical eels such as the giant mottled eel whose range extends across the whole Indo-Pacific. This species was studied throughout the entire 0.5 km mainstem reaches of Oganeku River on the subtropical Amami-Oshima Island of Japan over a two-year period using four sampling periods to understand its habitat preference, early life-stage dispersal process, movements, and annual growth using a mark-recapture experiment conducted with quantitative electrofishing. A total of 396 juvenile growth-phase A. marmorata eels were caught and tagged, with 48 individuals being recaptured at least once. Their density irrespective of size of eels was most strongly determined by distance from the river mouth, followed by riverbank type according to random forest models. Eel density decreased with increasing distance from the freshwater tidal limit located about 100-150 m from the river mouth. Eels preferred vegetated riverbanks, while they avoided those of concrete and sand. The density of small eels (total length: TL < 240 mm) was also associated with depth and velocity, with small eels tending to prefer riffle or run habitats. In contrast, large eels (TL ≥ 240 mm) were found in habitats of any depth and velocity. The TL of eels had a minimum peak at around the tidal limit, and it increased with increasing distance from the tidal limit. The observed density and size gradients of eels in relation to the distance from the river mouth suggested that A. marmorata initially recruited to freshwater tidal limit areas and then dispersed in both downstream and upstream directions. The growth rate of eels varied greatly among individuals that were at large for various periods of time and ranged from 0 to 163.2 mm/year (mean ± SD of 31.8 ± 31.0 mm/year). Of the recaptured eels, 52.1% were recaptured in a section that was different from the original capture section, and their mean ± SD distance travelled was 46.5 ± 72.5 m (median = 20 m). 47.9% of the eels were recaptured from the original section of capture (i.e., <10 m distances travelled), suggesting that they had strong fidelity to specific habitats with limited movements. The distance travelled of eels that had moved was greater for small eels (range = 10-380 m; mean ± SD = 84.4 ± 121.9 m) than large individuals (range = 10-120 m; mean ± SD = 30.9 ± 31.0 m), which indicates that the mobility of the eels declines as they grow. This is the first clear detailed documentation of the spatial distribution, growth, and movements of tropical eels in a small river system in relation to environmental conditions that provides an example of how future studies can be conducted in other areas to understand how conservation efforts can be most efficiently targeted for maximum success.

Oversummering juvenile and adult Semipalmated sandpipers in Perú gain enough survival to compensate for foregone breeding opportunity.

BACKGROUND: Age at maturity and the timing of first breeding are important life history traits. Most small shorebird species mature and breed as 'yearlings', but have lower reproductive success than adults. In some species, yearlings may defer northward migration and remain in non-breeding regions ('oversummering') until they reach 2 years of age. Some adults also oversummer. Oversummering would be favoured by natural selection if survival were as a result raised sufficiently to compensate for the missed breeding opportunity. Several thousand Semipalmated Sandpipers (Calidris pusilla) spend the non-breeding period at Paracas, Perú, including individuals with long bills (likely from eastern Arctic breeding populations ~ 8000 km distant) and short bills (likely from western Arctic breeding populations, up to 11,000 km distant), with short-billed birds more likely to oversummer. We tested the prediction that oversummering birds have higher survival than migrants, and that the magnitude of this higher survival for oversummering birds is enough to compensate for their lost breeding season. METHODS: We used a Multi-State Mark-Recapture model based on 5 years of encounter data (n = 1963 marked birds, and 3229 resightings) obtained year-round at Paracas, Perú, to estimate seasonal (i.e. breeding and non-breeding) survivorship for migrant and oversummering birds. We calculated the magnitude of the oversummering survival advantage required to compensate, for both yearlings and adults, based on published measures of annual survival and reproductive success. Using bill length as a proxy for migration distance, we investigated whether migratory survival is distance-dependent. RESULTS: We estimate that 28% of yearlings and 19% of adults oversummer. Survival is higher for oversummering birds than for migrants, and the oversummering survival advantage is greater for adults (0.215) than for yearlings (0.140). The theoretical thresholds predicted by the size of the missed reproductive opportunity are 0.240 for adults and 0.134 for yearlings. Migratory survival decreases and the oversummering rate increases with migration distance, as assessed by culmen length. CONCLUSIONS: Our results support the life history hypothesis that oversummering raises survival enough to compensate for the loss of a breeding opportunity. Greater migration distance lowers survival and increases the probability of oversummering.

