Reading tea leaves worldwide: Decoupled drivers of initial litter decomposition mass-loss rate and stabilization.

The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.

The final frontier: ecological and evolutionary dynamics of a global parasite invasion.

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.

Mounting evidence that managed and introduced bees have negative impacts on wild bees: an updated review.

Worldwide, the use of managed bees for crop pollination and honey production has increased dramatically. Concerns about the pressures of these increases on native ecosystems has resulted in a recent expansion in the literature on this subject. To collate and update current knowledge, we performed a systematic review of the literature on the effects of managed and introduced bees on native ecosystems, focusing on the effects on wild bees. To enable comparison over time, we used the same search terms and focused on the same impacts as earlier reviews. This review covers: (a) interference and resource competition between introduced or managed bees and native bees; (b) effects of introduced or managed bees on pollination of native plants and weeds; and (c) transmission and infectivity of pathogens; and classifies effects into positive, negative, or neutral. Compared to a 2017 review, we found that the number of papers on this issue has increased by 47%. The highest increase was seen in papers on pathogen spill-over, but in the last five years considerable additional information about competition between managed and wild bees has also become available. Records of negative effects have increased from 53% of papers reporting negative effects in 2017 to 66% at present. The majority of these studies investigated effects on visitation and foraging behaviour. While only a few studies experimentally assessed impacts on wild bee reproductive output, 78% of these demonstrated negative effects. Plant composition and pollination was negatively affected in 7% of studies, and 79% of studies on pathogens reported potential negative effects of managed or introduced bees on wild bees. Taken together, the evidence increasingly suggests that managed and introduced bees negatively affect wild bees, and this knowledge should inform actions to prevent further harm to native ecosystems.

Continental risk assessment for understudied taxa post-catastrophic wildfire indicates severe impacts on the Australian bee fauna.

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.

How protection of honey bees can help and hinder bee conservation.

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.

Current carbon prices do not stack up to much land use change, despite bundled ecosystem service co-benefits.

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.

Nutritional benefit of fungal spores for honey bee workers.

The collection of fungal spores by honey bees, Apis mellifera, can be classified as active or passive, the latter when spores are associated with pollen, nectar or honey dew. While low quality and shortage of pollen have been raised as hypotheses for fungal spore collection, the nutritional value of fungal spores for honey bees is poorly understood. Here we investigated the effect of consumption of fungal spores on survival, ovarian activation and the development of the hypopharyngeal glands (HPGs) in honey bee workers. Two pollen diets (Eucalyptus sp. pollen and a multifloral pollen) supplemented or not with spores of Botrytis cinerea, Cladosporium sp. or Colletotrichum acutatum were used. Consumption of diets that contained fungal spores increased the longevity of honey bee workers but had no significant effect on the development of their HPGs and ovaries. This demonstrates that fungal spores may have nutritional value for honey bees and that the consumption of fungal spores may compensate for nutritional imbalances of poor-quality pollen diets.

The genus Amegilla (Hymenoptera, Apidae, Anthophorini) in Australia: a revision of the subgenus Asaropoda.

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.

A method to generate multilocus barcodes of pinned insect specimens using MiSeq.

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 <500 bp, which then have to be overlapped using bioinformatics to achieve longer sequence lengths. This increases the risk of generating chimeric sequences or leads to the formation of incomplete loci. Here, we propose a modified nested amplicon sequencing method for targeting multiple loci from pinned insect specimens using the MiSeq Illumina platform. The modification exists in using a three-step nested PCR approach targeting near full-length loci in the initial PCR and subsequently amplifying short fragments of between 300 and 350 bp for high-throughput sequencing using Illumina chemistry. Using this method, we generated 407 sequences of three loci from 86% of all the specimens sequenced. Out of 103 pinned bee specimens of replicated species, 71% passed the 95% sequence similarity threshold between species replicates. This method worked best for pinned specimens aged between 0 and 5 years, with a limit of 10 years for pinned and 14 years for ethanol-preserved specimens. Hence, our method overcomes some of the challenges of amplicon sequencing using short read next generation sequencing and improves the possibility of creating high-quality multilocus barcodes from insect collections.

The effects of temperature on the development, fecundity and mortality of Eretmocerus warrae: is Eretmocerus warrae better adapted to high temperatures than Encarsia formosa?

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.

De novo assembly of honey bee RNA viral genomes by tapping into the innate insect antiviral response pathway.

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.

Twenty six new species of Leioproctus (Colletellus): Australian Neopasiphaeinae, all but one with two submarginal cells (Hymenoptera, Colletidae, Leioproctus).

Twenty six new species of Australian Leioproctus (subgenusColletellus) (Hymenoptera, Colletidae) are described: aberrans Leijs, sp. n., alatus Leijs, sp. n., albipilosus Leijs, sp. n., albiscopis Leijs, sp. n., aliceafontanus Leijs, sp. n., altispinosus Leijs, sp. n., aratus Leijs, sp. n., auricorneus Leijs, sp. n., bidentatus Leijs, sp. n., centralis Leijs, sp. n., ciliatus Leijs, sp. n., claviger Leijs, sp. n., consobrinus Leijs, sp. n., constrictus Leijs, sp. n., laciniosus Leijs, sp. n., longivultu Leijs, sp. n., lucidus Leijs, sp. n., nitidifuscus Leijs, sp. n., pectinatus Leijs, sp. n., pilotapilus Leijs, sp. n., quadripinnatus Leijs, sp. n., rubicundus Leijs, sp. n., rubricinctus Leijs, sp. n., similis Leijs, sp. n., splendens Leijs, sp. n., submetallicus Leijs, sp. n. High resolution images of diagnostic characters for all type specimens are included. Identification keys are provided.

