Simon Tierney

• PhD
• Lecturer at Western Sydney University

Background Understanding connections between biodiversity and ecosystem services can be enhanced by shifting focus from species richness to functional trait-based approaches, that when paired with comparative phylogenetic methods can provide even deeper insights. We investigated the functional ecology and phylogenetic diversity of pollination servi...

Native bees augment pollination services in the Northern Hemisphere, especially cultivated apple crops, yet Southern Hemisphere contexts are poorly known. We observed the foraging behaviour of 69 354 invertebrate flower visitors in Australian orchards (two regions, 3 years) to assess the efficacy of pollination service (Peff). Native stingless bees...

Studying rapid biological changes accompanying the introduction of alien organisms into native ecosystems can provide insights into fundamental ecological and evolutionary theory. While powerful, this quasi-experimental approach is difficult to implement because the timing of invasions and their consequences are hard to predict, meaning that baseli...

Relatively little is known about regional variation in the native insects that visit and pollinate apples-a pollination-dependent and economically valuable global crop-in Australia. We undertook three studies on Pink Lady apple crops in two regions of Australia to 1) quantify the amount of apple pollen carried on the bodies of insects; 2) evaluate...

Subterranean habitats are generally very stable environments, and as such evolutionary transitions of organisms from surface to subterranean lifestyles may cause considerable shifts in physiology, particularly with respect to thermal tolerance. In this study we compared responses to heat shock at the molecular level in a geographically widespread,...

Subterranean habitats are generally very stable environments, and as such evolutionary transitions of organisms from surface to subterranean lifestyles may cause considerable shifts in physiology, particularly with respect to thermal tolerance. In this study we compared responses to heat shock at the molecular level in a geographically widespread,...

In the framework of neutral theory of molecular evolution, genes specific to the development and function of eyes in subterranean animals living in permanent darkness are expected to evolve by relaxed selection, ultimately becoming pseudogenes. However, definitive empirical evidence for the role of neutral processes in the loss of vision over evolu...

Diverse animals visit flowers but not all engage in pollination, and only behaviours involving stigmal contact result in successful pollination events. Ethological indices developed for sociobiological contexts (caste evolution) have unrealized potential to provide insights on pollination services but have not been applied in this context before. I...

Adaptive evolutionary theory argues that organisms with larger effective population size (N e) should have higher rates of adaptive evolution and therefore greater capacity to win evolutionary arm races. However, in some certain cases, species with much smaller N e may be able to survive besides their opponents for an extensive evolutionary time. N...

Transcriptome-based exon capture approaches, along with next-generation sequencing, are allowing for the rapid and cost-effective production of extensive and informative phylogenomic datasets from non-model organisms for phylogenetics and population genetics research. These approaches generally employ a reference genome to infer the intron-exon str...

The life cycle, nesting biology, and social organisation of a progressive provisioning allodapine bee, Exoneura angophorae, are detailed for the first time in the Greater Sydney region at the upper extreme of its altitudinal distribution. Nest collections of this montane population were undertaken monthly over an annual period to ascertain the life...

Adaptive evolutionary theory argues that organisms with larger effective population size (Ne) should have higher rates of adaptive evolution and therefore greater capacity to win evolutionary arm races. However, in some certain cases species with much smaller Ne may be able to survive beside their opponents for an extensive evolutionary time. Neutr...

The perception of cues and signals in visual, olfactory and auditory modalities underpins all animal interactions and provides crucial fitness-related information. Sensory organ morphology is under strong selection to optimize detection of salient cues and signals in a given signalling environment, the most well-studied example being selection on e...

Most subterranean animals are assumed to have evolved from surface ancestors following colonization of a cave system; however , very few studies have raised the possibility of "subterranean speciation" in underground habitats (i.e., obligate cave-dwelling organisms [troglobionts] descended from troglobiotic ancestors). Numerous endemic subterranean...

Neutral evolution theory predicts that genes specific to the development/function of eyes in subterranean animals will evolve under relaxed selection, ultimately becoming pseudogenes. Independently evolved (3-8 million years ago) subterranean beetle (Dytiscidae) species of Western Australia have converged on eye loss, providing a powerful system to...

Lateralisation of biological form and function are well known for vertebrates and are being increasingly documented among invertebrates in recent years. Behavioural lateralisation in insects, together with asymmetrical distributions of antennal sensilla, has been linked to the communication challenges faced by social, but not solitary, insects. Rec...

Synopsis: Two tribes of subterranean dytiscid diving beetles independently colonised groundwater systems of the Western Australian arid zone, a habitat transition that was most likely driven by the contraction of surface water bodies following late Neogene aridification of the Australian continent. These 'stygofauna' are now trapped within discret...

Wolbachia are intracellular bacteria that infect a wide range of arthropod and nematode hosts, whose reproduction they manipulate to increase rates of vertical transmission. Horizontal transmission between unrelated species also occurs; pathways and mechanisms are still under debate, but parasitoid wasps have been suggested as potential vectors. He...

