Search

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 baseline pre-invasion data are often missing. Exceptionally, the eventual arrival of Varroa destructor (hereafter Varroa) in Australia has been predicted for decades. Varroa is a major driver of honeybee declines worldwide, particularly as vectors of diverse RNA viruses. The detection of Varroa in 2022 at over a hundred sites poses a risk of further spread across the continent. At the same time, careful study of Varroa's spread, if it does become established, can provide a wealth of information that can fill knowledge gaps about its effects worldwide. This includes how Varroa affects honeybee populations and pollination. Even more generally, Varroa invasion can serve as a model for evolution, virology and ecological interactions between the parasite, the host and other organisms.

The genus Leptospermum (Myrtaceae) is widespread in Australia and contains several species that are of increasing interest to produce bioactive honey. Here, we used the Maxent algorithm to investig...

Biological sources of carbon sequestration such as revegetation have been highlighted as important avenues to combat climate change and meet global targets by the global community including the Paris Climate Agreement. However, current and projected carbon prices present a considerable barrier to broad‐scale adoption of tree planting as a key mitigation strategy. One avenue to provide additional economic and environmental incentives to encourage wider adoption of revegetation is the bundling or stacking of additional co‐beneficial ecosystem services that can be realized from tree planting. Using the World's largest land‐based carbon credit trading scheme, the Australian Emissions Reduction Scheme (ERF), we examine the potential for three pairs of ecosystem services, where the carbon sequestration value of land use change is paired with an additional co‐benefit with strong prospects for local tangible benefits to land owners/providers. Two cases consider agricultural provisioning values that can be realized by the landowners in higher returns: increased pollination services and reduced lamb mortality. The third case examined payments for tree plantings along riparian buffers, with payments to farmers by a water utility who realizes the benefit from reduced treatment cost due to water quality improvements. Economic incentives from these co‐benefit case studies were found to be mixed, with avoided treatment costs from water quality paired with carbon payments the most promising, while pollination and reduced lamb mortality paired with carbon payments were unable to bridge the economic gap except under the most optimistic assumptions. We conclude that the economics case for significant land use change are likely to be geographically dispersed and only viable in relatively niche landscape positions in high establishment, high opportunity cost areas even when carbon payments are augmented with the value of co‐benefits classified as providing direct and local benefits. Refereed/Peer-reviewed

The species in the subgenus Amegilla (Asaropoda) are revised. Species delineation was decided based on diagnostic morphological characters as well as an incomplete phylogeny based on mitochondrial cytochrome oxidase 1 sequence data. Strong support was obtained for separating the Australian species of Amegilla into the three subgenera previously proposed on the basis of morphology. The subgenus Asaropoda was found to comprise 21 species, including ten new species: A. albiclypeata Leijs, sp. nov., A. aurantia Leijs, sp. nov., A. batleyi Leijs, sp. nov., A. crenata Leijs, sp. nov., A. griseocincta Leijs, sp. nov., A. incognita Leijs, sp. nov., A. nitidiventris Leijs, sp. nov., A. scoparia Leijs, sp. nov., A. xylocopoides Leijs, sp. nov., and A. youngi Leijs, sp. nov. The subspecies A. preissi frogatti is raised to species level, and 16 new synonymies are proposed. Keys to the species of both sexes and descriptions or redescriptions are provided. Distribution maps, data on flower visitation and phenology are given.

Due to local extinction, the endangered green carpenter bee (Xylocopa aerata) has a disjunct distribution in the southeast of Australia. The species relies on dead softwood from a small selection of plant species for making its nests. Habitat fragmentation, combined with deleterious fire events, is thought to have negatively impacted on nesting substrate availability and recolonisation chances. Here, we use MaxEnt algorithm to model both the current distribution and the effect of climate change scenarios on the distribution of both X. aerata and four plant species that provide most of its nesting substrate: Banksia integrifolia, B. marginata, Xanthorrhoea arborea and Xanthorrhoea semiplana subsp. tateana. The annual mean temperature is the strongest climatic predictor of the distribution of X. aerata and its host plants. The modelled distribution of the bee under current climatic conditions indicates that climatic factors are unlikely to cause local extinctions. In all future scenarios, suitable areas for X. aerata and each of its nesting hosts are expected to contract towards the southeast of mainland Australia. The suitability of Kangaroo Island for the bee and its current local current host species is maintained in all scenarios, while Tasmania will become increasingly suitable for all species. The Grampians National Park in western Victoria, where the bee species were last seen outside of its current range (in the 1930s), is predicted to remain suitable for X. aerata and several host plants under all scenarios. Therefore, this relatively large area of native vegetation may be a good case study for re‐introduction as part of future conservation efforts.

