Eusocial insects evolved a sophisticated intraspecific communication, dominated by chemical signals, the pheromones. Termites (Isoptera) represent an excellent example in this respect, having a wide range of pheromones, such as trail-following, sex-pairing, alarm, and other pheromones. It is especially the former category of pheromones which is ubiquitous in termites and which was chemically characterized in many taxa across termite phylogeny. This allowed phylogenetic reconstruction of the chemical diversity of trail- following pheromones and calls for searching of evolutionary patterns of the sensitivity to these pheromones in various lineages across the tree of life, including the search for evolutionary scenario of the emergence of specific olfactory receptor proteins. In most species, the trail-following pheromones are represented by mono-, di- and tri-unsaturated fatty alcohols (3Z)-dodec-3-en-1-ol (DE), (3Z,6Z)-dodeca-3,6-dien-1-ol (DDE), and (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol (DTE). My overall aim in this thesis was to contribute to the understanding of the evolution of olfactory detection of C12 fatty alcohol trail-following pheromones in termites. More specifically, my question was whether evolutionarily more basal clades (Kalotermes flavicollis and Neotermes cubanus from the family...

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2007. / Honeybee queens typically inhibit the reproductive development of workers in the colony. However, African, Apis mellifera scutellata, honeybee queens seem to have little effect on neighbouring A. m. capensis honeybee workers as is evident in the huge losses of African honeybee colonies due to the invasion by ‘social parasitic’ Cape honeybees (pseudoclones). Certain factors; such as queen and brood presence, the level of colony defence and food availability may render host colonies more vulnerable to invasion by the Cape worker honeybees. In this study host African colonies were split to determine whether a “window of opportunity” existed for Cape honeybee infiltration and thus critical to the capensis problem. Nine African colonies were infected with native and pseudoclone Cape workers over different time periods; before, during and after splitting (treatments). I measured survival rates, as well as reproductive and pheromone development of introduced workers. The effect of brood pheromones on Cape worker reproduction was also examined. Approximately 70% of all workers were removed within 72 hours, a critical period to avoid detection by Cape workers. Queen absence significantly affected the success rate of intrusion and establishment by Cape honeybee workers (GLZ; Wald χ² = 4.49, df = 1, P = 0.033). 21% of 21-day old pseudoclones survived African queenless colonies and only 6% queenright colonies. Native Cape workers showed no difference in survival rates between African queenless (12%) and queenright (11%) colonies. Looking at introduction time, considerably more pseudoclone honeybee workers survived in treatment 1 than did native Cape honeybee workers while for treatment 3 the converse was true. These data show no obvious ‘window of opportunity’ surrounding the swarming process promoting Cape honeybee infiltration and establishment of African honeybee colonies, however the period immediately prior to colony fission represents the best opportunity for invasion by pseudoclones. As for ovary and mandibular gland secretion development, all surviving pseudoclones, irrespective of A. m. scutellata queen presence, fully developed their ovaries and concomitantly produced a mandibular gland secretion dominated by 9- oxo-2-decenoic acid (9ODA). Native Cape workers showed low levels of ovary development in queenright host colonies (8-17%) but this was not true for queenless colonies, with all but one worker developing their ovaries when introduced during and after splitting. Only 40% of native Cape workers introduced before splitting developed their ovaries suggesting that queen pheromones in the three days before splitting retarded ovary development in native Cape workers. These data strengthens the suggestion that the pseudoclone honeybee workers have advanced along the queen-worker developmental continuum. Preliminary studies on brood pheromones, an important factor regulating worker reproduction, indicated that Cape workers reproduce quicker and more eggs when exposed to African brood pheromones, compared to both A. m. capensis brood pheromones and no brood pheromones. Pheromones produced by African larvae therefore do not simply inhibit Cape worker reproductive development but accelerate the commencement of egg laying by these workers. On the whole, host African colonies, especially in the absence of their queen, appear vulnerable surrounding colony fission to invasion by both Cape honeybee worker populations even though there are low survival rates. I conclude that these two Cape honeybee worker populations do differ significantly regarding their reproductive capacity and ability in becoming social parasites.

