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Raine EH, Slade EM. Dung beetle-mammal associations: methods, research trends and future directions. Proc Biol Sci 2019; 286:20182002. [PMID: 30963853 PMCID: PMC6408906 DOI: 10.1098/rspb.2018.2002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Dung beetles are increasingly used as a study taxon—both as bioindicators of environmental change, and as a model system for exploring ecosystem functioning. The advantages of this focal taxon approach are many; dung beetles are abundant in a wide range of terrestrial ecosystems, speciose, straightforward to sample, respond to environmental gradients and can be easily manipulated to explore species-functioning relationships. However, there remain large gaps in our understanding of the relationship between dung beetles and the mammals they rely on for dung. Here we review the literature, showing that despite an increase in the study of dung beetles linked to ecosystem functioning and to habitat and land use change, there has been little research into their associations with mammals. We summarize the methods and findings from dung beetle–mammal association studies to date, revealing that although empirical field studies of dung beetles rarely include mammal data, those that do, indicate mammal species presence and composition has a large impact on dung beetle species richness and abundance. We then review the methods used to carry out diet preference and ecosystem functioning studies, finding that despite the assumption that dung beetles are generalist feeders, there are few quantitative studies that directly address this. Together this suggests that conclusions about the effects of habitat change on dung beetles are based on incomplete knowledge. We provide recommendations for future work to identify the importance of considering mammal data for dung beetle distributions, composition and their contributions to ecosystem functioning; a critical step if dung beetles are to be used as a reliable bioindicator taxon.
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Affiliation(s)
- Elizabeth H Raine
- 1 Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS , UK
| | - Eleanor M Slade
- 1 Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS , UK.,2 Lancaster Environment Centre, University of Lancaster , Lancaster LA1 AYQ , UK
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Franzini PZN, Ramond JB, Scholtz CH, Sole CL, Ronca S, Cowan DA. The Gut Microbiomes of Two Pachysoma MacLeay Desert Dung Beetle Species (Coleoptera: Scarabaeidae: Scarabaeinae) Feeding on Different Diets. PLoS One 2016; 11:e0161118. [PMID: 27532606 PMCID: PMC4988786 DOI: 10.1371/journal.pone.0161118] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/29/2016] [Indexed: 12/13/2022] Open
Abstract
Micro-organisms inhabiting animal guts benefit from a protected and nutrient-rich environment while assisting the host with digestion and nutrition. In this study we compare, for the first time, the bacterial and fungal gut communities of two species of the small desert dung beetle genus Pachysoma feeding on different diets: the detritivorous P. endroedyi and the dry-dung-feeding P. striatum. Whole-gut microbial communities from 5 individuals of each species were assessed using 454 pyrosequencing of the bacterial 16S rRNA gene and fungal ITS gene regions. The two bacterial communities were significantly different, with only 3.7% of operational taxonomic units shared, and displayed intra-specific variation. The number of bacterial phyla present within the guts of P. endroedyi and P. striatum individuals ranged from 6-11 and 4-7, respectively. Fungal phylotypes could only be detected within the gut of P. striatum. Although the role of host phylogeny in Pachysoma microbiome assembly remains unknown, evidence presented in this study suggests that host diet may be a deterministic factor.
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Affiliation(s)
- Philippa Z. N. Franzini
- Centre for Microbial Ecology and Genomics, Genomic Research Institute, Department of Genetics, University of Pretoria, Pretoria, South Africa
| | - Jean-Baptiste Ramond
- Centre for Microbial Ecology and Genomics, Genomic Research Institute, Department of Genetics, University of Pretoria, Pretoria, South Africa
| | - Clarke H. Scholtz
- Scarab Research Group, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Catherine L. Sole
- Scarab Research Group, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Sandra Ronca
- Centre for Microbial Ecology and Genomics, Genomic Research Institute, Department of Genetics, University of Pretoria, Pretoria, South Africa
| | - Don A. Cowan
- Centre for Microbial Ecology and Genomics, Genomic Research Institute, Department of Genetics, University of Pretoria, Pretoria, South Africa
- * E-mail:
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Estes AM, Hearn DJ, Snell-Rood EC, Feindler M, Feeser K, Abebe T, Dunning Hotopp JC, Moczek AP. Brood ball-mediated transmission of microbiome members in the dung beetle, Onthophagus taurus (Coleoptera: Scarabaeidae). PLoS One 2013; 8:e79061. [PMID: 24223880 PMCID: PMC3815100 DOI: 10.1371/journal.pone.0079061] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 09/17/2013] [Indexed: 01/30/2023] Open
Abstract
Insects feeding on plant sap, blood, and other nutritionally incomplete diets are typically associated with mutualistic bacteria that supplement missing nutrients. Herbivorous mammal dung contains more than 86% cellulose and lacks amino acids essential for insect development and reproduction. Yet one of the most ecologically necessary and evolutionarily successful groups of beetles, the dung beetles (Scarabaeinae) feeds primarily, or exclusively, on dung. These associations suggest that dung beetles may benefit from mutualistic bacteria that provide nutrients missing from dung. The nesting behaviors of the female parent and the feeding behaviors of the larvae suggest that a microbiome could be vertically transmitted from the parental female to her offspring through the brood ball. Using sterile rearing and a combination of molecular and culture-based techniques, we examine transmission of the microbiome in the bull-headed dung beetle, Onthophagus taurus. Beetles were reared on autoclaved dung and the microbiome was characterized across development. A ~1425 bp region of the 16S rRNA identified Pseudomonadaceae, Enterobacteriaceae, and Comamonadaceae as the most common bacterial families across all life stages and populations, including cultured isolates from the 3rd instar digestive system. Finer level phylotyping analyses based on lepA and gyrB amplicons of cultured isolates placed the isolates closest to Enterobacter cloacae, Providencia stuartii, Pusillimonas sp., Pedobacter heparinus, and Lysinibacillus sphaericus. Scanning electron micrographs of brood balls constructed from sterile dung reveals secretions and microbes only in the chamber the female prepares for the egg. The use of autoclaved dung for rearing, the presence of microbes in the brood ball and offspring, and identical 16S rRNA sequences in both parent and offspring suggests that the O. taurus female parent transmits specific microbiome members to her offspring through the brood chamber. The transmission of the dung beetle microbiome highlights the maintenance and likely importance of this newly-characterized bacterial community.
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Affiliation(s)
- Anne M. Estes
- Towson University, Department of Biological Sciences, Baltimore, Maryland, United States of America
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| | - David J. Hearn
- Towson University, Department of Biological Sciences, Baltimore, Maryland, United States of America
- J. Craig Venter Institute, Inc., Plant Genomics, Rockville, Maryland, United States of America,
| | - Emilie C. Snell-Rood
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Michele Feindler
- Towson University, Department of Biological Sciences, Baltimore, Maryland, United States of America
| | - Karla Feeser
- Towson University, Department of Biological Sciences, Baltimore, Maryland, United States of America
| | - Tselotie Abebe
- Towson University, Department of Biological Sciences, Baltimore, Maryland, United States of America
| | - Julie C. Dunning Hotopp
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Armin P. Moczek
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
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