Honey bees,Apis mellifera, have been implicated as vectors of plant pathogens. However, the survival of spores of plant pathogenic fungi through the digestive tract of workers has not been investigated. As workers defecate outside the hive, transport of hives could give rise to biosecurity concerns if fungal spores remain viable following passage through the digestive tract. To determine the likelihood that honey bees serve as vectors, this study investigated the viability of spores ofBotrytis cinereaandColletotrichum acutatumafter passing through the digestive tract of summer and autumn worker bees. For both fungi, the mean viability of spores in faeces suspensions was less than one percent of the initial dose fed to the bees. Although survival was low, the large number of workers per hive implies a high probability of transmission of viable spores through honey bee faeces. Hence, in the case of economically important fungal diseases, transported hives could be a source of inoculum and quarantine restrictions should be considered.

The 2019-2020 Australian Black Summer wildfires demonstrated that single events can have widespread and catastrophic impacts on biodiversity, causing a sudden and marked reduction in population size for many species. In such circumstances, there is a need for conservation managers to respond rapidly to implement priority remedial management actions for the most-affected species to help prevent extinctions. To date, priority responses have been biased towards high-profile taxa with substantial information bases. Here, we demonstrate that sufficient data are available to model the extinction risk for many less well-known species, which could inform much broader and more effective ecological disaster responses. Using publicly available collection and GIS datasets, combined with life-history data, we modelled the extinction risk from the 2019-2020 catastrophic Australian wildfires for 553 Australian native bee species (33% of all described Australian bee taxa). We suggest that two species are now eligible for listing as Endangered and nine are eligible for listing as Vulnerable under IUCN criteria, on the basis of fire overlap, intensity, frequency, and life-history traits: this tally far exceeds the three Australian bee species listed as threatened prior to the wildfire. We demonstrate how to undertake a wide-scale assessment of wildfire impact on a poorly understood group to help to focus surveys and recovery efforts. We also provide the methods and the script required to make similar assessments for other taxa or in other regions.

Honey bees, Apis mellifera, actively collect a range of materials including pollen and fungal spores. However, the interaction between honey bees and fungal spores is largely unexplored. Therefore, this study aimed to assess the corbicular contents of workers foraging on zucchini leaves severely affected by powdery mildew. The dimensions (length and width) of conidia removed from the corbiculae of honey bee workers and from the zucchini leaves were similar and conidia matched the description of Podosphaera xanthii, the causal agent of powdery mildew of cucurbits. Our findings that corbicular loads comprised only conidia of P. xanthii confirm that honey bees exhibited constancy, just as they almost always forage on a single species of flower per foraging trip, and highlight the importance of understanding the behaviour of honey bee workers in regards to the collection of fungal spores.

Unmanaged, or feral, honey bees can be abundant in Australian agricultural landscapes and provide substantial, but unquantified, crop pollination services. This makes these production syste...

Pollinators are globally recognised for their role in ecosystem function and reports of pollinator declines are a source of public and academic concern. However, pollinator decline is often erroneously interpreted as if crop pollination services are under threat, which can lead to misguided efforts to protect introduced and/or widespread crop pollinating species that are not in decline, without addressing the needs of other imperilled species. The honey bee (Apis mellifera L.) in particular has widespread recognition for its role as an integral agricultural pollinator and is the focus of many pollinator campaigns. However, we argue outside of their native range that honey bees are inappropriate as umbrella or flagship species for the conservation of pollinators.

