scholarly journals An interaction mechanism for the maintenance of fission–fusion dynamics under different individual densities

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8974
Author(s):  
David Bierbach ◽  
Stefan Krause ◽  
Pawel Romanczuk ◽  
Juliane Lukas ◽  
Lenin Arias-Rodriguez ◽  
...  
Keyword(s):  
Interaction Mechanism ◽  
Social Contact ◽  
Social Partner ◽  
Slight Reduction ◽  
Low Density ◽  
Social Time ◽  
Poecilia Mexicana ◽  
Group A ◽  
Random Walk Simulation ◽  
High Consistency

Animals often show high consistency in their social organisation despite facing changing environmental conditions. Especially in shoaling fish, fission–fusion dynamics that describe for which periods individuals are solitary or social have been found to remain unaltered even when density changed. This compensatory ability is assumed to be an adaptation towards constant predation pressure, but the mechanism through which individuals can actively compensate for density changes is yet unknown. The aim of the current study is to identify behavioural patterns that enable this active compensation. We compared the fission–fusion dynamics of two populations of the live-bearing Atlantic molly (Poecilia mexicana) that live in adjacent habitats with very different predator regimes: cave mollies that inhabit a low-predation environment inside a sulfidic cave with a low density of predatory water bugs (Belostoma sp.), and mollies that live directly outside the cave (henceforth called “surface” mollies) in a high-predation environment. We analysed their fission–fusion dynamics under two different fish densities of 12 and 6 fish per 0.36 m2. As expected, surface mollies spent more time being social than cave mollies, and this difference in social time was a result of surface mollies being less likely to discontinue social contact (once they had a social partner) and being more likely to resume social contact (once alone) than cave mollies. Interestingly, surface mollies were also less likely to switch among social partners than cave mollies. A random walk simulation predicted each population to show reduced social encounters in the low density treatment. While cave mollies largely followed this prediction, surface mollies maintained their interaction probabilities even at low density. Surface mollies achieved this by a reduction in the size of a convex polygon formed by the group as density decreased. This may allow them to largely maintain their fission–fusion dynamics while still being able to visit large parts of the available area as a group. A slight reduction (21%) in the area visited at low densities was also observed but insufficient to explain how the fish maintained their fission–fusion dynamics. Finally, we discuss potential movement rules that could account for the reduction of polygon size and test their performance.

scholarly journals Social networks in the presence and absence of visual cues

2018 ◽  
Author(s):  
David Bierbach ◽  
Stefan Krause ◽  
Pawel Romanczuk ◽  
Juliane Lukas ◽  
Lenin Arias-Rodriguez ◽  
...  
Keyword(s):  
Visual Cues ◽  
Social Dynamics ◽  
Social Contact ◽  
Mechanistic Explanation ◽  
Social Partner ◽  
Low Density ◽  
Network Analyses ◽  
Poecilia Mexicana ◽  
The Social ◽  
Two Populations

AbstractWe compared the social dynamics of two populations of the live-bearing Atlantic molly (Poecilia mexicana) that live in adjacent habitats with very different predator regimes: cave mollies that inhabit a low-predation environment inside a sulfidic cave with a low density of predatory water bugs (Belostoma sp.), and mollies that live directly outside the cave (henceforth called “surface” mollies) in a high-predation environment with a high density of fish-eating birds. We filmed the social interactions of marked fish in both environments and analysed their social network dynamics using a Markov model under two different fish densities of 12 and 6 fish per 0.36 m2. As expected, surface mollies spent overall much more time social than cave mollies. This difference in overall social time was a result of surface mollies being less likely to discontinue social contact (once they had a social partner) and being more likely to resume social contact (once alone) than cave mollies. Interestingly surface mollies were also less likely to leave a current social partner than cave mollies. At low density, mollies (in both environments) were expected to show reduced social encounters which should dramatically change their social dynamics. Surface mollies, however, displayed an ability to maintain their social dynamics at low density (primarily by reducing the convex polygon spanned by the group) which was not observed in cave mollies. Despite the fact that we only compared two populations, our data provide a mechanistic explanation for density compensations of social dynamics that have also been observed in other fish species and give an example of how comparisons between the social dynamics of different populations can be made that go beyond conventional network analyses.

