Pollinators show flower colour preferences but flowers with similar colours do not attract similar pollinators

Reverté S., Retana J., Gómez J.M., Bosch J. (2016) Pollinators show flower colour preferences but flowers with similar colours do not attract similar pollinators. Annals of Botany. 118: 249-257.
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Doi: 10.1093/aob/mcw103

Resum:

Background and aims Colour is one of the main floral traits used by pollinators to locate flowers. Although pollinators show innate colour preferences, the view that the colour of a flower may be considered an important predictor of its main pollinators is highly controversial because flower choice is highly context-dependent, and initial innate preferences may be overridden by subsequent associative learning. Our objective is to establish whether there is a relationship between flower colour and pollinator composition in natural communities. Methods We measured the flower reflectance spectrum and pollinator composition in four plant communities (85 plant species represented by 109 populations, and 32 305 plant-pollinator interactions in total). Pollinators were divided into six taxonomic groups: bees, ants, wasps, coleopterans, dipterans and lepidopterans. Key Results We found consistent associations between pollinator groups and certain colours. These associations matched innate preferences experimentally established for several pollinators and predictions of the pollination syndrome theory. However, flowers with similar colours did not attract similar pollinator assemblages. Conclusions The explanation for this paradoxical result is that most flower species are pollination generalists. We conclude that although pollinator colour preferences seem to condition plant-pollinator interactions, the selective force behind these preferences has not been strong enough to mediate the appearance and maintenance of tight colour-based plant-pollinator associations. © 2016 The Author 2016.

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Habitat determinants of abundance, structure and composition of flying Hymenoptera communities in mountain old-growth forests

Arnan X., Bosch J., Comas L., Gracia M., Retana J. (2011) Habitat determinants of abundance, structure and composition of flying Hymenoptera communities in mountain old-growth forests. Insect Conservation and Diversity. 4: 200-211.
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Doi: 10.1111/j.1752-4598.2010.00123.x

Resum:

1.Old-growth forests have features that endow them with an extraordinary ecological value. These forests are sources of habitat diversity and, consequently, biodiversity, which makes them a basic objective of conservation programs. Insects have been traditionally used as indicators of forest condition. 2.The aim of this study is to uncover patterns of Hymenoptera abundance and diversity, and their relationship with structural features in old-growth forests. We use pan traps to sample the community of flying Hymenoptera in two old-growth forest types (silver fir and mountain pine) with important structural differences. 3.Compared to other surveys of local Hymenoptera communities, our sampling yielded an extremely high number of species (630). 4.At the plot level, the two forest types showed important differences in family richness and diversity, but not in abundance or in species richness and diversity. However, variability in species richness was higher among pine than silver fir plots, leading to overall higher species richness in the former. 5.Species composition also differed between pine than silver fir forests, and these differences were related to important structural differences between the two forest types. 6.Canonical correspondence and multiple regression analysis yielded contrasting habitat requirements among Hymenoptera families and functional groups (bees, sawflies, parasitic wasps and predatory wasps). 7.We conclude that flying Hymenoptera communities can be used as good indicators of forest structure, habitat complexity and conservation status. © 2010 The Authors. Insect Conservation and Diversity © 2010 The Royal Entomological Society.

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Relación entre el grado de madurez del bosque y las comunidades de himenópteros voladores y micromamíferos en el Parque Nacional de Aiguestortes i Estany de Sant Maurici. En: Proyectos de investigación en parques nacionales: 2006-2009. L. Ramírez y B. A

Comas L, Arnan X, Gracia M, Retana J, Bosch J (2010) Relación entre el grado de madurez del bosque y las comunidades de himenópteros voladores y micromamíferos en el Parque Nacional de Aiguestortes i Estany de Sant Maurici. En: Proyectos de investigación en parques nacionales: 2006-2009. L. Ramírez y B. A sensio (Eds.). Organismo Autónomo de Parques Nacionales pp. 327-341.

