Papers by Gilbert Barrantes
Evolution & Development, 2019
Large part of the morphological diversity observed across taxa is attributed to the effect of sex... more Large part of the morphological diversity observed across taxa is attributed to the effect of sexual selection; and the static allometry of these structures vary largely from highly positive to negative, depending on their function, and position on the animal's body. In arthropods, information of how sexually selected contact and reaching male structures use during courtship scale on body size is scarce. We tested two complementary hypotheses: the reaching structure hypothesis and the contact‐function hypothesis, in the spider Kukulcania hibernalis. We used the length of the proximal segments of the male pedipalp to test the reaching structure hypothesis, and claw features to test the contact‐function hypothesis. Our results support both hypotheses. Small males have disproportionally longer pedipalps (highly negative allometry) than large males, increasing the probability of small‐bodied males to inseminate even large females. We also found that both distal contact and noncontac...
Journal of Arachnology, 2009
In this paper, we describe the construction and function of the double sheet and tangle web of Ti... more In this paper, we describe the construction and function of the double sheet and tangle web of Tidarren sisyphoides (Walckenaer 1842). Web construction includes several stages: construction of the scaffolding that serves to support the rest of the web; filling in the dome-shaped and horizontal sheets; and construction of the upper tangle. During construction of the scaffolding, the spider descends by a pre-existing thread to the substrate, moves a few centimeters and attaches the dragline, then she ascends by the new thread, doubling the line or attaching it to another thread. The spider fills in the sheet while walking in an irregular pattern under the sheet, and attaching her dragline using either one or both legs IV simultaneously to hold pre-existing sheet lines against her spinnerets. During scaffolding construction and filling in the dome-shaped sheet, the spider returns frequently to the retreat, apparently using the same threads near the retreat each time. Threads of both the dome-shaped sheet and the horizontal sheet have small drops of viscid material. The domeshaped sheet and upper tangle comprise the functional trap of the web, while the horizontal sheet apparently plays only a little role in prey capture.
Journal of Arachnology, 2008
In some spiders features of the webs of early instars may represent features of the ancestor's we... more In some spiders features of the webs of early instars may represent features of the ancestor's web. Some second instar spiderlings (first instar outside of the egg sac) of Tengella radiata (Kulczynski 1909) construct a small sheet web without any type of retreat. In subsequent instars, spiderlings construct webs that consist of a sheet with a small retreat that opens near its center. Webs gradually change as spiderlings growth and webs of 7 th instar spiders are indistinguishable from those of adult females. Spiders only begin to include cribellate threads in their webs during the 7 th instar. The growth of T. radiata is slow during the first three instars, but spiders' sizes increase steadily in the subsequent stages. Legs I of adult males are longer than in females, indicating an allometric growth that occurred mainly during the last molt of males.
Behavioural Processes, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
The Wilson Journal of Ornithology, Mar 22, 2022
ABSTRACT Urban development reduces the abundance of most natural resources for some birds but als... more ABSTRACT Urban development reduces the abundance of most natural resources for some birds but also provides new opportunities for others. One group that is more likely affected by urban development is the cavity-nesting species (primary excavators and cavity-adopters), because the main substrates used for nesting, such as dead trees or dirt banks, are frequently removed for security or aesthetic reasons. However, urban development also provides artificial resources that may be used for some cavity-nesting birds such as wooden posts, poles, pipes, holes in house roofs, or building crevices. How cavity-nesting species use these new artificial resources for nesting is poorly understood. Our goal is to provide information on the use of artificial cavities and artificial substrates in urban and human-altered areas for cavity-nesting birds. We opportunistically collected observations of the use of those cavities and substrates from 2003 to 2019 in Costa Rica and found that 20.2% of the 94 Costa Rican bird species that are known to nest in wooden cavities and 9.5% of the 21 Costa Rican bird species that are known to nest in burrows use artificial cavities or artificial substrates for nesting. Although our observations showed that some species are capable of responding to the reduction of natural substrates or cavities in urban habitats through the use of artificial structures, the reproductive success of these birds is still unknown.
Biological Invasions
Identifying the source population of alien species is important to assess the distribution and po... more Identifying the source population of alien species is important to assess the distribution and potential effects in the invaded area. The araneid spider Cyrtophora citricola is widely distributed in Europe, Asia, and Africa; however, in the last 26 years, it has been reported in several countries across the Americas. To date, the geographic origin of the populations established in the Americas remains unclear, but considering the successful colonization after its recent arrival, assessing climatic similarities between the invaded and native geographic ranges could be useful to address this question. In this study, we used a combination of Species Distribution Models and Ordination Methods to assess the climatic match between 1 digitalcommons.unl.edu
Arachnology
Abstract Behavioural adjustments to changing environmental conditions are advantageous for spider... more Abstract Behavioural adjustments to changing environmental conditions are advantageous for spiders, as such adjustments likely allow spiders to remain in good hunting sites. Here, we describe the behavioural response of seven araneoid species to heavy rain in the neotropics. Five of the seven spiders drastically modified their position on the web, relative to the typical resting position. Four of these species (Allocyclosa bifurca, Argiope argentata, Cyrtophora citricola, and Leucauge mariana) hung from hub threads using their legs III and IV, oriented the anterior section of the prosoma downward, and moved legs I and II forward in front of the spider's eyes. Trichonephila clavipes had a similar response, but hung from only its legs IV. Two other species (Gasteracantha cancriformis and Micrathena duodecimspinosa) did not show an apparent response to heavy rain. The change in position reduces the spider's surface that heavy rain could impact, and speeds water drainage which may reduce pathogen infection.
