scholarly journals Testing Darwin’s hypothesis about the most wonderful plant in the world: The Venus flytrap’s marginal spikes are a ‘horrid prison’ for moderate-sized insect prey

2018 ◽  
Author(s):  
Alexander L. Davis ◽  
Matthew H. Babb ◽  
Brandon T. Lee ◽  
Christopher H. Martin
Keyword(s):  
Prey Capture ◽  
Feeding Strategy ◽  
Adaptive Landscape ◽  
Large Prey ◽  
Capture Success ◽  
Dionaea Muscipula ◽  
Lab Experiments ◽  
Morphological Adaptations ◽  
The World ◽  
Laboratory Results

AbstractBotanical carnivory is a novel feeding strategy associated with numerous physiological and morphological adaptations. However, the benefits of these novel carnivorous traits are rarely tested. Here, we used field observations and lab experiments to test the prey capture function of the marginal spikes on snap traps of the Venus flytrap (Dionaea muscipula). Our field and laboratory results suggested surprisingly inefficient capture success: fewer than 1 in 4 prey encounters led to prey capture. Removing the marginal spikes decreased the rate of prey capture success for moderate-sized cricket prey by 90%, but this effect disappeared for larger prey. The nonlinear benefit of spikes suggests that they provide a better cage for capturing more abundant insects of moderate and small sizes, but may also provide a foothold for rare large prey to escape. Our observations support Darwin’s hypothesis that the marginal spikes form a ‘horrid prison’ that increases prey capture success for moderate-sized prey, but the decreasing benefit for larger prey is unexpected and previously undocumented. Thus, we find surprising complexity in the adaptive landscape for one of the most wonderful evolutionary innovations among all plants. These findings further enrich our understanding of the evolution and diversification of novel trap morphology in carnivorous plants.

scholarly journals How within-group behavioural variation and task efficiency enhance fitness in a social group

2010 ◽  
Vol 278 (1709) ◽  
pp. 1209-1215 ◽  
Author(s):  
Jonathan N. Pruitt ◽  
Susan E. Riechert
Keyword(s):  
Prey Capture ◽  
Common Garden ◽  
Division Of Labour ◽  
Large Prey ◽  
Task Specialization ◽  
Capture Success ◽  
Social Phenotype ◽  
Individual Task ◽  
Task Efficiency

How task specialization, individual task performance and within-group behavioural variation affects fitness is a longstanding and unresolved problem in our understanding of animal societies. In the temperate social spider, Anelosimus studiosus , colony members exhibit a behavioural polymorphism; females either exhibit an aggressive ‘asocial’ or docile ‘social’ phenotype. We assessed individual prey-capture success for both phenotypes, and the role of phenotypic composition on group-level prey-capture success for three prey size classes. We then estimated the effect of group phenotypic composition on fitness in a common garden, as inferred from individual egg-case masses. On average, asocial females were more successful than social females at capturing large prey, and colony-level prey-capture success was positively associated with the frequency of the asocial phenotype. Asocial colony members were also more likely to engage in prey-capture behaviour in group-foraging situations. Interestingly, our fitness estimates indicate females of both phenotypes experience increased fitness when occupying colonies containing unlike individuals. These results imply a reciprocal fitness benefit of within-colony behavioural variation, and perhaps division of labour in a spider society.

scholarly journals Flexibility in feeding behaviour may compensate for morphological constraints of fossoriality in the amphisbaenian Blanus cinereus

2013 ◽  
Vol 34 (2) ◽  
pp. 241-247 ◽  
Author(s):  
Pilar López ◽  
Pilar López ◽  
José Martín ◽  
Pilar López ◽  
José Martín ◽  
...  
Keyword(s):  
Feeding Behaviour ◽  
Prey Capture ◽  
Prey Type ◽  
Large Prey ◽  
Morphological Adaptation ◽  
Trophic Resources ◽  
Morphological Adaptations ◽  
Small Head ◽  
Gape Size

Morphological adaptations for burrowing, such as an elongated body, and a small head may constrain feeding behaviour in fossorial reptiles. We experimentally examined the effect of prey type on prey capture and handling behaviour of the amphisbaenian Blanus cinereus. This amphisbaenian showed four different handling modes according to the characteristics of each prey type. When prey diameter was narrower than gape-size, prey were consumed without prey processing; when prey diameter was wider than gape-size, B. cinereus shifted handling mode to prey processing. Amphisbaenians scraped or tore off bite-sized pieces of large prey and showed longer handling times for some prey types than most epigean saurians. Flexibility in feeding behaviour may allow amphisbaenians to exploit variable underground trophic resources, overcoming constraints of morphological adaptation to fossoriality.

Prey capture in the Venus flytrap: collection or selection?

