Gilbert Barrantes

In adult spiders, leg lengths vary within and between species and is associated with functions in web construction, sensory activities, and prey capture. However, little is known about how leg proportions change during ontogeny. Here we investigate whether leg length relative to body size is maintained throughout development in three cobweb spiders ( Latrodectus geometricus , L. mactans , and Steatoda grossa ). Because spiderlings of these species build webs and capture prey from the first instar, we predicted proportional growth across instars. We also evaluate which model (linear, quadratic, or Gompertz) best describes femur and tibia growth, and estimated growth rates (first derivative) and accelerations (second derivative) for each sex and species. Legs were proportionally shorter in early than in later instars in L. geometricus and S. grossa , whereas proportions remained similar across development in L. mactans . Femur and tibia growth was best described by a quadratic model in both sexes of L. geometricus and L. mactans , and in males of S. grossa . In contrast, females of S. grossa followed a Gompertz trajectory; with high early growth rates that declined toward maturity. Despite these differences in trajectories, leg segments showed similar magnitudes of acceleration within species. Across the three theridiid species, females showed two distinct ontogenetic patterns–steady increases in growth rate (quadratic) or rapid early growth followed by deceleration (Gompertz)–whereas males consistently followed quadratic trajectories. Conserved acceleration among leg segments may reflect developmental canalization that preserves functional proportionality during growth.

Los parches urbanos de vegetación favorecen la conservación de la vida silvestre; no obstante, también plantean una serie de retos. La interacción entre la vida silvestre y los seres humanos es una de los más importantes, pues puede generar conflictos y afectar directamente a ambas partes. La Reserva Ecológica Leonelo Oviedo (RELO) es un parche boscoso urbano localizado en la Ciudad Universitaria Rodrigo Facio de la Universidad de Costa Rica, San José. Es el hábitat de muchas especies de arañas, algunas de las cuales tienen interacciones directas con los seres humanos que hacen uso del espacio y sus alrededores. Las interacciones pueden ser perjudiciales para las arañas debido a diferentes factores sociales que involucran el rechazo humano a estos artrópodos. Con el objetivo de mitigar este problema, se planteó una propuesta de divulgación científica mediante infografías que se ubicaron alrededor de la Reserva Ecológica Leonelo Oviedo, las cuales contenían información relevante sobre la biología, historia natural y comportamiento de varias especies de arañas seleccionadas con el apoyo de un experto y la Red de Áreas Protegidas de la Universidad de Costa Rica (RAP). La propuesta buscó fomentar actitudes neutrales o positivas hacia las arañas que habitan en dicho espacio. Los resultados mostraron opiniones favorables tanto hacia las arañas como hacia las infografías, su contenido y su diseño atractivo. Por tanto, se resalta la importancia de implementar esfuerzos de conservación que involucren la comunicación pública de la ciencia.

Introduction: The taxonomy of Galliformes species, a group closely associated with humans since antiquity, remains unclear at various taxonomic levels, producing taxonomic changes constantly. Objective: Our objective is to provide morphological and acoustic data to support the recent taxonomic recognition of Colinus leucopogon (Spot-bellied Bobwhite) as a distinct species from Colinus cristatus (Crested Bobwhite). Methods: Using a combination of morphological and acoustic analyses, we assessed the differences between these two recently recognized species and compared them with the two other well-established species within the genus: C. nigrogularis (Black-throated Bobwhite) and C. virginianus (Northern Bobwhite). Results: Our acoustic analysis of male songs from 64 individuals showed significant differences in maximum amplitude frequency, song duration, and number of elements, which can act as a reproductive barrier between C. cristatus and C. leucopogon. Morphological analyses, however, revealed only limited differences, primarily in tarsus length and wing chord length. Conclusions: Our findings suggest that while male song characteristics strongly support the recognition of C. cristatus and C. leucopogon as distinct species, morphological differences are less pronounced, potentially due to ecological factors such as habitat similarity and altitudinal distribution. This study highlights the importance of including both acoustic and morphological traits in resolving taxonomic uncertainties and understanding species boundaries in Galliformes.

Introduction: Potalia turbinata (Gentianaceae) is a treelet distributed from Nicaragua to Panama. Information on its reproductive biology and phenology is lacking. Objective: To describe the reproductive phenology of P. turbinata, morphologically characterize its fruits and seeds, and determine whether flower and fruit production correlates with climate (temperature and precipitation) and plant vigor. Methods: The research took place at Tirimbina Biological Reserve in Costa Rica, January 2017–March 2019. Monthly counts of flowers and fruits were conducted on 86 plants. We used circular statistics to determine the duration and peak of flowering and fruiting. Fruit production was compared between years to describe reproductive cycles. We correlated flower and fruit abundance with climatic conditions. Plant measurements included height, basal stem diameter, leaf crop, seeds per fruit, fruit and seed dimensions, and fruit hardness. We used height, diameter, and number of leaves as proxies for plant vigor and compared plant vigor between fruiting (i.e., number of fruits) and non-fruiting plants. Results: Flowering lasted 2–6 months per plant, peaking in April, while fruiting was prolonged (3–10 months), moderately peaking in August. Flower abundance was negatively correlated with precipitation, but fruiting showed no significant correlation with climate. Fruit production negatively correlated with plant height and positively correlated with basal stem diameter. Non-fruiting plants had more leaves than fruiting plants. Conclusions: At the population level, P. turbinata flowered and fruited annually. Individuals were supra-annual, an uncommon reproductive pattern for tropical species. The correlation between flowering and lower precipitation supports possible insect pollination, though direct pollinator observations remain needed. The results concur with other studies indicating a correlation between fruit number and plant size. This investigation provides information on the reproductive phenology and fruit traits of P. turbinata, laying a foundation for future research into its interactions with pollinators and dispersers.

