scholarly journals The role of the ocelli in the phototactic behaviour of the haematophagous bug Triatoma infestans

1998 ◽  
Vol 44 (12) ◽  
pp. 1159-1162 ◽  
Author(s):  
Claudio R Lazzari ◽  
Carolina E Reiseman ◽  
Teresita C Insausti
Keyword(s):  
Triatoma Infestans ◽  
Phototactic Behaviour

The role of blood intake in density regulation of populations of Triatoma infestans (Klug) (Hemiptera: Reduviidae)

1982 ◽  
Vol 72 (4) ◽  
pp. 617-629 ◽  
Author(s):  
C. J. Schofield
Keyword(s):  
Population Density ◽  
Triatoma Infestans ◽  
Female Fecundity ◽  
Density Regulation ◽  
Dependent Relationship ◽  
Development Times ◽  
Different Temperatures ◽  
Development Processes ◽  
The Difference

AbstractThe growth of populations of Triatoma infestans (Klug) depends on temperature and blood-intake. Experiments are described which demonstrated the density-dependent relationship between population size, blood intake and population growth at different temperatures. The number of bugs feeding and their mean blood intake was lower at high bug densities than at low ones, both with restrained chickens and with unrestrained mice as hosts. When blood intake was restricted, the development times of all nymphal stages were increased, and female fecundity was decreased. Previous work showed also that reduced blood intake led to an increased tendency for adult flight. It is thought that at high bug density the three factors, increased development times, decreased fecundity and increased flight, operate to restore the population to a stable density without promoting an increase in mortality. The mechanism linking population density to nutritional status seemed to depend on host irritability, which interrupted the bugs' feeding. Bugs which passed a certain threshold meal size would not resume feeding if interrupted, even though their blood intake was well below normal. The difference between the minimal threshold meal and a normal meal is thought to provide the nutritional elasticity within which the development processes are regulated. It is suggested that this mechanism is characteristic of K-strategists, whereas r–strategists such as mosquitoes tend to continue attacking, even if interrupted, until they achieve a normal meal.

The role of the antennae in Triatoma infestans: Orientation towards thermal sources

1996 ◽  
Vol 42 (5) ◽  
pp. 433-440 ◽  
Author(s):  
Graciela B. Flores ◽  
Claudio R. Lazzari
Keyword(s):  
Triatoma Infestans ◽  
Thermal Sources

Phototactic behaviour and the role of light in host transmission of Bursaphelenchus xylophilus

Nematology ◽  
2018 ◽  
Vol 20 (10) ◽  
pp. 917-923
Author(s):  
Zhitao Xia ◽  
Liqun Bai ◽  
Bicheng Sheng ◽  
Xingyao Zhang ◽  
Stefan Schütz ◽  
...  
Keyword(s):  
Positive Response ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Mixed Population ◽  
Negative Response ◽  
Fourth Stage ◽  
Orange Yellow ◽  
Role Of Light ◽  
Phototactic Behaviour

Summary The pine wood nematode (PWN) Bursaphelenchus xylophilus is the causal agent of pine wilt disease (PWD). To understand the light influence on PWN, we investigated its phototactic behaviour. Our data indicated the mixed population of propagative PWN had a positive response to red, orange, yellow, green, blue and white lights, but a weak negative response to violet. For age-synchronised propagative nematodes, however, phototactic behavioural features changed with development. Interestingly, the dispersal fourth-stage juveniles (JIV) showed negative response to all tested lights, which was almost completely the reverse of the propagative fourth-stage juveniles (J4). Further bioassays proved that green, blue and white lights suppressed the host transmission of dispersal JIV from vector beetle to healthy pine branches. Our results revealed that night could be the peak of host transmission. With the results of previous studies, we speculate volatiles from the host tree and light may play pull-and-push roles to accelerate the host transmission of B. xylophilus.

