Comparison of dispersal ability between the green leafhoppers,Nephotettix virescens andN. cincticeps (hemiptera: Cicadellidae) by tethered flight

Dispersal propensity of green leafhoppers was compared between a tropical species, Nephotettix virescens, and a temperate species, N. cincticeps. The flight ability was measured with tethered flight technique under laboratory conditions (25°C, 16L-8D). The pre-flight period was shorter and the flight duration was longer in N. virescens than in N. cincticeps in both sexes. No significant correlations were found between the flight activity and morphometric characters for either of the two species. The results suggested that dispersal propensity of N. virescens is higher than that of N. cincticeps.     

Genetic inference of orchid population dynamics on different-aged lava flows in Costa Rica

Colonization is a fundamental ecological process that is important for the persistence of species, particularly when a changing environment necessitates range shifts. Vacant habitats available for colonization often arise from landscape disturbance. Colonization and population expansion processes can be inferred by examining the levels and spatial distribution of genetic variation of plant populations with known disturbance histories. Samples (N = 690) of the terrestrial orchid, Epidendrum radicans, were collected from five lava flow sites on the slopes of Volcán Arenal in Costa Rica that last experienced major eruptions in 1968 and 1992. Individuals were also sampled (N = 188) from four regional populations. Samples were characterized using 15 nuclear genetic markers and analyzed using population genetics statistics. Genetic diversity within sites was moderate (H_e = 0.092–0.192). Contrary to expectation, diversity tended to be lower on the older lava flows (0.131 vs. 0.172) which may reflect their more sheltered topography that restricted pollen/seed immigration, and/or greater intra- and interspecific competition. Genetic diversity measures indicate that the lava flows were colonized by numerous individuals that likely originated from multiple sources while spatial genetic structure (SGS) statistics indicate that most recruitment in the study sites subsequent to colonization resulted from in situ reproduction and localized seed deposition. Younger sites had significantly greater SGS over larger distances which reflects fewer reproductive events, and less spatial and temporal overlap of seed shadows relative to the older sites. Clones were also generally smaller on the younger sites (≤3 m vs. ≤8 m).     

Limited genetic differentiation of Mycetomoellerius mikromelanos in Parque National Soberanía,Panama: Implications for queen dispersal

The coevolutionary relationship between fungus-growing ants (Formicidae: Attini: Attina) and their symbionts has been well studied in the Panamanian rain forests. To further understand the ecological context of these evolutionary relationships, we have examined the population-genetic structure of the fungus-growing ant species Mycetomoellerius mikromelanos Cardenas, Schultz, Adams 2021 in the Panama Canal Zone. We specifically investigated the presence of population structure, the significance of geographic features (i.e., creeks) limiting gene flow, and relatedness between ant colonies. To accomplish this, we genotyped 85 ant colonies from nine creeks across an approximately 30 km transect in Parque National Soberanía, Panama, using double-digest restriction-site-associated DNA sequencing. We did not find distinct population structure using two genetic clustering methods; however, we did detect an effect of isolation by distance. Furthermore, related colonies were frequently detected on the same creek or neighboring creeks, and some at further geographic distances. Collectively, these findings demonstrate that new colonies tend to establish on natal creeks and occasionally on distant creeks following long-distance dispersal events. We discuss how population-genetic patterns reveal the natural history of M. mikromelanos in Parque National Soberanía and how these results fit into the context of fungus-growing ant mutualisms. Abstract in Spanish is available with online material.     