The conversion of natural vegetation to agriculture is a leading cause of biodiversity decline globally, and can impact negatively on ecosystem services such as pollination. Global meta-analyses find that crop visitation by wild pollinators increases with the amount of natural or semi-natural vegetation in the surrounding landscape. However, these studies typically test the effect of one land cover type, rather than comparing multiple land cover types, and so do not provide information about the land cover arrangements that maximize crop visitation by wild pollinators. We sampled wild bee visitors to apple flowers in 2017 and 2018, and weeds and native plants in apple orchards in 2018, along landscape gradients of native vegetation and non-crop agricultural cover (open grassy areas, grazed or ungrazed) across three widely-separate agricultural regions of southeast Australia. We compared different land cover types as predictors of wild bee visitation to apple orchards, classifying non-crop land cover as: 1) ‘natural vegetation’ (NV), 2) ‘open grassy areas’ (OGA), and 3) ‘natural vegetation plus open grassy areas’ (NVOGA). The dominant flower-visiting wild bees in apple orchards in all regions were soil-nesting species of Halictidae that appear to be capable of exploiting open areas cleared for agriculture; however, even these taxa were rare or absent from orchards in some regions and years. Wild bee visitation to apples was best predicted by OGA in 2017 (positive association), but no land cover type in 2018, while visitation to weeds and native plants increased with both OGA and NV. Comparing different ways of classifying non-crop land cover is important for identifying land management strategies that maximize crop pollination services. However, managing land cover for wild bees may have negligible impacts on apple pollination in southeast Australia where wild bees are often rare in orchards, exhibit between-year variation in land cover associations, and are vastly outnumbered by honeybees (> 90% of visits to apple flowers).

Background Eretmocerus warrae (Hymenoptera: Aphelinidae) is a parasitoid of the glasshouse whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae). Here, we compare its potential as a biological control agent at high temperatures to that of Encarsia formosa (Hymenoptera: Aphelinidae), a wasp which is widely sold for control of T. vaporariorum. Results Eretmocerus warrae attained the highest estimated developmental rate at 31.4 °C and the maximum oviposition rate at 30.5 °C. Developmental times of E. warrae at fluctuating temperatures that simulate night-day patterns were similar to those predicted based on constant temperatures. Above the optimum temperature, E. warrae tolerated higher constant temperatures than En. formosa during development and as adults. Using a ramping temperature approach, the critical thermal maximum for adult E. warrae was significantly higher than that of adult En. formosa. Conclusion Eretmocerus warrae is better adapted to high temperatures than En. formosa, and could therefore be a complementary or superior biological control agent during summer months in hot regions. © 2018 Society of Chemical Industry.

Despite progress in recent decades, the conservation management of insects and allied invertebrates in Australia is challenging and remains a formidable task against a background of poor taxonomic and biological knowledge, limited resources (funds and scientific expertise) and a relatively low level of community engagement, education and awareness. In this review, we propose a new, strategic national approach for the conservation of insects and allied invertebrates in Australia to complement and build on existing actions and increase awareness with the general public and government. A review of all species listed under relevant State and Territory Acts, national legislation (EPBC Act) and on international lists (IUCN Red List) indicated that of the 285 species currently listed under these conservation schedules, 10 (3%) are considered extinct, 204 (72%) threatened (Critically Endangered, Endangered or Vulnerable) and 71 (25%) are classified as other (Threatened, Near Threatened, Rare or Least Concern). Comparison of the geographic ranges of listed species in relation to bioregions (IBRA regions) shows a striking discordance in spatial representation across the Australian landscape, reflecting an ad hoc approach to threatened species conservation and the concentration of invertebrate biologists in urban centres of temperate coastal Australia. There is a positive relationship between the number of threatened species and extent of protection according to the National Reserve System within each IBRA region, exemplifying the anomaly in spatial representativeness of listed species. To overcome these shortfalls, we propose a novel educational, regional approach based on selecting, for each of the 89 IBRA regions, a relatively small set of ‘flagship taxa’ (threatened species and/or ‘iconic’ species of high scientific/social value), which are then promoted and/or nominated for listing by the scientific community. Such species could be adopted by local community groups whereby a community‐based regional approach would ensure spatial representativeness of insect conservation across the entire Australian continent. This novel approach may ultimately provide a better strategy for the conservation management of habitats and threatened ecological communities, reducing extinction risk of threatened species and addressing key threatening processes. Members of the Australian entomological community are strongly encouraged to nominate candidate taxa as flagship species for wider promotion and/or listing nationally under the EPBC Act.

