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Reproductive strategy of the termite Silvestritermes minutus and its consequences for the life history and ecological succes
Křivánek, Jan ; Hanus, Robert (advisor) ; Klimeš, Petr (referee)
Mixed reproductive strategies are unique modes of reproduction, in which the organisms alternate sexual and asexual offspring production to benefit from both processes. In termites, such a strategy was first described in 2009 and dubbed Asexual Queen Succession (AQS). Reproduction in most termite species is based on a presence of one pair of long-lived reproductives, the primary king and queen, producing in a lifelong strict monogamy all other colony members using classical sexual processes. In a few rare species, the primary queen has been observed to be replaced at some stage of colony development by a harem of neotenic queens. These arise from unfertilized eggs via thelytokous parthenogenesis and reproduce with the founding king. While the workers, soldiers and winged dispersing reproductives remain to be produced sexually, new generations of parthenogenetic neotenic queens appear in the colony to supplement the harem. As long as the founding king is alive, the genetic constitution of most offspring remains identical as if the founding queen would still be alive, while the overall fecundity of the colony increases thanks to the large number of queens. At the same time, the continuous renewal of the harem by new parthenogens offers a virtually unlimited lifespan extension to the colony. In my...
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Circumstances surrounding early parenthood in the Czech Republic: Life strategies of pregnant women and mothers under the age of 20
Kyzlinková, Renáta ; Rychtaříková, Jitka (advisor) ; Kocourková, Jiřina (referee) ; Kuchařová, Věra (referee)
CIRCUMSTANCES SURROUNDING EARLY PARENTHOOD IN THE CZECH REPUBLIC: LIFE STRATEGIES OF PREGNANT WOMEN AND MOTHERS UNDER THE AGE OF 20 Abstract The data gathered in the qualitative study by 58 semi-structured interviews with pregnant teenage girls or teenage mothers were used to describe relatively large scope of life circumstances connected to early pregnancies. The author examines what was the reason for becoming pregnant, how the teenagers' decision about how to respond to getting pregnant was made and how their life strategies changed under the pressure of this unpredictable event. Studying sexual behavior of adolescent mothers the author placed emphasis on partners' communication connected with first sexual intercourse and the increased risk of sexual abuse among the observed population. Furthermore, the role of "sexual socialization" in the family of origin was discussed. Concerning decision-making process- "keeping the baby or not", the main emphasis was placed on the social support networks and their influence on pregnant women's decisions. Very important issue analyzed in this part of the study is phenomenon of "wishing to have a baby". Another topics covered are the family formation process and housing conditions after opting for motherhood, in particular, the importance of marriage and the partner's...
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Alternative reproductive strategies and sexual selection in barn swallow Hirundo rustica
Michálková, Romana ; Albrecht, Tomáš (advisor) ; Sedláček, Ondřej (referee) ; Svobodová, Jana (referee)
Molecular techniques have revealed that avian mating system is more diverse and complex than previously thought. Both males and females can use alternative reproductive tactics to increase their fitness. Here, we have determined the prevalence of conspecific brood parasitism (CBP, 22% of nests), quasi-parasitism (QP, 6.5% of nests) and extra-pair paternity (EPP, 51.2% of nests) in European subspecies of barn swallow (Hirundo rustica rustica). In contrast to EPP and CBP, QP is rare and has been described in only a few bird species. Our data indicate nonrandom QP patterns, suggesting that this tactic can be considered a third alternative reproductive strategy, alongside CBP and EPP. Sexual ornaments are usually assumed to evolve as condition-dependent signals of individual quality. In this context, a positive correlation between the expression of ornamental traits and survival, is expected. Evolutionary theory predicts that females seek extra-pair fertilizations from high-quality (more ornamented) males and EPP has consequently been proposed as a principal protagonist in the evolution of male secondary sexual traits, however empirical evidence in support of the assertion is relatively scarce. Despite decades of research into the role of EPP in sexual selection, the potential fitness advantages for...
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Hierarchy and human behavior. BDSM as an alternative sexual behaviour.
Jozífková, Eva ; Weiss, Petr (advisor) ; Bob, Petr (referee) ; Zvěřina, Jaroslav (referee)
Preferences for sexual arousal by overstated dominance and submission in sex is categorized as F65.5, sadomasochism, according to ICD, but this behaviour is called BDSM among the general public. The ground of these preferences could be ultimately biological. These preferences reflect behavioural strategy which enables to gain higher reproductive success. Men and women who were sexually aroused by a submissive partner had more male relatives than men and women with other preferences. Contrary to the women, the dominant men reported themselves as more attractive. Women who were aroused by a higher-ranking partner considered themselves more attractive. Sons of couples in which was hierarchical disparity had more siblings than sons of "equal" couples or couples with no hierarchical disparity. Daughters of hierarchically disparate couples had more brothers than daughters of "both dominant" partners. Concurrently, number and gender of offspring as well as self- reported attractiveness are likely to be criteria of the reproductive success in humans. It is also interesting that hierarchically disparate couples, without regard to gender of higher-ranking partner, reached higher reproductive success than "equal" couples. Individuals who preferred higher- or lower-ranking partner were also aroused by...
