Influence of Abiotic Factors and Floral Resource Availability on Daily Foraging Activity of Bees

In this study, the daily and seasonal influences of abiotic factors and the amount of floral resources on the foraging frequency of bees were determined. The experiments were performed, during 12 consecutive months, in the main floral sources used by bees in a secondary forest fragment. The foraging frequency of each bee species on flowers of each plant was recorded for 20-min periods, every hour. To verify whether the foraging activity is influenced by abiotic factors, Pearson's correlation analysis and linear regression tests were performed for the dominant bee species. Temperature and luminosity were the two main abiotic factors regulating foraging activities of bees. A positive correlation was found between the foraging frequency of most bees and these two variables. Conversely, the foraging activity was influenced neither by the relative humidity nor by the wind speed. The activity of each species depends on a combination of factors that include not only abiotic variables, but also the amount of floral resources available during the day, body size, and behavior of each visitor. After a certain period of the day, the scarcity of floral resources produced by most plants can stimulate the bees to forage in the flowers early in subsequent days, which may occur before the period in which the abiotic conditions are really favorable.

Foraging Activity and Seasonal Food Preference of Linepithema micans (Hymenoptera: Formicidae), a Species Associated With the Spread of Eurhizococcus brasiliensis (Hemiptera: Margarodidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluation of growth and foraging in laboratory colonies of Coptotermes gestroi (Isoptera, Rhinotermitidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Congruent spatial and temporal foraging by a dominant ant (Hym., Formicidae) and its replacement in an assemblage in a large urban structure in southeastern Brazil

At fixed bail stations in a large institutional setting in Brazil, the temporal and spatial pattern of usage of the dominant species of ant was studied. The ant Crematogaster cf. magnifica, was found in 91% of sampling points. These studies were conducted using the same points as a previous study of tile then dominant ant. Monomorium pharaonis, which was found to have declined from 93% to 3% spatial point occupation. The frequency of point usage during this study was significantly different from the Poisson distribution for both species, indicating non-random use of space. Crematogaster cf. magnifica was significantly more spatially exclusive than had been documented for M. pharaonis, and the probability of points originally occupied by M. pharaonis later becoming occupied by C. cf. magnifica was in excess of 90%. Temporal bait exploitation patterns of the two species did not differ. These data demonstrate that structural ant communities can change over time without human intervention, although short- term stability is characteristic of the urban dominant ants in subtropical Brazil.

Dynamics of foraging trails in the Neotropical termite Velocitermes heteropterus (Isoptera: Termitidae)

Foraging behavior in termites varies with the feeding habits of each species but often occurs through the formation of well-defined trails that connect the nest to food sources in species that build structured nests. We studied the formation of foraging trails and the change in caste ratio during foraging in the termite Velocitermes heteropterus. This species is widespread in Cerrado vegetation where it builds epigeal nests and forages in open-air at night. Our aim was to understand the processes involved in the formation of foraging trails, from the exploration of new unmarked areas to the recruitment of individuals to food and the stabilization of traffic on the trails, as well as the participation of the different castes during these processes. Foraging trails were videotaped in the laboratory and the videos were then analyzed both manually and automatically to assess the flow of individuals and the caste ratio on the trails as well as to examine the spatial organization of traffic over time. Foraging trails were composed of minor workers, major workers, and soldiers. The flow of individuals on the trails gradually increased from the beginning of the exploration of new areas up to the discovery of the food. The caste ratio remained constant throughout the foraging excursion: major workers, minor workers and soldiers forage in a ratio of 8:1:1, respectively. The speed of individuals was significantly different among castes, with major workers and soldiers being significantly faster than minor workers. Overall, our results show that foraging excursions in V. heteropterus may be divided in three different phases, characterized by individual speeds, differential flows and lane segregation.

Diet overlap and foraging activity between feral pigs and native peccaries in the pantanal

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Use of chemical tracers in assessing the diet and foraging regions of eastern North Pacific killer whales

Top predators in the marine environment integrate chemical signals acquired from their prey that reflect both the species consumed and the regions from which the prey were taken. These chemical tracers—stable isotope ratios of carbon and nitrogen; persistent organic pollutant (POP) concentrations, patterns and ratios; and fatty acid profiles—were measured in blubber biopsy samples from North Pacific killer whales (Orcinus orca) (n = 84) and were used to provide further insight into their diet, particularly for the offshore group, about which little dietary information is available. The offshore killer whales were shown to consume prey species that were distinctly different from those of sympatric resident and transient killer whales. In addition, it was confirmed that the offshores forage as far south as California. Thus, these results provide evidence that the offshores belong to a third killer whale ecotype. Resident killer whale populations showed a gradient in stable isotope profiles from west (central Aleutians) to east (Gulf of Alaska) that, in part, can be attributed to a shift from off-shelf to continental shelf-based prey. Finally, stable isotope ratio results, supported by field observations, showed that the diet in spring and summer of eastern Aleutian Island transient killer whales is apparently not composed exclusively of Steller sea lions.

