Pollinators are a key component of global biodiversity, providing vital ecosystem services to crops and wild plants. There is clear evidence of recent declines in both wild and domesticated pollinators, and parallel declines in the plants that rely upon them. Here we describe the nature and extent of reported declines, and review the potential drivers of pollinator loss, including habitat loss and fragmentation, agrochemicals, pathogens, alien species, climate change and the interactions between them. Pollinator declines can result in loss of pollination services which have important negative ecological and economic impacts that could significantly affect the maintenance of wild plant diversity, wider ecosystem stability, crop production, food security and human welfare.

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Global pollinator declines: trends, impacts and drivers.

http://www.tsusinvasives.org/dotAsset/3b275f2a-205c-4012-b48a-038a13dddf8f.pdf

Biology and control of Varroa destructor

Wild and managed bees are well documented as effective pollinators of global crops of economic importance. However, the contributions by pollinators other than bees have been little explored despite their potential to contribute to crop production and stability in the face of environmental change. Non-bee pollinators include flies, beetles, moths, butterflies, wasps, ants, birds, and bats, among others. Here we focus on non-bee insects and synthesize 39 field studies from five continents that directly measured the crop pollination services provided by non-bees, honey bees, and other bees to compare the relative contributions of these taxa. Non-bees performed 25–50% of the total number of flower visits. Although non-bees were less effective pollinators than bees per flower visit, they made more visits; thus these two factors compensated for each other, resulting in pollination services rendered by non-bees that were similar to those provided by bees. In the subset of studies that measured fruit set, fruit set increased with non-bee insect visits independently of bee visitation rates, indicating that non-bee insects provide a unique benefit that is not provided by bees. We also show that non-bee insects are not as reliant as bees on the presence of remnant natural or seminatural habitat in the surrounding landscape. These results strongly suggest that non-bee insect pollinators play a significant role in global crop production and respond differently than bees to landscape structure, probably making their crop pollination services more robust to changes in land use. Non-bee insects provide a valuable service and provide potential insurance against bee population declines.

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Non-bee insects are important contributors to global crop pollination

Growing evidence indicates that European managed honey bees are in decline, but information for Europe remains patchy and localized. Here we compile data from 18 European countries to assess trends in the number of honey bee colonies and beekeepers between 1965 and 2005. We found consistent declines in colony numbers in central European countries and some increases in Mediterranean countries. Beekeeper numbers have declined in all of the European countries examined. Our data support the view that honey bees are in decline at least in some regions, which is probably closely linked to the decreasing number of beekeepers. Our data on colony numbers and beekeepers must, however, be interpreted with caution due to different approaches and socioeconomic factors in the various countries, thereby limiting their comparability. We therefore make specific recommendations for standardized methodologies to be adopted at the national and global level to assist in the future monitoring of honey bees.

/pdf/declines-of-managed-honey-bees-and-beekeepers-in-europe-5ai5zckyyb.pdf

Declines of managed honey bees and beekeepers in Europe

In an age of accelerating biodiversity loss, this timely and critical volume summarizes recent advances in biodiversity-ecosystem functioning research and explores the economics of biodiversity and ecosystem services. The book starts by summarizing the development of the basic science and provides a meta-analysis that quantitatively tests several biodiversity and ecosystem functioning hypotheses. It then describes the natural science foundations of biodiversity and ecosystem functioning research including: quantifying functional diversity, the development of the field into a predictive science, the effects of stability and complexity, methods to quantify mechanisms by which diversity affects functioning, the importance of trophic structure, microbial ecology, and spatial dynamics. Finally, the book takes research on biodiversity and ecosystem functioning further than it has ever gone into the human dimension, describing the most pressing environmental challenges that face humanity and the effects of diversity on: climate change mitigation, restoration of degraded habitats, managed ecosystems, pollination, disease, and biological invasions.However, what makes this volume truly unique are the chapters that consider the economic perspective. These include a synthesis of the economics of ecosystem services and biodiversity, and the options open to policy-makers to address the failure of markets to account for the loss of ecosystem services; an examination of the challenges of valuing ecosystem services and, hence, to understanding the human consequences of decisions that neglect these services; and an examination of the ways in which economists are currently incorporating biodiversity and ecosystem functioning research into decision models for the conservation and management of biodiversity. A final section describes new advances in ecoinformatics that will help transform this field into a globally predictive science, and summarizes the advancements and future directions of the field. The ultimate conclusion is that biodiversity is an essential element of any strategy for sustainable development.

