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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.lmot.2008.11.002 Byline: Michael J. Beran (a), Chasity L. Ratliff (b), Theodore A. Evans (a) Keywords: Chimpanzees; Pan troglodytes; Natural choice; Selective value effect; Foraging; Decision-making Abstract: In three experiments, four chimpanzees made choices between two visible food options to assess the validity of the selective value effect (the assignment of value to only the most preferred type of food presented in a comparison). In Experiment 1, we established that all chimpanzees preferred single banana pieces to single apple pieces before presenting the critical test. In this test two chimpanzees preferred a mix of one banana piece and one apple piece to a single banana piece when both banana pieces were approximately the same size, but two chimpanzees were indifferent between the two options, exhibiting the selective value effect. In Experiment 2, when the banana pieces in both options were more closely equated in size, the chimpanzees were biased to choose the single banana piece over the mixed array even though this was the smaller total amount of food. However, in Experiment 3, when we introduced longer intervals between each trial, the chimpanzees preferred the mixed set and thus the larger total amount of food. The results demonstrate that only some chimpanzees exhibit the choice pattern indicative of the selective value effect, and they do so only when item size is not carefully controlled and trials are presented quickly in succession. Thus, the behavior pattern originally labeled the selective value effect may actually be explained by a combination of chimpanzees' sensitivity to small differences in preferred food amount and chimpanzees tendency to avoid less preferred foods that would delay the acquisition of further preferred food items. Author Affiliation: (a) Language Research Center, Georgia State University, University Plaza, Atlanta, GA 30302, USA (b) Southeast Missouri State University, Cape Girardeau, MO, USA Article History: Received 2 September 2008; Revised 25 October 2008

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2007.10.035 Byline: Michael J. Beran, Theodore A. Evans, Emily H. Harris Abstract: 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. Author Affiliation: Language Research Center, Georgia State University, U.S.A. Article History: Received 16 May 2007; Revised 14 July 2007; Accepted 29 October 2007 Article Note: (miscellaneous) MS. number: A10772R

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.lmot.2007.02.001 Byline: Theodore A. Evans Keywords: Self-control; Delay of gratification; Delay; Effort; Rhesus monkey; Macaca mulatta 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. Author Affiliation: Language Research Center, Georgia State University, 3401 Panthersville Road, Decatur, GA 30034, USA Article History: Received 24 October 2006; Revised 7 February 2007 Article Note: (footnote) [star] This research was supported by grant HD-38051 from the National Institute of Child Health and Human Development. All applicable institutional rules and regulations regarding animal care and use have been followed in the care and testing of the macaques. The experiments complied with all laws of the United States of America. I thank Michael Beran for thoughtful discussion of methodological issues relevant to this study and both Michael Beran and Emily Klein for their comments on an earlier version of this manuscript.

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]

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]

