689 resultados para virgins queens


Relevância:

10.00% 10.00%

Publicador:

Resumo:

In many eusocial species, queens use pheromones to influence offspring to express worker phenotypes. Although evidence suggests that queen pheromones are honest signals of the queen's reproductive health, here I show that queen's honest signalling can result from ancestral maternal manipulation. I develop a mathematical model to study the coevolution of maternal manipulation, offspring resistance to manipulation and maternal resource allocation. I assume that (i) maternal manipulation causes offspring to be workers against offspring's interests; (ii) offspring can resist at no direct cost, as is thought to be the case with pheromonal manipulation; and (iii) the mother chooses how much resource to allocate to fertility and maternal care. In the coevolution of these traits, I find that maternal care decreases, thereby increasing the benefit that offspring obtain from help, which in the long run eliminates selection for resistance. Consequently, ancestral maternal manipulation yields stable eusociality despite costless resistance. Additionally, ancestral manipulation in the long run becomes honest signalling that induces offspring to help. These results indicate that both eusociality and its commonly associated queen honest signalling can be likely to originate from ancestral manipulation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The annual elimination of large numbers of Argentine ant queens near the advance front of an invasion could be a useful tool for weakening the species’ dispersion and, therefore, limiting its establishment in non-invaded areas. However, before carrying out trials to test the effectiveness of this method it would be essential to have sufficient knowledge of the effect of seasonal dynamics acting on the queens’ densities of the species in order to determine the most favourable period of the year to act. We analyzed the seasonal densities and nest dynamics of Argentine ant queens in an invaded Mediterranean natural ecosystem. We observed that the queens’ density varied depending on the season of the year and that this variation was mainly due to the seasonal dynamics of nest aggregations in winter and ant dispersions in summer. The greatest densities per litre of nest soil were observed in winter (December to March, approximately) and the lowest densities were observed in summer ( June to July). This information is essential for improving current knowledge of the Argentine ant’s biology and developing control methods based on the elimination of queens in invaded natural areas

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The structure of a population can be seen as the result of biotic and abiotic interacting forces. The studies of population characteristics are vital to improve the understanding of ecosystem functioning. In this study, we attempted to answer the two following questions: What are the population structure of Attalea phalerata? and Are there any influence of reproducers presence, canopy openness, declivity, basal area and soil coverage on recruitment of individuals in this population? We distinguished four ontogenetic stages in A. phalerata. Reproducers and virgins were sampled by using 25 plots (400 m²), juveniles and seedlings were sampled in sub-plots (100 m²). We found 2,328 Attalea phalerata individuals per hectare, first two ontogenetic stages accounted for 89.8% of the total, describing a relatively stable population. None of the analyzed factors were affecting the natural regeneration of Attalea phalerata in the fragment. The density and distribution pattern found for the population are probably signs of formation of oligarchic forests, moreover, the species seems to be able to colonize clearings and open areas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

