<i>Sciurus stramineus</i>(Rodentia: Sciuridae)

Merrick, Melissa J.; Koprowski, John L.; Gwinn, R. Nathan

doi:10.1644/894.1

Cited by 7 publications

(7 citation statements)

References 17 publications

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“…This shift likely occurred in the dry Andean environments of southwestern Ecuador and northwestern Peru that overall lack native palm populations [ 25 , 26 , 30 , 32 , 39 ]. In Loja, wild R. ecuadoriensis often breed inside the nests of the tree-squirrel, Sciurus stramineus/nebouxii [ 2 , 30 , 32 , 33 , 91 ]. Within nest microhabitats, the close physical proximity between the (virtually ectoparasitic) bugs and their hosts would relax selection for long/narrow heads and mouthparts, which may be required for biting free-ranging hosts more safely (at a longer distance) and sucking their blood faster (thanks to larger cibarial-pump muscles) [ 89 , 92 ].…”

Section: Discussionmentioning

confidence: 99%

Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae

et al. 2021

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Background Triatomine bugs, the vectors of Chagas disease, associate with vertebrate hosts in highly diverse ecotopes. It has been proposed that occupation of new microhabitats may trigger selection for distinct phenotypic variants in these blood-sucking bugs. Although understanding phenotypic variation is key to the study of adaptive evolution and central to phenotype-based taxonomy, the drivers of phenotypic change and diversity in triatomines remain poorly understood. Methods/results We combined a detailed phenotypic appraisal (including morphology and morphometrics) with mitochondrial cytb and nuclear ITS2 DNA sequence analyses to study Rhodnius ecuadoriensis populations from across the species’ range. We found three major, naked-eye phenotypic variants. Southern-Andean bugs primarily from vertebrate-nest microhabitats (Ecuador/Peru) are typical, light-colored, small bugs with short heads/wings. Northern-Andean bugs from wet-forest palms (Ecuador) are dark, large bugs with long heads/wings. Finally, northern-lowland bugs primarily from dry-forest palms (Ecuador) are light-colored and medium-sized. Wing and (size-free) head shapes are similar across Ecuadorian populations, regardless of habitat or phenotype, but distinct in Peruvian bugs. Bayesian phylogenetic and multispecies-coalescent DNA sequence analyses strongly suggest that Ecuadorian and Peruvian populations are two independently evolving lineages, with little within-lineage phylogeographic structuring or differentiation. Conclusions We report sharp naked-eye phenotypic divergence of genetically similar Ecuadorian R. ecuadoriensis (nest-dwelling southern-Andean vs palm-dwelling northern bugs; and palm-dwelling Andean vs lowland), and sharp naked-eye phenotypic similarity of typical, yet genetically distinct, southern-Andean bugs primarily from vertebrate-nest (but not palm) microhabitats. This remarkable phenotypic diversity within a single nominal species likely stems from microhabitat adaptations possibly involving predator-driven selection (yielding substrate-matching camouflage coloration) and a shift from palm-crown to vertebrate-nest microhabitats (yielding smaller bodies and shorter and stouter heads). These findings shed new light on the origins of phenotypic diversity in triatomines, warn against excess reliance on phenotype-based triatomine-bug taxonomy, and confirm the Triatominae as an informative model system for the study of phenotypic change under ecological pressure"Image missing" .

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Section: Discussionmentioning

confidence: 99%

Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae

et al. 2021

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“…This shift likely occurred in the dry Andean environments of southwestern Ecuador-northwestern Peru that overall lack native palm populations [25,26,30,32,39]. In Loja, wild R. ecuadoriensis often breed inside the nests of the tree-squirrel, Sciurus stramineus/nebouxii [2,30,32,33,88]. Within nest microhabitats, the close physical proximity between the (virtually ectoparasitc) bugs and their hosts would relax selection for long/narrow heads and mouthparts, which may be required for biting free-ranging hosts more safely (at a longer distance) and sucking their blood faster (thanks to larger cibarial-pump muscles) [86,89].…”

