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At least 199 records · Page 11Linked to original sources
PubMed1994

FLIGHT PHYSIOLOGY OF NEOTROPICAL BUTTERFLIES: ALLOMETRY OF AIRSPEEDS DURING NATURAL FREE FLIGHT

Airspeed measurements during natural free flight were made on a total of 270 neotropical butterflies representing 62 species. Morphological data were obtained from the same individuals for which airspeeds had been determined. Flight speed was positively correlated with body mass, thoracic mass and wing loading. Controlling for body mass, higher wing loadings were correlated with increased flight speed. Flight speed and wing aspect ratio were negatively correlated. No consistent correlations were found between airspeed and wing length, wing area or body length. Released butterflies and butterflies encountered in natural free flight did not differ substantially in flight speed allometry. The observed scaling of flight speeds was similar to that derived for a much smaller sample of butterflies flying in an insectary, although absolute values of flight speed were approximately three times higher in natural flight and correlation coefficients of allometric regressions were typically lower. These results suggest that butterfly airspeeds under natural conditions can reasonably be predicted from morphological measurements, and that studying flight in enclosed spaces preserves the allometry of flight speeds.

Journal Article↗
PubMed2000

Branchial receptors and cardiorespiratory reflexes in a neotropical fish, the tambaqui (Colossoma macropomum).

This study examined the location and physiological roles of branchial chemoreceptors involved in the cardiorespiratory responses to hypoxia and hypercarbia in a neotropical fish that exhibits aquatic surface respiration, the tambaqui (Colossoma macropomum). Fish were exposed to abrupt progressive environmental hypoxia (18. 6-1.3 kPa water P(O2)) and hypercarbia (water equilibrated with 5 % CO(2) in air, which lowered the water pH from 7.0 to 5.0). They were also subjected to injections of NaCN into the ventral aorta (to stimulate receptors monitoring the blood) and buccal cavity (to stimulate receptors monitoring the respiratory water). All tests were performed before and after selective denervation of branchial branches of cranial nerves IX and X to the gill arches. The data suggest that the O(2) receptors eliciting reflex bradycardia and increases in breathing frequency are situated on all gill arches and sense changes in both the blood and respiratory water and that the O(2) receptors triggering the elevation in systemic vascular resistance, breathing amplitude, swelling of the inferior lip and that induce aquatic surface respiration during hypoxia are extrabranchial, although branchial receptors also contribute to the latter two responses. Hypercarbia also produced bradycardia and increases in breathing frequency, as well as hypertension, and, while the data suggest that there may be receptors uniquely sensitive to changes in CO(2)/pH involved in cardiorespiratory control, this is based on quantitative rather than qualitative differences in receptor responses. These data reveal yet another novel combination for the distribution of cardiorespiratory chemoreceptors in fish from which teleologically satisfying trends have yet to emerge.

Animals↗
PubMed1992

Husbandry, reproduction and postnatal development of the neotropical muroid rodent Zygodontomys brevicauda.

Laboratory colonies of the Neotropical muroid rodent Zygodontomys brevicauda have been employed in studies of arbovirus epidemiology and are currently the subjects of experimental research on tropical mammalian reproductive physiology and evolutionary quantitative genetics. Captive-bred litters typically consist of 4 or 5 pups weighing 3-4 g each at birth. Adults 20-40 weeks old average 60-80 g with some sexual dimorphism. Females are sexually mature at 3-4 weeks of age, males at 6-8 weeks. Ovulation is spontaneous and gestation is 25 days. Preliminary observations are provided on the microbiological status and parasites of captive-bred animals.

Animal Husbandry↗
PubMed2000

Neotropical Monogenoidea 37. Redescription of Gyrodactylus superbus (Szidat, 1973) comb. n. and description of two new species of Gyrodactylus (Gyrodactylidea: Gyrodactylidae) from Corydoras paleatus and C. ehrhardti (Teleostei: Siluriformes: Callichthyidae) of Southern Brazil.

