Fishing for flies : testing the efficacy of "stink stations" for promoting blow flies as pollinators in mango orchards

Pollinator communities are composed of diverse groups of insects, with radically different life histories and resource needs. Blow flies are known to visit a variety of economically important crop plants. Larval blow flies develop by feeding on decaying animals. Some fruit growers are known to place carrion on farms during the flowering season to attract adult blow flies (Calliphoridae). However, the efficacy of these “stink stations” has not been tested. We conducted a series of experiments to determine: 1) if stink stations promote the abundance of blow flies in mango orchards (Mangifera indica L.), 2) if any increases in the abundance of flies acts to promote pollination and fruit set in Australian mango orchards. Farms with stink stations had approximately three times more flies than control farms. However, the increased abundance of blow flies did not result in increased fruit set. Although stink stations increased the abundance of blow flies, we found no evidence that their use improves mango yield. This may be due to pollination saturation by a highly abundant native hover fly, Mesembrius bengalensis (Syrphidae), during our study. We hypothesize that stink stations may only be beneficial in years or regions where other pollinators are less abundant

Floral biology, pollination vectors and breeding system of Zieria granulata (Rutaceae), an endangered shrub endemic to eastern Australia

Context: Understanding the factors that influence viable-seed production is crucial in the conservation of threatened plant species, yet these factors are often poorly understood. Aims: We investigated the reproductive biology of Zieria granulata C.Moore ex Benth., an endangered Australian endemic with a limited distribution, with the intent of improving conservation and restoration outcomes. Methods: Components of floral biology, including floral ontogeny and nectar production, were quantified to determine the pollination syndrome and the likely breeding system. Flower-visitor surveys (using both digital video recordings and human observations), a manipulative wind-pollination experiment and hand-pollination experiments were conducted to investigate pollination vectors and confirm the breeding system. Key results: Z. granulata flowers were small, white, protandrous and produced highly ornamented pollen grains and small quantities of nectar; these characteristics suggest that the species fits the general entomophily syndrome. All floral visitors were arthropod species and of the 72 visitors observed, predominantly from the Dipteran and Hymenopteran families, 18 could be regarded as potential pollinators. Failure of simulated wind gusts (40 km h-1) to transport pollen ≥5 cm indicated that anemophily is unlikely for this species. Autonomous and manipulative selfing did not result in viable seed set, indicating that this is an obligate outcrossing species. However, fruit and viable-seed production was highly variable within and among some other treatments. Pre-dispersal seed predation was recorded at all study sites. Conclusions: Pre-dispersal seed predation was recorded at all study sites and is a likely factor inhibiting viable-seed production. Implications: This knowledge will be used to improve seed yield for collections used for ex situ conservation and restoration programs for the endangered Z. granulata

Insecticide efficacy against Earias species infestation of okra and residue analysis of chlorantraniliprole under field conditions in India

A field study was conducted to compare the efficacy of 10 recommended insecticides against Earias spp. on okra. Three okra plots (3 m × 5 m (15 m2)) were subjected to each of the 10 insecticidal sprays applied twice at an interval of 10 days. On the third, seventh, and tenth day after each spray, percent shoot and fruit infestation and yield were calculated. All insecticides significantly reduced shoot and fruit infestation compared to the control. However, chlorantraniliprole 18.5%SC was the most effective across all time points and resulted in the highest yield. A second field study, to determine the time till the maximum residue limit (MRL—0.3 mg/kg) and the limit of quantification (LOQ—0.01 mg/kg) for both fruit and soil exposed to either the recommended (125 mL/ha) or a double strength dose (250 mL/ha) of chlorantraniliprole 18.5% SC was undertaken. MRL was reached on the same day following both doses. The LOQ was reached on the seventh and tenth day at recommended and a double strength dose, respectively. Chlorantraniliprole 18.5% SC provides effective control. However, Earias spp. resistance has been observed in other crops. Thus, constant monitoring in the field is needed to ensure its effectiveness

Pollinator-flower interactions in gardens during the COVID-19 pandemic lockdown of 2020

During the main COVID-19 global pandemic lockdown period of 2020 an impromptu set of pollination ecologists came together via social media and personal contacts to carry out standardised surveys of the flower visits and plants in gardens. The surveys involved 67 rural, suburban and urban gardens, of various sizes, ranging from 61.18° North in Norway to 37.96° South in Australia, resulting in a data set of 25,174 rows, with each row being a unique interaction record for that date/site/plant species, and comprising almost 47,000 visits to flowers, as well as records of flowers that were not visited by pollinators, for over 1,000 species and varieties belonging to more than 460 genera and 96 plant families. The more than 650 species of flower visitors belong to 12 orders of invertebrates and four of vertebrates. In this first publication from the project, we present a brief description of the data and make it freely available for any researchers to use in the future, the only restriction being that they cite this paper in the first instance. The data generated from these global surveys will provide scientific evidence to help us understand the role that private gardens (in urban, rural and suburban areas) can play in conserving insect pollinators and identify management actions to enhance their potential

Can the pollination biology and floral ontogeny of the threatened Acacia carneorum explain its lack of reproductive success?

