Presence Of Honey Bees Research Articles

The effect of introduced honeybees on native bee visitation and fruit-set in Dillwynia juniperina (Fabaceae) in a fragmented ecosystem

The endemic shrub Dillwynia juniperina is found in fragmented woodlands on the Northern Tablelands of New South Wales, Australia. The species obligatorily relies on pollinators to effect fruit-set and in this study the effect of fragmentation and the presence of the introduced honeybee on fruit-set was examined at two locations. Over two seasons Dillwynia juniperina was not pollen-limited indicating that flowers were saturated with pollen and that adequate bee servicing was occurring. Two native bee species ( Leioproctus sp. 1 and Lasioglossum sp.) and the introduced honeybee, Apis mellifera L., were the most common visitors to flowers. Bee abundance varied between sites with honeybees being more common than native bees at one site. Native bees were never the most dominant pollinator. Visitation data show that native bees spend more time at flowers than introduced bees, although on average honeybees visit slightly more flowers on a bush than do native bees. Visitation data also revealed that native bee presence at bushes is negatively correlated with the presence of honeybees at the same bushes. At one of the study sites, honeybees were very abundant, but very few native bees were ever recorded over the 3 years. Results show that flowers can be pollinated from a single visit by a honeybee or native bee. Extrapolation of visitation data showed that native bees could on their own adequately service flowers in some years at some sites while at other times introduced honeybees may be necessary to augment pollination services.

Honey Bees (Hymenoptera: Apidae) as Vectors ofBacillus thuringiensisfor Control of Banded Sunflower Moth (Lepidoptera: Tortricidae)

A study was conducted in 1996 and 1997 to determine if honey bees, Apis mellifera L., could vector Bacillus thuringiensis Berliner variety kurstaki from hives equipped with a pathogen applicator to sunflower capitula and if the amount of B. thuringiensis deposited on the capitula would be sufficient to control the banded sunflower moth, Cochylis hospes Walsingham. The study dem- onstrated that honey bees became contaminated with B. thuringiensis as they exited hives equipped with filled pathogen applicators and deposited enough B. thuringiensis on the capitula to cause banded sunflower moth larval mortality. When 2 methods of applying B. thuringiensis were com- pared, the honey bee vectoring method gave better or equivalent control of the banded sunflower moth larvae than manual sprays, resulting in higher seed yields than manual sprays. The presence of honey bees also increased seed set which contributed to greater yield.

216 Squash Pollination by Honey Bees vs. Native Pollinators in Maine

Managed and feral honey bee (Apis mellifera) colonies have declined dramatically in the past decade due largely to parasitic mites, pesticide contamination, and severe weather. Squash (Cucurbita spp.) is one of many agricultural crops whose production may be negatively effected by decline of these pollinators. A study was conducted on a set of nine farms in Maine to assess the relationship between bee abundance and fruit set of summer and winter squash. The organic and conventional farms targeted in the study included farms with and without the presence of honey bees. With winter squash, fields with more bees tended to exhibit higher fruit set. The average fruit set was slightly higher for farms with honey bees (42%) vs. those without (35%), but both types of farms were similar to that found in controlled hand pollinations (31% on average). In contrast, fruit set for summer squash averaged 95% to 96% for all farms, regardless of the relative abundance of censused bees. Bumble bees (Bombus spp.) were the most abundant wild bees found pollinating squash. Farms with honey bees on average had higher numbers of bees in squash flowers than farms without honey bees, although a difference in preference for floral sex type was detected for bee taxa. Honey bees were much more likely to be found in female flowers, while bumble bees were more abundant in male flowers. Significantly more native bees were found in squash flowers on farms without honey bee hives, although native bees were still present to some extent on farms that were dominated by Apis mellifera.

Visits of Honeybees (Hymenoptera: Apidae) and their Effects on Cucumber Yields in the Field

Field tests were conducted to determine whether the presence of honey bees ( Apis mellifera L.), as well as the number and duration of their visits to flowers affected cucumber ( Cucumis sativus L.) yields. The experiment included flowers not visited by bees, flowers freely visited by bees, and flowers with controlled visits by bees. A single visit to a flower was sufficient to induce fruiting. Flowers that had the greatest number of visits and highest cumulative durations of visits also had the greatest cucumber yields. The rate of pollination was correlated with the cumulative duration but not with the total number of bee visits. The maximum cucumber circumference was significantly correlated with the cumulative duration of bee visits. No significant correlation was found between cucumber weight and the number or cumulative duration of visits by bees. The presence of honey bees together with the number and cumulative duration of their visits to the flowers are important to pollination and influence both the quality and the quantity of cucumber production.