Section: Phenotypic Variability At the Micro-scale: Microhabitat Adapmentioning

confidence: 99%

Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae

Abad‐Franch

Monteiro

Pavan

et al. 2020

Preprint

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BackgroundTriatomine bugs, the vectors of Chagas disease, associate with vertebrate hosts in highly diverse ecotopes. When these blood-sucking bugs adapt to new microhabitats, their phenotypes may change. Although understanding phenotypic variation is key to the study of adaptive evolution and central to phenotype-based taxonomy, the drivers of phenotypic change and diversity in triatomines remain poorly understood.Methods/FindingsWe combined a detailed phenotypic appraisal (including morphology and morphometrics) with mitochondrial cytb and nuclear ITS2 DNA-sequence analyses to study Rhodnius ecuadoriensis populations from across the species’ range. We found three major, naked-eye phenotypic variants. Southern-Andean bugs (SW Ecuador/NW Peru) from house and vertebrate-nest microhabitats are typical, light-colored, small bugs with short heads/wings. Northern-Andean bugs (W Ecuador wet-forest palms) are dark, large bugs with long heads/wings. Finally, northern-lowland bugs (coastal Ecuador dry-forest palms) are light-colored and medium-sized. Wing and (size-free) head shapes are similar across Ecuadorian populations, regardless of habitat or naked-eye phenotype, but distinct in Peruvian bugs. Bayesian phylogenetic and multispecies-coalescent DNA-sequence analyses strongly suggest that Ecuadorian and Peruvian populations are two independently-evolving lineages, with little within-lineage structuring/differentiation.ConclusionsWe report sharp naked-eye phenotypic divergence of genetically similar Ecuadorian R. ecuadoriensis (house/nest southern-Andean vs. palm-dwelling northern bugs; and palm-dwelling Andean vs. lowland); and sharp naked-eye phenotypic similarity of typical, yet genetically distinct, southern-Andean bugs from house and nest (but not palm) microhabitats (SW Ecuador vs. NW Peru). This remarkable phenotypic diversity within a single nominal species likely stems from microhabitat adaptations possibly involving predator-driven selective pressure (yielding substrate-matching camouflage coloration) and a shift from palm-crown to vertebrate-nest microhabitats (yielding smaller bodies and shorter heads and wings). These findings shed new light on the origins of phenotypic diversity in triatomines, warn against excess reliance on phenotype-based triatomine-bug taxonomy, and confirm the Triatominae as an informative model-system for the study of phenotypic change under ecological pressure.Author summaryTriatomine bugs feed on the blood of vertebrates including humans and transmit the parasite that causes Chagas disease. The bugs, of which 150+ species are known, are highly diverse in size, shape, and color. Some species look so similar that they are commonly confused, whereas a few same-species populations look so different that they were thought to be separate species. Despite the crucial role of naked-eye phenotypes in triatomine-bug identification and classification (which are essential for vector control-surveillance), the origins of this variation remain unclear. Here, we describe a striking case of phenotypic divergence, with genetically similar bugs looking very different from one another, and phenotypic convergence, with bugs from two genetically distinct populations (likely on their way to speciation) looking very similar – and all within a single nominal species, Rhodnius ecuadoriensis. Phenotypically divergent populations occupy different ecological regions (wet vs. dry) and microhabitats (palm-crowns vs. vertebrate nests), whereas convergent populations occupy man-made and nest (but not palm) microhabitats. These findings suggest that triatomines can ‘respond’ to ecological novelty by changing their external, naked-eye phenotypes as they adapt to new microhabitats. We therefore warn that phenotypic traits such as overall size or color may confound triatomine-bug species identification and classification.

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“…We recorded two adult individuals that remained in the study area for at least 33 to 35 months, suggesting longevity longer than three years in the wild. Related species with different body sizes and habitats types frequently live about seven years (Nitikman 1985, Lurz et al 2005, Merrick et al 2012.…”

Section: Mnka (Mean ± Sd)mentioning

confidence: 99%

A 3-YEAR POPULATION STUDY OF Guerlinguetus brasiliensis ingrami (RODENTIA, SCIURIDAE) AT THE SERRA DA BOCAINA NATIONAL PARK, RIO DE JANEIRO STATE, BRAZIL

et al. 2019

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The Brazilian Squirrel Guerlinguetus brasiliensis ingrami (Rodentia, Sciuridae) is commonly observed in the wild, yet its population parameters are poorly known because this species is rarely captured with traditional live-traps. Here we evaluated the population parameters of G. b. ingrami in a 3-year capture-mark-recapture study at the Serra da Bocaina National Park, Rio de Janeiro state, Brazil. Population parameters were evaluated using the Jolly-Seber model POPAN and the Minimum Number Known to be Alive (MNKA). Population size estimates ranged between 3.2 ± 2.4 (mean ± SE) and 51.3 ± 15.0 individuals based on POPAN, and 2 and 10 individuals based on MNKA. Our population density estimates (1.3 to 74.3 individuals/km 2) were similar to those documented in previous studies carried out in the Atlantic Forest. Monthly survival was high (0.94 ± 0.02) and capture probability was low (0.16 ± 0.05), probably reflecting the species trap-shyness. The low capture probability of G. b. ingrami evidences the importance of the unique population data presented in this study for increasing basic knowledge on this species.

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Sciurus stramineus(Rodentia: Sciuridae)

Cited by 7 publications

References 17 publications

Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae

Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae

Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae

A 3-YEAR POPULATION STUDY OF Guerlinguetus brasiliensis ingrami (RODENTIA, SCIURIDAE) AT THE SERRA DA BOCAINA NATIONAL PARK, RIO DE JANEIRO STATE, BRAZIL

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