Electroantennogram responses of the Triatoma dimidiata complex to volatiles produced by its exocrine glands.

Members of the Triatoma dimidiata complex are vectors of the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease. Morphological and genetic studies indicate that T. dimidiata complex has three principal haplogroups in Mexico. However, whether there are differences in the olfactory physiology among the haplogroups of this complex and a possible correlation with their antennal phenotype are not yet known. Antennal responses to 13 compounds released from the metasternal and Brindley´s glands, which are involved in the alarm and mating-related behaviours of T. dimidiata were investigated using electroantennography (EAG). Overall, of the 13 compounds tested, seven triggered EAG responses in both sexes of three Mexican haplogroups. The sensitivity of the EAG responses show some relationship with the total number of chemo-sensilla present on the antennae. Antennal sensitivity was different between sexes and haplogroups of the T. dimidiata complex. Discriminant analysis of EAG sensitivity was significant, separating the three haplogroups. Our finding is consistent with morphological and genetic evidence for haplogroups distinction within the complex.

Phenotypic Variability of the Amazonian Species Rhodnius brethesi (Hemiptera: Reduviidae).

The wild species Rhodnius brethesi (Matta, 1919) (Hemiptera: Reduviidae) is found in areas of piassabais in microregion of Rio Negro, Amazonas, Brazil. Its geographical distribution overlaps the areas of Leopoldinia piassaba palm. In areas where palm trees are found, transmission cycle of Trypanosoma cruzi is related to the extractive activity of the palm fiber, exposing workers to wild vector transmission of this parasite. The close association with the palm tree L. piassaba suggests that this wild triatomine has special features in its sensory system allowing specificity of ecotope. The objective of the study is to identify the antennal sensilla phenotype and morphologically characterize the size and shape of the wings of wild R. brethesi, and to compare with the phenotype present in individuals reared in the laboratory. From the samples taken in the field, the presence of the species R. brethesi was found on both banks of the Rio Negro. The techniques used to verify the morphological patterns are important resources for observations of the triatomine populations, be they in an artificial or natural habitat.

Maintaining professional activity during breast cancer treatment.

The question of returning to work and pursuing professional activity during cancer treatment is an increasingly important consideration. The present work focuses on factors affecting the feasibility of maintaining professional activity during treatment for breast cancer, for women who wished to do so. Written questionnaires were collected from 216 patients between March and November 2012. Since the onset of their treatment, 31.4% of the women (68/216) had not been on sick-leave. The main factors associated with the pursuit of professional activity were: considering the availability of their physician to answer questions as unimportant [OR = 18.83 (3.60-98.53); P ≤ 0.05]; considering the diagnosis of cancer as likely to have a weak impact on career perspectives [OR = 4.07 (2.49-6.64); P ≤ 0.05]; not having any children in the household [OR = 3.87 (2.38-6.28); P ≤ 0.05]; being in a managerial position [OR = 3.13 (1.88-5.21); P ≤ 0.05]. Negative predictive factors were: physician mentioning adverse effects of the treatment [OR = 0.31 (0.16-0.58); P ≤ 0.05], and patient rating workload as high [OR = 0.26 (0.15-0.46); P ≤ 0.05]. As a result of advances in therapeutic strategies, more patients will expect healthcare professionals, as well as employers and occupational health societies, to prioritise issues pertaining to the maintenance of professional activities during cancer treatment.

Control of experimental Triatoma infestans populations: effect of pour-on cypermethrin applied to chickens under natural conditions in the Argentinean Chaco region.

Among peridomestic structures, chicken coops are sites of major importance for the domestic ecology of Triatoma infestans (Hemiptera: Reduviidae). The aim of this study was to evaluate in an experimental context the effects of a cypermethrin pour-on formulation applied to chickens on blood intake, moulting and mortality in T. infestans, under the natural climatic conditions of a region endemic for Chagas' disease. Experimental chicken huts were made of bricks and covered with plastic mosquito nets. Ninety fourth-instar nymphs were maintained in each hut. The study used a completely random design in which chickens in the experimental group were treated with a cypermethrin pour-on formulation. Five replicates (= huts) of the experimental and control groups were conducted. The number of live T. infestans, blood intake and moults to fifth-instar stage were recorded at 1, 5, 20, 35 and 45 days after the application of cypermethrin. Cumulative mortality was higher in nymphs exposed to treated chickens (> 71%) than in control nymphs (< 50%) (P < 0.01). Blood intake and moulting rate were lower in nymphs fed on treated chickens than in control nymphs (P < 0.05). Pour-on cypermethrin was able to cause significant mortality, although it did not eliminate the experimental population of T. infestans.

