Conservation Genetics of Potentially Endangered Mutualisms: Reduced Levels of Genetic Variation in Specialist versus Generalist Bees

Packer, Laurence; Zayed, Amro; Grixti, Jennifer C.; Ruz, Luisa; Owen, Robin E.; Vivallo, Felipe; Toro, Haroldo

doi:10.1111/j.1523-1739.2005.00601.x

Cited by 70 publications

(58 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Second, many species have high levels of resource specialization (29, 39, 46 -48). These aspects both serve to reduce effective population sizes and csd allelic richness (5,48). Third, eusocial species with large colony sizes have particularly low effective population sizes (5).…”

Section: Discussionmentioning

confidence: 99%

Complementary sex determination substantially increases extinction proneness of haplodiploid populations

Zayed

Packer

2005

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

275

312

View full text Add to dashboard Cite

The role of genetic factors in extinction is firmly established for diploid organisms, but haplodiploids have been considered immune to genetic load impacts because deleterious alleles are readily purged in haploid males. However, we show that singlelocus complementary sex determination ancestral to the haplodiploid Hymenoptera (ants, bees, and wasps) imposes a substantial genetic load through homozygosity at the sex locus that results in the production of inviable or sterile diploid males. Using stochastic modeling, we have discovered that diploid male production (DMP) can initiate a rapid and previously uncharacterized extinction vortex. The extinction rate in haplodiploid populations with DMP is an order of magnitude greater than in its absence under realistic but conservative demographic parameter values. Furthermore, DMP alone can elevate the base extinction risk in haplodiploids by over an order of magnitude higher than that caused by inbreeding depression in threatened diploids. Thus, contrary to previous expectations, haplodiploids are more, rather than less, prone to extinction for genetic reasons. Our findings necessitate a fundamental shift in approaches to the conservation and population biology of these ecologically and economically crucial insects.diploid male production ͉ haplodiploidy ͉ Hymenoptera ͉ pollinator decline ͉ conservation genetics H aplodiploid insects such as ants, bees, and wasps are crucial components of terrestrial ecosystems, and their conservation is essential for economic as well as ecological reasons (1-4). Despite the obvious differences that result from their sexdetermining mechanism, the conservation genetics of haplodiploids has received very little attention (5) and has been ignored in conservation efforts (6, 7). Inbreeding depression in diploid organisms significantly increases extinction risk (8-11), but faster purging of recessive deleterious mutations in haploid males is believed to render haplodiploids relatively immune to its effects (12-14), theoretically reducing their intrinsic extinction risk, compared with diploids. However, single-locus complementary sex determination (sl-CSD), ancestral in the Hymenoptera, introduces an unusual source of genetic load in small populations (15): the production of inviable or effectively sterile diploid males (DMs) from fertilized eggs homozygous at the sexdetermining locus, csd (16-19) (Fig. 1).Large haplodiploid populations can maintain many csd alleles (commonly 9-20 alleles; ref. 15) and thus have low levels of DM production (DMP). However, drift in small populations reduces csd allelic richness and increases DMP (15). Several studies have documented low levels of csd allelic richness (Ͻ5 alleles) in both natural and introduced populations (20-24). Because female hymenopterans fertilize their eggs to produce daughters only, the production of DMs effectively increases female mortality, thus reducing the potential for population growth (25) (Fig. 1). Further, DMP also reduces the effective breeding size of haplodiploids, espe...

show abstract

Section: Discussionmentioning

confidence: 99%

Complementary sex determination substantially increases extinction proneness of haplodiploid populations

Zayed

Packer

2005

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

275

312

View full text Add to dashboard Cite

show abstract

“…Because specialist bees have a more restricted foraging range, their effective population size (N e ) and levels of genetic variation are lowered, making these bees and pollination systems vulnerable and in need of protection. 30 …”

Section: Volume 113 | Number 9/10mentioning

confidence: 99%

Pollination: Impact, role-players, interactions and study – A South African perspective

