Circadian entrainment by light and host in the Chagas disease vector, Triatoma infestans (original) (raw)
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Circadian organization of locomotion activity in the haematophagous bug Triatoma infestans
Journal of Insect Physiology, 1992
Daily locomotor activity of Triatoma irzfistans adults exhibits two major components, one at the second hour of the scotophase and a second one at the beginning of the photophase. The occurrence of peaks can be ascribed to food and refuge search at dusk and dawn, respectively. Both maxima appear under discrete light-dark regimes (12 h light-12 h dark, 25 : 0 lx) at constant temperature, as well as under discrete high-low temperature cycles 12 h at 3O"C-12 h at 20°C in continuous light or in darkness. Under constant darkness, both maxima of activity display different freerunning periods (z, x 23 h 50 min, z, e 22 h 15 min), suggesting the involvement of two oscillators controlling, individually, the two activity peaks. Under continuous light, however, activity becomes unimodal, freerunning at r % 26 h 40 min. Resetting a 180" shift of high-low temperature cycles occurs faster than by light-dark cycles. In conditions of zeitgeber competition, by simultaneous exposition to light and temperature cycles at various phase relationships, light preponderantly controls the synchronization of activity. Results indicate that the activity of T. infestuns is controlled by a circadian system involving a hierarchical arrangement of coupled oscillators. Environmental temperature modulates the activity level and the time course of the spontaneous locomotion. Antennectomy affects the temporal expression of the activity, insects becoming active at an unusual daytime.
Trypanosoma cruzi Parasite Load Modulates the Circadian Activity Pattern of Triatoma infestans
Insects
American trypanosomiasis is a disease caused by the flagellate protozoan Trypanosoma cruzi, which is transmitted mainly in endemic areas by blood-sucking triatomine vectors. Triatoma infestans is the most important vector in the southern cone of South America, exhibiting a nocturnal host-seeking behavior. It has been previously documented that the parasite produces changes in some triatomine species, but this is the first time that the behavior of a vector has been evaluated in relation to its parasite load. After comparing the movement events and distance traveled of infected and non-infected T. infestans, we evaluated the change produced by different T. cruzi parasite loads on its circadian locomotor activity. We observed differences between infected and non-infected triatomines, and a significant relation between the parasite load and the increase in locomotor activity of T. infestans, which was accentuated during the photophase. This could have direct implications on the transmi...
Daily Rhythms in Disease-Vector Insects
Biological Rhythm Research, 2004
The host-vector-parasite interaction offers a clear illustration of the adaptive value of biological rhythms. In this review, we summarise some of the information currently available on daily rhythms of insect vectors, particularly those responsible for the transmission of parasites to humans. Included amongst the cases described are circadian rhythms of locomotor and flight activity, and of eclosion and oviposition in tsetse flies, blood-sucking hemipterans, mosquitoes and other haematophagous insects. Both published and new data are presented, and they indicate that a study of the rhythms in disease-vector insects can provide an understanding of the value of this application of chronobiology to ecology and applied sciences. Related to this, the possibility of strategies for the control of insects based on their temporal characteristics is proposed; for example, the use of insecticides could be restricted to those phases of the day when the susceptibility of the insects to them is increased.
FEBS Letters, 2006
Despite the importance of circadian rhythms in vector-borne disease transmission, very little is known about its molecular control in hematophagous insect vectors. In Drosophila melanogaster, a negative feedback loop of gene expression has been shown to contribute to the clock mechanism. Here, we describe some features of the circadian clock of the sandfly Lutzomyia longipalpis, a vector of visceral leishmaniasis. Compared to D. melanogaster, sandfly period and timeless, two negative elements of the feedback loop, show similar peaks of mRNA abundance. On the other hand, the expression of Clock (a positive transcription factor) differs between the two species, raising the possibility that the different phases of Clock expression could be associated with the observed differences in circadian activity rhythms. In addition, we show a reduction in locomotor activity after a blood meal, which is correlated with downregulation of period and timeless expression levels. Our results suggest that the circadian pacemaker and its control over the activity rhythms in this hematophagous insect are modulated by blood intake.
