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Jermy T, Szentesi Á. Why are there not more herbivorous insect species? ACTA ZOOL ACAD SCI H 2021. [DOI: 10.17109/azh.67.2.119.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Insect species richness is estimated to exceed three million species, of which roughly half is herbivorous. Despite the vast number of species and varied life histories, the proportion of herbivorous species among plant-consuming organisms is lower than it could be due to constraints that impose limits to their diversification. These include ecological factors, such as vague interspecific competition; anatomical and physiological limits, such as neural limits and inability of handling a wide range of plant allelochemicals; phylogenetic constraints, like niche conservatism; and most importantly, a low level of concerted genetic variation necessary to a phyletic conversion. It is suggested that diversification ultimately depends on what we call the intrinsic trend of diversification of the insect genome. In support of the above, we survey the major types of host-specificity, the mechanisms and constraints of host specialization, possible pathways of speciation, and hypotheses concerning insect diversification.
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Hippee AC, Beer MA, Bagley RK, Condon MA, Kitchen A, Lisowski EA, Norrbom AL, Forbes AA. Host shifting and host sharing in a genus of specialist flies diversifying alongside their sunflower hosts. J Evol Biol 2020; 34:364-379. [PMID: 33190382 DOI: 10.1111/jeb.13740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/02/2020] [Accepted: 10/30/2020] [Indexed: 11/30/2022]
Abstract
Congeneric parasites are unlikely to specialize on the same tissues of the same host species, likely because of strong multifarious selection against niche overlap. Exceptions where >1 congeneric species use the same tissues reveal important insights into ecological factors underlying the origins and maintenance of diversity. Larvae of sunflower maggot flies in the genus Strauzia feed on plants in the family Asteraceae. Although Strauzia tend to be host specialists, some species specialize on the same hosts. To resolve the origins of host sharing among these specialist flies, we used reduced representation genomic sequencing to infer the first multilocus phylogeny of genus Strauzia. Our results show that Helianthus tuberosus and Helianthus grosseserratus each host three different Strauzia species and that the flies co-occurring on a host are not one another's closest relatives. Though this pattern implies that host sharing is most likely the result of host shifts, these may not all be host shifts in the conventional sense of an insect moving onto an entirely new plant. Many hosts of Strauzia belong to a clade of perennial sunflowers that arose 1-2 MYA and are noted for frequent introgression and hybrid speciation events. Our divergence time estimates for all of the Helianthus-associated Strauzia are within this same time window (<1 MYA), suggesting that rapid and recent adaptive introgression and speciation in Helianthus may have instigated the diversification of Strauzia, with some flies converging upon a single plant host after their respective ancestral host plants hybridized to form a new sunflower species.
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Affiliation(s)
- Alaine C Hippee
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | - Marc A Beer
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Robin K Bagley
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University at Lima, Lima, OH, USA
| | - Marty A Condon
- Department of Biology, Cornell College, Mount Vernon, IA, USA
| | - Andrew Kitchen
- Department of Anthropology, University of Iowa, Iowa City, IA, USA
| | | | - Allen L Norrbom
- Systematic Entomology Laboratory, USDA, ARS, PSI, c/o National Museum of Natural History, Washington, DC, USA
| | - Andrew A Forbes
- Department of Biology, University of Iowa, Iowa City, IA, USA
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Leppänen J, Seppä P, Vepsäläinen K, Savolainen R. Genetic divergence between the sympatric queen morphs of the antMyrmica rubra. Mol Ecol 2015; 24:2463-76. [DOI: 10.1111/mec.13170] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 01/09/2023]
Affiliation(s)
- Jenni Leppänen
- Department of Biosciences; University of Helsinki; P.O. Box 65 Helsinki 00014 Finland
| | - Perttu Seppä
- Centre of Excellence in Biological Interactions; Department of Biosciences; University of Helsinki; P.O. Box 65 Helsinki 00014 Finland
| | - Kari Vepsäläinen
- Department of Biosciences; University of Helsinki; P.O. Box 65 Helsinki 00014 Finland
| | - Riitta Savolainen
- Department of Biosciences; University of Helsinki; P.O. Box 65 Helsinki 00014 Finland
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