To Study Thyroid Function and Lipid Profile Levels in Chronic Kidney Disease Patients in a Tertiary Care Hospital of North India

2021 ◽  
Vol 8 (32) ◽  
pp. 2980-2987
Author(s):  
Navjot Kaur Layal ◽  
Tejinder Sikri ◽  
Jaskiran Kaur ◽  
Jasmine Kaur ◽  
Hardeep Singh Deep
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Lipid Profile ◽  
Thyroid Dysfunction ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Care Hospital ◽  
Low T3 ◽  
Group A

BACKGROUND Chronic kidney disease (CKD) includes a spectrum of different pathophysiology processes associated with abnormal kidney function, and a progressive decline in GFR. Progression of CKD is associated with having a number of complications, including thyroid dysfunction, dyslipidaemia, and cardiovascular diseases. METHODS The present study was conducted among 60 CKD patients (cases) and 60 healthy controls to compare their thyroid and lipid profile, who attended the Department of Medicine in SGRDIMSR, Sri Amritsar from January 2019 to December 2020.These 60 CKD patients were grouped as group A. Group A was further divided into various stages as per KIDGO staging according to GFR. 60 healthy individuals were taken as controls and were kept as Group B. Demographic features (age and sex) and medical history of diabetes mellitus, hypertension were noted and blood samples (5mL) were analysed for blood urea, serum creatinine, free triiodothyronine (T3), free thyroxine (T4), thyroid stimulating hormone (TSH), total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low density lipoprotein (VLDL) and triglycerides. RESULTS Thyroid dysfunction was observed in patients of CKD, the most common being overt hypothyroidism (56.6 %) followed by subclinical hypothyroidism (16.6 %), low T3 (15 %), and hyperthyroidism (1.6 %). Hypercholesterolemia, low HDL, elevated LDL, VLDL and triglyceride levels were observed in 74.9 %, 85.0 %, 38.3 %, 41.6 % and 76.6 % patients, respectively. Patients with CKD with 5 had significantly higher risk of having thyroid dysfunction and dyslipidaemia as compared to patients with stage 3 and 4. CONCLUSIONS Thyroid dysfunction and dyslipidaemia were common in patients with CKD. Prevalence of hypothyroidism, dyslipidaemia increases with progression of CKD. Hence early detection of thyroid dysfunction and dyslipidaemia is imperative to improve mortality and morbidity of CKD patients. KEYWORDS Chronic Kidney Disease, Dyslipidaemia, Thyroid Dysfunction

scholarly journals Effect of Whole Quail (Coturnix japonica) Egg Consumption on some Reproductive Parameters and Lipid Profile of Male Albino Rat (Rattus norvegicus)

2017 ◽  
Vol 9 (3) ◽  
pp. 315-320 ◽  
Author(s):  
Chidozie N. OKOYE ◽  
Samuel O. EKERE ◽  
Onyinyechukwu A. AGINA ◽  
Ikechukwu J. UDEANI ◽  
Chukwunonso K. EZEASOR
Keyword(s):  
Lipid Profile ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Control Group ◽  
Low Density ◽  
Epididymal Sperm ◽  
Treatment Groups ◽  
Egg Consumption ◽  
Group A ◽  
The Mean

