Behavioral transitions with the evolution of cooperative nest founding by harvester ant queens

Research on the evolution of cooperative groups tends to explore the costs and benefits of cooperation, with less focus on the proximate behavioral changes necessary for the transition from solitary to cooperative living. However, understanding what proximate changes must occur, as well as those pre-conditions already in place, is critical to understanding the origins and evolution of sociality. The California harvester ant Pogonomyrmex californicus demonstrates population-level variation in colony founding over a close geographic range. In adjacent populations, queens either found nests as single individuals (haplometrosis) or form cooperative groups of nonrelatives (pleometrosis). We compared aggregation, aggression, and tolerance of queens from one pleometrotic and two haplometrotic populations during nest initiation, to determine which behaviors show an evolutionary shift and which are present at the transition to pleometrosis. Surprisingly, within-nest aggregative behavior was equally present among all populations. In nesting boxes with multiple available brood-rearing sites, both queen types readily formed and clustered around a single common brood pile, suggesting that innate attraction to brood (offspring) facilitates the transition to social aggregation. In contrast, queens from the three populations differed in their probabilities of attraction on the ground to nest sites occupied by other queens and in levels of aggression. Our results suggest that some key behavioral mechanisms facilitating cooperation in P. californicus are in place prior to the evolution of pleometrosis and that the switch from aggression to tolerance is critical for the evolution of stable cooperative associations.     

Chemical oxidation using stabilized hydrogen peroxide in high temperature,saline groundwater impacted with hydrocarbons and MTBE

In situ chemical oxidation (ISCO) of petroleum hydrocarbons (PHCs) within groundwater is considered a proven approach to addressing PHC‐impacted groundwater in nonsaline environments. One of the most common oxidants used for oxidation of PHCs in groundwater is hydrogen peroxide (H₂O₂). Due to its highly reactive nature, H₂O₂ is often stabilized to aid in increasing its reactivity lifespan. Limited research and application of ISCO has been completed in warm, saline groundwater environments. Furthermore, even fewer studies have been completed in these environments for ISCO using stabilized H₂O₂. In this research, stabilized H₂O₂ was examined to determine its effectiveness in the treatment of PHCs and the additive methyl tert‐butyl ether (MTBE). Three stabilizers (citrate, phytate, silica [SiO₂]) were tested to determine if the stabilizers could enhance and extend the treatment life of H₂O₂ within saline groundwater. To determine the effect of salinity on the three stabilizers, groundwater and aquifer samples were collected from two saline locations that had different salinity (total dissolved solids of about 7,000 mg/L and 18,000 mg/L). Specific target chemicals for treatment were water soluble, mobile components of gasoline including benzene, toluene, ethylbenzene, xylenes, (BTEX) and MTBE. Previous studies using unactivated persulfate indicated that the PHCs within the groundwater could be oxidized, however, only limited oxidation of the MTBE could be affected. The results of the laboratory tests indicated that greater than 95 percent of the target hydrocarbons were removed within 7 days of treatment. Microcosms with citrate‐stabilized H₂O₂ demonstrated a significantly faster and greater decline with most hydrocarbon concentrations reaching < 5 μg/L. The exceptions were ethylbenzene and m‐xylene, which were slightly decreased to about 30 and 20 μg/L, respectively. Initial mean concentrations of the BTEX compounds within the citrate‐stabilized microcosms were 10,554 μg/L, 9,318 μg/L, 6,859 μg/L, and 14,435 μg/L, respectively. The silicate‐stabilized H₂O₂ microcosms showed no significant benefit over the unstabilized control microcosms. The better performance of citrate‐stabilized microcosms was confirmed by increasing δ13C values of remaining hydrocarbons. MTBE declined from > 400 mg/L to < 100 mg/L in all microcosms, again with the best removal (> 90 percent) being measured in the citrate‐stabilized microcosms. Unfortunately, H₂O₂ oxidation in the microcosms also resulted in production of up to 40 mg/L TBA or approximately 10 percent of the MTBE oxidized.     

Differences in sensitivity to the fungal pathogen Batrachochytrium dendrobatidis among amphibian populations

Contributing to the worldwide biodiversity crisis are emerging infectious diseases, which can lead to extirpations and extinctions of hosts. For example, the infectious fungal pathogen Batrachochytrium dendrobatidis (Bd) is associated with worldwide amphibian population declines and extinctions. Sensitivity to Bd varies with species, season, and life stage. However, there is little information on whether sensitivity to Bd differs among populations, which is essential for understanding Bd‐infection dynamics and for formulating conservation strategies. We experimentally investigated intraspecific differences in host sensitivity to Bd across 10 populations of wood frogs (Lithobates sylvaticus) raised from eggs to metamorphosis. We exposed the post‐metamorphic wood frogs to Bd and monitored survival for 30 days under controlled laboratory conditions. Populations differed in overall survival and mortality rate. Infection load also differed among populations but was not correlated with population differences in risk of mortality. Such population‐level variation in sensitivity to Bd may result in reservoir populations that may be a source for the transmission of Bd to other sensitive populations or species. Alternatively, remnant populations that are less sensitive to Bd could serve as sources for recolonization after epidemic events.     

Residence time effects on phase transformation of nanosilver in reduced soils

Residence time effects on phase transformation of silver nanoparticles (AgNPs) (15–50 nm, with and without polyvinylpyrrolidone (PVP) coating) were investigated in reducing soils using experimental geochemistry and synchrotron-based x-ray techniques. After 30 days of anaerobic incubation, a substantial fraction of PVP-coated AgNPs (15 nm) were transformed into Ag₂S and or humic acid (HA) complexed Ag(I), whereas only the HA fraction was dominant in uncoated AgNPs (50 nm). Several investigations recently reported that sulfidation of AgNPs to Ag₂S was the predominant mechanism controlling the fate of AgNP in soil–water environments. However, this investigation showed each AgNP underwent particle-specific chemical transformations to different end compounds after 30 days. Considering the small contribution of Ag(I) dissolution from all AgNPs (less than 5 %), we concluded that changes in solid-state chemical speciation of sorbed AgNPs was promoted by particle-specific interactions of NPs in soil chemical constituents, suggesting a critical role of soil absorbents in predicting the fate of AgNPs in terrestrial environments.     

