Large Nests Research Articles

Sequential Subterranean Transport of Excavated Sand and Foraged Seeds in Nests of the Harvester Ant, Pogonomyrmex badius.

During their approximately annual nest relocations, Florida harvester ants (Pogonomyrmex badius) excavate large and architecturally-distinct subterranean nests. Aspects of this process were studied by planting a harvester ant colony in the field in a soil column composed of layers of 12 different colors of sand. Quantifying the colors of excavated sand dumped on the surface by the ants revealed the progress of nest deepening to 2 m and enlargement to 8 L in volume. Most of the excavation was completed within about 2 weeks, but the nest was doubled in volume after a winter lull. After 7 months, we excavated the nest and mapped its structure, revealing colored sand deposited in non-host colored layers, especially in the upper 30 to 40 cm of the nest. In all, about 2.5% of the excavated sediment was deposited below ground, a fact of importance to sediment dating by optically-stimulated luminescence (OSL). Upward transport of excavated sand is carried out in stages, probably by different groups of ants, through deposition, re-transport, incorporation into the nest walls and floors and remobilization from these. This results in considerable mixing of sand from different depths, as indicated in the multiple sand colors even within single sand pellets brought to the surface. Just as sand is transported upward by stages, incoming seeds are transported downward to seed chambers. Foragers collect seeds and deposit them only in the topmost nest chambers from which a separate group of workers rapidly transports them downward in increments detectable as a "wave" of seeds that eventually ends in the seed chambers, 20 to 80 cm below the surface. The upward and downward transport is an example of task-partitioning in a series-parallel organization of work carried out by a highly redundant work force in which each worker usually completes only part of a multi-step process.

Socially selected ornaments and fitness: Signals of fighting ability in paper wasps are positively associated with survival, reproductive success, and rank.

Many animals have ornaments that mediate choice and competition in social and sexual contexts. Individuals with elaborate sexual ornaments typically have higher fitness than those with less elaborate ornaments, but less is known about whether socially selected ornaments are associated with fitness. Here, we test the relationship between fitness and facial patterns that are a socially selected signal of fighting ability in Polistes dominula wasps. We found wasps that signal higher fighting ability have larger nests, are more likely to survive harsh winters, and obtain higher dominance rank than wasps that signal lower fighting ability. In comparison, body weight was not associated with fitness. Larger wasps were dominant over smaller wasps, but showed no difference in nest size or survival. Overall, the positive relationship between wasp facial patterns and fitness indicates that receivers can obtain diverse information about a signaler's phenotypic quality by paying attention to socially selected ornaments. Therefore, there are surprisingly strong parallels between the information conveyed by socially and sexually selected signals. Similar fitness relationships in social and sexually selected signals may be one reason it can be difficult to distinguish the role of social versus sexual selection in ornament evolution.

Size and condition of bamboo as structural factors behind the vertical stratification of the bamboo-nesting ant community

Nest-site limitation is an important factor regulating ant diversity, particularly at low elevations. In savannas, trees and shrubs do not support large nests in their crowns and cavities for nest sites are limited. However, bamboos are very common and can provide vertically stacked hollow chambers for ants to establish their colonies. We evaluated the bamboo species Guadua paniculata as a source of nest cavities for ants in the Cerrado (Brazilian savanna). We hypothesized that the morphology of this bamboo species and its vertical arrangement regulate the distribution of ants nesting in it. Thirty bamboo patches distributed among four sites in the state of Tocantins (Brazil) were evaluated, in which 36 species of ants occupied more than half of the bamboo available. Wider and longer culms enabled a greater number of colonies of several ant species. Living or dead condition of bamboo had a significant effect on the diversity and composition of the ant fauna. Dead culms were occupied opportunistically by several generalist species, while Azteca fasciata dominated living bamboo. Finally, we observed the species distribution along a vertical gradient of bamboo height, and proposed that differential colonization of ground and canopy-dwelling species and habitat specialization may be key mechanisms for the observed pattern of distribution. This study contributes to a better understanding of species coexistence in low elevation forests in the Brazilian Cerrado by considering bamboo nest sites as a key factor affecting ant diversity.

Dermoscopic features of small size pigmented basal cell carcinomas.

Dermoscopic images of histologically proven pigmented basal cell carcinomas (BCC) were retrospectively assessed to compare the dermoscopic features of BCC of 3 mm or less in diameter (n = 6) with BCC of 4-6 mm in diameter (n = 11). All lesions lacked the presence of a pigment network. BCC with a diameter of 3 mm or less had fewer positive dermoscopic features compared with the 4-6 mm in diameter BCC. Multiple blue-gray globules and large blue-gray ovoid nests were frequently present. Dermoscopy is a useful tool for early diagnosis of pigmented BCC, even when they are small.