From the Tropic of Capricorn to Equator, the seasonality of domestic cat is known to be absent, i.e., these animals are considered non-seasonal breeders at these regions. We hypothesized that this particularity might have some influence on in vitro embryo production. The aim of this experiment was to determine the percentage of cleavage and morulae and blastocyst formation produced from oocytes recovered from queen ovaries of three distinct status - follicular, luteal or inactive - during two different reproductive seasons experienced by cats in southeast of Brazil (22°53'09" S and 48°26'42" W) - non breeding season (NBS), comprehending January to March; and breeding season (BS), August to October. Thirty queens were neutered. Ovaries were classified according to their status and were sliced in PBS for cumulus oocyte complex (COC) releasing. Grade I COC were washed three times in H-MEM supplemented with BSA, glutamine, sodium pyruvate, cysteine, streptomycin and penicillin. Oocytes were incubated in groups of 20-30 in 400µL of DMEM supplemented with FSH, LH, estradiol, IGF-I and basic fibroblast growth factor under mineral oil for 30 or 36 hours at 38°C in humidified environment of 5% de O2, 5% CO2 and 90% N2. COC were fertilized in Ham's F-10 medium supplemented with BSA, cysteine, pyruvate and streptomycin/penicillin (culture medium) with fresh semen selected through swim up technique. Eighteen hours later, the presumptive zygotes were denuded, the percentage of cleavage was determined and every 10 zygotes were transferred to 100mL drops of culture medium for culture during three days. After 72 hours of culture the percentage of morulae formation was evaluated and these structures were transferred to drops of the same culture medium. At the eighth day of culture blastocyst formation was analyzed. During NBS, from a total of 272 (inactive), 162 (luteal) and 134 (follicular) fertilized oocytes, the percentage of cleaved zygotes, morulae and blastocysts derived from inactive ovaries were 24.63, 16.54 and 8.09 respectively; for those derived from luteal ovaries, the percentage was 21.6, 12.96 and 8.64, and for those from follicular ovaries, they were 24.62, 16.41 and 8.21. Considering BS, from a total of 102 (inactive), 198 (luteal) and 86 (follicular) fertilized oocytes, the relative frequency (%) of cleaved zygotes, morulae and blastocysts derived from inactive ovaries were 64.7, 41.17 and 23.53 respectively; for those derived from luteal ovaries, the percentage was 64.14, 40.41 and 23.73, and for those from follicular ovaries, they were 63.95, 39.54 and 24.41. The results of this experiment demonstrate that no statistically significant difference (P<0.05) was verified in the frequency of cleaved embryos and morulae and blastocyst formation when comparing the three ovarian conditions in the same season. However the breeding season presented better results considering cleavage and morulae and blastocyst formation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The first experiments on sex determination in bees began with Dzierzon, Meves, Nachtsheim, Paulcke, Petrunkewitsch, Manning. Whiting, (1943) found multiple alleles in Bracon xo that are the Rosetta stone of sex determination in Hymenoptera. Whiting also discovered that some species of microhymenoptera do not possess xo sex alleles. Therefore, Hymenoptera apparently presents two types of sex determination superimposed on haplodiploidy. In the panmictic groups hemizygous (xo1, xo2,... xon) and homozygous (xo1xo1, xo2xo2... xonxon) are males while heterozygous (xo1xo2, ... xon-1xon) are females. There is no such series of xon in endogamous Hymenoptera, since the constant elimination of diploid males would be damaging to the population and the mutation of xo to xon would be quickly eliminated. Besides the Whiting hypothesis, four others are discussed. The new hypothesis of genomic imprinting, of Beukeboom, is eliminated since: a) spermatozoa that develop within the egg produce male tissue; b) telitokous parthenogenesis due to the fusion of two haploid cells develop into females; c) last instar larvae treated with juvenile hormone become queens. The Cunha and Kerr hypothesis (female determining genes are totally or partially additive and male determination is totally or partially nonadditive) explains all known cases. The xo is a female determining gene. Sex determination in social bees led to the gradual evolution of two systems of caste determination: one in which queens and workers are similar and males are very different (Apinae), and another in which workers and males are very similar and both very different from the queens (Meliponinae). This second system in stingless bees implies that many of the mutations that improve worker capacities also affect the males that will carry out some activities that in Apis are clearly female ones. Ten of these activities are described.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Juvenile hormone (JH) exerts pleiotropic functions during insect life cycles. The regulation of JH biosynthesis by neuropeptides and biogenic amines, as well as the transport of JH by specific binding proteins is now well understood. In contrast, comprehending its mode of action on target organs is still hampered by the difficulties in isolating specific receptors. In concert with ecdysteroids, JH orchestrates molting and metamorphosis, and its modulatory function in molting processes has gained it the attribute "status quo" hormone. Whereas the metamorphic role of JH appears to have been widely conserved, its role in reproduction has been subject to many modifications. In many species, JH stimulates vitellogenin synthesis and uptake. In mosquitoes, however, this function has been transferred to ecdysteroids, and JH primes the ecdysteroid response of developing follicles. As reproduction includes a variety of specific behaviors, including migration and diapause, JH has come to function as a master regulator in insect reproduction. The peak of pleiotropy was definitely reached in insects exhibiting facultative polymorphisms. In wing-dimorphic crickets, differential activation of JH esterase determines wing length. The evolution of sociality in Isoptera and Hymenoptera has also extensively relied on JH. In primitively social wasps and bumble bees, JH integrates dominance position with reproductive status. In highly social insects, such as the honey bee, JH has lost its gonadotropic role and now regulates division of labor in the worker caste. Its metamorphic role has been extensively explored in the morphological differentiation of queens and workers, and in the generation of worker polymorphism, such as observed in ants.