Variation in Prey Capture Mechanics in the Swordtail,Xiphophorus helleriin Response to Food Type

2014 ◽  
Vol 45 (2) ◽  
pp. 59-63 ◽  
Author(s):  
Brandon Mackey ◽  
Keaton Vanderploeg ◽  
Lara A. Ferry
Keyword(s):  
2015 ◽  
Vol 46 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Geoffrey K. Lines ◽  
Anthony Blume ◽  
Lara A. Ferry

2020 ◽  
Vol 223 (21) ◽  
pp. jeb232868
Author(s):  
Daniel Schwarz ◽  
Stanislav N. Gorb ◽  
Alexander Kovalev ◽  
Nicolai Konow ◽  
Egon Heiss

ABSTRACTIntraoral food processing mechanisms are known for all major vertebrate groups, but the form and function of systems used to crush, grind or puncture food items can differ substantially between and within groups. Most vertebrates display flexible mechanisms of intraoral food processing with respect to different environmental conditions or food types. It has recently been shown that newts use cyclical loop-motions of the tongue to rasp prey against the palatal dentition. However, it remains unknown whether newts can adjust their food processing behavior in response to different food types or environmental conditions. Newts are interesting models for studying the functional adaptation to different conditions because of their unique and flexible lifestyle: they seasonally change between aquatic and terrestrial habitats, adapt their prey-capture mode to the respective environment, and consume diverse food types with different mechanical properties. Using X-ray high-speed recordings, anatomical investigations, behavioral analyses and mechanical property measurements, we tested the effects of the medium in which feeding occurs (water/air) and the food type (maggot, earthworm, cricket) on the processing behavior in Triturus carnifex. We discovered that food processing, by contrast to prey capture, differed only slightly between aquatic and terrestrial habitats. However, newts adjusted the number of processing cycles to different prey types: while maggots were processed extensively, earthworm pieces were barely processed at all. We conclude that, in addition to food mechanical properties, sensory feedback such as smell and taste appear to induce flexible processing responses, while the medium in which feeding occurs appears to have less of an effect.


2019 ◽  
Author(s):  
Aaron Matthius Eger ◽  
Rebecca J. Best ◽  
Julia Kathleen Baum

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.


2020 ◽  
Vol 16 (7) ◽  
pp. 1119-1129
Author(s):  
Nurul Hakimah ◽  
Nur Rahman ◽  
Sucipto Sucipto ◽  
Wignyanto Wignyanto ◽  
Aulanni'am Aulanni'am

Background: The purpose of this study was to analyze the menu engineering data: preferences, acceptances, and popularity indexes of local food package menus with low to moderate glycemic index and how these variables affect the glycemic response of subjects with type 2 diabetes mellitus (T2DM). Methods: This study was a one group pre and post-test experimental study with 21 T2DM participants. A total of 1,764 menu engineering data were obtained during the two-week study period. Fifteen food service survey questions were distributed and anthropometric and glycemic responses were measured. Results: The popularity indexes of the main and snack package menus were significantly different (p=0,000). There was a significant decrease (p<0.05) in Δ RBG levels by 59.6±115.8 mg/ dL (26.7%) and Δ % albumin glycated by 1.5±1.0 (6.1%) (p = 0.000) on 38% subjects with good glycemic control who consumed less food outside the study (12.5%). Price, type of food, type of foodstuff, nutrient content, portion size, food appearance, food texture, GI values, food menu name, and menu conformity to the environment were important considerations in the menu preference and popularity. Conclusion: This study showed that the local food package menu can control the glycemic response of T2DM participants while having a high popularity index. This finding provides an opportunity for the foodservice industry to operate sustainably by considering the factors desired by consumers with T2DM in controlling their long-term glycemic response.


Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2710 ◽  
Author(s):  
April Callister ◽  
Joanna Gautney ◽  
Christina Aguilar ◽  
Julian Chan ◽  
David Aguilar

Multiple studies have demonstrated strong links between diet and anemia, but few have explored the impact of food groups on hemoglobin (Hb). We analyzed the correlation between Ghanaian diet and Hb levels to explore reduction of anemia prevalence through dietary interventions. Demographics, food frequency questionnaires (FFQ), and blood samples were obtained from 140 volunteers (ages 18–65) in five locations across Ghana. Hb was measured; estimated iron consumption was calculated. FFQ items were grouped by food type, and a regression analysis was performed to determine the most important dietary predictors of Hb. Moreover, 47% of total participants were anemic; 64% of females and 28% of males. Hb levels were highest in Mole (13.9 g/dL, SD = ±1.9), independent of sex distribution. The regression model revealed a 62.7% adjusted correlation between food groups and Hb levels. Animal foods (β = 0.016, t = 5.08, p < 0.01) and plant protein (β = 0.013, t = 2.86, p < 0.01) were the most influential groups to Hb levels. It is of vital importance to emphasize the benefits of consuming animal foods and plant proteins within the Ghanaian population. The ease of access to plant proteins makes it likely that this food group will be most influential and have the greatest impact in reduction of anemia in the Ghanaian population.


Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 112
Author(s):  
Bianca op den Brouw ◽  
Francisco C. P. Coimbra ◽  
Lachlan A. Bourke ◽  
Tam Minh Huynh ◽  
Danielle H. W. Vlecken ◽  
...  

Snakes of the genera Pseudocerastes and Eristicophis (Viperidae: Viperinae) are known as the desert vipers due to their association with the arid environments of the Middle East. These species have received limited research attention and little is known about their venom or ecology. In this study, a comprehensive analysis of desert viper venoms was conducted by visualising the venom proteomes via gel electrophoresis and assessing the crude venoms for their cytotoxic, haemotoxic, and neurotoxic properties. Plasmas sourced from human, toad, and chicken were used as models to assess possible prey-linked venom activity. The venoms demonstrated substantial divergence in composition and bioactivity across all experiments. Pseudocerastes urarachnoides venom activated human coagulation factors X and prothrombin and demonstrated potent procoagulant activity in human, toad, and chicken plasmas, in stark contrast to the potent neurotoxic venom of P. fieldi. The venom of E. macmahonii also induced coagulation, though this did not appear to be via the activation of factor X or prothrombin. The coagulant properties of P. fieldi and P. persicus venoms varied among plasmas, demonstrating strong anticoagulant activity in the amphibian and human plasmas but no significant effect in that of bird. This is conjectured to reflect prey-specific toxin activity, though further ecological studies are required to confirm any dietary associations. This study reinforces the notion that phylogenetic relatedness of snakes cannot readily predict venom protein composition or function. The significant venom variation between these species raises serious concerns regarding antivenom paraspecificity. Future assessment of antivenom is crucial.


Author(s):  
Alejandro G. Farji-Brener ◽  
Agostina S. Juncosa-Polzella ◽  
Daniela Madrigal-Tejada ◽  
Diego Centeno-Alvarado ◽  
Mariana Hernández-Soto ◽  
...  
Keyword(s):  

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 559
Author(s):  
Lakshminath Kundanati ◽  
Prashant Das ◽  
Nicola M. Pugno

Aquatic predatory insects, like the nymphs of a dragonfly, use rapid movements to catch their prey and it presents challenges in terms of movements due to drag forces. Dragonfly nymphs are known to be voracious predators with structures and movements that are yet to be fully understood. Thus, we examine two main mouthparts of the dragonfly nymph (Libellulidae: Insecta: Odonata) that are used in prey capturing and cutting the prey. To observe and analyze the preying mechanism under water, we used high-speed photography and, electron microscopy. The morphological details suggest that the prey-capturing labium is a complex grasping mechanism with additional sensory organs that serve some functionality. The time taken for the protraction and retraction of labium during prey capture was estimated to be 187 ± 54 ms, suggesting that these nymphs have a rapid prey mechanism. The Young’s modulus and hardness of the mandibles were estimated to be 9.1 ± 1.9 GPa and 0.85 ± 0.13 GPa, respectively. Such mechanical properties of the mandibles make them hard tools that can cut into the exoskeleton of the prey and also resistant to wear. Thus, studying such mechanisms with their sensory capabilities provides a unique opportunity to design and develop bioinspired underwater deployable mechanisms.


Sign in / Sign up

Export Citation Format

Share Document