Vertically stratified frugivore community composition and interaction frequency in a liana fruiting across forest strata

Vertical stratification is a key feature of tropical forests and structures plant–frugivore interactions. However, it is unclear whether vertical differences in plant-frugivore interactions are due to differences among strata in plant community composition or inherent preferences of frugivores for specific strata. To test this, we observed fruit removal of a diverse frugivore community on the liana Marcgravia longifolia in a Peruvian rain forest. Unlike most other plants, Marcgravia longifolia produces fruits across forest strata. This enabled us to study effects of vertical stratification on fruit removal without confounding effects of plant species and stratum. We found a high number of visits of a few frugivore species in the understorey and a low number of visits of many different frugivores in the canopy and midstorey. Whereas partial and opportunistic frugivores foraged across strata with differing frequencies, obligate frugivores were only found eating fruits in the higher strata. Avian frugivores foraging in the canopy were mainly large species with pointed wings, whereas under- and midstorey avian foragers were smaller with rounded wings. Our findings suggest a continuous shift in the frugivore community composition along the vertical gradient, from a few generalized frugivores in the understorey to a diverse set of specialized frugivores in the canopy. This shift in the frugivore community leads to correlated, reciprocal changes from specialized to generalized plant-frugivore interactions. Thus, we conclude that vertical niche differentiation between species in tropical forests persists even when food resources are available across strata. This highlights its role for promoting biodiversity and ecosystem functioning.     

The structure of a local population and dispersal pattern in the Styan's grasshopper warbler,Locustella pleskei

The breeding sites of Styan's grasshopper warblers are restricted to small islands and distributed discretely. The study on the marked population was conducted on two islets, Okitsu-jima and Ohtsukue-jima, located near Fukuoka, Japan, from 1981 to 1989. About 20 and 70 birds bred on the two islets, respectively, and the mean density of breeding pairs was 25.5 ha⁻¹. The dispersal pattern and population, structure were examined. Adult birds returned to the same breeding site. Males always reoccupied the same territory as in previous years but females not. Males were more philopatric and only female yearlings dispersed over long distances and moved between the breeding sites in Hakata Bay. The returning rate was 0.57 for adults, and 0.21 for juveniles. The age distribution of birds at Ohtsukue-jima was almost stable, while that at Okitsu-jima was unstable because it was a marginal habitat for the birds. Estimating from the dispersal pattern and age structure of this warbler the population near Fukuoka consists of only four islets and is almost stable.     

Antiproliferative Activity and Ultrastructural Changes in Promastigote and Amastigote forms of Leishmania amazonensis Caused by Limonene-Acylthiosemicarbazide Hybrids

Leishmaniasis is a tropical zoonotic disease. It is found in 98 countries, with an estimated 1.3 million people being affected annually. During the life cycle, the Leishmania parasite alternates between promastigote and amastigote forms. The first line treatment for leishmaniasis are the pentavalent antimonials, such as N-methylglucamine antimoniate (Glucantime®) and sodium stibogluconate (Pentostam®). These drugs are commonly related to be associated with dangerous side effects such as cardiotoxicity, nephrotoxicity, hepatotoxicity, and pancreatitis. Considering these aspects, this work aimed to obtain a new series of limonene-acylthiosemicarbazides hybrids as an alternative for the treatment of leishmaniasis. For this, promastigotes, axenic amastigotes, and intracellular amastigotes of Leishmania amazonensis were used in the antiproliferative assay; J774-A1 macrophages for the cytotoxicity assay; and electron microscopy techniques were performed to analyze the morphology and ultrastructure of parasites. ATZ−S-04 compound showed the best result in both tests. Its IC₅₀, in promastigotes, axenic amastigotes and intracellular amastigotes was 0.35±0.08 μM, 0.49±0.06 μM, and 15.90±2.88 μM, respectively. Cytotoxicity assay determined a CC₅₀ of 16.10±1.76 μM for the same compound. By electron microscopy, it was observed that ATZ−S-04 affected mainly the Golgi complex, in addition to morphological changes in promastigote forms of L. amazonensis.     