Introduction: The interaction between plants and pollinators is vital for the reproduction of approximately 90% of angiosperms and directly affects ecosystems and agriculture. In tropical regions, 94% of plants require animal pollinators, and in Latin America, 58% of crops depend on pollination by insects. The stability and complexity of plant-pollinator interactions are influenced by several factors, such as floral morphology, which influences nectar accessibility and pollinator specialization. Objective: To compare the diversity and abundance of insect floral visitors in avocado, apple, plum, and blackberry crops in San Gerardo de Dota, Costa Rica. Methods: We systematically collected flower-visiting insects in these crops and identified them taxonomically to the lowest possible level. We then estimated alpha diversity for each crop and compared the community composition (beta diversity) of visiting insects among crops. Results: In 12 sampling visits, we collected a total of 2806 insects from 75 families across all four crops. Alpha diversity was greater in the avocado crop for all three indices (0D, 1D, and 2D). Apis mellifera was the most abundant species in all four crops, but Diptera was the most common group of visiting insects in avocado, particularly flies from the Syrphidae, Muscidae, Calliphoridae, Sarcophagidae, Sciaridae, and Tachinidae families. The insect community of the avocado crop was different from that of the apple, plum, and blackberry crops; however, the insect composition of the other crops was similar. Conclusions: The avocado crop is generalist in terms of floral visitors; this may be attributed to the size of the flower corolla, as flies with short mouthparts usually choose to feed on flowers with small corollas. Flowers of the other crops have similar morphology and are mainly visited by bees. The native entomofauna are abundant on the crop flowers, likely playing an important role as pollinators.

Introduction: Wild plants rely mainly on insects for pollination, and many of these plants are essential to maintaining a diverse and abundant community of crop insect-pollinators. In Costa Rican highland ecosystems, the diversity and abundance of insect floral visitors have been poorly studied, despite their importance and proximity to crops in this area. Objective: to determine the richness and composition of floral visitor insect species of native and ruderal herbaceous plants close to cultivated areas in San Gerardo de Dota, Costa Rica. Methods: We systematically collected flower-visiting insects along transects in two different sites and identified them to the lowest taxonomic level. We estimated alpha diversity for each season and 11 plant groups created specifically for this study. We defined these plant groups based on flower morphology, life history traits, and their taxonomic relatedness. We also compared the insect community composition across seasons and plant groups. Results: We collected a total of 1306 insects, mainly flies (Diptera), from 62 families on 46 plant species during 12 sampling visits. Insect diversity (alpha diversity) increased during the rainy season, possibly because resources (e.g., food and reproductive sites) for flies increase during this season. Insect species composition varied among plant groups. The most abundant insect communities overlapped extensively among plant groups, but other communities compose mainly by some tachinids, chloropids and wasps did not overlap between other plant groups. Conclusion: Seasonal differences in flower-visiting insects could be attributed to a greater availability of resources during the rainy season. Differences in the composition of visitor insects across plant groups were likely influenced by temporal variation in blooming of the different plant groups, blooming intensity, and flower traits. To preserve the rich diversity of floral visitors and the pollination services they provide, a diverse array of ruderal plants must be maintained.

Introduction: The Costa Rican southwestern region is considered one of the neotropical biodiversity hotspots. This geographically isolated forest embraces a rich diversity of moths and butterflies, which is still unknown for the most part. Objectives: (a) Describe and compare the diversity of moths and butterflies among different localities of the southwestern Costa Rican region, and (b) identify information gaps in this group of insects. Methods: Data for this study were collected in 12 different localities by parataxonomists and taxonomists for the national inventory of biodiversity led by INBio (National Biodiversity Institute) using different trap types, but relying mainly on light traps. We compared alpha and beta diversity of moths and butterflies among the six localities (Cortés, Piedras Blancas, Rancho Quemado, Agujas, Los Patos, Sirena) with more extensive sampling. Results: The dataset consisted of 78 747 specimens, of which 2 096 were identified only to the order level. The remaining 76 650 specimens were classified to the family level (n = 48 families), genus, species, or morphospecies. Species and morphospecies were distributed across 37 families. The alpha and beta diversity varied across localities for the 12 families of moths and butterflies that were present in the six localities selected. In general, Piedras Blancas, Rancho Quemado, and Sirena stand out as the most diverse localities. The richness of species varied among different families. For most families Agujas, Los Patos, and Sirena contained more species, but some other families showed a different pattern. Conclusion: Differences in the diversity of moths and butterflies over a northern-southern gradient likely correspond to species (individuals within species) adapted to different biotic (e.g., availability of host plants and food resources) and abiotic (e.g., microclimatic conditions associated to the complex topography of the region) conditions. Despite the large effort made by INBio in knowing and mapping the biodiversity of Costa Rica, and the economic and biological importance of the biodiversity, there are still a huge number of species to be known, named, and properly used.

