Elia Ramírez-Arriaga

Botanical characterisation of Mexican honeys from a subtropical region (Oaxaca) based on pollen analysis

Abstract Melissopalynological analysis of 39 honey samples from Oaxaca, Mexico, enabled us to establish the important plant sources exploited by bees during the principal harvest in four districts of the State of Oaxaca, Mexico. A total of 64 taxa belonging to 29 families were recorded. These subtropical honeys were characterised by their botanical origin as follows: (a) monofloral honeys of Bursera simaruba, Clethra mexicana, Cordia alliodora, Lonchocarpus sp., Mangifera indica, Miconia argentea, Orbignya cohune and Quercus sp.; (b) bifloral honeys with an association of Heliocarpus donnell-smithii and Ceiba sp., Lonchocarpus sp. and Mimosa pudica, H. donnell-smithii and Mangifera indica, Miconia argentea and Miconia tenuiflora; (c) oligofloral honeys of Asteraceae; and (d) multifloral honeys with three or four species ≥10%. Monofloral honeys were placed in classes I, II, III, IV and V. Oligofloral were class II, bifloral were classes I and II, and polyfloral honeys were assigned to classes I, II and III. Honey samples of Apis mellifera had a diversity index range of 0.3 to 2.7. It is well known that this bee is polylectic and has a heterogeneous foraging behaviour. In the State of Oaxaca, it prefers resources of secondary vegetation from low deciduous forest, although taxa of economic importance were also utilised, for instance, Mangifera indica and Citrus sinensis. Oaxaca has important and diverse native resources, and beekeeping activity needs to be promoted because of its potential to develop new types of honey.

Foraging of Nannotrigona testaceicornis, Trigona (Tetragonisca) angustula, Scaptotrigona mexicana and Plebeia sp. in the Tacaná region, Chiapas, Mexico

Abstract The sources consumed by Nannotrigona testaceicornis (Na), Trigona (Tetragonisca) angustula (Te), Scaptotrigona mexicana (Sc) and Plebeia sp. (Pl) were studied at two localities in southeast Mexico: Union Juarez (U.J.) and Santa Teresita (S.T.), by means of melissopalynological analyse of pollen, honey and larval food. A total of 246 samples were collected in an annual cycle from April (1987) to March (1988). The analyse showed that these native bees are polylectic. At U.J., 54 species of plants were important and there was an overlap of trophic niches in the four bee species when they collected nectar and pollen from Ageratum houstonianun, Alchornea latifolia, Tremna micrantha, Coffea arabica and Citrus limon. Two bee species foraged at 12 plant taxa, including Iresine celosia (Sc, Te), Vernonia canescens (Sc, Pl), Cercidium praecox (Na, Sc). At S.T. 65 taxa were important with an overlap in (Na, Te, Sc and Pl) at one nectaropolliniferous species: Sapindus saponaria. Three native bees collected a...

Melitopalynological Characterization of Scaptotrigona mexicana Guerin (Apidae: Meliponini) and Apis mellifera L. (Apidae: Apini) Honey Samples in Northern Puebla State, Mexico

Abstract Honey samples belonging to Scaptotrigona mexicana Guérin and Apis mellifera L. from 10 localities in northern Puebla State were evaluated by means of melitopalynologic analysis. Pollen from nine plant taxa had values of importance (≥10%): Ageratum houstonianum Mill. (Compositae), Bursera spp. (Burseraceae), Coffea arabica L. (Rubiaceae), Muntingia cf. M. calabura L. (Tiliaceae), Heliocarpus donnell-smithii Rose (Tiliaceae), Miconia argentea DC. (Melastomataceae), Pimenta dioica (L.) Merr. (Myrtaceae), Quercus sp. (Fagaceae) and Vernonia sp. (Compositae). Honey samples of S. mexicana had relatively high numbers of pollen grains per gram and diversity indexes. Both stingless bee and honey bee samples suggested heterogeneous foraging behavior. In addition, high correlation indexes were registered between honey samples of S. mexicana and A. mellifera. Botanical relationships among S. mexicana (PAE: Parsimony Analysis of Endemism) honey samples were established by A. houstonianum, H. donell-smithii, M. argentea and Piper sp.

