Caribbean Lowlands Of Costa Rica Research Articles

A new species of planthopper in the genus Anotia Kirby (Hemiptera: Auchenorrhyncha: Derbidae) from coconut palm in Costa Rica

An ongoing survey for planthoppers associated with palms in the Caribbean basin is being conducted with current efforts on the Caribbean lowlands of Costa Rica. In an expedition in June of 2019, a derbid was found on coconut palms in Alajuela province and was determined to be a new species belonging to the genus Anotia. The novel taxon is described and named Anotia firebugia Bahder Bartlett sp. n. Additionally, molecular barcode data (COI) is provided for the newly described taxon.

Telebasis rojinegra (Odonata: Zygoptera: Coenagrionidae) sp. nov. from Costa Rica

Telebasis rojinegra sp. nov. was recorded from ponds at La Selva Biological Station and three other sites in the Caribbean lowlands of Costa Rica. The new species appears closely related to T. boomsmae Garrison, 1994 recorded from Mexico, Belize and Costa Rica, T. collopistes Calvert, 1902 ranging from Mexico to Honduras, and T. garrisoni Bick Bick, 1995 from South America, but differs in having straighter and more elongate paraprocts and a half black pattern on the rear of the head. The female mesostigmal plates are also distinct from the above species. Telebasis rojinegra was active on the water primarily during afternoon hours.

Two new species of Lepanthes (Orchidaceae: Pleurothallidinae) from Costa Rica and their phylogenetic affinity

Lepanthes is one of the most species-rich genera of angiosperms in the neotropics. Here, we describe and illustrate two new species of Lepanthes from Caribbean lowlands of Costa Rica. Lepanthes crucitasensis,sp. nov. resembles L. confusa, from which it can be distinguished by longer and wider leaves and flowers with entire margin sepals, longer lateral sepals, longer upper lobe and lip with glabrous appendix. Lepanthes adenophorasp.nov. is similar to L. crucitasensis, but it is distinguished by the narrower leaves, always green, shorter inflorescences, pink scarlet petals with a yellow center and with the upper and lower lobe of different lengths, lip not surpassing the column, appendix with glandular trichomes and obovoid-elliptic pollinia. Micromorphologically, the petals of L. adenophora are pubescent or papillose–hispid. Both new species conform a clade closely related to two species from montane forests, suggesting that some lineages can potentially survive or adapt to warmer habitats. Our results demonstrate that alpha-taxonomic studies are pivotal for uncovering phylogenetic relationships in poorly sampled neotropical orchid groups.

Genetic relationships of Caribbean lowland spiny pocket mice (Heteromys desmarestianus: Rodentia; Heteromyidae): evidence of a distinct mitochondrial lineage

Genetic studies provide important insights into the evolutionary history and taxonomy of species, allowing us to identify lineages difficult to distinguish morphologically. The relationship among species in the genus Heteromys has been in flux as new species have been described, and candidate species have been suggested in the H. desmarestianus group. One new potential species may be in Costa Rica’s Caribbean lowlands. Herein, we test the phylogenetic relationship of individuals from Costa Rica’s Caribbean lowlands to individuals from throughout the species’ range using mitochondrial sequences from cytochrome-b (cytb). We captured 116 individuals from the lowlands, sequenced their cytb genes, and incorporated 74 GenBank sequences from throughout the species’ range to test if individuals from Costa Rica’s Caribbean lowlands potentially constitute an undescribed species. Our results document a distinct mitochondrial lineage in the Caribbean lowlands of Costa Rica. Our results from extensive sampling within the lowlands show a unique mitochondrial DNA lineage, which may suggest the presence of an undescribed species. The Caribbean lowlands of Costa Rica may hold other cryptic diversity, and further phylogenetic studies should incorporate samples from this area, as it may have a unique evolutionary history.

