Panamanian Populations Research Articles

Thief workers and variation in nestmate recognition behavior in a ponerine ant, Ectatomma ruidum

Our findings give new insight into the relationship between nestmate recognition and cleptobiosis, intraspecific thievery of newly collected food items, in a neotropical ponerine ant, Ectatomma ruidum. The expression of discrimination of nestmates from non-nestmates varied among local aggregations of E. ruidum in a population at Barro Colorado Island, Panama. This result is due to differences in the behavior of the guard ants among aggregations, rather than differences in the expression of recognition cues by ants. Baiting experiments show that E. ruidum colonies in Panama have a greater tendency to have overlapping home ranges than a similar population in Costa Rica. The pattern of cleptobiosis, however, is strikingly similar between the Panamanian and Costa Rican populations.

The breeding structure of a tropical keystone plant resource

Despite the recognized importance of maintaining viable populations of keystone plant resources in tropical wildlife parks and forested preserves, the critical question of what constitutes effective breeding units of these species has not been directly addressed. Here we use paternity analysis techniques to reconstruct the genotypes of pollen donor trees and to estimate pollen dispersal distances and breeding population size parameters for Panamanian populations of seven species of monoecious strangler figs (Ficus, Moraceae), a particularly widespread and influential group of keystone producers1,2,3. Despite the minute size (1–2 mm) and short lifespan (2–3 d) of the species-specific wasp pollinators (Agaonidae, Chalcidoidea), pollen dispersal was estimated to occur routinely over distances of 5.8–14.2 km between widely spaced host trees. As a result of such extensive pollen movement, breeding units of figs comprise hundreds of intermating individuals distributed over areas of 106–632 km2, an order of magnitude larger than has been documented for any other plant species. Moreover, these results should be generalizable to the 350 or so monoecious fig species that share this pollination system4. The large areal extent of breeding units of these keystone plant resources has important implications for our understanding of both the evolution of tropical biodiversity and its maintenance by applied conservation efforts.

Cytological and Nomenclatural Notes on the Mesoamerican Species of Aciotis (Melastomataceae)

A review of the Mesoamerican species of Aciotis is presented to facilitate the transfer of Spennera alata, an earlier name for the largely Central American species heretofore known as A. levyana. Original chromosome counts of n = 30 are reported for two species, A. alata and A. rostellata, together with brief descriptions, distributional notes, and a regional key to the three Mesoamerican species. Based on a preliminary evaluation of reported chromosome counts, x = 10 appears to be the probable base chromosome number of Aciotis. Aciotis is one of about 30 capsular-fruited genera of the tribe Melastomeae (incl. Tibouchineae) restricted to the Neotropics. This natural genus of herbs and subshrubs is readily distinguished by its small 4-merous flowers borne in terminal panicles, terete hypanthia, eight unappendaged stamens, bilocular ovary, and reniform-cochleate seeds with a foveolate or costate-foveolate testa. Because macromorphological differences among the approximately 30 recognized species (Mathies, 1981) are not always as sharp or as consistent as those encountered in other neotropical genera of the tribe, Aciotis has the reputation of being a taxonomically difficult genus (Wurdack, 1973). Recently, Mathies (1981) contributed to an evaluation of species limits, but the genus is still in need of a thorough field-oriented revisionary study. Despite taxonomic difficulties, identity of the three described species of Aciotis from the Mesoamerican region has not been a major source of confusion. However, examination of type specimens and verification of the identity of taxonomic synonyms pertinent to a treatment of the genus for Flora Mesoamericana has brought to light the need for a new combination that has heretofore been overlooked. Spennera alata, therefore, is transferred here to Aciotis and a synopsis of the three Mesoamerican species is provided together with a key, original meiotic chromosome counts for two of the taxa, and a discussion of the probable base chromosome number of the genus. CHROMOSOME NUMBERS OF ACIOTIS Gametic chromosome numbers are reported here for two populations each of A. alata and A. rostellata. Meiosis was regular with n = 30 in all cells examined from each of these populations. Bud material for these counts was collected from natural populations in the field, fixed in modified Carnoy's solution (4 chloroform, 3 ethanol, 1 glacial acetic acid, v/v/v) for 24 hours, transferred to 70% ethanol, and stored under refrigeration. All counts were made using a Zeiss light microscope with phase contrast and a 100x oil immersion objective. Drawings of meiotic figures were made with camera lucida at a magnification of 2100x. Voucher collections for each of the counts reported here are as follows: Aciotis alata (Beurling) Almeda. n = 30 (Figs. 1, 2). Costa Rica. Lim6n: Forest Reserve at Agricultural College of the Humid Tropical Region ca. 11 km NE of the Guapiles/Lim6n Hwy. at a point 20 km SE of Guapiles, 250 m, 11 Feb. 1992, Almeda et al. 6953 (CAS, CR). Panama. Panami: Cerro Jefe, along summit road and along trail into the Chagres valley, 900 m, 19 Feb. 1988, Almeda et al. 5836 (CAS, PMA). Aciotis rostellata (Naudin) Triana. n = 30 (Figs. 3, 4). Panama. Cocl6: beyond La Mesa on road to the base of Cerro Gaital, 900-1100 m, 23 Feb. 1988, Almeda et al. 5884A (CAS, PMA). Panama. Cocl6: slopes above El Cop6 along abandoned trail to Continental Divide, 700-850 m, 24 Jan. 1989, Almeda et al. 6379 (CAS, PMA). The chromosome count of n = 30 reported here for two Panamanian populations of A. rostellata confirms an identical report for a Costa Rican population of this species by Solt and Wurdack (1980). This same gametic number, which is also reported here for Costa Rican and Panamanian populations of A. alata, is a new number for this species. Solt and Wurdack (1980) reported 2n = 24 for this species (as A. levyana) from Costa Rican seedling maNovoN 7: 333-337. 1997. This content downloaded from 207.46.13.147 on Fri, 20 May 2016 07:56:51 UTC All use subject to http://about.jstor.org/terms