Use of chemical tracers in assessing the diet and foraging regions of eastern North Pacific killer whales

Top predators in the marine environment integrate chemical signals acquired from their prey that reflect both the species consumed and the regions from which the prey were taken. These chemical tracers—stable isotope ratios of carbon and nitrogen; persistent organic pollutant (POP) concentrations, patterns and ratios; and fatty acid profiles—were measured in blubber biopsy samples from North Pacific killer whales (Orcinus orca) (n = 84) and were used to provide further insight into their diet, particularly for the offshore group, about which little dietary information is available. The offshore killer whales were shown to consume prey species that were distinctly different from those of sympatric resident and transient killer whales. In addition, it was confirmed that the offshores forage as far south as California. Thus, these results provide evidence that the offshores belong to a third killer whale ecotype. Resident killer whale populations showed a gradient in stable isotope profiles from west (central Aleutians) to east (Gulf of Alaska) that, in part, can be attributed to a shift from off-shelf to continental shelf-based prey. Finally, stable isotope ratio results, supported by field observations, showed that the diet in spring and summer of eastern Aleutian Island transient killer whales is apparently not composed exclusively of Steller sea lions.

Selective Foraging For Anthropogenic Resources By Black Bears: Minivans In Yosemite National Park

Black bears (Ursus americanus) forage selectively in natural environments. To determine if bears also forage selectively for anthropogenic resources we analyzed data on vehicles broken into by bears from Yosemite National Park, California. We classified vehicles into 9 categories based on their make and model and collected data on use (2001–2007) and availability (2004–2005). From 2001 to 2007 bears broke into 908 vehicles at the following rates: minivan (26.0%), sport–utility vehicle (22.5%), small car (17.1%), sedan (13.7%), truck (11.9%), van (4.2%), sports car (1.7%), coupe (1.7%), and station wagon (1.4%). Only use of minivans (29%) during 2004–2005 was significantly higher than expected (7%). We discuss several competing hypotheses about why bears selected minivans.

The Effects of Ornamentation on Wolf Spider Foraging

ABSTRACT: As a secondary sexual trait that can increase reproductive success, ornamentation is believed to be costly for organisms to acquire and possess. This study investigates possible costs of ornamentation on wolf spider foraging by comparing foraging abilities of two male forms that differ in ornamentation upon maturation. The two male forms, found syntopically in a mixed population in Mississippi, USA, resemble two sibling species: Schizocosa ocreata, in which males develop large black brushes on their forelegs upon maturation, and Schizocosa rovneri, in which males lack ornamentation following maturation. Individuals of both forms participated in foraging trials as penultimates (juveniles) and as matures. Analyses were conducted to compare behaviors and determine changes in foraging abilities between male forms (non-ornamented vs. brush-legged) and between age groups (penultimate vs. mature). Most foraging behaviors of the two male forms during immaturity were similar with the exception that brush-legged males attacked more frequently than non-ornamented males. Brush-legged males attacked less, spent more time moving, and improved capture abilities as matures, while non-ornamented males retained similar trends for these behaviors with age. Additionally, while capture abilities improved with age among brush-legged males, killing abilities remained constant. This disparity was due to increased escapes made by captured prey items, possibly due to hindrances caused by brush presence preventing secure holds onto crickets. In summary, differences in foraging exist between brush-legged and non-ornamented males prior to sexual maturation, and the development of/presence of brushes appears to influence adult male foraging efficiency.

