The geographic distributionof Parechinus angulosus according to present II records extend from Umhlali (Zululand) to Luderitz Bay (Day, 1974). The urchins are therefore adapted to a wide range of temperatures. Maximum fluctuations probably occur along the stretches of coastline affected by upwelling, the South-West, and west coasts, with differentials of twelve degrees Centigrade and more. Furthermore, these fluctuations may take place within a matter of a few hours or even less, i.e., almost capriciously Like temperature changes encountered on land but, unlike, the latter, by virtue of movement of different water masses, rather than cooling rate. The importance of temperature as a regulator of reproductive cycles in marine organisms, specifica'ly invertebrates, is discussed in Giese and Pearse's (1974) detailed review on the subject. A local study by Newman (1969) considers the effect of temperature on the spawning behaviour of abalone (Haliotis midae). This study was commenced in the light of this information and subjective preliminary observations underwater, which revealed striking density and relative size differences between urchins on the Atlantic side of the Peninsula and in the warmer False Bay. A detailed in situ record of sea temperatures at two study sites, Robben Island and Millers Point was obtained by installing temperature measuring devices. This monitoring covered a period of one year, while coupled with monthly collections of urchins in the mature size range. The variations of male and female gonad indices were found to be essentially in agreement, though lagging behind sea temperature changes. The spawning periods of urchins at both study sites was similar, occurring in spring and autumn, despite the significantly different water temperature averages. A clear pattern was observed at Millers Point, while being poorly defined at Robben Island. This is in agreement with the findings of Newman (1967, 1969), whose observations included data from St. Helena Bay to beyond Port Elizabeth. Newman found higher spawning intensities at localities having a clear seasonal pattern of sea temperature variations, compared to those of low seasonality, in other words, better synchrony of gamete release. A possible mechanism was mentioned by Giese & Pearse (1974), suggesting that the ripest individuals may be induced to spawn by a sharp temperature change, thereby stimulating other less mature individuals to follow suit. The degree of perturbation necessary to initiate such a sequence can vary widely. Many species are known to have breeding seasons in areas where temperature fluctuations are slight, such as parts of the polar, tropical, and abyssal ocean. My observations indicate that a confused temperature regime, involving rapid changes, such as occur during periodic upwelling cycles, results in repeated, incomplete spawn-outs. Consequently, gonad indices are always lower at Robben Island tha·n at Millers Point. Urchins at both localities show a low reproductive status during winter. Stained histological thin sections were prepared of gonad portions of selected urchins of both sexes covering all _maturity. (Gonad index) stages and compared with lipid values obtained for the same respective animals. It was found that during maturation, there is a gradual build-up of gametes passing through the well-known developmental stages, rather than a snap conversion of accumulated storage material (I only tested for lipid for practical reasons) into sperms or eggs. Even relatively regressed {low gonad index) urchins could be induced to release fertilizable spawn, by injection of potassium chloride solution. Lipid values form a surprisingly small portion of the total dry mass of the urchin, when it is realised that it is the gonads which function as the major storage organ in addition to the . intestine (Boolotian, 1966). Except for a few high, possibly spurious, values, male 1 ipid levels were on the whole lower than those found for females. It would have been interesting to have values for glycogen as well for comparison, particularly since calorific values obtained for representative male and female Parechinus by micro-bomb calorimetry were found to be in very close agreement, in fact practically identical. The significant mean size differences between urchins of the 2 study sites could be shown to be very 1 ikely due to the availability of food. This was shown by a comparison of gut states of urchins collected during the period of study. Although it is true that suspended food material is more plentiful in an upwelling locality, like Robben Island and unlike Millers Point, this situation is only important to the planktonic and recently settled juvenile stages of Parechinus. Once the animal has reached a test diameter of 10 mm (Greenwood, 1980), macroscopic and attached food sources A~~ required. In this respect Robben Island is clearly limiting. Hence urchins of a smaller mean size relative to Millers Point enter the reproductive life eyelet, since only that fractfon over and above the animal 1 s metabolic requirements is available for growth and reproduction. The significantly lower (one quarter) gamete output of urchins from Robben Island is evidence of this fact. Recruitment of Parechinus into the benthonic stage appears to be strongly dependent on substrate, in that the eroded, slaty structure of the reefs at Robben Island afford many suitable microhabitats to juveniles at this particularly vulnerable stage, while the rounded granite boulder terrain at Millers Point does not offer a comparable number and choice of such sites. Tegner and Dayton (1977) showed that substrate type may play an important role in the recruitmaitof a Californian species, Strongylocentrotus purpura~us, which like Parechinus is flexible in its recruitment behaviour, which means that the urchins select suitable sites from a range of choices, while - S. franciscanus juveniles shelter under the spine canopy of adults. The size class study sites must be seen in this light. In effect then we have a situation, where substrate type and availability jointly select against the smaller size classes at Millers Point. The strongly contagious distribution of Pa:l'echinus is very likely a response to the proximity of food. Since debris tends to accumulate on horizontal surfaces, urchins can be expected to be more numerous there than on inclined substrate. This was found to be true in a study by Vel imi rov et al. (1977), who made the dividing line between horizontal and vertical at 45° inclination. In addition, minor adjustments according to sea strate take place. It was found that under turbulent conditions urchins shelter on rockfaces away from I the sea and under overhangs to avoid strong swell action and contact with loose material such as torn off kelp plants. Predation was not studied and therefore only tentative impressions gained per chance in the field are at hand. Robbeneiland lying in a security area is largely undisturbed and harbours many rock lobsters (Jasus lalandii), which prey on Pa:l'echinus in addition to their main food, the ribbed mussel (Aulacomya ater). Indeed, lobsters were seen to feed on urchins on a number of occasions, apparentl_y selecting the smaller individuals. rare for many years through overexploitation. At Millers Point Jasus has been There appears to be no significant departure from the 1 :1 sex·ratio at either site according to Chi-square analysis. However, a more powerful analysis of variance and co-variance indicated a higher number of males at Robbeneiland. The discrepancy may be due to the fact that while Chi-square analysis was done on small (30 batches of urchins collected on a monthly basis and comprising mainly sexually matureindividuals at various stages of gonadal development, the Anova involved material obtained during seasonal transects including a wide range of size classes, particularly at Robbeneiland . Indeterminate urchins were excluded from the analysis, but nevertheless, misidentifications favouring males did occur. It would therefore appear that there is little reason to assume that the sex ratio of Parechinus is significantly unsymmetrical.