Patterns in a species‐rich tropical understory plant community

AbstractUnderstory plants are an important component of the high plant species diversity characteristic of neotropical rain forests. Herbs, shrubs, understory trees, and saplings of canopy trees occupy a broadly uniform environment of abundant rainfall, low light levels, and high humidity. We asked whether this community at the La Selva Biological Station in the Caribbean lowlands of Costa Rica was structured by environmental filters such as soil origin, topographic position, and understory light availability. We used nested quadrats to assess effects of soil origin (recent alluvium, weathered alluvium, residual volcanic soil) and topographic position (ridges, mid‐slopes and flats) on species composition, density, and diversity and measured six edaphic and understory light parameters. Non‐metric multidimensional scaling ordinations were based on frequency of occurrence in 20 quadrats for 272 species in the shrub size class and 136 species in the small‐tree size class for 17 sites. Three axes were correlated with composite environmental variables produced by principal component analysis representing slope, extractable phosphorus, and light. NMS site positions also reflected soil origin, topographic position, and geographic location. The analyses illustrated a complex community structured by species responses to environmental filters at multiple, interdigitated spatial scales. We suggest that light availability affected by canopy dynamics and dispersal limitation provides additional sources of variation in species distributions, which interact with edaphic patterns in complex ways.Abstract in Spanish is available with online material.

Plants and gall hosts of the Tirimbina Biological Reserve, Sarapiqui, Costa Rica: Combining field sampling with herbarium records

There has been an increasing number of inventories of gall-inducing arthropods in the Neotropics. Nonetheless, very few inventories have been carried out in areas where the flora is well documented, and records of galls from herbaria and sites outside the study area have seldom been utilized. In this study we provide a checklist of the native vascular plants of a 345 ha forest reserve in the Caribbean lowlands of Costa Rica and document which of these plants were found to harbor galls. The gall surveys were carried out between November 2013 and December 2016. We also cross-checked our plant list with the previous gall records from elsewhere in the country and searched for galls on herbarium specimens of dicots reported from the reserve. In total, we recorded 143 families and 1174 plant species, of which 401 were hosts of galls. Plant hosts of galls were found in the following non-mutually exclusive categories: 209 in our field sampling, 257 from previous records, and 158 in herbarium specimens. Of our field records of galls, 77 were new for the country, 77 were also found in the herbarium and 110 had been previously recorded in the country. Herbarium specimens and previous records are good indicators of potential gall hosts but around one quarter (40/158) of the gall records in the herbarium were ambiguous as to whether the tissue alteration was a gall or not. Plant family size was related to number of gall hosts, but most dicot families have similar proportions of gall host species. We concluded that more than a third of the native plants in the reserve are gall hosts, but this number increased to 44.93 % when only dicots were considered. Our results demonstrate the utility of providing complete plant inventories when conducting gall inventories, and of using herbarium specimens and previous galls studies to infer gall diversity in a specific area.

Vochysia guatemalensis Donn. Smith, an alternative species for reforestation on acid tropical soils

Vochysia guatemalensis Donn. Smith is a native species commonly used in small-scale reforestation programs in Costa Rica recognized for its fast growth under acidic and unfertile soil conditions. This study aimed to evaluate the nutrient concentration dynamics on individual trees of V. guatemalensis of increasing ages, in order to improve the understanding some aspects of its ecology as well as management of this tree species. Nutrient (N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, and B) and Al concentration in stems, branches and foliage were measured using false time series (also known as chronosequences) in 13 different tree stands (2–21 years) found in the Caribbean lowlands of Costa Rica. N, K and S concentrations in the stems showed a significant inverse relationship with DBH; while P, S, and Cu foliar contents increased with DBH. Average foliar concentrations of N, Ca, K, Mg, Fe, Zn, Mn, B, and Al showed little or no variation with tree growth. Foliar Al concentration (21, 297–28, 826 mg kg−1) was higher than previously reported as toxic for non-Al accumulating species (<1000 mg kg−1), confirming V. guatemalensis as an Al hyper accumulator. Our results reinforce the possibility of using V. guatemalensis for timber production, especially to improve the income of small farmers farming on very acidic soils. The nutrient concentrations that were obtained for different tree components provide baseline information for further studies where the objective is to evaluate the nutritional status of a site.

Asymmetric Response of Costa Rican White-Breasted Wood-Wrens (Henicorhina leucosticta) to Vocalizations from Allopatric Populations.

