Evaluation of DNA barcoding and identification of new haplomorphs in Canadian deerflies and horseflies.

This paper reports the first tests of the suitability of the standardized mitochondrial cytochrome c oxidase subunit I (COI) barcoding system for the identification of Canadian deerflies and horseflies. Two additional mitochondrial molecular markers were used to determine whether unambiguous species recognition in tabanids can be achieved. Our 332 Canadian tabanid samples yielded 650 sequences from five genera and 42 species. Standard COI barcodes demonstrated a strong A + T bias (mean 68.1%), especially at third codon positions (mean 93.0%). Our preliminary test of this system showed that the standard COI barcode worked well for Canadian Tabanidae: the target DNA can be easily recovered from small amounts of insect tissue and aligned for all tabanid taxa. Each tabanid species possessed distinctive sets of COI haplotypes which discriminated well among species. Average conspecific Kimura two-parameter (K2P) divergence (0.49%) was 12 times lower than the average divergence within species. Both the neighbour-joining and the Bayesian methods produced trees with identical monophyletic species groups. Two species, Chrysops dawsoni Philip and Chrysops montanus Osten Sacken (Diptera: Tabanidae), showed relatively deep intraspecific sequence divergences (∼ 10 times the average) for all three mitochondrial gene regions analysed. We suggest provisional differentiation of Ch. montanus into two haplotypes, namely, Ch. montanus haplomorph 1 and Ch. montanus haplomorph 2, both defined by their molecular sequences and by newly discovered differences in structural features near their ocelli.

Sun-tracking solar furnaces in high arctic flowers: significance for pollination and insects.

Heliotropic flowers (Dryas integrifolia, Papaver radicatum) act, in sunshine, as solar reflectors, their corollas focusing heat on the sporophylls. Considerable intrafloral temperatures are generated. Winds above 3.8 meters per second and cloud abolish the effect. Insects that bask in the flowers also gain heat. The phenomena areimportant in maximizing the small heat budget.

Effect of bumble bee (Hymenoptera: Apidae) pollination intensity on the quality of greenhouse tomatoes.

Laboratory studies were conducted to assess tomato, Lycopersicon esculentum Mill. (Solanaceae), quality in relation to the level of buzz-pollination by bumble bees. Studies were conducted in commercial tomato greenhouses in the Leamington, Ontario, area to categorize bruising of tomato anther cones by bumble bees into five levels of bruising. The number of pollen grains per stigma was determined for each bruising level, and the bruising level was found to be a good predictor of stigmatic pollen load. Experimental flowers were pollinated by bumble bees and assigned to bruising levels based on the degree of anther cone discoloration. Fruit set, tomato weight, minimum diameter, the number of days until ripe, roundness, weight, percentage sugars, and number of seeds were assessed and compared among bruising level. Fruit set in flowers receiving no pollination visits was 30.2%, whereas, 83.3, 84.4, 81.2, and 100% of the flowers set fruit in bruising levels 1, 2, 3, and 4, respectively. Minimum diameter, number of seeds, and tomato weight all increased from no bruising to different levels of bruising. There was no increase in weight or diameter above a bruising level of 1, and no increase in the number of seeds per fruit after a bruising level of 2. We found that pollination of tomato flowers greater than a bruising level of 2 (corresponding to approximately one to two bee visits) did not result in a significant increase in quality.

Bumble bee (Hymenoptera: Apidae) activity and pollination levels in commercial tomato greenhouses.

Commercial greenhouse studies were conducted to assess levels of pollination of tomato (Lycopersicon esculentum Mill.) flowers in relation to bumble bee (Bombus impatiens Cresson) colony activity and colony densities. For the assessment of pollination levels of tomato flowers, five categories were defined based on bruising levels caused by bumble bee pollination. Colony activity was measured as bee trips per ha/d using electric powered photodiode monitors inserted into the hive entrance. Levels of pollination were positively correlated with bee activity levels, up to a mean of approximately 400 pollen grains per stigma per day, after which greater activity did not result in further increases in daily pollination levels. Densities of colonies in the commercial greenhouses studied ranged from 7.6 to 19.8 colonies per hectare with a mean of 11.6 +/- 0.9. We found that an average activity of 2,000 bee trips per hectare per day was more than adequate to ensure sufficient pollination, and that this level of activity could be achieved with 7-15 colonies per hectare, depending on greenhouse conditions. Greenhouses requiring >15 colonies per hectare to achieve this level of pollination may be able to increase bee activity through alteration of greenhouse conditions. Across 50-m rows of tomato plants, levels of pollination decreased with increasing distance from bee colonies, suggesting that colonies should be evenly distributed throughout the greenhouses.