The present study evaluated the effect of whole egg consumption on the liver, testes, cauda epididymal sperm reserve and lipid profile of male rats. These evaluations were carried out on adult twenty (20) male albino rats, which were randomly selected into four groups of 5 rats each, designated groups A, B, C and D. Group A was the control group and received only equivalent volume of distilled water, while groups B, C and D received 0.25mg/kg, 0.5mg/kg; and 1.0mg/kg body weight of the quail egg respectively. Standard procedures were carried out in the tissue processing, cauda epididymal sperm reserve and in lipid profile determinations. On days 35 and 49, the mean serum total cholesterol value of group D was significantly lower than that of the control group. On day 35, the mean serum low density lipoprotein and high density lipoprotein (LDL and HDL cholesterol) values of all the treatment groups were significantly lower and higher than that of the control group, respectively. However, on days 49 and 63, the mean serum very low density lipoprotein (VLDL cholesterol) and triglyceride values of all the treatment groups were significantly higher than that of the control group. A significant increase in cadual epididymal sperm count (CESR) was recorded on day 63 at the mid and high doses. No obvious pathological lesions were observed in the histomorphology of the testes and liver when compared to the control. Therefore, whole quail egg consumption caused an increase in serum triglyceride and very low density lipoprotein concentration, and also improved fertility. In other words, prolonged consumption of quail egg should be done with caution as it may predispose one to cardiovascular disease.

scholarly journals “A Comparative Study of Efficacy of Atorvastatin Alone and Atorvastatin with Omega-3 Fatty Acids Combination in Patients with Hyperlipidaemia Attending Tertiary Care Hospital”

2021 ◽  
pp. 482-490
Author(s):  
C. Srinivasa ◽  
K. La Kshminarayan ◽  
V. Srinivas ◽  
B. V. S. Chandrasekhar
Keyword(s):  
Fatty Acids ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Hdl Cholesterol ◽  
Low Density ◽  
Care Hospital ◽  
Omega 3 Fatty Acids ◽  
Omega 3 ◽  
Group A ◽  
Group B

Background: Current treatment with statins has become an integral part of vascular diseases but monotherapy has a significant residual event rate. Due to particularly one of the factor associated with atherogenic lipid phenotype that is characterized by a low high-density lipoprotein (HDL) cholesterol and increase in non-HDL cholesterol like Low-Density Lipoprotein (LDL). Omega-3 Fatty acids have demonstrated a preventiverole in primary and, particularly secondary cardiovascular diseases.  Hence this study was planned to compare the efficacy of Atorvastatin alone with Atorvastatin and Omega-3 fatty acids in treatment in hyperlipidaemia patients. Methods: The study was comparative, randomized, and prospective and open labeled conducted in MI patients. A total of 100 patients were selected based on inclusion and exclusion criteria. They were divided randomly into two Groups (Group–A and Group-B). Group-A was given Atorvastatin 10mg/day and Group-B was given Atorvastatin 10mg/day and Omega-3 fatty acids 600mg/day for 6 months. Follow up was done every month and efficacy was measured by assessing the lipoprotein levels in serum. Results: The results were compared before treatment and after 6 months treatment.The levels were significantly decreased Total Cholesterol (TC), LDL, Low-Density Lipoprotein (VLDL), Triglycerides (TG) and HDL levels were increased in Group–A and Group-B. When these results compared between two Groups the HDL levels were increased also it shown high significance (<0.001) but there were no significance changes in other cholesterol levels. Conclusion: The present study results showed that Atorvastatin and Omega-3 fatty acids treatment was more effective than Atorvastatin alone treatment in improving HDL-C levels from base line and it may have a additive effect in major coronary artery diseases.

scholarly journals Study of serum lipid profile and magnesium in preeclampsia

2019 ◽  
Vol 8 (4) ◽  
pp. 1445
Author(s):  
Hymavathi K. Reddy ◽  
Vineela P. ◽  
Bhargavi M. Chowdary
Keyword(s):  
Lipid Profile ◽  
Serum Lipid ◽  
Serum Magnesium ◽  
Low Density Lipoprotein ◽  
Tertiary Care ◽  
Density Lipoprotein ◽  
Serum Lipid Profile ◽  
Low Density ◽  
Group A ◽  
Group B

