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At least 649 records · Page 36Linked to original sources
PubMed1989

Hand preferences and whole (Galago senegalensis).

The hand preferences in prey capture and whole-body turning biases after prey capture were assessed in 10 lesser bushbabies (Galago senegalensis) in 8 conditions designed to manipulate posture, visibility of prey and angle of reaching. Each subject received 60 trials in each test condition for a total of 480 trials. Seven subjects had a left-hand preference in food reaching, three right and none were ambipreferent. Eight subjects had a left whole-body turning bias, one right and one had no bias. No correlation was found between reach preference and turning bias. Bipedal posture facilitated the use of the dominant hand, whereas other manipulated conditions did not have a significant effect on hand use. A neuraxial arousal system is postulated as mediator of the bipedal effect on hand use.

Animals↗
PubMed1988

Variation in neuromuscular activity during prey capture by trophic specialists and generalists (Pisces: Labridae).

Members of the marine teleost family Labridae are among the most abundant and morphologically diverse fish on coral reefs. A quantitative analysis was conducted of the neuromuscular activity patterns controlling movement of the jaws during prey capture by 4 labrid species ranging from trophic specialists to trophic generalists. A total of more than 800 captures of 3 prey types was analyzed. All 4 species showed significant modulation of electromyographic parameters in response to different prey types. Significant variation was also found between replicate experiments on the same individuals. To obtain valid assessments of interspecific variability, statistical analyses must take into account this potentially high degree of intraspecific variability. By partitioning the variance in a nested analysis of variance, a lack of significant differences in electromyographic parameters between species became apparent. In contrast to the closely related Cichlidae, trophic diversification in the Labridae has not been accompanied by the acquisition of unique neuromuscular activity patterns for prey capture. The dramatic adaptive radiation that has occurred in these 2 families has involved different processes of evolutionary diversification. Neuromuscular stereotypy of labrids may be associated with the lack of structural flexibility in their 'coupled jaw'. Additional study is needed to establish the extent to which labrid radiation into various trophic niches is related to the evolution of specialized morphologies and foraging behaviors.

Animals↗
PubMed1976

Fishing behaviour in Galago crassicaudatus E. Geoffroy, 1812 (Prosimiae; Lorisiformes; Galagidae).

Fishing behaviour was first observed in Galago crassicaudatus. Some of the animals (Maria, Werner, Ilse) was born in the wild, some in captivity in family groups [Welker, 1972]. The colony had been under permanent observation since 1971. The following results were obtained: (1) One animal had to begin with fishing behaviour. (2) The other animals learned it by watching one animal fishing. (3) Animals born in captivity, deceived by the refraction of the water, grasped constantly too high.

Animals↗
PubMed1995

Feeding kinematics of phyllomedusine tree frogs.

Previous studies have demonstrated that the phyllomedusine hylids possess highly protrusible tongues, a derived characteristic within the family Hylidae. In the present study, the kinematics of the feeding behavior of a phyllomedusine species, Pachymedusa dacnicolor, was analyzed using high-speed video (180 frames s-1). Its behavior was compared with that of Hyla cinerea, a species with a weakly protrusible tongue. P. dacnicolor exhibits a faster rate of tongue protraction, a longer gape cycle and more variable feeding kinematics than H. cinerea. In addition, the tongue is used in a unique 'fly-swatter' fashion, to pin the prey to the substratum as the frog completes the lunge. The rapid tongue protraction, extended gape cycle and fly-swatter action may have evolved in response to a diet of large, rapidly moving insects. In addition, several duration variables of the feeding cycle were greater for misses than for captures and drops, which suggests that sensory feedback rather than biomechanics controls gape cycle duration.

Analog-Digital Conversion↗
PubMed2000

Durophagy in sharks: feeding mechanics of the hammerhead Sphyrna tiburo.

This study investigates the motor pattern and head movements during feeding of a durophagus shark, the bonnethead Sphyrna tiburo, using electromyography and simultaneous high-speed video. Sphyrna tiburo feeds almost exclusively on hard-shelled crabs, with shrimp and fish taken occasionally. It captures crabs by ram feeding, then processes or reduces the prey by crushing it between molariform teeth, finally transporting the prey by suction for swallowing. The prey-crushing mechanism is distinct from that of ram or bite capture and suction transport. This crushing mechanism is accomplished by altering the duration of jaw adductor muscle activity and modifying jaw kinematics by the addition of a second jaw-closing phase. In crushing events, motor activity of the jaw adductor muscles continues (biting of the prey occurs as the jaws close and continues after the jaws have closed) throughout a second jaw-closing phase, unlike capture and transport events during which motor activity (biting) ceases at jaw closure. Sphyrna tiburo is able to take advantage of a resource (hard prey) that is not readily available to most sharks by utilizing a suite of durophagous characteristics: molariform teeth, a modified jaw protrusor muscle, altered jaw adductor activity and modified jaw kinematics. Sphyrna tiburo is a specialist feeder on crab prey as demonstrated by the lack of differences in kinematic or motor patterns when offered prey of differing hardness and its apparent lack of ability to modulate its behavior when feeding on other prey. Functional patterns are altered and coupled with modifications in dental and jaw morphology to produce diverse crushing behaviors in elasmobranchs.