Records on floral biology and visitors of Jacquemontia montana (Moric.) Meisn. (Convolvulaceae) in Mucugê, Bahia.

We present the first records on pollination biology of Jacquemontia montana (Moric.) Meisn. (Convolvulaceae), a widespread climber in the Chapada Diamantina. Our objectives were to (1) characterise flower morphology and biology of J. montana; (2) sample flower visitors and (3) make inferences about potential pollinators, based on foraging behaviour. Observations and sampling were performed on two patches from 8:00 AM to 3:30 PM, May 15th to 16th, 2007. The corolla is bowl shaped, pentamerous, gamopetalous, actinomorphic, and yellow, with a mean diameter of 22.43 +/- 1.81 mm, the depth being variable during flower phases. Stigma receptivity lasted from 8:00 AM-3:30 PM and pollen viability from 9:00 AM-3:30 PM Pollen. showed great decline in number but not in viability during anthesis. Nectarivorous (Coleoptera, Diptera, Hymenoptera) and herbivorous (Orthoptera) insects were found on the flowers. Both male and female bees (Dialictus spp., Robertson 1902) were the most frequent flower visitor. The bees' behaviour, and time spent on flowers, varied according to the resource gathered (i.e., pollen or nectar). The Dialictus species are likely to be the main pollinator of J. montana, considering the frequency, contact with reproductive parts, and carrying only J. montana pollen spread over the ventral part of the thorax, abdomen and legs. Although not quantified, nectar may still be available in the afternoon, considering the behaviour of bees on flowers during this time. Pollen:ovule ration that was1.200:4, suggests facultative xenogamy.

Records on floral biology and visitors of Jacquemontia montana (Moric.) Meisn. (Convolvulaceae) in Mucugê, Bahia / Registros sobre a biologia floral e visitantes de Jacquemontia montana (Moric.) Meisn. (Convolvulaceae) em Mucugê, Bahia

We present the first records on pollination biology of Jacquemontia montana (Moric.) Meisn. (Convolvulaceae), a widespread climber in the Chapada Diamantina. Our objectives were to (1) characterise flower morphology and biology of J. montana; (2) sample flower visitors and (3) make inferences about potential pollinators, based on foraging behaviour. Observations and sampling were performed on two patches from 8:00 AM to 3:30 PM, May 15th to 16th, 2007. The corolla is bowl shaped, pentamerous, gamopetalous, actinomorphic, and yellow, with a mean diameter of 22.43 ± 1.81 mm, the depth being variable during flower phases. Stigma receptivity lasted from 8:00 AM-3:30 PM and pollen viability from 9:00 AM-3:30 PM Pollen. showed great decline in number but not in viability during anthesis. Nectarivorous (Coleoptera, Diptera, Hymenoptera) and herbivorous (Orthoptera) insects were found on the flowers. Both male and female bees (Dialictus spp., Robertson 1902) were the most frequent flower visitor. The bees' behaviour, and time spent on flowers, varied according to the resource gathered (i.e., pollen or nectar). The Dialictus species are likely to be the main pollinator of J. montana, considering the frequency, contact with reproductive parts, and carrying only J. montana pollen spread over the ventral part of the thorax, abdomen and legs. Although not quantified, nectar may still be available in the afternoon, considering the behaviour of bees on flowers during this time. Pollen:ovule ration that was1.200:4, suggests facultative xenogamy.

Apresentamos os primeiros registros sobre a biologia da polinização de Jacquemontia montana (Moric.) Meisn. (Convolvulaceae), uma trepadeira com ampla distribuição na Chapada Diamantina, Bahia. Os objetivos deste estudo foram: (1) caracterizar a morfologia e biologia floral; (2) amostrar os visitantes; e (3) inferir os possíveis polinizadores, baseando-se no comportamento de forrageio. Observações e amostragens foram conduzidas em duas manchas das 8:00 às 15:30 horas, nos dias 15 e 16 de maio de 2007. A corola é amarela, tem forma de disco, pentâmera, gamopétala, actinomorfa. A corola exposta tem largura média de 22,43 ± 1,81 mm. A receptividade estigmática ocorre das 8:00 às 15:30 horas e a viabilidade polínica das 9:00 às 15:30 horas, se sobrepondo fortemente. O pólen, porém, apresentou forte declínio em número, devido à retirada pelos visitantes, mas não em viabilidade durante a antese. Insetos nectarívoros (Coleoptera, Diptera, Hymenoptera) e herbívoros (Orthoptera) visitaram as flores. Hymenoptera incluiu representantes das famílias Formicidae (formigas) e Halictidae (Dialictus spp.). Machos e fêmeas de Dialictus spp. foram os visitantes mais frequentes. O comportamento e duração das visitas dessas abelhas variaram conforme o recurso coletado (i.e., pólen ou néctar). As espécies de Dialictus foram os polinizadores potenciais de J. montana, considerando sua frequência, contato com órgãos reprodutivos, e pelo fato de carregar apenas pólen de J. montana na superfície ventral do tórax, abdome e pernas. Embora não tenha sido quantificado, o néctar deve estar disponível até o final da tarde, considerando o comportamento das abelhas nas flores nesse período. A relação pólen:óvulo, no valor de 1.200:4, sugere a ocorrência de xenogamia facultativa.