Extremely slow feeding in a tropical drilling ectoparasite, Vitularia salebrosa (King and Broderip, 1832) (Gastropoda: Muricidae), on molluscan hosts from Pacific Panama

This study documents one of the slowest feeding behaviors ever recorded for a muricid gastropod in one of the most biotically rigorous regions on the planet. In Pacific Panama, Vitularia salebrosa attacks mollusks by drilling through their shells. The duration of attacks estimated by isotope sclerochronology of oyster shells collected during attacks in progress range from 90 to 230 days, while experimental observation of interactions documented one attack greater than 103 days. The prolonged nature of attacks suggests that V. salebrosa is best characterized as an ectoparasite than as a predator, which is the ancestral condition in the Muricidae. An ectoparasitic lifestyle is also evident in the unusual interaction traces of this species, which include foot scars, feeding tunnels and feeding tubes, specialized soft anatomy, and in the formation of male-female Pairs, which is consistent with protandrous hermaphroditism, as is typical in sedentary gastropods. To delay death of its host, V. salebrosa targets renewable resources when feeding, such as blood and digestive glands. A congener, Vitularia miliaris from the Indo-Pacific, has an identical feeding biology The origin and persistence of extremely slow feeding in the tropics challenges our present understanding of selective pressures influencing the evolution of muricid feeding behaviors and morphological adaptations. Previously, it has been suggested that faster feeding is advantageous because it permits predators to spend a greater proportion of time hiding in enemy-free refugia or to take additional prey, the energetic benefits of which could be translated into increased fecundity or defenses. The benefits of exceptionally slow feeding have received little consideration. In the microhabitat preferred by V. salebrosa (beneath boulders), it is possible that prolonged interactions with hosts decrease vulnerability to enemies by reducing the frequency of risky foraging events between feedings . Ectoparasitic feeding through tunnels by V. salebrosa may also reduce competitive interactions with kleptoparasites (e.g., crabs, snails) that steal food through the gaped valves of dead or dying hosts.

Paternal Care Decreases Foraging Activity and Body Condition, but Does Not Impose Survival Costs to Caring Males in a Neotropical Arachnid

Exclusive paternal care is the rarest form of parental investment in nature and theory predicts that the maintenance of this behavior depends on the balance between costs and benefits to males. Our goal was to assess costs of paternal care in the harvestman Iporangaia pustulosa, for which the benefits of this behavior in terms of egg survival have already been demonstrated. We evaluated energetic costs and mortality risks associated to paternal egg-guarding in the field. We quantified foraging activity of males and estimated how their body condition is influenced by the duration of the caring period. Additionally, we conducted a one-year capture-mark-recapture study and estimated apparent survival probabilities of caring and non-caring males to assess potential survival costs of paternal care. Our results indicate that caring males forage less frequently than non-caring individuals (males and females) and that their body condition deteriorates over the course of the caring period. Thus, males willing to guard eggs may provide to females a fitness-enhancing gift of cost-free care of their offspring. Caring males, however, did not show lower survival probabilities when compared to both non-caring males and females. Reduction in mortality risks as a result of remaining stationary, combined with the benefits of improving egg survival, may have played an important and previously unsuspected role favoring the evolution of paternal care. Moreover, males exhibiting paternal care could also provide an honest signal of their quality as offspring defenders, and thus female preference for caring males could be responsible for maintaining the trait.

Carlosbarbosaite, ideally (UO2)(2)Nb2O6(OH)(2)center dot 2H(2)O, a new hydrated uranyl niobate mineral with tunnels from Jaguaracu, Minas Gerais, Brazil: description and crystal structure