Large Nested Variant of Urothelial Carcinoma - A Case Report: Do Not Judge This Book by Its Cover - This Tumor Is a Wolf in Sheep's Clothing

Large nested variant of urothelial carcinoma (LNVUC) is a rare and relatively recently described subtype of urothelial carcinoma by Cox et al (2011), with …

Diagnosis of Gleason pattern 5 prostate adenocarcinoma on core needle biopsy: an interobserver reproducibility study among urologic pathologists.

Accurate recognition of Gleason pattern 5 (GP5) prostate adenocarcinoma on needle biopsy is critical as it is associated with disease progression and adverse clinical outcome. Despite important implications of this diagnosis, interobserver variation in the diagnosis of GP5 has not been adequately studied. Digital images of 66 prostate adenocarcinoma cases that potentially contained a GP5 component were distributed to 16 urologic pathologists who were asked to classify whether GP5 was present. Each image was initially classified into 1 of 4 morphologic subpatterns by 2 coauthors (R.B.S. and M.Z.): solid nests (15), comedocarcinoma (8), single cells and/or cords (35), and variant morphology (8). Additional features captured included: size (large: >20 cells, medium: 10 to 20 cells, and small: <10 cells) and distribution of nuclei (uniform vs. nonuniform) for nests pattern; intraluminal coagulative tumor necrosis, karyorrhectic debris, and amorphous material for comedocarcinoma pattern; and quantity (≤5, 6 to 10, and >10) and distribution (clustered vs. intermixed with adjacent well-formed glands) for single cells/cords pattern. Interobserver reproducibility of a diagnosis of GP5 was assessed and the morphologic subpatterns and features were correlated with the consensus diagnosis (defined as 75% agreement). Interobserver reproducibility for overall diagnostic agreement was fair (κ=0.376). Among subpatterns, comedocarcinoma had highest reproducibility (κ=0.499), followed by variant morphology (κ=0.443), single cells/cords (κ=0.369), and nests (κ=0.347). All cases with the following features achieved consensus for GP5: large nests regardless of nuclear distribution; coagulative necrosis with or without karyorrhectic debris; single cells/cords >10 or 6 to 10 in a cluster; and signet ring-like cells in single cells or within nests pattern. A majority of cases with the following features achieved consensus against GP5: medium-size nests; exclusive intraluminal amorphous material; single cells/cords ≤5; and Paneth cell change. Remaining morphologic features did not reach consensus for or against GP5. A majority (86%) of participants would diagnose a small focus of GP5 only when it is present in >1 level. The diagnostic reproducibility of GP5 within certain morphologies was only fair among urologic pathologists. However, the diagnosis of GP5 was more reproducible when certain restrictive morphologic and quantitative criteria were applied. These findings suggest that additional studies are needed to find highly reproducible features of GP5 associated with documented aggressive clinical outcome.

Dermoscopy of tumours arising in naevus sebaceous: a morphological study of 58 cases.

Naevus sebaceous is a congenital hamartoma commonly associated with the development of secondary neoplasms. There are sparse data relating to the dermoscopy of tumours arising in naevus sebaceous. To evaluate the dermoscopic features of a large series of neoplasms arising in naevus sebaceous. Digital dermoscopic images of 58 histopathologically confirmed cases of secondary neoplasms arising in naevus sebaceous collected from 11 hospitals in Spain, France, Italy and Austria were evaluated for the presence of dermoscopic structures and patterns. The most frequent tumours collected were: trichoblastoma (39.6%), basal cell carcinoma (20.7%) and syringocystadenoma papilliferum (15.6%). The most remarkable findings were: (i) the pattern composed of asymmetrical large blue-grey ovoid nests was more common in basal cell carcinomas than in trichoblastoma (58.3% vs. 4.3%; P<0.001) and the pattern composed of a symmetrical total large blue-grey ovoid nest (a blue-grey homogeneous area which occupies the whole lesion) was more common in trichoblastoma (82.6% vs. 16.6%; P<0.001); (ii) the most frequent pattern associated with syringocystadenoma papilliferum was a symmetric, erythematous lesion with exophytic papillary structures, ulceration and vessels (55.5%); (iii) the most common pattern associated with apocrine hidrocystomas was a total symmetric homogeneous area and arborizing telangiectasias (60%). Benign adnexal tumours associated with naevus sebaceous are dermoscopic mimickers of basal cell carcinomas. A pigmented nodule arising in a naevus sebaceous with a total blue large ovoid nest on dermoscopy could be a trichoblastoma, basal cell carcinoma, hidrocystoma or hidradenoma. Dermoscopy can be a useful diagnostic tool which generates a more accurate preoperative diagnosis.

