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Metacognition refers to thinking about one’s thinking or knowing what one knows. Research suggests that this ability is not unique to humans and may be shared with nonhuman animals. In particular, great apes have shown behaviors on a variety of tasks that are suggestive of metacognitive ability. Here we combine a metacognitive task, the information-seeking task, with tool use and variable forms of initial information provided to chimpanzees to explore how informational states impact behavioral responses in these apes. Three chimpanzees were presented with an apparatus that contained five locations where food could be hidden. If they pointed to the correct location, they received the reward, but otherwise they did not. We first replicated several existing findings using this method, and then tested novel hypotheses. The chimpanzees were given different types of information across the experiments. Sometimes, they were shown the location of the food reward. Other times, they were shown only one empty location, which was not useful information. The chimpanzees also could use a tool to search any of those locations before making a selection. Chimpanzees typically used the tool to search out the location of the reward when they could not already know where it was, but they did not use the tool when they already had been given that information. One chimpanzee made inferences about the location of hidden food, even when that food was never shown in that location. The final experiment involved hiding foods of differing preference values, and then presenting the chimpanzees with different initial knowledge states (i.e., where the best food was located, where the less-preferred food was located, or where no food was located). All chimpanzees used the tool when they needed to use it to find the best possible item on that trial, but responded by choosing a location immediately when they did not need the tool. This finding highlights that their behavior was not the result of a simple rule following such as pointing to where any food had been seen. [ABSTRACT FROM AUTHOR]

Aim The Australian Coptotermes (Family: Rhinotermitidae) are a small monophyletic group of termites, some of which build mounds. In this study, we construct predicted distributions based on environmental data (niche models) for all Australian species of Coptotermes to test whether specific environmental factors have contributed to the evolution of mound-building behaviour and whether the degree of niche similarity and degree of phylogenetic similarity are correlated. Location The Australian mainland, including the known native ranges of all Australian species of Coptotermes. Methods We estimated the phylogenetic relationships between the species of Australian Coptotermes. We then generated and compared environmental niche models in a phylogenetic framework for all study species to test niche conservation. Our analyses were based on location data from our own sampling and from the Atlas of Living Australia, genetic data from a previous study of Australian Coptotermes, and environmental data from WorldClim and ASRIS. Results We found that no environmental variable differed consistently between mound-building and non-mound-building taxa and that the differences in niches between pairs of Australian species of Coptotermes are uncorrelated with time since divergence. The environmental tolerances of the Australian Coptotermes termites are more restricted by rainfall than they are by soil or temperature. Main conclusions Our results show that mound-building behaviour has not necessarily evolved in response to similar abiotic conditions. Our results are consistent with ecological speciation leading to niche divergence since Coptotermes first arrived in Australia ~12.5 million years ago. [ABSTRACT FROM AUTHOR]

Integrative taxonomy, including molecular, morphological, distributional and biological data, is applied in a review of the taxonomy of the Australian species of the pest termite genus Coptotermes. The validity of the previously described species is discussed, and two new species, Coptotermes nanus, sp. nov. and Coptotermes cooloola, sp. nov., are described from the Kimberley region of Western Australia and south-east Queensland respectively. Their delimitation is based on morphological and distributional data, and the results of generalised mixed Yule-coalescent analysis of mitochondrial DNA sequence data. Images of the external view of the two new species are provided, as well as a key, based on soldier characters, for all Australian species of Coptotermes. [ABSTRACT FROM AUTHOR]

Predator and prey relationships are dynamic and interrelated. Thus, any offensive behaviour will vary according to differing defensive behaviours, or vice versa, within each species in any predator-prey system. However, most studies are one-sided as they focus on just one behaviour, that of either the predator or prey. Here, we examine both predatory behaviour of an oophagus katydid and antipredator behaviour by a frog with egg-stage parental care. Katydid offensive behaviour and predation success was greater in females and increased with predator maturity and size. Frog defensive behaviour was sex specific, probably because only mothers provide parental care. Defensive behaviour could be active, such as charging predators, or passive, such as sheltering eggs, with greater active defence against larger predators; neither was influenced by offspring age. These results are contrary to existing theory, which argues parental investment ought to be negatively correlated with parental predation risks and affected by offspring age. This study highlights the use of antipredator behaviour to test predictions of parental investment theories in amphibians. In addition, it illustrates the need to consider factors that influence both species concurrently when examining the complex interaction between predators and parents. [ABSTRACT FROM AUTHOR]

1. The ecosystem service of predation of weed seeds by naturally occurring seed-eating animals, including ants, in agricultural fields has been suggested to be a potentially important biocontrol option. Laboratory and field tests have found high levels of seed removal from experimentally placed seed; however, the effect of predation on naturally dispersed weed seeds is unknown. We measured the effect of invertebrate seed predators on natural weed seed dispersal and germination in a field experiment under commercial growing conditions. 2. The two-factor, large-scale field experiment in a field used to grow wheat with conservation tillage used an insecticide to remove soil invertebrates (ants had been reduced by 85% relative to water controls) and shallow tillage for mechanical weed removal (no effect on ants). There was one natural weed seeding event, when a wind storm blew one single incursion of Salsola australis (Chenopodiaceae) tumbleweeds across the field. 3. We measured the number of tumbleweeds after 2 months and found the removal of ants resulted in a doubling of tumbleweeds: 3383 ± 513 weeds ha -1 in the insecticide treatment plots compared with 1768 ± 100 weeds ha -1 in the water control treatment plots, and 1948 ± 227 weeds ha ±1 in the rest of the field. 4. The difference in tumbleweed germination and growth was not due to growing conditions. We measured soil nutrients before the incursion and soil moisture during the weed growing period and found that there were higher levels of nitrogenous compounds in water control plots, but no other nutrient or moisture differences, than in insecticide exclusion plots. 5. Synthesis and applications. Our results provide evidence that the ecosystem service of ant predation of naturally dispersed weed seeds limits weed abundance in commercial cereal fields in warmer climates. The fields were not managed to increase ants; alternative conservation agricultural management methods that promote agro-ecology, including low or zero tillage and low insecticide use, could increase ant abundance and thereby reduce weeds. The use of seed predators as a type of biocontrol agent will need to be integrated with other weed management methods, including herbicides and shallow tillage, although the latter may conflict with ant survival. The use of seed predators may be particularly advantageous in organic systems, or locations where economic margins are low. [ABSTRACT FROM AUTHOR]