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Bumblebees are a very essential group of pollinating insects, but their populations have declined drastically during the past decades. We need to understand why their numbers are decreasing and what can be done to reverse this trend. Climate change-related phenomena, such as changes in the overwintering temperatures and spring conditions, are among the most prominent threats to bumblebees. Queens have a special role in the lifecycle of bumblebees because they overwinter and start new colonies the next year. Their successful performance: survival, overwintering ability, longevity, immune competence, and nest establishing capability in spring, is highly important for bumblebee populations. However, the effects of climate change on bumblebee queen performance remain unknown. The main objective of this thesis was to assess how temperature affects the performance of bumblebee queens during and after overwintering. The effects of warm temperature predicted by climate change scenarios on queen survival and stress-tolerance were studied by a four-month artificial diapause of bumblebee queens at two temperatures (9°C and 1.8°C). Bumblebee colonies were also reared in a laboratory and factors affecting colony characteristics were examined. In addition, queen performance during spring was studied in a starvation experiment using two temperatures (15°C as normal; 24°C as warmer than average) and queens collected from nature right after their emergence. My research revealed how temperature affects queen performance, and queen size was found to be an important factor determining the direction of some of these effects. We found a 0.4g weight threshold for bumblebee queens to be able to survive overwintering. In addition, during mild winters, larger queens have a higher chance than smaller ones to survive through winter and also to cope with immunological stresses after overwintering. During cold conditions, which are normal in the current climatic situation, this advantage disappears. In the spring starvation experiment, the starved queens survived approximately eight days longer in 15°C than in 24°C, which means that starvation risk rises significantly with increasing spring temperature, in a situation where food is scarce due to for example frost damage or asynchrony between bumblebees and their important food plants. These results could mean that in the future climate, larger queens are better able to survive the winter, initiate their nests and start rearing their offspring. This may be problematic, because I also detected two alternative strategies of colony development that differ between large and small queens; larger queens start to lay eggs earlier at nest initiation, their colonies mature later, they produce more workers, and they have a more strongly male biased sex allocation compared with smaller queens. If larger queens have a greater change of producing offspring after a mild winter, this could lead to a significant decline in the total production of new queens at a population level. Thus, it seems that queen size could act as one mechanism regulating the population level outcomes in different temperatures. The new information presented in my thesis reinforces that basic research, monitoring, and local species conservation of bumblebees both in Finland and globally must be increased to ensure that this highly important pollinator group survives in the face of climate change.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A (mainly votive) missal consisting of seven distinct parts. Put together in several stages, somewhat haphazardly. Parts II and III are probably the oldest parts. The final stage in the composition of the book is probably the addition of part VII. Part II belongs in the same liturgical tradition as C.ö.IV.7 (Oripään Missale I), probably that of Diocese of Linköping. Part III, a votive missal, is an informal copy of a book that would most probably have been used close to a Swedish cathedral (Linköping?). How the present book found its way to Oripää chapel is not known.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Sweat bees exhibit a range of social behaviours, from solitary nesting, in which no workers are produced, to strong eusociality, in which workers exhibit a high degree of altruism, behaviour that is measured by the degree of personal reproductive sacrifice. Field studies were carried out for seven weeks during May-June 2000 in southern Greece in order to investigate intraspecific social variation, and test the hypothesis of a north-south cline of decreasing eusociality in the obligately eusocial sweat bee L. (E.) malachurum. A comparative study, using principal components analysis, was performed to determine if patterns of intraspecific social variation in L. malachurum reflect the patterns of social variation within the subgenus, Evylaeus, as a whole. The results of the field study reveal that, in Greece, two worker broods were produced followed by a third brood consisting of gynes, males and some workers, indicating that there was an overlap in worker and gyne production. There was strong caste distinction between queens and workers. Workers actively foraged and participated in nest construction as most workers (58%, n=303) had a high degree of mandibular wear. Workers did not participate in the oviposition of Brood 3 gynes since only 0.7% (n=278) of workers were mated. Furthermore, queen survival until the end of Brood 3 and a substantial size differential of 10.6% between queens and workers suggested that queen