The three oak species have formed a complex hybrid zone that is geographically structured as a mosaic, and comprising a wide range of genotypes, including hybrids between different species pairs, backcrosses and probable triple hybrids.

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Sexes and also within sex phenotypes, frequently differ in morphological traits associated with efficiency and performance in foraging and mating behaviours. In butterflies and other flying animals, phenotypic differences in wing size and traits associated with flight are involved in flight performance and individual fitness, but explorations of links among two or more traits and intrasexual differences are scarce. Foraging patterns were studied in a population of Heliconius charitonia butterflies having three phenotypes (females and two male phenotypes) which differ in their wing morphology and reproductive behaviour. As in previous studies, intersexual differences in foraging patterns were found; more interestingly, intrasexual differences were found between alternative male mating strategies. Using morphological and behavioural data, as well as data from previous flight analyses in Heliconius butterflies, we show that intrasexual differences may be explained by the energetic demands of each phenotype. Energetic expenditure is partially related to phenotypic variability in flight morphology and efficiency, and at least in both male phenotypes, differences may also be related to the energetic demands of alternative mating strategies.

Alternative male phenotypes may be a source of novel adaptive traits and may evolve under strong sexual selection. We studied interpopulation differences in male mating behavior related to receptive female synchrony in the monandrous pupal-mating butterfly Heliconius charitonia. In the population in which female-receptive pupae were more synchronous, larger males were unable to monopolize mates; variance in male mating success was lower; strength of sexual selection was weak; and all males competed for access to female pupae using the same strategy (pupal mating). In the population where no more than one female was receptive at a time (extreme asynchrony), only large males competed for pupae, and among these, only the largest individuals successfully mated. Thus, variance in mating success was higher, and sexual selection within pupal maters was stronger. In this population, smaller males patrolled large areas as an alternative mating behavior. When unmated females were experimentally released, small male size was associated with higher mating success. We suggest that alternative patrolling behavior may have evolved under strong sexual selection as a consequence of high asynchrony in receptive female availability in some populations.

Mexico is a center of diversification for the genus Quercus, with an important number of taxa occurring along the Trans-Mexican Volcanic Belt (TMVB). However, the impact of the interaction between historical and current climatic variation and geological heterogeneity in the TMVB on the genetic and phenotypic diversification within oak species has been scarcely investigated. We used chloroplast DNA microsatellites and a geometric morphometrics analysis of leaf shape to understand differentiation between populations of Quercus deserticola, which inhabits dry highlands along the TMVB.Ecological niche modeling (ENM) for present-day conditions and projections into past scenarios were performed to evaluate the influence of environmental variables on the evolutionary history of the species. Results showed high genetic diversity (h S =0.774) and high genetic structure (R ST =0.75) and the morphological subdivision of populations into two clusters, corresponding to the west/south and east/north sectors of the Q. deserticola geographic distribution. ENM indicated that the potential distribution of the species has remained similar from the late Pleistocene to the present. Seemingly, the phylogeographic structure of the species has been shaped by low seed-mediated gene flow and mostly local migration patterns. In turn, leaf shape is responding to climate differences either through phenotypic plasticity or local adaptation. is a volcanic mountain chain with nearly 8000 volcanic structures, extending about 1200 km west to east through central Mexico, from the Pacific coast to the Gulf of Mexico coast. Furthermore, the TMVB has a large environmental heterogeneity and has experienced important climatic changes from the Pliocene and Pleistocene to the present (Gómez-Tuena et al. 2007; Ferrari et al. 2012). Based on age, orogeny and tectonic features, the TMVB has been divided into four sectors (western, central, eastern and easternmost), each with its own characteristics (Gómez-Tuena et al. 2005; Ferrari et al. 2012). The TMVB has also been considered as a complex biogeographic unit (i. e. it shows a high degree of species endemism and diversity), with two sectors, west and east (Gámez et al. 2012;Torres-Miranda et al. 2013). Four main episodes of volcanic activity of the TMVB have occurred during different periods from the early Miocene to the present, affecting this region asynchronously, first the western and later the eastern sectors (Gómez-Tuena et al. 2005; Gámez et al. 2012; Ferrari et al. 2012).Several studies have found that the physiographic context of the TMVB has been important in the genetic structuring and phenotypic divergence of different species and how climatic and geologic events have modified their distributions in various time periods (Jaramillo-Correa et al. 2008; Gámez et al. 2012;Ruiz-Sánchez and Specht 2013;Torres-Miranda et al. 2013; Mastretta-Yanes et al. 2015; Rodríguez-Gómez and Ornelas . The TMVB has been shown to be a geographic barrier that limits the dispersion of plants and animals tha...

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Urbanization is one of the most significant land cover transformations, and while climate alteration is one of its most cited ecological consequences we have very limited knowledge on its effect on species’ thermal responses. We investigated whether changes in environmental thermal variability caused by urbanization influence thermal tolerance in honey bees (Apis mellifera) in a semi-arid city in central Mexico. Ambient environmental temperature and honey bee thermal tolerance were compared in urban and rural sites. Ambient temperature variability decreased with urbanization due to significantly higher nighttime temperatures in urban compared to rural sites and not from differences in maximum daily temperatures. Honey bee thermal tolerance breadth [critical thermal maxima (CTmax)—critical thermal minima (CTmin)] was narrower for urban bees as a result of differences in cold tolerance, with urban individuals having significantly higher CTmin than rural individuals, and CTmax not differing among urban and rural individuals. Honey bee body size was not correlated to thermal tolerance, and body size did not differ between urban and rural individuals. We found that honey bees’ cold tolerance is modified through acclimation. Our results show that differences in thermal variability along small spatial scales such as urban-rural gradients can influence species’ thermal tolerance breadths.

Abstract:Leaf fluctuating asymmetry (FA) is considered an important indicator of environmentally induced stress in plants, but the relationship between herbivory and FA levels is not clear. In this study we compared leaf size and shape, leaf area consumed by herbivorous insects, and FA levels between individuals of Heliocarpus pallidus (Tiliaceae) from two adjacent and contrasting habitat types (deciduous and riparian) in the Chamela–Cuixmala tropical dry-forest biosphere reserve. Ten individuals of H. pallidus were collected in each habitat type. Leaf shape was assessed using geometric morphometric techniques. Results indicated statistically significant differences in leaf shape between individuals from the two habitat types. In individuals from the riparian habitat leaf area (mean = 42.3 ± 1.2 cm2), herbivory levels (mean = 25.5% ± 1.8%) and FA levels (mean = 0.38 ± 0.04 cm) were significantly higher than in individuals from the deciduous habitat (17.2 ± 3.5 cm2; 9.6% ± 1.0% and 0.18 ± 0.04 cm, respectively). Within habitats, significant correlations were found between total leaf area and percentage leaf area removed by insects (R2 = 0.92 in riparian habitats, R2 = 0.9 in deciduous habitats), and between percentage leaf area removed and FA (R2 = 0.70 in riparian habitats, R2 = 0.79 in deciduous habitats). As has been suggested for other plant species, it is possible that the more favourable conditions in the riparian habitat enhance leaf growth, resulting in higher FA. Also, individuals in this habitat might be characterized by lower chemical defence and/or higher nutritional quality, which would explain the higher herbivory levels.