Insecticide Resistance Mechanisms in Triatoma infestans (Reduviidae: Triatominae): The Putative Role of Enhanced Detoxification and Knockdown Resistance (kdr) Allele in a Resistant Hotspot From the Argentine Chaco

2020 ◽  
Vol 57 (3) ◽  
pp. 837-844 ◽  
Author(s):  
Georgina Fronza ◽  
Gonzalo Roca-Acevedo ◽  
Gaston A Mougabure-Cueto ◽  
Ivana Sierra ◽  
Natalia Capriotti ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Control Strategies ◽  
Disease Incidence ◽  
Molecular Study ◽  
Resistance Mechanisms ◽  
Triatoma Infestans ◽  
Pyrethroid Insecticides ◽  
Degradative Enzymes ◽  
A Minor

Abstract Chagas disease affects around 6 million people in the world, and in Latin America, it is mainly transmitted by the kissing bug. Chemical control of the vector with pyrethroid insecticides has been the most frequently used tool to reduce the disease incidence. Failures of field control have been detected in areas of the Argentinian Gran Chaco that correlate with high levels of insecticide resistance. Here, we provide evidence of the mechanisms involved in the resistance to insecticides of field populations of T. infestans from General Güemes Department (Chaco Province, Argentina). The biochemical analysis suggests the increase in the activity of the degradative enzymes P450 oxidases and esterases as a minor contributive mechanism in low-resistance populations. The molecular study revealed high frequencies of the kdr L925I mutation at the voltage-gated sodium channel as responsible for the high resistance ratios detected. This knowledge contributes to the generation of comprehensive vector control strategies that reduce the incidence of the disease.

Novel cysteine proteinase inTrypanosoma cruzimetacyclogenesis

Parasitology ◽  
2005 ◽  
Vol 132 (3) ◽  
pp. 345-355 ◽  
Author(s):  
V. G. DUSCHAK ◽  
M. BARBOZA ◽  
G. A. GARCÍA ◽  
E. M. LAMMEL ◽  
A. S. COUTO ◽  
...  
Keyword(s):  
Cysteine Proteinase ◽  
Apparent Molecular Weight ◽  
Triatoma Infestans ◽  
Cysteine Proteinase Inhibitor ◽  
Molecular Weight Range ◽  
Elution Pattern ◽  
Endopeptidase Activity ◽  
Culture Supernatants ◽  
Different Order

With the aim to study proteinases released to the culture medium duringTrypanosoma cruzimetacyclogenesis, the presence of cysteine proteinases (CPs) was analysed in culture supernatants obtained throughout the differentiation induced by stimulation of epimastigotes withTriatoma infestanshindgut homogenate. In SDS-gelatin containing gels, an important endopeptidase activity with apparent molecular weight range between 97 and 116 kDa was encountered at pH 6, which was abolished by the specific cysteine proteinase inhibitor E-64 and TLCK, but not by pepstatin, 1,10 phenantroline or PMSF. This novel CP, namedTcCPmet, showed affinity to cystatin-Sepharose, denoting its thiol-proteinase character as well as to ConA-Sepharose, indicating it contains N-linked oligosaccharides. However, it presented a different elution pattern on ConA-Sepharose than cruzipain and, in addition, it was not recognized by anti-cruzipain serum, facts that strongly suggest the different nature of both CPs. Moroever, evidence is presented indicating thatTcCPmet was able to hydrolyse the same chromogenic peptides as cruzipain at optimal alkaline pH values, although with a different order of effectiveness. Our results indicate the presence of a novel CP secreted by metacyclic trypomastigotes and reinforces the important role of these enzymes in metacyclogenesis.

scholarly journals Role of enhanced detoxication in a deltamethrin-resistant population of Triatoma infestans (Hemiptera, Reduviidae) from Argentina

2004 ◽  
Vol 99 (3) ◽  
pp. 335-339 ◽  
Author(s):  
Paola González Audino ◽  
Claudia Vassena ◽  
Silvia Barrios ◽  
Eduardo Zerba ◽  
María Inés Picollo
Keyword(s):  
Triatoma Infestans ◽  
Resistant Population
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