The abundance of false killer whale, Pseudorca crassidens (Cetartiodactyla: Delphinidae) in coastal waters of Golfo Dulce and Osa Peninsula, Costa Rica / Abundancia de la falsa orca, Pseudorca crassidens (Cetartiodactyla: Delphinidae) en las aguas costeras del Golfo Dulce y la Península de Osa, Costa Rica

Introduction: False killer whale (Pseudorca crassidens) is a tropical and subtropical social species that live in groups with individuals of mixed ages and sex classes. False killer whales have been documented since the late 1990s in Southwestern Costa Rica. Objective: To estimate the abundance of false killer whales in Osa Peninsula waters. Methods: Cetacean surveys off the Osa Peninsula Waters (OPW), Costa Rica, yielded opportunistic encounters with false killer whales in Drake Bay and Caño Island (2001-2019) and observations during formal surveys in Golfo Dulce (2005-2015). Photo-identification data was analyzed using capture-mark-recapture models in the study area, through an open population (POPAN) framework, considering the effect of time on the parameters apparent survival and capture probability, producing an abundance estimate for a superpopulation in the entire study area. Results: False killer whale abundance in OPW is characterized by a small population size of no more than 100 individuals, complemented by a very low probability of encounter and a contrasting high apparent survival. Conclusions: This population estimate should be taken as conservative, however, the small population size of less than 100 individuals should be considered vulnerable, in contrast to the increasing anthropogenic impacts in the coastal seascape. We argue the potential occurrence of population units along the coastal seascape of the Pacific littoral and oceanic island-associated units at Isla del Coco.

Introducción: La falsa orca es una especie gregaria tropical y subtropical, que vive en grupos con individuos de diferentes clases de edad y sexo. La falsa orca ha sido documentada en el sur-oeste de Costa Rica desde finales de los 90s. Objetivo: Evaluar el uso de hábitat de la especie en términos de abundancia. Métodos: Observaciones en campo para cetáceos en aguas de la Península de Osa (APO), incluyen encuentros oportunísimos en Bahía de Drake y la Isla del Caño (2001-2019), así como observaciones directas de Pseudorca crassidens, durante muestreos formales en Golfo Dulce (2005-2015). Se analizaron datos sobre foto-identificación utilizando modelos de marcaje captura y recaptura, considerando un enfoque para población abierta (POPAN), el cual considera el efecto del tiempo en los parámetros demográficos: supervivencia aparente (ф) y probabilidad de captura (P), produciendo un estimado de abundancia que comprende toda la superpoblación en el área de estudio. Resultados: La abundancia de la falsa orca en APO se caracteriza por un tamaño poblacional pequeño, de menos de 100 individuos, que se complementa por una muy baja probabilidad de captura, en contraste con una supervivencia aparente alta. Conclusión: Este estimado debe tratarse como conservativo, no obstante, el pequeño número poblacional, de menos de 100 individuos debe considerarse como vulnerable, en contraste con el incremento del impacto antropogénico del paisaje marino costero. Se discute la posible presencia de unidades poblacionales en el paisaje costero del litoral Pacífico y de unidades oceánicas asociadas a la Isla del Coco.

Full-annual demography and seasonal cycles in a resident vertebrate.

