Morphological and Chemical Evidence on the Hybrid Nature of Bitter Pecan, Carya x Lecontei

Host‐associated differentiation (HAD) is the formation of genetically divergent host‐associated sub‐populations. Evidence of HAD has been reported for multiple insect herbivores to date, but published studies testing more than one herbivore for any given host‐plant species pair is limited to herbivores on goldenrods. This limits the number of pair‐wise comparisons that can be made about insect life‐history traits that might facilitate or inhibit host‐race development in general. Two traits previously proposed to facilitate HAD include endophagy and parthenogenesis. We tested for HAD in two herbivores, a quasi‐endophagous caterpillar and a parthenogenetic aphid, feeding on two closely related species of hickories. We found that the quasi‐endophage is panmictic, whereas the parthenogen exhibits HAD on their sympatric host plants, pecan and water hickory, at a geographic mesoscale. This is an important first step in the characterization of HAD in multiple insect herbivores using North American hickories, a host‐plant system with many shared parthenogens.

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“…, 2003). Water hickory is a species closely related to pecan but unlike pecan has a flat, wrinkled and bitter nut (Stone et al. , 1965).…”

Section: Methodsmentioning

confidence: 99%

“…Phenological differences between host plants have been shown to be important sources of ecological isolation of insect populations in sympatry (Komatsu & Akimoto, 1995; Feder & Filchak, 1999; Mopper, 2005), which could drive HAD. Despite phenological differences, pecan and water hickory hybridize in the wild (Stone et al. , 1965; Grauke et al.…”

Section: Methodsmentioning

confidence: 99%

Testing host‐associated differentiation in a quasi‐endophage and a parthenogen on native trees

Dickey

Medina

2010

J of Evolutionary Biology

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“…These tree species occur along river and creek bottoms in hardwood forests of eastern North America (Fralish & Franklin, 2002). Water hickory is a closely related species to pecan (Stone et al. , 1964).…”

Section: Introductionmentioning

confidence: 99%

Differences in bacterial diversity of host-associated populations of Phylloxera notabilis Pergande (Hemiptera: Phylloxeridae) in pecan and water hickory

Medina

Nachappa

Tamborindeguy

2011

Journal of Evolutionary Biology

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Host‐associated differentiation (HAD) is the presence of genetically divergent, host‐associated populations. It has been suggested that microbial symbionts of insect herbivores may play a role in HAD by allowing their insect hosts to use different plant species. The objective of this study was to document if host‐associated populations of Phylloxera notabilis Pergande (Hemiptera: Phylloxeridae) in pecan and water hickory corresponded with differences in the composition of their associated bacteria. To test this hypothesis, we characterized the symbionts present in P. notabilis associated with these two tree species through metagenomic analyses using 454 sequencing. Differences in bacterial diversity were found between P. notabilis populations associated with pecan and water hickory. The bacteria, Pantoea agglomerans and Serratia marcescens, were absent in the P. notabilis water hickory population, whereas both species accounted for more than 69.72% of bacterial abundance in the pecan population.

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“…However, C. aquatica and C. illinoinensis have been grouped together in the clade Apocarya (Thompson & Grauke, ). Pecan and water hickory can be differentiated based on nut morphology; pecan has a rounded, fleshy, and sweet nut, whereas water hickory has a flattened, wrinkled, and bitter nut (Stone et al., ). Despite being phenologically distinct, pecan and water hickory hybridize in the wild (Stone et al., ; Grauke et al., ).…”

Section: Methodsmentioning

confidence: 99%

“…Pecan and water hickory can be differentiated based on nut morphology; pecan has a rounded, fleshy, and sweet nut, whereas water hickory has a flattened, wrinkled, and bitter nut (Stone et al., ). Despite being phenologically distinct, pecan and water hickory hybridize in the wild (Stone et al., ; Grauke et al., ). Suspected hybrid trees in our study were examined by LJ Grauke (USDA‐ARS) and excluded from analyses if confirmed as hybrids.…”

Section: Methodsmentioning

confidence: 99%

Host‐associated differentiation in a pecan and water hickory Aphidomorpha community

Medina

Dickey

Harrison

2017

Entomologia Exp Applicata

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Host‐associated differentiation (HAD) is the formation of genetically distinct, host‐associated populations created and maintained by ecologically mediated reproductive isolation. HAD potentially accounts for species origins in parasites, including herbivorous insects. Although case studies testing the occurrence of HAD are accumulating, it is still unclear how common HAD is and which specific ecological traits explain its occurrence. To address these issues, studies are needed that include negative results (i.e., instances in which parasite populations do not exhibit HAD) and test for HAD across communities (i.e., several parasite species on the same set of host species). In this study, HAD was tested in a community of six species of Aphidomorpha (Hemiptera) that share a host‐plant pair: pecan [Carya illinoinensis (Wangenh.) K.Koch] and water hickory [Carya aquatica (F.Michx) Nutt., both Juglandaceae] trees. All six species are parthenogenetic and three species are endophagous, traits that can exacerbate host‐specific selection. AFLP markers were employed to detect the presence of genetically distinct, host‐associated populations for each insect species. Strict HAD (i.e., the occurrence of genetically distinct pecan‐associated and water hickory‐associated genotypes) was found in Phylloxera notabilis Pergande (Phylloxeridae), Phylloxera devastatrix Pergande, and Monelliopsis pecanis Bissel (Aphididae). Monellia caryella Fitch (Aphididae) displayed a pattern of partial HAD (i.e., the occurrence of only a genetically distinct pecan‐associated genotype). No HAD was found in Melanocallis caryaefoliae Davis (Aphididae) or Phylloxera texana Stoetzel. The pattern of HAD occurrence in the pecan and water hickory Aphidomorpha community indicated that neither parthenogenesis nor endophagy sufficiently explain the occurrence of HAD in this system.

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Morphological and Chemical Evidence on the Hybrid Nature of Bitter Pecan, Carya x Lecontei

Cited by 11 publications

References 16 publications

Testing host‐associated differentiation in a quasi‐endophage and a parthenogen on native trees

Testing host‐associated differentiation in a quasi‐endophage and a parthenogen on native trees

Differences in bacterial diversity of host-associated populations of Phylloxera notabilis Pergande (Hemiptera: Phylloxeridae) in pecan and water hickory

Host‐associated differentiation in a pecan and water hickory Aphidomorpha community

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