The asymmetric dominance effect (or decoy effect) is a form of context-dependent choice bias in which the probability of choosing one of two options is impacted by the introduction of a third option, also known as the decoy. Decoy effects are documented widely within the human consumer choice literature, and even extend to preference testing within nonhuman animals. Here, we extended this line of research to a perceptual discrimination task with rhesus monkeys to determine whether decoy stimuli would impact size judgments of rectangular stimuli. In a computerized task, monkeys attempted to choose the larger of two rectangles that varied in size and orientation (horizontally or vertically oriented). In probe trials, a third stimulus (the decoy) was presented that was smaller than the other two rectangles but matched the orientation of one of them. On half of the probe trials, the presented decoy matched the orientation of the larger stimulus, and on the other half, the decoy matched the orientation of the smaller stimulus. Monkeys rarely selected the decoy stimulus. However, their performance (selection of the largest rectangle) increased relative to the baseline trials (with only two choices) when the decoy was congruent in its orientation with the largest rectangle, but decreased relative to baseline when the decoy was incongruent with the largest rectangle. Thus, a decoy stimulus impacted monkeys' perceptual choice behavior even when it was not a viable choice option itself. These results are explained with regard to comparative evaluation mechanisms. [ABSTRACT FROM AUTHOR]

Metacognition, the monitoring of one's own mental states, is a fundamental aspect of human intellect. Despite tests in nonhuman animals suggestive of uncertainty monitoring, some authors interpret these results solely in terms of primitive psychological mechanisms and reinforcement regimes, where 'reinforcement' is invariably considered to be the delivery and consumption of earned food rewards. Surprisingly, few studies have detailed the trial-by-trial behaviour of animals engaged in such tasks. Here we report ethology-based observations on a rhesus monkey completing sparse-dense discrimination problems, and given the option of escaping trials (i.e., responding 'uncertain') at its own choosing. Uncertainty responses were generally made on trials of high objective difficulty, and were characterized by long latencies before beginning visible trials, long times taken for response, and, even after controlling for difficulty, high degrees of wavering during response. Incorrect responses were also common in trials of high objective difficulty, but were characterized by low degrees of wavering. This speaks to the likely adaptive nature of 'hesitation', and is inconsistent with models which argue or predict implicit, inflexible information-seeking or 'alternative option' behaviours whenever challenging problems present themselves. Confounding models which suggest that nonhuman behaviour in metacognition tasks is driven solely by food delivery/consumption, the monkey was also observed allowing pellets to accumulate and consuming them during and after trials of all response/outcome categories (i.e., whether correct, incorrect, or escaped). This study thus bolsters previous findings that rhesus monkey behaviour in metacognition tasks is in some respects disassociated from mere food delivery/consumption, or even the avoidance of punishment. These and other observations fit well with the evolutionary status and natural proclivities of rhesus monkeys, but weaken arguments that responses in such tests are solely associated with associative mechanisms, and instead suggest more derived and controlled cognitive processing. The latter interpretation appears particularly parsimonious given the neurological adaptations of primates, as well as their highly flexible social and ecological behaviour. [ABSTRACT FROM AUTHOR]

Decision-making largely is influenced by the relative value of choice options, and the value of such options can be determined by a combination of different factors (e.g., the quantity, size, or quality of a stimulus). In this study, we examined the competing influences of quantity (i.e., the number of food items in a set) and quality (i.e., the original state of a food item) of choice items on chimpanzees’ food preferences in a two-option natural choice paradigm. In Experiment 1, chimpanzees chose between sets of food items that were either entirely whole or included items that were broken into pieces before being shown to the chimpanzees. Chimpanzees exhibited a bias for whole food items even when such choice options consisted of a smaller overall quantity of food than the sets containing broken items. In Experiment 2, chimpanzees chose between sets of entirely whole food items and sets of initially whole items that were subsequently broken in view of the chimpanzees just before choice time. Chimpanzees continued to exhibit a bias for sets of whole items. In Experiment 3, chimpanzees chose between sets of new food items that were initially discrete but were subsequently transformed into a larger cohesive unit. Here, chimpanzees were biased to choose the discrete sets that retained their original qualitative state rather than toward the cohesive or clumped sets. These results demonstrate that beyond a food set's quantity (i.e., the value dimension that accounts for maximization in terms of caloric intake), other seemingly non-relevant features (i.e., quality in terms of a set's original state) affect how chimpanzees assign value to their choice options. [ABSTRACT FROM AUTHOR]

Prospective memory is remembering to do something at a future time. A growing body of research supports that prospective memory may exist in nonhuman animals, but the methods used to test nonhuman prospective memory differ from those used with humans. The current work tests prospective memory in chimpanzees using a method that closely approximates a typical human paradigm. In these experiments, the prospective memory cue was embedded within an ongoing task. Tokens representing food items could be used in one of two ways: in a matching task with pictures of items (the ongoing task) or to request a food item hidden in a different location at the beginning of the trial. Chimpanzees had to disengage from the ongoing task in order to use the appropriate token to obtain a higher preference food item. In , chimpanzees effectively matched tokens to pictures, when appropriate, and disengaged from the ongoing task when the token matched the hidden item. In , performance did not differ when the target item was either hidden or visible. This suggested no effect of cognitive load on either the prospective memory task or the ongoing task, but performance was near ceiling, which may have contributed to this outcome. In , we created a more challenging version of the task. More errors on the matching task occurred before the prospective memory had been carried out, and this difference seemed to be limited to the hidden condition. This finding parallels results from human studies and suggests that working memory load and prospective memory may have a similar relationship in nonhuman primates. [ABSTRACT FROM AUTHOR]