Many Acacia species in arid areas of eastern Australia have been severely impacted by grazing, habitat degradation and fragmentation. These factors have been at the core of proposed explanations for the reproductive failure and numerical decline of Acacia carneorum and other threatened acacias. Paradoxically, the sympatric Acacia ligulata is thriving and highly fecund. Although these species have superficially similar floral displays, differences in sexual reproductive success may reflect interactions between flower and inflorescence ontogeny and pollinator assemblages. We compared the floral biology and flower visitor assemblages of A. carneorum and A. ligulata at four sites per species. Both species displayed similar floral ontogeny and synchronicity of display, with inflorescences simultaneously hermaphroditic for 4–5 days. However, A. ligulata displayed a higher density of flowers than A. carneorum and, while both species received a range of flower visitors, A. ligulata was visited by relatively few species and was serviced primarily by the non-native honeybee Apis mellifera, which typically made many within-plant movements during foraging bouts. In contrast, A. carneorum was visited by a diverse suite of native insects that carried little pollen and made fewer within plant movements. On average, Apis mellifera carried 98.4 % A. ligulata pollen, whereas the native insect visitors of A. carneorum carried only 45 % A. carneorum pollen. Differing floral ontogeny or lack of native pollinators does not explain the reproductive failure of A. carneorum. The success of A. ligulata may reflect pollination services provided by A. mellifera and interactions with plant mating systems

Do mass flowering agricultural species affect the pollination of Australian native plants through localised depletion of pollinators or pollinator spillover effects?

Australian agricultural landscapes are dominated by northern-hemisphere mass flowering species, with the potential to disrupt pollination of adjacent co-flowering plants. In northern-hemisphere systems, mass flowering plants can act as ‘pollinator magnets’. Magnets can reduce the pollination success of adjacent co-flowering neighbours by drawing pollinators from these plants. However, magnets can also produce pollination ‘spillover-effects’ through increased pollinator movements to adjacent co-flowering taxa, potentially either increasing pollination or impacting it through transfer of mixed-species pollen. The impact of agricultural species on co-flowering plants in Australia is unknown. Native Australian plants evolved with unique pollinators and yet agricultural pollination is dominated by the exotic honeybee Apis mellifera. We tested how distance (to 250 m) from each of two populations of Lavender (Lavandula spp.) (2 years), Nectarines (Prunus persica var. nucipersica or var. nectarina) (1 year) and the pasture weed Paterson's Curse (Echium plantagineum) (2 years) affected pollinator diversity and abundance within experimental arrays of native and northern-hemisphere plants. For Paterson's Curse, we tested whether visitation varied when honeybee abundance was experimentally increased. As expected, we found magnets attracted significantly more honeybee visits in all possible comparisons across combinations of species, sites and years. However, contrary to expectation, in 10 of 18 comparisons, co-flowering species supported a slightly higher diversity of pollinators than magnets, with honeybees comprising a significantly lower proportion of flower visitors in 14 comparisons. The exceptions, which included populations of all three magnet species, were cases where honeybees were the only visitor (6 comparisons) or the magnet and co-flowering species were each visited by a single but different pollinator (2 compariosns). Most strikingly, our data provided no evidence of pollinator spillover. More than 95% of all pollinators on co-flowering species carried only their pollen and overall pollinator abundance didn't vary significantly with distance from magnets at any site or time. Honeybee abundance did not vary significantly with distance from magnets. For Paterson's Curse, the addition of managed hives increased honeybee abundance on co-flowering species in two of eight cases, but pollinator abundance didn't vary with distance from the magnet. Overall, we found few direct effects of mass flowering agricultural species on the pollination of either Australian native or exotic neighbours. The lack of spillover-effects may largely reflect the unusually high species fidelity of foraging A. mellifera. However, the numerical dominance of honeybees within Australian agricultural systems may impact pollination at the regional level

Reproductive biology of rainforest Rutaceae : floral biology, breeding systems and pollination vectors of Acronychia oblongifolia and Sarcomelicope simplicifolia subsp. simplicifolia