Wildlife demography is typically studied at a single point in time within a year when species, often during the reproductive season, are more active and therefore easier to find. However, this provides only a low-resolution glimpse into demographic temporal patterns over time and may hamper a more complete understanding of the population dynamics of a species over the full annual cycle. The full annual cycle is often influenced by environmental seasonality, which induces a cyclic behavior in many species. However, cycles have rarely been explicitly included in models for demographic parameters, and most information on full annual cycle demography is restricted to migratory species. Here we used a high-resolution capture-recapture study of a resident tropical lizard to assess the full intra-annual demography and within-year periodicity in survival, temporary emigration and recapture probabilities. We found important variation over the annual cycle and up to 92% of the total monthly variation explained by cycles. Fine-scale demographic studies and assessments on the importance of cycles within parameters may be a powerful way to achieve a better understanding of population persistence over time.

Linking local movement and molecular analysis to explore philopatry and population connectivity of the southern stingray Hypanus americanus.

Limited data pertaining to life history and population connectivity of the data-deficient southern stingray (Hypanus americanus) are available. To determine potential vulnerabilities of their populations, this study aimed to analyse their movement patterns and genetic variability. A population of southern stingrays encompassing nine sites around Cape Eleuthera, the Bahamas, has been monitored using mark-recapture, spanning a 2.5 year period. Out of 200 individual stingrays, more than a third were encountered again. The home range of the females appears to be restricted, which supports the notion of high site residency. As resident populations of stingrays could suffer from a lack of population connectivity and be predestined for genetic isolation and local extirpation, this study further investigated the genetic connectivity of four sample sites in the central and western Bahamas. A haplotype analysis from the mitochondrial D-loop region showed that no distinct population structure strictly correlated with the sample site. These findings were complemented by five microsatellite loci that revealed high degrees in genotypic variability and little population differentiation. The results suggest gene flow mediated by both males and females.

Individual asymmetry as a predictor of fitness in the bat Carollia perspicillata.

The measurement of fitness in wild populations is a challenging task, and a number of proxies have been proposed with different degrees of success. Developmental instability/stability (DI) is an organismal property associated with variance in bilateral asymmetry (fluctuating asymmetry-FA) and a correlated effect on fitness. This study provides evidence to corroborate the hypothesis that asymmetry partly reflects DI and is correlated with a reduction in fitness measured by survival and reproduction in bats. We studied two colonies of the bat Carollia perspicillata in southeastern Brazil over 5 years, marking and recapturing individuals. Gaussian mixture models for signed Forearm Asymmetry (ForA) distribution indicated that ~20% of asymmetry variation was due to DI heterogeneity among individuals. ForA, body condition (Scaled Mass Index-SMI) and Forearm Length (ForL) were used as predictors of survival probability in Cormack-Jolly-Seber models. Asymmetry was negatively associated with survival, whereas SMI and ForL were positively associated. The male C. perspicillata defend sites within the roost that are favoured by female harems, but there are mating opportunities for bachelor males, leading to both territorial disputes and sperm competition. As predicted by sexual selection, ForA was negatively associated with relative Testicle Length, a measure of reproductive potential. In females, ForA was negatively associated with the probability of two pregnancies (as opposed to one) in a given breeding season. The effect magnitudes and directions of associations suggest that asymmetry, even though not perfectly reflecting DI variation, is a useful predictor for fitness components in C. perspicillata.

More than 5 Years! An Unusually Long-Lived Dung Beetle (Scarabaeinae) in an Andean Agricultural Landscape.

Despite their importance as ecological indicators of anthropic perturbation, most of our knowledge about Neotropical dung beetles (Coleoptera: Scarabaeinae) is derived from studies conducted at the community level. To date, at a global scale, there is still incipient knowledge about the population ecology of the Scarabeinae species. The study of these insects at the population level offers new data pertaining to demographic aspects such as population size and adult longevity in the field. On the 6th of August 2017, within a patch of a cloud forest in the municipality of La Celia in Risaralda, Colombia, we recaptured a male specimen of Dichotomius aff. alyattes Harold that was marked 5 years ago, on the 15th of May 2012. The individual was marked with a number 8 on its right elytron and it was recaptured in the same patch forest, which has been sampled since 2008. After an exhaustive review of the field information and literature, this data represents the longest recorded longevity known for Scarabaeinae. Beyond being a fortuitous event, this recapture prompts a review of our ideas regarding the reproductive biology and vulnerability of dung beetle species in landscapes of high anthropic demand, with an emphasis on Neotropical species.

