scholarly journals Parasite Prevalence May Drive the Biotic Impoverishment of New England (USA) Bumble Bee Communities

Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 941
Author(s):  
Anne L. Averill ◽  
Andrea V. Couto ◽  
Jeremy C. Andersen ◽  
Joseph S. Elkinton

Numerous studies have reported a diversity of stressors that may explain continental-scale declines in populations of native pollinators, particularly those in the genus Bombus. However, there has been little focus on the identification of the local-scale dynamics that may structure currently impoverished Bombus communities. For example, the historically diverse coastal-zone communities of New England (USA) now comprise only a few species and are primarily dominated by a single species, B. impatiens. To better understand the local-scale factors that might be influencing this change in community structure, we examined differences in the presence of parasites in different species of Bombus collected in coastal-zone communities. Our results indicate that Bombus species that are in decline in this region were more likely to harbor parasites than are B. impatiens populations, which were more likely to be parasite-free and to harbor fewer intense infections or co-infections. The contrasting parasite burden between co-occurring winners and losers in this community may impact the endgame of asymmetric contests among species competing for dwindling resources. We suggest that under changing climate and landscape conditions, increasing domination of communities by healthy, synanthropic Bombus species (such as B. impatiens) may be another factor hastening the further erosion of bumble bee diversity.

2019 ◽  
pp. 1-34 ◽  
Author(s):  
Tracy A. Zarrillo ◽  
Kimberly A. Stoner

 With growing evidence of changes in local abundance, geographical range, and species diversity of wild bees, it is imperative to document wild bee communities in representative habitats throughout North America. The Connecticut shoreline has historically been subject to many natural and anthropogenic disturbances, and there is a lack of baseline data regarding bee biodiversity in Connecticut’s maritime habitats. In this study, we characterize the wild bee fauna of a discrete maritime habitat in Connecticut, USA, and examine salt-marsh, beach dune, and coastal scrub bee communities adjacent to Long Island Sound. Patterns found are discussed in relation to recent coastal surveys in New England. Biweekly surveys were conducted at Grass Island (Guilford, CT) over a two-year period (2011-2012) using pan traps and effort-based (timed) net collecting from flowers. A total of 3928 individual bees were collected, representing five families, 18 genera and at least 80 species. Floral records for 374 individuals resulted in associations of 35 bee species with 19 species of flowers. Seventy percent of the bees captured in the net survey were visiting alien plants, with the exotic Rosa rugosa Thunb. having the highest level of bee diversity and relative abundance. The total number of bee species collected in this survey represents approximately 23% of the known Connecticut fauna, including four specialists associated with coastal and wetland habitats. The abundance and diversity of bees visiting alien plants on Grass Island, as well as the occurrence of these sand specialists, may prove to be of conservation concern as the Connecticut shoreline continues to be altered.  


2001 ◽  
pp. 159-163 ◽  
Author(s):  
MARIKA Mänd ◽  
KALEV Sepp ◽  
JAAK Truu

Sociobiology ◽  
2018 ◽  
Vol 65 (4) ◽  
pp. 686 ◽  
Author(s):  
Laura Silva Nery ◽  
Juliana Toshie Takata ◽  
Bruna Bertagni De Camargo ◽  
Aryane Moreno Chaves ◽  
Patrícia Alves Ferreira ◽  
...  

