Fluctuating Environments, Sexual Selection and the Evolution of Flexible Mate Choice in Birds

Environmentally-induced fluctuation in the form and strength of natural selection can drive the evolution of morphology, physiology, and behavior. Here we test the idea that fluctuating climatic conditions may also influence the process of sexual selection by inducing unexpected reversals in the relative quality or sexual attractiveness of potential breeding partners. Although this phenomenon, known as ‘ecological cross-over’, has been documented in a variety of species, it remains unclear the extent to which it has driven the evolution of major interspecific differences in reproductive behavior. We show that after controlling for potentially influential life history and demographic variables, there are significant positive associations between the variability and predictability of annual climatic cycles and the prevalence of infidelity and divorce within populations of a taxonomically diverse array of socially monogamous birds. Our results are consistent with the hypothesis that environmental factors have shaped the evolution of reproductive flexibility and suggest that in the absence of severe time constraints, secondary mate choice behaviors can help prevent, correct, or minimize the negative consequences of ecological cross-overs. Our findings also illustrate how a basic evolutionary process like sexual selection is susceptible to the increasing variability and unpredictability of climatic conditions that is resulting from climate change

Pattern of asthma medication use among children from a large urban center in Brazil.

PURPOSE: Despite the advances in asthma therapeutics, there are few data on the use and determinants of anti-asthmatic drugs in the general population of children. This study describes the use of asthma medications among children in the general population and in children with current asthma, living in a large urban center in Brazil. METHODS: A population-based cross-sectional survey, aimed at analyzing asthma determinants, was conducted with 1,382 children aged 4-11 years, between February and May 2006, in Salvador, Brazil. At baseline, an extensive questionnaire was applied, including questions about the use of asthma medications in the last 12 months. RESULTS: In all studied children (n = 1,382) aged 4-11 years, oral beta2-agonists were the drugs most frequently used (9.8%), followed by short-acting inhaled beta2-agonists (4.3%) and systemic corticosteroids (1.6%). Anti-asthmatic drug use was higher among males than females, and it significantly decreased with age in both genders. A total of 312 children (22.6%) reported current asthma, and 62% of them were not being treated with any anti-asthmatic drugs. Of all those who reported following a certain type of treatment, 20% used oral beta2-agonists alone; 6.1%, short-acting inhaled beta2-agonists alone; and 4.8%, a combination of both drugs. Anti-asthmatic drug use did not differ according to socioeconomic status, except for the use of inhaled beta2-agonists and systemic corticosteroids. CONCLUSIONS: An overwhelming majority of asthmatic children were not using long-term medications for asthma, in particular inhaled corticosteroids, regardless of the severity of their disease. This result points to the deficiencies of the Brazilian public health system in recognizing this important pharmacological need for child care and thereby limiting the access of these children to a group of efficacious, available, and low risk therapeutic medications

High responsiveness in de novo shoot organogenesis induction of Passiflora cristalina (Passifloraceae), a wild Amazonian passion fruit species

The aim of the present study was to establish a regeneration system via de novo organogenesis from different types of non-meristematic explants of Passiflora cristalina. Leaf, hypocotyl, root segments, cotyledons, and endosperm of P. cristalina seeds were inoculated in Murashige and Skoog (MS)-basal medium, supplemented with different concentrations of 6-Benzyladenine (BA), Thidiazuron (TDZ), or Kinetin (KIN). BA was found to be the most efficient cytokinin in induction of de novo organogenesis from most the explants used in the study. The highest frequencies of adventitious bud formation in the hypocotyl and cotyledon explants were observed in medium supplemented with 1.0 mg L^−1 BA. For leaf and endosperm segments, the best concentration was 2.0 mg L^−1 BA; while for root segments, the highest mean values were observed with 1.0 mg L^−1 KIN. The different morphogenetic responses obtained from each explant source were characterized using light microscopy. P. cristalina revealed a remarkable organogenic potential, with superior production of adventitious shoots compared with the other Passiflora species evaluated elsewhere. These results will be helpful to establish a reproducible and reliable micropropagation protocol, as well as to implement conservationist and biotechnological-based genetic breeding strategies for this wild Passiflora species