Nest size preferences and aggression in sand gobies (Pomatoschistus minutus)

In animal competition, resource holding potential (RHP) and resource value are two important factors determining the level of aggression and the outcome of contests. One valuable resource among nest-brooding animals that is subject to intense competition is a suitable nest substrate. Sand goby males (Pomatoschistus minutus) rely on finding good nest substrates, but the strategies vary between regions. We first investigated the nest size preferences in sand gobies from Kalmar Sound, a brackish area of the Baltic Sea with a shortage of suitable shells for nest construction and few invertebrate nest predators. Males expressed clear preference for larger nest substrates regardless of the male’s own size. To manipulate resource value, we provided males with large or small nests and tested if this and/or RHP affected aggression during nest defence. Resource value (a preferred large nest vs an unpreferred small nest) had no effect on aggression. However, RHP (total length of the resident male) had a significant effect. Larger males were more aggressive than smaller ones when matched against an opponent of the same size, suggesting that resident males acted according to own RHP.

Large increase in nest size linked to climate change: an indicator of life history, senescence and condition

Many animals build extravagant nests that exceed the size required for successful reproduction. Large nests may signal the parenting ability of nest builders suggesting that nests may have a signaling function. In particular, many raptors build very large nests for their body size. We studied nest size in the goshawk Accipiter gentilis, which is a top predator throughout most of the Nearctic. Both males and females build nests, and males provision their females and offspring with food. Nest volume in the goshawk is almost three-fold larger than predicted from their body size. Nest size in the goshawk is highly variable and may reach more than 600 kg for a bird that weighs ca. 1 kg. While 8.5% of nests fell down, smaller nests fell down more often than large nests. There was a hump-shaped relationship between nest volume and female age, with a decline in nest volume late in life, as expected for senescence. Clutch size increased with nest volume. Nest volume increased during 1977-2014 in an accelerating fashion, linked to increasing spring temperature during April, when goshawks build and start reproduction. These findings are consistent with nest size being a reliable signal of parental ability, with large nest size signaling superior parenting ability and senescence, and also indicating climate warming.

Resource requirements of parrots: nest site selectivity and dietary plasticity of Psittaciformes

Parrots (Order Psittaciformes) are secondary cavity-nesters that depend on existing cavities for nest sites, and consume plant resources of fruits, seeds, and flowers that are highly variable, but little is known of resource selectivity by parrots, or how they deal with variable environments. We reviewed published studies of nest-cavity use by parrots, and those evaluating parrot diet and their relationship with food resources. Most studies have been conducted within the last 20 years and these present data on resource use for only one-third of parrot species worldwide. However, basic information on resource requirements is lacking for the vast majority of Psittaciformes, particularly for species from the Asian region. Nesting studies have found that parrots use nest cavities in large trees, high above the ground, with large nest chambers, of 0.5–1 m deep, and entrance diameters related to body size of the parrot species. A few studies demonstrate that parrots select nest sites based on cavity characteristics, which may influence nest success, but a complete evaluation of adaptive nest site selection by Psittaciformes is lacking. Parrots have varied diets and may employ a combination of strategies of diet switching, habitat shifts, and movements to track food resources. This plasticity in diet and foraging strategy may influence the extent to which parrots can respond to anthropogenic pressures of global change. Parrots may also play an important functional role in forest ecosystems, yet little is currently known of plant–animal interactions of parrots, or the impact of parrot populations on forest dynamics. Based on our review of the literature, we suggest that to meet their resource requirements, parrots employ resource selection strategies of hierarchical nest site selection to increase the likelihood of nest success, and plasticity in diet and foraging strategy to track variable food resources. Future studies need to evaluate resource selection and the consequences of this for fitness in order to assess the potential impacts of global change on parrot populations, and to identify characteristics which make species vulnerable to human pressures.