Species boundaries, specialization, and the radiation of sponge-dwelling alpheid shrimp

Microevolutionary studies and natural history suggest that host-specialization has promoted the high diversity of tropical sponge-dwelling snapping shrimps (Decapoda, Alpheidae, Synalpheus). Yet the taxonomic difficulty of this genus has precluded rigorous tests of this hypothesis. S. rathbunae Coutiére is among the most abundant invertebrates inhabiting the framework of sponges and dead coral that forms the floor of Caribbean coral reefs. Even within a small area S. rathbunae exhibits the apparently wide variation in size, color, and morphology that has long frustrated efforts to identify and define species boundaries within this large (< 100 described species) genus. Here I show that sympatric populations of this nominal species occupying different sponge hosts display clear, concordant differences in allozyme genotypes and in multivariate morphometries, confirming that the populations represent three distinct biological species. Moreover, careful field sampling revealed that the three S. rathbunce taxa and the closely related S. filidigitus Armstrong showed almost no overlap in the species of hosts occupied. Interestingly, while there was significant differentiation between Belizean and Panamanian populations of the one taxon that occurred at both sites (∼1500 km apart), these populations were recognizable as conspecific using both genetic and morphological characters. These results show that (1) diversity of Synalpheus, which is already among the most species-rich crustacean genera, is probably several times higher than currendy recognized, and (2) species of sponge-dwelling Synalpheus are highly host-specific, with related species distinctly segregated among hosts. Together with previous evidence of host race differentiation within shrimp species, these results suggest a primary role for resource specialization in the origin and/or maintenance of this group's characteristically high diversity.

Larval development ofClibanarius antillensisStimpson, 1859 (Crustacea: Anomura: Diogenidae) reared under laboratory conditions: a comparison between Panamanian and Brazilian populations

The larval developmental sequences of Clibanarius antillensis Stimpson from first zoea through to megalopa are compared between laboratory-reared populations from Panama and Brazil. Only four zoeal stages are recorded for the Panamanian population, in contrast to four or five for the Brazilian larvae. Other differences in morphology are discussed and illustrated. Variations resulting from geographic differences and/or differing laboratory conditions raise the question of the validity of phylogenetic hypotheses based on single laboratory rearing events.

Population genetics of eight species of Trapezia (Brachyura: Xanthidae), symbionts of corals

Starch-gel electrophoresis was used to study gene-enzyme variation in thirteen populations of eight species of the genus Trapezia from Hawaii, Panama, and Enewetak Atoll (Marshall Islands). Between 20 and 30 (mean = 27.8) gene-enzyme systems were resolved in each population, with 20 systems in common among all populations. The distribution of electrophenotypes was in agreement with Hardy-Weinberg-Castle expectations, except for T. digitalis, which consistently showed heterozygote deficiencies. Diagnostic loci among color forms support the hypothesis that color forms are distinct species. Low values of genetic distance among species suggest a recent radiation, perhaps during the Pleistocene. Genetic distance between the Hawaiian and Panamanian populations of T. ferruginea did not significantly differ from zero, indicating that the Eastern Pacific population of T. ferruginea has recently immigrated from the central Pacific, and/or that there is gene flow between the two areas. There were diagnostic loci between T. ferruginea and T. formosa from Enewetak and the populations of these species from Hawaii (T. ferruginea only) and Panama (both species). Therefore, these geographic populations may represent separate species. The level and pattern of genetic variability in Trapezia spp. are in agreement with those observed in most other organisms.