Phylogenetic relationships of the Spinolai complex and other Triatomini based on mitochondrial DNA sequences (Hemiptera: Reduviidae).

In this study, we performed a phylogenetic analysis of 35 species of the tribe Triatomini by means of available 16S ribosomal DNA and cytochrome b (Cyt b) gene sequence data, adding taxa of the spinolai complex, to clarify phylogenetic relationships of this complex and related triatomines. The phylogenetic analysis suggests a monophyletic clustering of the spinolai complex related to the South American species of triatomines.

Deciphering morphology in Triatominae: the evolutionary signals.

Many species of Triatominae show evidence for morphological plasticity. Frequent taxonomic questions arose from this variability leading to disputes about describing new subspecies, species or even genera. We suggest this phenotypic flexibility is primarily an intraspecific feature, but with potential for evolutionary changes. We present arguments for a selection regime leading to the separation of species having low developmental canalization into morphologically distinct ecotypes. We suggest that these ecotypes, or morphs, or forms, may have evolutionary importance even if gene flow still exists between them. Thus, although we consider the morphological plasticity of Triatominae as an intraspecific trait, we defend the idea that it might represent a common evolutionary route to new species. Speciation processes in Triatominae could result from disruptive selection regimes combined with weak developmental canalization. Added to this basic pattern, accidental events could hasten evolutionary change. We suggest the heterosis as one of them.

Phenotypic diversity of Triatoma infestans at the microgeographic level in the Gran Chaco of Argentina and the Andean valleys of Bolivia.

Triatoma infestans (Klug) is the main vector of Trypanosoma cruzi, etiologic agent of Chagas disease. The phenotype of the species varies at different geographic scales. The objective of this study was to compare the antennal phenotype of spatially close T. infestans populations and to evaluate its usefulness as a marker of exchange of individuals between populations. The antennal phenotype of 190 T. infestans from Argentina and Bolivia was analyzed using uni- and multivariate techniques. This study shows heterogeneity of the antennal phenotypes of closely related T. infestans populations living in different habitats. Specimens collected in a goat corral and a rabbit cage in La Rioja (Argentina) were dissimilar to the specimens collected in the nearby intradomestic environment. Similarly, specimens from peridomestic corrals in Cochabamba (Bolivia) were different from the intradomestic and sylvatic specimens, indicating some degree of isolation between these populations. In contrast, T. infestans collected in chicken coops and the intradomestic environment were similar, in all studied regions, suggesting a frequent exchange of individuals between the two habitats and/or because of the similarity of the habitat due to the presence of chickens in the intradomestic environment. We propose that each habitat affects in a particular mode the insect morphology and these changes could be used to identify recolonizing T. infestans. These results support the hypothesis of different degrees of isolation between intradomestic and peridomestic habitats. Within this context, special attention should be given to chicken coops and other close peridomestic structures in relation to the recolonization process of domestic habitats by T. infestans.

[Bursitis due to Mycobacterium intracellulare in an immunocompetent patient]. / Bursite fistulisée à Mycobacterium intracellulare chez un adulte immunocompétent.

BACKGROUND: Cutaneous infections due to Mycobacterium intracellulare are infrequent. We report a case of bursitis in an immunocompetent patient. CASE-REPORT: A 80-year-old patient with a history of tuberculosis reported swelling of the elbow for six months with effusion due to olecranon bursitis, progressing to an abscess and skin ulceration. Examination of the synovial fluid revealed the presence of M. intracellulare. Histologic investigations showed epithelioid and gigantocellular granulations. Screening for immunodepression was negative. Treatment with clarithromycin and rifabutin proved effective, with partial healing at three months, although hepatic and ocular side effects occurred. DISCUSSION: While osteomyelitis, arthritis and cutaneous infections due to M. intracellulare have been described in immunocompromised patients, there are very few reported cases concerning immunocompetent individuals, and these suggest the possibility of special individual sensitivity to mycobacterial infections. Genetic mutations of the interleukin-12-interferon-gamma pathway involved in the immune response to mycobacterial infections have been demonstrated. Autoantibodies against interferon-gamma have also been described. Mycobacterium avium-intracellulare is resistant to the classical antibiotics used in tuberculosis. As in pulmonary infections, antibiotics with proven in vivo and in vitro efficacy must be used, taking into account the antibiogram and potential side effects, particularly for combined clarithromycin and rifabutin. CONCLUSION: This case report emphasizes the benefits of routine mycobacterial investigation of synovial fluid samples.