Background: A comparative study of serum lipid profile and magnesium levels in normal pregnancy versus preeclampsia (PE).Methods: A prospective study done for 2 years (October 2014 to October 2016) in the Department of Obstetrics and Gynecology, Narayana medical college and hospital, a tertiary care centre, Nellore, Andhra Pradesh, India. A sample size of 200 pregnant women, recruited and divided into group A and B. group A being women with PE and group B is normal pregnant women.A10ml of venous blood was collected in the fasting state and serum collected from clotted blood to measure lipid profile, magnesium, Apo lipoprotein A-I and Apo lipoprotein B 100.Serum Lipid profile  measured by enzymatic method using commercially available kit Human (GmbH Germany) using humastar 600 chemistry analyzer (Human GmbH Germany). Serum magnesium measured by dye binding method using commercially available kit Human (GmbH Germany) using Humastar 600 chemistry analyzer (Human GmbH Germany). Serum ApoA-I and ApoB were measured by immune-turbidometry using commercial kits from Spinreact Spain. Urine albumin done by dipstick method.Results: Serum total cholesterol (TC), Triglyceride (TG), low density lipoprotein (LDL), very low-density lipoprotein (VLDL), Apo lipoprotein B 100 (Apo B100) were high and serum Magnesium, high density lipoprotein (HDL) and Apo lipoprotein A1(Apo A1) were low in the study group (group A) compared to controls (group B).Conclusions: Abnormal lipid profile (low HDL and increased TG concentration) and serum hypomagnesaemia may be contributing etiologies of preeclampsia, having good predictive value as a screening procedure for PE in high risk pregnant population.

Investigation on Improvement of Flexural Behavior of Low-Density Cellular Concrete through Fiber Reinforcement for Non-Structural Applications

2019 ◽  
Vol 2673 (10) ◽  
pp. 641-651
Author(s):  
Arman Abdigaliyev ◽  
Jiong Hu
Keyword(s):  
Mechanical Properties ◽  
Lightweight Concrete ◽  
Construction Material ◽  
Flexural Behavior ◽  
Unit Weight ◽  
Slight Reduction ◽  
Low Density ◽  
Hybrid Fibers ◽  
Structural Applications ◽  
Cellular Concrete

During the last decades, cellular lightweight concrete (CLC), or foamed concrete, has been experiencing greater interest in geotechnical, structural, and non-structural applications. The low density and high flowability makes it a favorable construction material in relation to handling, placing, and construction costs. However, the applications of low-density cellular concrete (LDCC), the category of CLC with a unit weight less than 50 pounds per cubic foot (801 kg/m3) and generally without fine aggregates, are limited mostly to backfill applications in geotechnical engineering. The main reason lies in the brittleness of the material and low to zero resistance to flexural loads. Fiber-reinforced LDCC may be a reasonable solution to improve mechanical properties and expand the application range of the material. This study investigated the effects of adding polypropylene and hybrid fibers on physical and mechanical properties of LDCC and the feasibility of expanding LDCC utilization to non-structural applications. Results showed that although there is a slight reduction of flowability and compressive strength, the flexural behavior of LDCC can be significantly improved with the incorporation of fibers. The flexural strength and flexural toughness of LDCC was found to increase from 26.8 pounds per square inch (psi) (0.18 MPa) to 217.5 psi (1.48 MPa), and from 5.67 lb-in. (0.64 kN-mm) to 292 lb-in. (33.0 kN-mm) respectively at a 1.0% addition rate of a fibrillated polypropylene fiber selected in this study, which makes it a feasible material for non-structural applications.

Group A Pak Proteins Are Essential for HSC/P Engraftment.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2624-2624
Author(s):  
Adrienne M. Dorrance ◽  
Abel Sanchez-Aguilera ◽  
Serena De Vita ◽  
Michael D. Milsom ◽  
Jonathan Chernoff ◽  
...  
Keyword(s):  
Effector Proteins ◽  
Low Density ◽  
Control Vector ◽  
Cells In Culture ◽  
Antibody Staining ◽  
Rac Gtpases ◽  
Flow Sorting ◽  
Group A ◽  
Empty Control

