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Assessing the morphological and physiological adaptations of the parasitoid wasp E chthrodesis lamorali for survival in an intertidal environment
- Owen, Candice A, Coetzee, Julia Angela, van Noort, Simon, Austin, Andrew D
- Authors: Owen, Candice A , Coetzee, Julia Angela , van Noort, Simon , Austin, Andrew D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123178 , vital:35412 , https://doi.org/10.1111/phen.12187
- Description: As a result of a variety of chemical, environmental, mechanical and physiological difficulties, insects that spend their entire life spans in the marine or intertidal region are relatively rare. The present study assesses whether morphological and physiological adaptations have evolved in a maritime parasitoidwasp species Echthrodesis lamorali Masner, 1968 (Hymenoptera: Platygastridae, Scelioninae), in response to environmental pressures on its respiratory functioning. Scanning electron and light microscopy of whole and sectioned specimens show the presence of structure-retaining taenidia in the tracheal tubes, although there is an absence of other major adaptations associated with the trachea or spiracles. Histological sectioning reveals the presence of unusual sacs in the female metasoma whose role is unknown, although they are hypothesized to most likely be linked to ovipositor control. Respirometry experiments illustrate the formation of a plastron when submerged, with the longevity of the wasps being increased by quiescence. The critical thermal range of E. lamorali is shown to be large: from −1.1 ∘C±0.16 to 45.7 ∘C±0.26 (mean±SE). Behavioural and physiological adaptations in E. lamorali appear to have evolved in response to exposure to the heterogeneous environmental conditions experienced within the intertidal zone.
- Full Text:
- Authors: Owen, Candice A , Coetzee, Julia Angela , van Noort, Simon , Austin, Andrew D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123178 , vital:35412 , https://doi.org/10.1111/phen.12187
- Description: As a result of a variety of chemical, environmental, mechanical and physiological difficulties, insects that spend their entire life spans in the marine or intertidal region are relatively rare. The present study assesses whether morphological and physiological adaptations have evolved in a maritime parasitoidwasp species Echthrodesis lamorali Masner, 1968 (Hymenoptera: Platygastridae, Scelioninae), in response to environmental pressures on its respiratory functioning. Scanning electron and light microscopy of whole and sectioned specimens show the presence of structure-retaining taenidia in the tracheal tubes, although there is an absence of other major adaptations associated with the trachea or spiracles. Histological sectioning reveals the presence of unusual sacs in the female metasoma whose role is unknown, although they are hypothesized to most likely be linked to ovipositor control. Respirometry experiments illustrate the formation of a plastron when submerged, with the longevity of the wasps being increased by quiescence. The critical thermal range of E. lamorali is shown to be large: from −1.1 ∘C±0.16 to 45.7 ∘C±0.26 (mean±SE). Behavioural and physiological adaptations in E. lamorali appear to have evolved in response to exposure to the heterogeneous environmental conditions experienced within the intertidal zone.
- Full Text:
Conservation implications of fine scale population genetic structure of Ficus species in South African forests:
- Deng, Jun-Yin, van Noort, Simon, Compton, Stephen G, Chen, Yan, Greeff, Jaco M
- Authors: Deng, Jun-Yin , van Noort, Simon , Compton, Stephen G , Chen, Yan , Greeff, Jaco M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163838 , vital:41074 , ttps://doi.org/10.1016/j.foreco.2020.118387
- Description: Genetic considerations are rarely applied in forest conservation management strategies, but forest fragmentation can reduce pollen and seed dispersal both between and within isolated fragments. Gene flow and immigration rates determine the extent to which individual plants are related to each other at different distances from themselves. This gradation in relatedness is known as a population's fine scale spatial genetic structure (SGS). Specifically, reduced but clumped immigration from distant fragments reduces fine scale SGS, whereas reduced gene flow within fragments increases fine scale SGS. In addition, non-random mortality caused by post-dispersal ecological processes can also affect SGS. We studied the effects of fragmentation on the fine scale SGS of Ficus species with different habitat preferences and distributional ranges in an archipelago of South African forest patches.
- Full Text:
- Authors: Deng, Jun-Yin , van Noort, Simon , Compton, Stephen G , Chen, Yan , Greeff, Jaco M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163838 , vital:41074 , ttps://doi.org/10.1016/j.foreco.2020.118387
- Description: Genetic considerations are rarely applied in forest conservation management strategies, but forest fragmentation can reduce pollen and seed dispersal both between and within isolated fragments. Gene flow and immigration rates determine the extent to which individual plants are related to each other at different distances from themselves. This gradation in relatedness is known as a population's fine scale spatial genetic structure (SGS). Specifically, reduced but clumped immigration from distant fragments reduces fine scale SGS, whereas reduced gene flow within fragments increases fine scale SGS. In addition, non-random mortality caused by post-dispersal ecological processes can also affect SGS. We studied the effects of fragmentation on the fine scale SGS of Ficus species with different habitat preferences and distributional ranges in an archipelago of South African forest patches.
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