Botany ◽  
2009 ◽  
Vol 87 (10) ◽  
pp. 1007-1010 ◽  
Author(s):  
John J. Hutchens, ◽  
James O. Luken
Keyword(s):  
Resource Availability ◽  
Charles Darwin ◽  
Prey Capture ◽  
Large Prey ◽  
Venus Flytrap ◽  
Dionaea Muscipula ◽  
Plant Allocation ◽  
Trap Size ◽  
Prey Length ◽  
Best Fit

Charles Darwin first proposed that the Venus flytrap ( Dionaea muscipula Ellis) functions optimally by capturing and digesting large prey, the small prey escaping through openings at the trap margins. This hypothesis, although intuitively sound in the context of trap mechanics or plant allocation theory, has not been tested adequately with populations of plants growing in the field. Here, with traps collected in the endemic habitat over 9 months, we show that prey capture in the Venus flytrap is opportunistic rather than selective. While there was no effect of trap size on prey capture success, there was a significant but weak positive relationship between trap length and prey length. Prey sizes were well below the theoretical maximum holding capacities of traps and relatively small insects were represented across the range of trap sizes. Our results show that prey capture was not biased toward large invertebrates. Instead, we suggest that nonselective prey capture across the observed range of trap sizes is the best-fit explanation of trap function in the context of relatively limited ability to change allocation in response to sudden increases in resource availability.

scholarly journals Marine Protection Induces Morphological Variation in the California Moray, Gymnothorax mordax

2020 ◽  
Vol 60 (2) ◽  
pp. 522-534
Author(s):  
Rita S Mehta ◽  
Katherine E Dale ◽  
Benjamin A Higgins
Keyword(s):  
Local Community ◽  
Prey Capture ◽  
Feeding Habits ◽  
Feeding Strategy ◽  
Marine Conservation ◽  
Large Prey ◽  
Community Interactions ◽  
Conservation Area ◽  
Adductor Muscles ◽  
Insight Into

Synopsis The effectiveness of marine protected areas (MPAs) on the general health and conservation of species, habitats, and community interactions is of great interest to researchers, managers, and recreationalists. However, the ecological and behavioral diversity of vertebrate predators of southern California kelp forests limits our ability to make general conclusions about MPA effectiveness across a variety of species. Identifying and studying species with extreme feeding habits or prey-capture strategies may offer greater insight into predator–prey relationships and reveal the trophic importance of an animal in the larger community. Moray eels (family Muraenidae) have been shown to have morphological and behavioral adaptations that allow them to consume large prey whole, identifying them as important predators. From 2015 to 2018, we studied the health and feeding behavior of a long-lived, elusive, and benthic kelp forest predator, the California moray eel (Gymnothorax mordax). We trapped eels inside and outside of Blue Cavern Onshore State Marine Conservation Area, an MPA on the northwest side of Santa Catalina Island, CA which prohibits the take of any species. Over 4 years, we captured 1736 eels. Overall, we found that morays were longer, older, heavier, had higher body condition, and were found in greater abundance within the MPA. Although fish comprised the majority of their summer diet, morays outside of the MPA were consuming a more diverse set of fish, while kelp bass comprised more than half of the diet for morays inhabiting the MPA. Additionally, we found that morays within the MPA had larger relative vertical gape distances (VGDs) and narrower heads. Our recapture data support the high site fidelity of morays, indicating that their diet and morphology are influenced by their local community. While the majority of morays are thriving in the MPA, as suggested by their robust sizes and longevity, high abundance appears to result in higher frequencies of cannibalism, the presence of an undescribed disease, and lower growth rates. Our results suggest that the MPA affects the life history of morays and may select for an alternative feeding strategy in which eels develop larger VGDs, smaller adductor muscles, and a specialized diet which is presumably influenced by the local environment. In addition, observations of cannibalistic behavior and species-specific disease provide us with important insight into natural factors that may still regulate populations removed from anthropogenic disturbances such as fishing.

Functional implications of supercontracting muscle in the chameleon tongue retractors

2001 ◽  
Vol 204 (21) ◽  
pp. 3621-3627 ◽  
Author(s):  
Anthony Herrel ◽  
Jay J. Meyers ◽  
Peter Aerts ◽  
Kiisa C. Nishikawa
Keyword(s):  
Prey Capture ◽  
Three Dimensional ◽  
Force Production ◽  
Retractor Muscle ◽  
Muscle Physiology ◽  
Large Prey ◽  
Wide Range ◽  
Ambush Predators ◽  
Full Body

SUMMARYChameleons capture prey items using a ballistic tongue projection mechanism that is unique among lizards. During prey capture, the tongue can be projected up to two full body lengths and may extend up to 600 % of its resting length. Being ambush predators, chameleons eat infrequently and take relatively large prey. The extreme tongue elongation (sixfold) and the need to be able to retract fairly heavy prey at any given distance from the mouth are likely to place constraints on the tongue retractor muscles. The data examined here show that in vivo retractor force production is almost constant for a wide range of projection distances. An examination of muscle physiology and of the ultrastructure of the tongue retractor muscle shows that this is the result (i) of active hyoid retraction, (ii) of large muscle filament overlap at maximal tongue extension and (iii) of the supercontractile properties of the tongue retractor muscles. We suggest that the chameleon tongue retractor muscles may have evolved supercontractile properties to enable a substantial force to be produced over a wide range of tongue projection distances. This enables chameleons successfully to retract even large prey from a variety of distances in their complex three-dimensional habitat.