Animals↗
PubMed2000

Comparative study of tongue protrusion in three iguanian lizards, Sceloporus undulatus, Pseudotrapelus sinaitus and Chamaeleo jacksonii.

The goal of this study was to investigate the function of the hyolingual muscles used during tongue protraction in iguanian lizards. High-speed videography and nerve-transection techniques were used to study prey capture in the iguanid Sceloporus undulatus, the agamid Pseudoptrapelus sinaitus and the chameleonid Chamaeleo jacksonii. Denervation of the mandibulohyoideus muscle slips had an effect only on P. sinaitus and C. jacksonii, in which tongue protrusion or projection distance was reduced. In C. jacksonii, denervation of the M. mandibulohyoideus completely prevented little hyoid protraction. Denervation of the M. verticalis had no effect on S. undulatus, but reduced tongue protrusion distance in P. sinaitus. Denervation of the accelerator muscle in C. jacksonii inhibited tongue projection completely. The function of the M. mandibulohyoideus and M. verticalis has become increasingly specialized in P. sinaitus and especially in C. jacksonii to allow greater tongue protrusion. The combined results of these treatments suggest that these three groups represent transitional forms, both morphologically and functionally, in the development of a projectile tongue.

Animals↗
PubMed2001

Foraging and prey-search behaviour of small juvenile rainbow trout (Oncorhynchus mykiss) under polarized light.

Several fish species appear to be polarization sensitive, i.e. to be able to discriminate a light source's maximum plane of polarization from any other plane. However, the functional significance of this ability remains unclear. We tested the hypothesis that polarized light improves the prey location ability of free-swimming rainbow trout (Oncorhynchus mykiss) in laboratory aquaria. We found that prey location distances increased while the vertical component of prey location angle decreased under polarized compared with unpolarized (diffuse) illumination. The average frequency distribution of the horizontal component of prey location angle was more bimodal under polarized than unpolarized illumination. These results indicate that polarization sensitivity enhances prey location by juvenile rainbow trout.

Animals↗
PubMed2004

Feeding preference of three lady beetle predators of the hemlock woolly adelgid (Homoptera: Adelgidae).

In a laboratory study, we tested the feeding preferences of three coccinellid predators of hemlock woolly adelgid, Adelges tsugae Annand, an introduced pest of hemlock in the eastern United States. The species tested were Sasajiscymnus tsugae Sasaji & McClure (formerly Pseudoscymnus tsugae) from Japan, Scymnus ningshanensis Yu & Yao from China, and Harmonia axyridis (Pallas), a generalist species introduced from Asia that is currently widespread in eastern hemlock, Tsuga canadensis Carriere, forests. We measured the feeding preference of each beetle species when given the choice of A. tsugae and either 1) Pineus strobi (Hartig) on Pinus strobus L.; 2) Adelges laricis Vallot on Larix decidua Mill.; 3) Adelges cooleyi (Gillette) on Pseudotsuga menziesii (Mirb.) Franco; or 3) Paraprociphilus tessellatus (Fitch) on Alnus serrulata (Ait.) Willd. We evaluated beetle preference for adults, nymphs, and eggs of each prey species. Generally, when adult or nymphal prey stages were compared, S. tsugae preferred A. tsugae adults to P. strobi, A. cooleyi, A. laricis, and P. tessellatus. S. ningshanensis showed less preference between adelgid species, but it did not prefer P. tessellatus nymphs. When preferences for adelgid eggs were assayed, S. tsugae and S. ningshanensis showed no preference between A. tsugae and A. cooleyi or P. strobi, but S. tsugae did prefer A. tsugae to A. laricis. Larvae of S. tsugae were unable to survive on P. tessellatus nymphs. H. axyridis adults readily consumed both A. tsugae and P. tessellatus, but H. axyridis larvae did not complete their life cycle on A. tsugae. Our host range tests suggest that S. ningshanensis and S. tsugae may feed on several species of Adelgidae and that A. tsugae is often preferred.

