Pea aphid, Acyrthosiphon pisum, cornicle ontogeny as an adaptation to differential predation risk

2002 ◽  
Vol 80 (12) ◽  
pp. 2131-2136 ◽  
Author(s):  
Edward B Mondor ◽  
Bernard D Roitberg
Keyword(s):  
Alarm Pheromone ◽  
Acyrthosiphon Pisum ◽  
Harmonia Axyridis ◽  
Inclusive Fitness ◽  
Pea Aphid ◽  
Body Parts ◽  
Anatomical Structures ◽  
Alarm Signaling ◽  
Risk Of Predation ◽  
Pea Aphids

Aphids possess unique anatomical structures called cornicles through which a defensive secretion containing alarm pheromone is often emitted when a predator attacks an aphid. The levels of alarm pheromone in cornicle droplets from the pea aphid, Acyrthosiphon pisum (Harris), vary considerably during development; however, it is not clear how the length of the cornicle changes during ontogeny. The length of the cornicle relative to the lengths of other body structures may have profound effects on aphid defense and alarm signal diffusion. Using previously published morphological measurements of pea aphids and observing interactions between pea aphids and multicolored Asian ladybird beetles, Harmonia axyridis Pallas, it was observed that pea aphid cornicles elongate proportionally more than other body parts during the first four instars, when alarm-pheromone levels have peaked, than during the fifth (adult) instar, when pheromone levels decline. Pea aphids also are more likely to emit cornicle droplets and daub them onto a predator when the cornicles are undergoing such rapid growth. We suggest that because of a high risk of predation, rapid cornicle growth in juveniles has evolved both for individual defense and for the inclusive fitness benefits of alarm signaling.

Escape behaviour of the pea aphid Acyrthosiphon pisum (Harris) in response to alarm pheromone and vibration

1982 ◽  
Vol 60 (10) ◽  
pp. 2245-2252 ◽  
Author(s):  
J. M. Clegg ◽  
C. A. Barlow
Keyword(s):  
Host Plant ◽  
Alarm Pheromone ◽  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Escape Behaviour ◽  
Pea Aphids ◽  
Escape Responses

Pea aphids respond most effectively to the threat of a predator by walking away or dropping from their host plant. Simulating threat by using vibration and alarm pheromone, both separately and together, we found no evidence that escape responses are heritable, nor that individual aphids have characteristic escape behaviours. On the contrary, the amount of alarm pheromone influenced responses: the more pheromone, the more likely an immediate and effective escape. Vibration preceding alarm pheromone greatly increased responsiveness to pheromone, and aphids were more responsive to pheromone after vibration when feeding on stems than when feeding on the undersides of leaves.

Adaptation of alarm pheromone responses of the pea aphid Acyrthosiphon pisum (Harris)

1978 ◽  
Vol 56 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Bernard D. Roitberg ◽  
Judith H. Myers
Keyword(s):  
British Columbia ◽  
High Risk ◽  
Host Plant ◽  
Alarm Pheromone ◽  
Acyrthosiphon Pisum ◽  
Fourth Instar ◽  
Pea Aphid ◽  
Vibratory Stimulus ◽  
Ground Temperatures ◽  
Pea Aphids

Adult and fourth-instar pea aphids from Vancouver, B.C., responded to alarm pheromone by either dropping, running, or backing up. Younger instars showed almost no response to pheromone but all instars responded to a pheromone–vibratory stimulus, usually by dropping. We suggest that younger instars respond conservatively to alarm pheromone because they are less agile on the ground and are more likely to die there before finding a suitable food plant. Adult and fourth-instar aphids from the hot, dry region of British Columbia do not respond to alarm pheromone by dropping. This is due to the high risk associated with any instar leaving the host plant where ground temperatures and evaporation rates are high.Clones of aphids contained both individuals which do and do not drop in response to pheromone stimulus. This mixture of behaviour types allows part of the group to exploit new resources while others remain on a known resource.

SEASONAL ABUNDANCE OF THE PEA APHID, ACYRTHOSIPHON PISUM (HOMOPTERA: APHIDIDAE), IN MANITOBA FIELD PEAS

1986 ◽  
Vol 118 (6) ◽  
pp. 601-607 ◽  
Author(s):  
G.A. Maiteki ◽  
R.J. Lamb ◽  
S.T. Ali-Khan
Keyword(s):  
Pisum Sativum ◽  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Seasonal Abundance ◽  
Economic Threshold ◽  
Field Peas ◽  
Pea Aphids

AbstractPea aphids, Acyrthosiphon pisum (Harris), were sampled from 1980 to 1983 in field peas, Pisum sativum (L.), in Manitoba. Sweep and foliage samples were taken in commercial fields and plots. Aphids were found in late May or early June soon after the crop emerged, but populations were low throughout June. Populations increased in July, when the crop was flowering and producing pods, and peaked in the latter half of July or early August in 3 of the 4 years, when pods were maturing. Populations decreased rapidly after the peak, as the plants senesced. In 1980, a drought year, aphid densities were low and the populations peaked in the middle of August. From 1981 to 1983, densities exceeded the economic threshold in all commercial fields and all but one of the plots that were sampled.

