Accessing foods can exert multiple distinct, and potentially competing, selective pressures on feeding in common marmoset monkeys
apparatus; behavior; Callithrix; callithrix-jacchus-jacchus; enamel thickness; evolution; feeding adaptations; food; food choice; Food mechanical properties; food selection; hardness; masticatory; mechanical defenses; morphology; prey size; processing; red deer; resource acquisition; tree gouging; Zoology
Animals must overcome the physical properties protecting foods to obtain nutrition. While animals can experience selection for traits that facilitate resource exploitation, specific feeding behaviors may entail multiple, different mechanical challenges with each potentially eliciting distinct selection pressures. Tree gouging by common marmosets (Primates: Callithrix jacchus) provides an illustrative case for studying these distinct mechanical challenges and their correlated behaviors and morphologies. We test the hypothesis that marmosets respond differently to three sequential mechanical stages of bark removal: (1) indentation; (2) crack initiation; (3) crack propagation. By surveying trees gouged by free-ranging marmosets in Pernambuco, Brazil, we found that mechanical variables related to crack initiation (fracture toughness, critical strain energy release rate and elastic modulus) were inversely correlated with measures of gouging intensity, with less mechanically challenging trees being gouged more intensely. Because crack initiation is likely the most mechanically challenging aspect of tree gouging, behavioral preference for less challenging resources likely allows marmosets to reduce costs and potential risks associated with accessing exudates. Variables related to bark indentation (hardness and friction) showed no relationship to the intensity of gouging behavior. Contrary to our prediction, trees with greater mechanical challenges for crack propagation (work to peel) were gouged more intensely. We attribute this pattern of gouging trees requiring greater effort in crack propagation to an inverse correlation between work to peel and fracture toughness in our tree sample. Importantly, marmosets exhibit morphological specializations of the feeding apparatus that facilitate indentation and crack propagation, potentially mitigating the need for behavioral choice. Here we show that extracting a single food resource can exert a series of distinct, potentially competing, selective forces during resource acquisition. This study illustrates how animals combine behaviors and morphological specializations to competently overcome distinct mechanical challenges, emphasizing the need for holistic approaches in understanding feeding adaptations.
Thompson C L; Valenca-Montenegro M M; Melo Lcdo; Valle Y B M; Oliveira Mabd; Lucas P W; Vinyard C J
Journal of Zoology
2014
2014-11
Journal Article
<a href="http://doi.org/10.1111/jzo.12164" target="_blank" rel="noreferrer noopener">10.1111/jzo.12164</a>
Differential training sequence effect upon psychostimulant discrimination.
Alkaloids/pharmacology; Animals; Appetite Depressants/pharmacology; Central Nervous System Stimulants/*pharmacology; Discrimination Learning/*drug effects; Dose-Response Relationship; Drug; Food; Male; Phenylpropanolamine/pharmacology; Psychotropic Drugs/pharmacology; Rats; Reinforcement Schedule; Sprague-Dawley
1. Previous studies indicate that rats trained to discriminate either cathinone or cathine from its vehicle have a diminished discriminative performance when tested 24 hours after a drug administration when compared to tests conducted after a vehicle administration. The phenomenon of rapid tolerance may occur to produce a lessened interceptive cue on the test day following administration of the drug. It would, therefore, be probable that when rats are trained with consecutive cathinone or cathine administrations they would perform less well than if they were trained with these drugs never given in consecutive training sessions. 2. To test this hypothesis, rats were trained with 0.8 mg/kg
Schechter M D
Progress in neuro-psychopharmacology & biological psychiatry
1993
1993-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0278-5846(93)90051-s" target="_blank" rel="noreferrer noopener">10.1016/0278-5846(93)90051-s</a>
Global and Historical Distribution of Clostridioides difficile in the Human Diet (1981-2019): Systematic Review and Meta-Analysis of 21886 Samples Reveal Sources of Heterogeneity, High-Risk Foods, and Unexpected Higher Prevalence Toward the Tropic.
antibiotic-resistance; beef; c; C. difficile; chicken meat; contamination; difficile; epidemiology; fecal samples; food; global; ground meat-products; one health; resistant staphylococcus-aureus; retail meat; toxin genes; vegetables
Clostridioides difficile (CD) is a spore-forming bacterium that causes life-threatening intestinal infections in humans. Although formerly regarded as exclusively nosocomial, there is increasing genomic evidence that person-to-person transmission accounts for only <25% of cases, supporting the culture-based hypothesis that foods may be routine sources of CD-spore ingestion in humans. To synthesize the evidence on the risk of CD exposure via foods, we conducted a systematic review and meta-analysis of studies reporting the culture prevalence of CD in foods between January 1981 and November 2019. Meta-analyses, risk-ratio estimates, and meta-regression were used to estimate weighed-prevalence across studies and food types to identify laboratory and geographical sources of heterogeneity. In total, 21886 food samples were tested for CD between 1981 and 2019 (96.4%, n = 21084, 2007-2019; 232 food-sample-sets; 79 studies; 25 countries). Culture methodology, sample size and type, region, and latitude were sources of heterogeneity (p < 0.05). Although non-strictly-anaerobic methods were reported in some studies, and we confirmed experimentally that improper anaerobiosis of media/sample-handling affects CD recovery in agar (Fisher, p < 0.01), most studies (>72%) employed the same (one-of-six) culture strategy. Because the prevalence was also meta-analytically similar across six culture strategies reported, all studies were integrated using three meta-analytical methods. At the study level (n = 79), the four-decade global cumulative-prevalence of CD in the human diet was 4.1% (95%CI = -3.71, 11.91). At the food-set level (n = 232, mean 12.9 g/sample, similar across regions p > 0.2; 95%CI = 9.7-16.2), the weighted prevalence ranged between 4.5% (95%CI = 3-6%; all studies) and 8% (95%CI = 7-8%; only CD-positive-studies). Risk-ratio ranking and meta-regression showed that milk was the least likely source of CD, while seafood, leafy green vegetables, pork, and poultry carried higher risks (p < 0.05). Across regions, the risk of CD in foods for foodborne exposure reproducibly decreased with Earth latitude (p < 0.001). In conclusion, CD in the human diet is a global non-random-source of foodborne exposure that occurs independently of laboratory culture methods, across regions, and at a variable level depending on food type and latitude. The latitudinal trend (high
Rodriguez-Palacios Alexander; Mo Kevin Q; Shah Bhavan U; Msuya Joan; Bijedic Nina; Deshpande Abhishek; Ilic Sanja
Frontiers in medicine
2020
1905-07
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
journalArticle
<a href="http://doi.org/10.3389/fmed.2020.00009" target="_blank" rel="noreferrer noopener">10.3389/fmed.2020.00009</a>