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121.
Abstract Female viviparous lizards from temperate locations in the Southern Hemisphere (New Zealand, Tasmania (Australia), South Africa and South America) often have reproductive activity spanning many months of the year. In contrast, vitellogenesis and pregnancy are often confined to the spring/summer months in viviparous species from temperate zones of the Northern Hemisphere. An extreme Southern Hemisphere example is the nocturnal common gecko from New Zealand, Hoplodactylus maculatus (Gray 1845), in which females exhibit biennial reproduction with pregnancy lasting up to 14 months in a cool‐climate population. Here, we examined whether such an extended reproductive cycle also occurs in a diurnal species, the jewelled gecko Naultinus gemmeus (McCann 1955), at a similar latitude. Palpation was used to assess reproductive condition non‐invasively. In contrast to the nearby higher‐altitude population of H. maculatus, N. gemmeus reproduces annually. Vitellogenesis occurs from autumn to spring in both species, but pregnancy ends after about 7 months in N. gemmeus. Birth occurs in the seemingly unpropitious season of mid‐ to late autumn, a pattern that may be unique for lizards from cool‐temperate zones. We hypothesize that there are major differences between populations of N. gemmeus and H. maculatus with respect to survival of autumn‐born neonates and/or costs to females from remaining pregnant over winter. Museum specimens of N. gemmeus support anatomical inferences from palpation; they also suggest that vitellogenesis may begin before the end of pregnancy (which may be essential to completing each reproductive cycle within a year) and that some populations may show gestation in utero over winter, as in H. maculatus. Extended gestation appears to be a common response to cool climates for Southern Hemisphere lizards that have independently evolved viviparity. 相似文献
122.
The importance of pre-thicket conifer plantations for nesting Hen Harriers Circus cyaneus in Ireland
MARK W. WILSON SANDRA IRWIN DAVID W. NORRISS STEPHEN F. NEWTON KEVIN COLLINS THOMAS C. KELLY & JOHN O'HALLORAN 《Ibis》2009,151(2):332-343
Hen Harriers Circus cyaneus are threatened across much of their range and their conservation requires appropriate habitat management. The locations of 148 Hen Harrier nests found in the Republic of Ireland during national breeding surveys in 2000 and 2005 were used to assess nest-site selection. The distribution of these nests was compared to distributions of randomly located points to investigate selection at the scale of the nest-site and landscape. The main nesting habitats selected were pre-thicket stage of first and, particularly, second rotation plantations, mostly of exotic conifers. There was no evidence that the area of post-closure plantations negatively affected Hen Harrier nest distribution. There was a positive correlation across study areas between changes in numbers of Hen Harrier nests between 2000 and 2005 and changes in the area of pre-thicket second rotation plantations over the same period. The overall effect of plantation forests on breeding Hen Harriers in Ireland therefore appears to be positive. However, this study did not consider the effects of plantation habitats on breeding success. Improved grassland was strongly avoided as a nesting habitat. Furthermore, after controlling for the influence of nesting habitat on nest location, landscapes with a high percentage cover of improved grassland were also avoided. Further agricultural intensification of grassland in areas where Hen Harriers breed is likely to have a negative impact on this species. These results are required for the development of management strategies for the conservation of this species. 相似文献
123.
The breeder's equation, which predicts evolutionary change when a phenotypic covariance exists between a heritable trait and fitness, has provided a key conceptual framework for studies of adaptive microevolution in nature. However, its application requires strong assumptions to be made about the causation of fitness variation. In its univariate form, the breeder's equation assumes that the trait of interest is not correlated with other traits having causal effects on fitness. In its multivariate form, the validity of predicted change rests on the assumption that all such correlated traits have been measured and incorporated into the analysis. Here, we (i) highlight why these assumptions are likely to be seriously violated in studies of natural, rather than artificial, selection and (ii) advocate wider use of the Robertson–Price identity as a more robust, and less assumption‐laden, alternative to the breeder's equation for applications in evolutionary ecology. 相似文献
124.
PAUL WILSON 《Biological journal of the Linnean Society. Linnean Society of London》1995,55(4):355-383
Selection on flowers has often been viewed as being particularly strict, constant, and responsible for species differences. Impatiens pallida and I . capensis flowers fit snugly around bees, leading one to expect a close relationship between floral morphology and pollination success. My studies on the amount of pollen removed from androecia and deposited on stigmas in single visits by bumblebees did not confirm this supposition. Trimming off parts of the floral vestibule with scissors and gluing in pleats had very little effect on die amount of pollen that bees moved. In reciprocal transfer experiments, flowers from different populations sometimes differed in the amount of pollen moved, but when the two species were compared in sympatry, pollen removal and deposition differed hardly at all. A comparison of the relationship between pollen movement and floral morphology among 15 populations showed that, although there was great heterogeneity in die amount of pollen moved, the observed differences were independent of floral morphology. None of this supports a belief in strong selection that fine-tunes the mechanical fit between bee and flower; selection for visitation success based on pollinator behaviour may have a much stronger influence on floral characters. 相似文献
125.
