Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

The extent of our reliance on animal pollination for world crop production for human food has not previously been evaluated and the previous estimates for countries or continents have seldom used primary data. In this review, we expand the previous estimates using novel primary data from 200 countries and found that fruit, vegetable or seed production from 87 of the leading global food crops is dependent upon animal pollination, while 28 crops do not rely upon animal pollination. However, global production volumes give a contrasting perspective, since 60% of global production comes from crops that do not depend on animal pollination, 35% from crops that depend on pollinators, and 5% are unevaluated. Using all crops traded on the world market and setting aside crops that are solely passively self-pollinated, wind-pollinated or parthenocarpic, we then evaluated the level of dependence on animal-mediated pollination for crops that are directly consumed by humans. We found that pollinators are essential for 13 crops, production is highly pollinator dependent for 30, moderately for 27, slightly for 21, unimportant for 7, and is of unknown significance for the remaining 9. We further evaluated whether local and landscape-wide management for natural pollination services could help to sustain crop diversity and production. Case studies for nine crops on four continents revealed that agricultural intensification jeopardizes wild bee communities and their stabilizing effect on pollination services at the landscape scale.

/pdf/importance-of-pollinators-in-changing-landscapes-for-world-2j8o9ygr29.pdf

Importance of pollinators in changing landscapes for world crops

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.

/pdf/global-pollinator-declines-trends-impacts-and-drivers-5gfi4zur4k.pdf

Global pollinator declines: trends, impacts and drivers.

Bees are subject to numerous pressures in the modern world. The abundance and diversity of flowers has declined, bees are chronically exposed to cocktails of agrochemicals, and they are simultaneously exposed to novel parasites accidentally spread by humans. Climate change is likely to exacerbate these problems in the future. Stressors do not act in isolation; for example pesticide exposure can impair both detoxification mechanisms and immune responses, rendering bees more susceptible to parasites. It seems certain that chronic exposure to multiple, interacting stressors is driving honey bee colony losses and declines of wild pollinators, but such interactions are not addressed by current regulatory procedures and studying these interactions experimentally poses a major challenge. In the meantime, taking steps to reduce stress on bees would seem prudent; incorporating flower-rich habitat into farmland, reducing pesticide use through adopting more sustainable farming methods, and enforcing effective quarantine measures on bee movements are all practical measures that should be adopted. Effective monitoring of wild pollinator populations is urgently needed to inform management strategies into the future.

https://science.sciencemag.org/content/sci/early/2015/02/25/science.1255957.full.pdf

Bee declines driven by combined stress from parasites, pesticides, and lack of flowers

It is clear that the majority of fl owering plants are pollinated by insects and other animals, with a minority utilising abiotic pollen vectors, mainly wind. However there is no accurate published calculation of the proportion of the ca 352 000 species of angiosperms that interact with pollinators. Widely cited fi gures range from 67% to 96% but these have not been based on fi rm data. We estimated the number and proportion of fl owering plants that are pollinated by animals using published and unpublished community-level surveys of plant pollination systems that recorded whether each species present was pollinated by animals or wind. Th e proportion of animal-pollinated species rises from a mean of 78% in temperate-zone communities to 94% in tropical communities. By correcting for the latitudinal diversity trend in fl owering plants, we estimate the global number and proportion of animal pollinated angiosperms as 308 006, which is 87.5% of the estimated species-level diversity of fl owering plants. Given current concerns about the decline in pollinators and the possible resulting impacts on both natural communities and agricultural crops, such estimates are vital to both ecologists and policy makers. Further research is required to assess in detail the absolute dependency of these plants on their pollinators, and how this varies with latitude and community type, but there is no doubt that plant – pollinator interactions play a signifi cant role in maintaining the functional integrity of most terrestrial ecosystems. Plant – pollinator relationships may be one of the most ecologically important classes of animal – plant interaction: without pollinators, many plants could not set seed and reproduce; and without plants to provide pollen, nectar and other rewards, many animal populations would decline, with consequent knock-on eff ects for other species (Kearns et al.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0706.2010.18644.x