Divergence in song between allopatric populations can contribute to premating reproductive isolation in territorial birds. Song divergence is typically measured by quantifying divergence in vocal traits using audio recordings, but field playback experiments provide a more direct way to behaviorally measure song divergence between allopatric populations. The White-breasted Wood-Wren (Henicorhina leucosticta; hereafter “WBWW”) is an abundant Neotropical species with four mitochondrial clades (in Central America, the Darién, the Chocó and the Amazon) that are deeply divergent (~5–16% sequence divergence). We assessed the possibility that the WBWW as currently defined may represent multiple biological species by conducting both statistical analysis of vocal characters and field playback experiments within three clades (Central America, Chocó and Amazon). Our analysis of vocal traits revealed that Central American songs overlapped in acoustic space with Chocó songs, indicating vocal similarity between these two populations, but that Central American songs were largely divergent from Amazonian songs. Playback experiments in the Caribbean lowlands of Costa Rica revealed that Central American WBWWs typically responded aggressively to songs from the Chocó population but did not respond to playback of songs from the Amazonian population, echoing the results of the vocal trait analysis. This marked difference in behavioral response demonstrates that the songs of Central American and Amazonian WBWWs (but not Central American and Chocó WBWWs) have diverged sufficiently that Central American WBWWs no longer recognize song from Amazonian WBWWs as a signal to elicit territorial defense. This suggests that significant premating reproductive isolation has evolved between these two populations, at least from the perspective of the Central American population, and is consistent with the possibility that Central American and Amazonian populations represent distinct biological species. We conclude by advocating for the further use of field playback experiments to assess premating reproductive isolation (and species limits) between allopatric songbird populations, a situation where behavioral systematics can answer questions that phylogenetic systematics cannot.

Una nueva especie y un nuevo registro de Drymonia (Gesneriaceae) en Costa Rica

Se describe Drymonia glandulosa Kriebel, una nueva especie que habita en las bajuras del norte de la vertiente caribe de Costa Rica, y se compara con D. conchocalyx. Drymonia mortoniana Wiehler se reconoce como especie válida y representa un nuevo registro en la flora del país.

Season-specific and guild-specific effects of anthropogenic landscape modification on metacommunity structure of tropical bats.

Fragmentation per se due to human land conversion is a landscape-scale phenomenon. Accordingly, assessment of distributional patterns across a suite of potentially connected communities (i.e. metacommunity structure) is an appropriate approach for understanding the effects of landscape modification and complements the plethora of fragmentation studies that have focused on local community structure. To date, metacommunity structure within human-modified landscapes has been assessed with regard to nestedness along species richness gradients. This is problematic because there is little support that species richness gradients are associated with the factors moulding species distributions. More importantly, many alternative patterns are possible, and different patterns may manifest during different seasons and for different guilds because of variation in resource availability and resource requirements of taxa. We determined the best-fit metacommunity structure of a phyllostomid bat assemblage, frugivore ensemble, and gleaning animalivore ensemble within a human-modified landscape in the Caribbean lowlands of Costa Rica during the dry and wet seasons to elucidate important structuring mechanisms. Furthermore, we identified the landscape characteristics associated with the latent gradient underlying metacommunity structure. We discriminated among multiple metacommunity structures by assessing coherence, range turnover, and boundary clumping of an ordinated site-by-species matrix. We identified the landscape characteristics associated with the latent gradient underlying metacommunity structure via hierarchical partitioning. Metacommunity structure was never nested nor structured along a richness gradient. The phyllostomid assemblage and frugivore ensemble exhibited Gleasonian structure (range turnover along a common gradient) during the dry season and Clementsian structure (range turnover and shared boundaries along a common gradient) during the wet season. Distance between forest patches and forest edge density structured the phyllostomid metacommunity during the dry and wet seasons, respectively. Proportion of pasture and forest patch density structured the frugivore metacommunity during the dry season. Gleaning animalivores exhibited chequerboard structure (mutually exclusive species pairs) during the dry season and random structure during the wet season. Metacommunity structure was likely mediated by differential resource use or interspecific relationships. Furthermore, the interaction between landscape characteristics and seasonal variation in resources resulted in season-specific and guild-specific distributional patterns.

Native tree species regulate nitrous oxide fluxes in tropical plantations.

