Effect of polymorphic colour vision for fruit detection in the spider monkey Ateles geoffroyi, and its implications for the maintenance of polymorphic colour vision in platyrrhine monkeys

Most platyrrhine monkeys have an X-linked tri-allelic polymorphism for medium and long wavelength (M/L) sensitive cone photopigments. These pigments' sensitivity maxima (λmax) range from 535 to 562 nm. All animals also have an autosomally coded short-wavelength-sensitive (S) cone pigment. In populations with three M/L alleles there are six different colour vision phenotypes. Heterozygous females have trichromatic colour vision, while males and homozygous females are dichromats. The selective basis for this polymorphism is not understood, but is probably affected by the costs and benefits of trichromatic compared to dichromatic colour vision. For example, it has been suggested that trichromats are better equipped than dichromats to detect fruit against a leaf background. To investigate this possibility, we modeled fruit detection by various colour vision phenotypes present in the frugivorous spider monkey, Ateles geoffroyi. Our study population is thought to have three M/L alleles with cone pigment λmax values close to 535, 550 and 562 nm. The model predicted that all trichromat phenotypes had an advantage over dichromats, and the 535/562 nm phenotype was best; however, the model predicted that dichromats could detect all of the fruit species consumed by spider monkeys. We conclude that the heterozygote advantage experienced by females may be the most plausible explanation for the maintenance of this polymorphism in A. geoffroyi. Nevertheless, more studies need to evaluate social foraging behaviour and the performance of different phenotypes of other New World monkeys to determine if this is a global explanation for this phenomena or more specific to A. geofforyi

Book Review Roundtable: Alexander Cooley’s Great Games, Local Rules: The New Great Power Contest in Central Asia

In this book review roundtable, seven experts discuss Alexander Cooley’s Great Games, Local Rules: The New Great Power Contest in Central Asia, followed by a response essay from the author

Flower consumption, ambient temperature and rainfall modulate drinking behavior in a folivorous-frugivorous arboreal mammal

Water is vital for the survival of any species because of its key role in most physiological processes. However, little is known about the non-food-related water sources exploited by arboreal mammals, the seasonality of their drinking behavior and its potential drivers, including diet composition, temperature, and rainfall. We investigated this subject in 14 wild groups of brown howler monkeys (Alouatta guariba clamitans) inhabiting small, medium, and large Atlantic Forest fragments in southern Brazil. We found a wide variation in the mean rate of drinking among groups (range = 0–16 records/day). Streams (44% of 1,258 records) and treeholes (26%) were the major types of water sources, followed by bromeliads in the canopy (16%), pools (11%), and rivers (3%). The type of source influenced whether howlers used a hand to access the water or not. Drinking tended to be evenly distributed throughout the year, except for a slightly lower number of records in the spring than in the other seasons, but it was unevenly distributed during the day. It increased in the afternoon in all groups, particularly during temperature peaks around 15:00 and 17:00. We found via generalized linear mixed modelling that the daily frequency of drinking was mainly influenced negatively by flower consumption and positively by weekly rainfall and ambient temperature, whereas fragment size and the consumption of fruit and leaves played negligible roles. Overall, we confirm the importance of preformed water in flowers to satisfy the howler’s water needs, whereas the influence of the climatic variables is compatible with the ‘thermoregulation/dehydration-avoiding hypothesis’. In sum, we found that irrespective of habitat characteristics, brown howlers seem to seek a positive water balance by complementing the water present in the diet with drinking water, even when it is associated with a high predation risk in terrestrial sources.Coordinación de la formación del personal de nivel superior/[2755/2010]/CAPES/BrasilNational Council for scientific and Technological Development/[303306/2013-0]/CNPq/BrasilNational Council for scientific and Technological Development/[304475/2018-1]/CNPq/BrasilNational Council for scientific and Technological Development/[140641/2016-5]/CNPq/BrasilUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Book Review Roundtable: Kathryn E. Stoner’s Russia Resurrected: Its Power and Purpose in a New Global Order and James Reilly’s Orchestration: China’s Economic Statecraft Across Asia and Europe

This double book review roundtable examines the drivers and international influence of Russia and China. It features Kathryn Stoner’s Russia Resurrected: Its Power and Purpose in a New Global Order and James Reilly’s Orchestration: China’s Economic Statecraft Across Asia and Europe

Acute changes in carotid-femoral pulse-wave velocity are tracked by heart-femoral-pulse-wave velocity