No description available.

Lotus corniculatus L. (Legtuninosae), is a perennial herb common throughout Britain. Its main pollinators are bumblebees (Bombus spp., Apidae: Hymenoptera). This is a study of the ecological factors which are important to flowering and fruiting in the species, and some of their evolutionary implications. The work was carried out at Wytham Estate, Oxfordshire, U.K., mainly in an ex-arable field (Upper Seeds) and a more established grassland (Lower Seeds Reserve). The literature on self-incompatibility in L. corniculatus is reviewed; there are conflicting reports, but wild material is fundamentally self-incompatible. Plants in Upper Seeds are larger than in Lower Seeds Reserve. Comparative data on soil nutrients in the two sites suggests that the cause is the persistence of phosphorus from inorganic fertiliser. There is a positive, linear relationship between plant size, flower production and fruit production. The species regulates investment in flowers mainly at the level of the whole inflorescence, rather than altering number of flowers per inflorescence. Within individuals, there are no consistent trade-offs between number of fruit per infructescence, numbers of seeds per fruit and seed weight. Weather patterns only partially explain the flowering phenology of L. corniculatus. Timing of first flowering and peak flowering are correlated but are variable between individuals, and between years for the same individuals. They are not correlated with flowering synchrony. An individual's flowering pattern does not consistently affect fruit-set; the overriding determinant of fruit production is plant size. Selection is therefore unlikely to be acting on flowering time in this species. The production of large numbers of self-incompatible flowers does not seem to reduce fruit-set; pollinators do not visit enough flowers per foraging trip (perhaps because nectar production is low) for geitonogamy to become a problem. Seed predation by larvae of a chalcid wasp, a weevil and a moth differs between individual plants, but not consistently so between years. Seed predation is not consistently correlated with plant size, mean flowers per inflorescence, number of seeds per fruit or seed size. There is no evidence for selection acting on these traits through seed predation. Partially predated seeds are often viable, which may have implications for seedling demography. Seed predation and flowering phenology are not defmitively linked, strengthening the argument that flowering time is not adaptive in this species.