Two new species of Gyrodactylus (Gyrodactylidae) are described from Corydoras paleatus (Jenyns) and Corydoras ehrhardti Steindachner (Callichthyidae) of Rio Piraquara, Municipality of Piraquara, near Curitiba, Paraná, Brazil: Gyrodactylus anisopharynx sp. n. and Gyrodactylus samirae sp. n. These species are unique among the known Neotropical species of Gyrodactylus by the combination of several characters. Gyrodactylus anisopharynx is characterised by having hooks with point evenly curved, toe moderately pointed, round convex heel, straight sloping shelf, superficial bar with anterolateral projections and male copulatory organ armed with two rows of spinelets. Two variants of G. anisopharynx, of distinct pharynx size, are recognised: forma "large-pharynx" and forma "small-pharynx". Gyrodactylus samirae is characterised by having hook with straight shaft, short slightly recurved point, truncate toe, trapezoidal heel, shelf slightly concave, orthogonal to shaft; anchors with relatively short superficial root; superficial bar with extremities lightly expanded; and male copulatory organ armed with two rows of spinelets. Paragyrodactyloides superbus (Szidat, 1973) is redescribed and transferred to Gyrodactylus based on examination of type and new specimens. Features previously considered as diagnostic for the genus are misinterpretations or primitive characters for Gyrodactylus spp.

Animals↗
PubMed1996

[Distribution of Biomphalaria straminae in the southern neotropical region of Brazil].

A careful anatomical revision of 10,616 preserved specimens of snails from 76 localities of the State of S. Paulo, Brazil, was made with a view better to determining the geographical distribution of Biomphalaria straminea in the Neotropical Region of Southern Brazil. The analysis has shown that previous determinations were correct. The study was then complemented with a survey of information from the literature about distribution of the species. The distribution pattern of the species has expanded greatly over the last few years, perhaps an account of the construction of new dams, and the navigation system in the upper Paraná Basin. Epidemiological data have shown that B. straminea is a good host to S. mansoni. Continuous schistosomiasis control must be exercised so as to prevent the further expansion of the disease.

Animals↗
PubMed2005

Isolation of a fragment homologous to the rp49 constitutive gene of Drosophila in the Neotropical malaria vector Anopheles aquasalis (Diptera: Culicidae).

The constitutive ribosomal gene rp49 is frequently used as an endogenous control in Drosophila gene expression experiments. Using the degenerate primer PCR technique we have cloned a fragment homologous to this gene in Anopheles aquasalis Curry, a Neotropical vector of malaria. In addition, based on this first sequence, a new primer was designed, which allowed the isolation of fragments of rp49 in two other species, Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say, suggesting that it could be used to clone fragments of this gene in a number of other mosquito species. Primers were also designed to specifically amplify rp49 cDNA fragments in An. aquasalis and Ae. aegypti, showing that rp49 could be used as a good constitutive control in gene expression studies of these and other vectorially important mosquito species.

Aedes↗
PubMed2002

Distribution, survivorship and mortality sources in immature stages of the neotropical leaf miner Pachyschelus coeruleipennis Kerremans (Coleoptera: Buprestidae).

Distribution, sources of mortality, and survivorship of immatures was investigated during the reproductive season of the neotropical buprestid leaf miner, Pachyschelus coeruleipennis, that burrows in leaves of Croton floribundus (Euphorbiaceae) in SE, Brazil. Immature distribution was investigated by a random sample of 120 shrubs of C. floribundus growing along forest edges. Marked leaves were followed to recorded sources of mortality and survivorship of immature stages. Females lay their eggs preferentially in the young leaves of the host plant, with mines and pupal cells having been found on the middle part of plants. Densities of eggs, active mines, and pupal cells were, respectively, 25 +/- 2, 6 +/- 1, and 1 +/- 0.3 per 100 leaves. Predators and parasitoids accounted for the majority of losses in the immature P. coeruleipennis population. Mortality was 3 times lower in the egg stage than in the last larval instar. Predation rate was greater than parasitism but the latter increased much more during the development of immatures. Survivorship and sources of mortality were different between early and late season sample of leaf-miner immatures. Parasitism rate was greater in the late-season whereas predation was greater in early-season samples. These results are compared with mortality patterns described for other buprestid leaf miners in temperate and tropical regions.

