scholarly journals A matter of time and proportion: the availability of phosphorus-rich phytoplankton influences growth and behavior of copepod nauplii

2020 ◽  
Vol 42 (5) ◽  
pp. 530-538
Author(s):  
Cédric L Meunier ◽  
Emily M Herstoff ◽  
Carla Geisen ◽  
Maarten Boersma
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Behavioral Adjustment ◽  
Short Exposure ◽  
Negative Consequences ◽  
Selective Feeding ◽  
Resource Quality ◽  
High Quality ◽  
P Content ◽  
And Behavior

Abstract Although consumers may use selective feeding to cope with suboptimal resource quality, little work has examined the mechanisms that underlie selective feeding, the efficiency of this behavior or its influence on consumer growth rate. Furthermore, a consumer’s exposure to suboptimal resources may also influence the consumer’s behavior and life history, including growth rate. Here, we studied how the availability of P-rich and P-poor phytoplankton influences the growth and behavior of copepod nauplii. We observed that copepod nauplii preferentially feed on P-rich prey. We also found that even relatively short exposure to P-rich phytoplankton yielded higher nauplii growth rates, whereas the presence of P-poor phytoplankton in a mixture impaired growth. Overall, we observed that swimming speed decreased with increasing phytoplankton P-content, which is a behavioral adjustment that may improve utilization of heterogeneously distributed high-quality food in the field. Based on our results, we propose that the optimal prey C: P ratio for copepod nauplii is very narrow, and that deviations from this optimum have severe negative consequences for growth.

scholarly journals Ontogenetic changes in the elemental composition and stoichiometry of marine copepods with different life history strategies

2020 ◽  
Vol 42 (3) ◽  
pp. 320-333 ◽  
Author(s):  
Enric Saiz ◽  
Kaiene Griffell ◽  
Albert Calbet
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Elemental Composition ◽  
Growth Rates ◽  
Stoichiometric Composition ◽  
Maximum Growth ◽  
Life History Strategies ◽  
Ontogenetic Variation ◽  
Ontogenetic Changes ◽  
P Content

Abstract We describe the ontogenetic variation in elemental and stoichiometric composition of two copepod species with very contrasted life history patterns, the calanoid Paracartia grani and the cyclopoid Oithona davisae. The first species is a broadcasting, highly productive copepod, whereas the latter is an egg-carrying copepod, much less productive. We reared cultures of both species under conditions of excess food and analyzed their C, N and P composition, and their molar ratios, along development. Both species differed on their specific P content, whereas the specific C and N content were similar. As expected, the specific P content of P. grani was higher, resulting in lower C:P and N:P ratios. Furthermore, we compared our elemental composition data with previously reported stage-specific (nauplii and adult female) maximum growth rates of these two species. We found that for O. davisae, the ontogenetic variation in specific P content agreed with the reported differences in growth rate along development; however, in the case of P. grani, in which juvenile and adult maximum growth rates are similar, the variations in specific P content along development did not reflect the growth rate pattern.

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

scholarly journals Biological Impact of Photoperiod on Fairy Shrimp (Branchinecta orientalis): Life History and Biochemical Composition

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 695
Author(s):  
Sara Farhadi ◽  
Behrooz Atashbar Kangarloei ◽  
Ahmad Imani ◽  
Kourosh Sarvi Moghanlou
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Protein Content ◽  
Biochemical Composition ◽  
Digestive Enzyme ◽  
Total Body Length ◽  
Constant Darkness ◽  
Fairy Shrimp ◽  
Daily Growth ◽  
Isoleucine Leucine

B. orientalis, fairy shrimp, is often among the most conspicuous invertebrates inhabiting temporary aquatic habitats with a typical variation in environmental conditions. Its life history characteristics and biochemical composition were studied under four different photoperiodic regimes (24L:0D, 0L:24D, 16L:8D, and 12L:12D). The significantly highest cumulative and initial hatching rates (48 h) were obtained at 24L:0D (p < 0.05). Cultivating the larvae under different photoperiods did not significantly affect specific growth rate (SGR) (p > 0.05). However, higher final total body length and daily growth rate were recorded under constant darkness. Higher lipid content was found at 24L:0D to the extent that it was more than two times higher than that at 16L:8D and 12L:12D (p < 0.05). There was also a remarkable increase in body crude protein content at 24L:0D (p < 0.05). Body fatty-acid profiles of the fairy shrimps were also affected by culture condition (p < 0.05). Extension of lighting period resulted in a subtle increase in body contents of arginine, lysine, histidine, isoleucine, leucine, valine, methionine, and phenylalanine, especially in the group kept under a 16L:8D regime. The highest and lowest digestive enzyme activity was observed at 0L:24D and 24L:0D, respectively (p < 0.05). In contrast, the highest and lowest soluble protein content was recorded at 24L:0D and 0L:24D, respectively (p < 0.05). Similarly, antioxidant status was significantly higher at 0L:24D (p < 0.05). In conclusion, a 16L:8D light–dark cycle might be an optimal condition in terms of growth performance and physio-biochemical characteristics. These findings could be helpful in optimizing the rearing conditions for upscaling B. orientalis production.

scholarly journals Positive Emotions Boost Enthusiastic Responsiveness to Capitalization Attempts. Dissecting Self-Report, Physiology, and Behavior