[Granuloma annulare of the eyelid in a child: an atypical localization]. / Granulome annulaire des paupières: une localisation atypique.

BACKGROUND: Granuloma annulare is a common form of dermatosis in children and young adults. Lesions are typically found on the hands, the feet and the extensor surfaces of the limbs, and occasionally on the trunk. We report a case original in terms of its palpebral localization. CASE-REPORT: A 5 year-old girl consulted for papular lesions on the eyelids. The clinical examination revealed papules on the right lower eyelid measuring 8 mm, on the left lower eyelid measuring 5 mm and on the right upper eyelid measuring 3 mm. Laboratory tests including serum glucose, lipids and calcium as well as a complete blood count proved normal. Biopsy showed granulomatous lesions: a region of central necrosis surrounded by a palisade of inflammatory cells confirmed the diagnosis of granuloma annulare. The lesions disappeared in a few weeks without treatment. DISCUSSION: To our knowledge, 44 cases of granuloma annulare of the periorbital area have been reported, of which 19 concerned children. This presentation represents an atypical localization of granuloma annulare which must not be confused with many other palpebral disorders. Biopsy is necessary to confirm the diagnosis.

Infestation of rural houses by Triatoma infestans in the region of Los Llanos (La Rioja, Argentina).

Vectorial transmission of Chagas disease has been strongly reduced in most parts of the Southern Cone countries of South America, except in the Gran Chaco region of Argentina, Bolivia, and Paraguay. Given periodical interruptions of the vector control programmes in the endemic region of the Gran Chaco of Argentina, the vectorial transmission of the disease has been increasing during the last years. From the beginning of 2004, the provincial Ministry of Health of La Rioja, Argentina, started a vector control programme to cover the rural houses of the Los Llanos area in the southwestern area of the Gran Chaco region. This article reports the result of a standardized entomological survey and insecticide application against Chagas disease vectors in the intra and peridomestic structures of the rural houses of Los Llanos. A total of 4062 houses were inspected, of which 46.8% were found to be infested by Triatoma infestans. Infestation by vector species other than T. infestans was less than 0.5%(T. eratyrusiformis and T. platensis). Intradomestic infestation was found in 27.2%, whereas peridomestic infestation was found in 39.3% of the houses. The lowest figure of intradomestic infestation was 6.6% (Department F Varela), and the highest value of intradomestic infestation was 45.1% (Department Independencia). In spite of the demonstrated success of vector control elsewhere, this study shows that the vector populations are susceptible to pyrethroid insecticides in the southern area of the Gran Chaco of Argentina, that there still are regions where rural houses show heavy infestation by T. infestans associated with big peridomestic structures and that the vectorial transmission of the Chagas disease will continue, unless a sustained and well organized vector control effort is installed in the region.

Infestation of rural houses by Triatoma infestans in the region of Los Llanos (La Rioja, Argentina)

Vectorial transmission of Chagas disease has been strongly reduced in most parts of the Southern Cone countries of South America, except in the Gran Chaco region of Argentina, Bolivia, and Paraguay. Given periodical interruptions of the vector control programmes in the endemic region of the Gran Chaco of Argentina, the vectorial transmission of the disease has been increasing during the last years. From the beginning of 2004, the provincial Ministry of Health of La Rioja, Argentina, started a vector control programme to cover the rural houses of the Los Llanos area in the southwestern area of the Gran Chaco region. This article reports the result of a standardized entomological survey and insecticide application against Chagas disease vectors in the intra and peridomestic structures of the rural houses of Los Llanos. A total of 4062 houses were inspected, of which 46.8 percent were found to be infested by Triatoma infestans. Infestation by vector species other than T. infestans was less than 0.5 percent(T. eratyrusiformis and T. platensis). Intradomestic infestation was found in 27.2 percent, whereas peridomestic infestation was found in 39.3 percent of the houses. The lowest figure of intradomestic infestation was 6.6 percent (Department F Varela), and the highest value of intradomestic infestation was 45.1 percent (Department Independencia). In spite of the demonstrated success of vector control elsewhere, this study shows that the vector populations are susceptible to pyrethroid insecticides in the southern area of the Gran Chaco of Argentina, that there still are regions where rural houses show heavy infestation by T. infestans associated with big peridomestic structures and that the vectorial transmission of the Chagas disease will continue, unless a sustained and well organized vector control effort is installed in the region.