How accessible are receptive megastrobili to pollen? the example of jack pine (Pinus banksiana).

We examined the effects of wind speeds on pollen capture by megastrobili of jack pine (Pinus banksiana). We found that, when wind speed increased from 1.3 to 7.5 m/s, the relative capture efficiency (E(r)) did not change significantly (P ≤ 0.206) and remained below 12%. However, total capture rates increased linearly with wind speed and atmospheric pollen density. Because theoretical models of capture efficiency predict the E(r) to increase to ∼80% asymptotically, our findings suggest that receptive megastrobili are equally adept at capturing pollen at all naturally occurring wind speeds.

Flower petal microtexture is a tactile cue for bees.

Honeybees are shown to be able to detect, learn, and discriminate between microsculptured epidermes of flower petals. The sensilla trichodea at the tips of the bees' antennae are in the same size range as the microsculptural features of the petals (ca. 10 mum), which presumably deflect these mechanoreceptive sensilla in characteristic ways. Honeybees were trained to associate reward with one floral texture and to choose that over another. Further, the bees also recognized differences in textures at different ends of petals of the same species. The phenomenon is significant in that it suggests another way in which insect pollinators can discriminate between the flowers of different plant species and so act as species isolators. Also, the microsculptural patterns differ from one end of a petal to the other and, therefore, can be used as nectar-guides by foraging bees. This study presents a previously unreported conditioned response to texture by insects and shows the functional significance of a floral character used in plant taxonomy.

The effect of shape parameters on maximal detection distance of model targets by honeybee workers.

The influence of several spatial parameters on the maximal detection distance of a target by approaching foraging honeybees was examined. The roles of target diameter, color and luminance contrasts have been already demonstrated in earlier studies. The present study used, for the first time, dissected flower like targets that differed in addition to diameter (D) and area (pi(D/2)(2) = Acir) also in the length of contour line (C), the area of the colored "petals" (Acol) and the degree of dissectedness as expressed mainly by the ratio Acol2/C. The color and luminance contrasts were identical for all targets. Our results confirm the importance of size. However, we demonstrate for the first time, that full circular shapes have the greatest maximal detection distance among targets of equal diameters, and even more than dissected targets with equal Acol and double D. The parameter Acol2/C was found as the best predictor of maximal detection distance of vertically presented targets with varying diameter and degree of dissection for honeybee workers. We propose that an increase in the colored area and decrease in contour line is advantageous due to the fact that it increases the amount of contrast that the target as a whole produces against its background.

Limits to the salience of ultraviolet: lessons from colour vision in bees and birds.

Ultraviolet is an important component of the photic environment. It is used by a wide variety of animals and plants in mutualistic communication, especially in insect and flower inter-relationships. Ultraviolet reflections and sensitivity are also becoming well considered in the relationships between vertebrates and their environment. The relative importance of ultraviolet vis à vis other primary colours in trichromatic or tetrachromatic colour spaces is discussed, and it is concluded that ultraviolet is, in most cases, no more important that blue, green or red reflections. Some animals may use specific wavebands of light for specific reactions, such as ultraviolet in escape or in the detection of polarised light, and other wavebands in stimulating feeding, oviposition or mating. When colour vision and, thus, the input from more than a single spectral receptor type are concerned, we point out that even basic predictions of signal conspicuousness require knowledge of the neuronal wiring used to evaluate the signals from all receptor types, including the ultraviolet. Evolutionary analyses suggest that, at least in arthropods, ultraviolet sensitivity is phylogenetically ancient and undergoes comparatively little evolutionary fine-tuning. Increasing amounts of ultraviolet in the photic environment, as caused by the decline of ozone in the atmosphere, are not likely to affect colour vision. However, a case for which ultraviolet is possibly unique is in the colour constancy of bees. Theoretical models predict that bees will perform poorly at identifying pure ultraviolet signals under conditions of changing illumination, which may explain the near absence of pure ultraviolet-reflecting flowers in nature.