The genus Amegilla (Hymenoptera, Apidae, Anthophorini) in Australia: A revision of the subgenera Notomegilla and Zonamegilla.

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.

New species of Goniocolletes and Trichocolletes (Hymenoptera, Colletidae) from southern Australia.

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

DNA barcoding of euryglossine bees and the description of new species of Euhesma Michener (Hymenoptera, Colletidae, Euryglossinae).

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.

Evolution of blind beetles in isolated aquifers: a test of alternative modes of speciation.

Evidence is growing that not only allopatric but also sympatric speciation can be important in the evolution of species. Sympatric speciation has most convincingly been demonstrated in laboratory experiments with bacteria, but field-based evidence is limited to a few cases. The recently discovered plethora of subterranean diving beetle species in isolated aquifers in the arid interior of Australia offers a unique opportunity to evaluate alternative modes of speciation. This naturally replicated evolutionary experiment started 10-5 million years ago, when climate change forced the surface species to occupy geographically isolated subterranean aquifers. Using phylogenetic analysis, we determine the frequency of aquifers containing closely related sister species. By comparing observed frequencies with predictions from different statistical models, we show that it is very unlikely that the high number of sympatrically occurring sister species can be explained by a combination of allopatric evolution and repeated colonisations alone. Thus, diversification has occurred within the aquifers and likely involved sympatric, parapatric and/or microallopatric speciation.

Chemical and sensory comparison of tomatoes pollinated by bees and by a pollination wand.

Tomato flowers (Solanum lycopersicum L.) in greenhouses require assisted pollination. Compared with pollination using a vibration wand, pollination by buzz pollinating bees results in improved seed set and consequently, higher fruit weight. We investigated whether there are further chemical and sensory differences between bee- and wand-pollinated cherry tomatoes, Solanum lycopersicum variety Conchita. The pollination method did not result in significant differences in concentration of soluble solids and titratable acidity. However, the concentration of soluble solids was significantly positively correlated with seed number. We suggest that an increase in the amount of soluble solids in the locular area, due to increased seed numbers, is counteracted by the effects of seed numbers on the growth of the walls, which occurs through cell elongation. In the sensory part of this study, a large, untrained panel significantly preferred bee-pollinated over wand-pollinated tomatoes and classified bee-pollinated tomatoes as having more depth of flavor than wand-pollinated tomatoes. Thus, bee-pollinated tomatoes taste better than wand-pollinated tomatoes, and it is likely that the sensory differences between the two groups of tomatoes are mediated through effects of pollination treatment on seed numbers. Future chemical and sensory studies of fresh tomatoes should take into account the effects of seed numbers and their possible effect on the distribution of chemical compounds within tomatoes.

Evolution of sociality by natural selection on variances in reproductive fitness: evidence from a social bee.

BACKGROUND: The Central Limit Theorem (CLT) is a statistical principle that states that as the number of repeated samples from any population increase, the variance among sample means will decrease and means will become more normally distributed. It has been conjectured that the CLT has the potential to provide benefits for group living in some animals via greater predictability in food acquisition, if the number of foraging bouts increases with group size. The potential existence of benefits for group living derived from a purely statistical principle is highly intriguing and it has implications for the origins of sociality. RESULTS: Here we show that in a social allodapine bee the relationship between cumulative food acquisition (measured as total brood weight) and colony size accords with the CLT. We show that deviations from expected food income decrease with group size, and that brood weights become more normally distributed both over time and with increasing colony size, as predicted by the CLT. Larger colonies are better able to match egg production to expected food intake, and better able to avoid costs associated with producing more brood than can be reared while reducing the risk of under-exploiting the food resources that may be available. CONCLUSION: These benefits to group living derive from a purely statistical principle, rather than from ecological, ergonomic or genetic factors, and could apply to a wide variety of species. This in turn suggests that the CLT may provide benefits at the early evolutionary stages of sociality and that evolution of group size could result from selection on variances in reproductive fitness. In addition, they may help explain why sociality has evolved in some groups and not others.

Increased tomato yield through pollination by native Australian Amegilla chlorocyanea (Hymenoptera: Anthophoridae).

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.

Tug-of-war over reproduction in a social bee.

One of the main transitions in evolution is the shift from solitary organisms to societies with reproductive division of labour. Understanding social evolution requires us to determine how ecological, social and genetic factors jointly influence group stability and partitioning of reproduction between group members. Here we test the role of the three key factors predicted to influence social evolution by experimentally manipulating them in a social allodapine bee. We show that increased relatedness between nestmates results in more even reproduction among group members and a greater productivity per individual. By contrast, the degree of reproductive skew is not influenced by the opportunity for solitary breeding or by the potential benefits of cooperation. Relatedness also has a positive effect on group stability and overall productivity. These findings are in line with predictions of the tug-of-war models, in which the degree of reproductive division of labour is determined primarily by selfish competition between group members. The alternative view, where the degree of reproductive skew is the outcome of a social contract between potential breeders, was not supported by the data.