Arachnology
Function transition used to determine whether the behaviour sequence follows a non-random pattern... more Function transition used to determine whether the behaviour sequence follows a non-random pattern using permutations. This method created nsim random transitions among behavioural units using the observed sequences, then determined the proportion of random transitions where the values were equal or higher than the value of the observed transition. This proportion represents
Revista De Biologia Tropical, 2015
La riqueza avifaunistica en los manglares es relativamente alta contrastando con su pobre diversi... more La riqueza avifaunistica en los manglares es relativamente alta contrastando con su pobre diversidad floristica. Durante 18 meses (julio 1986 a diciembre 1987) visite por ocho dias cada dos semanas un area de manglar de 200 hectareas en Chomes, noroeste de Costa Rica. En estas visitas cuantifique la actividad reproductiva de las especies residentes de este manglar. El 55% de las 69 aves terrestres .residentes se reproducen en el manglar. Probablemente el numero de especies asi como el numero de individuos que se reproducen en este ecosistema se ha incrementado con la destruccion de los bosques originales que cubrian las tierras circundantes. La destruccion de los bosques aledanos asi como la del mismo manglar, incrementa el riesgo de extincion local de aquellas especies que utilizan este ecosistema como su habitat primario, incluyendo a Amazilia boucardi , una especie endemica a los manglares de Costa Rica y cuyo limite norte de distribucion es. precisamente Chomes.
Species-specific life history traits result from the interaction among different factors. In spid... more Species-specific life history traits result from the interaction among different factors. In spiders the clutch size and the size of eggs are expected to be influenced by the female body size, but also by other factors such as accessibility to food resources as well as energy and time invested in maternal care. In eight theridiods the female body size of spiders and the maternal care predict the clutch size. The volume of eggs differs among all species and in general those species with little investment in maternal care and larger body size have larger eggs.
Arachnology, 2021
Most orb weavers orient downward on their orbs, but here we describe an unusual pattern of orient... more Most orb weavers orient downward on their orbs, but here we describe an unusual pattern of orientation in the tetragnathid Azilia guatemalensis. This species changes its orientation on the hub with a consistent day/night pattern. During the day, the spiders orient upward on the orb, but orient downward during the night. In addition, we found that the spiders construct a few silk lines that connect the hub with a sparse mesh near the upper edge of the orb which, in turn, is connected to the substrate. When disturbed, the spider runs using these lines and hides on the substrate, suggesting that its upward orientation during the day, and its escape behaviour, may be a response to diurnal enemies.
The Journal of Arachnology, 2021
The design of orb webs is affected by multiple abiotic (e.g., wind, available space), biotic (e.g... more The design of orb webs is affected by multiple abiotic (e.g., wind, available space), biotic (e.g., prey availability, predation), and species specific (e.g., spider size) factors. Thus, some features of each spider web are expected to reflect the combined effect of such factors. We compared the relationship of spider size and web inclination on the area of different sections of the orb web and other features (e.g., number or radii) between two sympatric Leucauge species (Leucauge sp., and L. argyra (Walckenaer, 1841), Tetragnathidae). Leucauge sp. was smaller and constructed smaller webs across a wider range of inclinations than L. argyra. Other features of the web, e.g., capture area, and hub area, but not the number of adhesive spiral turns and number of radii, were also larger in webs of L. argyra. The inclination was greater in webs of Leucauge sp., but the asymmetry of webs did not differ between species, though, it correlated negatively with the total area of the web of both species, as in other orb-weavers. The characteristics of each species' web suggest that L. argyra optimizes prey interception, while Leucauge sp. optimizes stopping and retention of large prey.
Revista De Biologia Tropical, 2009
The formation of the mountain ranges of Costa Rica and western Panama, as well as the cold climat... more The formation of the mountain ranges of Costa Rica and western Panama, as well as the cold climatic conditions that prevailed during the upper Pleistocene, played a crucial role in determining the bird species composition of the highlands in this region. Glacial conditions favored dispersal movements of bird species from the Andes, and from the Neartic region. Subsequent inter-glacial conditions reduced the connectivity between neotropical highlands (e.g., Talamanca-Andes), and between neotropical highlands and Neartic temper- ate region, isolating recently established populations from the ancestral populations, and promoting speciation. Within Costa Rica, the highland vegetation and the birds that occupied this vegetation possibly had a continuous distribution throughout all mountain ranges during glacial periods. This vegetation retreated to the summit of the mountains during inter-glacial periods, fragmenting the original continuous bird populations and forming "sky islands&...
