An increased number of individuals of a potential host facilitates non-photic synchronisation in the haematophagous insect Triatoma infestans

BACKGROUND Triatoma infestans (Kissing bug) is the main vector of the parasite causative of Chagas disease in Latin-America. This species shows clear activity rhythms easily synchronised to day-night cycles (photic cycle). The haematophagous nature of these insects lead us to think that they may temporally adapt to the particular activity rhythms of potential hosts (non-photic cycle). Our previous data showed that kissing bugs were weakly affected by the activity-inactivity rhythm of a single host. OBJETIVE To determine if by increasing the number of individuals of a potential host, T. infestans could increase the likelihood of synchronisation. METHODS Individual activity rhythms of experimental insects, maintained in constant darkness in light-tight cabinets, localised in a room with 24 rodents, were continuously monitored. Another insect group that served as control was maintained in the same conditions but in a room without rodents. FINDINGS Most of the experimental insects synchronised, expressing a 24 h period coincident with the activity-inactivity rhythms of the rodents, while the controls free ran with a period significantly longer than 24 h. CONCLUSION Analogous to what happens with high vs low light intensity in photic synchronisers, a high number of rodents, in contrast to the previous one-rodent experiment, increased the potency of this non-photic zeitgeber.

First report of Rhodnius montenegrensis (Hemiptera: Reduviidae: Triatominae) in Bolivia

ABSTRACT Background: The subfamily Triatominae, which comprises 157 species, carries the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. This short communication reports for the first time the occurrence of Rhodnius montenegrensis in Bolivia. Methods: Active searches were carried out on palm trees of the genus Oenocarpus in Beni district, Bolivia. Results: Fifteen R. montenegrensis specimens were collected from a rural area of the Beni district, Bolivia, and tested positive for T. cruzi. Conclusions: This new report expands the geographic distribution of the species in Latin America. Due to their ability to transmit trypanosomatids, the species deserves the attention of vector control programs.

First report of Microtriatoma borbai Lent & Wygodzinsky, 1979 (Hemiptera, Reduviidae, Triatominae) in the state of Espírito Santo, Brazil: would M. borbai be living in eucalyptus crops?

Abstract INTRODUCTION: The occurrence of Microtriatoma borbai in the state of Espírito Santo, Brazil is reported by the first time. METHODS: A triatomine specimen collected in a hybrid eucalyptus crop in the municipality of Aracruz, Espírito Santo state was found to be a male M. borbai. RESULTS: This finding expands the geographical distribution of M. borbai from four to five Brazilian states. It is the first report of M. borbai occurrence inside a eucalyptus crop. CONCLUSIONS: The occurrence of M. borbai in the state of Espírito Santo broadens the geographical distribution of this species in southeastern Brazil.

Psammolestes tertius Lent & Jurberg, 1965 (Hemiptera, Reduviidae, Triatominae): first report in Sergipe State, Brazil

Abstract INTRODUCTION: This study reports the first occurrence of Psammolestes tertius (Hemiptera, Reduviidae, Triatominae) in the state of Sergipe, Brazil. METHODS: In 2020, 95 specimens were collected from the municipality of Porto da Folha, Sergipe, Brazil. RESULTS: This finding expands the geographical distribution of the species from 15 states in Brazil to 16 and increases the biodiversity of triatomines in the state of Sergipe. CONCLUSIONS: The presence of P. tertius in the state of Sergipe demonstrated a wider distribution of this species in northeastern Brazil.

First report of Microtriatoma borbai Lent & Wygodzinsky, 1979 (Hemiptera, Reduviidae, Triatominae) in the state of Espírito Santo, Brazil: would M. borbai be living in eucalyptus crops?

Abstract INTRODUCTION: The occurrence of Microtriatoma borbai in the state of Espírito Santo, Brazil is reported by the first time. METHODS: A triatomine specimen collected in a hybrid eucalyptus crop in the municipality of Aracruz, Espírito Santo state was found to be a male M. borbai. RESULTS: This finding expands the geographical distribution of M. borbai from four to five Brazilian states. It is the first report of M. borbai occurrence inside a eucalyptus crop. CONCLUSIONS: The occurrence of M. borbai in the state of Espírito Santo broadens the geographical distribution of this species in southeastern Brazil.

Large-scale patterns in morphological diversity and species assemblages in Neotropical Triatominae (Heteroptera: Reduviidae)

We analysed the spatial variation in morphological diversity (MDiv) and species richness (SR) for 91 species of Neotropical Triatominae to determine the ecological relationships between SR and MDiv and to explore the roles that climate, productivity, environmental heterogeneity and the presence of biomes and rivers may play in the structuring of species assemblages. For each 110 km x 110 km-cell on a grid map of America, we determined the number of species (SR) and estimated the mean Gower index (MDiv) based on 12 morphological attributes. We performed bootstrapping analyses of species assemblages to identify whether those assemblages were more similar or dissimilar in their morphology than expected by chance. We applied a multi-model selection procedure and spatial explicit analyses to account for the association of diversity-environment relationships. MDiv and SR both showed a latitudinal gradient, although each peaked at different locations and were thus not strictly spatially congruent. SR decreased with temperature variability and MDiv increased with mean temperature, suggesting a predominant role for ambient energy in determining Triatominae diversity. Species that were more similar than expected by chance co-occurred near the limits of the Triatominae distribution in association with changes in environmental variables. Environmental filtering may underlie the structuring of species assemblages near their distributional limits.