Digitized from microfiche to pdf format. / Thesis (PhD (Chemistry))--University of Stellenbosch, 1977. / Please refer to full text.

Cette thèse aborde l’écologie et l’évolution des relations qu’entretiennent les orchidées du genre Ophrys avec leurs pollinisateurs. L’approche comparative et la combinaison (i) d’analyses chimiques de phéromones sexuelles et de parfums floraux, (ii) d’analyses génétiques avec des outils moléculaires, et (ii) de tests de comportement réalisés sur les insectes in situ nous ont permis d’éclairer certains aspects méconnus de ces interactions inter-spécifiques. La pollinisation des orchidées du genre Ophrys est assurée par des mâles d'abeilles ou de guêpes solitaires qui opèrent une tentative d’accouplement (pseudocopulation) sur le labelle des fleurs. L'attraction des pollinisateurs est généralement hautement spécifique, régie par un mimétisme des signaux (chimiques, visuels, tactiles) des femelles des espèces d'insectes concernés. Malgré cette spécificité, des hybrides se forment occasionnellement en conditions naturelles, témoignant de la perméabilité partielle des barrières d'isolement reproductif entre espèces. Au cours de ce programme de recherche, nous avons entrepris l’étude des interactions Ophryspollinisateurs en mettant l’accent sur trois aspects spécifiques, à savoir (i) la sélection des caractères floraux par les pollinisateurs, (ii) l'isolement reproductif entre espèces d'Ophrys sympatriques, et enfin (iii) l'évolution des caractères floraux au sein d'un complexe d'espèces-soeurs d'Ophrys associées à différents pollinisateurs. Les principaux résultats de ce travail sont repris ci-dessous, ponctués de références aux articles qui rassemblent l’intégralité des études réalisées.

No description available.

The locomotor activity of the reindeer is separated into a diurnal and a nocturnal phase which, in turn, consists of a  number of short-term activity bursts. The onset and termination  of diurnal and nocturnal activity are largely in synchrony  with sunrise and sunset. Since the diurnal phase is  longer, total activity is dependent on the photoperiod. Total  activity as well as the number of activity bursts is greater  in Jùne with continuous daylight than in December with 6  hours daylight. In winter, reindeer spent less time feeding  but more time ruminating and resting *than in summer. Synchronization  between individuals was also greatest in winter. It  is concluded that the described changes in the activity  pattern are due to an endogenous component and that this component  further controls food consumption and energy balance  of the reindeer.  Seasonal variations in behavioural patterns are described.  Several specific rutting behavioürs, sexual and agonostic,  emerge in the male during the prerut and persist until after  the rut. The preorbital gland is enlarged and secretory activity  is evident. The rut is cha'tabterized by the sudden appearance  of an odour in the breath of mature males followed a few  later by a strong odour in the urine. These odours persist for  a short time during the most intense period of rut. The amount  of androgen rizes sharply and reaches peak concentrations in  late September - early October, decreasing thereafter. The  described behavioural cues occur with a certain constancy in  time in concecutive seasons.  A quantification of the amounts of secretory epithelia in preorbital,  interdigital, caudal and tarsal glands reveals that  only the preorbital gland is subjected to any seasonal and  sexual variation. The apocrine epithelium in this gland is  most developed in mature males during the rutting season and  seems to be dependent upon the presence of an elevated androgen  concentration. The tarsal gland is the least developed  gland while the interdigital and caudal glands are more welldeveloped  and structurally complex. Scattered apocrine glands  are only developed on the legs, the ventral body, oral angle  and in the rump patch. / digitalisering@umu

