No presente trabalho caracterizou-se o padrão de utilização de conchas pelo ermitão Paguristes tortugae, habitante do infralitoral da Ilha Anchieta (Ubatuba), analisando-se comparativamente o padrão de seleção e de ocupação de conchas no ambiente natural e em laboratório. Para o estudo de ocupação de conchas no ambiente, os indivíduos foram coletados mensalmente (janeiro a dezembro/1998) na região infralitorânea de quatro áreas da Ilha, por mergulho autônomo. Os ermitões foram medidos quanto ao comprimento e largura do escudo cefalotorácico, altura e comprimento do própodo quelar, contados, determinado seu sexo e pesados. Para os experimentos de seleção de conchas, os animais foram mantidos vivos em aquário de vidro. Nestes experimentos laboratoriais, os animais foram retirados de suas conchas e colocados com um número suficiente de conchas com tamanhos apropriados. Após 72h os animais e as conchas escolhidas foram analisados quanto ao peso dos ermitões e das conchas e as respectivas medidas. A escolha quanto ao tipo de concha foi analisada de acordo com a porcentagem de ocupação de uma espécie em relação à outra. Para a escolha quanto ao tamanho da concha, avaliou-se as análises de regressão entre as dimensões dos ermitões e das conchas. Um total de 2429 exemplares de P. tortugae foram analisados (1092 machos, 495 fêmeas não-ovígeras e 842 fêmeas ovígeras), ocupando 21 espécies de conchas de gastrópodos. Este perfil, indicativo de ampla diversidade no padrão de ocupação, apresentou Pisania auritula (35.49%), Cerithium atratum (27.83%) e Morula nodulosa (12.70%) como as mais ocupadas. Os machos (38.46%) e as fêmeas ovígeras (38.00%) ocuparam, em maior porcentagem, as conchas de P. auritula, enquanto que as fêmeas não-ovígeras (39.40%) ocuparam C. atratum. Houve dimorfismo sexual quanto ao tamanho em favor dos machos e, a razão sexual foi de 1:1.2, em favor das fêmeas. Verificou-se que as conchas mais ocupadas foram as menos adequadas. Leucozonia nassa foi a mais adequada tanto no ambiente quanto no laboratório, corroborando a hipótese de que a ocupação das conchas está associada ao ambiente em que vivem e à sua disponibilidade. A maior correlação ocorreu entre as dimensões dos ermitões e o peso da concha, sendo esta a relação que melhor caracterizou a escolha e a ocupação das conchas por P. tortugae. Quanto ao sexo, as fêmeas ovígeras apresentaram as melhores correlações, estando melhor adequadas ao peso e ao volume interno da concha, favorecendo a fecundidade e o processo reprodutivo anual. Tal condição foi corroborada com os experimentos de laboratório, onde constatou-se que as fêmeas ovígeras apresentaram preferência por conchas com maior volume interno (L. nassa e C. atratum). Em laboratório, dentre as seis espécies de conchas com maior ocorrência de ocupação no ambiente, o padrão de preferência foi L. nassa > P. auritula > S. haemastoma > T. viridula para os indivíduos maiores e C. atratum > M. nodulosa para os indivíduos menores. Estes resultados, comparados aos da natureza, demonstraram que P. tortugae apresentou um padrão de preferência pelas conchas mais disponíveis na natureza, mesmo não sendo as mais adequadas quanto às dimensões. Neste sentido podemos inferir que o padrão de utilização de conchas de P. tortugae pode estar fortemente associado à disponibilidade de conchas, ao tamanho e à condição reprodutiva dos indivíduos. / This study characterized the pattern of shell utilization by the hermit crab Paguristes tortugae, inhabiting infralittoral areas of Anchieta Island (Ubatuba), analyzing comparatively the pattern of the shell occupation in the field and in the laboratory. For the shell occupation study in the field, the individuals were collected monthly (January to December/1998), by scuba methods in four infralittoral areas of the Island. The hermit crabs were measured on the basis of shield width and length, propodus height and length, sexed and weighed. In the shells selection experiments, the animals were maintained alive in the laboratory. All experiments were conducted in a glass aquarium where the hermit crabs were placed naked with a large number of shells of appropriate sizes. After 72h the hermit crabs and chosen shells were analyzed by preference and measured. The shell type preference was estimated by the percentage of occupation of the chosen species. The preferred shell type and size were determined by regression analysis. A total of 2429 individuals of P. tortugae were analyzed (1092 males, 495 non-ovigerous females and 842 ovigerous females), occupying 21 species of gastropod shells characterizing a considerable diversity in the shell occupation pattern. The most occupied shells were Pisania auritula (35.49%), Cerithium atratum (27.83%) and Morula nodulosa (12.70%). The males (38.46%) and the ovigerous females (38.00%) occupied in higher percentage P. auritula shells, while the non-ovigerous females (39.40%) occupied C. atratum. It was verified sexual size dimorphism, being the males larger than females. The sex ratio was 1:1.2 in favor of females. It was verified that the most occupied shells least adequate and that L. nassa was the most adequate in the field and in the laboratory, corroborating the hypothesis that the shell utilization is associated to the habitat and to the availability in the field. The highest correlation coefficients were obtained for the relations between the crab dimensions and shell dry weight. In relation to sex, the ovigerous females showed the best correlation coefficients being more adequate to the shell weight and internal volume, that may favor the fecundity and the annual reproductive process. This condition was corroborated by the laboratory experiments when the ovigerous females preferred shells with higher internal volume (L. nassa e C. atratum). In laboratory, among the six most occupied shell species in the field, the preference pattern was L. nassa > P. auritula > S. haemastoma > T. viridula to larger individuals and C. atratum > M. nodulosa to the small ones. These results, compared to the field study, showed that P. tortugae exhibited a pattern of preference for the most available shells in the field, even if they’re not the most adequate to the crab dimensions. In this sense we may infer that the shell utilization pattern of P. tortugae may be associated to the shell availability and to the size and reproductive conditions of the individuals.