Infestation of rural houses by Triatoma infestans (Hemiptera: Reduviidae) in southern area of Gran Chaco in Argentina.

The impact of control activities against Triatoma infestans (Klug) (Hemiptera: Reduviidae) in South America has a marked contrast within and outside the Gran Chaco region. Development of a geographic information system, as part of an improvement in control program activities, allowed analysis of the spatial pattern of house infestations by T. infestans before and after house spraying with deltamethrin in the San Martin Department (an arid Chaco region of central Argentina). The overall peridomestic infestation index decreased from 48.2 to 28.2% after insecticide application. House infestation was spatially clustered in regions with low or high infestation levels that were located east and southwest of the department, respectively. This pattern was detected both before and after the insecticide application. Three environmental variables calculated from a temporal series of MODIS imagery (average of night temperature, maximum of day temperature, and temporal variation of vegetation index) were capable of correctly discriminating 96% of the places belonging to either high or low house infestation observed after the insecticide application.

Antennal phenotype of Triatoma dimidiata populations and its relationship with species of phyllosoma and protracta complexes.

Triatoma dimidiata (Latreille 1811) Reduviidae Triatominae is the main vector of Chagas disease in several countries of Latin America. As for other vector species, the characterization of T. dimidiata subpopulations within particular geographical regions or occupying different habitats could help in better planning of vector control actions. A first objective in this study was to evaluate the antennal phenotype as a phenetic marker to characterize populations of T. dimidiata collected in different geographic areas and domestic and sylvatic habitats. A second objective was to evaluate the phenetic relationships of T. dimidiata with other species of the phyllosoma complex: longipennis, pallidipennis, and phyllosoma. The antennal sensilla of T. dimidiata specimens collected in Mexico, Central America, and Colombia were analyzed and compared with the antennal sensilla of T. longipennis, T. pallidipennis, and T. phyllosoma. T. barberi was used as an outgroup in the analysis. For each specimen, the ventral side of the three distal segments of the antennae was drawn, identifying and counting four types of sensilla. In T. dimidiata, univariate and multivariate analysis showed differences between sexes, among populations collected in different habitats within the same region, and among populations collected in different geographic regions. Two types of antennal sensilla showed a latitudinal variation. Domestic specimens showed intermediate characteristics of the antennal phenotype, between sylvatic cave- and sylvatic forest-collected specimens. The antennal phenotypes show high similarities among T. pallidipennis, T. phyllosoma, and T. longipennis, with a better differentiation of T. pallidipennis. T. dimidiata is separated from the other members of the complex by a similar distance to T. barberi, of the protracta complex.

Patterns of antenal sensilla of Panstrongylus megistus from three Brazilian states

The objective of the present study was to analyze and describe the phenotype of the antennal sensilla of Panstrongylus megistus, one of the epidemiologically most important species of triatomines in Brazil. Specimens from the Brazilian states of Goiás (GO), Minas Gerais (MG), and Rio Grande do Sul (RS) were compared, based on studies of four types of sensilla on three antennal segments: thick-walled trichoid (TK), thin-walled trichoid (TH), bristles (BR), and basiconica (BA). Discriminant analysis allowed the separation of the RS specimens from those of GO and MG. Multivariate discriminant analysis demonstrated that the sensilla of males differed from those of females, the variables with greatest weight being the BA of all three segments and the TK of flagellum 1. The basiconica sensilla were significantly more abundant in females, on all three segments. Antennal sensilla patterns also demonstrated significant differences among P. megistus specimens.

Patterns of antennal sensilla of Panstrongylus megistus from three Brazilian states.

