Synopsis
Despite considerable research on lek-breeding birds, many aspects of the evolution of the lek social system, including the origin of male aggregation, remain unresolved. Originally, clusters ...may have formed passively as a by-product of independent but concurrent responses by males to some external stimulus (e.g., a concentration of display sites, prominent food source, or a travel corridor commonly used by females) that drew them at a particular time to a site where they might increase their probabilities of encountering females. In contrast, male aggregation may have been active, with a male purposely seeking to associate with another male (or males) because proximity to that male allowed him to enhance his own reproductive success by improving his ability to attract females (i.e., learning from his associate) or to intercept females attracted to that male. To identify factors important in the formation of male aggregations, I studied these alternatives in the Dwarf Tyrant-Manakin (Tyranneutes stolzmanni), a species in which some breeding males occupy solitary courts where they attempt to attract females for reproduction, whereas other males occupy courts clustered into leks, where they interact to attract females. I compared habitat characteristics and resource availability at courts of grouped and solitary males as well as certain traits of the males in an attempt to distinguish between passive or active lek formation in this species. Little evidence suggests that Dwarf Tyrant-Manakins are passively clustered as a result of common attraction to or use of a limited or unevenly distributed resource. Several observations suggest the contrary. Evidence for the active aggregation of males is more promising, suggesting that males may associate with other males on the basis of their vocal behavior. The issue is confounded, however, by the observation that male call behavior appears to change with a change in social status. A definitive answer for T. stolzmanni will require additional analyses of vocal behavior as well as of the characteristics of the vocalizations themselves. Finally, the behavior and social organization of this species may reflect characteristics of the ancestral manakin line that gave rise to both the Tyrant and Core clades of modern manakins.
From tiny, burrowing lizards to rainforest canopy-dwellers and giant crocodiles, reptile populations everywhere are changing. Yet government and conservation groups are often forced to make important ...decisions about reptile conservation and management based on inadequate or incomplete data. With contributions from nearly seventy specialists, this volume offers a comprehensive guide to the best methods for carrying out standardized quantitative and qualitative surveys of reptiles, while maximizing comparability of data between sites, across habitats and taxa, and over time. The contributors discuss each method, provide detailed protocols for its implementation, and suggest ways to analyze the data, making this volume an essential resource for monitoring and inventorying reptile abundance, population status, and biodiversity. Reptile Biodiversity covers topics including: • terrestrial, marine, and aquatic reptiles • equipment recommendations and limitations • ethics of monitoring and inventory activities • statistical procedures • designing sampling programs • using PDAs in the field
Biodiversity of Fungi Mueller, Greg M; Foster, Mercedes S; Bills, Gerald F
2004, 2004-12-31
eBook
Biodiversity of Fungi is essential for anyone collecting and/or monitoring any fungi. Fascinating and beautiful, fungi are vital components of nearly all ecosystems and impact human health and our ...economy in a myriad of ways. Standardized methods for documenting diversity and distribution have been lacking. A wealth of information, especially regrading sampling protocols, compiled by an international team of fungal biologists, make Biodiversity of Fungi an incredible and fundamental resource for the study of organismal biodiversity. Chapters cover everything from what is a fungus, to maintaining and organizing a permanent study collection with associated databases; from protocols for sampling slime molds to insect associated fungi; from fungi growing on and in animals and plants to mushrooms and truffles. The chapters are arranged both ecologically and by sampling method rather than by taxonomic group for ease of use. The information presented here is intended for everyone interested in fungi, anyone who needs tools to study them in nature including naturalists, land managers, ecologists, mycologists, and even citizen scientists and sophiscated amateurs. Covers all groups of fungi - from molds to mushrooms, even slime molds Describes sampling protocols for many groups of fungi Arranged by sampling method and ecology to coincide with users needs Beautifully illustrated to document the range of fungi treated and techniques discussed Natural history data are provided for each group of fungi to enable users to modify suggested protocols to meet their needs.
Calcium is an important nutrient for birds, especially for eggshell production and the mineralization of the skeleton of developing young. In temperate regions insects and seeds that form the bulk of ...the diet of breeding passerines do not contain sufficient calcium to meet the needs of breeding females and young; these birds obtain their calcium by eating snails, woodlice and millipedes. Little is known about the way tropical frugivorous passerines meet their calcium needs. The calcium contents of fruits of 34 species eaten by birds during the breeding season in mature floodplain forest in south-eastern Peru were determined. The suitability of these fruits as calcium sources for hypothetical 10-g and 25-g birds and for 26 species of frugivore that breed at the study site was evaluated based on bird body weight and on the rictal width of the bill, which influences feeding. Fruits of five species in the study area appear to be suitable sources of calcium for birds ≤25 g, although those of Ficus killipii (Moraceae) are likely optimal. The latter contain a lot of calcium (2.48% dry weight of pulp or c. 4.15 mg per pulp per fruit) and are small enough (mean diam. = 9 mm) for most birds to swallow whole, and trees produce large crops. Snails, woodlice and millipedes are common in the area and also contain sufficient calcium to meet birds’ needs. In addition, birds could likely meet their calcium needs through geophagy at natural mineral licks.
