ORCID Profile
0000-0002-5440-6706
Current Organisation
University of Western Australia
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Publisher: Elsevier BV
Date: 2020
Publisher: Wiley
Date: 03-07-2023
DOI: 10.1111/JEN.13159
Abstract: Avocado pollination remains a major focus for producers as fruit‐set is typically very low (less than 1%). Most avocado producers in Australia utilize honey bees ( Apis mellifera ) to improve yield however, there are risks with reliance on one species for future pollination security. Flies regularly visit flowers including avocado flowers. However, their pollination ability is poorly understood. To address this, visual observations of flies foraging in avocado orchards along with releases of two species of blow fly (within replicate enclosures of paired avocado trees Hass and Type B cultivars) were conducted at a commercial orchard in south‐western Western Australia. Visual observations during flowering identified that most non‐bee flower visits were by hover flies ( Melangyna viridiceps and Sphaerophoria macrogaster ) and blow flies ( Calliphora vicina and C. albifrontalis ). Hover flies mostly foraged on flowers in the morning while blow flies were generally more active in the afternoon. Pollination as measured by harvestable fruit was higher by C. dubia (45.6 ± 10.0) than by C. albifrontalis . (26.3 ± 6.6). Compared with open trees pollinated by bees and other insects present, trees pollinated by C. dubia produced nearly two‐thirds the number of fruit. When presented with equal numbers of avocado flowers, C. dubia fed three times more often than C. albifrontalis , which may explain their higher pollination rate. Both C. dubia and C. albifrontalis transferred on average one pollen grain/flower visit. Blow flies improved avocado yield above no insect pollinators (3 fruit/tree) by an average of 31 fruit/tree (across both fly species), but considerably less than trees in the open pollinated by honey bees (128 fruit/tree). Future trials with multi‐tree enclosures will assess avocado pollination by different fly species. This study demonstrated that at least one species of blow fly could pollinate avocado and provide potential as a managed pollinator in Australian horticulture.
Publisher: Wiley
Date: 25-01-2023
DOI: 10.1111/PHEN.12404
Abstract: Insect larvae typically moult to grow, but here we investigate insect larvae that moult to shrink that is, retrogressive moulting or retrogressive development. We demonstrate this phenomenon in khapra beetle, Trogoderma granarium Everts (Dermestidae), among the world's most invasive pests of stored grains and cereal products, and a quarantine pest of interest for many countries. Larvae survived a 3‐month period of starvation, moulting up to six times and reducing their body mass by about half, on average. When reprovisioned with food, most larvae resumed the normal trajectory of development and pupated within a month. Thus, retrogressive development is a mechanism that may favour species whose resources exhibit feast‐or‐famine dynamics. By enabling survival during periods of privation, retrogressive development contributes to the invasiveness of the khapra beetle by allowing them to persist for long periods in empty storage facilities or empty containers used for international grain shipments.
Publisher: Oxford University Press (OUP)
Date: 06-12-2020
DOI: 10.1093/JEE/TOZ316
Abstract: Khapra beetle, Trogoderma granarium Everts, is unusual in two key respects. First, they are among the most cold hardy of stored-product insect pests even though they originate in hot and dry regions of the Indian subcontinent. Second, their larvae can enter into diapause to survive harsh environmental conditions. In the present study, we examined whether these two phenomena are related, i.e., due to cross-tolerance. Cross-tolerance is the tolerance to one ecological stress when induced by a separate stress. To investigate this, khapra beetle larvae were reared at different relative humidities (3, 28, 49, and 79%) in either nondiapausing or diapausing conditions. Then the cold tolerance of larvae was estimated by measuring mortality after different durations at −10°C. For nondiapausing larvae, relative humidity had little effect on cold tolerance with the lethal time to 50% mortality (LT50) occurring between 2 and 4 d. For diapausing larvae, cold tolerance increased with greater desiccation stress with LT50’s of 5, 7, 10, and 18 d at 79, 49, 28, and 3% RH, respectively. This suggests that the physiological mechanisms that protect diapausing larvae from desiccation may also increase cold tolerance, even though these insects may rarely be exposed to low temperatures.
Location: Australia
No related grants have been discovered for Sunil Shivananjappa.