<p>QCR 20161026</p>

Il existe chez D. melanogaster et D. simulans un polymorphisme des hydrocarbures mâles qui pourrait jouer un rôle dans la mise en place d’un isolement sexuel. Le 7-tricosène (7-T; C23:1) et le 7-pentacosène (7-P; C25:1) sont les phéromones principales des mâles. Elles interviennent dans le comportement de cour et varient en fonction des paramètres géoclimatiques. Cette thèse a pour objectif d'étudier le rôle des phéromones mâles sur l’isolement sexuel ainsi que les changements génétiques à l’origine de leur variation et de leur évolution. Un des volets de cette thèse porte sur des aspects physiologiques et comportementaux. Nous avons étudié l'impact de la température sur la synthèse des hydrocarbures mâles et l'influence du rapport 7-T/7-P sur la résistance à la dessiccation et sur la réceptivité des femelles de différentes populations de D. melanogaster et D. simulans. Nous avons observé un isolement sexuel significatif entre des souches 7-T et 7-P de ces deux espèces présentes au laboratoire depuis des décennies, ainsi qu'entre des lignées issues d'une même population soumises à une sélection artificielle. Il apparaît également que les souches synthétisant de grandes quantités de 7-P s’adaptent plus rapidement aux modifications importantes de température. La seconde partie de cette thèse consiste en la détermination et l'étude des gènes d’élongase pouvant être impliqués dans la synthèse du 7-T et du 7-P chez les mâles de D. melanogaster et dans une moindre mesure chez ceux de D. simulans. Les travaux réalisés nous ont permis de mettre en évidence qu’un gène, situé sur le chromosome II, joue un rôle majoritaire dans la synthèse du 7-P. / In D. melanogaster and D. simulans there is a male hydrocarbon polymorphism that may play a role in sexual isolation. The main male pheromones are the 7-tricosene (7-T C23: 1) and the 7-pentacosene (7-P, C25: 1). They are involved in courtship behavior and depend on geo-climatic parameters. The aim of this thesis is to study the role of male pheromones on sexual isolation and to better understand the genetic changes responsible for the variation and the evolution of male pheromones. The first part investigates the plasticity of CHCs in response to temperature and focuses on the role of 7-T and 7-P in resistance to desiccation and in sexual selection in D. melanogaster and D. simulans. In both species there was partial sexual isolation between 7-T and 7-P flies from wild-type laboratory strains and also from lines that have been artificially selected. Males with high levels of 7-P seemed to modify their CHCs profiles more quickly in response to temperature changes. The second part is the identification of elongase genes that might be involved in the synthesis of 7-T and 7-P in D. melanogaster and D. simulans males. A gene, located on chromosome II, could play a major role in the synthesis of 7-P in D. melanogaster.

O objetivo do presente trabalho foi investigar a relação do núcleo pré-mamilar ventral (PMV): 1) na regulação do sistema reprodutivo em fêmeas, 2) como mediador dos efeitos da leptina e 3) na resposta à estimulação feromonal. Para tanto, induzimos lesão bilateral do PMV em ratas. Foi observado que a lesão do PMV promove: alteração no ciclo estral e da histologia ovariana; redução dos níveis de estradiol e LH; e supressão de vias neurais que controlam o eixo reprodutivo. Além disso, a lesão do PMV impediu que a administração central de leptina induzisse secreção de LH durante o jejum. Em outros experimentos, realizados em ratos machos, verificou-se que neurônios que sintetizam óxido nítrico no PMV e no núcleo medial da amígdala são ativados em resposta ao odor de conspecíficos, em especial o de fêmeas. Assim, foi demonstrado que o PMV exerce papel relevante na regulação do sistema reprodutivo e media a ação estimulatória da leptina na secreção do LH. Além disso, o PMV faz parte do circuito neural relacionado com a resposta aos feromônios. / The objective of this study was to assess the role played by the ventral premammillary nucleus (PMV): 1) in the regulation of the female reproductive system, 2) as a mediator of the effects of leptin and 3) in response to pheromonal stimulation. For this purpose, we produced bilateral PMV lesions in female rats. We observed that PMV lesion: disrupted the estrous cycle and altered the number of ovarian antral follicles; reduced the estradiol and LH levels; and suppressed neural pathways that control the reproductive axis. We found that lesions of the PMV blocked leptin stimulation of LH secretion during fasting. In another experiment using male rats, we showed that nitric oxide synthesizing neurons in the PMV and medial nucleus of amygdala are activated by conspecific odors, especially female odors. Thus, we showed that PMV plays an important role in the control of females reproductive system and mediates the stimulatory effects of leptin on LH secretion. Also, PMV is part of the neural circuitry related to pheromonal responses.