Changes of dominant ground beetles in black pine forests with fire severity and successional age

Rodrigo A., Sardà-Palomera F., Bosch J., Retana J. (2008) Changes of dominant ground beetles in black pine forests with fire severity and successional age. Ecoscience. 15: 442-452.
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Doi: 10.2980/15-4-3117

Resum:

This study analyzes the effect of fire on the composition and abundance of ground beetles in Pinus nigra forests. We used pitfall traps to sample beetles in burned P. nigra forests in Catalonia (Spain). Since fire dramatically alters forest structure and composition and beetles follow vegetation changes, we expected drastic changes in beetle composition and abundance immediately after fire. Because P. nigra forests do not recover after fire, we also expected beetles in burned and unburned areas to differ along a chronosequence. Beetle abundance per plot increased in canopy-fire-burned areas, but per plot species richness, diversity, and dominance were not affected by fire. Species composition varied depending on fire intensity. Some species were associated with canopy fire and low vegetation cover. Other species were associated with shrub cover and time since fire. Finally, some species were not dependent on fire or vegetation cover. Beetle abundance in burned areas was independent of time since fire. This lack of medium-term convergence between burned and unburned P. nigra forests agrees with our second hypothesis. Given the increase in fire frequency and size in submediterranean areas and the observed slow recovery of beetle species, a decline in beetle diversity at a regional scale is expected.

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Foraging behaviour and pollinating effectiveness of Osmia cornuta (Hymenoptera: Megachilidae) and Apis mellifera (Hymenoptera: Apidae) on "Comice" pear.

Monzón VH, Bosch J, Retana J (2004) Foraging behaviour and pollinating effectiveness of Osmia cornuta (Hymenoptera: Megachilidae) and Apis mellifera (Hymenoptera: Apidae) on "Comice" pear. Apidologie 35:575-585.

Flowering phenology, floral traits and pollinator composition in a herbaceous Mediterranean plant community

Bosch J., Retana J., Cerdá X. (1997) Flowering phenology, floral traits and pollinator composition in a herbaceous Mediterranean plant community. Oecologia. 109: 583-591.
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Doi: 10.1007/s004420050120

Resum:

The relationships between flowering plants and their insect visitors were studied in a Mediterranean grassland in north-east Spain. Floral traits (size, shape, symmetry, and colour), floral rewards (pollen and nectar), flowering period, and floral visitors were recorded for the 17 most abundant plants in the community. Flowering was year-round, but most species flowered in spring. The three species that flowered after spring had small flowers, but the distribution of floral features (including rewards offered) did not show a strong seasonality. Ants contributed 58.5% to the flower visits recorded. Other frequent visitors were beetles (12%), flies (9.5%), honey bees (6.4%), wild bees (6.4%), and wasps (5.2%). Honey bees were most abundant in April, wild bees from April to July, beetles from May to July, and ants from May to September. The lack of tight plant-insect associations was the rule, with most plant species visited by a rather diverse array of insects representing two or more orders. The plant species having narrower spectra of visitors either had flower rewards exposed or attracted mostly illegitimate visitors. By means of correspondence analysis four categories of plants were defined according to their main groups of visitors: (1) honey bees and large wild bees: (2) large wild bees; (3) ants and beetles; and (4) beetles and small-sized bees. The Mantel test was used to calculate correlations among four matrices representing similarities in visitors attracted, floral morphological traits, pollen-nectar rewards, and blooming time, respectively. In spite of seasonality shown by the different insect groups, results indicate that the observed patterns of visitor distribution among plants were most affected by pollen-nectar rewards.

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Fruiting phenology of carob (Ceratonia siliqua, Cesalpinaceae).

Bosch J, Retana J, Ramoneda J, García Del Pino F (1997) Fruiting phenology of carob (Ceratonia siliqua, Cesalpinaceae). Israel Journal of Plant Sciences 44:359-368.

Flowering phenology of carob, Ceratonia siliqua (Cesalpinaceae).

Retana J, Bosch J, Ramoneda J, García del Pino F (1994) Flowering phenology of carob, Ceratonia siliqua (Cesalpinaceae). Journal of Horticultural Science 69:97-103.

Estrategias alternativas en el ciclo de vida de tres hormigas mediterráneas.

Cerdà X, Retana J, Bosch J, Cros S (1992) Estrategias alternativas en el ciclo de vida de tres hormigas mediterráneas. Orsis 7:87-96.

Comparación de varios métodos de estudio de ritmos de actividad en hormigas (Hymenoptera, Formicidae).

Retana J, Cerdà X, Bosch J, Alsina A (1990) Comparación de varios métodos de estudio de ritmos de actividad en hormigas (Hymenoptera, Formicidae). Butlletí de la Institució Catalana d'Història Natural 58:65-72.

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