Sigmodontine community and species responses to El Niño and precipitation in different levels of forest degradation.

Few studies have focused on rodent communities at the margins of an ecoregion or the limits of species' distributions, where the community may be more sensitive to extrinsic variables, both biotic and abiotic. This study evaluates sigmodontine rodent species diversity and overall abundance, and variation associated with climatic variables, in three locations with differing levels of habitat degradation. The study was conducted in northeastern Paraguay, near the western limit of the Upper Paraná Atlantic Forest and near the distributional limits of the three most abundant species in the study sites. Three mark-recapture grids were established and classified as least, moderately and most-degraded based on an analysis of several vegetation parameters. The grids were sampled for five consecutive nights, six times during two years. Shannon diversity and overall abundance were calculated for each sample. Monthly Multivariate ENSO Index and rainfall values were obtained from publicly available resources. Product-moment correlations were calculated between community and climatic parameters, including cumulative values for the climatic variables. The same correlations were calculated for the three common sigmodontine species. 1,632 captures were recorded, representing 13 sigmodontine species. Species richness in the samples (one session on one grid) varied from four to seven. Akodon montensis, Hylaeamys megacephalus and Oligoryzomys nigripes were the three most abundant species. In general, species diversity was negatively correlated with ENSO index, precipitation and precipitation anomaly, including cumulative one- to six-month cumulative values of each. Total sigmodontine abundance was positively correlated with the climatic variables. However, these correlations were not uniform among the three levels of habitat degradation, nor did the three abundant species show similar correlation patterns. The three most abundant species are each near their distributional limits, whereas several less abundant species have distributions that extend well beyond the study area. This somewhat counterintuitive result bears further investigation in other sites at ecoregional margins, to determine whether it is a commonly observed pattern, or an exception. Overall sigmodontine abundances were generally reflective of Akodon montensis abundance, which generally correlated with precipitation (including cumulative amounts). Our analyses of these longitudinal data showed two major effects on sigmodontine species diversity and population. First, they are impacted by habitat and secondly, they are affected by climate (ENSO, precipitation). However, individual species are not impacted similarly. Akodon montensis abundances primarily were correlated with abiotic (climatic) variables, and the correlations were consistent across habitats (biotic factors). In contrast, Hylaeamys megacephalus abundance was correlated with climatic variables in two habitats, but not the moderately-degraded habitat, and Oligoryzomys nigripes abundance was not correlated with climate in the most-degraded habitat. Pocos estudios se han centrado en las comunidades de roedores en los márgenes de una ecorregión o en los límites de las distribuciones de las especies, donde la comunidad puede ser más sensible a las variables extrínsecas, tanto bióticas como abióticas. Este estudio evalúa la diversidad de especies y la abundancia general de roedores sigmodontinos, y la variación asociada con las variables climáticas, en tres lugares con diferentes niveles de degradación del hábitat. Se establecieron tres parcelas de captura-marca-recaptura y se clasificaron como la menos, moderada y más degradadas basadas en un análisis de vegetación de varios parámetros. Las parcelas fueron muestreadas durante cinco noches consecutivas, seis veces durante dos años. La diversidad de Shannon y la abundancia general se calcularon para cada muestra. El índice mensual de ENOS multivariable y los valores de precipitación se obtuvieron de sitios accesibles en Internet. Las correlaciones producto-momento se calcularon entre los parámetros climáticos y de la comunidad, incluidos los valores acumulados para las variables climáticas. Se calcularon las mismas correlaciones para las tres especies comunes de sigmodontinos. Se registraron 1,632 capturas, representando 13 especies sigmodontinos. La riqueza de especies en las muestras (una sesión en una parcela) varió de cuatro a siete. Akodon montensis, Hylaeamys megacephalus y Oligoryzomys nigripes fueron las tres especies más abundantes. En general, la diversidad de especies se correlacionó negativamente con el índice ENOS, la precipitación y la anomalía de la precipitación, incluidos los valores acumulativos de uno a seis meses de cada uno. La abundancia total de sigmodontinos se correlacionó positivamente con las variables climáticas. Sin embargo, estas correlaciones no fueron uniformes entre los tres niveles de degradación del hábitat, ni tampoco entre las tres especies abundantes. Las tres especies más abundantes están cada una cerca de sus límites de distribución, mientras que varias especies menos abundantes tienen distribuciones que se extienden mucho más allá de este sitio. Este resultado algo contraintuitivo conlleva una mayor investigación en otros sitios en los márgenes ecorregionales, para determinar si es un patrón observado comúnmente, o una excepción. Las abundancias de sigmodontinos generalmente reflejaron la abundancia de Akodon montensis, que generalmente se correlacionó con la precipitación (incluidas las cantidades acumuladas). Las conclusiones destacadas de este estudio fueron: (1) diferentes niveles de degradación del hábitat se correlacionan con la variación en la diversidad de especies y la abundancia general de los sigmodontinos, y las especies individuales no muestran los mismos niveles de correlación entre los diferentes hábitats; y (2) la variabilidad climática (ENOS y precipitación) también afecta la diversidad de especies sigmodontinos y la abundancia de la población, y las especies comunes no muestran correlaciones similares entre sí. Las abundancias de Akodon montensis se correlacionaron principalmente con variables abióticas (climáticas), y las correlaciones fueron consistentes en todos los hábitats (factores bióticos). En contraste, la abundancia de Hylaeamys megacephalus se correlacionó con las variables climáticas en dos hábitats, pero no en el hábitat moderadamente degradado, y Oligoryzomys nigripes no se correlacionó con el clima en el hábitat más degradado.