Age-dependent fitness costs of alarm signaling in aphids

2003 ◽  
Vol 81 (5) ◽  
pp. 757-762 ◽  
Author(s):  
Edward B Mondor ◽  
Bernard D Roitberg
Keyword(s):  
Alarm Pheromone ◽  
Fourth Instar ◽  
Fitness Cost ◽  
Fitness Costs ◽  
Alarm Signal ◽  
Offspring Production ◽  
Direct Fitness ◽  
Alarm Signaling ◽  
Pea Aphids ◽  
Age Dependent

For an alarm signal to evolve, the benefits to the signaler must outweigh the costs of sending the signal. Research has largely focused on the benefits of alarm signaling, and the costs to an organism of sending an alarm signal are not well known. When attacked by a predator, aphids secrete cornicle droplets, containing an alarm pheromone, for individual protection and to warn clonemates. As aphid alarm pheromone is synthesized de novo in a feedback loop with juvenile hormone, we hypothesized that the secretion of cornicle droplets may result in a direct fitness cost to the emitter. We show that the secretion of a single cornicle droplet by pre-reproductive (third- and fourth-instar) pea aphids, Acyrthosiphon pisum, directly altered the timing and number of offspring produced. Third-instar pea aphids delayed offspring production but produced more offspring overall than non-secreting aphids, demonstrating a life-history shift but no significant fitness cost of droplet secretion. Fourth-instar pea aphids also delayed offspring production but produced the same number of offspring as non-secretors, resulting in a direct fitness cost of droplet secretion. Offspring production by adult, reproductive pea aphids that secreted a cornicle droplet did not differ from that of non-secretors. Thus, the fitness costs of secreting cornicle droplets containing an alarm signal are age-dependent.

INFLUENCE OF STARVATION ON DEVELOPMENT AND REPRODUCTION IN APTEROUS VIRGINOPARAE OF THE PEA APHID, ACYRTHOSIPHON PISUM (HARRIS) (HOMOPTERA: APHIDIDAE)

1992 ◽  
Vol 124 (1) ◽  
pp. 87-95 ◽  
Author(s):  
K.L. Kouamé ◽  
M. Mackauer
Keyword(s):  
Vicia Faba ◽  
Acyrthosiphon Pisum ◽  
Reproductive Investment ◽  
Dry Weight ◽  
Pea Aphid ◽  
Nutrient Loss ◽  
Adult Weight ◽  
Pea Aphids ◽  
Wet Weight ◽  
Growth Development

AbstractThe influence of nutrient stress on growth, development, and reproduction in apterous virginoparae of the pea aphid, Acyrthosiphon pisum (Harris), was investigated in the laboratory. We tested the hypothesis that species with a high reproductive investment have low resistance to starvation. Aphids in two groups were starved daily from birth for 4 h and 6 h, respectively, and compared with feeding counterparts reared on leaves of broad beans, Vicia faba L. Aphid wet weight increased as an exponential function of age in all groups. Starved aphids had lower adult weight and required longer from birth to parturition than feeding aphids. These effects increased with the length of daily starvation. The number of offspring produced was correlated with adult dry weight. Aphids were unable to compensate, or to compensate completely, for water and nutrient loss resulting from starvation. It is suggested that pea aphids allocate resources first to maintenance and then to reproduction when deprived of food.

COMPARISON OF SWEEP-NET AND STEM-COUNT TECHNIQUES FOR SAMPLING PEA APHIDS IN ALFALFA

1989 ◽  
Vol 24 (3) ◽  
pp. 344-347
Author(s):  
G. David Buntin ◽  
David J. Isenhour
Keyword(s):  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Density Estimates ◽  
Pea Aphids ◽  
Efficient Alternative ◽  
Highly Correlated ◽  
Sweep Net

The accuracy, precision and efficiency of stem-count and sweep-net techniques were compared for sampling the pea aphid, Acyrthosiphon pisum (Harris), in alfalfa. Density estimates by both techniques were highly correlated (r = 0.87). Both techniques were similar in sample precision and efficiency, but stem counts provided more accurate density estimates than the sweep net technique. The stem count technique is an accurate and efficient alternative to the sweep net for sampling pea aphids in alfalfa.

scholarly journals Real-Time Analysis of Alarm Pheromone Emission by the Pea Aphid (Acyrthosiphon Pisum) Under Predation