Stable Isotope Signatures Reveal Cryptic Differences in Diet of Sociable Weavers

Foraging habits of animals are a critical component of their ecology; however, estimates of feeding that rely solely on observation may not detect all of the factors that affect foraging decisions. Importantly, few studies have examined the influence of sociality on dietary regimes in avian species. The stable isotope ratios of carbon (δ13Q and nitrogen (δ15N) were used to assess the foraging habits of Sociable Weavers ( Philetairus socius) at a field site in Namibia. Sociable Weavers were sampled from three different nests, at two different time points over the course of a year. We found significant differences in stable isotope composition between nests, and subsequently compared the isotopic profile to the isotopic profile of the preferred food item. Isotopic structuring between nests suggests that sociality may constrain foraging decisions and could be a common feature of species of animals where foraging groups are temporally stable. We also found that larger nests are more isotopically similar to the preferred foraging source, and thus larger populations may be supported by nearby foraging resources.

Nest-Site Selection and Reproductive Success of the Little GrebeTachybaptus ruficollisin Northeast Algeria

We studied the phenology, habitat selection, and interannual and seasonal changes in breeding performance of the little grebe Tachybaptus ruficollis in relation to the spatial structure of a shallow lake during three breeding seasons (2010–2012). Nests were mostly located in shallow waters, close to the shore (98.3 ± 37.9 cm), in vegetation dominated by Scirpus lacustris. The egg-laying period started at the end of March and extended for four months until the end of July. Overall, the mean clutch size was 4.7 ± 1.1 (N = 154) with a modal clutch of 5. There was a seasonal decline in both egg volume and clutch size. The overall nesting success was 60% and the chief causes of nest failure were predation (52%) and adverse weather (20%). Breeding outcome was influenced by water depth, nest size and year of breeding. Predation and nest flooding markedly varied between years. Larger nests had a higher nesting success than smaller ones. Likewise, nests located at greater water depth (further from the shore) succeeded better than ones located in shallower water. As the little grebe forages preferentially in shallow waters, these results suggest that optimal nesting locations may be the result of a trade-off between conflicting selection pressures such as foraging efficiency (better in shallow waters) and nest predation risk (greater in shallow waters).

Discussion on the cultivation method of the postgraduate students in geriatrics

Since China enters the aging society, there are several apparent trends, such as large elderly population base, rapid growth, aging, dysfunctional and empty nest. These phenomenon leads to a huge economic and social burden for our country and individuals. To meet the health demand of elderly population, our society urgently needs more professional and more comprehensive geriatricians. However, the current education methods, to some extent, limit the possibility of the graduates becoming a good geriatric medicine physician in relatively short period. Therefore, it is necessary to reform the geriatrics education methods. Systematic learning method, mutual complementarily method and Problem-based Learning (PBL) method can be used to help geriatrics graduate students master the theoretical knowledge and practical skills before working and lay a solid founding for becoming a good geriatric medicine physician in relatively short period. Key words: Geriatrics; Graduate education; Systematic learning method; Mutual complementarily method; Problem-based learning

A survey of macroinvertebrates colonizing bluehead chub nests in a Virginia stream

Chubs of the genus Nocomis build large pebble nests that may serve as an important microhabitat for macroinvertebrates and small vertebrates in streams of eastern North America. Macroinvertebrates that use chub nests have not been systematically documented. In this study, we examined the macroinvertebrate communities present inside bluehead chub Nocomis leptocephalus nests in a small tributary creek of the New River in Virginia, USA. Individuals from 38 families of macroinvertebrates were recovered from nests. Snails from the family Pleuroceridae were the most numerous invertebrates in four nests examined, making up an average of 13.6 ± 7.53% of the macroinvertebrate community. This study revealed that communities in chub nests are diverse but not necessarily unique from the surrounding stream substrate. More long-term studies on macroinvertebrate communities of chub nests are needed to elucidate the function of nests as a stream microhabitat.

Experimental enlargement of nest size does not increase risk of predation or brood parasitism in the Great Reed Warbler Acrocephalus arundinaceus

We assessed whether nest size affects the probability of nest loss using dyads of large and small (large being twice the size of small) inactive Great Reed Warbler Acrocephalus arundinaceus nests placed at similar sites in Great Reed Warbler territories. Large nests were not predated significantly more frequently than small nests. Experimentally enlarged active Great Reed Warbler nests suffered non‐significantly higher predation compared with non‐manipulated control nests. Our experiments did not support the nest‐size hypothesis and suggested that nest size does not appear to be a factor affecting the risk of nest predation in this species. The probability of brood parasitism by the Common Cuckoo Cuculus canorus was also unaffected by experimental nest enlargement, supporting the commonly accepted hypothesis that the Common Cuckoo searches for suitable host nests by host activity during nest building rather than nest size.