scholarly journals How to Avoid Black Markets for Appointments with Online Booking Systems

2021 ◽  
Vol 111 (7) ◽  
pp. 2127-2151
Author(s):  
Rustamdjan Hakimov ◽  
C.-Philipp Heller ◽  
Dorothea Kübler ◽  
Morimitsu Kurino
Keyword(s):  
Market Design ◽  
Current System ◽  
Black Markets ◽  
High Demand ◽  
Public Authorities ◽  
Batch System ◽  
Lab Experiments ◽  
Time Period ◽  
The World

Allocating appointment slots is presented as a new application for market design. Online booking systems are commonly used by public authorities to allocate appointments for visa interviews, driver’s licenses, passport renewals, etc. We document that black markets for appointments have developed in many parts of the world. Scalpers book the appointments that are offered for free and sell the slots to appointment seekers. We model the existing first-come-first-served booking system and propose an alternative batch system. The batch system collects applications for slots over a certain time period and then randomly allocates slots to applicants. The theory predicts and lab experiments confirm that scalpers profitably book and sell slots under the current system with sufficiently high demand, but that they are not active in the proposed batch system. We discuss practical issues for the implementation of the batch system and its applicability to other markets with scalping. (JEL C92, D47)

scholarly journals First evidence of prey capture and meat eating by wild Yunnan snub-nosed monkeys Rhinopithecus bieti in Yunnan, China

2010 ◽  
Vol 56 (2) ◽  
pp. 227-231 ◽  
Author(s):  
Baoping Ren ◽  
Dayong Li ◽  
Zhijin Liu ◽  
Baoguo Li ◽  
Fuwen Wei ◽  
...  
Keyword(s):  
Nonhuman Primates ◽  
Prey Capture ◽  
Dietary Diversity ◽  
Group Structure ◽  
Feeding Strategy ◽  
Rhinopithecus Bieti ◽  
Spatial Spread ◽  
Meat Eating ◽  
Begging Behavior ◽  
Animal Consumption

Abstract Most extant nonhuman primates occasionally prey on fast-moving, warm-blooded animals; however, Indriidae, Lepilemuridae, and Colobinae either scavenged for meat or did not eat meat at all. Here we report six cases of animal consumption by the snub-nosed monkey Rhinopithecus bieti in a wild, habituated group between 2004 and 2009 in Yunnan, China. At present, only males in an all-male unit within the study group were involved in active hunting. Such a male-biased activity may be related to the group structure and spatial spread of R. bieti. Two females were observed eating freshly killed birds. The findings confirmed that R. bieti engaged in scavenging and, when hunting, employed a cranio-cervical bite to kill their prey. Meat eating is likely a nutrient maximization feeding strategy in R. bieti, especially in males. A begging behavior occurred after successful prey capture. Although begging was observed, no sharing of the meat was seen. The present findings illuminate the dietary diversity of R. bieti and their ability to expand their dietary spectrum.

scholarly journals Temperature and Estrogen Alter Predator–Prey Interactions between Fish Species

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
J L Ward ◽  
V Korn ◽  
A N Auxier ◽  
H L Schoenfuss
Keyword(s):  
Prey Capture ◽  
Abiotic Factors ◽  
Pimephales Promelas ◽  
Lepomis Macrochirus ◽  
Environmental Estrogens ◽  
Fathead Minnows ◽  
Predator Prey ◽  
Food Web Interactions ◽  
Capture Success ◽  
High Concentrations

Synopsis A variety of environmental estrogens are commonly detected in human-impacted waterways. Although much is known about the effects of these environmental estrogens on the reproductive physiology and behavior of individuals within species, comparatively less is known about how these compounds alter the outcomes of interactions between species. Furthermore, few studies have considered how the effects of contaminants are modulated by natural variation in abiotic factors, such as temperature. To help fill this knowledge gap, we conducted a factorial experiment to examine the independent and combined effects of estrone (E1) and temperature on the outcome of predator–prey interactions between two common North American freshwater fishes, fathead minnows (Pimephales promelas) and bluegill sunfish (Lepomis macrochirus). Larval fathead minnows and adult sunfish were exposed to either a low (mean±standard deviation, 90.1 ± 18 ng/L; n = 16) or high (414 ± 147 ng/L; n = 15) concentration of E1 or to a solvent control for 30 days at one of four natural seasonal temperatures (15°C, 18°C, 21°C, and 24°C) before predation trials were performed. Exposure to E1 was associated with a significant increase in larval predation mortality that was independent of temperature. Across all temperature treatments, approximately 74% of control minnows survived; this survivorship significantly exceeded that of minnows exposed to either concentration of E1 (49% and 53% for minnows exposed to the low and high concentrations, respectively). However, exposure to E1 also impaired the prey-capture success of sunfish, partially mitigating predation pressure on exposed minnows. Overall prey-capture success by sunfish showed an inverted U-shaped distribution with temperature, with maximal prey consumption occurring at 21°C. This study illustrates the vulnerability of organismal interactions to estrogenic pollutants and highlights the need to include food web interactions in assessments of risk.

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