Abstract Abstract 2624 Rho GTPases, including Rac, integrate multiple extracellular signals and play important regulatory roles in critical hematopoietic stem and progenitor (HSC/P) functions such as cell migration, adhesion, proliferation, and survival. Conditional deletion of Rac1 in the hematopoietic cells results in defects in proliferation and engraftment while Rac2 germline deletion leads to enhanced cell death and increased HSC/P mobilization, most likely resulting from decreased adhesion via altered integrin signalling (Gu et al. Science, 2003). Although, Rac1 and Rac2 proteins have been shown to regulate distinct biological processes, simultaneous deletion of both Rac1 and Rac2 reveal overlapping functions in HSC/P survival, mobilization, engraftment, and retention (Cancelas et al. Nat. Med., 2006). Our studies now focus on indentifying potential downstream effector proteins of Rac that are important for normal HSC/P function(s). The best characterized Rac effector proteins are the Pak protein kinases, including Group A (Pak1, Pak2, and Pak3) Paks. Pak proteins not only have an intrinsic kinase activity but also regulate actin-dependent functions. Previous studies have demonstrated inhibition of Rac in HSC/P was associated with reduced phosphorylation of Pak1 (Cancelas et al. Nat. Med., 2006). However, the exact role Pak proteins play in HSC/P function(s) has yet to be elucidated. To further identify the possible role(s) of Pak proteins in hematopoiesis, freshly isolated lineage-, Sca-1+; c-Kit+ (LSK) cells from BoyJ(CD45.1)/C57Bl6J(CD45.2) F1 donor mice were transduced with retroviral vectors containing the Pak Inhibitory Domain (PID), which inhibits Group A Pak protein function, or empty vector control (Mieg3); both constructs co-express GFP. 6.0×104 GFP+ CD45.1/CD45.2 LSK cells were then isolated and co-transplanted with 5.0×105 BoyJ (CD45.1) bone marrow (BM) into lethally irradiated C57Bl/6J (CD45.2) recipients. Percent chimerism was measured from 3-weeks up to 14-weeks post BM transplant. We found that PID transduced LSK cells were incapable of contributing to recipient hematopoietic reconstitution compared to Mieg3 transduced controls at 14 weeks post-transplant (0/9 PID transduced demonstrated >1% engraftment vs 9/9 Mieg3 transduced which had >10% engraftment, p<0.05). To explore the underlying mechanism of this engraftment failure, we cultured transduced LSK in vitro for up to 12 days and compared growth of GFP+ vs GFP- cells. The growth of PID transduced LSK was essentially identical to non-transduced cells for the initial 7 days of in vitro culture. However between day 7 and day 10, the PID LSK cells displayed decreased growth kinetics (Fig. 1). The reduced growth in vitro was correlated with decreased proliferation as measured by BrdU incorporation. There was no change in cell survival, as assessed by AnnexinV staining. Furthermore, LSK cells transduced with a dominant negative Pak construct (DN-Pak), a more general inhibitor of Pak activity, showed defects in cytoskeletal rearrangements after stimulation with the HSC/P chemoattract, SDF-1α. These data suggest that Pak proteins may be critical downstream effectors of Rac GTPases and defective Pak activation may mechanistically link the role of Rac GTPases in regulation of both cytoskeletal and proliferative functions of HSC/P during engraftment. Fig. 1 Low-density mononuclear BM cells were depleted of lineage-positive (lin+) cells as described previously (Milsom et al. Blood, (2009). After antibody staining, lin–, Sca-1+, c-Kit+ (LSK) cells were isolated by flow sorting. LSK cells were prestimulated for 48 hours, after which the cells were transduced with a vector expressing PIDK or Mieg3 empty control vector. 48 hours later, % transduction was determined. Cells were then cultured in 10% IMDM + cytokines for an additional 12 days. The percentage of GFP+ cells in culture was determined at days 2, 5, 7, 10, and 12 post-transduction. Fig. 1. Low-density mononuclear BM cells were depleted of lineage-positive (lin+) cells as described previously (Milsom et al. Blood, (2009). After antibody staining, lin–, Sca-1+, c-Kit+ (LSK) cells were isolated by flow sorting. LSK cells were prestimulated for 48 hours, after which the cells were transduced with a vector expressing PIDK or Mieg3 empty control vector. 48 hours later, % transduction was determined. Cells were then cultured in 10% IMDM + cytokines for an additional 12 days. The percentage of GFP+ cells in culture was determined at days 2, 5, 7, 10, and 12 post-transduction. Disclosure: Sanchez-Aguilera: Children's Hospital Boston: Employment.