Reciprocal protection from natural enemies in an ant-wasp association

We show that in French Guiana the large carton nests of Azteca chartifex, a territorially-dominant arboreal dolichoderine ant, are protected from bird attacks when this ant lives in association with Polybia rejecta, an epiponine social wasp. Because A. chartifex colonies are well known for their ability to divert army ant raids from the base of their host tree so that they protect their associated wasps from these raids, there is a reciprocal benefit for these two partners, permitting us to call this association a mutualism. We also show that P. rejecta nests are significantly less often attacked by birds than are those of two compared epiponine social wasp species. Furthermore, experimentation using a standardized protocol demonstrated the significantly higher aggressiveness of P. rejecta compared to seven other wasp species. We conclude that the efficacious protection of its associated ant nests is likely due to the extreme aggressiveness of P. rejecta.

Description of the nest, eggs, and nestling of Rufous-bellied Bush-Tyrants (Myiotheretes fuscorufus)

The Myiotheretes bush-tyrants are a small clade of Neotropical flycatchers (family: Tyrannidae) localized to narrow elevational strips in the Andes Mountains. Here, we describe the first reported nest of Rufous-bellied Bush-Tyrants (Myiotheretes fuscorufus). It was a large cup nest lined with Usnea lichen and elevated on a sheltered rock ledge behind a flowering Puya bromeliad at 2,985 m asl in the buffer zone of Manu National Park, Peru. We provide a near-complete history of the nest from eggs through fledging, and compare data with previous nesting reports for other Myiotheretes species.

Spatially Heterogeneous Nest-Clearing Behavior Coincides with Rain Event in the Leaf-Cutting Ant Atta cephalotes (L.) (Hymenoptera: Formicidae).

Leaf-cutting ants of the genus Atta construct the probably largest nests among ants and are ecosystem engineers because they alter light and nutrient availability at nest sites. Besides creating canopy gaps in the forest, workers remove all vegetation from atop their nest mounds. Here, we examined the extent and spatial distribution of this nest-clearing behavior by transplanting Licania tomentosa seedlings on Atta cephalotes (Linnaeus) nest mounds in the Atlantic forest in northeast Brazil and documented defoliation patterns by the workers. Within 9 days, workers removed around 53% of the total leaf area planted per colony. All colonies showed a synchronized start of defoliation after a rain event in the fifth night after the seedlings had been transplanted. Defoliation increased with time elapsed since transplanting and with the number of entrances surrounding each seedling. In addition, workers started defoliation on the top of the mound. In contrast, the distance to the next entrance and the size of the seedling did not affect the defoliation pattern. Defoliation was not part of the colony foraging activities but was identified as an element of nest maintenance. Possible cues triggering nest-clearing behavior and the potential link between nest-clearing activities and the control of microclimate of ant nests are discussed.

Loess and bee-eaters III: Birds and ground in the Punjab and the Indus region

Part 3 of the study of loess ground and bee-eater birds concerns birds and ground in the north-western part of the Indian Sub-continent. Three species of bee-eaters are considered, relative to the Indus region: the Green bee-eater, the Blue-cheeked bee-eater and the European bee-eater. Loess in the Indus region is considered via the deterministic approach to loess deposit formation; the P events occur in the mountains of the western part of High Asia, particles are formed by the action of mountain glaciers. Major T actions involve the five rivers of the region which carry loess material into the Punjab plains. Subsequent T actions deliver loess material to local deposits, which provide nesting grounds for bee-eaters. To some extent the bee-eaters define the loess. The Green bee-eater is small (16–18 cm long) and lives over all of India and Pakistan-nesting ground is available everywhere. The larger bee-eaters (European and Blue-cheeked: (25 cm)) are more constrained by ground properties-they require the ideal properties of loess ground (an ideal positioning relative to the Heneberg compromise) for nesting, and thus tend to define loess extent. Soil mechanics requires that more exact stress conditions are achieved when a relatively large nest tunnel is being constructed.

Modulated Tool Path (MTP) Machining for Threading Applications

The modulated tool path (MTP) chip breaking process has been modified to improve chip management capabilities and to prevent large chip nest accumulations commonly encountered in threading operations. The use of MTP to create segmented chips requires a different approach for threading operations than for normal MTP turning operations, although the fundamental principal is the same. The primary difference between MTP for threading and for straight turning is that the part surface that the tool repeatedly engages and disengages, during the modulation process, is the thread root rather than the cut face. The threading MTP part program developed in this paper is capable of machining a thread with the desired lead, depth, undercut angle, and taper angle while also producing segmented chips.