Revista De Biologia Tropical, 2009
Distribution and density of avifauna in Peninsula de Osa, Costa Rica (1990-1991). We recorded 205... more Distribution and density of avifauna in Peninsula de Osa, Costa Rica (1990-1991). We recorded 205 bird species at the Peninsula de Osa. The geographical distribution of most forest bird species within the peninsula is discontinuous (e.g., Corapipo altera and Tangara guttata), even within large forest tracts, indicat- ing the adaptation of species to particular habitats, microhabitats, strata and/or diet within the forest. Birds use the forest strata in different proportion resulting in three different patterns: understory birds (e.g., Arremon aurantiirostris and Habia atrimaxillaris), supdosel birds (e.g., Cacicus uropygialis and Euphonia imitans), and birds that use several strata in similar proportion (e.g., Dendrocincla anabatina). Most of these forest birds feed upon insects and fruits. The density and relative abundance is very low for most species, with more than 90% of the species having less than an individual per hectare or kilometer of transect. These characteristics make ...
The Wilson Journal of Ornithology, 2021
ABSTRACT The advance of urbanization in Neotropical countries has drastically changed or eliminat... more ABSTRACT The advance of urbanization in Neotropical countries has drastically changed or eliminated extensive areas of natural habitats. Despite these changes, some species breed in cities and adapt to urban conditions. Several variables, such as the type of nest, substrate, and height, as well as the distance to buildings at which nests are constructed, may affect nesting success of birds in urban habitats. Here we tested how these variables affect nest daily survival rate (DSR) of 6 bird species that constructed 3 different types of nests in a high human-density suburb of San José, Costa Rica. The first type includes platform nests built by 3 species of columbids, where at least 1 parent is always present at the nest; the second type includes cup-shaped nests, where both parents can be absent from the nest simultaneously, and is represented by a single species, the Clay-colored Thrush (Turdus grayi); the third type includes closed nests built by 2 species where at least 1 parent is always present. Species with all 3 types of nests display protective behaviors. We quantified nest variables (e.g., type of nest, substrate used to construct the nest, nest height, distance to buildings). The nests differed in their DSR, with a higher nest survival for columbids (3 species; 0.969, SE 0.011), followed by Clay-colored Thrush (0.942, SE 0.009) and closed-nest species (2 species; 0.942, SE 0.028). We found that nesting substrate was the most important variable explaining the DSR in columbids, but none of the variables had a significant effect explaining the DSR in the remaining 2 nest types.
Identifying the source population of invasive species is important to assess the distribution and... more Identifying the source population of invasive species is important to assess the distribution and potential effects in the invaded area. The araneid spider Cyrtophora citricola is widely distributed in Europe, Asia, and Africa; however, in the last twenty years, it has been reported in several countries across the Americas. To date, the geographic origin of the populations established in America remains unclear, but considering the successful colonization after its recent arrival, a high environmental similarity between the invaded and native geographic distributions is expected. In this study, we compared the environmental characteristics of two possible native regions (southern Africa and the Mediterranean) and the invaded region (America), to determine the more likely origin for the populations established in America. We found that the South African populations of C. citricola occupy environments with similar climatic conditions to those of the American populations, and these sim...
Arachnology, 2020
Abstract Many orb-weaving spiders break the central lines of the hub at the end of web constructi... more Abstract Many orb-weaving spiders break the central lines of the hub at the end of web construction. Nevertheless, very little is known of how spiders break these lines and whether this behaviour differs among taxa. Here, we describe details of how Leucauge mariana (Taczanowski, 1981) breaks the central lines of the hub. Breaking hub lines varies among individuals of a single species, and may differ between species.
Journal of Ethology, 2018
The Quarterly Review of Biology, 2017
Bioacoustics, 2017
Duets are highly coordinated acoustical displays produced by two individuals. Studying the struct... more Duets are highly coordinated acoustical displays produced by two individuals. Studying the structure of duet songs and its causes is essential to understand the ecological role and evolution of this form of communication. Our goals in this study were to describe the structure of the duet of the Large-footed Finch, the temporal synchronization of each individual, and to test the effect of provoked (playback) duets. We recorded birds at Cerro de la Muerte, Costa Rica and simulated territory intrusions using playback trials. The duet of this species consisted of overlapping notes between both members of a mated pair, which were emitted either randomly or periodically. Temporal synchronization was similar between both individuals in a mated pair. Both partners adjust the silent intervals between notes in response to the duration of its partner's note. The high frequency of the second part of the duet of this species decreased with time and the second individual, in duetting this part, not only synchronized its notes temporally with the first individual, but also synchronized the high frequency. The high frequency of the first note the second individual sung was a bit lower than the previous note sung by the first individual. Finally, birds responding to provoked duets produced duets with higher frequency and higher rate of notes compared to unprovoked duets. Our results provide information on the temporal and frequency synchronization in duets of an endemic emberizid and provide new information about a less reported vocal behaviour in bird duets, the acoustic frequency coordination.
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Papers by Gilbert Barrantes