Insects breathe using one or a combination of three gas exchange patterns; continuous, cyclic and discontinuous, which vary in their rates of exchange of oxygen, carbon dioxide and water. In general, there is a trade-off between lowering gas exchange using discontinuous exchange that limits water loss at the cost of lower metabolic rate. These patterns and hypotheses for the evolution of discontinuous exchange have been examined for relatively large insects (>20 mg) over relatively short periods (<4 h), but smaller insects and longer time periods have yet to be examined. We measured gas exchange patterns and metabolic rates for adults of a small insect pest of grain, the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), using flow-through respirometry in dry air for 48 h. All adults survived the desiccating measurement period; initially they used continuous gas exchange, then after 24 h switched to cyclic gas exchange with a 27% decrease in metabolic rate, and then after 48 h switched to discontinuous gas exchange with increased interburst duration and further decrease in metabolic rate. The successful use of the Qubit, a lower cost and so more common gas analyser, to measure respiration in the very small T. castaneum , may prompt more flow-through respirometry studies of small insects. Running such studies over long durations may help to better understand the evolution of respiration physiology and thus suggest new methods of pest management. [ABSTRACT FROM AUTHOR]

Both empirical and anecdotal evidence supports the idea that choice is preferred by humans. Previous research has demonstrated that this preference extends to nonhuman animals, but it remains largely unknown whether animals will actively seek out or prefer opportunities to choose. Here we explored the issue of whether capuchin and rhesus monkeys choose to choose. We used a modified version of the SELECT task-a computer program in which monkeys can choose the order of completion of various psychomotor and cognitive tasks. In the present experiments, each trial began with a choice between two icons, one of which allowed the monkey to select the order of task completion, and the other of which led to the assignment of a task order by the computer. In either case, subjects still had to complete the same number of tasks and the same number of task trials. The tasks were relatively easy, and the monkeys responded correctly on most trials. Thus, global reinforcement rates were approximately equated across conditions. The only difference was whether the monkey chose the task order or it was assigned, thus isolating the act of choosing. Given sufficient experience with the task icons, all monkeys showed a significant preference for choice when the alternative was a randomly assigned order of tasks. To a lesser extent, some of the monkeys maintained a preference for choice over a preferred, but computer-assigned, task order that was yoked to their own previous choice selection. The results indicated that monkeys prefer to choose when all other aspects of the task are equated. [ABSTRACT FROM AUTHOR]

Self-control has been studied in nonhuman animals using a variety of tasks. The inter-temporal choice (ITC) task presents choices between smaller-sooner (SS) and larger-later (LL) options. Using food amounts as rewards, this presents two problems: (a) choices of the LL option could either reflect self-control or instead result from animals' difficulty with pointing to smaller amounts of food; (b) there is no way to verify whether the subjects would not revert their choice for the LL option, if given the opportunity to do so during the ensuing delay. To address these problems, we have recently introduced a new protocol, the hybrid delay task, which combines an initial ITC with a subsequent accumulation phase in which selection of the SS option leads to its immediate delivery, but choice of the LL option then leads to one-by-one presentation of those items that continues only as long as the subject does not eat any of the accumulated items. The choice of the LL option therefore only reflects self-control when the number of items obtained from LL choices during the accumulation phase is higher than what could be received in the SS option. Previous research with capuchin monkeys demonstrated that their apparent self-control responses in the ITC task may have overestimated their general self-control abilities, given their poor performance in the hybrid delay task. Here, chimpanzees instead demonstrated that their choices for the LL option in the ITC phase of the hybrid delay task were confirmed by their ability to sustain long delays during accumulation of LL rewards. [ABSTRACT FROM AUTHOR]

Prospective memory (PM) involves remembering to do something at a specific time in the future. Here, we investigate the beginnings of this ability in young children (3-year-olds; Homo sapiens) and chimpanzees ( Pan troglodytes) using an analogous task. Subjects were given a choice between two toys (children) or two food items (chimpanzees). The selected item was delivered immediately, whereas the unselected item was hidden in an opaque container. After completing an ongoing quantity discrimination task, subjects could request the hidden item by asking for it (children) or by pointing to the container and identifying the item on a symbol board (chimpanzees). Children and chimpanzees showed evidence of prospective-like memory in this task, as evidenced by successful retrieval of the item at the end of the task, sometimes spontaneously with no prompting from the experimenter. These findings contribute to our understanding of PM from an ontogenetic and comparative perspective. [ABSTRACT FROM AUTHOR]

Highlights: [•] Monkeys perform reliably in computerized inter-temporal choice self-control tests. [•] Rhesus monkeys perform equally in self-control tests involving effort and delay. [•] Capuchin monkeys exhibit more self-control in delay-based than in effort-based tests. [•] Performance differences between tests may relate to species’ natural history. [ABSTRACT FROM AUTHOR]

Choice tests are a standard method to determine preferences in bio-assays, e.g. for food types and food additives such as bait attractants and toxicants. Choice between food additives can be determined only when the food substrate is sufficiently homogeneous. This is difficult to achieve for wood eating organisms as wood is a highly variable biological material, even within a tree species due to the age of the tree (e.g. sapwood vs. heartwood), and components therein (sugar, starch, cellulose and lignin). The current practice to minimise variation is to use wood from the same tree, yet the variation can still be large and the quantity of wood from one tree may be insufficient. We used wood samples of identical volume from multiple sources, measured three physical properties (dry weight, moisture absorption and reflected light intensity), then ranked and clustered the samples using fuzzy c-means clustering. A reverse analysis of the clustered samples found a high correlation between their physical properties and their source of origin. This suggested approach allows a quantifiable, consistent, repeatable, simple and quick method to maximize control over similarity of wood used in choice tests. [ABSTRACT FROM AUTHOR]