<p>The dissertation work discussed here focuses on the behavioral and physiological aspects of visual sexual signaling in the blue crab, <italic>Callinectes sapidus</italic>. The blue crab has a pair of apposition compound eyes that are relatively acute (1.5 &deg; resolution) for an arthropod. The eyes have two photopigments sensitive to blue (&lambda;_max = 440 nm) and green (&lambda; _max=500 nm) light, allowing for simple color vision. Visual cues and signals are used during antagonistic and sexual communication and primarily involve claw-waving motions. A primary feature of the blue crab morphology is its sexually dimorphic claw coloration; males have blue and white claws and females have red claws. However, despite the potential for interesting color signaling, visual cues have typically been considered non-important, particularly in sexual communication where chemical cues have dominated blue crab signaling studies. </p><p>In a series of experiments designed to simultaneously test the role of visual cues in mating behavior and blue crab color vision, I tested males' responses to photographs of females with differently colored claws. I found that photographs of females elicited male courting behaviors. I also found that males preferred females with red claws over those with white or isoluminant (i.e. matched brightness) gray claws. The discrimination of red from isoluminant grey showed the use of color vision in male mate choice. </p><p>In natural populations, the claws of sexually mature females vary from light orange to deep red. To determine males' abilities discriminate between similar colors, I tested male color preferences for red against several shades of orange varying in brightness. Overall, males showed an innate preference for red-clawed females over those with variations of orange claws. However, in tests between red and orange shades similar in both brightness and hue, male blue crabs did not show a distinct preference, suggesting that males are either not able or not motivated to discriminate between these shades. Further, my results suggest that male blue crabs may use a mixture of chromatic and achromatic cues to discriminate between long-wavelength colors.</p><p>After confirming the use of color in mate choice, I focused on the role of claw color in intraspecific communication. To quantify claw coloration, I measured spectral reflectance of claws of a blue crab population in North Carolina. In both sexes, the color of the claw varied with reproductive maturity and may act as a cue of reproductive readiness. Additionally, there was individual variation in claw color which could indicate individual quality. I have modeled the appearance of claw coloration to the blue crab eye and found that these color differences are visible to the blue crab eye and potentially signal gender, reproductive readiness, and/or individual quality. </p><p>After investigating male mate choice, I began investigating visual aspects of female mating behavior. In the blue crab, like many crustaceans, courtship occurs during the female molting cycle and copulation takes place after the female has shed her exoskeleton. In crustaceans and other arthropods with compound eyes, the corneal lens of each facet is part of the exoskeleton and thus shed during molting. I used optomotor assays to evaluate the impact of molting on visual acuity (as measured by the minimum resolvable angle <italic> &alpha _min</italic>) in the female blue crab. I found that visual acuity decreases substantially in the days prior to molting and is gradually recovered after molting. Prior to molting,<italic> &alpha_min </italic>was 1.8 &deg;, a value approximating the best possible acuity in this species. In the 24 hours before molting, <italic> &alpha _min</italic>increased to a median of 15.0 &deg; (N=12), an eight-fold drop in visual acuity. Six days after molting, <italic> &alpha _min</italic>returned to the pre-molting value. Micrographs of <italic>C. sapidus </italic> eyes showed that a gap between the corneal lens and the crystalline cone appeared approximately five days prior to shedding and increased in width the process progressed. This separation was likely responsible for the loss of visual acuity observed in behavioral tests. Since mating is limited to the female's pubertal molt, a reduction in acuity during this time may have an effect on the sensory cues used in female mate choice. These results may be broadly applicable to all arthropods that molt and have particular importance for crustaceans that molt multiple times in their lifetime or have mating cycles paired with molting.</p> / Dissertation

