Induction of winged sexuparae in root-inhabiting colonies of the aphid Pemphigus betae

1993 ◽  
Vol 18 (3) ◽  
pp. 296-302 ◽  
Author(s):  
NANCY MORAN ◽  
JEFFREY SEMINOFF ◽  
LAUREL JOHNSTONE
Keyword(s):  
1958 ◽  
Vol 90 (7) ◽  
pp. 439-440 ◽  
Author(s):  
A. M. Harper

Normally the sugar-beet root aphid, Pemphigus betae Doane, lives and feeds on sugar-beet roots below ground during the summer and fall. However, in many beet fields between Lethbridge and Monarch, Alberta, in September, 1956, a large number of these aphids were found on the soil surface and on the crowns and leaves of the plants. Many of the aphids had crawled up the plants and, even after death, remained clinging to the leaves (Fig. 1). This clinging reaction seemed similar to that of grasshoppers infected with Entomophthora grylli Fresen. Mr. R. B. Baird, Entomology Laboratory, Canada Department of Agriculture, Belleville, Ontario, identified the organism causing the disease destroying these aphids as Entomophthora aphidis Hoffm. This is the first record of this disease killing subterranean aphids in Canada. The only other reports of E. aphidis on root aphids are those of Maxson (1916) in Colorado and Charles (1941) in California. In Canada, it has been previously reported as a factor in control of the pea aphid, Acyrthosiphon pisum (Harr.), in the Annapolis Valley, Nova Scotia (MacLeod, 1953).


2017 ◽  
Vol 284 (1854) ◽  
pp. 20162703 ◽  
Author(s):  
Arthur R. Keith ◽  
Joseph K. Bailey ◽  
Matthew K. Lau ◽  
Thomas G. Whitham

We examined the hypothesis that genetics-based interactions between strongly interacting foundation species, the tree Populus angustifolia and the aphid Pemphigus betae , affect arthropod community diversity, stability and species interaction networks of which little is known. In a 2-year experimental manipulation of the tree and its aphid herbivore four major findings emerged: (i) the interactions of these two species determined the composition of an arthropod community of 139 species; (ii) both tree genotype and aphid presence significantly predicted community diversity; (iii) the presence of aphids on genetically susceptible trees increased the stability of arthropod communities across years; and (iv) the experimental removal of aphids affected community network structure (network degree, modularity and tree genotype contribution to modularity). These findings demonstrate that the interactions of foundation species are genetically based, which in turn significantly contributes to community diversity, stability and species interaction networks. These experiments provide an important step in understanding the evolution of Darwin's ‘entangled bank’, a metaphor that characterizes the complexity and interconnectedness of communities in the wild.


1959 ◽  
Vol 91 (11) ◽  
pp. 680-685 ◽  
Author(s):  
A. M. Harper

In southern Alberta there are several species of aphids that produce galls on poplar trees (Harper, 1959). These aphids are all in the subfamily Eriosomatinae and in the genera Pemphigus Hartig, Thecabius Koch, and Mordwilkoja Del. G. Two of the species are of economic importance, Pemphigus betae Doane, a pest of sugar beets in Alberta and parts of United States (Harper, 1957; Maxson, 1916; Parker, 1915), and Pemphigus populitransversus Riley, a serious pest of crucifers in Texas (Wene and White, 1953). Both species overwinter on poplar as eggs. In spring the fundatrix emerges from the egg and feeds on the poplar leaf, initiating a gall in which the winged fundatrigeniae are produced. During the summer the fundatrigeniae migrate to the secondary host where they produce the wingless alienicolae; in the fall these in turn produce the winged sexuparae, which migrate to the poplars where they produce the wingless sexuales. The female sexuales, after mating, deposit eggs on the poplars to complete the life cycle (Harper, 1957; Jones and Gillette, 1918; Parker, 1914).