Secondary and managed plantation forests comprise a rapidly increasing portion of the humid tropical forest biome, a region that, in turn, is a major source of nitrous oxide (N2O) emissions to the atmosphere. Previous work has demonstrated reduced N2O emissions in regenerating secondary stands compared to mature forests, yet the importance of species composition in regulating N2O production in young forests remains unclear. We measured N2O fluxes beneath four native tree species planted in replicated, 21-yr-old monodominant stands in the Caribbean lowlands of Costa Rica in comparison with nearby mature forest and abandoned pasture sites at two time points (wetter and drier seasons). We found that species differed eight-fold in their production of N2O, with slower growing, late-successional species (including one legume) promoting high N2O fluxes similar to mature forest, and faster growing, early successional species maintaining low N2O fluxes similar to abandoned pasture. Across all species, N2O flux was positively correlated with soil nitrate concentration in the wetter season and with soil water-filled pore space (WFPS) in the drier season. However, the strongest predictor of N2O fluxes was fine-root growth rate, which was negatively correlated with N2O emissions at both time points. We suggest that tree-specific variation in growth habits creates differences in both N demand and soil water conditions that may exert significant control on N2O fluxes from tropical forests. With the advent of REDD+ and related strategies for fostering climate mitigation via tropical forest regrowth and plantations, we note that species-specific traits as they relate to N2O fluxes may be an important consideration in estimating overall climate benefits.

Group dynamics, behavior, and current and historical abundance of peccaries in Costa Rica's Caribbean lowlands

The abundances and habitat preferences of peccaries in Neotropical forests are important to understand because these keystone species influence many aspects of the ecosystem. In the Caribbean lowlands of Costa Rica, we conducted walking surveys for ~2 years to study the behavior and population trends of collared peccaries (Pecari tajacu), and found that peccaries are abundant at La Selva Biological Station and overall, detection rates were relatively constant through time. A stable estimate of detection rates was achieved only after 7–9 months of surveying. We found no habitat preferences between primary and secondary forest, yet there were some differences in group dynamics—group radius was larger and sighting distance was greater in primary forest, whereas the number of singletons was higher in secondary forest. More peccaries were seen closer to the laboratory clearing than at greater distances, for a variety of probable reasons: habituation to humans, lower predation and hunting pressure, and various environmental and habitat factors. Peccary groups had spatially clumped distributions across the landscape and were more active diurnally than nocturnally. Collared peccary densities are relatively high at La Selva compared to other Neotropical sites, with the exception of Barro Colorado Island. We combined our data with a review of the historical literature to assess changes in the populations of peccaries in the Caribbean lowlands. We found that collared peccaries have likely increased in abundance at La Selva, seemingly a few years after the extirpation of white-lipped peccaries (Tayassu pecari), which were abundant in the area 40–50 years ago. An understanding of the group dynamics, behavior, and habitat preference of collared peccaries is essential for management decisions and conservation efforts. Additionally, assessment of population changes should be carefully considered in a historical context, with a particular focus on how the populations of the 2 peccary species have changed, and how these species might differentially affect their environment.

Food from Earth: Sustainable Farming in Action

With a lurch, the motorized banana tram starts moving slowly along its simple track carrying 100 banana bunches—cornucopias of green fruits, cloaked in blue plastic bags to protect them from insects and sun damage. A Costa Rican worker in a hard hat sits at the helm guiding the tram—nicknamed “the spider”—toward the packing plant a couple miles away. The tram driver and other workers harvested these bananas with machetes on the 813-acre banana plantation at EARTH University (Escuela de Agricultura de la Region Tropical Humeda) in the Caribbean lowlands of Costa Rica.1 The banana is the world’s largest herbaceous flowering plant. Commercial bananas are sterile and are propagated by planting root stock from donor plants (the dark specks in the center of a banana are undeveloped ovules, the precursors to seeds). ... With its row upon row of genetically identical Cavendish banana plants stretching for acres, one might mistake EARTH’s plantation for a traditional banana farm. But through trial, error, and scientific research, EARTH University—funded largely by a U.S. Agency for International Development (USAID) endowment—has created a more ecologically friendly, lower-pesticide (but not organic) banana since the university was established in 1989. The university is also impacting the larger banana industry and nations around the world as alumni take sustainable agriculture initiatives and new business opportunities back to their home countries.