Agriculture driven landscape changes has caused worldwide forest loss and fragmentation, seriously affecting biodiversity and ecosystem services, amongst which pollination is remarkably important. Bees are an essential pollinator group for forest plant populations and food production in tropical landscapes. They are also dependent on forested environments which are essential to maintain their diversity and pollination services. We analyzed bee diversity in contrasting forest and adjacent non-forest patches to evaluate if bees can use complementary non-native environments in heterogeneous altered tropical landscapes. The effect of landscape level heterogeneity and forest amount on bee diversity was also assessed. Our hypothesis was that bee communities would be more rich and diverse inside the forest understory, but due to supplementary foraging behaviors they would be more abundant in non-forested areas where flower availability is higher. We actively sampled bees visiting flowers within forest patches and in surrounding non-forest open areas between the Cantareira and Mantiqueira mountain ranges in São Paulo, Brazil. We found higher bee richness and diversity in open areas than in forest patches, partially denying our initial hypothesis but supporting that bees are more abundant in non-forest areas. We found strong indication that landscapes with higher amount of forest and environmental heterogeneity can provide more resources for bees through resource complementation processes, maintaining their diversity in the landscape. The presence of forest patches close to crop and open areas is of utmost importance for the conservation of bees and pollination services with important consequences for land management in tropical environments.


2004 ◽  
Vol 64 (1) ◽  
pp. 169-176 ◽  
Author(s):  
L. E. R. Tavares ◽  
J. L. Luque

Between March 2000 and April 2001, 63 specimens of N. barba from Angra dos Reis, coastal zone of the State of Rio de Janeiro (23°0'S, 44°19'W), Brazil, were necropsied to study their infracommunities of metazoan parasites. Fifteen species of metazoan parasites were collected: 2 digeneans, 1 monogenean, 2 cestodes, 1 acantocephalan, 2 nematodes, 6 copepods, and 1 hirudinean. Ninety-six percent of the catfishes were parasitized by at least one metazoan parasite species. A total of 646 individual parasites was collected, with mean of 10.3 ± 16.6 parasites/fish. The copepods were 37.5% of the total parasite specimens collected. Lepeophtheirus monacanthus was the most dominant species and the only species with abundance positively correlated with the host total length. Host sex did not influence parasite prevalence or mean abundance of any species. The mean diversity in the infracommunities of N. barba was H = 0.130 ± 0.115 with no correlation with host's total length and without differences in relation to sex of the host. One pair of endoparasites (Dinosoma clupeola and Pseudoacanthostomum floridensis) showed positive association and covariation between their abundances and prevalences. The parasite community of N. barba from Rio de Janeiro can be defined as a complex of species with low prevalence and abundance and with scarcity of interspecific associations. However, because of both the presence of assemblages of sympatric ariid species as well as the spawning behavior characteristic of these fishes, additional comparative studies of the parasite component communities of ariids are necessaries to elucidate this pattern.


2015 ◽  
Vol 12 (15) ◽  
pp. 4693-4709 ◽  
Author(s):  
X. Yue ◽  
N. Unger ◽  
T. F. Keenan ◽  
X. Zhang ◽  
C. S. Vogel

Abstract. Phenology is experiencing dramatic changes over deciduous forests in the USA. Estimates of trends in phenology on the continental scale are uncertain, however, with studies failing to agree on both the magnitude and spatial distribution of trends in spring and autumn. This is due to the sparsity of in situ records, uncertainties associated with remote sensing data, and the regional focus of many studies. It has been suggested that reported trends are a result of recent temperature changes, though multiple processes are thought to be involved and the nature of the temperature forcing remains unknown. To date, no study has directly attributed long-term phenological trends to individual forcings across the USA through integrating observations with models. Here, we construct an extensive database of ground measurements of phenological events across the USA, and use it to calibrate and evaluate a suite of phenology models. The models use variations of the accumulative temperature summation, with additional chilling requirements for spring phenology and photoperiod limitation for autumn. Including a chilling requirement or photoperiod limitation does not improve model performance, suggesting that temperature change, especially in spring and autumn, is likely the dominant driver of the observed trend during the past 3 decades. Our results show that phenological trends are not uniform over the contiguous USA, with a significant advance of 0.34 day yr−1 for the spring budburst in the east, a delay of 0.15 day yr−1 for the autumn dormancy onset in the northeast and west, but no evidence of change elsewhere. Relative to the 1980s, the growing season in the 2000s is extended by about 1 week (3–4 %) in the east, New England, and the upper Rocky Mountains forests. Additional sensitivity tests show that intraspecific variations may not influence the predicted phenological trends. These results help reconcile conflicting reports of phenological trends in the literature, and directly attribute observed trends to long-term changes in temperature.