Protective covers (i.e., glasshouses, netting enclosures, and polytunnels) are increasingly used in crop production to enhance crop quality, yield, and production efficiency. However, many protected crops require insect pollinators to achieve optimal pollination and there is no consensus about how best to manage pollinators and crop pollination in these environments. We conducted a systematic literature review to synthesise knowledge about the effect of protective covers on pollinator health and pollination services and identified 290 relevant studies. Bees were the dominant taxon used in protected systems (90%), represented by eusocial bees (e.g., bumble bees (Bombus spp.), honey bees (Apis spp.), stingless bees (Apidae: Meliponini)) and solitary bees (e.g., Amegilla spp., Megachile spp., and Osmia spp.). Flies represented 9% of taxa and included Calliphoridae, Muscidae, and Syrphidae. The remaining 1% of taxa was represented by Lepidoptera and Coleoptera. Of the studies that assessed pollination services, 96% indicate that pollinators were active on the crop and/or their visits resulted in improved fruit production compared with flowers not visited by insects (i.e., insect visits prevented, or flowers were self- or mechanically pollinated). Only 20% of studies evaluated pollinator health. Some taxa, such as mason or leafcutter bees, and bumble bees can function well in covered environments, but the effect of covers on pollinator health was negative in over 50% of the studies in which health was assessed. Negative effects included decreased reproduction, adult mortality, reduced forager activity, and increased disease prevalence. These effects may have occurred as a result of changes in temperature/humidity, light quality/quantity, pesticide exposure, and/or reduced access to food resources. Strategies reported to successfully enhance pollinator health and efficiency in covered systems include: careful selection of bee hive location to reduce heat stress and improve dispersal through the crop; increased floral diversity; deploying appropriate numbers of pollinators; and manipulation of flower physiology to increase attractiveness to pollinating insects. To improve and safeguard crop yields in pollinator dependent protected cropping systems, practitioners need to ensure that delivery of crop pollination services is compatible with suitable conditions for pollinator health.

Losses of honey bees have been repeatedly reported from many places worldwide. The widespread use of synthetic pesticides have led to concerns regarding their environmental fate and their effects on pollinators. While the impact of insecticides on bees has received substantial attention, relatively little is known about the consequences of the use of non-insecticidal pesticides for bee health, and no comprehensive review is available. Here, we used a standardized method to review scientific papers with classifiable outcomes on bee health of non-insecticidal applications (i.e., fungicides, herbicides, and other non-specific pesticides) and their interactive effect on bee health. We comprehensively summarize for the first-time overall outcomes and outcomes per bee species, as well as the individual and combinatory outcomes for specific chemicals, types, and classes. The available information indicates minimal impact for nearly all fungicides and fungicide combinations, confirming that, with some exceptions, fungicides are not as harmful as insecticides. However, when interactions were found, fungicide-fungicide combinations were just as harmful as fungicide-insecticide interactions. Herbicide and other groups were more harmful than fungicides and showed similar interactive effects. Because exposure to multiple chemicals is likely to be common in most agricultural landscapes, we recommend that the detrimental interactive effects through co-application be made available on pesticide labels.

The Australian bees in the subgenera Notomegilla and Zonamegilla of the genus Amegilla are revised. Commonly in Australia the species in these subgenera are called blue-banded bees, although not all species have blue bands. A phylogeny based on mitochondrial cytochrome oxidase 1 sequence data was used to delineate the species and a set of morphological criteria was developed for species identification. Strong support was obtained for separating the Australian species into the three subgenera previously proposed on the basis of morphology. Two species, are recognised in the subgenus Notomegilla and eleven new synonymies are proposed. Twelve Australian species are recognised in the subgenus Zonamegilla including four new species: indistincta, karlba, paeninsulae and viridicingulata, and twenty new synonymies are proposed. Keys to the species of both sexes and descriptions or redescriptions of all species are provided. Distribution maps, data on flower visitation and phenology are given.

Bees are known mainly by one eccentric species, the honey bee, and many people do not realize that there are some 20,000 species of bees, most of them living solitarily. Although honey bees and oth...

The species in the subgenus Amegilla (Asaropoda) are revised. Species delineation was decided based on diagnostic morphological characters as well as an incomplete phylogeny based on mitochondrial cytochrome oxidase 1 sequence data. Strong support was obtained for separating the Australian species of Amegilla into the three subgenera previously proposed on the basis of morphology. The subgenus Asaropoda was found to comprise 21 species, including ten new species: A. albiclypeata Leijs, sp. nov., A. aurantia Leijs, sp. nov., A. batleyi Leijs, sp. nov., A. crenata Leijs, sp. nov., A. griseocincta Leijs, sp. nov., A. incognita Leijs, sp. nov., A. nitidiventris Leijs, sp. nov., A. scoparia Leijs, sp. nov., A. xylocopoides Leijs, sp. nov., and A. youngi Leijs, sp. nov. The subspecies A. preissi frogatti is raised to species level, and 16 new synonymies are proposed. Keys to the species of both sexes and descriptions or redescriptions are provided. Distribution maps, data on flower visitation and phenology are given.

