Provisioning Australian Seed Carrot Agroecosystems with Non-Floral Habitat Provides Oviposition Sites for Crop-Pollinating Diptera
The addition of floral resources is a common intervention to support the adult life stages of key crop pollinators. Fly (Diptera) crop pollinators, however, typically do not require floral resources in their immature life stages and are likely not supported by this management intervention. Here, we deployed portable pools filled with habitat (decaying plant materials, soil, water) in seed carrot agroecosystems with the intention of providing reproduction sites for beneficial syrphid (tribe Eristalini) fly pollinators. Within 12 to 21 days after the pools were deployed, we found that the habitat pools supported the oviposition and larval development of two species of eristaline syrphid flies, Eristalis tenax (Linnaeus, 1758) and Eristalinus punctulatus (Macquart, 1847). Each habitat pool contained an average (±S.E.) of 547 ± 117 eristaline fly eggs and 50 ± 17 eristaline fly larvae. Additionally, we found significantly more eggs were laid on decaying plant stems and carrot roots compared to other locations within the pool habitat (e.g., on decaying carrot umbels, leaves, etc.). These results suggest that deploying habitat pools in agroecosystems can be a successful management intervention that rapidly facilitates fly pollinator reproduction. This method can be used to support future studies to determine if the addition of habitat resources on intensively cultivated farms increases flower visitation and crop pollination success by flies.
Fly (Diptera) pollination efficiency and reproductive needs within crop agroecosystems - Dataset
This dataset consists of eight tabs (the first four relating to Chapter 2 and the remaining four relating to Chapters 3, 4, 5, and 6 of my thesis). All data related to this thesis was collected online from the Web of Science and Scopus search engines (Chapter 2), the CropPol and Rader et al. 2020 public databases, and in the field from Griffith, New South Wales, Australia (Chapters 3, 4, and 5), from the East-North Coast of New South Wales, Australia (Chapter 6), and from Northern Tasmania, Australia (Chapter 6). Each tab has an excel spreadsheet with data from each thesis research chapter, and the content of each tab is explained below: Chapter 2.1: A review of the life history needs of the larval and adult stages of crop flower-visiting flies (Diptera). This dataset consists of family, genus, and species names extracted from public pollination databases ('CropPol' or 'Rader et al. 2020'), the total number of searches the species name received from Scopus and/or WOS (Web of Science), whether the information for the diet and habitat needs were found ('Accessible' or 'Inaccessible'), the total number of larval and adult feeding guilds the fly may utilize ('Unknown', 'One', 'Two', 'Three', 'Four', 'Five', or 'Six'), whether the fly utilizes the same feeding guilds in both active developmental stages of life ('Unknown', 'Different', or 'Same'), and finally the dataset in which the species name was extracted from ('CropPol' or 'Rader et al. 2020'). Chapter 2.2: A review of the life history needs of the larval and adult stages of crop flower-visiting flies (Diptera). This dataset consists of adult fly life history information extracted from reviewed articles, such as the feeding mechanism (e.g., chewing decaying animal flesh, sucking blood, etc.), habitat, and feeding substrate of specific crop flower-visiting fly species. The quality of this extracted information is placed in two categories ('Validated in experiment', or 'Inferred (by authors)'). Chapter 2.3: A review of the life history needs of the larval and adult stages of crop flower-visiting flies (Diptera). This dataset consists of the larval fly life history information extracted from reviewed articles, including the feeding mechanism (e.g., chewing decaying animal flesh, sucking blood, etc.), habitat, and feeding substrate of specific crop flower-visiting fly species. The quality of this extracted information is placed in four categories ('Validated in experiment', 'Inferred (by authors)', '(Validated by) Expert', and 'Unable to access'). Chapter 2.4: A review of the life history needs of the larval and adult stages of crop flower-visiting flies (Diptera). This dataset consists of the data on the biogeographic host range of the species and was extracted from species catalogues, manuals, and websites (‘References’) managed by experts in the field of Dipterology. One species may occupy more than one biogeographical region. Chapter 3: Floral visitation surveys of insect visitors of hybrid seed