The relative effectiveness of arboreal or terrestrial birds at dispersing seeds of Ormosia macrocalyx and O. bopiensis (Fabaceae: Papilionoideae) were studied in south-eastern Peru. Seeds of both ...species were either scarified, to represent seed condition after dispersal by terrestrial birds, or left intact, to represent seed condition after dispersal by arboreal birds. Seeds were distributed along forest transects, and germination, seedling development and mortality were monitored to determine the successes of the two groups at producing seedlings. Scarified seeds germinated with the early rains of the dry-to-wet-season transition, when erratic rainfall was interspersed with long dry spells. Intact seeds germinated 30 d later when the rain was more plentiful and regular. Intact seeds of O. macrocalyx gave rise to significantly more seedlings (41.1% vs. 25.5%) than did scarified seeds, in part, because significantly more seedlings from scarified seeds (n = 20) than from intact seeds (n = 3) died from desiccation when their radicles failed to enter the dry ground present during the dry-to-wet-season transition. Also, seedlings from scarified seeds were neither larger nor more robust than those from intact seeds despite their longer growing period. Results are consistent with the hypothesis that dispersal effectiveness of arboreal birds, at least for O. macrocalyx, is greater than that of terrestrial birds. Screen-house experiments in which seedlings developed under different watering regimes supported this result. Numbers of seedlings developing from intact and scarified seeds of O. bopiensis did not differ significantly.
Functional dysregulation of the glutamate system during withdrawal from chronic drug exposure is a primary driver of drug craving and relapse. Animal models of psychostimulant use have demonstrated ...dynamic alterations in NMDA receptor function and expression that contribute to drug seeking behavior. These changes begin as early as 5 days following cessation of drug use are persistently expressed into long term withdrawal (>60d). Evidence of NMDA receptor dependent changes during short term withdrawal (24h) suggest that similar mechanisms may drive drug craving and relapse behaviors following chronic exposure to ethanol. To this end, we investigated NMDA receptor protein and surface expression during protracted withdrawal from chronic intermittent ethanol (CIE) exposure using western blot. We focused on the basolateral amygdala (BLA), as glutamatergic signaling in this region is robustly modulated by short term (24h) withdrawal from CIE (10d, 12hr/day) and regulates anxiety‐like behavior expressed during withdrawal. Adolescent male rats were exposed to repeated cycles of CIE (12hr/day, 4d on/3d off, 3 cycles) and brain tissue was collected during protracted withdrawal. Optimization of experimental procedures is currently being conducted and analysis of total and membrane surface expression will be analyzed by surface biotinylation for NMDAR subunits (GluN1, GluN2B, GluN3). Cell surface biotinylation will be used to isolate cell surface membrane proteins to detect and quantify expression of NMDAR subunits. We expect to identify an increase in membrane surface expression for NMDAR subunits, in agreement with functional data obtained in the laboratory.
The choice of fruits by an avian frugivore is affected by choices it makes at multiple hierarchical levels (e.g., species of fruit, individual tree, individual fruit). Factors that influence those ...choices vary among levels in the hierarchy and include characteristics of the environment, the tree, and the fruit itself. Feeding experiments with wild-caught birds were conducted at El Tirol, Departamento de Itapúa, Paraguay to test whether birds were selecting among individual fruits based on fruit size. Feeding on larger fruits, which have proportionally more pulp, is generally more efficient than feeding on small fruits. In trials (n = 56) with seven species of birds in four families, birds selected larger fruits 86% of the time. However, in only six instances were size differences significant, which is likely a reflection of small sample sizes.
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Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Lek-mating Long-tailed Manakins (Chiroxiphia linearis) exhibit an unusual pattern of delayed plumage maturation. Each year, males progress through a series of predefinitive plumages before attaining ...definitive plumage in their fifth calendar year. Females also exhibit variation in plumage coloration, with some females displaying male-like plumage characteristics. Using data from mist-net captures in northwest Costa Rica (n = 1,315) and museum specimens from throughout the range of Long-tailed Manakins (n = 585), we documented the plumage sequence progression of males, explored variation in female plumage, and described the timing of molt in this species. Males progressed through a series of age-specific predefinitive plumages, which enabled the accurate aging of predefinitive-plumaged males in the field; this predefinitive plumage sequence is the basis for age-related status-signaling in these males. Females tended to acquire red coloration in the crown as they aged. However, colorful plumage in females may be a byproduct of selection on bright male plumage. Females exhibited an early peak of molt activity from February to April, little molt from May through July, and a second, more pronounced peak of molt activity in October. By contrast, males in older predefinitive-plumage stages and males in definitive plumage exhibited comparable unimodal distributions in molt activity beginning in June and peaking between July and October. Our data are consistent with selective pressure to avoid the costs of molt-breeding overlap in females and older males. Our findings have important implications for social organization and signaling in Long- tailed Manakins, and for the evolution of delayed plumage maturation in birds. Desarrollo del Plumaje y Muda en Chiroxiphia linearis: Variación de Acuerdo al Sexo y la Edad
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Reptile Biodiversity Dr. Roy W. McDiarmid, Dr. Mercedes S. Foster, Dr. Craig Guyer, Dr. J. Whitfield Gibbons, Dr. Neil Chernoff / Dr. Roy W. McDiarmid, Dr. Mercedes S. Foster, Dr. Craig Guyer, Dr. J. Whitfield Gibbons, Dr. Neil Chernoff
2012
eBook
From tiny, burrowing lizards to rainforest canopy-dwellers and giant crocodiles, reptile populations everywhere are changing. Yet government and conservation groups are often forced to make important ...decisions about reptile conservation and management based on inadequate or incomplete data. With contributions from nearly seventy specialists, this volume offers a comprehensive guide to the best methods for carrying out standardized quantitative and qualitative surveys of reptiles, while maximizing comparability of data between sites, across habitats and taxa, and over time. The contributors discuss each method, provide detailed protocols for its implementation, and suggest ways to analyze the data, making this volume an essential resource for monitoring and inventorying reptile abundance, population status, and biodiversity. Reptile Biodiversity covers topics including: • terrestrial, marine, and aquatic reptiles • equipment recommendations and limitations • ethics of monitoring and inventory activities • statistical procedures • designing sampling programs • using PDAs in the field
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