Pacific Decadal and El Niño oscillations shape survival of a seabird.

Understanding and modeling population change is urgently needed to predict effects of climate change on biodiversity. High trophic-level organisms are influenced by fluctuations of prey quality and abundance, which themselves may depend on climate oscillations. Modeling effects of such fluctuations is challenging because prey populations may vary with multiple climate oscillations occurring at different time scales. The analysis of a 28-yr time series of capture-recapture data of a tropical seabird, the Nazca Booby (Sula granti), in the Galápagos, Ecuador, allowed us to test for demographic effects of two major ocean oscillations occurring at distinct time-scales: the inter-annual El Niño Southern Oscillation (ENSO) and inter-decadal oscillations. As expected for a tropical seabird, survival of fledgling birds was highly affected by extreme ENSO events; by contrast, neither recruitment nor breeding participation were affected by either ENSO or decadal oscillations. More interesting, adult survival, a demographic trait that canalizes response to environmental variations, was unaffected by inter-annual ENSO oscillations yet was shaped by the Pacific Decadal Oscillation and small pelagic fish regime. Adult survival decreased during oceanic conditions associated with higher breeding success, an association probably mediated in this species by costs of reproduction that reduce survival when breeding attempts end later. To our knowledge, this is the first study suggesting that survival of a vertebrate can be vulnerable to a natural multidecadal oscillation.

Annual Abundance and Population Structure of Two Dung Beetle Species in a Human-Modified Landscape.