The Monty Hall Dilemma (MHD) is a well-known probability puzzle in which players try to guess which of three doors conceals a prize. After selecting a door, players are shown that there is no prize behind one of the remaining doors. Players then are given a choice to stay with their door or switch to the other unopened door. Most people stay, even though switching doubles the probability of winning. The MHD offers one of the clearest examples of irrational choice behavior in humans. The present experiment investigated how monkeys and humans would behave when presented with a computerized version of the MHD. Specifically, we were interested in whether monkeys were more likely to engage in a switching strategy than humans and whether both species could learn to switch with repeated trials. Initially, humans and monkeys showed indifference between the two options of either staying with their initial choice or switching. With experience, members of both species learned to use the switch strategy at above chance levels, but there were individual differences with only approximately half of the participants in each species learning to choose the more optimal response. Thus, humans and monkeys showed similar capacity to adjust their responding as a result of increased experience with this probabilistic task. [ABSTRACT FROM AUTHOR]

The number of recognized invasive termite species has increased from 17 in 1969 to 28 today. Fourteen species have been added to the list in the past 44 years; 10 have larger distributions and 4 have no reported change in distribution, and 3 species are no longer considered invasive. Although most research has focused on invasive termites in urban areas, molecular identification methods have answered questions about certain species and found that at least six species have invaded natural forest habitats. All invasive species share three characteristics that together increase the probability of creating viable propagules: they eat wood, nest in food, and easily generate secondary reproductives. These characteristics are most common in two families, the Kalotermitidae and Rhinotermitidae (which make up 21 species on the invasive termite list), particularly in three genera, Cryptotermes, Heterotermes, and Coptotermes (which together make up 16 species). Although it is the largest termite family, the Termitidae (comprising 70% of all termite species) have only two invasive species, because relatively few species have these characteristics. Islands have double the number of invasive species that continents do, with islands in the South Pacific the most invaded geographical region. Most invasive species originate from Southeast Asia. The standard control methods normally used against native pest termites are also employed against invasive termites; only two eradication attempts, in South Africa and New Zealand, appear to have been successful, both against Coptotermes species. [ABSTRACT FROM AUTHOR]

Abstract: Prospective memory (PM) involves forming intentions, retaining those intentions, and later executing those intended responses at the appropriate time. Few studies have investigated this capacity in animals. Monkeys performed a computerized task that assessed their ability to remember to make a particular response if they observed a PM cue embedded within an ongoing learning-set (LS) task. At a break in the LS task, monkeys selected one of two icons indicating that they had or had not encoded the occurrence of the PM cue (the latter icon resumed the LS task). Critically, during this response period, the PM response icon appeared after a delay during which monkeys could self-initiate the PM response prior to receiving any external prompt. Monkeys selected the PM and LS icons when each was the optimal response, illustrating that they could encode, store, and respond appropriately to a stimulus event in the future. Critically, some monkeys self-initiated the PM response prior to that icon’s appearance, indicating that they could retrieve the PM and act on their intention to make that response without the aid of a prompt. These monkeys appeared capable of using PM in this task. Thus, this capacity appears not to be limited to humans. [Copyright &y& Elsevier]

Token exchange inherently introduces an element of delay between behavior and reward and so token studies may help us better understand delay of gratification and self-control. To examine this possibility, we presented three language-trained chimpanzees with repeated choices involving different foods that could be eaten immediately or lexigram (graphic symbol) tokens that represented (and could be traded for) foods later. When both options were foods, chimpanzees always chose more preferred foods over less preferred foods. When both options were lexigram tokens representing those same foods, performance remained the same as chimpanzees selected the higher value token and then traded it for food. Then, when faced with choosing a token that could be traded later or choosing a food item that could be eaten immediately, most chimpanzees learned to make whatever response led to the more preferred food. They did this even when that meant selecting a high value lexigram token that could be traded only 2 to 3 min later instead of a medium value, but immediately available, food item. Thus, chimpanzees flexibly selected tokens even though such selections necessarily delayed gratification and required forgoing immediately available food. This finding illustrates the utility of symbolic token exchange for assessing self-control in nonhuman animals. Am. J. Primatol. 74:864-870, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Planning is an important aspect of many daily activities for humans. Planning involves forming a strategy in anticipation of a future need. However, evidence that nonhuman animals can plan for future situations is limited, particularly in relation to the many other kinds of cognitive capacities that they appear to share with humans. One critical aspect of planning is the ability to remember future responses, or what is called prospective coding. Two monkey species (Macaca mulatta and Cebus apella) performed a series of computerized tasks that required encoding a future response at the outset of each trial. Monkeys of both species showed competence in all tests that were given, providing evidence that they anticipated future responses and that they appropriately engaged in those responses when the time was right for such responses. In addition, some tests demonstrated that monkeys even remembered future responses that were not as presently motivating as were other aspects of the task environment. These results indicated that monkeys could anticipate future responses and retain and implement those responses when appro-priate. [ABSTRACT FROM AUTHOR]

Self-control is often required in natural situations involving interactions with other individuals, and personal self-control can be compromised if other individuals act impulsively. In this study, we tested self-control in pairs of chimpanzees in a variety of settings where at least one chimpanzee of each pair performed an established test for self-control in which candies accumulated one at time as long as the chimpanzee did not eat any of them. When tested alone, some chimpanzees exhibited greater self-control as compared to when tested alongside a chimpanzee that independently performed the same type of test. However, when the nonfocal animal freely consumed rewards while the focal chimpanzee performed the accumulation task, the self-control of some focal chimpanzees was elevated as compared to when working alone. Finally, when the focal and nonfocal animals worked jointly on the same test and the number of rewards accumulated was dependent on both animals' continued ability to inhibit eating the items, chimpanzees performed the same when housed together or in adjacent enclosures. On the whole, the effects of social setting were modest, but these results may relate to the literature on vicarious depletion of self-control, and they present interesting avenues for future research. [ABSTRACT FROM AUTHOR]

The literature on pairing and mating behavior in termites indicates that a number of distal antennal segments in dealates of both sexes are often removed during colony foundation, with terms such as amputation, mutilation and cannibalism typically employed to report the phenomenon. Here we propose the use of the phrase 'antennal cropping' to describe the behavior, and assess naturally occurring levels of its occurrence by comparing the number of antennal segments in museum specimens of alates and dealates in 16 species of Australian termites (four families), supplemented by analyzing published data on Coptotermes gestroi. Dealates had significantly fewer antennal segments than alates in 14 of the 16 termite species, with both exceptions belonging to the family Termitidae. Levels of antennal cropping were not significantly different between the sexes but did vary by family. Dealates in the Kalotermitidae removed the most segments (41.3%) and those in the Termitidae removed the fewest (8.9%). We discuss the biological significance of this phylogenetically widespread termite behavior, and suggest that controlled antennal cropping is not only a normal part of their behavioral repertoire but also a key influence that changes the conduct and physiology of the royal pair during the initial stages of colony foundation. [ABSTRACT FROM AUTHOR]