¡@The shell utilization of two sympatric hermit carb species was studied in shallow waters of Kaohsiung and Pingtung, southern Taiwan. Principal components, canonical variates and univariate analysis was used to compare three major variables of shell resource: species, size, and shape between species and sites. The regression between crab and shell and shell adequacy index (SAI) revealed that two species shared the same resource which had shell size limitation in the field had different pattern. Shells used by Diogenes rectimanus were larger than those uesd by D. nitidimanus of same size. But the utilization pattern was the same under a shell sufficient condition in the laboratory, suggesting that there was no resource partitioning or competition between these two species. The size of shell composed a continuous morphological overlap at four different sites and shown a good consistency with crab size. This revealed the utilization of crabs in different size selected different shells and suggested a status of sufficient resource utilization. Although the shell resource were highly similar, but different composition of shell species and other factors could caused variances in shell size and shape between four sites, and caused crab size divergence among different populations.

Many species use color during courtship displays, with the more colorful individuals often selected as potential mates. Female blue crabs, Callinectes sapidus, display prominent red markings on their chelipeds, which is absent in males. I tested the hypothesis that females use this sexual dimorphism as an effective signal to potential mates. Body size was positively correlated with size of the colorful pattern on the crusher dactyl. Digital imaging techniques were used to examine and quantify a pattern of coloration in the female blue crab. Morphometric measurements were made using digital images of the carapace and chelae of crabs collected along the Gulf of Mexico coast in Galveston, Texas. Color complexity was examined on digital images of the chelae using Adobe? Photoshop? and Image J. Specific wavelengths were selected and their presence within the attribute quantified and evaluated. To determine whether male blue crabs prefer more colorful females, males were given a choice between females of different female coloration. Males displayed more often and directed more courtship displays towards the more colorful females. I hypothesize that male blue crabs use cheliped coloration as a visual cue for mate selection.

This study is the first attempt to investigate heavy metal concentrations in the soldier crab with a view to it being a potential candidate for the monitoring of copper(Cu), zinc(Zn), nickel(Ni), lead(Pb) and cadmium(Cd) levels on the western coast of Taiwan. The objectives of this investigation included the following: (1) to assess the pollution status at different sites by determining the metal concentrations of ambient water and Pacific oysters; (2) to monitor the concentrations of heavy metals, including Cu, Zn, Ni, Pb and Cd, in the soldier crab; (3) to assess the effect of sex, wet weight and reproductive season at different sites¡F(4) to investigate the distribution of metal concentration among carapace, gonads, midgut gland, muscle; and (5). to assess the pollution status at different sites and years by monitoring the concentration of heavy metals, including Cu, Zn, Pb and Cd in male soldier crabs The Pacific oyster and stream results proved that site B is contaminated by Cu, Zn and Pb from streams B-1 and B-2. The highest Cu, Zn, Ni and Pb concentrations in soldier crabs appeared at site B, and significant differences in the accumulated concentrations of Cu, Pb, Zn and Ni in soldier crabs were found between the sites tested. The highest bioconcentration factors of Cu, Zn, Ni and Pb in soldier crabs appeared at site B, indicating that the soldier crab can accumulate Cu, Zn and Pb to the same degree as the Pacific oyster. In fact, soldier crabs can accumulate more Ni than Pacific oysters, better reflecting the conditions of the ambient environment. These phenomena, as well as the fact that the soldier crab is able to accumulate relatively high levels of Cu, Zn, Pb and Ni, suggest that this crab is a potential biomonitor of Pb and Ni pollution in aquatic ecosystems. Only in the case at site A of Pb sex related difference could be detected. In general mean Pb level in male soldier crabs were higher than in female. There are no significant sex related differences of Cu, Zn, Cd and Ni in soldier crab among three sites. The lead mean concentration in reproduction season and pre- reproduction season were higher than non-reproduction seasons. The highest concentrations of lead were found in carapace and the gonad in reproduction season. The results presented that the metal concentration in soldier crabs vary significantly not only because of season change in polluted sites, but also it may be influenced by the sex-related and size-related difference of organisms. After eliminating size effect, sex effect by analyzing 0.7 g~ 1.0 g and male soldier crabs to monitor the pollution status, the Cu and Zn concentrations in soldier crabs along the Changhua coastline(site A and site B) is stable¡F The higher concentrations of Pb and Cd in soldier crabs existed in 2002 and 2003. We suggested that the polluted sources of Pb and Cd along the Changhua coastline in 2002 is abundant, and of Pb contents from 2003 to 2006 and Cd content from 2003 to 2007 are decreasing. Therefore, it is essential to take size effect, sex, season, and polluted status into account in comparative biomonitoring studies using soldier crabs as metals biomonitor. The baseline concentration of soldier crabs were 21.4 £gg g-1 wet wt. Cu, 20.1 £gg g-1 wet wt. Zn, 0.13 £gg g-1 wet wt. Pb, 0.12 £gg g-1 wet wt. and 0.91 £gg g-1 wet wt..