A new genus of phreatoicidean isopod (Crustacea) from the north Kimberley region, Western Australia 总被引:1,自引:0,他引:1
A new genus and species of phreatoicidean isopod, Crenisopus acinifer, has been collected from a freshwater spring in the northern Kimberley region of Western Australia. Empirical cladistic analysis of 10 exemplars of phreatoicidean genera found a single cladogram. The new genus and species assumed a basal position in the Phreatoicidea, placing it within the family Amphisopodidae sensu lata. This family, however, was not monophyletic in the preliminary cladogram, suggesting that the taxonomic structure of the suborder must be revised. The cladogram provided evidence for the monophyly of the Phreatoicidae and its New Zealand clade. The analysis suggested that clades of modern phreatoicideans diverged from one another during the Mesozoic Era after they entered fresh water, but prior to the fragmentation of East Gondwana. 相似文献
126.
The impacts of larval density and protease inhibition on feeding in medicinal larvae of the greenbottle fly Lucilia sericata
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M. R. WILSON Y. NIGAM W. JUNG J. KNIGHT D. I. PRITCHARD 《Medical and veterinary entomology》2016,30(1):1-7
Larval therapy, the therapeutic use of blowfly larvae to treat chronic wounds, is primarily used in debridement. There are, however, gaps in current knowledge of the optimal clinical application of the therapy and mechanisms of action in the debridement process. Using an artificial assay, two studies were undertaken to investigate these aspects of larval debridement by Lucilia sericata Meigen (Diptera: Calliphoridae); the first studied the effects of the density of larvae on tissue digestion and larval mass, and the second considered the effects on the same parameters of incorporating protease inhibitors into the feeding substrate. The total mass of tissue digested increased with larval density until saturation was observed at 5.0–7.5 larvae/cm2. This range was considered optimal as lower doses resulted in the removal of less tissue and higher doses offered no additional tissue removal and appeared to exacerbate competition for feeding. In the second study, increased protease inhibitor concentration led to significant decreases in tissue digestion and larval mass, suggesting that serine proteases, particularly trypsin, may play major roles in larval digestion. Such information is important in elucidating the main constituents that make up larval digestive products and may be significant in the development of new therapies. 相似文献
127.
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129.
ABSTRACT A new species of coccidium, Tyzzeria chalcides, is described from the ocellated skink, Chalcides ocellatus, from Egypt. Meronts occur in the epithelial cells of the bile ducts and gamonts within the epithelial cells of the gall bladder. Fully sporulated oocysts are cylindrical (L/W ratio 1.88) without a micropyle, oocyst residuum, or polar granule and contain eight spindle-shaped sporozoites and no sporocysts. Sporulation is completed within the gall bladder lumen. Comparison with other species of the genus found in reptiles indicates that it is a new species. 相似文献
130.
ABSTRACT. Four isosporan species are described from the small tree finch, Camarhynchus parvulus from Isabela Island on the Galapagos Archipelago. Isospora exigua n. sp. oocysts subspheroidal, one-layered, smooth, yellow-brown color, 20.4 × 20.1 (20-23 × 18-23) μm, with no micropyle, residuum, or polar body. Sporocysts ovoidal, 14 × 9.5 (13-15 × 8-10) μm, with small Stieda and substieda bodies and irregular-shaped residuum. Isospora rotunda n. sp. oocysts subspheroidal, single-layered, smooth, yellow-brown wall with large polar body and no micropyle or residuum, 20.9 × 20.8 (20-24 × 19-23) μm. Sporocysts ovoidal, 15 × 9.7 (13-16 × 9-10) μm with knob-like Stieda bodies, prominent substieda bodies and round residuum. Isospora fragmenta n. sp. oocysts subspheroidal with no micropyle or residuum but with many splinter-like polar granules and a smooth, colorless, single-layered wall, 25.3 × 24.2 (24-27 × 23-25) μm. Sporocysts piriform 15.4 × 11.5 (14-17 × 11-12) μm with knob-like Stieda bodies, prominent substieda bodies, and irregular-shaped residuum. Isospora temeraria n. sp. oocysts ellipsoidal with one polar body, no micropyle or residuum, and wall of a single layer, smooth, yellow-brown color, 25.4 × 21.1 (21-30 × 17-23) μm. Sporocysts piriform, 15 × 10 (14-15 × 9-11) μm with knob-like Stieda bodies, prominent substieda bodies, and a round residuum. One woodpecker finch, Cactospiza pallida, was found to be infected with I. exigua, and a warbler finch, Certhidea olivacea was infected with I. fragmenta. 相似文献