Carlosbarbosaite, ideally (UO2)(2)Nb2O6(OH)(2)center dot 2H(2)O, is a new mineral which occurs as a late cavity filling in albite in the Jaguaracu pegmatite, Jaguaracu municipality, Minas Gerais, Brazil. The name honours Carlos do Prado Barbosa (1917-2003). Carlosbarbosaite forms long flattened lath-like crystals with a very simple orthorhombic morphology. The crystals are elongated along [001] and flattened on (100); they are up to 120 mu m long and 2-5 mu m thick. The colour is cream to pale yellow, the streak yellowish white and the lustre vitreous. The mineral is transparent (as individual crystals) to translucent (massive). It is not fluorescent under either long-wave or short-wave ultraviolet radiation. Carlosbarbosaite is biaxial(+) with alpha = 1.760(5), beta = 1.775(5), gamma = 1.795(5), 2V(meas) = 70(1)degrees, 2V(calc) = 83 degrees. The orientation is X parallel to a, Y parallel to b, Z parallel to c. Pleochroism is weak, in yellowish green shades, which are most intense in the Z direction. Two samples were analysed. For sample I, the composition is: UO3 54.52, CaO 2.07, Ce2O3 0.33, Nd2O3 0.49, Nb2O5 14.11, Ta2O5 15.25, TiO2 2.20, SiO2 2.14, Fe2O3 1.08, Al2O3 0.73, H2O (calc.) 11.49, total 104.41 wt.%; the empirical formula is (square 0.68Ca0.28Nd0.02Ce0.02)(Sigma=1.00)[U-1.44 square O-0.56(2.88)(H2O)(1.12)](Nb0.80Ta0.52Si0.27Ti0.21Al0.11Fe0.10)(Sigma=2.01) O-4.72(OH)(3.20)(H2O)(2.08). For sample 2, the composition is: UO3 41.83, CaO 2.10, Ce2O3 0.31, Nd2O3 1.12, Nb2O5 14.64, Ta2O5 16.34, TiO2 0.95, SiO2 3.55, Fe2O3 0.89, Al2O3 0.71, H2O (calc.) 14.99, total 97.43 wt.%; the empirical formula is (square 0.67Ca0.27Nd0.05Ce0.01)(Sigma=1.00)[U-1.04 square O-0.96(2.08)(H2O)(1.92)] (Nb0.79Ta0.53Si0.42Ti0.08Al0.10Fe0.08)(Sigma=2.00)O-4.00(OH)(3.96)(H2O)(2.04). The ideal endmember formula is (UO2)(2)Nb2O6(OH)(2)center dot 2H(2)O. Calculated densities are 4.713 g cm(-3) (sample 1) and 4.172 g cm(-3) (sample 2). Infrared spectra show that both (OH) and H2O are present. The strongest eight X-ray powder-diffraction lines [listed as d in angstrom(I)(hkl)] are: 8.405(8)(110), 7.081(10)(200), 4.201(9)(220), 3.333(6)(202), 3.053(8)(022), 2.931(7)(420), 2.803(6)(222) and 2.589(5)(040,402). The crystal structure was solved using single-crystal X-ray diffraction (R = 0.037) which gave the following data: orthorhombic, Cmem, a = 14.150(6), b = 10.395(4), c = 7.529(3) angstrom, V = 1107(1) angstrom(3), Z = 4. The crystal structure contains a single U site with an appreciable deficiency in electron scattering, which is populated by U atoms and vacancies. The U site is surrounded by seven 0 atoms in a pentagonal bipyramidal arrangemet. The Nb site is coordinated by four 0 atoms and two OH groups in an octahedral arrangement. The half-occupied tunnel Ca site is coordinated by four 0 atoms and four H2O groups. Octahedrally coordinated Nb polyhedra share edges and comers to form Nb2O6(OH)(2) double chains, and edge-sharing pentagonal bipyramidal U polyhedra form UO5 chains. The Nb2O6(OH)(2) and UO5 chains share edges to form an open U-Nb-phi framework with tunnels along [001] that contain Ca(H2O)(4) clusters. Carlosbarbosaite is closely related to a family of synthetic U-Nb-O framework tunnel structures, it differs in that is has an (OH)-bearing framework and Ca(H2O)(4) tunnel occupant. The structure of carlosbarbosaite resembles that of holfertite.

Sodium-specific foraging by leafcutter ant workers (Atta cephalotes, Hymenoptera: Formicidae)

1. Sodium is often a limiting nutrient for terrestrial animals, and may be especially sought by herbivores. Leafcutter ants are dominant herbivores in the Neotropics, and leafcutter foraging may be affected by nutritional demands of the colony and/or the demands of their symbiotic fungal mutualists. We hypothesized that leafcutter colonies are sodium limited, and that leafcutter ants will therefore forage specifically for sodium. 2. Previous studies demonstrated that leafcutter Atta cephalotes Linnaeus workers preferentially cut and remove paper baits treated with NaCl relative to water control baits. Atta cephalotes colonies in this study were presented with baits offering NaCl, Na2SO4, and KCl to test whether leafcutters forage specifically for sodium. Sucrose and water were used as positive and negative controls, respectively. 3. Atta foragers removed significantly more of the baits treated with NaCl and Na2SO4 than the KCl treatment, which did not differ from water. The NaCl and Na2SO4 treatments were collected at similar rates. We conclude A. cephalotes forage specifically for sodium rather than for anions (chloride) or solutes in general. This study supports the hypothesis that leafcutter ants are limited by, and preferentially forage for, sodium.