We presented four chimpanzees with a series of tasks that involved comparing two token sets or comparing a token set to a quantity of food. Selected tokens could be exchanged for food items on a one-to-one basis. Chimpanzees successfully selected the larger numerical set for comparisons of 1 to 5 items when both sets were visible and when sets were presented through one-by-one addition of tokens into two opaque containers. Two of four chimpanzees used the number of tokens and food items to guide responding in all conditions, rather than relying on token color, size, total amount, or duration of set presentation. These results demonstrate that judgments of simultaneous and sequential sets of stimuli are made by some chimpanzees on the basis of the numerousness of sets rather than other non-numerical dimensions. The tokens were treated as equivalent to food items on the basis of their numerousness, and the chimpanzees maximized reward by choosing the larger number of items in all situations. [ABSTRACT FROM AUTHOR]

It is unclear whether nonhuman animals can use physical tokens to flexibly represent various quantities by combining token values. Previous studies showed that chimpanzees (Pan troglodytes) and a macaque (Macaca inulatta) were only partly successful in tests involving sets of different-looking food containers representing different food quantities, while some capuchin monkeys (Cebus ape/la) have shown greater success in tests involving sets of various concrete objects representing different food quantities. Some of the discrepancy in results between these studies may be attributed to the different methods used. In an effort to reconcile these discrepancies, we presented two primates species, chimpanzees and capuchin monkeys, with two token tasks. The critical test in each task involved summing the value of multiple tokens of different types to make accurate quantity judgments. We found that, using either method, individuals of both species learned to associate individual tokens with specific quantities, as well as successfully compare individual tokens to one another or to sets of visible food items. However, regardless of method, only a few individuals exhibited the capacity to sum multiple tokens of different types and then use those summed values to make an optimal response. This suggests that flexible combination of symbolic stimuli in quantity judgments tasks is within the abilities of chimpanzees and capuchins but does not characterize the majority of individuals. Furthermore, the results suggest the need to carefully examine specific methodological details that may promote or hinder such possible representation. [ABSTRACT FROM AUTHOR]

Competition exclusion, when a single species dominates resources due to superior competitiveness, is seldom observed in nature. Termites compete for resources with deadly consequences, yet more than one species can be found feeding in the same wooden resource. This is especially surprising when drywood species, with colonies of a few hundred, are found cohabiting with subterranean species, with colonies of millions. Termites communicate vibro-acoustically and, as these signals can travel over long distances, they are vulnerable to eavesdropping. We investigated whether drywood termites could eavesdrop on vibration cues from subterranean species. We show, using choice experiments and recordings, that the drywood termite Cryptotermes secundus can distinguish its own species from the dominant competitor in the environment, the subterranean termite Coptotermes acinaciformis. The drywood termite was attracted to its own vibration cues, but was repelled by those of the subterranean species. This response increased with decreasing wood size, corresponding with both increased risk and strength of the cue. The drywood termites appear to avoid confrontation by eavesdropping on the subterranean termites; these results provide further evidence that vibro-acoustic cues are important for termite sensory perception and communication. [ABSTRACT FROM AUTHOR]

The authors investigated choice behavior by chimpanzees in five experiments involving choices between different amounts of food. Chimpanzees did not maximize the amount of food they obtained when choosing between a single 20-g banana piece and another option containing a 20-g piece and a 5-g piece. This was true even though they successfully discriminated between 20-g and 25-g banana pieces in other trials. When items in the mixed option were stacked, however, the chimpanzees chose the larger amount. Later experiments indicated that changing the magnitude of the two amounts did not change performance if the difference in magnitude between the two options remained the same (e.g., 40 g plus 10 g vs. 40 g). However, chimpanzees did improve when the two-item option was increased in its magnitude relative to the single slice (e.g., 20 g plus 10 g vs. 20 g). These results indicated that chimpanzees undervalued the total amount of food in sets when items differed in size and did not appear to be whole. Another experiment confirmed that it was this notion of wholeness that evoked suboptimal responding because chimpanzees were successful in the same comparisons with a different type of food that appeared less fractionated when presented as two pieces. These results provide evidence of suboptimal responding in some natural choice situations that prevents chimpanzees from maximizing food intake. [ABSTRACT FROM AUTHOR]

Abstract: We tested four chimpanzees in a self-control task in which food rewards accumulated as long as they were not eaten. In one condition, the chimpanzees had to perform a computer task that directly led to the delivery of the food rewards. In another condition, working on the computerized task was not required and any such work was not linked to the delivery of rewards. The third condition offered no computerized task (chimpanzees simply waited for food rewards to be delivered). Three of four chimpanzees showed no effect of the work scenario on delay of gratification. The one chimpanzee that showed an influence of work scenario on self-control was the overall poorest performing animal. This animal delayed gratification the longest, however, when work was required and reward delivery was directly linked to that work. Therefore, although there is little evidence linking delay of gratification to work requirements in chimpanzees, chimpanzees with lower overall self-control might benefit from having some work available if reward accumulation is contingent on performing that work. [Copyright &y& Elsevier]

