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Wing reduction in cockroaches (Blattaria)
Kotyk, Michael ; Kotyková Varadínová, Zuzana (advisor) ; Nedvěd, Oldřich (referee)
My bachelor thesis deals with the wing reduction in cockroaches and the causes of its appearance. Order Blattaria is the insect order with the third highest occurrence of apterous and brachypterous species. Yet still only a minimum of publications were performed to cover this topic. Therefore, I analyse in several chapters both the types of wing reduction as well as generally accepted theories explaining the reasons of its evolution in insects. Then I discuss their relevance in the case of order Blattaria. Namely, ecological theories, regarding interactions of insect and its habitat, and physiological theories, describing life history trade- offs and constrains related to wings. I present examples of species to every theory which are probably concerned. There are also examples of species which maintain the macropterous state, although no longer capable of flight and theories that explain the retention of macroptery. As a part of the thesis I have also included a phylogenetic tree of cockroaches with marked wing condition for each sex, which outlines evolutionary trends of individual groups within the order. Keywords: Blattaria, reduction, macroptery, brachyptery, aptery, habitat, life history trade-offs
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Minor insect groups as pollinators and flower visitors
Jůna, František ; Kotyková Varadínová, Zuzana (advisor) ; Tropek, Robert (referee)
The aim of my bachelor thesis is to review flower-insect interactions in those insect orders which are traditionally recognized as minor groups of insect pollinators. This means Coleoptera, Diptera, Hymenoptera and Lepidoptera orders are excluded. The emphasis is on the occurrence of pollination relationship, but palynivory, nectarivory, flower herbivory and flowers as hunting-site are discussed too. Much of the research is just listing the species which were found on flowers without any deeper study of their relationship with the flower. These non-specified interactions are recognised as flower visitors. Most of this bachelor thesis is about the order of Thrips (Thysanoptera), because of the large number of pollinators in this order. On the other hand many other orders are only mentioned or they even are missing. There is little interaction by some orders, or the interactions are missing or they are unknown. Also fossil flower-insect interactions are mentioned too. Key words Pollination, Thrips, Cockroaches, Lacewings, True bugs, Scorpionflies, Earwigs, Orthoptera, Caddisflies
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Role of wings in reproduction of cockroach Eublaberus distanti (Blattodea: Blaberidae)
Kotyk, Michael ; Kotyková Varadínová, Zuzana (advisor) ; Štys, Pavel (referee)
Regardless the wings and active flight are recognized as one of the most iconic innovations in insects, a great number of their representatives exhibit wing reduction. In many cases only females lose the wings while males not. It is usually believed that lower investments into wings and wing muscles save energy for reproductive gain in females. Cockroaches are the insect order with one of the highest occurrence of forms with reduced wings andspecies exhibiting sexual wing dimorphism, and thus are a good model group for testing the hypotheses concerning the wing reduction. For our experiments we chose macropterous cockroach Eublaberus distanti and manipulated with the length of its wings.Contrary to common assumption, we did not find any significant difference in fecundity between apterous and macropterous females. So we conclude that wing presence or absence has no effect on reproduction success of cockroach females. Surprisingly, we have found out that male wings play a substantial role in the courtship ritual of E. distanti. Our results reveal that partial or complete loss of wings severely decreases reproductive success of E. distanti males compared to macropterous conspecifics. We thus conclude that the reason why cockroach males keep their wings while females not is because of their fundamental role in...
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The role of male external glands in sexual behaviour of insect
Dvořák, Tomáš ; Kotyková Varadínová, Zuzana (advisor) ; Hanus, Robert (referee)
The body of some insect's males is covered by glands, which females are interested in during or after courtship and copulation. Female can palpate this glands or feed on their secretion. My bachelor thesis describes these glands in five orders of insect, where they are known: Zygentoma, Zoraptera, Coleoptera and especially Orthoptera and Blattodea. In the introduction i describe briefly their histology, morphology and ontogeny. But the main part of the work deal with their ethological and ecological function. This glands have four main functions. They can serve to maneuver female into proper position and allow the male to clasp her genitalia. Another function is prolonging of copulation, which enable the male to transfer more sperm. Glands can also provide nutritious secret, through it the male directly affects the female fitness. The last function is simple signal of male quality, which through the production of secret demonstrates his good condition. The role of the glands is often uncertain and their functions are often overlaping.
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Diversity of cockroach mating behaviour (Blattodea: Blaberidae)
Dvořák, Tomáš ; Kotyková Varadínová, Zuzana (advisor) ; Nedvěd, Oldřich (referee)
Mating behaviour of cockroaches is spectacular phenomenon with three different mating patterns traditionally distinguished. The most common and probably ancestral is type A - female climbing. Then it is type B - male climbing and type C - no climbing. Mating type was described in around 30 Blaberidae species. As it is the only cockroach family where all three types are present, it is an interesting model group for studying evolutionary questions. The main goal of the thesis was detail exploration and description of mating sequences in 21 Blaberidae species, 17 of which haven't been examined in this aspect before. An intrageneric diversity in mating patterns (genus Pycnoscelus) was described for the first time. Moreover, in case of P. tenebrigera, it was not possible to assign its mating pattern to any of the three traditional types. Multidimensional statistical analysis and biological interpretation of qualitative behavioural elements revealed two well separated clusters of mating sequensces. Consequently, we propose to distinguish only two types of mating pattern - ancestral type (identical with type A) and derived type. We also discussed the relationship between wing reduction and occurence of derived mating types. Evaluation of quantitative behavioural elements revealed positive correlation between...