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Reproductive strategy of the termite Silvestritermes minutus and its consequences for the life history and ecological succes
Křivánek, Jan ; Hanus, Robert (advisor) ; Klimeš, Petr (referee)
Mixed reproductive strategies are unique modes of reproduction, in which the organisms alternate sexual and asexual offspring production to benefit from both processes. In termites, such a strategy was first described in 2009 and dubbed Asexual Queen Succession (AQS). Reproduction in most termite species is based on a presence of one pair of long-lived reproductives, the primary king and queen, producing in a lifelong strict monogamy all other colony members using classical sexual processes. In a few rare species, the primary queen has been observed to be replaced at some stage of colony development by a harem of neotenic queens. These arise from unfertilized eggs via thelytokous parthenogenesis and reproduce with the founding king. While the workers, soldiers and winged dispersing reproductives remain to be produced sexually, new generations of parthenogenetic neotenic queens appear in the colony to supplement the harem. As long as the founding king is alive, the genetic constitution of most offspring remains identical as if the founding queen would still be alive, while the overall fecundity of the colony increases thanks to the large number of queens. At the same time, the continuous renewal of the harem by new parthenogens offers a virtually unlimited lifespan extension to the colony. In my...
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Hierarchy and human behavior. BDSM as an alternative sexual behaviour.
Jozífková, Eva ; Weiss, Petr (advisor) ; Bob, Petr (referee) ; Zvěřina, Jaroslav (referee)
Preferences for sexual arousal by overstated dominance and submission in sex is categorized as F65.5, sadomasochism, according to ICD, but this behaviour is called BDSM among the general public. The ground of these preferences could be ultimately biological. These preferences reflect behavioural strategy which enables to gain higher reproductive success. Men and women who were sexually aroused by a submissive partner had more male relatives than men and women with other preferences. Contrary to the women, the dominant men reported themselves as more attractive. Women who were aroused by a higher-ranking partner considered themselves more attractive. Sons of couples in which was hierarchical disparity had more siblings than sons of "equal" couples or couples with no hierarchical disparity. Daughters of hierarchically disparate couples had more brothers than daughters of "both dominant" partners. Concurrently, number and gender of offspring as well as self- reported attractiveness are likely to be criteria of the reproductive success in humans. It is also interesting that hierarchically disparate couples, without regard to gender of higher-ranking partner, reached higher reproductive success than "equal" couples. Individuals who preferred higher- or lower-ranking partner were also aroused by...
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New case of mixed reproductive strategy and its adaptive significance in the neotropical termite Silvestritermes minutus (Termitidae: Syntermitinae)
Křivánek, Jan ; Hanus, Robert (advisor) ; Žďárek, Jan (referee)
Thanks to the progress in genetic methods in population ecology, many critical discoveries were recently made in the field of reproductive strategies of social insect. Among them is the description of mixed reproductive strategies, combining advantages of sexual reproduction with thelytokous parthenogenesis. The queens of such species produce sterile castes through classical sexual process from fertilized eggs, while future queens develop asexually from unfertilized eggs. This original breeding system was first described in several genera of ants, but it was found very recently, that it is not restricted to social Hymenoptera, since it has been identified also in the phylogenetically remote eusocial clade of termites. Switching between the sexual process and thelytokous parthenogenesis, now known as Asexual Queen Succession (AQS), which enables a continuity of genetically almost identical queen generations after the death of the founding primary queen, was first reported only in one genus of lower termites, i.e. Reticulitermes. Recently, our research group participated at the identification of AQS in four other species from two subfamilies in higher termites. One of these species is Silvestritermes minutus. This species is locally abundant in French Guiana and lives in small, well shaped nests on...
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Voluntary and involuntary childlessness: From relatively high birth-rate to absence of children
Hrabánková, Anežka ; Balon, Jan (advisor) ; Pašková, Miroslava (referee)
The aim of presented bachelor work is the problem of progressive reduction of the birth rate from its beginning up to present , when the phenomenon of childlessness is occurred relatively frequently. Intended childlessness begins to be the rightful alternative of living or reproductive strategy. At the same time the number of couples unable to deliver baby from the biological causes continues to increase. These facts weakens the position of parenthood. Subsequently the parenthood is not viewed by the society as a natural and self-evident phenomenon as it was formerly. My work also deals with the phenomenon of voluntary and involuntary childlessness, their extent in the Czech society is evaluated. The view of the society and the childless people themselves concerning this problem is also mentioned.
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Circumstances surrounding early parenthood in the Czech Republic: Life strategies of pregnant women and mothers under the age of 20
Kyzlinková, Renáta ; Rychtaříková, Jitka (advisor) ; Kocourková, Jiřina (referee) ; Kuchařová, Věra (referee)
CIRCUMSTANCES SURROUNDING EARLY PARENTHOOD IN THE CZECH REPUBLIC: LIFE STRATEGIES OF PREGNANT WOMEN AND MOTHERS UNDER THE AGE OF 20 Abstract The data gathered in the qualitative study by 58 semi-structured interviews with pregnant teenage girls or teenage mothers were used to describe relatively large scope of life circumstances connected to early pregnancies. The author examines what was the reason for becoming pregnant, how the teenagers' decision about how to respond to getting pregnant was made and how their life strategies changed under the pressure of this unpredictable event. Studying sexual behavior of adolescent mothers the author placed emphasis on partners' communication connected with first sexual intercourse and the increased risk of sexual abuse among the observed population. Furthermore, the role of "sexual socialization" in the family of origin was discussed. Concerning decision-making process- "keeping the baby or not", the main emphasis was placed on the social support networks and their influence on pregnant women's decisions. Very important issue analyzed in this part of the study is phenomenon of "wishing to have a baby". Another topics covered are the family formation process and housing conditions after opting for motherhood, in particular, the importance of marriage and the partner's...
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