Attraction olfactive dans les systèmes de pollinisation Cyclocephalini-Araceae (Scarbaeidae, Dynastinae) et élevage en captivité de Cyclocephala

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

A new species of Beebeomyia Curran (Diptera: Richardiidae) from Brazil, with description of immature stages and notes on their association with Taccarum ulei (Araceae)

Wendt, Lisiane Dilli, Gonçalves, Eduardo Gomes, Maia, Artur Campos Dália (2018): A new species of Beebeomyia Curran (Diptera: Richardiidae) from Brazil, with description of immature stages and notes on their association with Taccarum ulei (Araceae). Zootaxa 4369 (4): 587-599, DOI: https://doi.org/10.11646/zootaxa.4369.4.

Pollination of Bactris guineensis (Arecaceae), a potential economically exploitable fruit palm from the Colombian Caribbean

Regardless of the ecological and economical importance of palms, their pollination strategies and the identities of their true pollinators are still contentious subjects. Bactris guineensis grows in open areas in lowland Caribbean Colombia. Its fruits have long been an important component of local economy and are now targeted for broader scale production for the Colombian market. We explored details of the reproductive biology of B. guineensis in its natural environment to understand the various elements of pollen flow dynamics that ensure optimal fruit yield. During two consecutive years, we investigated the phenology, floral biology and pollination ecology of a wild population of B. guineensis in the department of Sucre, northern Colombia. Monthly production of buds, inflorescences and ripe infructescences were quantified. Pollen carrying capacity, efficiency and fidelity of anthophilous insect species associated with B. guineensis were calculated and used to define their role as effective pollinators. Bactris guineensis is protogynous and exhibits ephemeral nocturnal anthesis. In spite of strict xenogamy the average reproductive success was over 75%, attributed to high pollen vector efficiency. Twenty-seven insect species representing three orders were recorded as floral visitors, but the only effective pollinators were minute flower weevils and sap beetles. At the beginning of the female phase of anthesis, when pistillate flowers are receptive, inflorescences of B. guineensis warm up to over 12 °C above ambient air and emit a balsamic scent, attracting swarms of several hundred to thousands of beetles loaded with pollen. A second, shorter-lasting floral heating event takes place by dusk in the following day (or the male phase), which culminates with pollen shedding of staminate flowers and departure of the pollinators. Anthesis events that are highly synchronized with activity patterns of specialized scent-oriented pollinators ensure the high reproductive success of B. guineensis at our study site. Plans for large scale production should prioritize insect-friendly practices and investigation on the role of volatile floral kairomones for pollinator attraction

Ancognatha vulgaris (Melolonthidae, Cyclocephalini): a specialized pollen-feeding scarab associated with wax palms (Ceroxylon spp., Arecaceae) in Andean cloud forests of Colombia

With 22 species, Ancognatha is the fourth most species-rich genus of Neotropical cyclocephaline scarabs (Melolonthidae, Cyclocephalini), an important group of anthophilous insects associated with palms (Arecaceae). Unlike other members of the tribe, which predominantly inhabit low-altitude ecosystems, Ancognatha spp. are most common in montane areas, at elevations of 1500 to over 4000 m a.s.l. In the cloud forests of the Andes of Colombia, we investigated the association between Ancognatha vulgaris and seven species of wax palms (Ceroxylon spp.) from 2009 to 2013. Male and female A. vulgaris can be characterized as specialized florivores recovered in abundances of up to 40 individuals at both male and female inflorescences of all studied species of wax palms, which they also used for shelter and as aggregation sites for mating. The night-active beetles preferably fed on the pollen released in high quantities by staminate flowers of male inflorescences, but were also observed gnawing on the pistillate flowers of female inflorescences. We hypothesize that wax palm inflorescences are a key resource for the maintenance of populations of A. vulgaris under the extreme environmental conditions of Andean montane ecosystems, an assumption supported by their overlapping biogeographical distributions

Pollination of Philodendron acutatum (Araceae) in the atlantic forest of northeastern Brazil: a single scarab beetle species guarantees high fruit set

International audiencePhilodendron 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 fragrancesgiven off during the female phase of anthesis, along with endogenous heating of the spadix, whose temperatures were recorded at more than 11C 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 reproductivedependence of the plant to this scarab beetle species. Dihydro-b-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

Orchestrated flowering and interspecific facilitation: Key factors in the maintenance of the main pollinator of coexisting threatened species of andean wax palms (ceroxylon spp.)