Background: Carotid-femoral pulse-wave velocity (cfPWV) is the reference standard measure of central arterial stiffness. However, it requires assessment of the carotid artery, which is technically challenging, and subject-level factors, including carotid artery plaque, may confound measurements. A promising alternative that overcomes these limitations is heart-femoral PWV (hfPWV), but it is not known to what extent changes in cfPWV and hfPWV are associated. Objectives: To determine, (1) the strength of the association between hfPWV and cfPWV; and (2) whether change in hfPWV is associated with change in cfPWV when central arterial stiffness is perturbed. Methods: Twenty young, healthy adults (24.0 [SD: 3.1] years, 45% female) were recruited. hfPWV and cfPWV were determined using Doppler ultrasound at baseline and following a mechanical perturbation in arterial stiffness (120mmHg thigh occlusion). Agreement between the two measurements was determined using mixed-effects regression models and Bland-Altman analysis. Results: There was, (1) strong (ICC >0.7) agreement between hfPWV and cfPWV (ICC= 0.82, 95%CI: 0.69,0.90), and, (2) very strong (ICC >0.9) agreement between change in hfPWV and cfPWV (ICC = 0.92, 95%CI: 0.86,0.96). cfPWV was significantly greater than hfPWV at baseline and during thigh occlusion (both P <0.001). Inspection of the Bland-Altman plot, comparing cfPWV and corrected hfPWV, revealed no measurement magnitude bias. Discussion: The current findings indicate that hfPWV and cfPWV are strongly associated, and that change in cfPWV is very strongly associated with change in hfPWV. hfPWV may be a simple alternative to cfPWV in the identification of cardiovascular risk in clinical and epidemiological settings

Factors affecting nectar sugar composition in chiropterophilic plants

AbstractMost pollinators prefer the sugars present in the nectar they consume, so it has been hypothesized that they have molded nectar trait evolution. However, nectar-feeding bats do not exhibit preferences for the sugars present in their diet. We analyzed the role that biochemical and ecological factors could play in shaping the nectar traits of chiropterophilic plants. We studied nectar traits and flower production in 49 plant species. We evaluated the relationship between nectar concentration and sugar composition using phylogenetically independent contrasts and if nectar traits were related to flower production using a Manova. We found that 42 species produced high hexoses nectars, and 7 species produced sucrose rich nectars. Phylogenetically independent contrasts showed that nectar concentration was negatively related to glucose content, positively related to fructose content, and was not related to sucrose content. A negative relationship was found from glucose and fructose contents to sucrose content, and glucose content was negatively related to fructose content. Finally, we did not found any relationship between nectar traits and the plants’ flowering strategies. We conclude that bat physiology and the relative low evolutionary time of the interaction between plants and bats may determine the lack of pattern in the nectar characteristics of chiropterophilic plants

Relationship between Spatial Working Memory Performance and Diet Specialization in Two Sympatric Nectar Bats

Behavioural ecologists increasingly recognise spatial memory as one the most influential cognitive traits involved in evolutionary processes. In particular, spatial working memory (SWM), i.e. the ability of animals to store temporarily useful information for current foraging tasks, determines the foraging efficiency of individuals. As a consequence, SWM also has the potential to influence competitive abilities and to affect patterns of sympatric occurrence among closely related species. The present study aims at comparing the efficiency of SWM between generalist (Glossophaga soricina) and specialist (Leptonycteris yerbabuenae) nectarivorous bats at flowering patches. The two species differ in diet – the generalist diet including seasonally fruits and insects with nectar and pollen while the specialist diet is dominated by nectar and pollen yearlong – and in some morphological traits – the specialist being heavier and with proportionally longer rostrum than the generalist. These bats are found sympatrically within part of their range in the Neotropics. We habituated captive individuals to feed on artificial flower patches and we used infrared video recordings to monitor their ability to remember and avoid the spatial location of flowers they emptied in previous visits in the course of 15-min foraging sequences. Experiments revealed that both species rely on SWM as their foraging success attained significantly greater values than random expectations. However, the nectar specialist L. yerbabuenae was significantly more efficient at extracting nectar (+28% in foraging success), and sustained longer foraging bouts (+27% in length of efficient foraging sequences) than the generalist G. soricina. These contrasting SWM performances are discussed in relation to diet specialization and other life history traits

Validity and reliability of lower-limb pulse-wave velocity assessments using an oscillometric technique