scholarly journals Social Contact Reinforces Cocaine Self-Administration in Young Adult Male Rats: The Role of Social Reinforcement in Vulnerability to Drug Use

2021 ◽  
Vol 15 ◽  
Author(s):  
Mark A. Smith ◽  
Hannah S. Cha ◽  
Annie K. Griffith ◽  
Jessica L. Sharp
Keyword(s):  
Young Adult ◽  
Drug Use ◽  
Guillotine Door ◽  
Social Group ◽  
Social Contact ◽  
Male Rats ◽  
Social Partner ◽  
Social Reinforcement ◽  
Self Administration ◽  
Contingent Access

Drug-using peers are recognized as a leading factor influencing drug use among adolescents and young adults. One mechanism by which peers influence drug use is by providing social reinforcement for using drugs. Social reinforcement may be provided in multiple ways, including by making social contact contingent on drug use (i.e., an individual must use drugs to gain/maintain access to a peer). The purpose of this study was to develop a preclinical model in which intravenous cocaine self-administration was positively reinforced by access to a social partner. Young adult male rats were trained to self-administer cocaine in operant conditioning chambers with a guillotine door that could be opened to an adjacent compartment housing either a social partner or a non-social stimulus. Once cocaine self-administration was established, the guillotine door was activated, and cocaine intake was reinforced by brief access to either a social (age- and sex-matched peer) or non-social (black-and-white athletic sock) stimulus. Contingent access to a social partner rapidly increased cocaine self-administration. Total cocaine intake was 2- to 3-fold greater in rats assigned to the social versus non-social condition across a 100-fold dose range. Cocaine intake rapidly increased when rats in the original non-social group were later provided with social partners, whereas cocaine intake resisted change and remained elevated when rats in the original social group had their partners removed. These data indicate that contingent access to a social partner increases drug intake and suggest that social reinforcement may represent a vulnerability factor that is particularly resistant to psychosocial interventions.

Meaning and significance of low density area (LDA) of renal cell carcinoma (RCC) on computed tomography (CT).

2018 ◽  
Vol 36 (6_suppl) ◽  
pp. 628-628
Author(s):  
Keita Shibayama ◽  
Go Kimura ◽  
Tatsuro Hayashi ◽  
Jun Akatsuka ◽  
Ryoji Kimata ◽  
...  
Keyword(s):  
Prognostic Significance ◽  
Nippon Medical School ◽  
Rank Test ◽  
Low Density ◽  
Pathological Features ◽  
Hydropic Degeneration ◽  
Central Necrosis ◽  
Density Area ◽  
Group A ◽  
Low Density Area

628 Background: LDA in solid RCC on CT is often interpreted as ‘central necrosis’ in routine clinical practice. However, the details of clinicopathological (CP) features of LDA of RCC on CT and their prognostic significance have not been shown. We retrospectively investigated LDA of RCC to clarify the CP features and prognostic significance. Methods: Of 428 surgically treated patients for RCC between January 2007 and March 2017 at Nippon Medical School hospital, we found 267 cases who had dynamic CT performed before operation. Among them, we selected and analyzed 199 consecutive cases whose tumor had low density area and whose cancer status resulted in no evidence of disease after surgery. We first examined pathological features of LDA. Then, we examined the correlation between pathological features of LDA and CP parameters and prognosis. The differences of values between the three groups were examined with the Kruskal-Wallis test. Recurrence free survival (RFS) was examined with the Kaplan-Meyer curves and the log-rank test. Results: The histology of LDA was divided into two groups: central necrosis (+) or (-: NN). Central necrosis (+) group was further divided into two subgroups: with neutrophilic infiltration (NI+) and without NI (NI-). This means that, in the end, there were three groups according to microscopic findings: group A (NI+, n = 20, 10%), B (NI-, n = 55, 28%), C (NN, n = 124, 62%). The pathological features of the NN group were composed of hyaline degeneration, hydropic degeneration, fibrosis, scars, and so on. The results of the comparison between CP parameters among the three groups were as follows: C-reactive protein, WBC, platelet, and alkaline phosphatase are statistically higher, and hemoglobin, triglyceride, and albumin were statistically lower in group A. CT value was statistically lower in group A and B. Median follow-up was 35months, and 3-year RFS (group A, B, C, p value) was (49.8%, 77.9%, 94.3%, p < 0.0001). Conclusions: In RCC patients only about one-third of LDA on CT was shown to be central necrosis. Necrosis with NI was clinically most closely associated with poor prognosis. Central necrosis may be predictive from lower CT values compared to non-necrotic tissues.