Goniocolletes comatus Maynard, 2013 is redescribed. Goniocolletes wanni sp. n. and the male of Trichocolletes luteorufus Batley & Houston, 2012 are described.

Many bees collect pollen by grasping the anthers of a flower and vibrating their flight muscles at high frequencies—a behavior termed sonication, or buzz-pollination. Here we compare buzz-pollination on Solanum lycopersicum (cherry tomatoes) by two bees that fill similar niches on different continents—in Australia, Amegilla murrayensis (blue-banded bee), and in North America, Bombus impatiens (bumblebee). We collected audio recordings of buzz-pollination and quantified the frequency and length of buzzes, as well as the total time spent per flower. We found that A. murrayensis buzzes at significantly higher frequencies (~350 Hz) than B. impatiens (~240 Hz) and flaps its wings at higher frequencies during flight. There was no difference in the length of a single buzz, but A. murrayensis spent less time on each flower, as B. impatiens buzzed the flower several times before departing, whereas A. murrayensis typically buzzed the flower only once. High-speed videos of A. murrayensis during buzz-pollination revealed that its physical interaction with the flower differs markedly from the mechanism described for Bombus and other bees previously examined. Rather than grasping the anther cone with its mandibles and shaking, A. murrayensis taps the anther cone with its head at the high buzzing frequencies generated by its flight muscles. This unique behavior, combined with its higher buzzing frequency and reduced flower visit duration, suggests that A. murrayensis may be able to extract pollen more quickly than B. impatiens, and points to the need for further studies directly comparing the pollination effectiveness of these species.

For molecular insect identification, amplicon sequencing methods are recommended because they offer a cost-effective approach for targeting small sets of informative genes from multiple samples. In this context, high-throughput multilocus amplicon sequencing has been achieved using the MiSeq Illumina sequencing platform. However, this approach generates short gene fragments of

Bee pollination is critical for improving productivity of one third of all plants or plant products consumed by humans. The health of honey bees is in decline in many countries worldwide, and RNA viruses together with other biological, environmental and anthropogenic factors have been identified as the main causes. The rapid genetic variation of viruses represents a challenge for diagnosis. Thus, application of deep sequencing methods for detection and analysis of viruses has increased over the last years. In this study, we leverage from the innate Dicer-2 mediated antiviral response against viruses to reconstruct complete viral genomes using virus-derived small interfering RNAs (vsiRNAs). Symptomatic A. mellifera larvae collected from hives free of Colony Collapse Disorder (CCD) and the parasitic Varroa mite (Varroa destructor) were used to generate more than 107 million small RNA reads. We show that de novo assembly of insect viral sequences is less fragmented using only 22 nt long vsiRNAs rather than a combination of 21–22 nt small RNAs. Our results show that A. mellifera larvae activate the RNAi immune response in the presence of Sacbrood virus (SBV). We assembled three SBV genomes from three individual larvae from different hives in a single apiary, with 1–2% nucleotide sequence variability among them. We found 3–4% variability between SBV genomes generated in this study and earlier published Australian variants suggesting the presence of different SBV quasispecies within the country.

Carpenter bees are the main pollinators of passion fruit, a crop classified as vulnerable to pollinator decline because it is strictly self-incompatible. We investigated cost-effective management strategies to increase the presence of female carpenter bees in passion fruit orchards by using trap-nests in bee shelters. Transfers of nests containing females of X. frontalis and X. grisescens between different sites were significantly more successful when the nests contained brood cells. Supplying a bee shelter with a combination of suitably sized empty bamboo stalks and active nests of carpenter bees can increase the population of actively nesting bees by >200% during the course of 23 mo, as a consequence of the emergence of brood from the introduced nests and the attraction of bees from the surroundings. In conclusion, our methods lead to improved success of introducing, increasing and maintaining carpenter bees populations for the pollination of passion fruit crops.

International audience; AbstractPollen of wind-pollinated plants such as grapevine rapidly dries out and is blown away after the anthers dehisce. Therefore, from the point of view of a pollen-collecting bee, pollen from wind-pollinated flowers is best collected soon after it becomes exposed. In grapevine, pollen becomes available immediately after the calyptra is shed, a process also referred to as capfall. We show, for the first time, that honey bees foraging on grapevine actively remove the calyptra from flowers. Using manual cap removal, we estimate that cap removal increases the pollen yield by 70 % compared to collecting pollen from flowers after capfall. The bees selectively foraged on inflorescences with high numbers of loose caps, thus further enhancing their pollen revenue. We discuss the possible benefits of cap removal by honey bees for the development of individual berries and grape bunches of certain varieties.