Population studies are essential for understanding different aspects of species' biology, estimating extinction probability, and determining evolutionary and life history. Using the mark-recapture method, we studied the abundance and population structure of dung beetle species (Deltochilum mexicanum and Dichotomius satanas) over one year in a human-modified landscape in Mexico. We captured 1960 individuals with a net recapture rate of 11%. Deltochilum mexicanum had a higher rate of recapture (14%) than Dichotomius satanas (5%). Annual variation in abundance was similar for both species, with maximum abundance occurring in summer and a marked reduction during winter. Deltochilum mexicanum was dominant inside the forest, and its abundance was influenced by vegetation cover, temperature, and humidity. Dichotomius satanas was more frequent outside the forest, and none of the considered environmental variables affected its abundance. The adult sex ratio of Deltochilum mexicanum was female-biased, whereas that of Dichotomius satanas was male-biased. The maximum estimated population size was similar for both species, but Deltochilum mexicanum had a higher number of new individuals and survival rate. Since species with different biological attributes presented a similar pattern of abundance and population structure, we conclude that environmental conditions are the main regulator of dung beetle populations in the human-modified landscape.

Sex-specific early survival drives adult sex ratio bias in snowy plovers and impacts mating system and population growth.

Adult sex ratio (ASR) is a central concept in population biology and a key factor in sexual selection, but why do most demographic models ignore sex biases? Vital rates often vary between the sexes and across life history, but their relative contributions to ASR variation remain poorly understood-an essential step to evaluate sex ratio theories in the wild and inform conservation. Here, we combine structured two-sex population models with individual-based mark-recapture data from an intensively monitored polygamous population of snowy plovers. We show that a strongly male-biased ASR (0.63) is primarily driven by sex-specific survival of juveniles rather than adults or dependent offspring. This finding provides empirical support for theories of unbiased sex allocation when sex differences in survival arise after the period of parental investment. Importantly, a conventional model ignoring sex biases significantly overestimated population viability. We suggest that sex-specific population models are essential to understand the population dynamics of sexual organisms: reproduction and population growth are most sensitive to perturbations in survival of the limiting sex. Overall, our study suggests that sex-biased early survival may contribute toward mating system evolution and population persistence, with implications for both sexual selection theory and biodiversity conservation.

Potamodromous migrations in the Magdalena River basin: bimodal reproductive patterns in neotropical rivers.

Magdalena River basin potamodromous fishes have two annual reproductive seasons: the subienda in the first half of the year and the mitaca in the second. Both upstream migrations are c. 30-45 days long; after that, with the onset of the rainy season, fishes spawn and remain in the river (resident individuals) or start a downstream movement (the bajanza) to return to the Magdalena floodplain lakes (nursery, shelter and feeding grounds). Due to their particular gonad development the bocachico Prochilodus magdalenae and probably the comelón Leporinus muyscorum are physiologically able to undertake two annual basin migrations. In the presence of dams or hydropower structures, fishes are able to find alternative migration routes. Some species should be re-classified in their migratory behaviour.

Using genetic inference to re-evaluate the minimum longevity of the lemon shark Negaprion brevirostris.

A combination of mark-recapture and genetic sampling was used to extend the minimum longevity of an elasmobranch species and the life span estimate of the lemon shark Negaprion brevirostris was increased conservatively from 20·2 to 37 years. This increase in longevity means higher vulnerability and a longer recovery time from exploitation.

Long-distance movement by a great fruit-eating bat, Artibeus lituratus (Olfers, 1818), in southeastern Brazil (Chiroptera, Phyllostomidae): evidence for migration in Neotropical bats? / Deslocamento de longa distância por um grande morcego frugívoro, Artibeus lituratus (Olfers, 1818), no sudeste do Brasil (Chiroptera, Phyllostomidae): evidência de migração de morcegos Neotropicais?