• Natural regeneration of peatswamp forest on degraded peatlands is driven by distance to forest, mammal and bird dispersal. • Regeneration occurred in clusters of young trees at distances up to 2 km from the forest. • Forest burnt in 1997 had higher species diversity and trees per plot than intact forest. • Natural regeneration could restore degraded peatlands surrounding remnant forest patches up to 500 m from natural forest. Restoration of peat swamp forest (PSF) on degraded Southeast Asian peatlands could reduce global carbon emissions and biodiversity loss. However, multiple ecological barriers are believed to hinder natural regeneration of native trees on degraded peatland and make restoration expensive. We evaluated if natural PSF regeneration occurs and what factors may influence it on eight different land use and land cover (LULC) classes with different types of disturbance, including drainage and fire, in a retired Acacia crassicarpa Benth. (Acacia) plantation landscape. The study involved 42 plots inside five PSF LULCs – intact, logged, burnt (1997, 2015), remnant and 212 plots at distances up to 2 km from the PSF edge in three Acacia plantation LULCs – unharvested, harvested, and burnt. The number of species per plot were similar between intact PSF (25 ± 6 (SD) per 20 m × 10 m plot), logged forest (30 ± 6) and 1997 burnt forest (30 ± 13) but lower in 2015 burnt forest (11 ± 10) and remnant forest (18 ± 11). Regeneration away from the PSF across all degraded LULCs varied from fern dominated areas with no regeneration to clusters with high stem densities. The plantation LULCs, unharvested (94 species) and harvested Acacia (71 species), had similar overall species diversity after 3–4 years of regeneration to the intact and logged PSF (90 species). In unharvested Acacia , total species diversity, species per plot and stem density decreased with distance from forest edge (1–300 m – 87 species; 9 ± 6 (SD) species per 20 m × 10 m plot; 1,056 stems/ha; 301–500 m – 33; 5 ± 2; 511 and >500 m – 38; 6 ± 3; 683). In harvested Acacia , there was low plot species diversity irrespective of distance from the forest (1–300 m – 51; 4 ± 2; 578; 301–500 m – 17; 4 ± 2; 1,100; >500 m – 48; 4 ± 2; 780). Factors which may influence regeneration differed between different LULCs, but there was a clear influence of distance from forest edge and dispersal mechanism – i.e. whether a tree was bird or mammal dispersed and the interaction between these two factors. While our study suggests that if not further disturbed by logging, drainage and/or fire, degraded PSF could regenerate naturally to a similar species diversity as intact PSF, the lower levels of natural regeneration further away from the forest may warrant selective planting of species which do not disperse over long distances. More study is needed on the factors facilitating natural regeneration, whether it leads to restoration of PSF ecosystem functioning and the role of Acacia as a potential regeneration catalyst. [ABSTRACT FROM AUTHOR]

Abstract: Cables sheathed with medium density polyethylene or polyamide were exposed together with highly palatable bait wood to termite faunas in south-eastern and northern Australia, Thailand and southern USA using three methods: below-ground exposure, samples buried horizontally at a depth of 15–30 cm; graveyard method, samples inserted vertically 25 cm deep into the ground; ground contact method, samples placed horizontally on the ground surface, covered with soil and a plastic sheet. Samples were inspected for damage and bait wood replaced annually for six years. No polyamide sample was attacked. Damage to polyethylene was most severe at the Australian sites (across all methods) and in the graveyard method (across all sites), although in Australia in the below-ground method samples experienced greatest damage. Exposing samples together with bait wood within containers for one year, and replenishing bait wood up to three times, i.e. an ‘accelerated’ test method, compared to the standard procedure of providing new bait wood only once a year, resulted in only very limited damage to cables at Asian sites (Macrotermitinae, Coptotermes spp., Malaysia; Coptotermes formosanus, Japan), matching the earlier results for Thailand. But 73% of samples were destroyed by Coptotermes acinaciformis in northern Australia. The Australian termite fauna responds more aggressively to plastic samples than major pest species of termite elsewhere. [Copyright &y& Elsevier]

Abstract: In contrast to the majority of the Order, the dampwood termites of the family Termopsidae found in colder regions can experience frost and snow, either in cool temperate areas at high latitudes (45°), or alpine areas at high elevations (>1000m). This suggests that dampwood termites are adapted to cold climates. We investigated this hypothesis in two dampwood termites, Porotermes adamsoni Froggatt and Stolotermes victoriensis Hill. We measured nest temperatures and atmospheric temperatures of their alpine habitat during winter, and measured survival and recovery at subzero temperatures. We also determined the minimum temperature at which these species remain active and the LT50 values. We used a novel gas chromatographic strategy to examine eight metabolites from individuals of both species collected in winter and summer to identify possible cryoprotectants. Both P. adamsoni and S. victoriensis had significantly higher levels of trehalose, a known cryoprotectant, in winter than in summer; in addition S. victoriensis also had higher levels of unsaturated fatty acid ligands in winter than in summer, consistent with patterns observed for cold adaptation in other organisms. These results are the first to reveal that dampwood termites are adapted to cold climates and use trehalose and unsaturated lipids as cryoprotectants. [Copyright &y& Elsevier]

