Journal of insect physiology
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Kissing bugs possess a highly developed thermal sense and when starved, they attempt to bite any object which temperature is close to that of a warm-blooded host. At each feeding event, these insects take massive meals in just a few minutes. One could then expect fed-bugs being heated-up by the ingested warm blood and so becoming attractive to starved conspecifics. ⋯ We tested this hypothesis by quantifying cannibalism by never-fed first-instar larvae on: (1) just-fed 5th instar bugs, (2) artificially heated just-fed bugs, (3) heated or (4) non-heated objects of the same size. In line with our hypothesis, non-heated just-fed bugs were not attacked by the 1st instar larvae, whereas heated bugs and object triggered biting behaviour in starved bugs, which performed either cleptohaematophagy or haemolymphagy on heated bugs. We conclude that cannibalism triggered by thermal stimuli has been one of the selection pressures that gave origin to thermoregulation during feeding on kissing bugs.
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Comparative Study
A critical test of Drosophila anaesthetics: Isoflurane and sevoflurane are benign alternatives to cold and CO2.
Anaesthesia is often a necessary step when studying insects like the model organism Drosophila melanogaster. Most studies of Drosophila and other insects that require anaesthesia use either cold exposure or carbon dioxide exposure to induce a narcotic state. These anaesthetic methods are known to disrupt physiology and behavior with increasing exposure, and thus ample recovery time is required prior to experimentation. ⋯ Sevoflurane had no measureable effect on any of the traits examined. Care must be taken when choosing an anaesthetic in Drosophila research, as the impacts of specific anaesthetics on stress tolerance, behavior and reproduction can widely differ. Sevoflurane may be a practical alternative to cold and CO2 anaesthesia in insects - particularly if flies are to be used for experiments shortly after anesthesia.
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Chronic exposure of acrylamide (ACR) leads to neuronal damage in both experimental animals and humans. The primary focus of this study was to assess the ameliorative effect of geraniol, (a natural monoterpene) against ACR-induced oxidative stress, mitochondrial dysfunction and neurotoxicity in a Drosophila model and compare its efficacy to that of curcumin, a spice active principle with pleiotropic biological activity. Adult male flies (8-10 days) were exposed (7 days) to ACR (5 mM) with or without geraniol and curcumin (5-10 μM) in the medium. ⋯ The neuroprotective effect of geraniol was comparable to curcumin in terms of phenotypic and biochemical markers. Based on our evidences in fly model we hypothesise that geraniol possess significant neuromodulatory propensity and may be exploited for therapeutic application in human pathophysiology associated with neuropathy. However, the precise mechanism/s by which geraniol offers neuroprotection needs to be investigated in appropriate neuronal cell models.
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We examined physiological phenotypes of Drosophila melanogaster in hypoxic to hyperoxic atmospheres. We performed measurements on life span or behavioural function in 5, 21, 40, 60, and 80% O(2), and combined this with literature data for 2% and 100% O(2). O(2) incubation resulted in a concentration-dependent reduction of life span in both hypoxia and hyperoxia, though different measures of life span were affected differently. ⋯ Because ageing results in generally irreversible functional declines, we examined if functional declines in hyperoxia (60% O(2)) were also irreversible, or whether some functioning could recover after a return to normoxia. After 7 days of recovery, water loss rates decreased, CO(2) exhalation slightly increased, and climbing ability was partially recovered. Therefore, the effect of O(2) on D. melanogaster function is non-linear, may be reversible, and may include unique phenotypes that arise at some O(2) concentrations, and not others.
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Bed bugs must avoid detection when finding hosts and returning to hidden harborages. Their stealthy habits include foraging when hosts are asleep. Characteristics of spontaneous locomotor activity rhythm of bed bugs with different feeding histories were studied. ⋯ While bed bugs can survive for a year or more without a blood meal, we observed a reduction in activity in insects held for five weeks without food. We suggest that bed bugs make a transition to host-stimulus dependent searching when host presence is not predictable. Such a strategy would enable bed bugs to maximize reproduction when resources are abundant and save energy when resources are scarce.