Barbara York Main

Bio: Barbara York Main is an academic researcher from University of Western Australia. The author has contributed to research in topics: Mygalomorphae & Genus. The author has an hindex of 14, co-authored 35 publications receiving 582 citations.

Deep phylogeographic structuring of populations of the trapdoor spider Moggridgea tingle (Migidae) from southwestern Australia: evidence for long‐term refugia within refugia

Abstract: Southwestern Australia has been recognized as a biodiversity hot spot of global significance, and it is particularly well known for its considerable diversity of flowering plant species. Questions of interest are how this region became so diverse and whether its fauna show similar diverse patterns of speciation. Here, we carried out a phylogeographic study of trapdoor spiders (Migidae: Moggridgea), a presumed Gondwanan lineage found in wet forest localities across southwestern Australia. Phylogenetic, molecular clock and population genetic analyses of mitochondrial (mtDNA) COI gene and ITS rRNA (internal transcribed spacer) data revealed considerable phylogeographic structuring of Moggridgea populations, with evidence for long-term (>3 million years) isolation of at least nine populations in different geographic locations, including upland regions of the Stirling and Porongurup Ranges. High levels of mtDNA divergence and no evidence of recent mitochondrial gene flow among valley populations of the Stirling Range suggest that individual valleys have acted as refugia for the spiders throughout the Pleistocene. Our findings support the hypothesis that climate change, particularly the aridification of Australia after the late Miocene, and the topography of the landscape, which allowed persistence of moist habitats, have been major drivers of speciation in southwestern Australia.

Predicting the post-fire responses of animal assemblages: testing a trait-based approach using spiders.

Abstract: 1 Developing a predictive understanding of how species assemblages respond to fire is a key conservation goal In moving from solely describing patterns following fire to predicting changes, plant ecologists have successfully elucidated generalizations based on functional traits Using species traits might also allow better predictions for fauna, but there are few empirical tests of this approach 2 We examined whether species traits changed with post-fire age for spiders in 27 sites, representing a chronosequence of 0-20 years post-fire We predicted a priori whether spiders with ten traits associated with survival, dispersal, reproduction, resource-utilization and microhabitat occupation would increase or decrease with post-fire age We then tested these predictions using a direct (fourth-corner on individual traits and composite traits) and an indirect (emergent groups) approach, comparing the benefits of each and also examining the degree to which traits were intercorrelated 3 For the seven individual traits that were significant, three followed predictions (body size, abundance of burrow ambushers and burrowers was greater in recently burnt sites); two were opposite (species with heavy sclerotisation of the cephalothorax and longer time to maturity were in greater abundance in long unburnt and recently burnt sites respectively); and two displayed response patterns more complex than predicted (abdominal scutes displayed a U-shaped response and dispersal ability a hump shaped curve) However, within a given trait, there were few significant differences among post-fire ages 4 Several traits were intercorrelated and scores based on composite traits used in a fourth-corner analysis found significant patterns, but slightly different to those using individual traits Changes in abundance with post-fire age were significant for three of the five emergent groups The fourth-corner analysis yielded more detailed results, but overall we consider the two approaches complementary 5 While we found significant differences in traits with post-fire age, our results suggest that a trait-based approach may not increase predictive power, at least for the assemblages of spiders we studied That said, there are many refinements to faunal traits that could increase predictive power

Where have all the spiders gone? The decline of a poorly known invertebrate fauna in the agricultural and arid zones of southern Australia

Abstract: Michael G Rix, Joel A Huey, Barbara Y Main, Julianne M Waldock, Sophie E Harrison, Sarah Comer, Andrew D Austin and Mark S Harvey

Habitat preferences of the urban wall spider Oecobius navus (Araneae, Oecobiidae)

Abstract: To assess the relative impact of a range of habitat variables on spider abundance, field and laboratory experiments were conducted on populations of the urban wall spider Oecobius navus in suburban Perth, Western Australia. Habitat characteristics investigated were: substrate type, wind speed, rainfall, sunlight exposure, relative humidity, air temperature, substrate temperature, artificial lighting and prey type/abundance. In the field, O. navus was found to be associated with high humidity, low air tempera- ture and shelter from sunlight and rainfall. Oecobius navus was more abundant at sites with greater prey abundance. The most common prey item was the red meat ant Iridomyrmex chasei. Juvenile spiders were more abundant than adult spiders; however, patterns between spider abundance and habitat variables were similar for both adults and juveniles. Laboratory experiments showed that O. navus preferred to build webs on wooden substrates, and pitted limestone walls. These findings indicate that O. navus may be vulnerable to desiccation and/or thermal stress, and thus survives better on sheltered walls.

Sex ratio in the social spider Diaea socialis (Araneae: Thomisidae)

Abstract: Sex ratio data from embryos and adults are compared in the social thomisid Diaea socialis. The relative proportions of males and females do not differ significantly between the two data sets, indicating tha t a sex ratio bias already exists at the time of fertilization. A statistical comparison with published data for the theridiid Anelosimus eximiusshows a different ratio but similar pattern for the two types of data . A molecular procedure for determining whether the overproduction of females results from a bias in the sperm or differentia l success of sperm in fertilizationis described. In those social spiders where the adult sex rati o is known, it is female-biased (Buskirk 1981 ; Voll- rath 1986). However, Fisher's principle (Fisher 1930) predicts that selectionwill favor an equal parental investment in offspring of both sexes . It would follow, then, that any bias in sex rati o should result from forces acting after dispersal. On the basis of the correlation between sex rati o and social behavior it would seem reasonable t hypothesize that the two phenomena are in som e way causally linked. Skewed sox ratios have sim - ilarly been reported in colonies ofDiaea sociali s Main, with an observed male :female ratio o f 0.2126 (Main 1988).

Does conservation on farmland contribute to halting the biodiversity decline

Abstract: Biodiversity continues to decline, despite the implementation of international conservation conventions and measures. To counteract biodiversity loss, it is pivotal to know how conservation actions affect biodiversity trends. Focussing on European farmland species, we review what is known about the impact of conservation initiatives on biodiversity. We argue that the effects of conservation are a function of conservation-induced ecological contrast, agricultural land-use intensity and landscape context. We find that, to date, only a few studies have linked local conservation effects to national biodiversity trends. It is therefore unknown how the extensive European agri-environmental budget for conservation on farmland contributes to the policy objectives to halt biodiversity decline. Based on this review, we identify new research directions addressing this important knowledge gap.

The Evolution of Sociality in Spiders

Abstract: Publisher Summary This chapter discusses the occurrence of group living in spiders. Group living has arisen in spiders in basically two different forms. Cooperative or nonterritorial permanent‐social species are the main focus of the chapter. The form of group living in spiders has been termed “colonial” or “communalterritorial.” Colonial species have been likened to foraging flocks of birds and are described as foraging societies. Social spiders can be viewed as an ideal evolutionary experiment with independent replicates, both within and across several families. The designation of species as nonterritorial permanent‐social and nonterritorial periodic‐social applies to groups of traits that generally occur together. The chapter illustrates that, as this terminology is also somewhat unwieldy, for convenience it revert to the commonly used shorthand designations of social and subsocial, for nonterritorial permanent‐social and territorial periodic‐social, respectively.