Gous¹,

Willows‐Munro²,

Eardley³

et al. 2017

S. Afr. J. Sci.

View full text Add to dashboard Cite

Plant-pollinator interactions are essential for maintaining both pollinator and plant communities in native and agricultural environments. Animal-instigated pollination can be complex. Plants are usually visited by a number of different animal species, which in turn may visit flowers of several plant species. Therefore, the identification of the pollen carried by flower visitors is an essential first step in pollination biology. The skill and time required to identify pollen based on structure and morphology has been a major stumbling block in this field. Advances in the genetic analysis of DNA, using DNA barcoding, extracted directly from pollen offers an innovative alternative to traditional methods of pollen identification. This technique, which is reviewed in detail, can be used on pollen loads sampled from bees in the field and from specimens in historic collections. Here the importance of pollination, the role-players involved, their management and the evolution of their interactions, behaviour and morphology are reviewed -with a special focus on South African bees. Significance:• Pollen metabarcoding will enable the identification of pollen for a multitude of uses, including agriculture, conservation and forensics.• Plant-pollinator interaction documentation through pollen identification gives a more certain record of a visitor being a pollinator rather than a flower visitor that could be a nectar gatherer.

show abstract

“…Pollinators' ecological and economical value for long was contrasted by an incomplete understanding of pollinator population dynamics and genetics (e.g., Ghazoul 2005). Only recently this issue has been addressed in various conservation genetic studies especially on social bees (Kearns et al 1998;Packer et al 2005;Darvill et al 2006;Ellis et al 2006;Goulson et al 2008aGoulson et al , 2008bBrown and Paxton 2009;Grixti et al 2009;Murray et al 2009;Zayed 2009;Charman et al 2010). Bumblebees (Bombus spp.)…”

Section: Introductionmentioning

confidence: 99%

“…Insect mediated pollination is an essential but potentially endangered ecosystem function as numerous wild and managed pollinators have been reported to have undergone dramatic declines at a large scale (Packer et al 2005;Biesmeijer et al 2006). Pollinators' ecological and economical value for long was contrasted by an incomplete understanding of pollinator population dynamics and genetics (e.g., Ghazoul 2005).…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal dynamics of the male effective population size in bumblebees (Hymenoptera: Apidae)

et al. 2011

View full text Add to dashboard Cite

Eusociality and male haploidy of bumblebees (Bombus spp.) enhance the deleterious effects of population decline and aggravate the degeneration of population fitness compared to solitary and diploid species. The highly dispersive male sex may be the prime driver to connect otherwise isolated populations. We therefore studied the temporal and spatial structure of the male population of Bombus terrestris (Linnaeus 1758) and Bombus lapidarius (Linnaeus 1758) using microsatellite DNA markers. We found that the majority of the males in a 1000 m 2 sampling area originated from colonies located outside of the workers foraging range, which was consistent with the genetic distances among colonies. The analyses of temporal population sub-structure based on both colony detection rate over time and the clustering software STRUCTURE consistently suggested one large and temporally unstructured male population. Our results indicate an extended male flight distance for both species. Though the range of queen dispersal remains to be studied, the effective size (N e ) of bumblebees is increased by extended male mating flight ranges (A m ) exceeding worker foraging distance by factor 1.66 (A m = 69.75 km 2 ) and 1.74 (A m = 13.41 km 2 ), B. terrestris and B. lapidarius, respectively. Thus this behaviour may counteract genetic deprivation and its effects. All populations were genetically highly diverse and showed no signs of inbreeding. We discuss the implications of our findings in context of bumblebee population dynamics and conservation. We also highlight the effects and benefits of sampling both workers and males for population genetic studies.

show abstract

Conservation Genetics of Potentially Endangered Mutualisms: Reduced Levels of Genetic Variation in Specialist versus Generalist Bees

Cited by 70 publications

References 71 publications

Complementary sex determination substantially increases extinction proneness of haplodiploid populations

Complementary sex determination substantially increases extinction proneness of haplodiploid populations

Pollination: Impact, role-players, interactions and study – A South African perspective

Spatial and temporal dynamics of the male effective population size in bumblebees (Hymenoptera: Apidae)

Contact Info

Product

Resources

About