Behavior and Functional Ecology of the African Termite-Raiding Ant.

Division of labor is one of the main reasons for the success of social insects. Worker polymorphism, age polyethism and work division in more primitive ants, such as the ponerines, remain mostly unexplored. The group hunting, termite-specialist Megaponera analis conducts raids in column formations of 200–500 ants. Since these ants specialize on a defensive prey, adaptations to reduce their foraging costs can be expected. We found that the work division, task allocation and column formation during the hunt were much more sophisticated than was previously thought. The column-formation was remarkably stable, with the same ants resuming similar positions in subsequent raids and front ants even returning to their positions if displaced in the same raid, suggesting yet unknown regulatory mechanisms for the formation of the column. We identified three previously undescribed tasks during the hunting process of M. analis: lingerers, runners and raid-guards. Most of these tasks were not executed by predetermined members of the raid but were filled out as need arose during the hunt, with a clear preference for larger ants to conduct most tasks. The plasticity of task allocation was particularly well exemplified by the termite carriers, with the number of small ants carrying termites only starting to rise when less large ants were available. We, therefore, propose that the continuous allometric size polymorphism in M. analis allows for greater flexibility in task allocation, necessary due to the unpredictability of task requirements in an irregular system such as hunting termites in groups.

A recurrent question in meta‐analyses is the validity of including both field and laboratory studies in a single analysis, given the differences in characteristics such as the duration or size of these experiments. In particular, are field studies consistently more variable, longer in duration, or do they differ from laboratory studies in other important ways? We examined these questions using an unusually large and comprehensive data set on grazing effects on benthic microalgae, consisting of 865 experiments including both field and lab studies and using marine, lotic or lentic communities of small benthic primary producers. We found there was greater variation in field than laboratory studies, but that this difference explained only 0.5% of the variance in the coefficient of variation. Field studies were longer, on average, than laboratory studies, but experiments in the two systems did not differ consistently in other ecological or design parameters. Thus, the common assumption that field studies have higher variances than laboratory studies, while true, explained only a tiny proportion of the heterogeneity in variation. Therefore, perhaps surprisingly, any conclusions from research syntheses would be unlikely to be affected by consistent differences in variance (or other parameters we examined) between the laboratory and field studies.

Although both laboratory and field studies are needed to effectively assess effects and risk of contaminants to free-living organisms, the limitations of each must be understood. The objectives of this paper are to examine information on field studies of reproductive effects of perfluorinated substances (PFASs) on bird populations, discuss the differences among field studies, and then place those results in context with laboratory studies. Hypotheses to explain the divergences between field studies and between laboratory and field studies will be discussed. Those differences include mixture issues, misattribution of the mechanism or the specific PFAS causing impairments, as well as other possible reasons. Finally, suggestions to better link laboratory and field studies will be presented. Integr Environ Assess Manag 2021;17:690-696. Published 2021. This article is a US Government work and is in the public domain in the USA.

Male–male competition and female mate choice act contemporaneously in the cockroach Nauphoeta cinerea and the social pheromone of males influences the outcome of both forms of sexual selection. We therefore examined the joint and separate effects of male–male competition and female mate choice to determine if the selective optima for the pheromone were the same or different. Dominant males in a newly established hierarchy mated more frequently, but not exclusively. Manipulations of the multi-component social pheromone produced by males of N. cinerea showed that both long- and close-range attraction of females by males were influenced by the quantity and composition of the pheromone. The most attractive composition, however, differed from that which was most likely to confer high status to males. Since the outcome of male–male competition can conflict with mating preferences exhibited by females, there is balancing sexual selection on the social pheromone of N. cinerea. Such balancing selection might act to maintain genetic variation in sexually selected traits. We suggest that the different forms of sexual selection conflict in N. cinerea because females prefer a blend different to that which is most effective in male–male competition in order to avoid mating with overly aggressive males.

Understanding the selective pressures shaping the number of offspring per breeding event is a key area in the study of life-history strategies. However, in species with parental care, costs incurred in offspring production, rather than rearing, have been largely ignored in both theoretical and empirical studies until relatively recently. Furthermore, the few experimental studies that have manipulated production costs have not yet teased apart effects that operate via the parental phenotype from effects on the quality of the resulting young. To examine whether increased egg production influences parental brood rearing capacity independently of effects operating via egg quality, we experimentally increased egg production in gulls and then examined their capacity to rear a control clutch. We found that the capacity of parents to rear the control brood was substantially reduced solely as a consequence of having themselves produced one extra egg. The paradox that, in many species, parents apparently aim for fewer young per breeding event than the experimentally and theoretically demonstrated optimum, has partly arisen from the failure to take into account the constraints imposed by production costs.

