Thermal preferences and limits of Triatoma brasiliensis in its natural environment - Field observations while host searching

Abstract

The goal of this work was to explore the thermal relationship between foraging Triatoma brasiliensis and its natural habitat during the hottest season in the state of Ceará, Brazil. The thermal profiles were determined using infrared analysis. Although the daily temperature of rock surfaces varied in a wide range, T. brasiliensis selected to walk through areas with temperatures between 31.7-40.5ºC. The temperature of T. brasiliensis body surface ranged from 32.8-34.4ºC, being higher in legs than the abdomen. A strong relationship was found between the temperature of the insect and the temperature of rock crevices where they were hidden (r: 0.96, p < 0.05). The species was active at full sunlight being a clear example of how the light-dark rhythm may be altered, even under predation risk. Our results strongly suggest a thermal borderline for T. brasiliensis foraging activity near 40ºC. The simultaneous determination of insect body and rock temperatures here presented are the only obtained in natural habitats for this or other triatomines.

Triatoma brasiliensis Neiva, 1911: food sources and diversity of Trypanosoma cruzi in wild and artificial environments of the semiarid region of Ceará, northeastern Brazil

“…In extreme natural conditions, in order to obtain a blood meal, T. brasiliensis exceeds microclimatic preferences established in the laboratory [36], and it is able to fiercely attack humans and animals, even during daylight [37, 38]. Feeding eclecticism and opportunism are striking characteristics of triatomines, which can suck blood from a wide variety of vertebrates [39].…”

Microsatellite variation revealed panmictic pattern for Triatoma brasiliensis (Triatominae: Reduviidae) in rural northeastern Brazil: the control measures implications

“…There was no genotypic differentiation when the first four surveys were compared pairwise ( F ST ), except in the comparison between the first (February 2009) and the last one (October 2010). Such homogeneity can be explained by high gene flow of T. brasiliensis in this region, well-known for its great capacity of dispersal and colonization of domiciliary ecotopes [ 21 , 37 – 40 ]. The difference between triatomines caught in the first and last surveys would reflect the elimination of preexisting triatomines following three insecticide applications (2009b, 2010a, 2010b) and the invasion of new specimens of T. brasiliensis into DUs over the 20-month period between these two surveys.…”

“…In sylvatic environments, T. brasiliensis is usually found in crystalline rock outcrops, associated especially with rodents, marsupials and bats [ 18 – 20 ]. It is an aggressive and opportunistic species, with very eclectic host-feeding behavior; hence it can colonize several ecotopes in widely diverse environments [ 18 , 21 , 22 ].…”

Fast recovery of house infestation with Triatoma brasiliensis after residual insecticide spraying in a semiarid region of Northeastern Brazil

“…The occurrence of house invasion and colonization increase with the proximity between natural and artificial ecotopes and the interactions among triatomines, synanthropic animals and humans [10][11][12]16,20,21]. The peridomicile contains multiple structures that provide shelter to triatomines, suitable microclimatic conditions, and diverse host sources [22][23][24][25]. The combined effects of refuges for triatomines in structures in which insecticides can hardly penetrate, high temperatures, wind, rainfall and insolation reduce the duration of pyrethroids residual effects [16,21,26,27].…”