The reproductive ecology of nine aroid species in the rain forests around Kumasi in Ghana was studied. These species included two seasonal geophytes; Amorphophallus johnsonii and Anchomanes difformis, two herbaceous species; Culcasia saxatilis and Culcasia striolata, Four hemi-epiphytic species with terrestrial phases; Cercestis afzelii, Cercestis stigmaticus, Culcasia angolensis and Culcasia parviflora, and one hemi-epiphytic species without a terrestrial phase when mature; Rhaphidophora africana. These aroids are pollinated by beetles and flies. Anchomanes difformis and Culcasia angolensis exhibit floral heating. Trap mechanisms are present in the inflorescences of Amorphophallus johnsonii, both Cercestis species, in Culcasia parviflora and in C.saxatilis. Pollen is psilate or verrucate to bacculate in most species, but echinate in Culcasia angolensis. Ripe infructescences in most species consist of clusters of large orange to red coloured berries, but Rhaphidophora africana develops gravid spadices, with the outer tapetum peeling away to reveal naked seeds in a pulp. The seeds in most of these aroids germinate quickly and produce high percentage germination, but Amorphophallus johnsonii exhibits bimodal germination, with some seeds germinating immediately and others delaying germination until 8 months later. Evidence of berry flesh inhibition was found in Cercestis afzelii. Two main patterns of climbing are displayed by the hemi-epiphytic aroid species, with continuous growth in Culcasia angolensis and Culcasia parviflora and periodic climbing shown by Cercestis afzelii, Cercestis stigmaticus and Rhaphidophora africana. Growth towards dark areas or 'skototropism' is evident in Culcasia angolensis, Culcasia parviflora and to some extent in Cercestis stigmaticus.

<I>Rhinolophus hipposideros </I>has declined across its range. This study aimed to investigate aspects of its roosting, reproductive and foraging ecology which may have caused this decline. <I>R. hipposideros </I>is confined to south west Britain. It selects roosts in areas of undulating countryside with hedgerows and tree lines. Roosts were located predominantly in the roof voids of 19^th century buildings with stone walls and slate roofs, close to woodland and connected to it by hedgerows or tree lines. <I>R. hipposideros </I>has a long gestation period (78 days) and proportionately larger neonate (34% mothers mass) compared to other bat species. Post-natal growth was one of the fastest recorded for a bat species. The number of pups produced by colonies averaged 38% of pre-parturition counts of adults. Ambient temperature in May was shown to influence the reproductive phenology of this species. Patterns of roost occupancy and activity were investigated in a maternity, satellite, night and hibernation roost. Numbers of adults in the maternity roost peaked just before parturition. The timing of emergence and return from the maternity roost each night was correlated with ambient light levels. The duration of foraging each night was correlated with date and was reduced on nights with heavy rainfall. The importance of night roosts to heavily pregnant bats was demonstrated. During the winter most feeding took place before the end of December but successful foraging occurred throughout the winter. <I>R. hipposideros </I>foraged in woodlands, hedgerows and tree lines within 2-3 km of the maternity roost. It hunted close to vegetative clutter catching prey by hawking, gleaning and in late pregnancy by fly-catching, using hedgerows and tree lines as commuting routes between foraging areas and roosts. The implications of this study for the conservation of this species are discussed and management recommendations made.