Animals↗
PubMed2005

An illustrated key to adult males of neotropical Fannia Robineau-Desvoidy belonging to pusio sub-group (Diptera, Fanniidae).

The 11 neotropical species of Fannia belonging to the pusio sub-group (canicularis group), are keyed F. dodgei Seago; F. femoralis (Stein); F. pamplonae Couri & Araújo; F. parafemoralis Araújo & Couri; F. paraisensis Araújo & Couri; F. punctivervis Malloch; F. pusio (Wiedemann); F. sabroskyi Seago; F. snyderi Seago; F. trimaculata (Stein); F. trimaculatoides Couri & Pamplona. The key is addressed only to the males and the illustrations help in the visualization of the characters.

Animals↗
PubMed2001

Glypthelmins poncedeleoni n. sp. (Trematoda: Macroderoididae) of amphibians from the neotropical region of México.

A new species of Glypthelmins (Trematoda: Macroderoididae) is described from the intestine of Bufo marinus and Leptodactylus melanonotus from several localities of the Neotropical Region of Mexico. Glypthelmins poncedeleoni n. sp. can be differentiated from other species of the genus by having extracecally distributed vitellaria, ovary always larger than testes, and vitelline follicles grouped in 7 post-testicular, nonoverlapping, rosette-like clusters and 5 pretesticular overlapping clusters.

Animals↗
PubMed2003

Taxonomic revision of Rhinebothroides (Eucestoda: Tetraphyllidea: Phyllobothriidae), parasites of neotropical freshwater stingrays (Rajiformes: Myliobatoidei: Potamotrygonidae).

Extensive new collections of specimens of Rhinebothroides spp. from a wide range of Neotropical freshwater potamotrygonid stingrays in numerous localities permitted critical evaluation of the validity of the 7 nominal species in the genus. Some qualitative characters previously used in the taxonomy of this group are highly variable within and among populations, and most morphometric and meristic characters thought to have taxonomic value for this group overlapped among several previously defined nominal species. Characters that were consistent throughout populations and that clearly define morphotypes supported recognition of 4 species: R. freitasi (syn. R. circularisi and R. venezuelensis), R. glandularis (syn. R. mclennanae), R. moralaurai, and R. scorzai. We provide a taxonomic review of the genus, 8 additional host records, 7 new localities, and an identification key.

Animals↗
PubMed2004

Erroneous reports of the neotropical Echinococcus oligarthrus as a cause of echinococcosis in India.

Two cases of submandibular echinococcosis have been reported in adult residents of India (Kini et al., 1997; Sahni et al., 2000). It was stated in both publications that the cestode was E. oligarthrus, "a rare variety of E. granulosus", based on morphogical characteristics. It was also mentioned that 3 cases of E. granulosus with similar submandibular metacestode had been previously diagnosed in India. The metacestode is readily distinguishable from that of E. oligarthrus. The final hosts of E. oligarthrus are several neotropical species of wild cats and metacestode occurs in hystricognath, all of them absent in India. The larval stage of all 4 species of Echinococcus can be differentiated on the basis of the form and dimensions of rostellar hooks of protoescoleces. With the information provided in the two papers we concluded that the 2 cases of echinococcosis described in India were due to E. granulosus.

Animals↗
PubMed2004

Auriculostoma astyanace n. gen., n. sp. (Digenea: Allocreadiidae), from the banded astyanax, Astyanax fasciatus (Characiformes: Characidae), from Nicaragua, with a reevaluation of neotropical Crepidostomum spp.