Animals↗
PubMed2006

Linking patch-use behavior, resource density, and growth expectations in fish.

Optimality theory rests on the assumptions that short-term foraging decisions are driven by variation in environmental quality, and that these decisions have important implications for long-term fitness. These assumptions, however, are rarely tested in a field setting. We linked behavioral foraging decisions in food patches with measures of environmental quality covering larger spatial (resource density) or temporal (growth parameters) scales. In 10 lakes, we measured the food density at which benthic fish give up foraging in experimental food patches (giving-up density, GUD), quantified the biomass of benthic invertebrates, and calculated the maximum individual size (L(infinity)) of bream (Abramis brama L.), a typical benthivore in these lakes. We found positive relationships between resource density and both GUD and L(infinity), and a positive relationship between L(infinity) and GUD. Prey characterized as vulnerable to predation contributed most to the relationships between resource density and either GUD or L(infinity). A path analysis showed that resource density and L(infinity) directly explained 54% and 28%, respectively, of the variation in GUD, whereas 86% of the variation in L(infinity) was explained by resource density, with mostly indirect contribution from GUD. We conclude that the short-term foraging behavior of benthivores matched our expectations based on optimality theory by being positively linked to variables on environmental quality operating at both a larger spatial scale and a longer temporal scale.

Animals↗
PubMedDate not supplied

[Predation of Lymnaea (Galba) truncatula Müller by Zonitoides nitidus Müller (Mollusca Gastropoda Pulmonata) (author's transl)].

Zonitoides nitidus is omnivorous with carnivorous tendancies: the presence of food coming from snails is required for growth of this predator. This snail is not selective for the choice of its preys. Zonitoides cannot be taken for an absolute predator for all growing periods of Lymnaea truncatula: eggs and large snails are not eaten. This species can be cannibal.

Animal Nutritional Physiological Phenomena↗
PubMed2006

[Predation of Orius minutus on Odontothrips loti].

In this paper, a laboratory study was made on the predation of Orius minutus on the 3rd to approximately 4th instar nymphs of Odontothrips loti, and the intraspecific interference within O. minutus. The results showed that the functional responses of adult O. minutus to O. loti nymphs fitted Holling II type equation, i. e., Na = 1.0113N/(1 + 0.04149N) in test tubes, Na = 0. 6777N/(1 + 0.03395N) in Petri dishes, and Na = 0.6417N/(1 + 0.03934N) in enveloped pots. The predation of O. minutus had strong intraspecific interference, and the relationship between predation efficiency and individual interference fitted Hassell model. Under the same spatial conditions, the predation rate of O. minutus was positively related, while its searching efficiency was negatively associated with the prey density. With the increase of the space, the attack rate (a') and maximum predation (Na) of O. minutus decreased, its handling time (Th) increased, while the type of its functional responses to the densities of 3rd to approximately 4th instar O. loti, still fitted Holling II model.

Animals↗
PubMed2006

[Predation of Axinoscymnus cardilobus to Bemisia tabaci].

The laboratory study on the predation of Axinoscymnus cardilobus to Bemisia tabaci showed that the functional response of A. cardilobus to B. tabaci was of Holling' s type II. With the increasing age of B. tabaci, the searching rate of A. cardilobus adult decreased, and its handling time became longer. The searching rate of A. cardilobus larva was increased with its age, and the handling time became shorter. The mutual interference in individual predator could be described by Hassell and Varley equation, and the relationship between predation ratio (E) and natural enemies density (P) was E =0. 5205P(-0 6631.) The predation efficiency (E) of predator varied with environmental temperature, and the effects of the temperature on search rate (a) and handling time ( T ) could be described by a = -0. 0002T(3)+ 0. 0166T(2) - 0. 3492T + 3. 2329 and Th = 4 x 10 (-7) T-( 3) x 10(-5) T(2) + 0.0006T 0.0009, respectively.

Animals↗
PubMed1986

Laboratory evaluation of Gambusia affinis fish as predators of the schistosome-bearing snails Bulinus truncatus.

In this laboratory-based study involving numerous experiments, it was demonstrated that the mosquito fish Gambusia affinis preys effectively upon the schistosome-bearing snail Bulinus truncatus, even in the presence of an alternative source of food. Egg masses and juvenile snails less than or equal to 2 mm in size are preferred. Individual eggs are nibbled, and the tiny snails with fragile shells are swallowed and digested. In the absence of other foods, the fish consume the flesh of snails 3 to 6 mm in size, leaving their empty shells intact. The larger snails are unharmed, but their offspring could be eradicated by the fish under favourable conditions.

Animals↗