The effect of apparent predation risk on the respiratory behavior of the Florida gar (Lepisosteus platyrhincus)

1986 ◽  
Vol 64 (10) ◽  
pp. 2133-2136 ◽  
Author(s):  
Roger S. Smith ◽  
Donald L. Kramer
Keyword(s):  
Gas Exchange ◽  
Predation Risk ◽  
Ecological Factors ◽  
Air Breathing ◽  
Great Blue Heron ◽  
Respiratory Behavior

The interbreath interval for aerial and aquatic ventilation was determined for seven Florida gars (Lepisosteus platyrhincus, Pisces, Lepisosteidae) before, during, and after exposure to the simulated threat of predation by a mounted great blue heron (Ardea herodius, Aves, Ardeidae). During exposure to the heron, air-breath interval increased by 118% while water-breath interval decreased by 13% as compared with the pre-heron period. This provides evidence that ecological factors not directly involved in the physiology of gas exchange can influence respiratory partitioning in fishes. It also supports the hypothesis that retention of water-breathing capacity in air-breathing fish can reduce the risk of aerial predation in these species.

The effect of swimming depth on respiratory behavior of the honey gourami, Colisa chuna (Pisces, Belontiidae)

1986 ◽  
Vol 64 (9) ◽  
pp. 1893-1896 ◽  
Author(s):  
David J. Bevan ◽  
Donald L. Kramer
Keyword(s):  
Gas Exchange ◽  
Significant Cost ◽  
Air Breathing ◽  
Adaptive Changes ◽  
Travel Costs ◽  
Feeding Sites ◽  
Swimming Depth ◽  
Respiratory Behavior

We tested the hypothesis that fish capable of bimodal respiration would respond to the increased travel costs of surfacing by decreasing their frequency of air breathing. Honey gouramis were permitted to move freely in a 220 cm deep aquarium, but their preferred depths were manipulated by changing the location of shelter and feeding sites. With increased depth the interval between air breaths increased. This supports the argument that travel to and from the surface is a significant cost for air-breathing fish. It provides evidence that respiratory behavior can be affected by factors not directly involved in the physiology of gas exchange. Furthermore, it suggests that retention of water-breathing capacity in air-breathing species may reduce the costs of breathing through adaptive changes in partitioning.

Vasculature of the Gas-Exchange Organs in Air-Breathing Brachyurans

1990 ◽  
Vol 63 (1) ◽  
pp. 117-139 ◽  
Author(s):  
Peter Greenaway ◽  
Caroline Farrelly
Keyword(s):  
Gas Exchange ◽  
Air Breathing

Respiration in the African Lungfish Protopterus Aethiopicus

1968 ◽  
Vol 49 (2) ◽  
pp. 437-452 ◽  
Author(s):  
CLAUDE LENFANT ◽  
KJELL JOHANSEN
Keyword(s):  
Gas Exchange ◽  
Haemoglobin Concentration ◽  
Temperature Shift ◽  
Mean Value ◽  
Gas Analysis ◽  
Air Exposure ◽  
Air Breathing ◽  
African Lungfish ◽  
High Degree ◽  
Protopterus Aethiopicus

1. Respiratory properties of blood and pattern of aerial and aquatic breathing and gas exchange have been studied in the African lungfish, Protopterus aethiopicus. 2. The mean value for haematocrit was 25%. Haemoglobin concentration was 6.2 g% and O2 capacity 6.8 vol. %. 3. The affinity of haemoglobin for O2 was high. P50 was 10 mm. Hg at PCOCO2, 6 mm. Hg and 25 °C. The Bohr effect was smaller than for the Australian lungfish, Neoceratodus, but exceeded that for the South American lungfish, Lepidosiren. The O2 affinity showed a larger temperature shift in Protopterus than Neoceratodus. 4. The CO2 combining power and the over-all buffering capacity of the blood exceeded values for the other lungfishes. 5. Both aerial and aquatic breathing showed a labile frequency. Air exposure elicited a marked increase in the rate of air breathing. 6. When resting in aerated water, air breathing accounted for about 90% of the O2 absorption. Aquatic gas exchange with gills and skin was 2.5 times more effective than pulmonary gas exchange in removing CO2. The low gas-exchange ratio for the lung diminished further in the interval between breaths. 7. Protopterus showed respiratory independence and a maintained O2 uptake until the ambient O2 and CO2 tensions were 85 and 35 mm. Hg respectively. A further reduction in O2 tension caused an abrupt fall in the oxygen uptake. 8. Gas analysis of blood samples drawn from unanaesthetized, free-swimming fishes attested to the important role of the lung in gas exchange and the high degree of functional separation in the circulation of oxygenated and deoxygenated blood.

scholarly journals The interactive effects of competition and predation risk on dispersal in an insect