carrot (Daucus carota subsp. sativus) crop plants. Surveys were conducted up to three times a week during full bloom (22 November to 5 December 2021) at six sites throughout the day (05:00 to 17:00). Surveys were conducted along two, 10 m transects: one along the edge of the carrot field and an additional walk in the middle (> 30 m into the field). All transects were conducted walking slowly (1 m per minute when possible) between two rows of carrot plants (either ‘Male’ and ‘Female’ or ‘Monoecious’ and ‘Monecious’). The temperature and relative humidity was recorded using Kestrel® Drop D2 data loggers permanently deployed in a shaded location within, or nearby, all study sites. All insects were identified to the lowest taxonomic level using dichotomous keys. Chapter 4: Deploying habitat to support the immature life stages of eristaline flies (Syrphidae) in hybrid seed carrot crop agroecosystems. In a paired experimental design, two habitat pools filled with substrates (‘carrot’ and ‘soil’) intended to attract eristaline flies were deployed at 7 sites. The pools were placed between 15 November to 24 November 2021 and left to decay for 12 to 21 days. Surveys of the immature life stages (‘eggs’ and/or ‘larvae’) were identified and counted within the pools. The state of the larvae (‘first instar’, ‘second instar’, ‘third instar’, or ‘dead’) as well as the location where batches of eggs were laid within the deployed habitat were determined. Chapter 5: Effectiveness of fly and bee pollinators at pollinating hybrid carrot plants grown for seed. This dataset consists of stigmas collected after a single visit by one pollinator species. The first column is date the replicate was collected, the second column is the pollinator species, the third column is the duration of time in seconds the pollinator spent visiting the replicate, the fourth column is the number of stigmas mounted on the slide, the fifth column is the number of pollinated stigmas (at least one pollen grain touching the stigma), and the sixth column is the total number of pollen grains touching the carrot stigmas. Chapter 6: Efficiency of fly and bee pollinators at pollinating blackberry (Rubus fruticosus) and raspberry (Rubus ideaus) crop plants. This dataset consists of berries harvested after single visitation (one visit to a flower), unlimited visitation (allowed access to flowers in a small cage setting), and open pollination (scale of a farm polytunnel) treatments under field conditions. The first column is the unique pollinator ID, the second column is the pollinator species, the third column is the type of trial (‘Cage’ or ‘Field’), the fourth column is the weight of the harvested fruits, the fifth column is the number of drupelets per fruit, the sixth column is type of defect found in the fruit (’None’, ‘Progressive’, or ‘ Critical’) as per industry standards, and the seventh column explains the type of defect seen in the fruit (if any).
Within-Colony Transmission of Microsporidian and Trypanosomatid Parasites in Honey Bee and Bumble Bee Colonies
Parasites are commonly cited as one of the causes of population declines for both managed and wild bees. Epidemiological models sometimes assume that increasing the proportion of infected individuals in a group should increase transmission. However, social insects exhibit behaviors and traits which can dampen the link between parasite pressure and disease spread. Understanding patterns of parasite transmission within colonies of social bees has important implications for how to control diseases within those colonies, and potentially the broader pollinator community. We used bumble bees (Bombus impatiens Cresson) (Hymenoptera: Apidae) and western honey bees (Apis mellifera L.) (Hymenoptera: Apidae) infected with the gut parasites Crithidia bombi (Lipa & Triggiani) (Trypanosomatida: Trypanosomatidae) and Nosema ceranae (Fries et al.) (Dissociodihaplophasida: Nosematidae), respectively, to understand how the initial proportion of infected individuals impacts within-colony spread and intensity of infection of the parasites. In bumble bees, we found that higher initial parasite prevalence increased both the final prevalence and intensity of infection of C. bombi. In honey bees, higher initial prevalence increased the intensity of infection in individual bees, but not the final prevalence of N. ceranae. Measures that reduce the probability of workers bringing parasites back to the nest may have implications for how to control transmission and/or severity of infection and disease outbreaks, which could also have important consequences for controlling disease spread back into the broader bee community.