Auriculostoma n. gen. (Trematoda: Allocreadiidae) is proposed for Auriculostoma astyanace n. sp. from the intestine of the characid fish Astyanax fasciatus in the Atlantic coastal drainages of Nicaragua. The new genus differs from all papillose allocreadiid genera, except Bunoderella, in possessing 2 pairs of muscular oral papillae (instead of 1 or 3), of which the ventrolateral pair is moderately developed and the dorsolateral papillae are long and auricular. Auriculostoma differs from Bunoderella Schell, 1964, in having lateral vitelline follicles, completely separated or confluent only in the posttesticular region, a uterus limited to the pretesticular region or with a few eggs at the level of the testes, and a long cirrus sac that overlaps the acetabulum or usually reaches posteriorly to the ovarian level. Three other allocreadiid species, all from South American freshwater fishes and each of which had previously been placed in Crepidostomum, are transferred to Auriculostoma based on the presence of the diagnostic muscular oral papillae. These include Crepidostomum platense Szidat, 1954, C. macrorchis Szidat, 1954, and C. stenopteri Mañé-Garzón and Gascón, 1973. Diagnostic features for Auriculostoma also include mainly pretesticular uterus, lateral vitellaria with variation in posttesticular confluence, and tandem testes. The genus appears to be typically associated with neotropical siluriforms (catfishes) and characiforms (tetras).

Animals↗
PubMed2005

Phylogeny of species of Sciadicleithrum (Monogenoidea: Ancyrocephalinae), and their historical biogeography in the neotropics.

The phylogenetic relationships and historical biogeography of species of Sciadicleithrum parasitizing Neotropical cichlid fishes were studied. Hypotheses were: Did the presence of Sciadicleithrum species in southeast Mexico (SM) and Central America (CA) result from early dispersal of cichlid species from South America (SA) to the north via the Antilles during the Tertiary (24 million years ago [mya]), or did it occur after emergence of the Panama Isthmus in the Pleistocene (2-5 mya)? The Sciadicleithrum phylogeny was based on 19 morphological transformation series, with species of Gussevia and Cichlidogyrus as outgroups. The most parsimonious cladogram had a 40% consistency index, with one clade including all the species of Sciadicleithrum from SA and all but one of those from CA and another with all the Sciadicleithrum species from SM and S. maculicaudae from CA. Results support the late dispersal hypothesis following emergence of the Panama Isthmus. Fifteen species of Sciadicleithrum parasitize 13 cichlid species from SA and CA. In contrast, only 4 species of Sciadicleithrum infect 14 cichlid species from SM. Parasite speciation appears to lag behind host speciation, with 2 equally possible explanations: loss of parasite species and host switching.

Animals↗
PubMed2006

Blood parasites of Nearctic-Neotropical migrant passerine birds during spring trans-Gulf migration: impact on host body condition.

To test the hypothesis that migrants infected with blood parasites arrive on the northern coast of the Gulf of Mexico in poorer condition than uninfected birds, we examined 1705 migrant passerine birds representing 54 species of 11 families from 2 Gulf Coast sites for blood parasites. Three hundred and sixty (21.1%) were infected with 1 or more species of 4 genera of blood parasites. The prevalence of parasites was as follows: Haemoproteus spp. (11.7%), Plasmodium spp. (6.7%), Leucocytozoon spp. (1.3%), and Trypanosoma spp. (1.2%). Both prevalence and density of Haemoproteus spp. infection varied among species. We found no relationship of gender or age with the prevalence of Haemoproteus spp. infection or Plasmodium spp. infection, with the exception of the orchard oriole (Icterus spurius) for which older birds were more likely to be infected with Haemoproteus spp. than younger birds. We also found that scarlet tanagers and summer tanagers infected with species of Haemoproteus have lower fat scores than uninfected individuals and that rose-breasted grosbeaks and Baltimore orioles infected with Haemoproteus spp. have a smaller mean body mass than uninfected individuals. Blood parasites do seem to pose a physiological cost for Neotropical migrant passerines and may be important components of the ecology of these species.

Adipose Tissue↗
PubMed2006

The phylogenetic structure of a neotropical forest tree community.

