title: The mating systems and introgression of New Zealand fishing spiders (Dolomedes)

authors: Connolly, Simon

subjects: Behaviour

abstract: Mating systems describe the number of mates different sexes in a species have in their lifetime. Mating systems are key to sexual selection and the evolution of species, as a mating system sets the rules for future evolution and sexual conflict. Spiders show a wide variety of mating systems and extreme adaptations and behaviours are associated with the evolution of monogynous (males mate once in their life) mating systems, including males breaking their genitalia and sacrificing themselves to be eaten by their mate.

Another process that is highly influential on evolution is introgression, the movement of genes from one species to another. This generally occurs through species mating to produce hybrids which then facilitate gene transfer. Despite requiring two different species to interbreed, introgression is often not investigated through the lens of mating behaviours and how these can facilitate or limit introgression.

Dolomedes aquaticus and D. minor are fishing spiders endemic to New Zealand. Their mating systems and behaviour are undescribed, but members of this genus in other parts of the world are known for their extreme mating behaviour including obligate monogyny, spontaneous male death and sexual cannibalism. Previous genomic work on D. aquaticus and D. minor revealed a one-way and geographically limited introgression occurring between the two species. That is, genes are being transferred between the two species, but only via D. aquaticus females mating with D. minor males; and only in the extreme south of the two species’ shared range.

In this thesis I investigated the mating systems and introgression of D. aquaticus and D. minor, using laboratory experiments, field surveys, and 3D morphometrics. I found D. aquaticus females will generally only mate once, followed by a syndrome of aggression after mating, whilst males will mate multiply. D. minor mating is typified by low probability of mating for males and females, but potential for multiple mating in both sexes, rapid escape behaviour by males following copulation, and genital damage. I also found that the two species are able to meet outside of the Introgression Zone, making it unlikely that habitat plays a key role in the introgression. Instead, my results suggest behaviour plays a significant role in limiting the introgression, with male-choice controlling the geographic element and female-choice the one-way element. Using micro-computed tomography and 3D morphometrics I analysed the potential role of genital shape in this introgression. Whilst the genitalia of the two species were quantifiably different, there was little evidence that genital shape limits the introgression. 

The results of this thesis show that closely related species can have drastically different mating systems, showing the strong impact sexual selection can have on the behaviour of species. They also highlight the importance of behaviour to promoting and limiting introgression between species. Future work on these species should include investigation of sperm dynamics, the rapid copulation behaviour of D. minor, and testing the effectiveness of genital plugging to reduce sperm competition in D. minor.

text: The mating systems and introgression of New Zealand fishing spiders (Dolomedes) Mating systems describe the number of mates different sexes in a species have in their lifetime. Mating systems are key to sexual selection and the evolution of species, as a mating system sets the rules for future evolution and sexual conflict. Spiders show a wide variety of mating systems and extreme adaptations and behaviours are associated with the evolution of monogynous (males mate once in their life) mating systems, including males breaking their genitalia and sacrificing themselves to be eaten by their mate.

Another process that is highly influential on evolution is introgression, the movement of genes from one species to another. This generally occurs through species mating to produce hybrids which then facilitate gene transfer. Despite requiring two different species to interbreed, introgression is often not investigated through the lens of mating behaviours and how these can facilitate or limit introgression.

Dolomedes aquaticus and D. minor are fishing spiders endemic to New Zealand. Their mating systems and behaviour are undescribed, but members of this genus in other parts of the world are known for their extreme mating behaviour including obligate monogyny, spontaneous male death and sexual cannibalism. Previous genomic work on D. aquaticus and D. minor revealed a one-way and geographically limited introgression occurring between the two species. That is, genes are being transferred between the two species, but only via D. aquaticus females mating with D. minor males; and only in the extreme south of the two species’ shared range.

In this thesis I investigated the mating systems and introgression of D. aquaticus and D. minor, using laboratory experiments, field surveys, and 3D morphometrics. I found D. aquaticus females will generally only mate once, followed by a syndrome of aggression after mating, whilst males will mate multiply. D. minor mating is typified by low probability of mating for males and females, but potential for multiple mating in both sexes, rapid escape behaviour by males following copulation, and genital damage. I also found that the two species are able to meet outside of the Introgression Zone, making it unlikely that habitat plays a key role in the introgression. Instead, my results suggest behaviour plays a significant role in limiting the introgression, with male-choice controlling the geographic element and female-choice the one-way element. Using micro-computed tomography and 3D morphometrics I analysed the potential role of genital shape in this introgression. Whilst the genitalia of the two species were quantifiably different, there was little evidence that genital shape limits the introgression. 

