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Three behaviors of epidemiological importance, namely feeding latency, feeding duration and defecation latency, for six populations of Meccus phyllosomus longipennis (Usinger) from areas of central, western and north-central Mexico with high (HP) and low (LP) prevalence of Trypanosoma cruzi (Chagas) human infection were evaluated in this study. The median feeding latency (the time taken to begin feeding) was highly variable between instars. Within-instar comparisons showed that at least 65% of the LP populations (N3 to adult) started to feed significantly (P < 0.05) later than the HP population, with N1 showing no difference, and N2 from LP populations feeding sooner than those from HP populations. The six populations had similar median feeding durations within instars. A higher (P < 0.05) percentage of the instars from HP populations defecated faster than the respective instars from the three LP populations. Approximately 25% of the young nymphs (N1 to N3) and females in the HP populations defecated < 2 min postfeeding, compared with 4%-6% of the young nymphs and 1.3%-3% of females in the LP populations. Moreover, 17.7%-38.8% of the older nymphs (N4 to N5) in the HP populations and 6.8%-13.4% in the LP populations defecated during or immediately after feeding. Our results indicate that the HP populations have a greater potential than the LP populations to transmit T. cruzi infections, which may underlie the differences in the prevalence of T. cruzi infection in some areas where M. p. longipennis is currently distributed., (© 2020 Institute of Zoology, Chinese Academy of Sciences.)

Introduction: Different blood meal sources can affect biology of triatomines., Methods: We studied the influence of two different blood meal sources (rabbits and hens) on five biological parameters in Meccus phyllosomus pallidipennis and collected biological parameters., Results: The cohort fed on rabbits had a shorter median life-cycle and lower mortality rate than that fed on hens. Both cohorts required a similar number of blood meals to reach adulthood. Median longevity and number of blood meals for adults were similar between both cohorts., Conclusions: The studied parameters reflect the high grade of adaptation of M. p. pallidipennis feeding on different hosts.

The first record of Triatoma lecticularia out of its reported distribution area together with the brief description of the said area is provided in this paper. In addition, some biological parameters related to hatching of eggs, life cycle and feeding and defecation behaviors for each instar of one population of T. lecticularia from its previously reported distribution area (PR) and for each instar of that introduced recently found population (IS) of this species were evaluated and compared. Twenty-eight specimens were collected from IS, mostly (64.29%) from peridomestic areas (mainly chicken coops). No significant (p>0.05) differences were recorded between the two studied cohorts in their average time to hatch, which was close to 19days. The median egg-to-adult development time, the number of blood meals at each nymphal, the instar mortality rates and median time-lapse for beginning of feeding were significantly (p<0.05) shorter for the IS cohort. Median feeding time was higher in PR. Defecation delay was shorter than 10min in both studied cohorts. Given these results, the introduced recently found population of T. lecticularia could be considered an important potential vector of Trypanosoma cruzi to human populations and could replace main triatomine species on its new distribution area., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The values of biological parameters related to hatching, lifespan, the number of blood meals between moults, mortality, time lapse before the beginning of feeding, feeding time and defecation delay for each instar of three Mexican-American species of Triatominae, Triatoma recurva, Triatoma protracta (former subspecies protracta) and Triatoma rubida (former subspecies uhleri), were evaluated and compared. No significant (p > 0.05) differences were recorded among the three species with respect to the average time required to hatch. This time was approximately 19 days. The average egg-to-adult development time was significantly (p < 0.05) shorter for T. rubida. The number of blood meals at each nymphal instar varied from one-five for each species. The mortality rates were higher for the first-instar nymphs of the three species studied. The mean time lapse before the beginning of feeding was between 0.3-3 min for most nymphs of all instars of each species studied. The mean feeding time was the longest for T. recurva, followed by T. protracta. The defecation delay was less than 10 min for T. recurva and T. rubida. Given these results, only T. rubida should be considered an important potential vector of Trypanosoma cruzi transmission to humans in areas of Mexico where these species exist, whereas T. recurva and T. protracta would be of secondary importance.

Feeding time, postfeeding defecation delay, and life cycle for each stage of a cohort of recently colonized Mexican Triatoma dimidiata were evaluated, and results were compared to existing published information on this species. Seventy-five nymphs (41.7%) completed a cycle with an average time from N-I to adult of 142 +/- 64 days. The average span in days for each stage was 20.2 for N-I, 17.9 for N-II, 10.1 for N-III, 43.6 for N-IV, and 55.1 for N-V. First-stage nymphs had the highest mean feeding time (25 min) and the longest postfeeding defecation delay (45 min). Differences among biological data from previous studies and the present study confirm the importance of conducting research on the behavior of the indigenous triatomine species from various countries.