Recent assessments have shown that capuchin monkeys, like chimpanzees and other Old World primate species, are sensitive to quantitative differences between sets of visible stimuli. In the present study, we examined capuchins’ performance in a more sophisticated quantity judgment task that required the ability to form representations of food quantities while viewing the quantities only one piece at a time. In three experiments, we presented monkeys with the choice between two sets of discrete homogeneous food items and allowed the monkeys to consume the set of their choice. In Experiments 1 and 2, monkeys compared an entirely visible food set to a second set, presented item-by-item into an opaque container. All monkeys exhibited high accuracy in choosing the larger set, even when the entirely visible set was presented last, preventing the use of one-to-one item correspondence to compare quantities. In Experiment 3, monkeys compared two sets that were each presented item-by-item into opaque containers, but at different rates to control for temporal cues. Some monkeys performed well in this experiment, though others exhibited near-chance performance, suggesting that this species’ ability to form representations of food quantities may be limited compared to previously tested species such as chimpanzees. Overall, these findings support the analog magnitude model of quantity representation as an explanation for capuchin monkeys’ quantification of sequentially presented food items. [ABSTRACT FROM AUTHOR]

Even with advances in automated testing techniques, the capuchin monkey (Cebus apella) can be a difficult species to test in the laboratory, given its social/behavioral tendencies and typical activity pattern. Laboratories that maintain social colonies of capuchin monkeys are able to separate and test individuals, but the process can be very effortful and time consuming, and the resulting data can be modest in quantity. The present article describes procedures and apparatuses that were used to train a colony of computer-naive capuchin monkeys to quickly and reliably isolate themselves from group members and interact with a computerized test system in order to produce a large volume of data. Several elements that were important in motivating the monkeys to participate are discussed. [ABSTRACT FROM AUTHOR]

Nonhuman animals reliably select the largest of two or more sets of discrete items, particularly if those items are food items. However, many studies of these numerousness judgements fail to control for confounds between amount of food (e.g. mass or volume) and number of food items. Stimulus dimensions other than number of items also may influence how animals perceive sets and make choices. Four chimpanzees, Pan troglodytes, completed a variety of tasks that involved comparisons of food items (graham crackers) that varied in number, size and orientation. In experiment 1, chimpanzees chose between two alternative sets of visible cracker pieces. In experiment 2, the experimenters presented one set of crackers in a vertical orientation (stacked) and the other in a horizontal orientation. In experiment 3, the experimenters presented all food items one at a time by dropping them into opaque containers. Chimpanzees succeeded overall in choosing the largest amount of food. They did not rely on number or contour length as cues when making these judgements but instead primarily responded to the total amount of food in the sets. However, some errors reflected choices of the set with the smaller total amount of food but the individually largest single food item. Thus, responses were not optimal because of biases that were not related to the total amount of food in the sets. [Copyright &y& Elsevier]

Capuchin monkeys (Cebus apella) were presented with two sets of food items, identical in food type but differing in number. Animals selected one set and were permitted to consume their choice. Set sizes ranged from 1 to 6 items. In experiment 1, each set was uncovered and recovered before a response was made, and the monkeys selected the larger set at high levels. Experiment 2 presented sets that had both visible and nonvisible food items in them at the time of the response, thus requiring the monkeys to sum the total amount of food that was available. The monkeys again selected the larger set with no decrement in performance. Overall, the data indicate that capuchins, like other more extensively studied primate species in this area of research, are responsive to quantitative differences between sets. Capuchins succeed in making these quantity judgments when sets are nonvisible at choice time and when summation of items must be performed, thus demonstrating coordination of quantification skills and memory. Capuchins also inhibit responses to visible food items when those items are only part of an overall smaller quantity of food compared with a completely nonvisible set. Am. J. Primatol. 70:191–194, 2008. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Abstract: The variables of delay and effort have been found to influence self-control predictably and in similar fashion when tested independently, but it is unclear how they influence self-control interactively. In the present study, I tested these two variables simultaneously to gain better understanding of their combined influence on self-control. A computerized task was employed in which monkey participants could sequence 1 or more digital images before “cashing-out,” after which they would receive their accumulated rewards. Delay was manipulated by adjusting the speed of the cursor used to select images. Cognitive effort was manipulated by presenting image sets that appeared in either a constant or a randomized configuration. For most monkeys, an interaction was found between the effects of delay and effort on the number of images selected before cashing-out. The results suggest that, when combined, these two variables have a complex influence on self-control. [Copyright &y& Elsevier]

Three experiments were conducted to test whether a pair of tufted capuchin monkeys ( Cebus apella) could generalize their ability to exchange tokens and tool objects with a human experimenter to similar exchanges with a conspecific partner. Monkeys were tested in side-by-side enclosures, one enclosure containing a tool-use apparatus and one or more token(s), and the other enclosure containing one or more tool object(s). The monkeys willingly transferred tokens and tools to a conspecific with little practice. Following a small amount of training, we also found that the monkeys would select situation-appropriate tokens to exchange for specific tools, but did not select appropriate tool objects in response to another monkey’s token transfers. Implications regarding role reversal are discussed. [ABSTRACT FROM AUTHOR]

The authors tested the self-control of rhesus macaques by assessing if they could refrain from reaching into a food container to maximize the accumulation of sequentially delivered food items (a delay-maintenance task). Three different versions of the task varied the quantity and quality of available food items. In the first 2 versions, food items accumulated across the length of the trial until a monkey consumed the items. In the 3rd task, a single less-preferred food item preceded a single more-preferred food item. Some monkeys delayed gratification even with relatively long delays between deliveries of items. However, the data suggested that self-control, in the majority of tested individuals, was not significantly different across different task versions and that self-control by macaques was not as prevalent in these tasks as it is in chimpanzees and human children. [ABSTRACT FROM AUTHOR]

Abstract: Previous research in our laboratory has demonstrated that chimpanzees can delay gratification by inhibiting consumption of available food items for as long as 3min as an experimenter transfers additional food items from a transparent container to a bowl placed in front of the subject. In this study, we examined the influence of the visibility of the food source, as well as the presence of the experimenter, on four chimpanzees’ self-control in this paradigm. In Experiment 1 an experimenter transferred 15 preferred food items between a distant opaque container and a bowl placed in front of the subject. In Experiment 2 we tested the chimpanzees with an automated system that (in the absence of the experimenter) transferred up to 36 highly preferred food items from a universal food dispenser to a container located either inside or outside of the subject''s enclosure. There were no differences in self-directed behaviors or attentiveness to the food items between the self-imposed and externally imposed delay conditions. A final experiment with the automated paradigm indicated that individuals could delay gratification for up to 11min in order to obtain all 36 food items. [Copyright &y& Elsevier]