Breeding Habits of the Toad Bufo coccifer in Costa Rica, with a Description of the Tadpole

-The breeding habits of Bufo coccifer were studied in northwestern Costa Rica between 1971 and 1974. This species breeds during the rainy season, at least from May through August. Males chorus from areas of shallow water. Their calls resemble those of Mexican representatives of the species in pulse rate and duration, but are closer to those of other Costa Rican and Panamanian populations in dominant frequency. Thus, our data do not clearly support recognition of Bufo cycladen as a distinct species for the Mexican populations. Amplexus is axillary, and two strings of eggs are extruded simultaneously during oviposition. Tadpoles, described for the first time in this paper, are secretive and do not aggregate. Development to metamorphosis requires about 5 weeks. Bufo coccifer Cope is a medium sized toad known from localities primarily along the Pacific versant of Mexico and Central America from sea level to about 2000 m elevation (Zweifel, 1965; Porter, 1964a, 1965; Meyer and Wilson, 1971). The mating calls of the Mexican and Central American populations of Bufo coccifer differ (Zweifel, 1965; Porter, 1965). These vocal characteristics, together with slight morphological differences, were used to justify recognition of the Mexican populations as a distinct species, Bufo cycladen (Lynch and Smith, 1966). Porter (1967) argued that Bufo cycladen was a nomen dubium. Although Smith and Smith (1976) recognized the distinctness of the Mexican populations, little information has been published on the species in the past 15 years. The tadpole has not been described. During the course of our work on the reproductive ecology and behavior of frogs in the Tropical Dry Forest formation of northwestern Costa Rica, we obtained considerable data on the breeding biology of Bufo coccifer. Herein, we report our observations and describe the tadpole of this species. STUDY SITE.-The study area was located on the property of Estaci6n Experimental Enrique Jimenez Nufiez in Guanacaste Province, Costa Rica. This station, owned and operated by the Ministerio de Agricultura y Ganaderia of Costa Rica lies about 13.6 km SW Canfas in a zone of Tropical Dry Forest (Tosi, 1969). General site descriptions of the area exist (e.g., Orians and Paulson, 1969; Holdridge et al., 1971; Sawyer and Lindsey, 1971; Janzen, 1973; McDiarmid et al., 1977). However, these papers refer primarily to the forested regions of the farm, particularly those in riparian areas. Although individual Bufo coccifer occasionally are found in forest habitats, these toads are located more commonly in areas where the forest has been cleared for pasture or cultivation. Observations were made in two types of cleared areas. One was a pasture about 2.4 by 1.0 km located at the base of Cerro Eskameca and adjacent hills (Fig. 1). The somewhat irregular pasture (ca. 10 m elev.) is sown with various introduced forage grasses and supports small weedy herbs (e.g., Compositae, Malvaceae, Euphorbiaceae), vines (e.g., Cucurbitaceae, Leguminosae, Bignoniaceae), small saplings of various forest trees (especially Enterolobium cyclocarpum), and a number of leguminous shrubs. One of the shrubs, Mimosa pigra, grew in dense stands covering large areas. Usually, toward the end of each dry season, the pasture areas were plowed and all surface vegetation was turned under. With the first rains, new grass sprouted, and cattle and horses were turned out to graze. Within the pasture areas three ponds filled in May or June and, except in E SOUTHWESTERN ATURALIST 26(4):353-363 NOVEMBER 20, 1981 This content downloaded from 157.55.39.224 on Wed, 14 Dec 2016 05:03:07 UTC All use subject to http://about.jstor.org/terms The Southwestern Naturalist FIG. 1.-Irrigation canal (above), flooded pasture (middle), and flooded roadside (below) at Estaci6n Experimental Enrique Jimenez Nuiiez, used as breeding sites by Bufo coccifer. 'LI IIIWI L C-lC1----I 354 vol. 26, no. 4 -....,-'' .,. __M ._liB36 . ^ This content downloaded from 157.55.39.224 on Wed, 14 Dec 2016 05:03:07 UTC All use subject to http://about.jstor.org/terms McDiarmid and Foster-Costa Rican Bufo coccifer

Antigenic subtypes of hepatitis B antigen in Panama.

Three hundred eighty hepatitis B antigen-positive sera were tested for the a, d, and y antigenic determinants using absorbed human antibody in a counterelectrophoresis test. These sera represented 341 persons from various Panamanian populations. All 69 American Indians tested carried subtype ad, as did most other presumed carriers identified in population surveys (35/38). Most acute sporadic hepatitis patients (103/127) also had the ad subtype. A subset of the sera from asymptomatic Indian and nonIndian carriers and from acute hepatitis patients was tested for the w and r specificities and only w was found.

Differences in the prevalence of hepatitis B antigen and antibody among Panamanian Indian populations.

Counterelectrophoresis was used for testing of 1,623 sera from individuals from Panama's three major Indian tribes for hepatitis B antigen (HB Ag). A random subsample from each group was tested for antibody to HB Ag (HB Ab) by the radioimmunoprecipitation technique. HB Ag was significantly more prevalent among the Guaymi than among either Choco or Cuna Indians, but prevalence of both HB Ag and HB Ab among the Guaymi varied by village. The Chocó had a greater frequency of HB Ab in every age group than the Guaymi, indicating that although Chocó were more intensively exposed to HB Ag than Guaymi, fewer became chronically antigenemic. Using the prevalences of HB Ag and HB Ab, we calculated the percentage of infected individuals who remained chronically antigenemic and found it to be significantly higher among younger people.