Pollen Collectors and Other Insect Visitors to \u3ci\u3ePenstemon haydenii\u3c/i\u3e S. Wats.

Records of insects visiting the flowers of Penstemon haydenii (S. Wats.) are supplied. The flower-visitor fauna was different at the two sites censused. Primary pollinators appeared to be four species of megachilid bees which consistently visited the flowers for pollen. While bees exhibited high fidelity to flowers of the genus Penstemon, analysis of the pollen carried by females suggests that crossing over between Penstemon species on a particular foraging trip may be common. Opportunities for interspecific hybridization almost certainly occur

Sella turcica and craniofacial morphology in patients with palatally displaced canines: a retrospective study

Background: The aim of the study was to evaluate the sella and craniofacial morphological features in growing patients with palatally displaced canines compared to controls. Materials and methods: Twenty-two subjects with palatally displaced canines were retrospectively selected and compared to 22 controls matched for age and gender. Lateral cephalograms were collected and sagittal and vertical cephalometric variables were measured, together with sella interclinoid distance, sella depth, and sella diameter. The independent samples T-test or Mann-Whitney U-test were used to compare all the variables between the two groups. A Pearson correlation was computed for the craniofacial and sella variables that differed significantly (p < 0.05) between the groups. Results: Patients with palatally displaced canines showed a smaller interclinoid distance and a greater SNA angle than control subjects. The interclinoid distance and the SNA angle were negatively correlated (–0.52, p = 0.017) in the experimental group. Conclusions: Growing patients with palatally displaced canines had smaller sella interclinoid distances and a greater SNA angle than control subjects

Temporal variation in pollination services to Cucurbita moschata is determined by bee gender and diversity

It has been proposed that species-rich insect communities and species turnover across landscapes enhance the pollination efficiency of crops through complementarity, where both the dominant and less abundant species contribute to reaching a yield threshold from pollination. Alternatively, fluctuations in the most abundant pollinator species, rather than changes in species richness, may drive temporal variation in pollination services. In this study, we used Cucurbita moschata as a model to investigate temporal variation in pollinator communities in a Mexican tropical dry forest region. We sampled floral visitors in the coastal region of Jalisco during the wet and dry seasons and determined the pollination efficiency of all floral visitors. Our results showed that there was temporal variation in the pollinator community and in the pollination efficiency of the main pollinators of Cucurbita moschata crops. In the wet season, native bees of the genus Peponapis were the most frequent and effective pollinators of C. moschata, whereas in the dry season, Peponapis bees were scarce and Apis mellifera became the most frequent floral visitor. Apis mellifera transfers smaller pollen loads than Peponapis, but it provides an effective pollination service in conjunction with other native bees during the dry season. There was also an interaction between flower gender and pollinator species, where A. mellifera had higher visitation rate to female C. moschata flowers, and Peponapis bees to staminate flowers. Mean visitation rate by Peponapis female bees was 17 times higher than visitation rate by male bees. This is the first report of a vis-à-vis relationship of pollinator gender with respect to plant gender in which plants of the genus Cucurbita that produce unisexual staminate and pistillate flowers are differentially visited by Peponapis male and female bees, where females are the main pollinators. Understanding the temporal variation in pollinator communities and the contribution of the different species of pollinators to the reproductive success of different crop species and varieties can be crucial to maintaining pollination services under the current global pollination crisis.Fil: Delgado-Carrillo, Oliverio. Laboratorio Nacional de Análisis y Síntesis Ecológica; México. Universidad Nacional Autónoma de México; MéxicoFil: Martén-Rodríguez, Silvana. Laboratorio Nacional de Análisis y Síntesis Ecológica; MéxicoFil: Ashworth, Lorena. Laboratorio Nacional de Análisis y Síntesis Ecológica; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Aguilar, Ramiro. Laboratorio Nacional de Análisis y Síntesis Ecológica; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Lopezaraiza-Mikel, Martha. Universidad Autonoma de Guerrero; MéxicoFil: Quesada, Mauricio. Laboratorio Nacional de Análisis y Síntesis Ecológica; Méxic

Egg retention and dispersal activity in the parasitoid wasp, Trichogramma principium

Effects of egg retention on movement and dispersal activity of Trichogramma principium (Hymenoptera, Trichogrammatidae) females were investigated under laboratory conditions. Individual females were observed during one minute in the absence of hosts. Movement activity and dispersal rate were estimated by the length of the track and by the distance from the start point, respectively. Before the test, all wasps during 2 – 4 days were presented with a possibility to parasitize a factitious laboratory host, Sitotroga cerealella Oliv. (Lepidoptera, Gelechiidae). Wasps that had parasitized before the test show significant reduction of spontaneous walking activity and dispersal rate when compared with females that refused to parasitize the non-preferred host (i.e. manifested egg retention). This effect cannot be considered as a direct arrestment reaction to the host because during the test period, no hosts were provided. Thus, egg retention results not only in temporal spread, but also in more intensive spatial dispersal of a group of simultaneously emerged females

Alternation of Sex Ratio in a Partially Bivoltine Bee.,\u3ci\u3e Megachile rotundata\u3c/i\u3e (Hymenoptera: Megachilidae)

Data on offspring production by the alfalfa leafcutting bee, Megachile rotundata (F.), from three site-years were used to examine predictions of parental investment and sex ratio theory. In northern Utah, spring-emergent adults produce two types of offspring: those that develop directly to the adult stage and emerge in midsummer, and those that develop to the prepupal stage and enter diapause until the following year. For species with this kind of life cycle, it has been hypothesized that spring parents should bias their investment in summer emergent progeny towards females if spring males survive to participate in the summer mating. Results from all site-years support the theory. The sex ratio of summer-emergent progeny is always biased towards females, that of diapausing progeny is usually biased towards males, and there is always a significant difference between the two; and there is no difference in the sex ratio of diapausing offspring, whether produced by the spring or summer generations. However, the main premise of the theory remains unsubstantiated: in a preliminary estimate, we found the probability that spring males participate in summer matings to be very low. The import of the unexpected finding that diapausing progeny are 50% larger than summer-emergent progeny is discussed

BEE VISITATION OF PHLOX-BRYOIDES POLEMONIACEAE

Volume: 39Start Page: 197End Page: 19