Abstract: Philodendron acutatum (Araceae) is a hemiepiphyte common to the Atlantic Forest of northeastern Brazil. In two localities, we studied the species' breeding system and associations with flower-visiting insects, along with an analysis of its floral scent composition. The fruit set of self-incompatible P. acutatum was high, more than 90%, and inflorescences were exclusively pollinated by one species of scarab beetle, Cyclocephala celata (Scarabaeidae, Dynastinae). Pollinators are drawn toward the inflorescences at dusk by strong floral fragrances given off during the female phase of anthesis, along with endogenous heating of the spadix, whose temperatures were recorded at more than 11 degrees C above ambient air. Two other species of flower-visiting Cyclocephala were also consistently recovered in blacklight trappings during the flowering period of P. acutatum. The fact that only C. celata was found in association with P. acutatum suggests a local reproductive dependence of the plant to this scarab beetle species. Dihydro-beta-ionone and 2-hydroxy-5-methyl-3-hexanone, a rare volatile molecule so far unreported as a floral compound, together accounted for more than 97% of the unique scent composition of P. acutatum and might be involved in specific attraction of C. celata.

Abstract: In this paper we give a priori error estimates for finite element approximations of linear parabolicproblems with pointwise control and incomplete data. We discretise the optimal control problemby using piecewise linear and continuous finite elements for the space discretisation of the state,and we use the backward Euler scheme for time discretisation. We prove a priori error estimates forthe state, the adjoint-state as well as for the low-regret pointwise optimal control.

Abstract: Pollination in the genus Arum appears to be in general a complex deceptive pollination process. The genus Arum is composed of 28 species, all belonging to the subgenus Arum, except A. pictum, the only species of the subgenus Gymnomesium, which is basal and sister to all other Arum species. The aim of this paper is to document the pollination ecology of the insular Arum pictum, the only Arum species to flower in autumn, on the island of Corsica (France). The anthesis cycle of A. pictum occurs during the day, attracting sphaerocerid flies and staphylinid beetles early in the morning and late in the afternoon of the first day. The pollen is released from the anthers early in the morning of the second day before the departure of the insects. Its thermogenic cycle matches the anthesis cycle with an original and unique, bimodal temperature pattern of the appendix (morning and afternoon), contrary to the unimodal pattern found in all other studied Arum species. Data from reproductive success and seed sets suggest that sexual reproduction in this species is limited by pollen (e.g. attracting lured insects) rather than by resources. The biology of this Western Mediterranean species appears to be different from other Western European Arum and close to some Eastern Mediterranean species. Further studies are needed to establish whether Arum pictum represents some ancestral stage or whether its peculiar biological traits are adapted to its insular distribution.

Abstract: We tested if nesting habits influence ant feeding preferences and predatory behavior in the monophyletic genus Pseudomyrmex (Pseudomyrmecinae) which comprises terrestrial and arboreal species, and, among the latter, plant-ants which are obligate inhabitants of myrmecophytes (i.e., plants sheltering so-called plant-ants in hollow structures). A cafeteria experiment revealed that the diet of ground-nesting Pseudomyrmex consists mostly of prey and that of arboreal species consists mostly of sugary substances, whereas the plant-ants discarded all the food we provided. Workers forage solitarily, detecting prey from a distance thanks to their hypertrophied eyes. Approach is followed by antennal contact, seizure, and the manipulation of the prey to sting it under its thorax (next to the ventral nerve cord). Arboreal species were not more efficient at capturing prey than were ground-nesting species. A large worker size favors prey capture. Workers from ground- and arboreal-nesting species show several uncommon behavioral traits, each known in different ant genera from different subfamilies: leaping abilities, the use of surface tension strengths to transport liquids, short-range recruitment followed by conflicts between nestmates, the consumption of the prey's hemolymph, and the retrieval of entire prey or pieces of prey after having cut it up. Yet, we never noted group ambushing. We also confirmed that Pseudomyrmex plant-ants live in a kind of food autarky as they feed only on rewards produced by their host myrmecophyte, or on honeydew produced by the hemipterans they attend and possibly on the fungi they cultivate. © 2014 Springer-Verlag Berlin Heidelberg.