Solitary, dioecious, and mostly endemic to Andean cloud forests, wax palms (Ceroxylon Bonpl. ex DC. spp.) are currently under worrisome conservation status. The establishment of management plans for their dwindling populations rely on detailed biological data, including their reproductive ecology. As in the case of numerous other Neotropical palm taxa, small beetles are assumed to be selective pollinators of wax palms, but their identity and relevance in successful fruit yield were unknown. During three consecutive reproductive seasons we collected data on population phenology and reproductive and floral biology of three syntopic species of wax palms native to the Colombian Andes. We also determined the composition of the associated flower-visiting entomofauna, quantifying the extent of the role of individual species as effective pollinators through standardized value indexes that take into consideration abundance, constancy, and pollen transport efficiency. The studied populations of C. parvifrons (Engel) H. Wendl., C. ventricosum Burret, and C. vogelianum (Engel) H. Wendl. exhibit seasonal reproductive cycles with marked temporal patterns of flower and fruit production. The composition of the associated flower-visiting entomofauna, comprised by ca. 50 morphotypes, was constant across flowering seasons and differed only marginally among species. Nonetheless, a fraction of the insect species associated with pistillate inflorescences actually carried pollen, and calculated pollinator importance indexes demonstrated that one insect species alone, Mystrops rotundula Sharp, accounted for 94%-99% of the effective pollination services for all three species of wax palms. The sequential asynchronous flowering of C. parvifrons, C. ventricosum, and C. vogelianum provides an abundant and constant supply of pollen, pivotal for the maintenance of large populations of their shared pollinators, a cooperative strategy proven effective by high fruit yield rates (up to 79%). Reproductive success might be compromised for all species by the population decline of one of them, as it would tamper with the temporal orchestration of pollen offer

Co-pollination, constancy, and efficiency over time: small beetles and the reproductive success of Acrocomia aculeata (Arecaceae) in the Colombian Orinoquia

Acrocomia aculeata is under accelerated domestication due to the high yield and quality of the oils obtained from the fruits. Key details about its reproduction and fruit production, notably its dependence on cross-pollination, have not been thoroughly assessed. In the course of three successive reproductive seasons, we investigated the phenology, floral biology, pollination ecology, and reproductive efficiency of a natural population of A. aculeata in the department of Casanare, Colombian Orinoquia. We determined the effective pollinators among floral visitors based on their abundance, pollen carrying capacity, and constancy in association with receptive female-phase inflorescences. The studied population of A. aculeata exhibited a seasonal reproductive cycle, producing inflorescences during the drier months of December to April (peaking in March) and mature fruits from October to March. Each individual produces six to ten protogynous inflorescences, with a female phase that lasts ca. 12 h and a male phase extending for four to five days. A total of 48 insect species were observed in association with A. aculeata, averaging over 3500 visitors per anthetic female-phase inflorescence. Flower weevils (Andranthobius spp.; Derelomini) and small sap beetles (Mystrops sp.; Mystropini) were the most abundant visiting species and main pollinators, accounting for 90–95% of effective pollination services. Their high efficiency as pollen vectors was evident, as fructification rates reached on average 65.5% during the three years of study. Our findings support the assumption that co-pollination in A. aculeata evolved as a specialized strategy to maintain a high and temporally stable reproductive efficiency over time

Flowering mechanisms, pollination strategies and floral scent analyses of syntopically co-flowering Homalomena spp. (Araceae) on Borneo

In this study, the flowering mechanisms and pollination strategies of seven species of the highly diverse genus Homalomena (Araceae) were investigated in native populations of West Sarawak, Borneo. The floral scent compositions were also recorded for six of these species. The selected taxa belong to three out of four complexes of the section Cyrtocladon (Hanneae, Giamensis and Borneensis). The species belonging to the Hanneae complex exhibited longer anthesis (53–62 h) than those of the Giamensis and Borneensis complexes (ca. 30 h). Species belonging to the Hanneae complex underwent two floral scent emission events in consecutive days, during the pistillate and staminate phases of anthesis. In species belonging to the Giamensis and Borneensis complexes, floral scent emission was only evident to the human nose during the pistillate phase. A total of 33 volatile organic compounds (VOCs) were detected in floral scent analyses of species belonging to the Hanneae complex, whereas 26 VOCs were found in samples of those belonging to the Giamensis complex. The floral scent blends contained uncommon compounds in high concentration, which could ensure pollinator discrimination. Our observations indicate that scarab beetles (Parastasia gestroi and P. nigripennis; Scarabaeidae, Rutelinae) are the pollinators of the investigated species of Homalomena, with Chaloenus schawalleri (Chrysomelidae, Galeuricinae) acting as a secondary pollinator. The pollinators utilise the inflorescence for food, mating opportunities and safe mating arena as rewards. Flower-breeding flies (Colocasiomyia nigricauda and C. aff. heterodonta; Diptera, Drosophilidae) and terrestrial hydrophilid beetles (Cycreon sp.; Coleoptera, Hydrophilidae) were also frequently recovered from inflorescences belonging to all studied species (except H. velutipedunculata), but they probably do not act as efficient pollinators. Future studies should investigate the post-mating isolating barriers among syntopically co-flowering Homalomena sharing the same visiting insects