Self-control is defined as forgoing immediate gratification to obtain a greater reward. Tool use may relate to self-control because both behaviors may require foresight and deliberate control over one's actions. The authors assessed 20 capuchin monkeys (Cebus apella) for the ability to delay gratification in a tool task. Subjects were given rod-shaped food items that could either be consumed immediately or be carried to an apparatus and used to extract a more preferred food. The authors found that some monkeys were able to exhibit self-control. Monkeys with relatively more tool use experience demonstrated the greatest levels of self-control. These results indicate that capuchins are capable of delaying gratification when a higher quality reinforcer is present and that tool experience can influence levels of self-control in this task. [ABSTRACT FROM AUTHOR]

Research on cross-modal performance in nonhuman primates is limited to a small number of sensory modalities and testing methods. To broaden the scope of this research, the authors tested capuchin monkeys (Cebus apella) for a seldom-studied cross-modal capacity in nonhuman primates, auditory-visual recognition. Monkeys were simultaneously played 2 video recordings of a face producing different vocalizations and a sound recording of 1 of the vocalizations. Stimulus sets varied from naturally occurring conspecific vocalizations to experimentally controlled human speech stimuli. The authors found that monkeys preferred to view face recordings that matched presented vocal stimuli. Their preference did not differ significantly across stimulus species or other stimulus features. However, the reliability of the latter set of results may have been limited by sample size. From these results, the authors concluded that capuchin monkeys exhibit auditory-visual cross-modal perception of conspecific vocalizations. [ABSTRACT FROM AUTHOR]

Contrary to the common perception that termites are indiscriminant eaters, termites choose their food carefully; however, the methods by which they choose food are not well understood. Using choice experiments and recordings of termites feeding on wooden blocks of different sizes, we show that worker drywood termites (Cryptotermes domestkus) use the resonant frequency of a block of wood to assess its size. Drywood termites showed differences in their response to vibration recordings of termites compared with artificially generated signals, suggesting that they can discriminate the source of vibration Furthermore, fewer workers matured into neotenic reproductives when recorded termite signals were played, suggesting that vibration signals play an important role in termite communication. [ABSTRACT FROM AUTHOR]

Using techniques established by E. M. Brannon and H. S. Terrace (2000) with rhesus macaques (Macaca mulatta), the authors tested the ability of brown capuchins (Cebus apella) to order arrays of items ranging in quantity from 1 to 9. Three monkeys were trained on a touch screen to select the quantities 1-4 in ascending order. The monkeys exhibited successful transfer of this ability to novel representations of the quantities 1-4 and to pairs of the novel quantities 5-9. Patterns of responding with respect to numeric distance and magnitude were similar to those seen in human subjects, suggesting the use of similar psychological processes. The capuchins demonstrated an ordinal representation of quantity equivalent to that shown in Old World monkeys. [ABSTRACT FROM AUTHOR]

A tool-throwing task was used to test whether capuchin monkeys understand the difference between functionally appropriate and functionally inappropriate tools. A group of monkeys was trained to obtain a sticky treat from a container outside their enclosure using a projectile attached to one end of an anchored line. Subsequently, these monkeys were given choice tests between functional and nonfunctional versions of tools used in training. A different feature of the tool was varied between alternatives in each choice test. The monkeys chose to use functional tools significantly more often than nonfunctional tools in early exposures to each choice test. A second experiment tested whether these subjects, as well as a second group of minimally trained participants, could distinguish between functional and nonfunctional tools that appeared different from those used in training. A new set of design features was varied between tools in these choice tests. All participants continued to choose functional tools significantly more often than nonfunctional tools, regardless of their tool-throwing experience or the novel appearance of the tools. These results suggest that capuchin monkeys, like chimpanzees studied in similar experiments, are sensitive to a variety of functionally relevant tool features. [ABSTRACT FROM AUTHOR]

Abstract We characterized the population genetic structure of the Australian social spider Diaea ergandros using polymorphic allozyme markers. Our main objectives were to understand the social organization of D. ergandros and discern patterns of gene flow across distantly separated geographical areas. Spiders were sampled from nests located within 100 m wide locales, which were distributed within larger 50 km wide regions. Our results indicated that nestmates could have been produced by a single mother and father in 88.9% of D. ergandros nests. The remainder of nests contained spiders that were probably produced by polyandrous females or were immigrants from foreign nests. Nestmate relatedness was relatively high (r = 0.44) and did not differ significantly between the sexes or among juvenile, subadult and adult life stages. We also discovered that D. ergandros populations were highly structured, with significant differentiation detected among locales (F LR = 0.23) and regions (F RT = 0.081). Spiders within locales were also substantially inbred (F IL = 0.15). Overall, our data show that significant population subdivision exists in D. ergandros populations, and we suggest that the poor dispersal ability of Diaea spiders can account for the observed genetic structure. [ABSTRACT FROM AUTHOR]

1. Forager population size of two species of mound-building, subterranean termite (Coptotermes lacteus, Rhinotermitidae and Nasutitermes exitiosus, Termitidae) was estimated using three mark–recapture protocols. These estimates varied widely within and between colonies (≈ 0.3–200 million for C. lacteus and 0.2–3 million for N. exitiosus). The variation in the estimates is explained in part by violation of the assumptions of the protocols. 2. The fat-stain markers, although persistent in the laboratory, faded rapidly in the field, and were transferable from marked individuals to unmarked individuals by cannibalism. 3. Marked individuals did not mix randomly or evenly with unmarked foraging individuals in space or time, as marked individuals were recaptured in widely varying numbers at different feeding sites sampled simultaneously. Importantly, foragers displayed feeding site fidelity and avoided disturbed feeding sites. 4. The likelihood of recapture differed between castes and instars; there was a higher recapture rate of large workers and soldiers relative to smaller workers. 5. The mark–recapture protocols provided inaccurate and unreliable forager population estimates, up to two orders of magnitude larger than direct counts of entire mound colonies. Thus the weighted mean estimates from more complex triple-mark–recapture protocols were not necessarily better than Lincoln index estimates from simpler single-mark–recapture protocols. 6. Mark–recapture studies may provide useful information about forager behaviour and foraging territories. [ABSTRACT FROM AUTHOR]

