Browsing by Autor "Hermann M. Niemeyer"

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Age-related anomalies of electrocardiograms in patients from areas with differential Seroprevalence of Chagas disease in Southern Bolivia
(Elsevier BV, 2021) Jhean-Carla Echalar; David Véliz; Omar N. Urquizo; Hermann M. Niemeyer; Carlos F. Pinto
Higher seroprevalence in rural population was attributable to a higher probability to encounter the vector in rural areas. Increased exposure to infection and to development of the disease symptoms together with increased lethality of the disease as patients age explains the age-related Chagasic electrocardiographic anomalies. Since rural and urban populations showed different reactions under Chagas disease and the rural population was mainly of guaraní stock, the genetic and environmental determinants of the results should be further explored.
Biology and Ecology of Alchisme grossa in a Cloud Forest of the Bolivian Yungas
(Oxford University Press, 2014) Daniel Torrico-Bazoberry; Liliana Alejandra Cáceres Sanchez; Daniela Saavedra-Ulloa; Luis Flores‐Prado; Hermann M. Niemeyer; Carlos F. Pinto
Treehoppers (Membracidae) exhibit different levels of sociality, from solitary to presocial. Although they are one of the best biological systems to study the evolution of maternal care in insects, information on the biology of species in this group is scarce. This work describes the biology and ecology of Alchisme grossa (Fairmaire) (Hemiptera: Membracidae) in a rain cloud forest of Bolivia. This subsocial membracid utilizes two host-plant species, Brugmansia suaveolens (Humb. & Bonpl. ex Wild) Bercht. & J.Presl and Solanum ursinum (Rusby) (both Solanaceae), the first one being used during the whole year and the second one almost exclusively during the wet season. The development of A. grossa from egg to adult occurred on the plant where eggs were laid. Maternal care was observed during the complete nymphal development, and involved behavioral traits such as food facilitation and antidepredatory defense. Life cycle was longer on B. suaveolens during the dry season and shorter on S. ursinum during the wet season. Mortality was similar on both host plants during the wet season but was lower on B. suaveolens during the dry season. The presence of a secondary female companion to the egg-guarding female individual and occasional iteropary is also reported.
Biology, ecology and demography of the tropical treehopper <scp>E</scp> nnya maculicornis ( <scp>H</scp> emiptera: <scp>M</scp> embracidae): relationships between female fitness, maternal care and oviposition sites
(Wiley, 2017) Liliana Alejandra Cáceres Sanchez; Daniel Torrico-Bazoberry; ROMINA COSSIO; KENIA REQUE; Sandra Aguilar; Hermann M. Niemeyer; Carlos F. Pinto
1. Treehoppers ( H emiptera: M embracidae) exhibit a wide range of social behaviours related to maternal care and nymphal aggregation. Maternal care represents an investment in terms of time and energy leading to trade‐offs which bear a strong relationship with parity and can thus affect population dynamics. These trade‐offs can be modulated by biotic and abiotic features of the oviposition site. 2. Preliminary observations on E nnya maculicornis ( M embracidae: S imilinae: P olyglyptini) show that females generally lay a single egg mass, and occasionally two or three egg masses, and that maternal care is a plastic trait because some females abandoned their egg mass before it hatched while other females remained with their offspring after egg hatching. These features make this species an interesting model to study the relationship between female fitness, maternal care and ecological factors such as oviposition site. 3. The biology and natural history of E . maculicornis are described and the relationships in question analysed using demographic parameters estimated by matrix models. E nnya maculicornis showed sexual dimorphism and a longer developmental period than other species of the same tribe. Females exhibited maternal care that increased offspring survival, and preferred mature over young host leaves for oviposition. Finite rate of increase ( λ ) values were lower than 1, suggesting a tendency towards population decrease. 4. The results represent the first detailed description of the life history and ecology for a species of this genus. Additionally, new hypotheses for treehopper sexual dimorphism, oviposition site choice and the ecological effects on population dynamics are proposed.
Demographic and performance effects of alternative host use in a Neotropical treehopper (Hemiptera: Membracidae)
(Elsevier BV, 2019) Carlos F. Pinto; Daniel Torrico-Bazoberry; Luis Flores‐Prado; Ramiro O. Bustamante; Hermann M. Niemeyer
Kin recognition in a subsocial treehopper ( <scp>H</scp> emiptera: <scp>M</scp> embracidae)
(Wiley, 2018) Daniel Torrico-Bazoberry; Liliana Alejandra Cáceres Sanchez; Luis Flores‐Prado; Daniel Aguilera‐Olivares; Francisco E. Fontúrbel; Hermann M. Niemeyer; Carlos F. Pinto
1. Insects exhibiting parental care usually can discriminate between kin and non‐kin individuals, allowing parents to avoid investment in foreign offspring. 2. This study investigated the occurrence of kin recognition in the sap‐feeding insect Alchisme grossa Fairmaire (Membracidae) through bioassays assessing median female distance to nymphs and degree of nymphal aggregation. Each bioassay involved groups consisting of a female and a cohort of kin or non‐kin nymphs (mother and non‐mother treatments, respectively). Furthermore, cuticular non‐volatile compounds were extracted from nymphal cohorts, analysed by gas chromatography‐mass spectrometry and compared between cohorts. 3. In both treatments, nymphs performed a ‘rocking behaviour’ which appears to be correlated with aggregation. Temporal patterns of degree of nymphal aggregation and median female–nymph distance differed between treatments, the former parameter being higher in the mother treatment and the latter being higher in the non‐mother treatment. 4. A total of 40 compounds were found in the extracts. The composition of cuticular non‐volatile compounds differed between nymphal cohorts. 5. These results support the notion that kin recognition in A. grossa is possibly mediated by nymphal rocking behaviour and/or cuticular non‐volatile compounds (i.e. visual and/or chemical cues).