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The role of male external glands in sexual behaviour of insect
Dvořák, Tomáš ; Kotyková Varadínová, Zuzana (advisor) ; Hanus, Robert (referee)
The body of some insect's males is covered by glands, which females are interested in during or after courtship and copulation. Female can palpate this glands or feed on their secretion. My bachelor thesis describes these glands in five orders of insect, where they are known: Zygentoma, Zoraptera, Coleoptera and especially Orthoptera and Blattodea. In the introduction i describe briefly their histology, morphology and ontogeny. But the main part of the work deal with their ethological and ecological function. This glands have four main functions. They can serve to maneuver female into proper position and allow the male to clasp her genitalia. Another function is prolonging of copulation, which enable the male to transfer more sperm. Glands can also provide nutritious secret, through it the male directly affects the female fitness. The last function is simple signal of male quality, which through the production of secret demonstrates his good condition. The role of the glands is often uncertain and their functions are often overlaping.
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Chemical aposematism: reactions of predators towards chemical warning signals of prey
Chalušová, Kateřina ; Exnerová, Alice (advisor) ; Kotyková Varadínová, Zuzana (referee)
An aposematism is a type of defence mechanism, by which a prey demonstrates towards predator that it is unpalatable and toxic. The reactions of predators towards chemical warning signals of prey differ due to the quantity and a combination of signals showed by prey, the predator species and its primary orientation. Most of works tested reactions of birds towards gustatory and olfactory stimuli, often in combination with signals from other modalities. Although the birds are predators which orientate primarily visually, olfaction, gustation and chemesthesis significantly helped them with determining unpalatable food. Among other tested predators were fish, amphibians, reptiles, mammals and invertebrates and their reactions towards the same chemicals of prey are noted for comparison. The main chemicals used in the experiments regarding birds were denatonium benzoate (Bitrex), quinin and pyrazines. Predators often showed an aversive behaviour, neophobic reactions, accelerated learning and more effective memorizing of the unpalatable prey if it was presented together with chemical signals. Some of the predators were able to control their toxin intake relative to the amount of toxin ingested or to discriminate between palatable and unpalatable food according to the chemical concentration in it. Key...
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The influence of chemical stimuli on the behaviour of the cockroach Amazonina platystylata (Blattodea: Ectobiidae)
Jůna, František ; Kotyková Varadínová, Zuzana (advisor) ; Nedvěd, Oldřich (referee)
Cockroaches are not considered typical plant pollinators, however, there are some exceptions to this rule. One of them is the South American species Amazonina platystylata, which is known for pollinating a dioecious shrub Clusia blattophila. This clusia is quite abundant on the Nouragues inselberg in French Guyana and is endemic there. In my research I was focused on the plant-animal communication. The aim of this thesis was to find possible behavioural response to the flower scent of clusia or to the compounds of flower scent, as clusia flowers differ in compounds of scent. Male flowers produce acetoin as a major compound. This compound is also found in female flowers but only at lower levels and in the first night of flowering. When acetoin was added to two days old female flowers, the amount of cockroaches' visits in such flowers increased to the same level as observed on male flowers. Until now there were no records about biology of this cockroach species and neither was morphology of their glands described. I have found out that both males and females of A. platystylata have tergal modification on the 7th to 8th tergite; a modification that could be connected to their glands. Evaporation plate on the first tergal shield in A. platystylata is described in this thesis for the first time. Key...
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Role of wings in reproduction of cockroach Eublaberus distanti (Blattodea: Blaberidae)
Kotyk, Michael ; Kotyková Varadínová, Zuzana (advisor) ; Štys, Pavel (referee)
Regardless the wings and active flight are recognized as one of the most iconic innovations in insects, a great number of their representatives exhibit wing reduction. In many cases only females lose the wings while males not. It is usually believed that lower investments into wings and wing muscles save energy for reproductive gain in females. Cockroaches are the insect order with one of the highest occurrence of forms with reduced wings andspecies exhibiting sexual wing dimorphism, and thus are a good model group for testing the hypotheses concerning the wing reduction. For our experiments we chose macropterous cockroach Eublaberus distanti and manipulated with the length of its wings.Contrary to common assumption, we did not find any significant difference in fecundity between apterous and macropterous females. So we conclude that wing presence or absence has no effect on reproduction success of cockroach females. Surprisingly, we have found out that male wings play a substantial role in the courtship ritual of E. distanti. Our results reveal that partial or complete loss of wings severely decreases reproductive success of E. distanti males compared to macropterous conspecifics. We thus conclude that the reason why cockroach males keep their wings while females not is because of their fundamental role in...
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Minor insect groups as pollinators and flower visitors
Jůna, František ; Kotyková Varadínová, Zuzana (advisor) ; Tropek, Robert (referee)
The aim of my bachelor thesis is to review flower-insect interactions in those insect orders which are traditionally recognized as minor groups of insect pollinators. This means Coleoptera, Diptera, Hymenoptera and Lepidoptera orders are excluded. The emphasis is on the occurrence of pollination relationship, but palynivory, nectarivory, flower herbivory and flowers as hunting-site are discussed too. Much of the research is just listing the species which were found on flowers without any deeper study of their relationship with the flower. These non-specified interactions are recognised as flower visitors. Most of this bachelor thesis is about the order of Thrips (Thysanoptera), because of the large number of pollinators in this order. On the other hand many other orders are only mentioned or they even are missing. There is little interaction by some orders, or the interactions are missing or they are unknown. Also fossil flower-insect interactions are mentioned too. Key words Pollination, Thrips, Cockroaches, Lacewings, True bugs, Scorpionflies, Earwigs, Orthoptera, Caddisflies
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