失眠障碍患者脑部CT影像学变化与学习记忆功能变化、临床特征相关性分析

摘要 目的：探讨失眠障碍患者脑部CT影像学变化与学习记忆功能变化、临床特征相关性。方法：回顾性选择2018年6月至2021年6月来我院诊治的失眠障碍患者50例,选择同期来我院体检的健康人群30例。两组受试者均使用飞利浦64排CT进行扫描,检测计算额角指数与海马指数,对比两组受试者的额角指数、海马指数,对比两组受试者的临床记忆评分、睡眠质量评分、WCST评分,分析两组受试者的临床症状,分析观察组患者额角指数、海马指数与临床记忆评分、睡眠指数评分、WCST评分、临床症状评分的相关性。结果：观察组的额角指数、海马指数明显较对照组低（P<0.05）。观察组的临床记忆评分明显较对照组低（P<0.05）。观察组的睡眠质量评分明显较对照组低（P<0.05）。观察组的完成测验数、选择错误率、完成第一个应答数、持续错误率、错误应答数明显较对照组高,完成分类数、概念化水平百分比明显较对照组低（P<0.05）。观察组的躯体感觉评分及心理感觉评分明显较对照组高（P<0.05）。额角指数、海马指数与临床记忆评分呈正比,与睡眠质量评分、临床症状评分呈反比,与WCST评分中的完成分类数、概念化水平百分比呈正比,与WCST评分中的完成测验数、选择错误率、完成第一个应答数、持续错误率、错误应答数呈反比（P<0.05）。结论：脑部CT影像学结果发现,失眠障碍存在学习记忆功能变化,与患者的临床特征相关性、睡眠质量存在存在一定相关性。     

Stream channel experiments on downstream movement of recently emerged trout, Salmo trutta L. and salmon, S. salar L.—I. Effect of four different water velocity treatments upon dispersal rate

Four experimental stream channels were used to study instantaneous downstream dispersal rates of young trout, Salmo trutta L., and salmon, S. salur L ., relative to four different water velocities.
Young salmon showed a high rate of dispersal at a low velocity of 7.5 cm s⁻¹ and lower rates at higher velocities of 25 to 70cm s⁻¹. Trout showed their lowest rate at 25cm s⁻¹ with a slightly higher rate at 7.5 cm s⁻¹ and increasingly higher rates at velocities in excess of 25 cm s⁻¹. These results are consistent with field observations on the velocity preferences of young trout and salmon.     

Roosting Requirements of Two Frugivorous Bats (Sturnira lilium and Arbiteus intermedius) in Fragmented Neotropical Forest1

As tropical forest fragmentation accelerates, scientists are concerned with the loss of species, particularly those that play important ecological roles. Because bats play a vital role as the primary seed dispersers in cleared areas, maintaining healthy bat populations is critical to natural forest regeneration. Observations of foraging bats suggest that many Neotropical fruit‐eating species have fairly general habitat requirements and can forage in many different kinds of disturbed vegetation; however, their roosting requirements may be quite different. To test whether or not general foraging requirements are matched by equally broad roosting requirements, we used radiotelemetry to locate roost sites of two common frugivorous bat species (Sturnira lilium and Artibeus intermedius) in a fragmented forest in southeastern Mexico. Sturnira lilium roosted inside tree cavities and selected large‐diameter roost trees in remnant patches of mature forest. Fewer than 2 percent of trees surveyed had a mean diameter equal to or greater than roost trees used by . S. lilium, Artibeus intermedius roosted externally on branches and vines and under palm leaves and selected roost trees of much smaller diameter. Compared to random trees, roost trees chosen by A. intermedius were closer to neighboring taller trees and also closer in height to these trees. Such trees likely provide cryptic roosts beneath multiple overlapping crowns, with sufficient shelter from predators and the elements. While males of A. intermedius generally roosted alone in small trees within secondary forest, females roosted in small groups in larger trees within mature forest and commuted more than three times farther than males to reach their roost sites. Loss of mature forest could impair the ability of frugivorous bats to locate suitable roost sites. This could have a negative impact on bat populations, which in turn could decrease forest regeneration in impacted areas.