domination over worker behaviour during the early to mid-part of the colony cycle was plausible. Male production in Brood 3 by some workers was likely, since the timing of worker ovarian development corresponded with the timing of male production. These findings suggest that workers of the first two broods were primarily altruistic, but some (28%) Brood 1 (9%) and Brood 2 (19%) workers produced males, indicating that the degree of altruistic behaviour declined during the lifetime of the colony. In comparison with other L. malachurum populations in Europe, the Greek population of L. malachurum had a weaker social level as a result of the higher proportion of workers potentially involved in male production, thus 3 supporting the hypothesis of a southerly cline of decreasing eusociality. Furthermore, intraspecific variation in social level across Europe appears to be due to longer breeding seasons in more southerly locations that would promote the production of larger colonies and provide opportunities for workers to evade queen control. The comparative study using principal components analysis on 20 solitary (of the subgenera Evylaeus and Lasioglossum), eusocial and socially polymorphic Evylaeus species and populations reveals that six traits are closely associated with stronger eusociality in Evylaeus. These traits are: (1) a reduction in the proportion of males in the early brood(s); (2) a reduction in the proportion of females that mate; (3) an increase in the mean number of first brood workers; (4) a reduction in the proportion of females with developed ovaries; (5) an increase in size dimorphism between castes, and (6) nest guarding. These are traits that most significantly define principal component one and therefore distinguish social type as indicated by a clear separation of the eusocial and the solitary populations, with a socially polymorphic species falling in between. Furthermore, most of these traits are under foundress control and may suggest that the evolutionary loss or gain of eusociality is based on selection pressures on a founding female. Colony size and female ovarian development are common factors distinguishing social variation in L. malachurum and within the subgenus as a whole. The principal components analysis excluding the solitary species and the socially aberrant L. marginatum populations show the L. malachurum populations separated based on an increasing proportion of workers with developed ovaries as populations are found more south, lending further support to the hypothesis of a north-south cline of decreasing eusociality.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In 1852 Robert Dolmage (ca. 1821-1889) a merchant of Palermo, Halton County, Ontario married Frances Palmer of Toronto. Together they had four daughters: Carrie, Fanny, Laura and Florence. The family resided in Halton County until they moved to Grimsby, Ont. after 1871 and before 1881. Robert Dolmage died in 1889 and his wife, Frances died in 1904. After Robert’s death the family continued to reside in the family home on Main Street in Grimsby, Ont. and the business interests were looked after by Claude A. Boden. Mr. Boden became one of the prime beneficiaries of Florence Palmer Dolmage’s estate after her death in 1945. Florence Dolmage was buried in Queen’s Lawn Cemetery on July 7, 1945. As she was the last remaining member of this family her estate was dispersed to extended family members as well as charitable organizations. At this time, no information is known about the connection between the Dolmage and Sillett families.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Welland Power and Supply Canal Company Limited, established in 1893 and incorporated in 1894 with a capital stock of $500,000. The aim of the company was to harness the natural water supply of the Niagara and Welland Rivers. In 1898 the Canadian Electrical News published a report by Henry Symons, QC outlining the main project of the company. This project involves the construction of a canal from the Welland River to the brow of the mountain at Thorold, a distance of 8 miles; the construction at Thorold of a power house, and from Thorold to Lake Ontario, a raceway by which to carry water into the lake. The estimate for the machinery to generate 100,000 horse power is £125,000; for transmission line to Toronto at a voltage of 10,000….The total estimate therefore amounts to £2,452,162, or roughly speaking, $12,000,000. Source: Canadian Electrical News, August 1898, p. 172. In 1899 the company officers petitioned the federal government desiring a name change to the Niagara-Welland Power Company Limited. Officers of the company were Harry Symons, President; Charles A. Hesson, Vice-President; and M.R. O’Loughlin, James B. Sheehan, James S. Haydon, Frederick K. Foster, directors; John S. Campbell, secretary-treasurer. The company’s head offices were located in St. Catharines, with a New York (City) office on Broad Street. In 1905 and 1909 the company petitioned the federal government for additional time to construct its works, which was granted. The company had until May 16, 1915 to complete construction. John S. Campbell (1860-1950) was a graduate of the University of Toronto and Osgoode Hall. During his university years John began his military career first in "K" Company, Queens Own rifles and then later as Commanding Officer of the 19th Lincoln Regiment, from 1906 to 1910. Upon his return to St. Catharines John Campbell served as secretary in the St. Catharines Garrison Club, a social club for military men begun in 1899. After being called to the Bar, he became a partner in the firm of Campbell and McCarron and was appointed to the bench in 1916, serving until retirement in 1934. Judge Campbell served as an alderman for several terms and was the mayor of St. Catharines in 1908 and 1909. He also served as the first chairman of the St. Catharines Public Utilities in 1914. John S. Campbell was married to Elizabeth Oille, daughter of Jerome B. and Charlotte (St. John) Oille. The family home "Cruachan" was located at 32 Church St.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