Analysing food webs in agricultural habitats is essential for the development of natural control strategies. Several molecular tools to investigate trophic interactions on a species-specific level have been developed in recent years and their advantages and limitations have been discussed. With this study we introduce another tool, terminal restriction fragment length polymorphism (tRFLP). Generalist predators found in Australian brassica crops, their prey and abundant parasitoids were chosen as a model system to adapt and evaluate the tRFLP approach. Using general primers and selecting six restriction enzymes, we obtained species-specific tRF patterns for 21 of the most abundant arthropods in brassica crops. We detected up to three prey species in the gut contents of laboratory-fed predators. Detection rates differed among predators, ranging between 28 and 100%. The identification of a species-specific tRF pattern was strongly affected by the presence and concentrations of DNA from other species. In a preliminary field study, prey could be identified from 20% of the collected brown lacewings. The advantage of the tRFLP method is the possibility of identifying multiple species at once. This advantage is counterbalanced by methodological limitations, among which the most critical one is the fact that it will be difficult to maintain specificity in highly diverse ecosystems. However, if species diversity is limited and the target sequence and the primers are chosen to increase detection success, the tRFLP method can be used to study trophic interactions in the field.

Carpenter bees (Xylocopa) display variation in mating strategies. In several subgenera males defend territories that contain resources for females. In other subgenera males defend a small non-resource territory. Here, we investigate the correlation between three morphological traits and mating strategy. We found associations between mating strategy and male eye size, size of the mesosomal gland and sexual colour dimorphism, as well as correlative evolution between the morphological characters. Analysis of the evolutionary pathways shows that resource defence, small glands and monomorphic sexes are ancestral states. Increases in gland size seem to precede or coincide with changes in mating behaviour, but changes towards sexual dimorphism follow changes in mating behaviour. Once a non-resource defence strategy with correlated morphology has evolved there are no reversals to the ancestral states. We discuss the types of selection that may have caused these correlative changes.

Constraints to independent nesting play a key role in the understanding of social evolution in insects, but the source and the magnitude of such constraints are poorly known for many key taxa. In allodapine bees it is known that solitary nesting females have low rates of successful brood rearing and that this drives selection for cooperative nesting. It has been hypothesized that these constraints are due to the presence of enemies-at-the-nest, such as ants, but no direct link has been demonstrated between such enemies and colony failure. We set up an experiment in which solitary founded nests of an Australian allodapine bee, Exoneura nigrescens, were either protected from non-flying predators or left unprotected, and compared the resulting colony survival and brood production rates. We found that protected colonies have much higher rates of survival and that the constraints to independent nesting are extreme, with a mean of less than one offspring per nest at the end of the brood rearing period. This means that cooperative nesting is essential for this species to persist in its habitat.

This paper launches an open access DNA barcoding project “AUSBS” under the Barcoding of Life Datasystems (BOLD). The aims of the project are to help scientists who lack the necessary morphological knowledge to identify known species using molecular markers, to aid native bee specialists with the recognition of species groups that morphologically are difficult to define, and, eventually, to assist with the recognition of new species among known species. Using integrative taxonomy, i.e. morphological comparison to type specimens in Australian museum collections combined with phylogenetic analysis of a fragment of the mitochondrial DNA cytochrome c oxidase subunit I (mtCOI) gene sequences led to the recognition of four new species of Euhesma Michener (Hymenoptera: Colletidae: Euryglossini) collected during intensive surveys in remote Australian conservation areas, which are described. The new species are Euhesma micans, Euhesma lyngouriae, and Euhesma aulaca in a species group associated with Eremophila flowers, and Euhesma albamala in the walkeriana species group.

Amegilla spp. (Hymenoptera: Anthophoridae) have been suggested as potential native Australian alternative to overseas used bumblebees (Bombus spp.) for pollination of tomato in greenhouses. In this study, we investigate the effectiveness of Amegilla chlorocyanea Cockerell as a greenhouse pollinator of tomato, Lycopersicon esculentum Mill. We show that 1) a single buzz by a female increases tomato weight by 11% compared with pollination by using an industrial pollination wand, 2) multiple buzzes increase tomato weight compared with a single buzz, and 3) unlimited flower visits lead to an increase in fruit weight of 21% compared with wand pollination. These results are comparable with those achieved by bumblebee pollination and demonstrate that A. chlorocyanea is a valid alternative to bumblebees for greenhouse tomato pollination in Australia.