Termites sense tiny substrate-borne vibrations through subgenual organs (SGOs) located within their legs' tibiae. Little is known about the SGOs' structure and physical properties. We applied high-resolution (voxel size 0.45 μm) micro-computed tomography (μCT) to Australian termites, Coptotermes lacteus and Nasutitermes exitiosus (Hill) to test two staining techniques. We compared the effectiveness of a single stain of Lugol's iodine solution (LS) to LS followed by Phosphotungstic acid (PTA) solutions (1% and 2%). We then present results of a soldier of Nasutitermes exitiosus combining μCT with LS + 2%PTS stains and scanning electron microscopy to exemplify the visualisation of their SGOs. The termite's SGO due to its approximately oval shape was shown to have a maximum diameter of 60 μm and a minimum of 48 μm, covering 60 ± 4% of the leg's cross-section and 90.4 ± 5% of the residual haemolymph channel. Additionally, the leg and residual haemolymph channel cross-sectional area decreased around the SGO by 33% and 73%, respectively. We hypothesise that this change in cross-sectional area amplifies the vibrations for the SGO. Since SGOs are directly connected to the cuticle, their mechanical properties and the geometric details identified here may enable new approaches to determine how termites sense micro-vibrations. [ABSTRACT FROM AUTHOR]

Abstract: Choosing to wait for a better outcome (delay choice) and sustaining the delay prior to that outcome (delay maintenance) are both prerequisites for successful self-control in intertemporal choices. However, most existing experimental methods test these skills in isolation from each other, and no significant correlation has been observed in performance across these tasks. In this study we introduce a new paradigm, the hybrid delay task, which combines an initial delay choice with a subsequent delay maintenance stage. This allows testing how often choosing to wait is paired with the actual ability to do so. We tested 18 capuchin monkeys (Cebus apella) from two laboratories in various conditions, and we found that subjects frequently chose the delayed reward but then failed to wait for it, due to poor delay maintenance. However, performance improved with experience and different behavioral responses for error correction were evident. These findings have far reaching implications: if such a high error rate was observed also in other species (possibly including Homo sapiens), this may indicate that delay choice tasks that make use of salient, prepotent stimuli do not reliably assess generalized self-control, insofar as choosing to wait does not entail always being able to do so. [Copyright &y& Elsevier]

• Tea Bag Index is originally designed to characterise microbial-driven decomposition. • Application of Tea Bag Index in termite-rich habitats greatly reduced sample size. • Using termite-exclusion barrier preserved full sample size in termite-rich habitats. • We also propose extending the Tea Bag Index to incorporate termite-driven mass loss. • Extended Tea Bag Index validated – contribute to pan-tropical decomposition data. The Tea Bag Index (TBI) is a standardised and cheap method to quantify microbial-driven decomposition by measuring the mass loss of tea within tea bags. Termites are known to damage the bags to access the content, rendering the method less suitable for termite-rich ecosystems. Extension of the TBI to accommodate and incorporate the influence of termites would broaden its applicability to include termite-rich ecosystems, such as tropical forests. We extended the original TBI by applying physical and chemical termite-exclusion methods. Tea mass loss and the proportion of tea bags detected by termites in the original TBI were also recorded to infer the role of termites in litter decomposition. TBI estimates derived from the original and extended TBI were compared, benchmarked against global estimates, and validated with time-series mass loss data. Using the original TBI, we found that termites damaged up to 80 % of tea bags and consumed the recalcitrant fraction of tea in several of them, leaving only 20 % of tea bags from which TBI estimates could be retrieved. The physical termite-exclusion treatment completely eliminated termite-infringement, thus preserving the full sample size for estimating TBI parameters. The chemical termite-exclusion treatment also successfully excluded termites, but potentially inhibited microbial decomposition and made TBI estimates unreliable. In the absence of termite-infringement, both the TBI estimates and time-series analysis revealed a low decomposition rate compared to other measurements in tropical and temperate regions. We propose an extended TBI, in which the physical termite-exclusion treatment is used to preserve the retrieval rate of TBI parameters and reliably measure microbial-driven decomposition, while the original TBI is used to incorporate the contribution of termites in driving litter mass loss. By characterising both termite- and microbial-driven decomposition, the extended TBI will provide a comprehensive understanding of decomposition and its drivers in termite-rich ecosystems, and permit global comparisons. [ABSTRACT FROM AUTHOR]