The conservation of plant species requires an understanding of the factors that affect viable seed production, but often these factors are poorly understood. We investigated the reproductive biology of two Australian endemic rainforest species, Acronychia oblongifolia (A.Cunn. ex Hook.) Endl. ex Heynh and Sarcomelicope simplicifolia (Endl.) T.G.Hartley subsp. simplicifolia, with the intent of improving conservation and restoration outcomes. The floral biology of these species was quantified to provide baseline data and insights into their pollination syndrome. Flower visitor surveys (using both digital recordings and human observations), a manipulative wind pollination experiment, and hand-pollination experiments were carried out to investigate pollination vectors and determine the breeding system. Acronychia oblongifolia and Sarcomelicope simplicifolia subsp. simplicifolia were both found to best fit the general entomophily pollination syndrome. All floral visitors were arthropod species (Acronychia oblongifolia: 31; Sarcomelicope simplicifolia subsp. simplicifolia: 47) and fewer than 30% of the floral visitors identified, predominantly Diptera, Hymenoptera and Coleoptera, were regarded as potential pollinators. Failure of simulated wind gusts (40 km h-1) to transport pollen 50 cm indicated anemophily is unlikely for these species. Autonomous and manipulative selfing treatments produced few (Acronychia oblongifolia: <3%) or no (Sarcomelicope simplicifolia subsp. simplicifolia) viable seed, indicating these are predominantly outcrossing species, although fruit and viable seed production were highly variable within and among all other treatments (open to natural pollinators, pollinator exclusion, pollinator exclusion and manipulative outcross, and pollinator exclusion and manipulative selfing). Pre-dispersal seed predation was recorded for both species, at several study sites. Pre-dispersal seed predation and increased distances between compatible individuals caused by habitat fragmentation, are two factors limiting the production of viable seeds for both species

Do introduced honeybees affect seed set and seed quality in a plant adapted for bird pollination?

Aims: Worldwide, evidence suggests that exotic pollinators can disrupt plant mating patterns. However, few studies have determined if pollination by the honeybee Apis mellifera (the world’s most widely introduced pollinator) reduces offspring quality when compared with pollination by native birds. The Australian Proteaceae provides an excellent opportunity to test the impact of honeybees in pollination systems that are adapted to birds and non-flying mammals. Methods: We compared the frequency of flower visitation and foraging behaviour of birds and insects within seven populations of Banksia ericifolia. Banksia ericifolia is hermaphroditic and has large nectar-rich, orange inflorescences typical of bird and mammal pollinated species. For a subset of the study populations, we compared the quality of seed produced via an exclusion treatment (that only allowed invertebrates to access flowers) with an open-pollination treatment (potentially visited by mammals, birds and invertebrates), by measuring seed weight, germination rates (T50), percent germination, seedling height after 14 days since the emergence of the cotyledon and time to emergence of the cotyledon. Important Findings: Apis mellifera was the only apparent insect pollinator and the most frequent flower visitor, while the open treatment inflorescences were also frequently visited by avian pollinators, primarily honeyeater species. The foraging behaviour of honeybees and honeyeaters showed striking differences that potentially affect patterns of pollen transfer. Honeybees made significantly greater proportions of within cf. among plant movements and only 30% (n = 48) of honeybees foraged for pollen (nectar foragers carried no pollen) whilst all birds were observed to contact both stigmas and anthers when foraging for nectar. Despite these fundamental differences in behaviour, there was little effect of treatment on seed set or quality. Our data show that while honeybees appear to alter patterns of pollen transfer within B. ericifolia populations, they do not impact reproductive rates or performance of early life-stages

Research and conservation initiatives for the vulnerable purple-wood wattle : a model for plant species conservation in Australia?

Research on rare and threatened plants is a major focus of conservation biology. We want to know why species are rare or declining, how best to arrest that decline and what is lost when species become locally extinct. Occasionally, understanding decline is straightforward - e.g. if the species is restricted to fertile soils that are desirable for cultivation. However, managing declining populations is more complex and requires knowledge of genetic diversity and interspecific interactions

Restoration of native wildflower patches in agronomic settings for diverse and healthy pollinator populations

Globally, about 88% of angiosperms rely on animal pollinators to set seed and reproduce (Ollerton et al. 2011). Pollination is therefore a critical ecosystem service, underpinning plant reproductive success and, for crop species, associated yields. Many horticultural crops, including the economically and locally important apple industries, are reliant on insect pollination (Rogers et al. 2014). Yet while there is a wide range of native pollinating insects (including wasps, bees, flies, butterflies, hoverflies and ants; Figure 1) most agronomic systems focus heavily on a single pollinator – the European Honeybee (Apis mellifera). Honeybee hives are typically brought onto farms for specific crop flowering periods, a practice that has not only high financial costs to farmers, but a high risk associated with dependence on a single pollinator, especially in the context of disease threats (notably Varroa Mite) to this species. Moreover, many fruit crops get added benefits from pollination by wild pollinators, even when Honeybees are abundant (Garibaldi et al. 2013). Hence it is vital to support resident pollinator populations in cropping landscapes