Ecological Impacts of Introduced Honey Bees

Honey bees (Apis mellifera L.), native to Eurasia and Africa, have been introduced to most of the rest of the world. Many plant species are used by introduced honey bees, which suggests a high potential for disturbance of native plant/pollinator relationships. Few species are used intensively, however, thus decreasing the opportunity for disturbance. Pollination studies show that honey bees are effective pollinators of some native plants and less effective pollinators of others; they also reduce floral resources in some species with little or no pollination. Data are insufficient to show whether honey bee foraging on native plants significantly alters pollen and gene flow, but unusual foraging behavior by honey bees is not evident compared to many other pollinators. Honey bees do not physically damage plants; they are also unlikely to increase hybridization of native flora. Pollination by honey bees probably contributes little to the success of most weeds. Experiments have not shown competition for nesting sites between honey bees and native fauna. The presence of honey bees, however, alters the foraging behavior and abundance of some native fauna on flowers, but no studies have shown detrimental impacts of honey bees on population abundances of any native animals or plants. Anecdotal and quantitative reports of increased honey bee abundances on flowers compared with native fauna are often confounded with habitat changes induced by man.

Outcrossing in Aeschynomene

Plant breeders shape breeding and seed increase programs, in part, according to the percent outcrossing in the species. Previous reports indicated that aeschynomene, Aeschynomene americana L., was almost entirely self‐pollinated. The objective of these experiments was to determine percent outcrossing under greenhouse and field conditions. A completely dominant trait, glabrousness, was used to determine percent outcrossing in a pubescent line of aeschynomene in the presence of honey bees, Apis spp., in the greenhouse and natural pollinators in the field. Mean percent outcrossing during two seasons in the greenhouse was 24%. Mean percent outcrossing was 30% at two Florida locations separated by 450 km. This level of outcrossing suggests that more rigorous isolation requirements than those currently used may be needed in breeding programs and seed increase fields where two or more lines are grown nearby.

A review of kiwifruit pollination: Where to next?

Abstract The likely role of various pollination vectors is considered in the context of flower anatomy and the published results of past experiments. A number of insects visit flowers of both female and male vines but there is as much evidence implicating wind as there is for an insect vector. Most experiments that investigated a likely role of wind alter wind flows and are confounded by the presence of honey bees. Similarly, evidence taken as support for the role of honey bees is confounded by the action of wind. Recent studies suggest that individual bees tend to work the flowers of one sex of vine or the other. Existing methods of measuring pollination effectiveness in kiwifruit are also questioned as is our understanding of incompatibility responses. An experiment that can help resolve these problems is outlined briefly.

Pollination of Raspberries by Honeybees

SummaryRaspberry plants which were caged in the field produced fewer and smaller berries than uncaged ones. The fruit had 71–82% fewer drupelets in the absence than in the presence of honeybees, whether in still air or in a wind (4 or 11 km/hr).

The Pollination of Mustard by Honeybees

SUMMARYThe presence of honeybees in bee-proof cages put over plots of mustard substantially increased the seed yield of Brassica alba, but not that of B. juncea.

The Influence of Honey Bees on the Production of Crimson Clover Seed1

Experiments were conducted in Alabama from 1951 through 1954 to determine the influence of the honey bee, A pis mellifera L., on the yield of seed of crimson clover, Trifolium incarnatum L. Colonies of bees were available in known concentrations to crimson clover fields. Observations were made during the blooming period of the clover to determine the condition of the clover plants and the number of bees visiting the clover. Cages were used to exclude the bees from small plots of blooming clover, and yields of seed from these plots were compared with those from adjacent areas to which the bees had access. The presence of honey bees resulted in highly significant increases in seed yields of crimson clover. Under ordinary field conditions in Alabama, two colonies of bees per acre of crimson clover resulted in most efficient seed production. The average gains in total yield of seed per acre where bees were present at a rate of two colonies per acre over the yields where bees were excluded were from 281 to 509 pounds. Where the best agronomic practices were followed, the gain in total yield of seed using three colonies of bees per acre was 1019 pounds, or a gain in yield by combine harvest of more than 800 pounds. The number of pods formed in the clover heads was not affected by the various treatments. The percentage of the pods that contained seed was in direct proportion to seed yields. The reduction of wind or shade as caused by cages or partial cages in the clover plots had only a minor effect on yield of seed of crimson clover.