Species diversity and community structure in neotropical fruit-feeding butterflies

Chemical secretions that are explicitly tied to species recognition may potentially be informative for phylogenetic reconstruction, especially when traditional morphological or molecular characters lack resolution. Anal sac secretions from 16 species within the family Felidae (order Carnivora) were chemically analysed and their utility as phylogenetic characters was assessed. Results were generally consistent across the different chemical data types (e.g. glycolipids, neutral lipids, or phospholipids). Two major clades were indicated, falling out according to body size: one for species greater than 30 kg (Panthera, Uncia, and Puma) and another for those less than 12 kg (remaining species). The primary solutions agreed with respect to the species pairs Prionailurus + Leptailurus, Caracal + Lynx, Oncifelis+Leopardus, Otocolobus+Felis, Panthera leo + P pardus, and P. tigris + Uncia. The only area of disagreement between chemical types was the positioning of the mountain lion (Puma concolor); however, this species appears to cluster with the cheetah (Acinonyx jubatus) in the Tjig cat clade. Although our solutions differ from six previously proposed hypotheses of felid phylogeny (morphological and molecular), the previous estimates all differ strongly amongst themselves reflecting the historical uncertainty regarding felid systematics. Phytogenies derived from the lipid data were very robust and decisive. Few equally most parsimonious trees were obtained, consistency indices were much higher than their expected values, and bootstrap and Bremer support values were also high. Thus, our findings illustrate the species-specific nature of chemical signals and their usefulness as phylogenetic characters.     

Impacts of floral gender and whole-plant gender on floral evolution in Ecballium elaterium (Cucurbitaceae)

Investigation of gender specialization in plants has led to several theories on the evolution of sexual dimorphism: reproductive compensation, based on enhanced reproductive efficiency with gender specialization (flowers should be larger on dioecious plants); Bateman's Principle, based on sex-specific selection (display for pollinator attraction in males and seed set in females); and intersexual floral mimicry, based on mimicry of a reward-providing gender by a non-reward providing gender (reduced dimorphism in dioecious plants due to increased spatial separation of male and female flowers). These theories were evaluated in Ecballium elaterium, which contains two subspecies, elaterium (monoecious) and dioicum (dioecious). Our results show that flowers of the dioecious subspecies are larger and allocate more to reproductive organs than do flowers of the monoecious subspecies. Both subspecies are sexually dimorphic (male flowers larger than female flowers). Variance in flower size among populations is greater in the dioecious subspecies. Finally, there is sufficient genetic variation to enable ongoing response to selection; genetic correlation constraints on independent response of female and male flowers may be stronger in the monoecious subspecies. Our findings provide support for aspects of all three theories, suggesting that the evolution of floral dimorphism is based on a complex interplay of factors.