Introduction: Female fecundity in dioecious plants is influenced by ecological factors that affect pollen and pollinator availability. A high flowering synchrony between sexes, an abundance of pollen donors and pollinators are expected to increase female reproductive success. Objective: To understand how fruit production is related to flowering phenology, sex ratio, abundance and proximity of reproductive males to focal pistillate plants, and pollinator abundance in the dioecious understory palm Chamaedorea pinnatifrons (Arecaceae). Methods: We followed the population flowering of the study species in a montane forest in Costa Rica during 2012. We correlated the number of fruits and fruit set from 115 inflorescences (74 plants) with the size of male and female neighborhoods surrounding focal plants, as well as with plant size and floral display (number of flowers per inflorescence). We estimated pollinator abundance by sampling thrips (Thysanoptera) from staminate inflorescences throughout the plant reproductive season. Results: Flowering was seasonal, with a high degree of overlap between the sexes. The sex ratio of reproductive plants did not significantly deviate from one (79 females and 88 males). Female reproductive success was not related to the abundance and proximity of pollen donors but was instead associated with plants possessing shorter stems, more leaves and flowers per inflorescence, and fewer female neighbors. Late-flowering inflorescences significantly produced more fruits and had a higher fruit set, which coincided with an increase in thrips abundance. Conclusions: We hypothesized that a higher floral display acts as a signal effect to attract pollinators, while larger inflorescences with more flowers can attract more insects, resulting in greater pollination success. Moreover, late-flowering inflorescences seem to benefit from the increase in pollinator abundance at the end of the flowering season. Pollination of C. pinnatifrons and other Chamaedorea species is highly dependent on thrips; as a result, the reproductive success of these palms is susceptible to fluctuations in pollinator population sizes.

Introduction: Urban green spaces are becoming increasingly important refuges for native fauna. In Costa Rica, most of the human population is concentrated in the Central Valley, producing drastic changes in natural ecosystems as urbanization increases and consequently reducing the natural habitats of multiple species. Urban development generally decreases the native diversity of mammals. Objective: We described the richness and abundance of medium-sized terrestrial mammals in fragments of second growth and secondary forest vegetation immersed in an urban matrix. Methods: We conducted a landscape analysis to measure the green spaces and urban land cover, and surveyed terrestrial mammals using night baiting traps, diurnal counts in transects, camera traps, and occasional reports. Results: We found six native and three introduced species of terrestrial mammals, representing less than 50% of the medium-sized mammal diversity reported for the Central Valley of Costa Rica 40 years ago. The common raccoon (Procyon lotor) and the variegated squirrel (Sciurus variegatoides) were the most abundant species, both capable of exploiting urban habitats. Introduced species, especially free-ranging and feral cats (Felis catus), were the most common species in the study site. Free-ranging introduced species may increase predation and disease transmission. Fragmentation, isolation, and lack of connectivity caused by urbanization are likely affect the populations of sloth species (Bradypus variegatus and Choloepus hoffmanni) in the study site. Conclusion: Maintaining natural and seminatural spaces and native vegetation is essential to conserve urban biodiversity.

Introduction: Understanding the factors underlying the interactions among closely related species continue to be an important issue in ecology and evolution. Warblers have been the group model for studying niche partitioning through interspecific competition, without considering other possible factors. A more recent approach includes species-specific morphologies as an important factor that correlates with habitat (or niche) partitioning. Objective: to compare the foraging strategies of five warbler species (Setophaga p. erithachorides, S. petechia, Protonotaria citrea, Parkesia noveboracensis, and Leothlypis peregrina) in a mangrove forest, and to compare the foraging strategies of S. p. erithachorides, the only resident warbler, between periods (presence vs. absence of migrants). Methods: We collected information on substrates and maneuvers used during foraging for the five warbler species during 39 sampling sessions. Each session consisted of recording information for 9 successive days every two weeks. Results: P. noveboracensis differed extensively from the other species in the foraging substrates and maneuvers. The other species formed a more compact group, but some differences in both, substrates and maneuvers, were detected between S. p. erithachorides and L. peregrina. Differences in forging strategies correlate with differences in the morphology among the five warbles species. The foraging strategy of S. p. erithachorides differed between periods. This warbler used the substrates similarly in both periods, but used other maneuvers or change their frequency when migrants are present. Conclusion: differences in the foraging strategy of five warblers can be attributed to a process of morphological and behavioral adaptation to an adaptive scape that includes differences in microhabitat, and biotic interactions (e.g., predation, prey availability) rather than exclusively to interspecific competition.