Full-scale evaluation of mercury control with sorbent injection and COHPAC at Alabama Power E.C. Gaston

The overall objective of this project was to determine the cost and impacts of Hg control using sorbent injection into a Compact Hybrid Particulate Collector (COHPAC) at Alabama Power's Gaston Unit 3. This test is part of a program funded by the U.S. Department of Energy's National Energy Technology Laboratory (NETL) to obtain the necessary information to assess the costs of controlling Hg from coal-fired utility plants that do not have scrubbers for SO2 control. The economics will be developed based on various levels of Hg control. Gaston Unit 3 was chosen for testing because COHPAC represents a cost-effective retrofit option for utilities with existing electrostatic precipitators (ESPs). COHPAC is an EPRI-patented concept that places a high air-to-cloth ratio baghouse downstream of an existing ESP to improve overall particulate collection efficiency. Activated carbons were injected upstream of COHPAC and downstream of the ESP to obtain performance and operational data. Results were very encouraging, with up to 90% removal of Hg for short operating periods using powdered activated carbon (PAC). During the long-term tests, an average Hg removal efficiency of 78% was measured. The PAC injection rate for the long-term tests was chosen to maintain COHPAC cleaning frequency at less than 1.5 pulses/bag/hr.     

Hatching rhythms in Uca pugilator (Decapoda:Brachyura)

Gravid female Uca pugilator (Bosc) maintained in conditions of 14h L: 10h D light regime and constant temperature without simulated tides showed a significant positive correlation between time of hatch and time of the nighttime high tide. Light: Dark experiments showed no entrainment by LD cues. Larval hatching was delayed until dark when high tide occurred between 1900 and 2130 hrs. Hatch time was a positive linear function of the time of the nighttime high tide when high tide occurred after 2130 hrs. Time of hatch was delayed by the light period on days lacking a nighttime high tide. Experiments conducted under constant light (LL) and temperature, without simulated tides, indicated a persistent free-running rhythm of approximately 25 h 03 min, suggesting an endogenous timer. Rhythmic larval release on the nighttime high tide may be adaptive as a predator-avoidance mechanism for adult gravid females.Contribution No. 366 from the Belle W. Baruch Institute for Marine Biology and Coastal Research, University of South Carolina     

The multiphase optimization strategy (MOST) and the sequential multiple assignment randomized trial (SMART): two novel evaluation methods for developing optimal training programs

Current methodologies in training evaluation studies largely employ a single method entitled random confirmatory trials, prompting several concerns. First, practitioners and researchers often analyze the effectiveness of their entire omnibus training, rather than the individual elements or identifiable components of the training program. This slows the testing of theory and development of optimal training programs. Second, a common training is typically administered to all employees within an organization or workgroup; however, certain factors may cause individualized training to be more effective. Given these concerns, the current paper presents two training evaluation methodologies to overcome these problems: the multiphase optimization strategy and sequential multiple assignment randomized trials. The multiphase optimization strategy is a method to evaluate a standard training, which emphasizes the importance of a multi‐stage training evaluation process to analyze individual training elements. In contrast, sequential multiple assignment randomized trial is used to evaluate an adaptive training that varies over time and/or trainees. These methodologies jointly overcome the problems noted earlier, and they can be integrated to address several of the key challenges facing training researchers and practitioners. Copyright © 2016 John Wiley & Sons, Ltd.     

UV wavelengths make female three-spined sticklebacks (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis>) more attractive for males

Numerous fishes possess UV vision and show UV patterns, which often play a role in social communication, especially during courtship. UV light is scattered strongly in water and thus might be used for intra-specific close-range communication without being detected by predators. In addition to the red-belly colouration and blue-coloured iris, male three-spined sticklebacks possess UV reflectance on their skin, and females prefer males presented with UV light rather than without. To investigate whether UV also influences male visual preference for females in this species, we used a dichotomous mate choice design in which one female could be viewed by a male in two visual conditions. Courting male sticklebacks preferred females that were presented in full-spectrum conditions including UV to the same females presented in conditions lacking this light component. Furthermore, control trials with neutral-density filters indicated that male preference in the UV treatment was not affected by a difference in achromatic brightness between the UV+ and UV− stimuli. Reflectance measurements of gravid females suggest an enhanced UV contrast between the dark bar pattern, which is characteristic of gravid females, and silvery body parts.     

Estimation of temporary emigration in male toads

Male boreal toads (Bufo boreas) are thought to return to the breeding site every year but, if absent in a particular year, will be more likely to return the following year. Using Pollock's robust design we estimated temporary emigration (the probability a male toad is absent from a breeding site in a given year) at three locations in Colorado, USA: two in Rocky Mountain National Park and one in Chaffee County. We present data that suggest that not all male toads return to the breeding site every year. Our analyses indicate that temporary emigration varies by site and time (for example, from 1992 to 1998, the probability of temporary emigration ranged from 10% to 29% and from 3% to 95% at Lost Lake and Kettle Tarn, respectively). Although the results provide weak evidence that males are more likely to return after a year's hiatus, a general pattern of state-dependent temporary emigration was not supported. We also hypothesized relationships between temporary emigration and a number of weather variables. While some competitive models included weather covariates, imprecise and variable estimates of the effects of these covariates precluded fully defining their impact on temporary emigration.