Mate searching in Ennya maculicornis (Membracidae: Polyglyptini) initiated by females: behavioural and acoustic descriptions
(Wiley, 2019) Romina Cossio‐Rodríguez; Reginald B. Cocroft; Hermann M. Niemeyer; Carlos F. Pinto
1. In treehoppers in which courtship has been studied, males initiate the search for females by periodically emitting a vibrational signal. The responses by the female are used by males as a beacon and give rise to a duet. 2. Courtship and mating of the treehopper Ennya maculicornis were characterised through the simultaneous recording of vibrational signals and the behaviour of males and females in an arena. 3. In E. maculicornis , female initiated mate searching. Females produced two types of signals during the this process: (i) a signal that preceded the approach by the male and (ii) a signal that preceded mating. Males emitted two signals associated with two stereotyped body movements: (i) a signal produced as a response to the first signal emitted by the female, involving a change in the male's locomotory mode and the approach to the female, and (ii) a signal produced after finding and holding on to the female, involving simultaneous abdomen raising and wing fluttering. These signals were repeated several times before the female emitted the second signal. The four signalling patterns were observed in all recordings in which mating was observed. When any of the signals was missing, mating did not occur. 4. Female‐biased sex ratios in E. maculicornis , along with iteroparity, are suggested to explain the initiation of mate searching behaviour by females. A comparison of data with that from other treehoppers indicates that vibrational signals and their associated behaviour are more diverse among treehoppers than has been appreciated previously.
Natural selection in the tropical treehopper Alchisme grossa (Hemiptera: Membracidae) on two sympatric host-plants
(Springer Science+Business Media, 2016) Daniel Torrico-Bazoberry; Carlos F. Pinto; Luis Flores‐Prado; Francisco E. Fontúrbel; Hermann M. Niemeyer
Pollen Preference Patterns by Tetragonisca angustula (Apidae: Meliponini) in a Boliviano–Tucumano Forest
(Springer Nature, 2022) Omar N. Urquizo; Fabricio Cardozo-Alarcón; M. Adler; Reinaldo Lozano; Selmy Calcina-Mamani; Kathy Collao-Alvarado; Hermann M. Niemeyer; Carlos F. Pinto
Pollen Types Used by the Native Stingless Bee, Tetragonisca angustula (Latreille), in an Amazon-Chiquitano Transitional Forest of Bolivia
(Springer Nature, 2018) Alexandria Saravia-Nava; Hermann M. Niemeyer; Carlos F. Pinto
Pollination systems and nectar rewards in four Andean species of Salvia (Lamiaceae)
(Canadian Science Publishing, 2023) Alexandria Saravia-Nava; Santiago Benitez‐Vieyra; Omar N. Urquizo; Hermann M. Niemeyer; Carlos F. Pinto
Adaptation to the most effective pollinator is often conceived as the primary explanation of widespread convergence in flower phenotypes. However, specialization does not exclude the presence of other floral visitors, which may contribute to plant reproduction. Here we combined observations about pollinators’ visitation rates and effectiveness with nectar secretion dynamics and sugar composition in four Andean Salvia species from Bolivia. The study revealed a wider diversity than expected both in pollination systems and in nectar strategies. While Salvia haenkei Benth. and Salvia stachydifolia Benth. were almost exclusively pollinated by either hummingbirds or bees, respectively, mixed pollination was found in Salvia orbignaei Benth., a species previously described as hummingbird-pollinated. Salvia personata Epling. was exclusively pollinated by syrphid flies. Differences in nectar volume and sugar concentration were found between insect-pollinated species and mixed- or hummingbird-pollinated species. However, the four Salvia species displayed different strategies regarding nectar sugar composition, with sucrose-rich nectar in Salvia orbignaei, glucose-rich nectar in Salvia haenkei and Salvia stachydifolia, and glucose-rich nectar lacking fructose in Salvia personata, suggesting an adaptation to syrphid fly pollination. Our results provide a clearer picture of floral trait evolution in Salvia and highlight the contribution of some pollinators different from those expected according to the floral syndromes.