Relación entre la mineralogÍa de la fracción arcilla y la fertilidad en algunos suelos cultivados con banano en las llanuras aluviales del caribe de Costa Rica

Se analizó la relación entre las familias mineralógicas y las características de fertilidad de suelos cultivados con banano en las llanuras del Caribe de Costa Rica. Los resultados corroboran que existen diferencias en fertilidad atribuibles al tipo y cantidad de arcilla dominante, de manera que la CIC, retención de fosfatos y las bases cambiables varían en función de la familia mineralógica. Los suelos agrupados en la familia esmectítica presentaron mayores valores de CIC y bases cambiables y menor retención de fosfatos que los suelos agrupados dentro de la familia metahaloisítica. Los suelos con presencia de vermiculita presentaron menor disponibilidad de K y mayor disponibilidad de Mg.

Fine-root mass, growth and nitrogen content for six tropical tree species

Although fine roots might account for 50% of the annual net primary productivity in moist tropical forests, there are relatively few studies of fine-root dynamics in this biome. We examined fine-root distributions, mass, growth and tissue N and C concentrations for six tree species established in 16-year-old plantations in the Caribbean lowlands of Costa Rica in a randomized-block design (n = 4). The study included five native species (Hyeronima alchorneoides, Pentaclethra macroloba, Virola koschnyi, Vochysia ferruginea and Vochysia guatemalensis) and one exotic (Pinus patula). Under all species >60% of the total fine-root mass to one meter deep was located in the uppermost 15 cm of the soil. Fine-root live biomass and necromass (i.e., the mass of dead fine roots) varied significantly among species but only within the uppermost 15 cm, with biomass values ranging from 182 gm−2 in Pinus to 433 gm−2 in Hyeronima plots, and necromass ranging from 48 gm−2 in Pinus to 183 gm−2 in Virola plots. Root growth, measured using ingrowth cores, differed significantly among species, ranging from 261 gm−2 yr −1 in Pinus to 891 gm−2 yr −1 in Hyeronima. Turnover rates of fine root biomass ranged from 1.09 to 2.03 yr −1 in Virola and Hyeronima plots respectively. Fine-root biomass was significantly and positively correlated with fine-root growth (r = 0.79, P < 0.0001), but did not correlate with fine-root turnover (r = 0.10; P = 0.20), suggesting that fine-root accumulation is a function of growth rate rather than mortality. Fine-root longevity was not correlated (r = 0.20, P = 0.34) and growth was negatively correlated with root N concentration across species (r = -0.78, P < 0.0001), contrary to reported trends for leaves, perhaps because N was relatively abundant at this site.

Natural abundance of 15N in two cacao plantations with legume and non-legume shade trees

Natural abundance of 15N was sampled in young and mature leaves, branches, stem, and coarse roots of trees in a cacao (Theobroma cacao) plantation shaded by legume tree Inga edulis and scattered non-legumes, in a cacao plantation with mixed-species shade (legume Gliricidia sepium and several non-legumes), and in a tree hedgerow bordering the plantations in Guacimo, in the humid Caribbean lowlands of Costa Rica. The deviation of the sample 15N proportion from that of atmosphere (δ15N) was similar in non-legumes Cordia alliodora, Posoqueria latifolia, Rollinia pittieri, and T. cacao. Deep-rooted Hieronyma alchorneoides had lower δ15N than other non-N2-fixers, which probably reflected uptake from a partially different soil N pool. Gliricidia sepium had low δ15N. Inga edulis had high δ15N in leaves and branches but low in stem and coarse roots. The percentage of N fixed from atmosphere out of total tree N (%Nf) in G. sepium varied 56–74%; N2 fixation was more active in July (the rainiest season) than in March (the relatively dry season). The variation of δ15N between organs in I. edulis was probably associated to 15N fractionation in leaves. Stem and coarse root δ15N was assumed to reflect the actual ratio of N2 fixation to soil N uptake; stem-based estimates of %Nf in I. edulis were 48–63%. Theobroma cacao below I. edulis had lower δ15N than T. cacao below mixed-species shade, which may indicate direct N transfer from I. edulis to T. cacao but results so far were inconclusive. Further research should address the 15N fractionation in the studied species for improving the accuracy of the N transfer estimates. The δ15N appeared to vary according to ecophysiological characteristics of the trees.

First Observation of Duetting in the Olive-backed Euphonia (Euphonia gouldi)

Abstract I observed a pair of Olive-backed Euphonias (Euphonia gouldi) in the Caribbean lowlands of Costa Rica singing a prolonged antiphonal duet on 28 February 2006. The male and female were perched near one another within a larger conspecific flock, and exchanged closely-coordinated notes in phrases lasting ∼5 sec. This appears to be the first report of duetting behavior for this species or for any member of family Fringillidae.