The origin of the German cockroach, Blattella germanica, is enigmatic, in part because it is ubiquitous worldwide in human-built structures but absent from any natural habitats. The first historical records of this species are from ca. 250 years ago (ya) from central Europe (hence its name). However, recent research suggests that the center of diversity of the genus is Asian, where its closest relatives are found. To solve this paradox, we sampled genome-wide markers of 281 cockroaches from 17 countries across six continents. We confirm that B. germanica evolved from the Asian cockroach Blattella asahinai approximately 2,100 ya, probably by adapting to human settlements in India or Myanmar. Our genomic analyses reconstructed two primary global spread routes, one older, westward route to the Middle East coinciding with various Islamic dynasties (~1,200 ya), and another younger eastward route coinciding with the European colonial period (~390 ya). While Europe was not central to the early domestication and spread of the German cockroach, European advances in long-distance transportation and temperature-controlled housing were likely important for the more recent global spread, increasing chances of successful dispersal to and establishment in new regions. The global genetic structure of German cockroaches further supports our model, as it generally aligns with geopolitical boundaries, suggesting regional bridgehead populations established following the advent of international commerce. [ABSTRACT FROM AUTHOR]

Competition is a fundamental process in ecology and helps to determine dominance hierarchies. Competition and dominance hierarchies have been little investigated in wood-eating termites, despite the necessary traits of similar resources, and showing spatial and temporal overlap. Competition and dominance between five species of wood-eating termites found in Huangzhou, China, was investigated in three laboratory experiments of aggression and detection, plus a year-long field survey of termite foraging activity. Dominance depended on body size, with largest species winning overwhelmingly in paired contests with equal numbers of individuals, although the advantage was reduced in paired competitions with equal biomass. The termites could detect different species from used filter papers, as larger species searched through paper used by smaller species, and smaller species avoided papers used by larger species. The largest species maintained activity all year, but in low abundance, whereas the second largest species increased activity in summer, and the smallest species increased their activity in winter. The termite species displayed a dominance hierarchy based on fighting ability, with a temporal change in foraging to avoid larger, more dominant species. The low abundance of the largest species, here Macrotermes barneyi, may be a function of human disturbance, which allows subordinate species to increase. Thus, competitive release may explain the increase in abundance of pest species, such as Coptotermes formosanus, in highly modified areas, such as urban systems. [ABSTRACT FROM AUTHOR]

The ecosystem services provided by dung beetles are well known and valued. Dung beetles bury dung for feeding and breeding, and it is generally thought that the process of burying dung increases nutrient uptake by plant roots, which promotes plant growth. Many studies have tested the effects of dung beetles on plant growth, but there has been no quantitative synthesis of these studies. Here we use a multi-level meta-analysis to estimate the average effect of dung beetles on plant growth and investigate factors that moderate this effect. We identified 28 publications that investigated dung beetle effects on plant growth. Of these, 24 contained the minimum quantitative data necessary to include in a meta-analysis. Overall, we found that dung beetles increased plant growth by 17%; the 95% CI for possible values for the true increase in plant growth that were most compatible with our data, given our statistical model, ranged from 1% to 35%. We found evidence that the dung beetle–plant growth relationship is influenced by the plant measurement type and the number of beetles accessing the dung. However, beetles did not increase plant growth in all quantitative trials, as individual effect sizes ranged from −72% to 806%, suggesting important context-dependence in the provision of ecosystem services. [ABSTRACT FROM AUTHOR]

Insect biological control agents may be released in relatively few locations; thus, the rate of spread is critical to predicting the spatial distribution of the agent.Exotic dung beetles have been introduced into Australia since the 1960s to bury dung, reduce bush fly populations, increase pasture productivity and improve livestock health.We use a stochastic cellular automata model to predict the historical occupancy and abundance of introduced dung beetles in the South West agricultural region of Western Australia. The model predicts the spread of four species of dung beetles in six‐month time steps for 10 years following initial release. Our model includes release locations, species‐specific ecological parameters, dung resource availability and weather variables.The average rate of spread varied between species from a high of ca. 79 km/year (Euoniticellus intermedius) to a low of 28 km/year (Onthophagus taurus). Thus, after 10 years, the area of spread varied between 99,175 and 34,175 km2 and abundance varied from 88,100 to 4,189 beetles/km2.These findings provide an estimate of the spread patterns of dung beetles. The model can be used to guide future dung beetle release programmes in Australia and elsewhere. [ABSTRACT FROM AUTHOR]

Current methods for identifying resource preferences in dung beetles are based on above‐ground trials. Although useful, these methods do not directly investigate resource provisioning of offspring below ground, missing an important part of dung beetle ecology.We tested the potential for UV‐fluorescent and non‐fluorescent coloured glitters to be used as markers for tracing the origin of dung incorporated into brood balls (dung shaped by parental beetles enclosing an egg), and so aid in a more complete understanding of resource use in dung beetles. We tested the effect of glitter addition on brood ball production in two species of tunnelling dung beetles, Onthophagus taurus and Euoniticellus fulvus.There was no effect of glitter addition on brood ball production during no‐choice tests for each species: both species made a similar number of brood balls, regardless of glitter presence or glitter colour. In a separate choice trial, O. taurus showed no preference for dung when presented with four dung pats containing four unique glitter colours.Here we show that glitter can be used as an effective marker of individual brood ball origin in tunnelling dung beetles. This method provides a useful tool for tracking below ground resource use and larval provisioning experiments in dung beetles. [ABSTRACT FROM AUTHOR]

Examines the synthesis of a fullerene compound C60H2 compound through the hydrogenation of the C60 catalyzed by rhodium on alumina and hydrogen in deuterated benzene. Reaction conditions; Detection of C60H2 through nuclear magnetic resonance (NMR); Description of the other synthetic routes; Chromatographic testing of the derived C60H2 compound.