|
|
Factors affecting predators' search for cryptic prey
Kuncová, Aneta ; Exnerová, Alice (advisor) ; Hotová Svádová, Kateřina (referee)
This thesis is focused on selected mechanisms, which affect predators' search for cryptic prey. The purpose was to compare information concerning existence, content, duration and circumstances related to formation of a visual search image and it's existence in relation to other sensual modalities. The search image research was carried on many animal species, both invertebrates and vertebrates, with most experiments being carried on birds, specifically blue jays (Cyanocitta cristata) and pidgeons (Columba livia). There are many alternative explanations for the results of those experiments, either negating the search image's existence or just adding to it. The majority of studies agrees upon the existence of search image, but the circumstances of it's formation, as well as its duration and content are specific both for different kinds of predators (depending on their foraging strategies) and different kinds of prey. The differences can also be found in the search image's duration, depending on 5 predator's foraging strategy and encounter frequency with target prey. A decrease in this frequency results in disappearance of search image for the given prey. The experiments also show that the information content concerning the searched target, an essential part of the search image, depends on the prey's...
|
|
|
Factors affecting predators' search for cryptic prey
Kuncová, Aneta ; Exnerová, Alice (advisor) ; Hotová Svádová, Kateřina (referee)
This thesis is focused on selected mechanisms, which affect predators' search for cryptic prey. The purpose was to compare information concerning existence, content, duration and circumstances related to formation of a visual search image and it's existence in relation to other sensual modalities. The search image research was carried on many animal species, both invertebrates and vertebrates, with most experiments being carried on birds, specifically blue jays (Cyanocitta cristata) and pidgeons (Columba livia). There are many alternative explanations for the results of those experiments, either negating the search image's existence or just adding to it. The majority of studies agrees upon the existence of search image, but the circumstances of it's formation, as well as its duration and content are specific both for different kinds of predators (depending on their foraging strategies) and different kinds of prey. The differences can also be found in the search image's duration, depending on 5 predator's foraging strategy and encounter frequency with target prey. A decrease in this frequency results in disappearance of search image for the given prey. The experiments also show that the information content concerning the searched target, an essential part of the search image, depends on the prey's...
|
|
|
Antipredatory function of flash display in Heteroptera (case of Coreus marginatus)
Pipek, Pavel ; Exnerová, Alice (advisor) ; Kleisner, Karel (referee)
1 Abstract Aim of the present study was to test antipredatory function of fulguration (or flash display), which means sudden exposition of conspicous body part on otherwise cryptic animal during escape. Adult squash bugs (Coreus marginatus; Heteroptera) were used as model prey, while as model predator served two species of passerine birds - blue tit (Cyanistes caerulus) and great tit (Parus major). Three approaches were undertaken. Test of palatability should have assessed the efficiency of squash bug chemical defence against bird predators. Experiment was carried out in experimental cage without interference of experimenter and without occurrence of fulguration. The results show that chemical defense of squash bug is less efficient than defense of other species of true bugs (Pyrrhocoris apterus, Graphosoma lineatum) and that the efficiency differs between two generations of squash bugs. In the test of efficiency of fulguration, the prey was forced by experimenter to fly in response to bird attack. Blue tits attacked the immobile prey more often than the flying and fulgurating one, but the same relation wasn't significant with great tits. The latencies of birds' returns to the bugs that landed after fulguration wasn't influenced by colour of the bugs' abdomen. Third experiment consisted of computer...
|
|
|
Effect of the search image on the lizard ability to reveal a Batesian mimic
BENEŠ, Josef
The effect of the search image on the ability of hand reared skinks (Chalcides sexlineatus) to reveal a "fake" Batesian mimic was tested with respect to their previous experience with palatable experimental prey (Guyana spotted cockroach Blaptica dubia) which served as a motivational prey as well as midsized mealworm beetle larvae (Tenebrio molitor). The red firebug (Pyrrhocoris apterus) was used as an aposematic model.
|
|
| |
guest ::