Water use in four model tropical plant associations established in the lowlands of Costa Rica

We examined soil water use patterns of four model plant associations established in the North Caribbean lowlands of Costa Rica by comparing the stable hydrogen isotope composition, deltaD, in xylem sap and in soil water at different depths, under rainy and dry conditions. Four 5-year-old model plant associations composed of 2 tree species (Hyeronima alchorneoides and Cedrela odorata) having different architecture and phenology were studied. Average tree height was 8.9 and 7.6 m, respectively. Each tree species was grown in monoculture and in polyculture with 2 perennial monocotyledons (Euterpe oleracea and Heliconia imbricata). Maximum rooting depth at the time of 6D determination was approximately 2 m for almost all species. Most roots of all species were concentrated in the upper soil layers. Stomatal conductance to water vapor (gS) was higher in the deciduous C. odorata than in the evergreen H. alchorneoides; within each species, g, did not differ when the trees were grown in mono or in polyculture. During the rainy season, gradients in soil water 6D were not observed. Average rainy season xylem sap deltaD did not differ among members of the plant combinations tested (-30% per thousand), and was more similar to deltaD values of shallow soil water. Under dry conditions, volumetric soil water content declined from 50 to approximately 35%, and modest gradients in soil water deltaD were observed. Xylem sap deltaD obtained during dry conditions was significantly lower than rainy season values. Xylem sap deltaD of plants growing in the four associations varied between -9 and -22% per hundred, indicating that shallow water was predominantly absorbed during the dry period too. Differences in xylem sap deltaD of trees and monocots were also detected, but no significant patterns emerged. The results suggest that: (a) the plant associations examined extracted water predominantly from shallow soil layers (<1 m), (b) the natural isotopic variation in soil and plant water at the study site was low, and (c) the plant mixes obtain water from more than a single soil layer simultaneously. Temporal factors were important in determining the competition and complementary relations observed among the trees and the perennial monocots. Under the prevailing environmental conditions, water use in these plant associations was determined largely by species-specific attributes such as biomass allocation to fine roots, phenology, and canopy architecture, and to a lesser extent by water limitations.

Soil organic carbon pool under native tree plantations in the Caribbean lowlands of Costa Rica

We evaluated the soil organic carbon (SOC) pool and selected physico-chemical soil variables in a plantation with native tree species established in a degraded pasture of the Caribbean lowlands of Costa Rica. Studies on the rate and accumulation of aboveground biomass and C have been conducted in native tree plantations of Costa Rica. However, more studies on the SOC pool are needed since only few works provide information on the subject. The tree plantation was established in 1991 on a 2.6 ha. degraded pasture ( Ischaemum sp.) Four species were selected: Vochysia guatemalensis Smith, Calophyllum brasiliense Cambess, Stryphnodendron excelsum Poeppig et Endl. and Hieronyma alchorneoides Allemao. Average SOC concentration ranged from 44.9 to 55.2 g kg −1 (0–10 cm), and decreased with depth up to 12.7–16.8 g kg −1 (40–50 cm). The highest SOC pool was measured under H. alchorneoides and V. guatemalensis, i.e. 131.9 and 119.2 Mg C ha −1, respectively, whereas in the pasture it was 115.6 Mg C ha −1. The SOC pool has not changed significantly under the tree species evaluated 14 years after establishment. A multivariate ordination technique named between-within class principal component analysis was used to determine the factors and trend that explain the variability in the data. The effect of vegetation in the SOC and selected soil variables measured in this study was only detected for H. alchorneoides. The information presented herein about the depth distribution of the SOC fraction improves our knowledge for further developing prediction models.

Orb-weaving Spider,Argiope savignyi(Araneidae), Predation on the Proboscis BatRhynchonycterisnaso(Emballonuridae)

We report an observation of an orb- weaving spider (Argiope savignyi; Araneidae) cap- turing and feeding on a proboscis bat (Rhynchonyc- teris naso; Emballonuridae) at the La Selva Biological Station in the Caribbean lowlands of Costa Rica. This observation and others suggest that spiders prey upon small bats more frequently than has been noted previously, and that invertebrates should now be considered as regular predators on small bats.