A agressão maternal tem como função preservar a vida da prole. O desenvolvimento desse comportamento depende vastamente do reconhecimento do adversário como uma ameaça potencial e esse reconhecimento envolve a detecção de pistas feromonais. O núcleo pré-mamilar ventral (PMv) é um dos principais alvos do núcleo medial da amígdala, que representa o setor amigdalar crítico para o processamento de pistas feromonais. Desta forma, postulamos que possivelmente o PMv seja sensível às pistas feromonais do macho intruso, servindo como uma possível interface para os sistemas neurais envolvidos na agressão maternal. Neste sentido, inicialmente avaliamos o padrão de ativação do PMv, bem como alguns de seus alvos de projeção, durante o comportamento maternal e durante a agressão maternal. Notamos que tanto o PMv como a maioria de seus alvos principais (tais como, o núcleo posterior da amígdala, a parte posterodorsal do núcleo medial da amígdala, a área hipotalâmica lateral tuberal e a parte ventrolateral do núcleo ventromedial) apresentam um aumento significativo na expressão da proteína Fos durante a agressão maternal. Em seguida, avaliamos o papel do PMv na organização neural do comportamento de agressão maternal, em ratas lactantes portadoras de lesões citotóxicas com NMDA do PMv. Os resultados obtidos neste estudo demonstram que as fêmeas lactantes com lesão no PMv não apresentam qualquer alteração nos parâmetros comportamentais relacionados ao comportamento maternal, mas apresentam uma significante diminuição no comportamento agressivo maternal. Observamos ainda, que a lesão citotóxica do PMv resultou numa drástica diminuição da expressão da proteína Fos em alguns sítios de projeção do PMv que se apresentavam mobilizados durante a agressão maternal (tais como a parte ventrolateral do hipotálamo ventromedial, a área hipotalâmica lateral tuberal e o núcleo pré-óptico medial), sugerindo a participação destes sítios neurais como críticos na expressão do comportamento de agressão maternal. / Maternal aggression is critical to preserve the litters from male intruders, and the pheromonal cues from the males are important to drive such responses. The ventral premamillary nucleus (PMv) is one of the main targets of the medial amygdalar nucleus, and is critically involved in processing pheromonal information. In this regard, in the present study, we investigated whether the PMv would work as a putative interface between the pheromonal processing of the male intruder and the neural sites potentially involved in the expression of maternal aggression. First, we analyzed the pattern of Fos expression in dams expressing aggressive maternal behavior, and found a significant increase in Fos levels in the PMv, as well as, in most of its main targets, such as the posterior amygdalar nucleus, the posterodorsal part of the medial amygdalar nucleus, the tuberal nucleus of the lateral hypothalamic area, and the ventrolateral part of the ventromedial nucleus. Next, we examined how NMDA lesions bilaterally placed in the PMv would interfere in maternal aggression, and found that dams bearing those lesions presented a significant reduction in the expression of aggressive behavior, but showed no alterations on the maternal behavior responses. Moreover, we were able to see that PMv lesions resulted in significant drop in Fos expression in selected PMv targets, namely the tuberal nucleus of the lateral hypothalamic area and the ventrolateral part of the ventromedial nucleus, likely to be critically involved in the expression of the maternal aggression. Overall, the present results support the idea that the PMv is seemingly a key site in the network controlling maternal aggression; on one hand, the nucleus is likely to processes pheromonal cues from the intruder male, and, on the other, it conveys this information to sites critically related to the expression of maternal aggression.