In Brazil, bat migrations have been inferred based on seasonal variations in bat abundances observed for several species, probably as a result of variations in temperature and food availability. However, direct evidence of individual medium to long distance (> 10 km) movements, based on marked specimens, is restricted to large frugivorous bats, genus Artibeus (Phyllostomidae). We report the longest bat movement recorded in Brazil, along 113 km in a straight line, difference in altitude of 738 m, from a mixed Araucaria forest in Curitiba, PR, to the Atlantic Forest, Alto Ribeira, SP, by a female Artibeus lituratus (Olfers, 1818), over a period of 14 months. This data is consistent with the occurrence of migratory movements in Neotropical bats, such as the ecologically flexible Artibeus spp., over relatively large areas, probably with short stopover foraging intervals. Implications for the conservation of these bats are clear, as their home ranges may be much larger than their foraging areas, encompassing more than one biome and overcoming political borders.

Migrações em morcegos brasileiros têm sido inferidas a partir de variações sazonais nas abundâncias regionais das populações, provavelmente condicionadas por flutuações na temperatura e na disponibilidade de alimento. No entanto, registros de deslocamentos individuais de média a longa distância, ultrapassando suas áreas domiciliares (> 10 km), comprovados através de marcação e recaptura, são restritos aos grandes morcegos frugívoros do gênero Artibeus (Phyllostomidae). Registramos, aqui, o maior deslocamento já publicado, de ca. 113 km em linha reta, entre localidades com diferença de altitude de 738 m, respectivamente em floresta mista de araucárias, região de Curitiba, PR, e em Mata Atlântica, Alto Ribeira, SP, realizado por uma fêmea de Artibeus lituratus (Olfers, 1818), em um intervalo máximo de 14 meses. Este dado é consistente com a ocorrência de movimentos migratórios em Artibeus spp. ao longo de áreas bastante extensas, provavelmente através de várias etapas de forrageio. As implicações para a conservação desses quirópteros são claras, uma vez que os animais desta espécie podem ter áreas de vida bem maiores que suas áreas domiciliares (de forrageio), abrangendo mais de um bioma e ultrapassando limites geopolíticos.

Photo-identification as a simple tool for studying invasive lionfish Pterois volitans populations.

Photo-tagging, i.e. using a specific software to match colour patterns on photographs, was tested as a means to identify individual Indo-Pacific Pterois volitans to assist with population and movement studies of this invasive species. The stripe pattern on the flank of adult P. volitans (n = 48) was the most individually distinctive of three body regions tested, leading to correct individual identification on 68 and 82% of tests with a single and two images of the reference individual, respectively. Photo-tagging is inexpensive, logistically simple and can involve citizen scientists, making it a viable alternative to traditional tagging to provide information on P. volitans distribution, movement patterns and recolonization rates after removals.

Photo-identification as a technique for recognition of individual fish: a test with the freshwater armored catfish Rineloricaria aequalicuspis Reis & Cardoso, 2001 (Siluriformes: Loricariidae)

Photo-identification allows individual recognition of animal species based on natural marks, being an alternative to other more stressful artificial tagging/marking techniques. An increasing number of studies with different animal groups has shown that photo-identification can successfully be used in several situations, but its feasibility to study freshwater fishes is yet to be explored. We demonstrate the potential use of photo-identification for intraspecific recognition of individuals in the stream-dwelling loricariid Rineloricaria aequalicuspis . We tested photo-identification in laboratory and field conditions based on the interindividual variability in abdominal bony plates. Our test yielded high correct matches in both laboratory (100%) and field conditions (> 97%), comparable to other reliable techniques and to studies that successfully used photo-identification in other animals. In field conditions, the number of correct matches did not differ statistically between computer-assisted and naked-eye identification. However, the average time expended to conclude computer-assisted photo evaluations was about half of the time expended to conclude naked-eye evaluations. This result may be exacerbated when using database with large number of images. Our results indicate that photo-identification can be a feasible alternative technique to study freshwater fish species, allowing for a wider use of mark-recapture in ecological and behavioral studies.(AU)