Circadian control of photonegative sensitivity in the haematophagous bug Triatoma infestans
Journal of Comparative Physiology A: Sensory, Neural, and Behavioral Physiology, 1998
The negative phototactic response of Triatoma infestans (Hemiptera) was studied in an arena, half of which was kept dark and the other half illuminated with dierent light intensitites. For each intensity we measured the time the insects spent in the dark half, the time to reach the side opposite to that where they were released, and the number of passages through the middle line of the arena. T. infestans displayed a photonegative behaviour that was enhanced by high light intensities.
Journal of Medical Entomology, 2021
Mepraia spinolai, (Porter) 1934, is a diurnal triatomine endemic to Chile and a wild vector of the protozoan Trypanosoma cruzi, (Chagas) 1909, which causes Chagas disease. Behavioral changes in M. spinolai induced by this parasite have been reported previously, which include detection of a potential host, defecation latency, and some life history traits. In this study we assessed changes in locomotor and daily activity due to infection with T. cruzi. No difference was detected in distance traveled between infected and uninfected individuals. However, the groups differed in their daily activity patterns; infected individuals showed significant reduction of movements during the light phase and concentrated their activity in the dark phase. Uninfected individuals showed no differences in locomotor activity between the phases. The results suggest that T. cruzi induces a displacement in the activity of M. spinolai toward the dark phase of the circadian cycle, which may improve its vector...
Circadian rhythm of spontaneous locomotor activity in the bed bug, Cimex lectularius L
Journal of Insect Physiology, 2010
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. In the absence of host stimuli, adults and nymphs were much more active in the dark than in the light. The onset of activity in the scotophase commenced soon after lights-off. The free-running period (t) for all stages was longer in continuous darkness (DD) than in continuous light (LL). The lengthening of t in DD is an exception for the circadian rule that predicts the opposite in nocturnal animals. Activity in all stages was entrained to reverse L:D regimes within four cycles. Short-term starved adults moved more frequently than recently fed adults. 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. ß
Circadian modulation of learning ability in a disease vector insect, Rhodnius prolixus
The Journal of experimental biology, 2015
Despite the drastic consequences it may have on the transmission of parasites, the ability of disease vectors to learn and retain information has just begun to be characterised. The kissing bug Rhodnius prolixus, a vector of Chagas disease, is an excellent model, particularly because conditioning the proboscis extension response (PER) constitutes a valuable paradigm to study their cognitive abilities under carefully controlled conditions. Another characteristic of these bugs is the temporal organisation of their different activities in a bimodal endogenous daily rhythm. This offers the opportunity to address the implication of the circadian system in learning and memory. Using aversive conditioning of the PER, we tested whether the ability of kissing bugs to learn and remember information varies during the day. We found that bugs perform well during the night, but not during the day: their ability to acquire information - but not their ability to retrieve it - is modulated by time. ...
Circadian Organization in Hemimetabolous Insects
Zoological Science, 2004
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Clock Gene Period in the Chagas Disease Vector Triatoma infestans (Hemiptera: Reduviidae)
The American journal of tropical medicine and hygiene, 2017
To contribute to a better understanding of the molecular bases of the circadian biological rhythms in Chagas disease vectors, in this work we identified functional domains in the sequences of the clock protein PERIOD (PER) in Rhodnius prolixus and Triatoma infestans and analyzed the expression of the PER gene at mRNA level in T. infestans. The PER protein sequences comparison among these species and those from other insects revealed that the most similar regions are the PAS domains and the most variable is the COOH-terminal. On the other hand, the per gene expression in nervous tissue of adult T. infestans varies with a daily canonical rhythm in groups of individuals maintained under photoperiod (light/dark, LD) and constant dark (DD), showing a significant peak of expression at sunset. The pattern of expression detected in LD persists under the DD condition. As expected, in the group maintained in constant light (LL), no daily increase was detected in per transcript level. Besides,...