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The subtribe Espeletiinae (Asteraceae), endemic to the high-elevations in the Northern Andes, exhibits an exceptional diversity of species, growth-forms, and reproductive strategies. This complex of 140 species includes large trees, dichotomous trees, shrubs and the extraordinary giant caulescent rosettes, considered as a classic example of adaptation in tropical high-elevation ecosystems. The subtribe has also long been recognized as a prominent case of adaptive radiation, but the understanding of its evolution has been hampered by a lack of phylogenetic resolution. Herein, we produce the first fully resolved phylogeny of all morphological groups of Espeletiinae, using whole plastomes and about a million nuclear nucleotides obtained with an original de novo assembly procedure without reference genome, and analyzed with traditional and coalescent-based approaches that consider the possible impact of incomplete lineage sorting and hybridization on phylogenetic inference. We show that the diversification of Espeletiinae started from a rosette ancestor about 2.3 Ma, after the final uplift of the Northern Andes. This was followed by two independent radiations in the Colombian and Venezuelan Andes, with a few trans-cordilleran dispersal events among low-elevation tree lineages but none among high-elevation rosettes. We demonstrate complex scenarios of morphological change in Espeletiinae, usually implying the convergent evolution of growth-forms with frequent loss/gains of various traits. For instance, caulescent rosettes evolved independently in both countries, likely as convergent adaptations to life in tropical high-elevation habitats. Tree growth-forms evolved independently three times from the repeated colonization of lower elevations by high-elevation rosette ancestors. The rate of morphological diversification increased during the early phase of the radiation, after which it decreased steadily towards the present. On the other hand, the rate of species diversification in the best-sampled Venezuelan radiation was on average very high (3.1 spp/My), with significant rate variation among growth-forms (much higher in polycarpic caulescent rosettes). Our results point out a scenario where both adaptive morphological evolution and geographical isolation due to Pleistocene climatic oscillations triggered an exceptionally rapid radiation for a continental plant group. [ABSTRACT FROM AUTHOR]

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Information on animal reproduction is critical for the application of wildlife conservation plans. The lesser long-nosed bat (Leptonycteris yerbabuenae) is classified as threatened in Mexico; however, many aspects of its reproductive biology are still unstudied. The formation of a dorsal patch in males of Leptonycteris spp. during the mating period has been described and evidence suggests this patch is involved in reproductive behavior. We determined the male reproductive cycle of L. yerbabuenae over time based on the seminiferous cycle. We then related these internal indicators with 3 external indicators--testis size, dorsal patch size, and female/male ratio in the population. Finally, we evaluated whether the epididymis functions in long-term sperm storage. Bats were captured monthly and external indicators were registered. Three adult males were euthanized each month for the evaluation of internal indicators. We determined only 1 period of spermatogenesis per year beginning in September and completing in January. The seminiferous epithelium cycle showed 11 stages and 14 steps. Internal reproductive indicators were correlated with external indicators. External testis size and female/male ratio were positively correlated with dorsal patch size. A testis size of approximately 48.2 mm² corresponded with the beginning of sperm production. The epididymis was not involved in long-term sperm storage. This study provides the 1st description in L. yerbabuenae of the annual timing of the male reproductive cycle based on histological characteristics, and also reports a relationship between the size of the dorsal patch and male reproductive function. [ABSTRACT FROM AUTHOR]

The Agave genus embraces many species with outstanding ecological and economic importance in the arid regions of the Americas. Even though this genus covers a broad geographic distribution, our knowledge on the population genetics of species is concentrated in taxa located in North America. Recently, it has been demonstrated that plant domestication decreases levels of genetic diversity in managed populations and increases population structure with respect to wild populations. We examined levels of allozyme diversity (N = 17 loci) and population structure of Agave cocui, the species at the southern limit of distribution of the genus. We sampled 7 wild populations (N = 30–35 individuals per population) representative of the geographic distribution of the species in Venezuela. Among the agaves studied, A. cocui has some of the lowest estimates of genetic diversity (He[species] = 0.059, He[population] = 0.054) reported until present. We propose that this condition is probably linked to the recent origin of this species in arid and semiarid regions of Colombia and Venezuela, probably through one or a few founder events. The lowest estimates of genetic diversity were associated with small populations in very restricted arid patches; but also with overexploitation of rosettes for production of fermented drinks and fibers. Santa Cruz de Pecaya, one of the 2 centers of economic use of agaves in northwestern Venezuela presented one of the lowest values of genetic variability, a sign suggesting that human impact represents a significant threat to the available genetic pool that this species possesses in the region. [ABSTRACT FROM PUBLISHER]

Deals with a study which examined the dependence of the nectar feeding bats Leptonycteris curasoe and Glossophaga longirostris on agaves and cacti as food sources. Materials and methods; Results; Discussion.