Subterranean water beetles endemic to groundwater calcretes of Western Australia exhibit convergent traits typical of troglomorphic arthropods, including loss of eyes, pigmentation and wings. As these dytiscid species are estimated to have been isolated underground in permanent darkness for over three million years, it is predicted that they will c...

The comparison of social systems, particularly in closely related taxa, can be highly valuable to the understanding of social evolution. While much research has focused on the formation of hierarchies and eusocial organisation, it needs to be remembered that not all social systems are necessarily based on hierarchies. The allodapine bee Exoneurella...

Facultatively social species exhibit varying degrees of reproductive skew that provide valuable insights into the possible evolutionary forces shaping the origins of obligate eusocial colony organisation, wherein the majority of individuals (workers) forgo direct reproduction. Here we report aspects of the nesting biology of a semi-arid population...

Light represents one of the most reliable environmental cues in the biological world. In this review we focus on the evolutionary consequences to changes in organismal photic environments, with a specific focus on the class Insecta. Particular emphasis is placed on transitional forms that can be used to track the evolution from (1) diurnal to noctu...

There has been considerable debate surrounding the evolution of eusociality, which has recently increased in vigor with regard to what actually constitutes eusociality. Surprisingly, there has been little discussion on terminologies for describing social systems that are more-or-less egalitarian, yet such societies form an obvious contrast to eusoc...

Small carpenter bees (Ceratinini) are a key taxon to understanding the transition from subsocial to social behaviour, as all documented groups are long-lived and tend to their young periodically throughout development, though the behaviour of multiple lineages is little known. This study provides the first evidence for social nesting in three Neotr...

Evolution is often perceived as being a “directional” or “adaptive” process. We often think of species evolving to become stronger or faster, or to have sharper teeth, for example. And we tend to see this as being inherently progressive. But this is not always the case. Sometimes evolution can be regressive, such as when animals lose a trait. A cla...

The regressive evolution of eyes has long intrigued biologists yet the genetic underpinnings remain opaque. A system of discrete aquifers in arid Australia provides a powerful comparative means to explore trait regression at the genomic level. Multiple surface-ancestors from two tribes of diving beetles (Dytiscidae) repeatedly invaded these calcret...

The evolutionary origins of social parasitism are very unevenly distributed among ants, bees and wasps, but social parasite lineages are frequently close relatives of their host lineages. Two explanations for these relationships have been proposed: (1) initially, social species are more likely to become parasitic on relatively closely related socia...

Local environmental conditions can facilitate or preclude the development of eusocial colonies in insects that facultatively express behavioural-caste polyphenism. To explore how environmental variability relates to the expression of social behaviour, we collected 120 nests of the facultatively social sweat bee, Megalopta genalis (Halictidae: Augoc...

Evolutionary origins of highly eusocial organization involving morphological castes have been very rare, yet these origins have often led to enormous diversification and ecological success. This suggests that once an apparently severe selective barrier to highly eusocial behaviour is overcome, major new adaptive landscapes open up. One would theref...

Most bees rely on flowering plants and hence are diurnal foragers. From this ancestral state, dim-light foraging in bees requires significant adaptations to a new photic environment. We used DNA sequences to evaluate the phylogenetic history of the most diverse clade of Apoidea that is adapted to dim-light environments (Augochlorini: Megalopta, Meg...

Understanding how sterile worker castes in social insects first evolved is one of the supreme puzzles in social evolution. Here, we show that in the bee tribe Allodapini, the earliest societies did not entail a foraging worker caste, but instead comprised females sharing a nest with supersedure of dominance. Subordinates delayed foraging until they...

We present the first data on the nesting biology of Megalopta aegis and M. guimaraesi from southeastern Brazil. Nests were collected in the Área de Proteção Ambiental Água Limpa, Bauru, São Paulo state. Our data suggest that nest architecture is conserved throughout all species of Megalopta. Two nests of M. guimaraesi consisted of a single female w...

The social organization of allodapine bees has been described in detail for most genera, although there remains a notable gap for one major lineage, the genus Allodapula. Here, we provide the first detailed study of social organization in Allodapula dichroa. Colony sizes are small and the frequency of cooperative nesting is low compared with other...

Most bees forage for floral resources during the day, but temporal patterns of foraging activity vary extensively, and foraging in dim-light environments has evolved repeatedly. Facultative dim-light foraging behaviour is known in five of nine families of bees, while obligate behaviour is known in four families and evolved independently at least 19...

Allodapine bees have received attention because of their utility for studies of insect social evolution. The African genus Halterapis has been especially important because until very recently it was thought to contain non-social species. Owing to the extreme diversity in allodapine larval morphology, which is much greater than the variation in adul...

Bees of the genus Megalopta have gained attention as a result of their social nesting and nocturnal foraging. Seventeen nests of Meglaopta atra from the highlands of Chiriqui Province, Panama, were collected at the end of the dry season when brood rearing is expected to be at its peak. Most nests contained single females; within multifemale nests o...