The results of this thesis show that closely related species can have drastically different mating systems, showing the strong impact sexual selection can have on the behaviour of species. They also highlight the importance of behaviour to promoting and limiting introgression between species. Future work on these species should include investigation of sperm dynamics, the rapid copulation behaviour of D. minor, and testing the effectiveness of genital plugging to reduce sperm competition in D. minor.

year: 2024

title: Labourers' letters from Wellington to Surrey, 1840-1845: Lefebvre, Bernstein and pedagogies of appropriation

authors: Middleton, Sue

subjects: letter

abstract: Henri Lefebvre suggested that social researchers engage in 'the concrete analysis of rhythms' in order to reveal the 'pedagogy of appropriation (the appropriation of the body, as of spatial practice)'. Lefebvre's spatial analysis has influenced educational researchers, while the idea of 'pedagogy' has travelled beyond education. This interdisciplinary paper combines Lefebvre's analytical trilogy of perceived, conceived and lived spaces with Bernstein's 'pedagogical device' in an interrogation of historical documents. It engages in a 'rhythm analysis' of the New Zealand Company's 'pedagogical appropriation' of a group of agricultural labourers into its 'systematic colonisation scheme'. The temporal-spatial rhythms of the labourers' lives are accessible in nine surviving letters they wrote in Wellington and sent to Surrey between 1841 and 1844. By revealing how their bodies were 'traversed by rhythms rather as the “ether” is traversed by waves', we gain insight how bodies, space and the self are mutually constitutive and constituted.

text: Labourers' letters from Wellington to Surrey, 1840-1845: Lefebvre, Bernstein and pedagogies of appropriation Henri Lefebvre suggested that social researchers engage in 'the concrete analysis of rhythms' in order to reveal the 'pedagogy of appropriation (the appropriation of the body, as of spatial practice)'. Lefebvre's spatial analysis has influenced educational researchers, while the idea of 'pedagogy' has travelled beyond education. This interdisciplinary paper combines Lefebvre's analytical trilogy of perceived, conceived and lived spaces with Bernstein's 'pedagogical device' in an interrogation of historical documents. It engages in a 'rhythm analysis' of the New Zealand Company's 'pedagogical appropriation' of a group of agricultural labourers into its 'systematic colonisation scheme'. The temporal-spatial rhythms of the labourers' lives are accessible in nine surviving letters they wrote in Wellington and sent to Surrey between 1841 and 1844. By revealing how their bodies were 'traversed by rhythms rather as the “ether” is traversed by waves', we gain insight how bodies, space and the self are mutually constitutive and constituted.

year: 2010

title: The centrality of relationships for pedagogy: The Whanaungatanga Thesis

authors: Bishop, Russell

subjects: addressing educational disparities

abstract: Te Kotahitanga is a research and professional development project that seeks to reduce educational disparities between indigenous Māori students and their non-Māori peers in New Zealand secondary schools. While evidence of the impact of the project on teachers’ practice and the associated gains made by Māori students has been published previously, in order for the work of Te Kotahitanga to contribute to the broader educational research community, its pedagogical premises require empirical verification. To do so, we must first establish the validity of the pedagogical data by addressing two questions: (a) To what degree can the data gathered in the collaborative processes of Te Kotahitanga be used as a measure of pedagogical quality? and (b) Do these data support the foundational hypothesis of the project, that “extended family” relationships, as understood by Māori people when using the Māori term, whanaungatanga, are a central necessary component of overall pedagogical quality? This article provides an account of the context of this work then presents an analysis directed to these questions in turn. First, our analysis of the observational data gathered during the Te Kotahitanga professional development process is presented, followed by the measures that were developed for each of the main dimensions of pedagogy addressed in this work. Second, using these measures we present our analysis of the inter-relation among these dimensions of pedagogy to test the Whanaungatanga pedagogical thesis.

text: The centrality of relationships for pedagogy: The Whanaungatanga Thesis Te Kotahitanga is a research and professional development project that seeks to reduce educational disparities between indigenous Māori students and their non-Māori peers in New Zealand secondary schools. While evidence of the impact of the project on teachers’ practice and the associated gains made by Māori students has been published previously, in order for the work of Te Kotahitanga to contribute to the broader educational research community, its pedagogical premises require empirical verification. To do so, we must first establish the validity of the pedagogical data by addressing two questions: (a) To what degree can the data gathered in the collaborative processes of Te Kotahitanga be used as a measure of pedagogical quality? and (b) Do these data support the foundational hypothesis of the project, that “extended family” relationships, as understood by Māori people when using the Māori term, whanaungatanga, are a central necessary component of overall pedagogical quality? This article provides an account of the context of this work then presents an analysis directed to these questions in turn. First, our analysis of the observational data gathered during the Te Kotahitanga professional development process is presented, followed by the measures that were developed for each of the main dimensions of pedagogy addressed in this work. Second, using these measures we present our analysis of the inter-relation among these dimensions of pedagogy to test the Whanaungatanga pedagogical thesis.

year: 2013