The Complete Field Guide to the Dragonflies of Australia (Second Edition)
A popular field guide among amateur and expert naturalists alike, the first edition of ‘The Complete Field Guide to the Dragonflies of Australia’ was reprinted three times without substantial revisions to dragonfly systematics and geographical distributions. Fourteen years later, Theischinger and Hawking are back with a revised second edition of their comprehensive field guide, and they do not disappoint.
The purpose and layout of the second edition is similar to the first. There are three distinct sections of the book: an introduction, a species guide, and information on identification and resources. The introduction provides an overview of the unique nature of Australian endemic odonates, including the life cycle, ecology, habitat and conservation of species. This brief section is helpful to the hobbyist but is a review for the entomologist.
Observations of nectarivorous birds and potential biological control agents in berry orchards
We observed the brown honeyeater, Lichmera indistincta, visiting blueberry orchards in eastern Australia. L. indistincta is considered to be a nectarivorous bird, feeding almost entirely on nectar. However, we report observations of this species as both a nectarivore and insectivore in blue-berry crops and as an insectivore in raspberry crops. Brown honeyeaters may be acting as biological control agents when feeding on leaf-roller caterpillars (Lepidoptera: Tortricidae) in blueberry orchards and on brown blow-flies (Calliphora stygia) in raspberry orchards. Although most blueberry growing regions use managed honey bees as the main pollinator, more studies on the complex tritrophic interactions occurring in these crops are needed to better understand the costs and benefits of different farm management practices upon alternative pollinators.
The golden native drone fly (Eristalinus punctulatus) is an effective hybrid carrot pollinator that lives within Australian crop agroecosystems
1. Native insect flower visitors can be important contributors to crop pollination, yet little is known of their pollination abilities and the resources (habitat) they need to be supported within crop agroecosystems.
2. Here, we compared the abundance and pollination abilities of the golden drone fly (Eristalinus punctulatus) to the European honey bee (Apis mellifera) in hybrid carrot crop fields known to produce variable seed yields in regional New South Wales, Australia. We further observed the egg-laying behaviours of female golden drone flies at a commercial berry orchard to provide insight into the habitat needs of this species.
3. In hybrid carrot crop fields, golden drone flies were far less abundant flower visitors than European honey bees" however, these flies deposited more carrot pollen grains on average (8.21±3.04SE) onto carrot flowers than European honey bees (3.45±1.06SE). Both insects also deposited pollen onto a similar number of carrot flowers (pollinated) per visit (about 2 out of 18).
4. Golden drone flies were observed laying eggs within masses of discarded red raspberry plant roots and soil (root balls) at a commercial berry orchard. The natural habitat utilised by these flies, as well as their egg-laying behaviours, were described for the first time.
5. Our results indicate that golden drone flies are effective pollinators of hybrid carrot crop plants. The habitat that these flies utilised to lay eggs (discarded plants and water) is cheap and commonly found in crop agroecosystems. Therefore, we recommend placing this low-cost habitat within, or nearby, crop fields as a potential management practice to support the lifecycle needs of golden drone flies and other non-bee pollinators.