The augochlorine (Halictidae) bee genus Xenochlora is the diurnal sister group to the nocturnal Megalopta, both of which are stem-nesting halictid bees. Here we present notes on the nesting biology and social behavior in four nests of Xenochlora nigrofemorata and one nest of X. ianthina from Madre de Dios, Peru. All nests contained multiple females...

It has been assumed that allodapine bees represent early stages in the evolution of social behaviour. Early studies suggested that sociality evolved from solitary forms, and that the solitary to social transition coincided with a transition from mass to progressive provisioning of brood. Recent studies challenge both of these assumptions, they sugg...

Chenoweth et al. MS Word document containing additional methodology employed in this study as well as additional figures and tables.

Phylogenetic studies on insect social parasites have found very close host-parasite relationships, and these have often been interpreted as providing evidence for sympatric speciation. However, such phylogenetic inferences are problematic because events occurring after the origin of parasitism, such as extinction, host switching and subsequent spec...

The major lineages of eusocial insects, the ants, termites, stingless bees, honeybees and vespid wasps, all have ancient origins (> or = 65 mya) with no reversions to solitary behaviour. This has prompted the notion of a 'point of no return' whereby the evolutionary elaboration and integration of behavioural, genetic and morphological traits over a...

The life cycle and social behaviour of an African allodapine bee, Braunsapis vitrea, was examined using nest contents data from thorn-nests in Acacia karroo in Limpopo Province, South Africa. The majority of B. vitrea colonies were subsocial, with 34% of nests collected containing more than one adult female. Although brood numbers increased with co...

Previous phylogenetic studies of the bee tribe Allodapini suggested a puzzling biogeographic problem: one of the key basal divergences involved separation of the southern African and southern Australian clades at a very early stage in allodapine evolution, but no taxa occur in the Palaearctic or Asian regions that might suggest a Laurasian dispersa...

Allodapine bees provide enormous material for comparative approaches to social evolution. Sociality varies widely among both genera and species. Some of this variation appears to be associated with ecological features, but some variation appears to shows signs of strong phylogenetic constraint. Importantly, several key life history traits also vary...

Aim A previous study of the allodapine bee genus Braunsapis suggested an African origin, with dispersal events into Madagascar and Asia, and from Asia into Australia. We re-examine the phylogeny of this genus, using an expanded set of taxa from Madagascar and Malawi and additional sequence data, in order to determine the number of dispersals and th...

Although the biology of most genera of allodapine bees is relatively well known, there are only fragmentary data on one African species of a basal genus, Halterapis, and there have been no studies of this genus from Madagascar where it is most speciose. We present the first account of nesting and social biology of a Malagasy species in this genus,...

Extreme AT bias in Hymenopteran mitochondrial genes have created difficulties for molecular phylogenetic analyses, especially for older divergences where multiple substitutions can erode signal. Heterogeneity in the evolutionary rates of different codon positions and different genes also appears to have been a major problem in resolving ancient div...

Recent molecular phylogenetic work on allodapine bees (Apidae, Xylocopinae), reported elsewhere, has shown that the tropical African genus Macrogalea is the most basal genus in the tribe Allodapini, and studies on this genus are likely to provide important insights into social evolution in the xylocopine bees. A new species, Macrogalea magenge from...

Recent phylogenetic studies based on DNA sequence data indicate that the tropical African bee genus Macrogalea is the sister group to the remaining extant allodapine fauna, whereas previously it was thought to be a distal group. This leads to some fundamental changes in our understanding of social evolution in the allodapines. Earlier studies sugge...

Summary: We present the first data on the social biology of the allodapine bee, Brevineura froggatti. Colony sizes are small, and only 12.5% of nests contained more than two females. Brood rearing occurs throughout the year, including winter, as it does in the other species of Brevineura studied to date. In both Brevineura species, per capita brood...

Australian allodapine bees provide excellent material for comparative approaches to understanding social evolution. The subgenus Exoneurella occupies a cladistically basal position in the Australian Exoneura group and comprises only four species. We describe sociality in one Exoneurella species, E. setosa, and combine this with other data to infer...

The allodapine bees are well suited for comparative studies of social evolution because of the wide variation in social behaviour within and between genera. There are three main clades in the endemic Australian genus Exoneura. Two groups (Exoneura sensu stricto and Exoneurella) have received extensive study. In this paper we provide the first detai...

The allodapine bee group Exoneurella may provide insights into ancestral forms of social organization in the Australian group of allodapine genera. Exoneurella occupies a cladistically basal position in the Exoneura group and differs from the other groups, which are largely Bassian in distribution, in having a predominantly Eyrean distribution. E....

Allodapine bees provide unique opportunities to examine potential selective factors underlying sociality in insects as they exhibit a range of social organizations and are found in a wide variety of habitats. In one allodapine genera, Exoneura, group living and social behaviour are common. These appear to be maintained by both direct and indirect f...