Nano and microplastic interactions with freshwater biota – Current knowledge, challenges and future solutions

Nest choice in Temnothorax spp.; task allocation and the regulation of activity in Pheidole dentata, Pogonomyrmex barbatus, and Atta spp.; and trail networks in Monomorium pharaonis and Cephalotes goniodontus all provide examples of correspondences between the dynamics of the environment and the dynamics of collective behavior. Some important aspects of the dynamics of the environment include stability, the threat of rupture or disturbance, the ratio of inflow and outflow of resources or energy, and the distribution of resources. These correspond to the dynamics of collective behavior, including the extent of amplification, how feedback instigates and inhibits activity, and the extent to which the interactions that provide the information to regulate behavior are local or spatially centralized.

The sensitivity of aquatic insects to divalent metals: A comparative analysis of laboratory and field data

Social insects can flexibly respond to variational environment without global information and centralized control, and inspired by the collective behavior in ants and bees, this paper proposes a dynamical response threshold model (DRTM) in which the robots perform task allocation in self-organized manner. The proposed method depends on neither the global information nor the communication between robots. Using this method, the individual robot considers the amount of food in nest as stimulus and can compute the threshold dynamically according to monitoring the number of resting robots as well as counting the times of obstacle avoidance in the last foraging task. Taking advantage of stimulus and threshold, the robots automatically decide whether to forage on the basis of foraging probability. Simulation experiments are carried out with the aim of studying the effectiveness of the proposed model and evaluating the performance of task allocation in foraging scenarios. The experimental results presented in this paper prove that DRTM can achieve an efficient task allocation and possess better self-organized feature compared with the existing fixed response threshold model (FRTM).

Statistical Methods for Field and Laboratory Studies in Behavioral Ecology focuses on how statistical methods may be used to make sense of behavioral ecology and other data. It presents fundamental concepts in statistical inference and intermediate topics such as multiple least squares regression and ANOVA. The objective is to teach students to recognize situations where various statistical methods should be used, understand the strengths and limitations of the methods, and to show how they are implemented in R code. Examples are based on research described in the literature of behavioral ecology, with data sets and analysis code provided. Features: This intermediate to advanced statistical methods text was written with the behavioral ecologist in mind Computer programs are provided, written in the R language. Datasets are also provided, mostly based, at least to some degree, on real studies. Methods and ideas discussed include multiple regression and ANOVA, logistic and Poisson regression, machine learning and model identification, time-to-event modeling, time series and stochastic modeling, game-theoretic modeling, multivariate methods, study design/sample size, and what to do when things go wrong. It is assumed that the reader has already had exposure to statistics through a first introductory course at least, and also has sufficient knowledge of R. However, some introductory material is included to aid the less initiated reader. Scott Pardo, Ph.D., is an accredited professional statistician (PStat®) by the American Statistical Association. Michael Pardo is a Ph.D. is a candidate in behavioral ecology at Cornell University, specializing in animal communication and social behavior.

BackgroundThe efficacy of an extended-release injectable moxidectin (0.5 mg/kg) suspension (ProHeart® 12) (PH 12) in preventing the development of Dirofilaria immitis in dogs for 12 months was investigated in laboratory and field studies in the USA.MethodsIn each of two laboratory studies, 20 dogs ≥ 12 months of age were randomly allocated to receive a subcutaneous injection of saline or PH 12 on Day 0 and were then inoculated with 50 D. immitis third-stage larvae (L3) on Day 365. All dogs were necropsied ~ 5 months post-inoculation for adult worm counts. The field efficacy study included dogs ≥ 10 months of age from 19 veterinary clinics in the USA treated with either 20 monthly doses of Heartgard® Plus (HG Plus) (296 dogs) or two doses of PH 12 (297 dogs) on Days 0 and 365. Efficacy was determined on Days 365, 480 and 605 using adult HW antigen and microfilaria testing to assess adult HW infection.ResultsPH 12 was 100% effective in preventing HW disease in all three of these studies. In the laboratory studies, no PH 12-treated dogs had any adult HWs, whereas all control dogs in both studies had adult HWs [geometric mean, 30.2 (range, 22–37) for Study 1 and 32.6 (22–44) for Study 2]. In the field study, all dogs treated with PH 12 tested negative for adult HW infection on all test days (Days, 365, 480 and 605), whereas four dogs receiving HG Plus (positive control) tested positive for HWs during the study (three dogs on Day 365 and one dog on Day 480). All four dogs treated with HG Plus that subsequently tested positive for HWs during the field study were from the lower Mississippi River Valley region, where HW resistance to macrocyclic lactone preventives has been confirmed to occur. PH 12 was significantly better than HG Plus in preventing heartworm disease in the field study (P = 0.0367). PH 12 was well-tolerated in both laboratory and field studies.ConclusionsA single dose of ProHeart® 12 was 100% effective in preventing heartworm disease in dogs for a full year in both laboratory and field studies.