Palynological evidence for Middle Miocene vegetation in the Tehuacán Formation of Puebla, Mexico

Palynological assemblages from the Tehuacán Formation (TF), geochronologically dated as Middle Miocene (15.6 ± 0.4 Ma), provide evidence of a highly diverse flora that, at the generic level, is similar to the extant flora in the Tehuacán Valley. We propose that, during Miocene times, plant communities may have been formed of similar botanical elements to those seen today in the region, with some taxa adapted to semiarid conditions. While major temperate floristic elements of Pinus, Quercus, Juniperus, cloud forest and mexical vegetation can be recognized, components of tropical deciduous forests, such as Burseraceae, Leguminosae and Cactaceae, are also present, indicating semiarid conditions. Semiarid local conditions are also inferred from the geological record, consisting of lacustrine and alluvial fan deposits, which contain abundant evaporites beds. This lithology was formed under high evaporation and moderate precipitation conditions, as usually occurs in small basins fed by a seasonal input of water in semiarid environments. Important differences in the vegetation from the TF palynoflora as compared to older associations from south-central Mexico can be inferred, such as an increase in the diversity of semiarid taxa, belonging to Leguminosae and Burseraceae, and the oldest abundant occurrence of the Cactaceae.

Correlation of the Late Eocene–Early Oligocene Izúcar de Matamoros Evaporites (Cuayuca Formation) in Mexico Based on Parsimony Analysis of Endemicity

Abstract Based on the lithology of the Izucar de Matamoros (IzM) sections, and the occurrence of index taxa such as Armeria, Cicatricosisporites dorogensis, Corsinipollenites, Eucommia, Momipites coryloides, Momipites tenuipolus, Mutisiapollis, and Ranuculacidites operculatus, a correlation between the IzM sections and the Cuayuca Formation stratotypes is proposed. The IzM sections are Late Eocene–Early Oligocene, and they are part of the evaporitic member (Mcy) of the Cuayuca Formation. These new data are consistent with the paleoenvironmental interpretations proposed for the formation. It was probably deposited under local xeric conditions in a semiarid climate that allowed the development of grassland (Gramineae with Amaranthaceae–Chenopodiaceae and Ephedra) and a thorn shrub community with Acacia, other Leguminosae, Linum, and Plumbaginaceae. The neighboring communities were probably tropical deciduous forests, low tropical deciduous forest, thorn forest, and chaparral. There were also regional temperate vegetations such as a Picea–Pinus forest, and a cloud forest community. Using parsimony analysis of endemicity, a biogeographic method, a palynofloristic relationship between the Cuayuca Formation and the Pie de Vaca Formation (Late Eocene–Early Oligocene) is proposed. Both formations are within the Balsas Group, and are correlated with San Gregorio Formation (Oligocene) of southern Baja California.

Tertiary Palynofloristic correlations between Mexican Formations with emphasis in dating the Balsas Group

The present work includes a palynofloristic synthesis of Tertiary research carried out at marine and continental basins with particular emphasis on stratigraphy of the Balsas Group sensu Fries (1960). Also it includes palynostratigraphic information related with San Gregorio Formation (Baja California Sur State) and Cuayuca Formation (Puebla State) assemblages. Taxa of chronostratigraphic and ecologic importance are emphasized at every paleobasin. The numerical and cladistic correlation showed that palynological assemblages of units belonging to the Balsas Group are closely related to San Gregorio flora. The results indicate that since the Paleocene, under a tropical regime, an evergreen forest was present together with warm temperate elements. Later, in the Eocene epoch, the tropical floras remained as the principal components of the vegetation. In the Late Eocene - Early Oligocene, the assemblages are a mixture of temperate and desert taxa prevailing over tropical elements at the Sierra Madre Occidental Province. But the subtropical and tropical floras continued as the main components in the Gulf Coast Province where the tropical vegetation stayed up to the Holocene. In contrast, in the western basin localities (Sierra Madre Occidental Province) it was detected a desertification since the Oligocene where savannas and grasses became established. Afterwards, in the Miocene, at the same region, the xerophitic flora dominates the assemblages, proving the existence of a desert at that time.