Biodiversity, Ecosystem Functioning, and Human Wellbeing: An Ecological and Economic Perspective

We studied the spread of the newly introduced parasitic mite, Varma jacobsoni Oudemans, within California's population of the feral honey bee, Apis mellifera L. , by examining worker bees taken from 208 colonies in 1990, 124 of which were examined again in 1993. The samples taken in 1990 did not contain V. jacobsoni mites. In 1993, 75% of the colonies examined in an area located near Sacramento, CA, no longer existed, and all surviving colonies were infested with V. jacobsoni . In an area located near the Californian central coast, 84% of the nest sites examined were occupied and few colonies contained detectable levels of V. jacobsoni . The probability of survival for colonies that have not survived a winter yet (founder colonies) has been previously reported to be low in areas with a temperate climate. Data collected in an area with a low level of Varroa mite infestation suggest that the probability of founder colony survival is higher in California with a mostly Mediterranean climate. The data collected in areas with a high level of Varroa mite infestation suggest that the parasite reduces the mean life span of feral honey bee colonies in California to go between 6 mo and 1 yr. The parasite was widely spread in areas with a high density of commercial colonies. This suggests that the fast spread of the parasite is caused mostly by migration of commercial colonies. We discuss the consequences of the decline of the feral honey bee population on pollination and on the invasion of California by Africanized bees.

Effect of Varroa jacobsoni (Mesostigmata: Varroidae) on Feral Apis mellifera (Hymenoptera: Apidae) in California

SUMMARYVarroa jacobsoni kept on honey bees of different ages for 3–5 days were tested in simultaneous choice tests. Comparisons of attractiveness to V. jacobsoni were made between nurse bees and pollen foragers as well as between nurse bees and larvae from nearly capped brood cells. Choices were presented in petri dishes and in a Y-shaped olfactometer. All tested V. jacobsoni groups showed a clear preference for nurse bees compared to bee brood (4 groups) or a trend towards preferring nurse bees (2 groups). The preference was less pronounced in the olfactometer tests than in the petri dish tests. The simultaneous choice tests between nurse bees and pollen foragers led to very similar results with both test methods. V. jacobsoni which had been kept on nurse bees showed a clear preference for nurse bees. V. jacobsoni which had been kept on pollen foragers did not distinguish between nurse bees and pollen foragers.

Preferences of Varroa jacobsoni for honey bees (Apis mellifera L.) of different ages

Three groups of bee colonies were treated with lactic acid, the pesticide Perizin or lactic acid and Perizin in order to validate the applicability of lactic acid in Varroa mite control. The lactic acid treatment was conducted during winter. Eight ml of lactic acid (15%) per comb side were applied with a dosage gun. The treatment was highly efficient and 94.2%–99.8% of the mites in a colony were killed. Due to precise dosage the lactic acid treatment caused less bee mortality than a treatment with the pesticide Perizin. A lactic acid treatment at-0.2°C caused bee mortality comparable to a Perizin treatment. The number of queen losses after lactic acid treatment and after Perizin treatment was comparable. The number of bees, the size of the brood area, the amount of stored honey and Nosema infestation rates were not significantly different in lactic acid treated colonies and Perizin treated colonies in spring after treatment.

Effect of a lactic acid treatment during winter in temperate climate upon Varroa jacobsoni Oud. and the bee (Apis mellifera L.) colony

Reproducing Varroa jacobsoni obtained from brood cells of Apis mellifera L. with 13–16 day old bees (pupae) and Varroa mites kept on adult bees for at least 8 days were simultaneously tested for their choice in three host types. Comparisons were made of attractiveness of Varroa jacobsoni to nurse bees, pollen foragers as to larvae from nearly capped brood cells. Host choices were observed in Petri dishes and in an Y-shaped olfactometer. Varroa jacobsoni obtained from capped brood cells showed a stronger preference for nurse bees in Petri dish simultaneous choice tests with pollen foragers or larvae than did mites which were previously kept on adult bees. In olfactometer simultaneous choice tests, the two mite test groups showed no clear difference in preferences for bees of different ages. The preference of Varroa jacobsoni for bees of different ages is therefore not only influenced by host factors but also by intrinsic factors in female mites that depend on the mite's reproductive stage.

Bernhard Kraus

Papers

Effect of Varroa jacobsoni (Mesostigmata: Varroidae) on Feral Apis mellifera (Hymenoptera: Apidae) in California

Preferences of Varroa jacobsoni for honey bees (Apis mellifera L.) of different ages

Effect of a lactic acid treatment during winter in temperate climate upon Varroa jacobsoni Oud. and the bee (Apis mellifera L.) colony

Factors influencing host choice of the honey bee parasite Varroa jacobsoni Oud

Effect of colony odour upon attractiveness of bees (Apis mellifera) of same ages for Varroa jacobsoni.