The objective of the present study was to analyze and describe the phenotype of the antennal sensilla of Panstrongylus megistus, one of the epidemiologically most important species of triatomines in Brazil. Specimens from the Brazilian states of Goiás (GO), Minas Gerais (MG), and Rio Grande do Sul (RS) were compared, based on studies of four types of sensilla on three antennal segments: thick-walled trichoid (TK), thin-walled trichoid (TH), bristles (BR), and basiconica (BA). Discriminant analysis allowed the separation of the RS specimens from those of GO and MG. Multivariate discriminant analysis demonstrated that the sensilla of males differed from those of females, the variables with greatest weight being the BA of all three segments and the TK of flagellum 1. The basiconica sensilla were significantly more abundant in females, on all three segments. Antennal sensilla patterns also demonstrated significant differences among P. megistus specimens.

Changes associated with laboratory rearing in antennal sensilla patterns of Triatoma infestans, Rhodnius prolixus, and Rhodnius pallescens (Hemiptera, Reduviidae, Triatominae).

We examined changes in the array of antennal sensilla of three species of Triatominae (Triatoma infestans, Rhodnius prolixus, and R. pallescens) following their establishment for different periods in laboratory culture. In each case, the laboratory colonies were compared with conspecific samples taken directly from the field, by quantitative analysis of the sensilla arrays on the three distal segments of the antenna in terms of the densities of three types of chemoreceptors (basiconics and thick and thin walled trichoids) and one type of mechanoreceptor (bristles). Sensilla densities were compared by ANOVA or non-parametric tests, and by multivariate discriminant analysis. Strains of the same species reared in different laboratories showed significant differences in their sensilla arrays, especially when compared to field-collected material from the same geographic origin. A Bolivian strain of T. infestans reared in the laboratory for 15 years and fed at monthly intervals, showed greatest differences from its conspecific wild forms, especially in terms of reductions in the number of chemoreceptors. By contrast, an Argentine strain of T. infestans reared for 25 years in the laboratory and fed weekly, showed a relative increase in the density of mechanoreceptors. A Colombian strain of R. prolixus reared for 20 years and fed weekly or fortnightly, showed only modest differences in the sensilla array when compared to its wild populations from the same area. However, a Colombian strain of R. pallescens reared for 12 years and fed fortnightly, did show highly significant reductions in one form of chemoreceptor compared to its conspecific wild populations. For all populations, multivariate analysis clearly discriminated between laboratory and field collected specimens, suggesting that artificial rearing can lead to modifications in the sensory array. This not only supports the idea of morphological plasticity in these species, but also suggests caution in the use of long-established laboratory material for experimental studies designed to extrapolate the natural behaviour and physiology of these species.

Entomological aspects of Chagas' disease transmission in the domestic habitat, Argentina

OBJETIVO: Estudiar el riesgo doméstico de transmisión de Trypanosoma cruzi por medio de un indicador entomológico y analizar su relación con características culturales y de las viviendas. MÉTODOS: Se estudiaron 158 casas en el área endémica argentina. Cada vivienda infestada se clasificó de acuerdo con un indicador entomológico de riesgo (número de picadas riesgosas/ humano). Mediante encuestas se evaluaron factores de riesgo asociados a la vivienda y habitos de los moradores. RESULTADOS: Las casas infestadas mostraron un rango amplio de valores de riesgo (0 a 5 picadas riesgosas/ humano). Se observó un gran número de viviendas con bajos valores de riesgo y pocas viviendas con valores elevados. El 44 por ciento de las Triatoma infestans colectadas estaban alimentadas sobre ser humano y el 27 por ciento sobre perro o gallina. Las viviendas donde perros y/o gallinas compartían la habitación humana, tuvieron valores de riesgo más elevados. Las viviendas ordenadas y limpias exhibieron bajos valores, debido a un escaso número de T. infestans. Se comprobó un 24.3 por ciento de correlación entre el tiempo transcurrido luego de aplicar insecticidas y el número de vectores en la vivienda. Sin embargo, no hubo correlación entre el tiempo post-rociado y la infectividad de T. infestans. Se observó correlación entre los valores del indicador entomológico y la seroprevalencia en niños. CONCLUSIONES: El riesgo de transmisión de T. cruzi en cada vivienda, medido a través de un indicador entomológico, se correlaciona positivamente con la prevalencia de seropositividad en niños y con hábitos de los moradores.