Repellent activity of the essential oil from Laurelia sempervirens (Ruiz & Pav.) Tul. (Monimiaceae) on Triatoma infestans (Klug) (Reduviidae)
(University of Santiago, 2020) Marycruz Mojica; Raúl A. Alzogaray; Sofía L. Mengoni; Mercedes María Noel Reynoso; Carlos F. Pinto; Hermann M. Niemeyer; Javier Echeverría; Centro de Investigaciones de Plagas e Insecticida; Carlos Pinto; Universidad Mayor Real y Pontificia de San Francisco Xavier de Chuquisaca
Triatoma infestans (Klug) is the principal vector of Chagas disease in Bolivia and neighboring countries. The objective of this study was to determine the chemical composition of the EO of the Chilean laurel, Laurelia sempervirens (Ruiz & Pav.) Tul. (Monimiaceae) and to evaluate its repellent effect on fifth-instar nymphs of T. infestans. The EO from L. sempervirens was obtained by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). Their main components were cis-isosafrole (89.8%), terpinene (3.9%), trans-ocimene (2.7%) and methyleugenol (2.2%). Repellency was evaluated on a circle of filter paper divided into two equal zones which were impregnated with test substances [EO or N,N-diethyl-3-methylbenzamide (DEET) as positive control] and acetone as blank control, respectively. Several concentrations of test substances between 4.125 and 132 g/cm 2 were tested. The EO from L. sempervirens produced significant repellency at concentrations equal or above 66.0 g/cm 2 , while DEET repelled starting at 16.5 g/cm 2 . Future works will be oriented to the study of repellent properties of cis-isosafrole alone and mixed with -terpinene, trans-ocimene and methyleugenol on T. infestans.
Reproductive and brood-rearing strategies in Alchisme grossa (Hemiptera: Membracidae): genetic analyses of kinship relationships
(Springer Nature, 2020) Omar N. Urquizo; David Véliz; Daniel Torrico-Bazoberry; Caren Vega‐Retter; Luis Flores‐Prado; Hermann M. Niemeyer; Carlos F. Pinto
Response to selected ecological parameters by Leptus hringuri Haitlinger, 2000 larvae (Trombidiformes: Erythraeidae) parasitizing treehoppers (Hemiptera: Membracidae) from Bolivia on two host-plant species
(Taylor & Francis, 2020) Daniel Torrico-Bazoberry; Carlos F. Pinto; Joselina Davyt-Colo; Hermann M. Niemeyer
Larvae of Leptus hringuri parasitizing families (adult female + offspring) of the treehopper Alchisme grossa on two host-plants, Brugmansia suaveolens (BS) and Solanum ursinum (SU), were studied. The effect of microenvironmental abiotic conditions (luminosity, temperature and relative humidity) and biotic conditions (distance from the soil to a treehopper host and host-plant phenological stage) on this tritrophic interaction was examined. Overall, the results suggest i) intensity of mite infestation (mean number of mites per infested female or family) of treehoppers (insect hosts) was twice on SU than on BS, ii) a preference of L. hringuri larvae for places with more luminosity (on both host-plants) and relative humidity (on SU), iii) a negative correlation between larval infestation and distance of the host colony to the ground, and iv) that larvae of L. hringuri could detect cues (i.e. chemical) emitted by their insect hosts or the host-plant of the insect host. Results indicate that luminosity, humidity and distance to the ground of the insect-host microenvironment affect both parasitization and prevalence of Leptus larvae mites; however, further research will be needed to understand the ecological mechanisms and consequences of these interactions and to test the hypotheses proposed herein under a chemical ecology perspective.
Sequestration of tropane alkaloids from Brugmansia suaveolens (Solanaceae) by the treehopper Alchisme grossa (Hemiptera: Membracidae)
(Elsevier BV, 2016) Carlos F. Pinto; Silvia Salinas; Luis Flores‐Prado; Javier Echeverría; Hermann M. Niemeyer
Smoke of Capsicum baccatumL. var. baccatum (Solanaceae) repels nymphs of Triatoma infestans(Klug) (Hemiptera: Reduviidae)
(University of Santiago, 2021) Jhean-Carla Echalar; Romina Cossio‐Rodríguez; David Véliz; Fabricio Cardozo-Alarcón; Hermann M. Niemeyer; Carlos F. Pinto; Fabricio Cardozo-Alarcon; Universidad Mayor Real y Pontificia de San Francisco Xavier de Chuquisaca; Hermann M. Niemeyer; Universidad de Chile
Control of the Chagas disease vector, Triatoma infestans(Klug) (Hemiptera: Reduviidae) with synthetic pesticides in Bolivia has become increasingly inefficient due to the development of resistance in the insects. In the Chaco region of Bolivia, guaraní populations have approached the problem by fumigating their houses with the smoke of native plants. Through interviews and field work with local guides, the main plant used by the guaraníes was collected and later identified as Capsicum baccatumL. var. baccatum(Solanaceae). In choice bioassays, filter papers exposed to the smoke of the plant repelled nymphs of T. infestans. Activity remained significant after storing the exposed filter papers for 9 days. Chemical analysis of smoke and literature data suggested that capsaicinoids present in the smoke were responsible for the repellent effect. The data presented provide a rationale for the use of C. baccatumvar. baccatumto control the Chagas vector bythe guaraní populations.