How many flowering plants are pollinated by animals

The anthophorid bee, Habropoda (= Emphoropsis [R. W. Brooks, personal communication]) laboriosa (F.), is a locally abundant, vernal, univoltine species. It flies from February through April in Georgia and Alabama. In these states, females are oligolectic on Vaccinium spp., particularly V. ashei Reade and V. corymbosum L., with Gelsemium sempervirens (L.), Quercus alba L., and Cercis canadensis L. as minor, alternate pollen hosts. Pollen-harvesting female H. laboriosa sonicate V. ashei flowers to release pollen, averaging 5.7 buzzes during their average 2.6-s floral visit, which is a handling rate 3 times faster than coforaging Bombus spp. Furthermore, mean floral handling rates of H. laboriosa females at V. ashei are individually more uniform than those of coforaging, polylectic Bombus spp., a hitherto undemonstrated but expected evolutionary outcome of oligolecty. Sonicated pollen accumulates on a ventral cephalic “safe site” of both sexes, which is the common site of V. ashei stigmatic contact. Floral probes are strictly legitimate (no robbing). Based upon its relative abundance at Vaccinium spp., phenology, floral handling behaviors and rates, and pollen preferences in the southeastern United States, we conclude that H. laboriosa is an oligolege adapted to species of Vaccinium for its pollen and nectar resources.

/pdf/foraging-ecology-of-the-bee-habropoda-laboriosa-hymenoptera-1hqcehwqaz.pdf

Foraging Ecology of the Bee Habropoda laboriosa (Hymenoptera: Anthophoridae), an Oligolege of Blueberries (Ericaceae: Vaccinium) in the Southeastern United States

Floral specialization by bees: analytical methodologies and a revised lexicon for oligolecty

Inadequate bee pollination limits rabbiteye blueberry,Vaccinium ashei Reade, production in the some areas of thesoutheastern United States Honey bees, Apis mellifera L,are currently the only manageable pollinators available for pollinatingV ashei However, a new adaptable pollinator for rabbiteyeblueberry, Osmia ribifloris Cockerell, was successfullyreared and flown in captivity The bee nested successfully in woodenshelters and conferred superior fruit set to 2-yr-old potted, rabbiteyeblueberry bushes Pollination efficiency or the percentage of blueberryflowers to set fruit after being visited once by a female Oribifloris was comparable to that of the female blueberry beeHabropoda laboriosa (F) and worker honey beesInterestingly, honey bees once thought to be inefficient pollinators ofrabbiteye blueberry were found to be very efficient, especially for‘Climax’ and ‘Premier’ flowers

Pollination efficiencies of three bee (Hymenoptera: Apoidea) species visiting rabbiteye blueberry.

An understanding of the evolutionary origins of insect foraging specialization is often hindered by a poor biogeographical and palaeoecological record. The historical biogeography (20000 years before present to the present) of the desert–limited plant, creosote bush ( Larrea tridentata ), is remarkably complete. This history coupled with the distribution pattern of its bee fauna suggests pollen specialization for creosote bush pollen has evolved repeatedly among bees in the Lower Sonoran and Mojave deserts. In these highly xeric, floristically depauperate environments, species of specialist bees surpass generalist bees in diversity, biomass and abundance. The ability of specialist bees to facultatively remain in diapause through resource–poor years and to emerge synchronously with host plant bloom in resource–rich years probably explains their ecological dominance and persistence in these areas. Repeated origins of pollen specialization to one host plant where bloom occurs least predictably is a counter–example to prevailing theories that postulate such traits originate where the plant grows best and blooms most reliably. Host–plant synchronization, a paucity of alternative floral hosts, or flowering attributes of creosote bush alone or in concert may account for the diversity of bee specialists that depend on this plant instead of nutritional factors or chemical coevolution between floral rewards and the pollinators they have evolved to attract.

Origins and ecological consequences of pollen specialization among desert bees

/pdf/origins-and-ecological-consequences-of-pollen-specialization-29lq2nx4nd.pdf

James H. Cane

Papers

Foraging Ecology of the Bee Habropoda laboriosa (Hymenoptera: Anthophoridae), an Oligolege of Blueberries (Ericaceae: Vaccinium) in the Southeastern United States

Floral specialization by bees: analytical methodologies and a revised lexicon for oligolecty

Pollination efficiencies of three bee (Hymenoptera: Apoidea) species visiting rabbiteye blueberry.

Origins and ecological consequences of pollen specialization among desert bees

Origins and ecological consequences of pollen specialization among desert bees.