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

Abstract

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.

The golden native drone fly (Eristalinus punctulatus) is an effective hybrid carrot pollinator that lives within Australian crop agroecosystems

“…Further, A. mellifera bees were typically seen in high numbers visiting umbels within fields but were more abundant visitors of male fertile umbels compared to male sterile umbels. This finding concurs with other studies that suggest that A. mellifera honey bees are generally inefficient pollinators of hybrid carrots as: (1) honey bees find hybrid male fertile carrot flowers unattractive and thus visit them less frequently than hybrid male sterile flowers (Broussard et al, 2017;Delaplane & Mayer, 2000;Gracie, 2011;Mas et al, 2018), and (2) honey bees rarely move pollen between hybrid parent lines, choosing to instead forage along parent lines (Erickson et al, 1979;Gaffney, 2011;Gaffney et al, 2011Gaffney et al, , 2019Spurr, 2003) (Finch et al, 2023;Pain, 2021), and has been demonstrated…”

“…The habitat in which we observed E. punctulatus fly oviposition can likely be recreated in other crop agroecosystems to support and encourage beneficial eristaline syrphid fly development. Deployment of resources, such as placing manure or carrion near flowering plants to attract pollinators, is common in Australian mango cropping systems (Finch et al., 2023; Pain, 2021), and has been demonstrated to benefit urban environments (Cusser et al., 2021). To support E. punctulatus oviposition, we recommend placing discarded plant material near fields before, or in between, periods of crop bloom to create a habitat for the immature stages of E. punctulatus to develop.…”

“…As discarded plant materials are common in agroecosystems, this habitat intervention will be low cost to growers. The deployment of non‐floral resources such as decaying plant materials to benefit fly pollinators (see Finch et al., 2023 for another example) should be exercised with caution, however, as these substrates could also support the development of pest species like stable flies, Stomoxys calcitrans (Linnaeus, 1758), depending on the geographical location of the farm and features of the surrounding landscape (e.g. livestock facilities; Cook et al., 2011, 2018).…”

“…nectar and pollen) as adults did not feed on floral resources as immatures, instead the larvae of these species were mainly predators of small, soft bodied insects or detritivores (Davis, Bickel, et al., 2023). This suggests that crop‐pollinating flies need both floral and non‐floral resources to support their life cycle within agroecosystems, yet the non‐floral resource needs of crop‐pollinating flies is understudied (but see Davis, Bickel, et al., 2023; Davis, Schmidt, et al., 2023; Finch et al., 2023 for exceptions). It is therefore critical to document the basic life history needs (e.g.…”

Provisioning Australian Seed Carrot Agroecosystems with Non-Floral Habitat Provides Oviposition Sites for Crop-Pollinating Diptera

“…The abundance and diversity of insects that provide pollination services within agroecosystems often depend on suitable habitat options for the insects to complete their life cycles [ 1 , 2 ]. These habitats (e.g., remnant vegetation, semi-natural landscape features) are typically not within the crop system itself, but nearby, and provide food, reproduction sites, overwintering resources, and shelter from agricultural management practices such as tilling, harvesting, and pesticide application [ 3 , 4 , 5 , 6 , 7 ].…”