There is a growing interest in the deleterious effects of sedentary behaviour on lower-limb arterial health. To permit further investigation, including in larger epidemiological studies, there is a need to identify lower-limb arterial health assessment tools that are valid and reliable, yet simple to administer. Purpose: This study sought to determine the validity and between-day reliability of femoral-ankle pulse-wave velocity (faPWV) measures obtained using an oscillometric-based device (SphygmocCor XCEL) in supine and seated positions. Doppler ultrasound (US) was used as the criterion. Methods: A total of 47 healthy adults were recruited for validity (n=32) and reliability (n=15) analyses. Validity was determined by measuring faPWV in seated and supine positions using the XCEL and US devices, in a randomised order. Between-day reliability was determined by measuring seated and supine faPWV using the XCEL on 3 different mornings, separated by a maximum of 7 days. Results: The validity criteria (absolute standard error of estimate [aSEE] <1.0 m/s) was met in the supine (aSEE = 0.8 m/s, 95% CI: 0.4-1.0), but not the seated (aSEE = 1.2 m/s, 95 % CI: 1.1, 1.2) position. Intras-class correlation coefficient estimates revealed the XCEL demonstrated good reliability in the supine position (ICC=0.83, 95% CI: 0.65, 0.93), but poor reliability in the seated position (ICC = 0.29, 95% CI: 0.23, 0.63). Conclusions: The oscillometric XCEL device can be used to determine lower-limb PWV with acceptable validity and reliability in the conventionally recommended supine position, but not the seated position

Sleeping-tree fidelity of the spider monkey shapes community-level seed-rain patterns in continuous and fragmented rain forests

Repeated use of sleeping trees (STs) by frugivores promotes the deposition and aggregation of copious amounts of seed, thus having key implications for seed dispersal and forest regeneration. Seed-rain patterns produced by this behaviour likely depend on the frequency of use of these sites, yet this hypothesis has been poorly tested. We evaluated community-level seed-rain patterns produced by the spider monkey (Ateles geoffroyi) over 13 mo in latrines located beneath 60 STs in the Lacandona rain forest, Mexico. Because this primate is increasingly ‘forced’ to inhabit fragmented landscapes, we tested whether sleeping-tree fidelity (STF) differed among sites and between continuous and fragmented forests. We also tested whether seed-rain patterns were associated with STF within each site and forest type. STF was highly variable among STs (average = 7 mo, range = 1–12 mo), but did not differ among study sites or forest types. STF was positively associated with seed abundance, species diversity and species turnover. Nevertheless, STF tended to be negatively related to seed community evenness. These results are likely due to the most frequently used STs being in areas with greater food density. Our results demonstrate that site fidelity shapes community-level seed-rain patterns and thus has key ecological implications

Effects of acute prolonged sitting on cerebral perfusion and executive function in young adults: a randomized cross-over trial

Exposure to acute prolonged sitting reportedly leads to decreased cerebral blood flow. However, it is unclear whether this exposure translates to decreased cerebral perfusion and executive function, or whether simple strategies to break-up sitting can maintain cerebral perfusion and executive function. This study sought to answer two questions: in young, healthy adults (i) does prolonged (3 h) sitting lead to decreased cerebral perfusion and executive function? and (ii) does breaking-up prolonged sitting, using intermittent calf raise exercises, prevent changes in cerebral perfusion and executive function? Twenty young, healthy participants (21.7 [2.5] y, 70% F, 25.5 [6.1] kg/m2) were randomized to: 3 h sitting with 10 calf raises every 10 min (CALF), and 3 h sitting without calf intermittent calf raises (CON). Prefrontal cortex perfusion was assessed using near-infrared spectroscopy to monitor total hemoglobin (tHB) concentration and tissue saturation index (TSI, oxygenated hemoglobin). Executive function was assessed using the Stroop Word and Color Tasks. Following 3 h sitting, tHb was significantly lower in CALF vs. CON (-2.1 μM, 95% CI: -3.1, -1.1). TSI was not significantly different between conditions (P = .667). Word (1.6 ms, 95% CI: 0.7, 2.5) and Color (1.3 ms, 95% CI: -0.2, 2.8) completion times were longer (worse) for CALF compared to CON. In conclusion, calf raises decreased both cerebral perfusion and executive function. Simple strategies, such as fidgeting or calf raises, which have been reported to preserve vascular function in the legs, appear not to be sufficient enough to benefit cerebral perfusion or executive function