GROOMING AND COERCION IN ONE-MALE UNITS OF HAMADRYAS BABOONS: MARKET FORCES OR RELATIONSHIP CONSTRAINTS?

Behaviour ◽  
2002 ◽  
Vol 139 (11-12) ◽  
pp. 1525-1553 ◽  
Author(s):  
María Victoria Hernández-Lloreda ◽  
Félix Zaragoza ◽  
Fernando Colmenares
Keyword(s):  
Time Budget ◽  
Social Systems ◽  
Papio Hamadryas ◽  
Social Partner ◽  
Female Competition ◽  
Market Forces ◽  
Hamadryas Baboons ◽  
Social Time ◽  
Power Differentials ◽  
Constraint Model

AbstractIn the stable and cohesive social groups of primates (and other group-living mammals) individuals maintain long-lasting partnerships with a subset of their group companions. Such inter-individual relationships are based on the active exchange of a variety of affiliative, agonistic and cooperative behaviour patterns. Since these interactions influence the partners' biological fitness they are often regarded as 'services' or 'commodities' that are offered ('sold') and demanded ('bought') by individuals in order to cultivate those partnerships that best contribute to maximise their fitness. According to the biological markets theory, an individual's attractiveness as a social partner depends on the value of the services that it can provide and trade for, which depends on the levels of supply and demand, that is, a given service is more expensive to buy, the fewer are the individuals that offer it relative to the individuals that demand it. This paper uses data on grooming (i.e. investment and outbidding competition), female aggression (i.e. female contest competition), and male herding (i.e. male coercion) from a study of three differently-sized captive one-male, multi-female social systems of hamadryas baboons (Papio hamadryas) to test six biomarket-based predictions regarding the unit males' and females' allocation of grooming time and preferred grooming partnerships and the males' rate of coercion (Fig. 1). It was found that most core predictions were not borne out by the data. We propose an alternative model, namely, the 'constraint' model (Fig. 6), according to which the males' behaviour toward the females is expected to be constrained by the intensity of contest and outbidding competition with other males, by the number of relationships they have to service (i.e. their social time budget), and by how attractive (or valuable) they are to females. The latter should also influence the use of coercion by males. The females' behaviour toward the males is hypothesised to be constrained by the intensity of contest and outbidding competition with other females and by the extent of relationship conflict with males. Finally, female relationships are expected to be constrained by the males' behaviour, especially if they are prone to police female aggressive encounters, which contributes to reduce power differentials among them. Some of these predictions were supported by the data. Although both models share the view that an individual's availability, which is constrained by the social time budget already compromised, does influence his or her value as a social partner, the 'constraint' model does emphasise, in addition, that a male's accessibility, which is constrained by female competition, and quality (i.e. RHP), also contribute significantly to it and must be considered. Although market forces are likely to operate in the structuring of social relationships within primate groups, we suggest that their potential impact may be overriden in social systems in which contest and outbidding competition within trader classes, and conflict between trading partners, are strong. This effect should be even more exacerbated if power differentials among individuals are strong and if members of a trader class actively interfere the interactions of members of the other trader class, for example, by herding their affiliative interactions or by policing their agonistic encounters. In some kinds of animal social systems it appears that the main effect of demographic factors is to constrain the individuals' expression of their partner preferences and with it the possibility of detecting market forces.

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