Tarebia granifera is an ovoviviparous and parthenogenetic freshwater snail indigenous to South East Asia. T. granifera was introduced into many areas of the world as a result of human activity and caused detrimental effects on native freshwater snails. T. granifera also served as the first intermediate hosts of many digenetic trematodes. Specimens of T. granifera were collected seasonally in Jinlun River, S.E. Taiwan, from April, 2003 to January, 2004. The embryo composition in the brood pouches was compared among seasons. We found the species was fertile and the embryo composition was similar throughout the year. The maximum embryo number occurred in October, 2003, and the minimum occurred in January, 2004. T. granifera was reared to compare juvenile releasing rates in summer and winter. More juveniles were released per mother-snail in summer than in winter. And low water temperature seemed to inhibit juvenile release in cold days. The survival rates of brooded juveniles outside brood pouches were tested. Except the smallest size group (shell height=0.25~0.50mm), all others (0.5~1.25mm) had high survival rates approaching 100%. About 15% of the snails were infested by unidentified xiphidiocercariae. Larger snails were more likely to be infected and the infected snails were less likely to be fertile than uninfected ones.

<p>Sexual conflict occurs when female and male fitness interests diverge. In a social system characterized by aggressive sexual coercion and the risk of infanticide, female chimpanzees (Pan troglodytes) respond to this conflict by exhibiting an exaggerated sexual swelling that advertises sexual receptivity while concealing the exact timing of ovulation. Sexual swellings impose significant costs, yet can persist into pregnancy. Records from long-term studies of eastern chimpanzees (P. t. schweinfurthii) in Gombe National Park, TZ, and Kibale National Park, UG, provide data on postconception swellings, while data on group composition and behaviors such as mating, grooming, and aggression are drawn from the Gombe database only. Throughout, I use linear mixed models to simultaneously test multiple effects while controlling for repeated measures of individuals. In Chapter 1, I tested whether variation in females’ vulnerability to infanticide and aggression predicted the amount of swelling during pregnancy. In Chapter 2, I examined female-male relationships across reproductive states to ask whether females can better gain benefits and avoid costs by affiliating promiscuously with all males, or by investing in relationships with preferred males. Finally, I analyzed metabolites of reproductive hormones using urine samples from pregnant females in both populations to build a hormonal profile of postconception swellings. Swellings during pregnancy increase female-male association, and are caused by the same basic hormonal mechanism as preconception swellings, though they occur in a very different hormonal milieu. Females at greater risk of infanticide and intrasexual aggression swell more during pregnancy. Females mate promiscuously before conception, but during pregnancy and lactation, preferentially groom with males that are likely to protect them from aggression and infanticide. Based on these and other findings, I conclude that postconception swellings in chimpanzees are an adaptive response to sexual conflict.</p> / Dissertation

The mating behaviour and reproductive ecology of the big-handed crab Heterozius rotundifrons was studied at Kaikoura between November 1997 and December 1998. H. rotundifrons was found at mean densities of 7.6 per m² (± 1.4) within the middle and low shore levels and varied little between seasons. The variance! mean ratio indicated that males and females aggregated within these shore levels. The sex ratio was significantly female biased during the majority of the year. Allometric growth rates indicated that males and females reached sexual maturity at 11 mm carapace width (CW). In males, spermatozoa production occurred between 9-9.99 mm CW. Ovigerous females were present every month except February. The first broods of the year were produced in March which coincides with a decrease in the female gonado-somatic index (GSI). These broods were incubated for approximately nine months whereas broods produced in August were incubated for only five months. Female brood production appeared to be cyclical, alternating between a winter incubation period and a summer incubation period. The completed cycle takes approximately three years with two broods produced during the cycle. Fecundity increased with female size but egg mortality was quite high (19%). Instantaneous mortality rate increased with increasing brood development. Females mate when recently moulted (soft-shelled). Although females moulted through out the year, in small numbers, there was a peak in female moulting during October and November. The operational sex ratio (OSR) was male biased during all months of the year. Females released an attractant prior to moulting which initiated pre-copulatory mate guarding by the male. Once the female moulted, copulation occurred approximately 6 h later. Copulation lasted for approximately 3 h and was followed by a period of post-copulatory mate guarding. Males increased the duration of post-copulatory mate guarding if another male was present. Large males out competed small males for receptive females. Males used their large cheliped to subdue competitors and to provide protection for the soft female. Mate guarding was shown to reduce cannibalism from other females. Spermatozoa are packaged in spermatophores within the vas deferens of males but are quickly dehisced within the spermathecae (ventral-type) of newly mated females. Last male to copulate probably achieves the highest level of paternity. Postcopulatory mate guarding by the male was found and ejaculates were found in discrete packets within the spermatheca. Sperm competition appeared to be important because large males displaced small males during copulation, males left when a female was still receptive and the females could retain sperm between moults. It is concluded that H. rotundifrons probably has a polygynous mating system in which males compete for soft females (female centered competition)