To evaluate the effects of napping, caffeine, and napping plus caffeine on performance and alertness in both laboratory and field settings. (1) Laboratory Study: parallel-groups design with random assignment to 1 of 4 experimental conditions. (2) Field Study: crossover design. Sleep laboratory and field settings. (1) Laboratory Study: 68 healthy individuals; (2) Field Study: 53 shiftworkers who worked nights or rotating shifts. (1) Laboratory Study: an evening nap opportunity before the first 2 of 4 consecutive simulated night shifts plus placebo taken all 4 nights, caffeine taken nightly, the combination of the nap and caffeine conditions, or placebo. (2) Field Study: an evening nap on the first 2 of 4 consecutive night shifts plus caffeine taken nightly versus placebo taken nightly without naps. (1) Laboratory Study: Napping, caffeine, and their combination all improved alertness and performance as measured by Maintenance of Wakefulness Test and Psychomotor Vigilance Task, but the combination of napping and caffeine was best in improving alertness. (2) Field Study: Napping plus caffeine improved performance as measured by Psychomotor Vigilance Test and decreased subjective sleepiness in individuals working the night shift. Napping plus caffeine helps improve performance and alertness of night-shift workers.

Pronghorn (Antilocapra americana) fawns were successfully hand-reared and trained for both laboratory and field studies in nutrition. Fawns were captured 1 to 3 days after birth, placed in an outdoor rearing facility, and bottle-fed a formula of 1 part evaporated milk and 4 parts homogenized milk. Dietary disorder and bacterial infection resulting in diarrhea, and bone and joint ailments were major problems encountered in rearing fawns. Seventy-four percent of 32 fawns reared were successfully trained for field and laboratory studies. J. WILDL. MANAGE. 40(3):464-468 Use of tame ungulates to study food habits under controlled conditions has increased in the past decade. As cited by Reichert (1972), investigators have used red deer (Cervus elaphus), caribou (Rangifer tarandus), white-tailed deer (Odocoileus virginianus), and mule deer (0. hemionus) for such purposes. Tame pronghorns have been used successfully for both field (Hoover 1971, Schwartz and Nagy 1973) and laboratory (Wesley et al. 1969, 1970, 1973) studies of nutrition, and in field studies of behavior (Ellis and Travis 1975). This report describes techniques used in rearing and training 35 pronghorn fawns captured in the wild. We acknowledge K. Miller for assistance with care and training of pronghorns, R. Souther for maintenance of animals, and D. Wesley and J. Hoover for suggestions throughout the study. J. Ellis, L. Menges, and 0. C. Wallmo reviewed the manuscript.

Carbon sequestration in agricultural soils may help to reduce global greenhouse gas concentrations, but building up soil carbon levels requires accumulating organic matter faster than it is lost via heterotrophic respiration. Using field and laboratory studies, this study sought to elucidate how tillage, the below‐ground incorporation of cover crop residue, and soil macroporosity affect soil respiration and residue decomposition rates. In the field, residue from a cover crop mixture of barley ( Hordeum vulgare ) and crimson clover ( Trifolium incarnatum ) was placed into litter bags that were left on the surface versus incorporated into the soil at three depths (4, 8 or 12 cm), while the laboratory study compared surface‐placed versus incorporated litter (8 cm depth). To assess tillage effects on cover crop decomposition, the field study simulated no‐till and conventional tillage treatments, while the laboratory and field studies both included treatments in which artificial soil macropores were created. The field study showed that conventional tillage and the presence of macropores enhanced soil respiration, while in the laboratory study, incorporating cover crop residue resulted in higher soil respiration and faster litter decomposition rates. Additionally, the laboratory measurements showed that macropores increased soil respiration in wet conditions, likely by enhancing oxygen diffusion. Thus, organic matter incorporation and macropores may represent important factors that affect soil respiration and carbon dynamics.

Do indoor plants improve performance and well-being in offices? Divergent results from laboratory and field studies