Uneven sharing of reproduction (reproductive skew) among members of a cooperative animal society is one of the key features associated with advanced sociality and task specialization. Allocation of reproduction varies greatly among taxa, and reproductive skew models are evolutionary models that aim at explaining this variation. We tested reproductive skew theory using the Australian social allodapine bee Exoneura robusta. Reproductive skew was negatively correlated with relatedness, as predicted by the so-called tug-of-war model and the restraint model. Both models assume that a dominant breeder in a society does not have full control over the allocation of reproduction among group members, in contrast to classical concession models. Overall, the tug-of-war model seems to account better for the evolution of reproductive sharing in E. robusta than the restraint model. However, neither model can be ruled out, and a tug-of-war as well as a restraint model mechanism could apply in parallel in newly founded and overwintered colonies, respectively. This raises the possibility that skew models are not mutually exclusive and points to a more dynamic view on reproductive partitioning among breeders of an animal society. (c) 2005 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Cooperation between individuals can lead to both increased productivity and increased survival of colonies relative to solitary breeding. We investigated how individual survival, survival of the group and estimates of group productivity are related to colony size in the allodapine bee Exoneura nigrescens. Colony survival strongly depended on initial colony size, but such a correlation was not found for survival of individuals from colonies of different initial sizes. Loss of a female from two-female nests resulted in a decrease in the number of immatures reared through, but such nests still maintained a higher reproductive output than solitary nests. Group benefits have been underestimated in previous publications because changes in colony size and size dependent colony survival had not been taken into account. The relatively large group benefits measured in this study have implications for the expected skew.

The possibility of extending brood care via the overlapping presence of relatively short lived adults could generate advantages that may have been among the selective forces at the origin of eusociality. In this paper we provide evidence for extended brood care through sib-rearing in the arid-zone allodapine bee, Exoneurella eremophila. Solitary females of the overwintered generation generally die before all their offspring have become independent. In a relatively high proportion of nests, a newly eclosed female invests in her siblings while producing her own offspring in the maternal nest. The sex ratio of the first offspring produced by the overwintered female is highly female biased, but the overall sex ratio of the brood is unbiased. This finding supports the prediction of Bull's 'insurance by protogyny' model of a female bias in the first-produced offspring as a strategy by the mother to ensure extended brood care.

SUMMARYThere is commercial pressure to permit the introduction of bumble bees to mainland Australia for pollination of tomatoes in greenhouses. Bumble bees do not occur on mainland Australia, and there are indications that the recently introduced Bombus terrestris presents a threat to native ecosystems on Tasmania. In this pilot study, it was investigated whether the native green carpenter bees (Xylocopa (Lestis)) could be used as an alternative to bumble bees for tomato pollination. It is shown that Lestis females will visit and buzz pollinate flowers in a greenhouse and that tomatoes grown from Lestis pollinated flowers are on average heavier and contain more seeds than tomatoes that were not pollinated by Lestis. Therefore, there is potential to use Lestis for tomato pollination once methods for mass rearing the bees have been developed.

The mass provisioning carpenter bees comprise two tribes, the Xylocopini and the Ceratinini. Although social nesting occurs in both tribes, no morphological castes have evolved and females are totipotent, which makes the tribe as a whole highly suitable to test predictions of reproductive skew models. We review current information for the two tribes with respect to reproductive competition and reproductive skew and then investigate whether the observed skew fits with predictions from optimal skew theory. Social nests of Xylocopa species include a non-foraging guard and a foraging egg layer who completely dominates reproduction. Reproductive dominance is settled by aggression, and the probability of winning this fight is influenced by both age and size. In Ceratina species, task allocation is also very clear: one female guards the nest, while the other female(s) forage(s). Although the guard is usually the first to produce an egg, her eggs are frequently replaced by those of the forager, and skew is incomplete. ¶Using comparisons between species and genera the impact of ecological constraints on solitary nesting, relative group productivity and relatedness on reproductive partitioning between dominants and subordinates are investigated in a qualitative way. In support of the optimal skew model, strong constraints on solitary nesting coincided with strong skew. However, the predicted effects of relatedness and group productivity on skew were not found. Furthermore, no support was found for the predictions of the optimal skew model that high skew coincides with frequent aggressive testing and risky task performance by subordinates.