Thesis (M.S.)--University of North Carolina at Wilmington, 2003.

We aimed to identify the volatile compounds in inflorescences of Rudbeckia hirta that may be responsible for the olfactory attraction of the crab spider Misumenoides formosipes to this plant. Our approach was to use ultrasonic extraction, separate the extract into fractions using flash chromatography with different solvent systems, and test the attraction of the male spiders to the pooled fractions using a y-tube olfactometer. Ultrasonic extraction is carried out using a mixture of 1:2 hexane/diethyl ether with 10 g of inflorescences for 30 minutes. Bioassay results indicated that male spiders chose the inflorescences, bulk ultrasonic extract, and the pooled 100% dichloromethane fractions over controls. Nuclear magnetic resonance experiments and infrared spectroscopy experiments were carried out on the 100% dichloromethane fractions and these experiments indicated that a long chain hydrocarbon is the main component in the 100% dichloromethane fractions / Chromatographic method and bioassay development method -- M. formosipes olfactory response to R. hirta -- Separation and identification of the possible attractants in the 100% dichloromethane fractions. / Department of Chemistry

Graduation date: 1961

H.rotundifrons A. Milne Edwards, 1867, the big-handed crab, belongs to the Belliidae and is the only crab representative of this family in New Zealand. It lives in the intertidal zone. The megalopae undergo 13-16 moults to become fully mature at a size of 11-13mm CWo These mature crabs live up to a maximum of 19 years and attain a size of 23-25mm CW (24-26 instars). The laboratory growth curve of H.rotundifrons is asymptotic and there is no terminal ecdysis. Growth is similar between the sexes up to maturity but decreases more in males after puberty thus exhibiting an "anomalous" pattern. Average weight gain after ecdysis was found to be same for both sexes and independent of size (approx. 18%). Environmental and physical factors which normally affect growth have no profound effect on H.rotundifrons. However, moult frequency was found to be increased by removal of eyestalks or when crabs were maintained in constant darkness. Starvation and limb removal considerably reduced the moult increment. Alpha ecdysone concentration increased to a peak 40 days before ecdys is and returned to base 1eve1s at moulting. Moulting is seasonal having a high peak in mid-summer and a smaller peak in April-May. A field study of dispersal showed that short-range movements (5.06m), within the intertidal zone, are common for H.rotundifrons (n=212). Many crabs left their refuge between low tides and their movements were independent of one another. Neither home range nor long dispersal movement (>21m) have been observed in H.rotundifrons. Diet of H.rotundifrons comprised algae (60.7%), crustaceans (19.6%), sand & unidentified materials (11.7%), sponges & worms (5.7%), and molluscs (2.3%). Although brown algae were always the single dominant food item, diet composition varied seasonally. The majority of the population at Kaikoura (602(M):858(F)) consisted of pre-pubertal males and females and fewer post-pubertal males were found than post-pubertal females, a reflection of slower male growth and suggesting higher male mortality.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.