Biological Characteristics of Geographically Isolated Populations of Meccus mazzottii (Hemiptera: Reduviidae) in Southern Mexico

Abstract

Chagas disease, caused by Trypanosoma cruzi Chagas, is one of the most epidemiologically important vector-borne zoonoses in Mexico. Among the 32 reported triatomine species from Mexico, Meccus mazzottii (Usinger) (Hemiptera: Reduviidae) is one of the most important vectors of T. cruzi in the southern part of the country. Variability among populations of triatomines has been recorded for several species ( Meccus longipennis (Usinger) and Meccus pallidipennis (Stal)) that are closely related to M. mazzottii , showing an apparent influence of local environmental conditions on the biology of each population, which could modify the impact of vector control measurements. Therefore, this study sought to compare the biological features of populations of M. mazzottii from two geographically far apart areas that have similar environmental characteristics and to compare populations from close geographical areas that have different environmental characteristics. The mean longevity, percentages of mortality of nymphs, the total mean number of bloodmeals to molt (considered instar by instar), the mean number of eggs laid by females, and the percentage of hatched eggs were similar between the two localities that are geographically far apart but have similar environmental characteristics. On the other hand, important differences were noticed when a comparison was carried out on the two localities with similar environmental conditions with respect to that locality with different conditions, independent of geographic distance. Most of the studied parameters led us to conclude that the three studied populations are very highly influenced by local environmental conditions. The results of this study indicate the importance of studying the biological characteristics of local populations of triatomines to carry out specific control measurements, instead of using standard ones that could fail if they are not adapted to the target population.

Comparison of biological fitness in crosses between subspecies ofMeccus phyllosomus(Hemiptera: Reduviidae: Triatominae) in southern Mexico

“…The percentages of obtained females at the end of the life cycles were similar among all cohorts, as previously reported in studies about the 3 studied parental lines (Martínez‐Ibarra et al ., , ,b). Even when the numbers of eggs laid by the females were not statistically different among the studied cohorts, M. p. phyllosomus laid less than the average number of eggs compared with the other studied cohorts.…”

“…The egg eclosion rates of most of the studied cohorts (with the exception of M. p. phyllosomus ) are comparable with those of different species of triatomines (e.g., T. ryckmani Zeledón and Ponce, T. juazeirensis and T. patagonica Del Ponte) (Zeledón et al ., ; Lima‐Neiva et al ., ; Nattero et al ., ), as well as with those of the 3 parental lines, as identified in previous studies (Martínez‐Ibarra et al ., , a, b). Moreover, the average incubation period was approximately 19 d, indicating favorable maintenance conditions for the development of these groups.…”

“…This parameter also suggests some hybrid fitness. As reported for M. p. mazzotti , M. p. pallidipennis and M. phyllosomus (Martínez‐Ibarra et al ., , ,b), mortality in the youngest nymphs seemed to be caused by the feeding incapacity of insects because dead triatomines were generally found without significant intestinal content. On the other hand, the mortality of older nymphs seemed to occur during molting.…”

“…On initial collection, the founders of each colony were identified according to the Lent and Wygodzinsky () keys; the revalidation of Meccus was also taken into account (Carcavallo et al ., ; Bargues et al ., ), which corresponds to the typical morphologic characteristics of each species. Colonies were maintained at 27 ± 1 °C and 70% ± 5% relative humidity (RH), similar to the laboratory conditions in previously published studies on the biology of the 3 subspecies ( M. mazzottii , M. pallidipennis , and M. phyllosomus ) (Martínez‐Ibarra et al ., , ,b). Specimens were fed immobilized and anesthetized New Zealand rabbits fortnightly.…”

Importance of Hybrids of <i>Meccus phyllosomus mazzottii</i>, and <i>M. p. pallidipennis</i>, and <i>M. p. phyllosomus</i> to the Transmission of <i>Trypanosoma cruzi</i> in Mexico

“…(13) keys, taking into account the revalidation of the genus Meccus (2) and the corresponding morphological characteristics specific to each species. Colonies were maintained at 27 ± 19 C and 75 ± 5z relative humidity (rh), similar to the laboratory conditions in previously published studies on the biology of M. p. mazzottii, M. p. pallidipennis, and M. p. phyllosomus (24)(25)(26). They fed every two weeks on immobilized and anesthetized New Zealand rabbits.…”