2007 ◽  
Vol 34 (1) ◽  
pp. 76-81 ◽  
Author(s):  
Ezra G. Schwartzberg ◽  
Grit Kunert ◽  
Claudia Stephan ◽  
Anja David ◽  
Ursula S. R. Röse ◽  
...  
Keyword(s):  
Real Time ◽  
Alarm Pheromone ◽  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Pheromone Emission

scholarly journals Fate of dietary sucrose and neosynthesis of amino acids in the pea aphid, acyrthosiphon pisum, reared on different diets

1999 ◽  
Vol 202 (19) ◽  
pp. 2639-2652 ◽  
Author(s):  
G. Febvay ◽  
Y. Rahbe ◽  
M. Rynkiewicz ◽  
J. Guillaud ◽  
G. Bonnot
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Acyrthosiphon Pisum ◽  
Specific Activity ◽  
Essential Amino Acids ◽  
Pea Aphid ◽  
Natural Food ◽  
Pea Aphids

The fate of sucrose, the major nutrient of an aphid's natural food, was explored by radiolabeling in the pea aphid Acyrthosiphon pisum. To investigate the influence of nitrogen quality of food on amino acid neosynthesis, pea aphids were reared on two artificial diets differing in their amino acid composition. The first (diet A) had an equilibrated amino acid balance, similar to that derived from analysis of aphid carcass, and the other (diet B) had an unbalanced amino acid composition similar to that of legume phloem sap. Aphids grown on either diet expired the same quantity of sucrose carbon as CO(2), amounting to 25–30 % of the ingested sucrose catabolized in oxidation pathways. On diet A, the aphids excreted through honeydew about twice as much sucrose carbon as on diet B (amounting to 12.6 % of the ingested sucrose for diet A and 8.4 % for diet B), while amounts of sucrose carbons incorporated into exuviae were almost identical (1.9 % of the ingested sucrose on diet A and 2.7 % on diet B). There was also no difference in the amounts of sucrose carbon incorporated into the aphid tissues, which represented close to 50 % of the ingested sucrose. Sucrose carbons in the aphid tissues were mainly incorporated into lipids and the quantities involved were the same in aphids reared on either diet. On diet B, we observed neosynthesis of all protein amino acids from sucrose carbons and, for the first time in an aphid, we directly demonstrated the synthesis of the essential amino acids leucine, valine and phenylalanine. Amino acid neosynthesis from sucrose was significantly higher on diet B (11.5 % of ingested sucrose carbons) than on diet A (5.4 %). On diet A, neosynthesis of most of the amino acids was significantly diminished, and synthesis of two of them (histidine and arginine) was completely suppressed. The origin of amino acids egested through honeydew was determined from the specific activity of the free amino acid pool in the aphid. Aphids are able to adjust to variation in dietary amino acids by independent egestion of each amino acid. While more than 80 % of excreted nitrogen was from food amino acids, different amino acids were excreted in honeydew of aphids reared on the two diets. The conversion yields of dietary sucrose into aphid amino acids determined in this study were combined with those obtained previously by studying the fate of amino acids in pea aphids reared on diet A. The origin of all the amino acid carbons in aphid tissues was thus computed, and the metabolic abilities of aphid are discussed from an adaptive point of view, with respect to their symbiotic status.

scholarly journals The importance of antennae for pea aphid wing induction in the presence of natural enemies

2005 ◽  
Vol 95 (2) ◽  
pp. 125-131 ◽  
Author(s):  
G. Kunert ◽  
W.W. Weisser
Keyword(s):  
Natural Enemies ◽  
Chemical Cues ◽  
Acyrthosiphon Pisum ◽  
Chemical Signals ◽  
Pea Aphid ◽  
Visual Signals ◽  
Wing Formation ◽  
Tactile Stimuli ◽  
Pea Aphids ◽  
General Response

AbstractThe pea aphidAcyrthosiphon pisumHarris has been shown to produce an increasing proportion of winged morphs among its offspring when exposed to natural enemies, in particular hoverfly larvae, lacewing larvae, adult and larval ladybirds and aphidiid parasitoids. While these results suggest that wing induction in the presence of predators and parasitoids is a general response of the pea aphid, the cues and mechanisms underlying this response are still unclear. Tactile stimuli and the perception of chemical signals as well as visual signals are candidates for suitable cues in the presence of natural enemies. In this paper the hypothesis that the aphids' antennae are crucial for the wing induction in the presence of natural enemies is tested. Antennae of pea aphids were ablated and morph production was scored when aphids were reared either in the presence or the absence of predatory lacewing larvae over a six-day period. Ablation of antennae resulted in a drastic drop in the proportion of winged morphs among the offspring, both in the presence and the absence of a predator whereas predator presence increased wing induction in aphids with intact antennae, as reported in previous experiments. The results show that antennae are necessary for wing induction in the presence of natural enemies. Critical re-examination of early work on the importance of aphid antennae and tactile stimuli for wing induction suggests that a combination of tactile and chemical cues is likely to be involved not only in predator-induced wing formation but also for wing induction in response to factors such as crowding in the aphid colony.

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