Numerous ecological and evolutionary processes are thought to play a role in maintaining the high plant species diversity of tropical forests. An understanding of the phylogenetic structure of an ecological community can provide insights into the relative importance of different processes structuring that community. The objectives of this study were to measure the phylogenetic structure of Neotropical forest tree communities in the Forest Dynamics Plot (FDP) on Barro Colorado Island, Panama, to determine how the phylogenetic structure of tree communities varied among spatial scales and habitats within the FDP, and to study the effects of null-model choice on estimates of community phylogenetic structure. We measured community phylogenetic structure for tree species occurring together in quadrats ranging in size from 10 x 10 m to 100 X 100 m in the FDP. We estimated phylogenetic structure by comparing observed phylogenetic distances among species to the distribution of phylogenetic distances for null communities generated using two different null models. A null model that did not maintain observed species occurrence frequencies tended to find nonrandom community phylogenetic structure, even for random data. Using a null model that maintained observed species frequencies in null communities, the average phylogenetic structure of tree communities in the FDP was close to random at all spatial scales examined, but more quadrats than expected contained species that were phylogenetically clustered or overdispersed, and phylogenetic structure varied among habitats. In young forests and plateau habitats, communities were phylogenetically clustered, meaning that trees were more closely related to their neighbors than expected, while communities in swamp and slope habitats were phylogenetically overdispersed, meaning that trees were more distantly related to their neighbors than expected. Phylogenetic clustering suggests the importance of environmental filtering of phylogenetically conserved traits in young forests and plateau habitats, but the phylogenetic overdispersion observed in other habitats has several possible explanations, including variation in the strength of ecological processes among habitats or the phylogenetic history of niches, traits, and habitat associations. Future studies will need to include information on species traits in order to explain the variation in phylogenetic structure among habitats in tropical forests.

Ecosystem↗
PubMed2002

Quantitative analysis of gametic incompatibility between closely related species of neotropical sea urchins.

Species of the sea urchin genus Echinometra found on the two coasts of Panamá are recently diverged and only partially isolated by incomplete barriers to interspecific fertilization. This study confirms previous work that revealed incompatibility between the eggs of the Atlantic E. lucunter and the sperm of the other two neotropical species, whereas eggs of its sympatric congener E. viridis and allopatric E. vanbrunti are largely compatible with heterospecific sperm. Here we quantify fertilization using a range of sperm dilutions. We demonstrate a much stronger block to cross-species fertilization of E. lucunter eggs than was previously shown at fixed sperm concentrations, and mild incompatibility of the other two species' eggs where previous crosses between species were not distinguishable from within-species controls. Additionally, we present evidence for intraspecific variation in egg receptivity towards heterospecific sperm. Our findings here again discount the "reinforcement model" as a viable explanation for the pattern of prezygotic isolation. Gamete incompatibility in these Echinometra has appeared recently-within the last 1.5 million years-but is weaker in sympatry than in allopatry. Accidents of history may help explain why incompatibility of eggs emerged in one species and not in others. Compensatory sexual selection on sperm in this species could follow, and promote divergence of proteins mediating sperm-egg recognition.

Animals↗
PubMedDate not supplied

The biology and taxonomy of rust fungi associated with the neotropical vine Mikania micrantha, a major invasive weed in Asia.

Three microcyclic rust species were collected during surveys of the perennial asteraceous vine Mikania micrantha (Eupatorieae: Asteraceae) throughout its native range in the Neotropics but were absent in its invasive range in Asia. The commonest species, Puccinia spegazzinii with brown telioid telia, occurred wherever M. micrantha was found in South and Central America including the Caribbean island of Trinidad. Dietelia portoricensis, with occasional vestigial spermogonia and grayish-white to pale yellow columnar aecioid telia, was collected only in Costa Rica; while D. mesoamericana sp. nov., apparently restricted to Mesoamerica, can be distinguished by its abundant, yellowish-orange, fertile spermogonia, yellow to pale brown telial columns, larger teliospores, and 4-spored rather than 2-spored metabasidia. The fact that all three species share a fundamentally similar symptomatology suggests a common origin.

Asia↗