‘The Father of Canadian Transportation’ is a term commonly associated with William Hamilton Merritt. Although he is most known for being one of the driving forces behind the building of the first Welland Canal, he was many things throughout his life; a soldier, merchant, promoter, entrepreneur and politician to name a few. Born on July 3, 1793 at Bedford, Westchester County, N.Y. to Thomas Merritt and Mary Hamilton, Merritt’s family relocated to Canada shortly after in 1796. The move came after Merritt’s father petitioned John Graves Simcoe for land in Upper Canada after serving under him in the Queen’s Rangers during the American Revolution. The family quickly settled into their life at Twelve Mile Creek in St. Catharines. Merritt’s father became sheriff of Lincoln County in 1803 while Merritt began his education in mathematics and surveying. After some brief travel and further education Merritt returned to Lincoln County, in 1809 to help farm his father’s land and open a general store. While a farmer and merchant, Merritt turned his attention to military endeavours. A short time after being commissioned as a Lieutenant in the Lincoln militia, the War of 1812 broke out. Fulfilling his duty, Merritt fought in the Battle of Queenston Heights in October of 1812, and numerous small battles until the Battle of Lundy’s Lane in July 1814. It was here that Merritt was captured and held in Cheshire, Massachusetts until the war ended. Arriving back in the St. Catharines area upon his release, Merritt returned to being a merchant, as well as becoming a surveyor and mill owner. Some historians hypothesize that the need to draw water to his mill was how the idea of the Welland Canals was born. Beginning with a plan to connect the Welland River with the Twelve mile creek quickly developed into a connection between the Lakes Erie and Ontario. Its main purpose was to improve the St. Lawrence transportation system and provide a convenient way to transport goods without having to go through the Niagara Falls portage. The plan was set in motion in 1818, but most living in Queenston and Niagara were not happy with it as it would drive business away from them. Along with the opposition came financial and political restraints. Despite these factors Merritt pushed on and the Welland Canal Company was chartered by the Upper Canadian Assembly on January 19, 1824. The first sod was turned on November 30, 1824 almost a year after the initial chartering. Many difficulties arose during the building of the canal including financial, physical, and geographic restrictions. Despite the difficulties two schooners passed through the canal on November 30, 1829. Throughout the next four years continual work was done on the canal as it expended and was modified to better accommodate large ships. After his canal was underway Merritt took a more active role in the political arena, where he served in various positions throughout Upper Canada. In 1851, Merritt withdrew from the Executive Council for numerous reasons, one of which being that pubic interest had diverted from the canals to railways. Merritt tried his hand at other public works outside transportation and trade. He looked into building a lunatic asylum, worked on behalf of War of 1812 veterans, aided in building Brock’s monument, established schools, aided refugee slaves from the U.S. and tried to establish a National Archives among many other feats. He was described by some as having “policy too liberal – conceptions too vast – views too comprehensive to be comprehensible by all”, but he still made a great difference in the society in which he lived. After his great contributions, Merritt died aboard a ship in the Cornwall canal on July 5, 1862. Dictionary of Canadian Biography Online http://www.biographi.ca/EN/ShowBio.asp?BioId=38719 retrieved October 2006 Today numerous groups carry on the legacy of Merritt and the canals both in the past and present. One such group is the Welland Canals Foundation. They describe themselves as: “. . . a volunteer organization which strives to promote the importance of the present and past Welland Canals, and to preserve their history and heritage. The Foundation began in 1980 and carries on events like William Hamilton Merritt Day. The group has strongly supported the Welland Canals Parkway initiative and numerous other activities”. The Welland Canals Foundation does not work alone. They have help from other local groups such as the St. Catharines Historical Society. The Society’s main objective is to increase knowledge and appreciation of the historical aspects of St. Catharines and vicinity, such as the Welland Canals. http://www.niagara.com/~dmdorey/hssc/dec2000.html - retrieved Oct. 2006 http://www.niagara.com/~dmdorey/hssc/feb2000.html - retrieved Oct. 2006

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A photograph of Samuel DeVeaux Woodruff (1894-1918) in uniform in a garden with a dog. In 1916, he was a Lieutenant in the 176th unit of the Queen’s Battalion. Samuel was engaged to Gladyse Wanita Palling, but they never married. He was killed in action on the July 13, 1918 as a member of the 116th Battalion of the Canadian Infantry (Central Ontario Regiment).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Province of Upper Canada Grant (vellum) to Thomas Fraser of the Township of Edwardsburgh granted 1 acre in Lot no.9 in the County of Stormont. Signed by William Jarvis, Sir Isaac Brock, Prideaux Selby and John Macdonell. There are some holes in the document and there are small pieces missing on the right hand side. William Jarvis was the Provincial Secretary of the Lt. Governor of Upper Canada; Sir Isaac Brock. Jarvis was an officer in the Queen’s Rangers. He also served as Provincial Secretary of Upper Canada. A partial crown seal is attached, Mar. 26, 1812.