Comparative studies provide one of the most powerful means of assessing the relative roles of selective agents underlying social evolution in insects. Because of the wide variation in social organisation, sex allocation and ecological traits within and between species of allodapine bees, this group provides a wealth of material for such comparative work. Recent studies on Australian allodapine bees are reviewed here and their consequences for understanding social evolution are discussed. Studies to date suggest the following trends: (i) benefits of group living appear to be linked to preventing brood failure rather than to increased brood rearing efficiency; (ii) female-biased sex allocation, when it occurs, is linked to benefits of group living and kinship among nestmates, and is probably mediated via local fitness enhancement; (iii) female-biased sex allocation patterns do not usually coincide with opportunities for sib-rearing and are therefore unlikely to facilitate eusociality; (iv) relatedness within colonies is usually high, but in some species females will nest with unrelated females if kin are not available; and (v) phylogenetic studies suggest that opportunities for sib-rearing, arising from brood development patterns and colony phenology, are plesiomorphic for the exoneurine group, but in at least one phylogenetically distal clade, Exoneura sensu stricto, the evolution of large group size and social complexity coincides with the loss or reduction of opportunities for sib-rearing. Assured fitness return models may be applicable to weakly social allodapine species, but do not predict patterns of eusociality. Instead, Australian studies suggest that the evolution of large group size and marked reproductive skew is linked with the need to defend against enemies at the nest, rather than high levels of relatedness, female biased sex allocation or opportunities to rear siblings.

The allodapine bee Exoneura bicolor constructs linear nests in pithy centres of dead plant material. Brood is reared progressively. During winter, nests usually contain one mated female with large ovaries and several subordinate females with small ovaries. The dominant female pheromonally inhibits ovarian enlargement of subordinate females. During the foraging season, dominant females guard the nest, while subordinate females undertake the more risk prone foraging activities. During winter, virtually no foraging occurs. Therefore, guarding might be the most dangerous activity during winter. In this paper we investigate whether the position of females in the nest during winter is related to dominance. Females did not change relative position frequently and the position of females decreased near monotonically with ovary size, with the dominant female closest to the nest entrance. It is concluded that: (1) dominant females do not move about in the nest to ensure spread of their pheromones among nestmates, or to behaviourally inhibit ovarian enlargement of subordinates; (2) dominant females do not force subordinates to guard the nest. Because the guard is probably the female that is most subject to predation during winter, guarding by the dominant should have some payoffs. Potential benefits are: (a) contamination of incoming air with volatile pheromones; (b) preventing intruders from entering the nest; (c) controlling nestmates leaving and entering the nest. The latter may enable females to control food that is brought back into the nest, and to prevent mating by subordinate females. Our results indicate that social structure within these nests is influenced by the linear structure of the nest burrows.

International audience; The yields of yellow passion fruit are vulnerable to pollinator decline because the crop is strictly self-incompatible. Nectar foraging carpenter bees are the main pollinators of this crop, whereas honeybees and stingless bees take pollen and nectar without pollination, and can be classified as “thieves”. In many cropping areas, the density of effective pollinators is very low and precludes optimal yield. We investigated, over a period of 6 months, whether the provision of unoccupied and occupied carpenter bee nests could lead to (a) an increase in crop visitation by carpenter bees and (b) a decrease in visitation by thieves. We found that introduction of occupied nests can influence visitation by both carpenter bees and thieves in the expected ways, while the sole provision of unoccupied nests did not achieve this. Our study can be regarded as an important step for increasing pollinators’ population in yellow passion fruit orchards using trap-nests as nesting substrate.

In nests of the facultatively social carpenter bee X~~loropa puhrscm.s, both intruders and nestmates destroyed brood during supersedure. However, nestmates and intruders differed with respect to the frequency and the pattern of brood destruction. Intruders destroyed more brood than did nestmates. In addition, intruders appeared to destroy all stages of brood at equal frequencies, whereas nestmates had a preference for opening and thereby destroying newly made cells. Several hypotheses concerning the ultimate reasons for these differences were tested. These differences are not due to either a lack of breeding space, or to an attempt to prevent an imminent loss of dominance. The number of brood cells destroyed by nestmates was not influenced by the degree of relatedness. This indicates that the difference between nestmates and intruders was not based on active kin recognition. The most likely reason why nestmates prefer to open young brood cells is that they can then reallocate the pollen contents of these cells to their own brood. A difference in knowledge about the location of newly made cells may explain the differences in the pattern and the frequency of brood destruction by nestmates and intruders. Furthermore, a superseding nestmate may slightly enhance her average indirect fitness by destroying the brood contents of newly made cells while leaving older brood cells intact.