scholarly journals Large-scale ciliary reversal mediates capture of individual algal prey by Müller’s larva

2019 ◽  
Author(s):  
George von Dassow ◽  
Christina I. Ellison

AbstractWe documented capture of microalgal prey by several species of wild-caught Müller’s larvae of polyclad flatworm. To our knowledge, this is the first direct observation of feeding mechanism in this classical larval type. High-speed video recordings show that virtually all captures are mediated by large-scale transient ciliary reversal over one or more portions of the main ciliary band corresponding to individual lobes or tentacles. Local ciliary beat reversals alter near-field flow to suck parcels of food-containing water mouthward. Many capture episodes entail sufficient coordinated flow disruption that these compact-bodied larvae tumble dramatically. Similar behaviors were recorded in at least four distinct species, one of which corresponds to the ascidian-eating polyclad Pseudoceros.

1999 ◽  
Vol 202 (7) ◽  
pp. 845-853
Author(s):  
J. Brackenbury

The kinematics of locomotion was investigated in the aquatic larvae of Dixella aestivalis and Hydrobius fuscipes with the aid of high-speed video recordings. Both insects are able to skate on the surface of the water using the dorso-apical tracheal gill as an adhesive organ or ‘foot’. Progress relies on the variable adhesion of the foot between ‘slide’ and ‘hold’ periods of the locomotory cycle. The flexural body movements underlying skating in D. aestivalis can be derived directly from the figure-of-eight swimming mechanism used in underwater swimming. The latter is shown to be similar to figure-of-eight swimming in chironomid larvae. This study shows how the deployment of a ‘foot’ enables simple side-to-side flexural movements of the body to be converted into effective locomotion at the air-water interface.


2020 ◽  
Vol 60 (7) ◽  
pp. 875-888 ◽  
Author(s):  
S. E. Rigby ◽  
R. Knighton ◽  
S. D. Clarke ◽  
A. Tyas

2016 ◽  
Vol 12 (3) ◽  
pp. 20160011 ◽  
Author(s):  
David A. Penning ◽  
Baxter Sawvel ◽  
Brad R. Moon

To survive, organisms must avoid predation and acquire nutrients and energy. Sensory systems must correctly differentiate between potential predators and prey, and elicit behaviours that adjust distances accordingly. For snakes, strikes can serve both purposes. Vipers are thought to have the fastest strikes among snakes. However, strike performance has been measured in very few species, especially non-vipers. We measured defensive strike performance in harmless Texas ratsnakes and two species of vipers, western cottonmouths and western diamond-backed rattlesnakes, using high-speed video recordings. We show that ratsnake strike performance matches or exceeds that of vipers. In contrast with the literature over the past century, vipers do not represent the pinnacle of strike performance in snakes. Both harmless and venomous snakes can strike with very high accelerations that have two key consequences: the accelerations exceed values that can cause loss of consciousness in other animals, such as the accelerations experienced by jet pilots during extreme manoeuvres, and they make the strikes faster than the sensory and motor responses of mammalian prey and predators. Both harmless and venomous snakes can strike faster than the blink of an eye and often reach a target before it can move.


2000 ◽  
Vol 203 (14) ◽  
pp. 2159-2170 ◽  
Author(s):  
M. Verstappen ◽  
P. Aerts ◽  
R. Van Damme

The inter-limb kinematic patterns of walking, running and out-of-phase hopping in black-billed magpies (Pica pica) were studied using high-speed video recordings. The flexion/extension patterns of the joints were similar between the gait types, suggesting that the within-leg control of the angular excursions is similar. This result is further supported by the fact that running and hopping are alternative gaits at speeds higher than walking; however, magpies show a preference for hopping. Moreover, only small differences occur between the kinematic patterns of the two limbs during out-of-phase hopping, during which the legs are believed to have different functions. The hindlimb kinematic patterns of magpies are like those of other flying and more terrestrial bird species; however, striking differences are found in comparison with humans at the level of the internal angles. This is probably due to the differences in the morphology and configuration of their legs.


2013 ◽  
Vol 464 ◽  
pp. 416-419
Author(s):  
Li Zhao ◽  
Hua Ying Shu

The thesis first analyzes the concept of mobile payment, and then it makes a distinction between remote payment and near field payment. In addition to that, it infers the development of global mobile payment, which involves the users and the market size. Secondly it probes into Chinas rapid development of mobile internet economy, whose 3G network and smart phones provides high-speed mobile Internet and visual, convenient interface for mobile payment. Thirdly, harmonization of standards of mobile payment will help create industry chain parties openness, cooperation and win-win situation and promote mobile payment intensive and large-scale development process. In the end, it probes into the win-win business model for the telecom operators and financial institutions: Telecom operators will lease SIM card space to obtain revenue and financial institutions will get more fee income.


2016 ◽  
Vol 78 (4) ◽  
Author(s):  
Aqbal Hafeez Ariffin ◽  
Mohd Syazwan Solah ◽  
Azhar Hamzah ◽  
Mohd Hafzi Md Isa ◽  
Zulhaidi Mohd Jawi ◽  
...  

Motorcyclist constituted more than 50% of road deaths in Malaysia. Statistics showed that most fatal motorcyclist crashes involved passenger cars: with sideswipe or side impact reported to be the most frequent crash configurations. Many related studies have been performed to completely understand such motorcycle crashes which resulted in many safety inventions. These include installation of airbag onto motorcycle to study its effectiveness in potentially reducing motorcyclist’s injury. However, previous related studies known mainly dealt airbag’s effectiveness for large cc motorcycles. Hence, an exploratory study was conducted to study airbag’s suitability in mitigating rider’s injury during collision for motorcycle with low engine capacity (cc). Two different full-scale crash tests of motorcycle (with and without mounted airbag) side-impacting passenger car were conducted in accordance to ISO 13232. The test results in terms of high-speed video recordings (crash kinematics), motorcycle damage profiles and dummy injuries were analysed and discussed. It could be suggested from the results obtained that an airbag system for low cc motorcycle is feasible and further study is needed for better airbag concept and design which could reduce motorcyclist injury during collision.


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