A foto-identificação permite o reconhecimento individual de espécies de animais baseando-se em marcas naturais, sendo uma alternativa a outras técnicas de marcação artificial mais estressantes comumente usadas. O número crescente de estudos que usam foto-identificação em diferentes grupos animais mostra que esta técnica pode ser utilizada com sucesso, mas a viabilidade em estudos com peixes de água doce ainda não foi avaliada. Nós demonstramos o uso potencial da foto-identificação para o reconhecimento individual de peixes com indivíduos do loricarídeo Rineloricaria aequalicuspis. Nós testamos foto-identificação em condições de laboratório e de campo com base na variabilidade inter-individual das placas ósseas abdominais. O teste resultou em elevada porcentagem de acerto nas comparações, tanto para a condição de laboratório (100%) quanto para a de campo (> 97%), o que é comparável com outras técnicas confiáveis e com outros estudos que empregaram foto-identificação com sucesso. No teste de campo, o número de acertos não diferiu estatisticamente entre auxílio de computador e olho nu. Entretanto, o tempo médio despendido para concluir as avaliações com o auxílio de computador foi cerca da metade do tempo despendido para as avaliações a olho nu. Esse resultado pode ser exacerbado em avaliações com um grande número de imagens. Nossos resultados indicam que a foto-identificação pode ser uma técnica alternativa viável para estudar peixes de água doce e possibilita um uso mais amplo da marcação e recaptura para estudos ecológicos e comportamentais.(AU)

Photo-identification as a technique for recognition of individual fish: a test with the freshwater armored catfish Rineloricaria aequalicuspis Reis & Cardoso, 2001 (Siluriformes: Loricariidae)

Photo-identification allows individual recognition of animal species based on natural marks, being an alternative to other more stressful artificial tagging/marking techniques. An increasing number of studies with different animal groups has shown that photo-identification can successfully be used in several situations, but its feasibility to study freshwater fishes is yet to be explored. We demonstrate the potential use of photo-identification for intraspecific recognition of individuals in the stream-dwelling loricariid Rineloricaria aequalicuspis . We tested photo-identification in laboratory and field conditions based on the interindividual variability in abdominal bony plates. Our test yielded high correct matches in both laboratory (100%) and field conditions (> 97%), comparable to other reliable techniques and to studies that successfully used photo-identification in other animals. In field conditions, the number of correct matches did not differ statistically between computer-assisted and naked-eye identification. However, the average time expended to conclude computer-assisted photo evaluations was about half of the time expended to conclude naked-eye evaluations. This result may be exacerbated when using database with large number of images. Our results indicate that photo-identification can be a feasible alternative technique to study freshwater fish species, allowing for a wider use of mark-recapture in ecological and behavioral studies.

A foto-identificação permite o reconhecimento individual de espécies de animais baseando-se em marcas naturais, sendo uma alternativa a outras técnicas de marcação artificial mais estressantes comumente usadas. O número crescente de estudos que usam foto-identificação em diferentes grupos animais mostra que esta técnica pode ser utilizada com sucesso, mas a viabilidade em estudos com peixes de água doce ainda não foi avaliada. Nós demonstramos o uso potencial da foto-identificação para o reconhecimento individual de peixes com indivíduos do loricarídeo Rineloricaria aequalicuspis. Nós testamos foto-identificação em condições de laboratório e de campo com base na variabilidade inter-individual das placas ósseas abdominais. O teste resultou em elevada porcentagem de acerto nas comparações, tanto para a condição de laboratório (100%) quanto para a de campo (> 97%), o que é comparável com outras técnicas confiáveis e com outros estudos que empregaram foto-identificação com sucesso. No teste de campo, o número de acertos não diferiu estatisticamente entre auxílio de computador e olho nu. Entretanto, o tempo médio despendido para concluir as avaliações com o auxílio de computador foi cerca da metade do tempo despendido para as avaliações a olho nu. Esse resultado pode ser exacerbado em avaliações com um grande número de imagens. Nossos resultados indicam que a foto-identificação pode ser uma técnica alternativa viável para estudar peixes de água doce e possibilita um uso mais amplo da marcação e recaptura para estudos ecológicos e comportamentais.