A major challenge in plant ecology is in understanding how species strategies mediate interactions between the environment and fitness. Variation in niche strategies that affect phenological, physiological, and reproductive traits will allow species to partition resources differently in space and time, allowing for coexistence of many species and strategies within a community. How species differentially respond to variable environments will ultimately influence their population dynamics and geographic distribution. This dissertation approaches this topic from two perspectives: (a) examining the interaction between biogeography and variable demographic strategies in desert annual plants, and (b) examining the costs and benefits of contrasting reproductive strategies in co-occurring selfing and outcrossing desert annuals. Firstly, I tested the abundant center model to determine the role of range position on plant population dynamics. I examined how the geographic and climatic position of 13 desert annuals found at a common location, the Desert Laboratory at Tumamoc Hill in Tucson, Arizona, related to their demography over a 25-year time span. I found that species for which the Desert Laboratory was close to the center of their geographic range have less variable long-term survival and fecundity compared to species for which the Desert Laboratory was further from the center of their range. Secondly, I studied how related species with contrasting mating systems respond to variable environments to affect plant performance. In a three-year field study I investigated how inter-annual variation in plant reproductive phenology affects synchrony with pollinators and herbivores. Since selfing species are guaranteed to reproduce in the absence of pollinators, seasonal and annual variation in phenology resulted in less variable plant reproductive success compared to outcrossing species. Greater variation in reproduction in outcrossing species resulted from asynchrony in some years between plants and pollinators. In a greenhouse study examining the interaction between mating system and drought, I found that the physiological functioning and survival of outcrossing species was more strongly negatively affected by drought conditions, suggesting that selfing species have an advantage in more arid environments. These studies demonstrate how plant reproductive and physiological strategies can play a critical role in influencing fitness, population dynamics and geographic distribution.

Herbivory and plant competition affect sexual reproduction of plants in various ways. Exclusion of mule deer (Odocoileus hemionus) and cattle, removal of plant competition (both inter- and intraspecific), and all combinations of the above treatments were used to examine the individual and combined affects on Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) reproduction. Reproduction of Artemisia tridentata ssp. wyomingensis was divided into hierarchical levels of the number of: (1) modules per current-year ' s growth (CYG), (2) nodes per module, (3) inflorescence heads per node, (4) achenes per inflorescence head and (5) percent viable achenes. Counts at hierarchical levels were made to determine the level affected by the treatments. Deer herbivory significantly reduced reproduction at the reproductive-module-per-CYG-vegetative-biomass hierarchical level, while plant competition (both inter- and intraspecific) significantly reduced reproduction at the nodes-per-reproductive-module level and at the inflorescence-heads-per-node level. Cattle presence had neither a beneficial nor detrimental influence on reproduction during this two-year study. The combined effects of release from deer herbivory and from plant competition on reproduction was more than additive because these biotic interactions affected nested hierarchical levels.