Author(s):  
Alena Marcella Hantzschmann ◽  
Ulrich Sinsch ◽  
Christa Göttlicher ◽  
Heike Pröhl

AbstractAmphibian populations world-wide are threatened by declines and extinctions mainly due to habitat loss and fragmentation. Habitat fragmentation threatens the yellow-bellied toad Bombina variegata in the northern and western regions of its distribution where it is strictly protected. We studied the genetic structure and diversity of populations at three geographical scales using microsatellite loci to detect potential threats for population persistence. At the local scale, we sampled four neighbouring localities at 1–2.6 km distance to detect effects of short-term (decades) fragmentation on connectivity. At the regional scale, five additional localities in the mountains of the Westerwald (Rhineland-Palatinate, Germany) were studied at up to 50.1 km distance to analyse genetic diversity and population structure. At the continental scale, we included data from regions in the northern distribution with fragmented populations (Hesse and Lower Saxony, Germany) and more continuous populations in the South (Alsace, France; Geneva, Switzerland; Trentino, Italy) to evaluate variation of genetic diversity. At the local scale, short-term fragmentation caused significant genetic differentiation between breeding assemblages only 1.4 km apart from each other. At the regional scale, we found notable genetic distance among localities. At the continental scale, we identified Alsace, Trentino and Geneva in the South as regions with low genetic structuring and high allelic richness, and the northern remaining regions in Germany as deeply structured with reduced allelic richness. We suggest that reduced genetic diversity and habitat fragmentation in northern regions makes these populations particularly vulnerable to decline. In conclusion, informed conservation management of B. variegata should focus on measures maintaining or improving connectivity among neighbouring populations.


2021 ◽  
Vol 18 (1) ◽  
pp. 8-18
Author(s):  
O. Edo-Taiwo ◽  
M.S.O. Aisien

The parasitofauna of ground-dwelling anurans from pesticide-treated cocoa plantations (CP) in Ojo Camp, Ugboke, Edo State of Nigeria were investigated and compared with those recovered from host specimens collected from the village settlement (VS). The anurans were caught by hand following visual or acoustic location. The anurans encountered in both the VS and the CP included Aubria subsigillata, Hylarana spp. (H. albolabris and H. galamensis), Sclerophrys spp. (S. maculata and S. regularis), Ptychadena spp. (P. aequiplicata, P. longirostris, P. mascareniensis, P. oxyrhynchus and P. pumilio) and Hoplobatrachus occipitalis. Hylarana galamensis, Ptychadena spp. and Sclerophrys spp. were encountered in the VS and the CP while Aubria subsigillata, H. albolabris and H. occipitalis occurred only in the CP. The helminth parasites recovered included four cestode species (adult of Cylindrotaenia jaegerskioeldi and three encysted  proteocephalid larvae), five Polystoma spp. 11 species of digeneans and 19 nematode species. More parasite species were recovered from toads collected from the VS; parasite prevalence was generally low in both habitats but the intensity of infection was higher in the specimens collected from the VS. Although cip A. subsigillata and H. ocitalis both occurred in the CP, A. subsigillata was the more susceptible host of the two, harbouring 16 helminth parasites as against four from H. occipitalis. Polystomes were recovered from H. albolabris and H. galamensis in addition to Diplodiscus fischthalicus and Mesocoelium spp. Infections occurred  mostly among the Ptychadeniidae collected from the CP, with prevalence ranging from 12.5% to 100% and infection intensity from 1.0 to 13.0. The generally low parasite burden in anurans from the CP can possibly be attributed to the pesticide contamination of this habitat which may have hindered the development of the free-living stages of parasites in this milieu. Keywords: Anurans; cocoa plantation; pesticides; parasitofauna; prevalence; intensity.  


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