2021 ◽  
Author(s):  
Lukasz D. Kaczmarek ◽  
Todd B. Kashdan ◽  
Maciej Behnke ◽  
Martyna Dziekan ◽  
Ewelina Matuła ◽  
...  
Keyword(s):  
Positive Emotions ◽  
Negative Emotions ◽  
Emotional Valence ◽  
Self Report ◽  
Physiological Reactivity ◽  
Direct Effects ◽  
High Quality ◽  
Video Clips ◽  
And Behavior ◽  
Positive And Negative Emotions

AbstractWhen individuals communicate enthusiasm for good events in their partners' lives, they contribute to a high-quality relationship; a phenomenon termed interpersonal capitalization. However, little is known when individuals are more ready to react enthusiastically to the partner's success. To address this gap, we examined whether positive and negative emotions boost or inhibit enthusiastic responses to partner's capitalization attempts (RCA). Participants (N = 224 individuals) responded to their partner's success. Before each capitalization attempt (operationalized as responses following the news that their partner won money in a game), we used video clips to elicit positive (primarily amusement) or negative (primarily anger) or neutral emotions in the responder. We recorded emotional valence, smiling intensity, verbal RCA, and physiological reactivity. We found indirect (but not direct) effects such that eliciting positive emotions boosted and negative emotions inhibited enthusiastic RCA (smiling intensity and enthusiastic verbal RCA). These effects were relatively small and mediated by emotional valence and smiling intensity but not physiological reactivity. The results offer novel evidence that positive emotions fuel the capitalization process.

Life History and Behavior of the Bramble Leafhopper, Ribautiana tenerrima (H.-S.) (Homoptera: Cicadellidae)

1960 ◽  
Vol 92 (1) ◽  
pp. 10-20 ◽  
Author(s):  
J. Raine
Keyword(s):  
Life History ◽  
North America ◽  
Vancouver Island ◽  
Dry Season ◽  
Lower Fraser Valley ◽  
And Behavior ◽  
Fraser Valley

Since 1947, when the bramble leafhopper, Ribautiana tenerrima (H.-S.) (rubi Hardy, misella 13011.), was first reported in North America near Victoria, B.C., it has become a serious pest in cane fruit plantings on southern Vancouver Island and the lower Fraser Valley. Hoth nymphs and adults suck the sap from the leaves, producing a white stippling on the upper surfaces (Fig. 1). In a dry season a severe infestation causes many leaves to become curled and appear burned. The canes lack vigor and the size of the fruit is reduced. This is a report on a study of the life history and behavior of the species conducted at Victoria from 1953 to 1957.

Supporting Young Children’s Development of Executive Function Through Early Mathematics

2021 ◽  
Vol 8 (2) ◽  
pp. 192-199
Author(s):  
Christina Mulcahy ◽  
Crystal A. Day Hess ◽  
Douglas H. Clements ◽  
Jasmine R. Ernst ◽  
Sarah E. Pan ◽  
...  
Keyword(s):  
Executive Function ◽  
Mathematics Achievement ◽  
Mathematics Teaching ◽  
Early Childhood Teachers ◽  
Academic Skills ◽  
High Quality ◽  
Alternative Strategies ◽  
Early Mathematics ◽  
General Skills ◽  
And Behavior

Early childhood teachers face competing instructional priorities to support specific academic skills and general skills that underlie learning, such as executive function (EF) skills that allow children to control their own thinking and behavior. As the evidence shows, EF skills predict later mathematics achievement, and early mathematics predicts later EF. These relations between mathematics and EF suggest high-quality mathematics teaching has a dual benefit: Teachers can promote children’s math and EF competencies by embedding support for EF in high-quality mathematics activities. Children benefit when guided to reflect on solutions and alternative strategies, and teachers benefit from guidance on how to support both math and EF. Finally, research on teachers developing both domains can inform educational policy.

scholarly journals A view into clinical practice guidelines: who uses them, who doesn’t and possibly, why

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Mihaela C. Munteanu ◽  
Julie Choi Jordan
Keyword(s):  
Clinical Practice ◽  
Clinical Practice Guidelines ◽  
Practice Guidelines ◽  
Healthcare Providers ◽  
Medical Professional ◽  
Physician Attitudes ◽  
Negative Consequences ◽  
Access To Treatment ◽  
Medical Specialties ◽  
And Behavior

Medical professional societies each develop specific clinical practice guidelines (CPGs). Based on the best available evidence, CPGs are intended to control variability and optimize quality of care in clinical practice. Yet, healthcare providers often do not accept or adhere to guidelines, but their reasons are not fully understood. When providers opt to choose not to follow CPGs, unfavorable patient outcomes including unequal access to treatment become negative consequences. In this small qualitative study, we will explore what causes non-adherence to CPGs and what changes have been made to CPGs from when physicians completed their medical residencies to the present. We interviewed physicians from a variety of medical specialties to assess how these changes may influence guideline adherence as well as the consequences of not following them. We found that guidelines may not be followed in cases where patients have comorbidities that are not described in the guidelines or when physicians do not incorporate new evidence and technology advances into their practice. In some specialties, physicians can develop a poor reputation if they do not adhere to the CPGs, and managed care agencies may deny reimbursement for care they provided. To best serve the physician and the patient, we need to find ways to improve CPG adherence. Tactics such as improving the methodology of CPG formation, using information technology, and creating ways to change physician attitudes and behavior are all viable options.

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