Nesting Behavior, Phenology, and Bionomics of the High Andean Leaf-Cutter Bee Megachile (Cressoniella) amparo

Megachile amparo (González, Revista Colombiana De Entomología 32(1):93-96, 2006) is the only high Andean leaf-cutter bee reported in Colombia and is possibly endemic to the Colombian Andes. Although it is frequently observed, even in urban areas, its biology and ecology remain unknown. The present study aimed to describe detailed aspects of its bionomy. Trap-nests were installed on the Campus of the Nueva Granada University (Cajicá, Colombia) from June/2018 to March/2020. The trap-nests were wooden blocks (25 × 15 × 14 cm) with 30 cavities of Ø = 1 cm and different lengths (50 mm, 75 mm, and 100 mm) lined with waxed paper straws. During the observations, an increasing number of trap-nests were installed, increasing from 250 to 720 cavities. The trap-nests were monitored three times a week, recording both the date the start and end building by female. Most of the nest were maintained in the field to estimate the sex ratio, cell survival, and total development time under natural conditions. Thirty-two nests were removed at different times of the observation period to establish number of cells per nest, and cells built per female per day. We incubated 20 cells from different nests at 18 °C, 22 °C, 26 °C, and 32 °C to estimate the base temperature, thermal constant k (developmental time in degree days), and cell survival. Young cells of different positions were dissected and weighed to characterize food provision and brood cells. Computerized tomography-CT scans were performed in 30 brood cells to determine if diapause occurred during prepupal stage. Females nested 7- and 10-cm-long cavities and the number of cells per nest varied with cavity length. The brood cells had a length of 1.23 ± 0.12 cm and a diameter of 0.92 ± 0.05 cm. The female spends 1.17 ± 0.29 days to build a brood cell. Food provision varied according to the position of the brood cell in the nest. The adults of M. amparo present a marked seasonality being more active during dry months. Base temperature and thermal constant k were different for males and females. The sex ratio is female biased (1.9:1), and cell survival in the field was 89% with no cleptoparasites or predators recorded.

Diapause and quiescence: dormancy mechanisms that contribute to the geographical expansion of mosquitoes and their evolutionary success

Mosquitoes are insects belonging to the order Diptera and family Culicidae. They are distributed worldwide and include approximately 3500 species, of which about 300 have medical and veterinary importance. The evolutionary success of mosquitoes, in both tropical and temperate regions, is due to the various survival strategies these insects have developed throughout their life histories. Of the many adaptive mechanisms, diapause and quiescence, two different types of dormancy, likely contribute to the establishment, maintenance and spread of natural mosquito populations. This review seeks to objectively and coherently describe the terms diapause and quiescence, which can be confused in the literature because the phenotypic effects of these mechanisms are often similar.

The evolutionary ecology of interactive synchronism: the illusion of the optimal phenotype

In this article, we discuss some ecological-evolutionary strategies that allow synchronization of organisms, resources, and conditions. Survival and reproduction require synchronization of life cycles of organisms with favourable environmental and ecological features and conditions. This interactive synchronization can occur directly, through pairwise or diffuse co-evolution, or indirectly, for example, as a result of actions of ecosystem engineers and facilitator species. Observations of specific interactions, especially those which have coevolved, may give the false impression that evolution results in optimal genotypes or phenotypes. However, some phenotypes may arise under evolutionary constraints, such as simultaneous evolution of multiple traits, lack of a chain of fit transitional forms leading to an optimal phenotype, or by limits inherent in the process of selection, set by the number of selective deaths and by interference between linked variants. Although there are no optimal phenotypes, optimization models applied to particular species may be useful for a better understanding of the nature of adaptations. The evolution of adaptive strategies results in variable life histories. These strategies can minimize adverse impacts on the fitness of extreme or severe environmental conditions on survival and reproduction, and may include reproductive strategies such as semelparity and iteroparity, or morphological, physiological, or behavioural traits such as diapause, seasonal polyphenism, migration, or bet-hedging. However, natural selection cannot indefinitely maintain intra-population variation, and lack of variation can ultimately extinguish populations.

Flower-Visiting Insects and Phenology of Lippia alba (Lamiales: Verbenaceae): Floral Color Changes and Environmental Conditions as Cues for Pollinators

Lippia alba (Mill.) N.E. Br. ex Britton & P. Wilson (Verbenaceae) is a herbal aromatic shrub with medicinal properties. Natural populations of this species are allogamous and self-incompatible. Therefore, this plant species relies on pollinators to outcross and maintain the genetic variability. Here, we investigated the floral phenology, pollen morphology, the floral visitor entomofauna, and the influence of climatic factors on the frequency of visits in L. alba flowers. The study was conducted at Federal University of Juiz de Fora Plant Experimental Area, southeast Brazil. The flowering of L. alba occurred throughout the whole year. The anthesis is diurnal and lasts 5 d. The nectar guide was visible from the onset of flowering until the third day. Pollen grains were classified as isopolar, oblate spheroidal, three-colporate (rare, four-colporate), surface tectate-perforate, and endoaperture lalongate, with median constriction. Insects from the order Hymenoptera were the most frequent visitors observed, followed by Lepidoptera, Thysanoptera, Diptera, and Hemiptera-Heteroptera. The preference of insects for flowers with nectar guides shows that the color is likely to be an important visual trait to increase the frequency of visits. Moreover, the climate variables temperature, relative humidity, wind speed, and light were important to define the composition of the most frequent floral visitors.

Immature mosquitoes (Diptera: Culicidae) in a eutrophic landfill tank from State of Rio de Janeiro, Brazil

INTRODUCTION

To determine the faunal composition of immature culicids inhabiting a percolation tank in the landfill of Sapucaia, State of Rio de Janeiro, Brazil, immature mosquitoes were collected over a two-day period during the third weeks of April, August and October 2011.

RESULTS

The species found were Culex usquatus, Lutzia bigoti, Anopheles argyritarsis and Limatus durhamii. This study is the first to report the colonization of eutrophic breeding sites by these species.

CONCLUSIONS

The oviposition behavior observed in this study suggests a secondary adaptation or change in habit to select eutrophic environments during the developmental stages of the observed species.