2014 ◽  
Vol 10 (6) ◽  
pp. 20140287 ◽  
Author(s):  
Celina B. Baines ◽  
Shannon J. McCauley ◽  
Locke Rowe
Keyword(s):  
Predation Risk ◽  
Intraspecific Competition ◽  
Aquatic Insects ◽  
Ecological Factors ◽  
Factorial Experiment ◽  
Interactive Effects ◽  
Factorial Experiments ◽  
Evolutionary Processes ◽  
Factors Affecting ◽  
Ecological Conditions

Dispersal dynamics have significant consequences for ecological and evolutionary processes. Previous work has demonstrated that dispersal can be context-dependent. However, factors affecting dispersal are typically considered in isolation, despite the probability that individuals make dispersal decisions in response to multiple, possibly interacting factors. We examined whether two ecological factors, predation risk and intraspecific competition, have interactive effects on dispersal dynamics. We performed a factorial experiment in mesocosms using backswimmers ( Notonecta undulata ), flight-capable, semi-aquatic insects. Emigration rates increased with density, and increased with predation risk at intermediate densities; however, predation had minimal effects on emigration at high and low densities. Our results indicate that factorial experiments may be required to understand dispersal dynamics under realistic ecological conditions.

Gas exchange and its control in non-steady-state systems: the consequences of evolution from water to air breathing in the vertebrates

1988 ◽  
Vol 66 (1) ◽  
pp. 109-123 ◽  
Author(s):  
G. Shelton ◽  
P. C. Croghan
Keyword(s):  
Steady State ◽  
Gas Exchange ◽  
Dynamic Models ◽  
Continuous Process ◽  
Circulatory System ◽  
Lung Ventilation ◽  
Burst Duration ◽  
Air Breathing ◽  
Arterial Blood ◽  
Dissociation Curves

Control of breathing and gas exchange has been extensively investigated in unimodal animals, particularly mammals, in which ventilation is characteristically a regular and continuous process and gas exchange approximates to a steady-state system. Both static and dynamic models have been developed in control-theory analyses. Similar analyses are possible in unimodal fish, though few have been carried out. Control in bimodal animals, such as air-breathing fish and amphibians, is more difficult to understand and model. The evolutionary change from water to air breathing in vertebrates involves not only the adjustment of many control processes but also the development, in the early stages, of non steady states in gas exchangers, blood, and tissues. A simple control-system model, differing from mammalian counterparts in its greater emphasis on storage functions and its intermittently activated controller, is described for two suggested stages in the evolution of air breathing. The first of these stages is air gulping, in which a fixed and rather brief pattern of air breathing is activated by internal signals generated as a result of the inadequacy of the gills to provide sufficient oxygen for tissue metabolism. The second stage is that of burst breathing, in which lung ventilation is both begun and ended by internal signals so that burst duration is variable. The effects of adjusting parameters on variables of evolutionary importance, such as dive duration, burst duration, store renewal, and metabolic rate, can be examined in these two versions of the model. Refinements to incorporate arterial and venous compartments in the circulatory system, the shunting of venous and arterial blood streams in the heart, realistic oxygen dissociation curves, controller inputs from a wider range of sources, and the capacity to respond to some conditions with changes in ventilation rate as well as in burst and dive durations, are being developed. They should make the complex, non-steady-state interactions between gas exchangers, circulating blood, and tissues easier to understand and indicate the likely steps toward the evolution of steady-state systems seen in birds and mammals.

Differential effects of predation risk and competition over vigilance variables and feeding success in Eurasian siskins (Carduelis spinus)

Behaviour ◽  
2013 ◽  
Vol 150 (14) ◽  
pp. 1665-1687 ◽  
Author(s):  
Jordi Pascual ◽  
Juan Carlos Senar
Keyword(s):  
Food Intake ◽  
Predation Risk ◽  
Foraging Behaviour ◽  
Interference Competition ◽  
Ecological Factors ◽  
Intake Rate ◽  
Similar Length ◽  
Feeding Success ◽  
High Predation ◽  
Food Intake Rate

Many investigations have studied the effects of predation risk and competition over vigilance and feeding success, but they have proven to be difficult to discriminate. Moreover, none of the studies that have avoided the confusion has considered all the vigilance variables, food intake rate and time spent in the foraging patch. In this study, we designed an experiment with Eurasian siskinsCarduelis spinusforaging on three bird table feeders: one with low predation risk and competition, one with low predation risk and high competition and one with high predation risk and intermediate competition. Birds responded to increasing interference competition by increasing mean scan durations (probably due to the birds having to be vigilant for both other flock members and predators) and maintaining the length of mean inter-scan durations, while they responded to increasing predation risk by reducing mean inter-scan durations (probably in order to detect the predator sooner) while maintaining similar length of mean scan durations. Birds were often ejected from the feeder or departed because of disturbances, so time spent on feeders was reduced both because of competition and predation risk. Pecking rates were affected by competition but not by predation risk. Our results clearly show that birds vigilance strategy while foraging might be very different when they are mainly concerned with scanning for predators or when they primarily monitor competing flock companions. In addition, they stress the importance of recording all the vigilance and feeding variables when studying the effect of ecological factors over the foraging behaviour of birds.

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