2019 ◽  
Vol 32 (6) ◽  
pp. 654-672 ◽  
Author(s):  
Mélanie J. A. Body ◽  
Matthew S. Zinkgraf ◽  
Thomas G. Whitham ◽  
Chung-Ho Lin ◽  
Ryan A. Richardson ◽  
...  

Insect galls are highly specialized structures arising from atypical development of plant tissue induced by insects. Galls provide the insect enhanced nutrition and protection against natural enemies and environmental stresses. Galls are essentially plant organs formed by an intimate biochemical interaction between the gall-inducing insect and its host plant. Because galls are plant organs, their development is likely to be governed by phytohormones involved in normal organogenesis. We characterized concentrations of both growth and defensive phytohormones in ungalled control leaves and galls induced by the aphid Pemphigus betae on narrowleaf cottonwood Populus angustifolia that differ genotypically in resistance to this insect. We found that susceptible trees differed from resistant trees in constitutive concentrations of both growth and defense phytohormones. Susceptible trees were characterized by significantly higher constitutive cytokinin concentrations in leaves, significantly greater ability of aphids to elicit cytokinin increases, and significantly lower constitutive defense phytohormone concentrations than observed in resistant trees. Phytohormone concentrations in both constitutive and induced responses in galled leaves exhibited high broad-sense heritability that, respectively, ranged from 0.39 to 0.93 and from 0.28 to 0.66, suggesting that selection can act upon these traits and that they might vary across the landscape. Increased cytokinin concentrations may facilitate forming strong photosynthate sinks in the galls, a requirement for galling insect success. By characterizing for the first time the changes in 15 phytohormones belonging to five different classes, this study offers a better overview of the signaling alteration occurring in galls that has likely been important for their ecology and evolution. [Formula: see text] Copyright © 2019 The Author(s). This is an open-access article distributed under the CC BY-NC-ND 4.0 International license .


1963 ◽  
Vol 95 (8) ◽  
pp. 863-873 ◽  
Author(s):  
A. M. Harper

AbstractIn southern Alberta the fundatrix of P. betae hatches from the overwintered egg in late April and early May and feeds on an emerging leaf of P. angustifolia or P. balsamifera, forming a gall. In the gall it produces alate fundatrigeniae, which migrate from the poplars to beets and produce apterous alienicolae. This form of the aphid reduces both yield and sugar content of beet roots. During the summer several generations of alienicolae are produced. In the fall most of the alienicolae produce sexuparae. These migrate from beets to poplars, where they produce males and oviparae. Each fertilized ovipara lays a single egg on the bark of a poplar tree. The species may overwinter as eggs on the poplars or as alienicolae in the soil. The egg has an obligatory diapause that is terminated by exposure to low temperature. The fungatrigeniae migrate from late June to mid-August and the sexuparae from early September to late October. The potential reproductive capacities of the fundatrix, fundatrigenia, sexupara, and ovipara averaged 163, 13, 6, and 1, respectively. Under greenhouse conditions 20 aphids (alienicolae) produced 9,000 in 6 weeks when the soil temperature was maintained at 27 °C. Below 15 °C. the rate of reproduction was low and death was caused by exposure to 30 °C. for 6 weeks. The most important predators of P. betae were the anthocorid A. antevolens, the flies S. bigelowi, L. pemphigae and T. glabra, and a coccinellid Scymnus sp.


1936 ◽  
Vol 68 (8) ◽  
pp. 170-177
Author(s):  
Curtis W. Sabrosky

Some recently discovered changes in nomenclature led to the preparation of a synopsis of the Nearctic species of Chloropisca, which is presented with notes upon the distribution as checked by the writer and a key to the eleven known species. Chloropisca sulfurifrons Duda is included with some doubt.It is rather remarkable that among a group as common as Chloropisca so little is known regarding the life history and habits. Chloropisca glabra is the only species in which the life history is well known. Its larvae are predaceous upon root aphids,and are especially important predators of the sugar beet root aphis, Pemphigus betae Doane.


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