Crop-pollinating Diptera have diverse diets and habitat needs in both larval and adult stages
Insects are important pollinators of global food crops and wild plants. The adult and larval diet and habitat needs are well known for many bee taxa, but poorly understood for other pollinating taxa. Non-bee pollinators often feed on different substrates in their larval and adult life stages, and this diet and habitat diversity has important implications for their conservation and management. We reviewed the global literature on crop pollinating Diptera (the true flies) to identify both larval and adult fly diet and habitat needs. We then assembled the published larval and adult diets and habitat needs of beneficial fly pollinators found globally into a freely accessible database. Of the 405 fly species known to visit global food crops, we found relevant published evidence regarding larval and adult diet and habitat information for 254 species, which inhabited all eight global biogeographic regions. We found the larvae of these species lived in 35 different natural habitats and belong to 10 different feeding guilds. Additionally, differences between adult Diptera sexes also impacted diet needs; females from 14 species across five families fed on protein sources other than pollen to start the reproductive process of oogenesis (egg development) while males of the same species fed exclusively on pollen and nectar. While all adult species fed at least partially on floral nectar and/or pollen, only five species were recorded feeding on pollen and no fly larvae fed on nectar. Of the 242 species of larvae with established diet information, 33% were predators (n = 79) and 30% were detritivores (n = 73). Detritivores were the most generalist taxa and utilized 17 different habitats and 12 different feeding substrates. Of all fly taxa, only 2% belonged to the same feeding guild in both active life stages. Our results show that many floral management schemes may be insufficient to support pollinating Diptera. Pollinator conservation strategies in agroecosystems should consider other non-floral resources, such as wet organic materials and dung, as habitats for beneficial fly larvae.
Crop-pollinating Diptera have diverse diets and habitat needs in both larval and adult stages
Insects are important pollinators of global food crops and wild plants. The adult and larval diet and habitat needs are well known for many bee taxa, but poorly understood for other pollinating taxa. Non-bee pollinators often feed on different substrates in their larval and adult life stages, and this diet and habitat diversity has important implications for their conservation and management. We reviewed the global literature on crop pollinating Diptera (the true flies) to identify both larval and adult fly diet and habitat needs. We then assembled the published larval and adult diets and habitat needs of beneficial fly pollinators found globally into a freely accessible database. Of the 405 fly species known to visit global food crops, we found relevant published evidence regarding larval and adult diet and habitat information for 254 species, which inhabited all eight global biogeographic regions. We found the larvae of these species lived in 35 different natural habitats and belong to 10 different feeding guilds. Additionally, differences between adult Diptera sexes also impacted diet needs; females from 14 species across five families fed on protein sources other than pollen to start the reproductive process of oogenesis (egg development) while males of the same species fed exclusively on pollen and nectar. While all adult species fed at least partially on floral nectar and/or pollen, only five species were recorded feeding on pollen and no fly larvae fed on nectar. Of the 242 species of larvae with established diet information, 33% were predators (n = 79) and 30% were detritivores (n = 73). Detritivores were the most generalist taxa and utilized 17 different habitats and 12 different feeding substrates. Of all fly taxa, only 2% belonged to the same feeding guild in both active life stages. Our results show that many floral management schemes may be insufficient to support pollinating Diptera. Pollinator conservation strategies in agroecosystems should consider other non-floral resources, such as wet organic materials and dung, as habitats for beneficial fly larvae.
Insects and spiders on the web: Monitoring and mitigating online exploitation of species and services
Exploitation of insects and spiders through commercialization represents a serious threat to rare species and to common species that provide valuable ecological services. The speed, scope, and anonymity, of online commerce places full monitoring and managing of exploitation beyond the resources available to regulatory agencies. To assess the level of online commerce of insect and spider species and services and to test the feasibility of focused searches by student-specialists to generate "leads" for regulatory agencies to pursue, a group of entomology students lead by entomologists and wildlife biologists performed a directed search for sales of insect and spider species listed on CITES Appendices, the IUCN Red List, and the U.S. Endangered Species List, and species that provide services. Focused searches by student-specialists proved effective, locating sales of 79 listed species across all lists. The proportion of listed species discovered for sale varied from 2% to 55% across protected lists and the sale prices of species varied from 2 to 3850 USD. The number of listed species for sale also varied across platforms with less than 6 found on either Amazon or Alibaba and more than 30 found on Etsy and Ebay. In contrast to the listed species, numbers of insects and spiders sold to provide services can range in the billions of individuals and total sales can range in the millions USD. While all species for this purpose do provide a service, they each present unique risks to other species in their genera, guild, and to the larger ecological community, in some cases threatening ecological functions. To effectively monitor the impact of invertebrate service species, we propose incorporating these "livestock" into the existing regulatory framework used for vertebrates.