Comparative study of pollen morphology and exine ultrastructure in tetrads, octads and polyads of the genus Mimosa (Leguminosae)

ABSTRACT This is the first study of exine ultrastructure to be performed in five endemic Mexican Mimosa taxa (M. pringlei var. pringlei, M. calcicola, M. spirocarpa, M. caerulea and M. sousae), one occurring in Mexico and Central America (M. occidentalis), one widely distributed throughout the neotropics (M. setosa var. paludosa), and two in South America (M. irrigua and M. daleoides). Mimosa pollen grains are associated in polyads (12 grains), octads and tetrads. Polyads and octads in members of the basal clade of Mimosa phylogeny (sect. Mimadenia) evince the affinity of Mimosa with Piptadenia. Octads are retained in sect. Batocaulon and tetrads are evolved in this section. More recent clades (sect. Habbasia, Mimosa and Calothamnos) only show tetrads varying in size and shape. Polyads show greater variation in the exine layers, with a bistratified granular structure. Octads display a columellar-granular infratectal structure while tetrads in sect. Mimosa exhibit a less variable exine with a granular infratectal structure.

Angiosperm Resources for Stingless Bees (Apidae, Meliponini): A Pot-Pollen Melittopalynological Study in the Gulf of Mexico

The present work provides melittopalynological knowledge of Melipona beecheii, Plebeia sp. and Scaptotrigona mexicana pot-pollen samples in the states of Campeche and Veracruz along the Gulf of Mexico. These results have been merged with previous angiosperm data sets reported in Mexican pot-pollen melittopalynological studies of Meliponini. Pollen analyses of M. beecheii, Plebeia sp. and S. mexicana pot-pollen samples allowed us to identify polylectic foraging behaviour, as well as temporal or local monolectic and oligolectic specialisation in these stingless bees. M. beecheii in Campeche preferred Solanum verbascifolium from the shrub stratum, as well as Physalis pubescens and S. lanceolatum from the herb stratum. In the state of Veracruz, Plebeia sp. samples from Coatepec contained pollen from Cocos nucifera, Cecropia sp. and Heliocarpus appendiculatus trees, as well as the Coffea arabica shrub and Asteraceae herbs. S. mexicana samples from Huatusco abundantly contained H. appendiculatus and Alchornea latifolia. Finally, in Ixhuacan de los Reyes, S. mexicana pot-pollen samples recorded distinctive cloud forest elements from the tree stratum (Quercus, Liquidambar and Platanus mexicana), and from the shrub stratum, Hedyosmum, Acacia and Ziziphus were recorded. Sustainable meliponiculture in Veracruz has promoted an educational programme named school of meliponiculture, developed for the teaching of proper practices and the utilisation of different products from stingless bee colonies.

A palynological study and molecular analysis of the Desmodium procumbens group (Leguminosae-Papilionoideae) in Mexico

Abstract Desmodium diversity has been mainly classified using fruit characters, and because of variability in these and other characters, the taxonomy has sometimes been problematic and thus, there is a need for clarification and taxonomic reassessments. This is the case for the Desmodium procumbens group, where several infraspecific taxa have been named. The phylogenetic relationships among taxa referred to this group is unknown, and the taxonomic status has been recently revised only for some of the taxa. In this study, pollen morphology and ultrastructure of D. neomexicanum, D. procumbens var. procumbens, D. procumbens var. exiguum, D. procumbens var. longipes and D. procumbens var. transversum, belonging to the Mexican Desmodium procumbens group, were examined using light, phase-contrast, scanning electron and transmission electron microscopy, in order to establish palynological characters that might contribute to a better taxonomic resolution. Pollen grains are tricolporate, radiosymmetric, oblate spheroidal to prolate spheroidal shape, with lalongate endoapertures and rugulate exine with foveolae between rugulae. The exine is tectate with a columellate and/or granulate structure. The absence of a fastigium, features of exine sculpture, a colpus membrane and infrastructure mainly dominated by granules differentiate the pollen grains of the varieties exiguum and transversum from the other taxa studied. Pollen traits and sequence data provide evidence for separating D. neomexicanum from species D. procumbens. In general, the result from the pollen analysis is congruent with results obtained from a preliminary molecular analysis of this group.