Changes associated with laboratory rearing in antennal sensilla patterns of Triatoma infestans, Rhodnius prolixus, and Rhodnius pallescens (Hemiptera, Reduviidae, Triatominae)

We examined changes in the array of antennal sensilla of three species of Triatominae (Triatoma infestans, Rhodnius prolixus, and R. pallescens) following their establishment for different periods in laboratory culture. In each case, the laboratory colonies were compared with conspecific samples taken directly from the field, by quantitative analysis of the sensilla arrays on the three distal segments of the antenna in terms of the densities of three types of chemoreceptors (basiconics and thick and thin walled trichoids) and one type of mechanoreceptor (bristles). Sensilla densities were compared by ANOVA or non-parametric tests, and by multivariate discriminant analysis. Strains of the same species reared in different laboratories showed significant differences in their sensilla arrays, especially when compared to field-collected material from the same geographic origin. A Bolivian strain of T. infestans reared in the laboratory for 15 years and fed at monthly intervals, showed greatest differences from its conspecific wild forms, especially in terms of reductions in the number of chemoreceptors. By contrast, an Argentine strain of T. infestans reared for 25 years in the laboratory and fed weekly, showed a relative increase in the density of mechanoreceptors. A Colombian strain of R. prolixus reared for 20 years and fed weekly or fortnightly, showed only modest differences in the sensilla array when compared to its wild populations from the same area. However, a Colombian strain of R. pallescens reared for 12 years and fed fortnightly, did show highly significant reductions in one form of chemoreceptor compared to its conspecific wild populations. For all populations, multivariate analysis clearly discriminated between laboratory and field collected specimens, suggesting that artificial rearing can lead to modifications in the sensory array. This not only supports the idea of morphological plasticity in these species, but also suggests caution in the use of long-established laboratory material for experimental studies designed to extrapolate the natural behaviour and physiology of these species.

Relationship between antennal sensilla pattern and habitat in six species of Triatominae

In order to determine if habitat similarity is correlated with a similarity of sensilla pattern, we analyzed six species of Triatominae present in two biogeographic regions of Brazil: the "caatinga" and the "cerrado". In broad terms Triatoma infestans (cerrado) and T. brasiliensis (caatinga) are found in human domiciles, T. sordida (cerrado) and T. pseudomaculata (caatinga) colonize peridomestic habitats, and Rhodnius neglectus (cerrado) and R. nasutus (caatinga) inhabit palm tree crowns. The number and distribution of four sensilla types (bristles, thin and thick walled trichoidea, and basiconica) were compared in these species. Sexual dimorphism of sensilla patterns was noted in T. sordida, T. brasiliensis and T. pseudomaculata. A principal component analysis showed three main groups: (i) species that live in the palms, (ii) domiciliated species and (iii) those living in the peridomestic habitat. T. infestans almost exclusively domestic, was placed at the centre of the canonical map and some individuals of other species overlapped there. These results support the idea that the patterns of antennal sensilla are sensitive indicators of adaptive process in Triatominae. We propose that those species that inhabit less stable habitats possess more types of sensilla on the pedicel, and higher number of antennal sensilla

Relationship between antennal sensilla pattern and habitat in six species of Triatominae.

In order to determine if habitat similarity is correlated with a similarity of sensilla pattern, we analyzed six species of Triatominae present in two biogeographic regions of Brazil: the "caatinga" and the "cerrado". In broad terms Triatoma infestans (cerrado) and T. brasiliensis (caatinga) are found in human domiciles, T. sordida (cerrado) and T. pseudomaculata (caatinga) colonize peridomestic habitats, and Rhodnius neglectus (cerrado) and R. nasutus (caatinga) inhabit palm tree crowns. The number and distribution of four sensilla types (bristles, thin and thick walled trichoidea, and basiconica) were compared in these species. Sexual dimorphism of sensilla patterns was noted in T. sordida, T. brasiliensis and T. pseudomaculata. A principal component analysis showed three main groups: (i) species that live in the palms, (ii) domiciliated species and (iii) those living in the peridomestic habitat. T. infestans almost exclusively domestic, was placed at the centre of the canonical map and some individuals of other species overlapped there. These results support the idea that the patterns of antennal sensilla are sensitive indicators of adaptive process in Triatominae. We propose that those species that inhabit less stable habitats possess more types of sensilla on the pedicel, and higher number of antennal sensilla.