scholarly journals Post-reproductive parthenogenetic pea aphids (Acyrthosiphon pisum) are visually identifiable and disproportionately positioned distally to clonal colonies

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2631
Author(s):  
Erik T. Saberski ◽  
Julia Daisy Diamond ◽  
Nathaniel Fath Henneman ◽  
Daniel A. Levitis
Keyword(s):  
Kin Selection ◽  
Acyrthosiphon Pisum ◽  
Model Organisms ◽  
Major Step ◽  
Natural Habitats ◽  
Optimal Method ◽  
Early Results ◽  
Pea Aphids ◽  
Reproductive Life ◽  
Close Relatives

The role of kin-selection in the evolution of post-reproductive life is controversial. While anthropological and demographic studies strongly suggest that humans and a few other species experience kin selection for significant post-reproductive survival, these results are necessarily correlational. Understanding could therefore be advanced by the development of a globally available, field and laboratory tractable experimental model of kin-selected post-reproductive survival. In only one invertebrate (Quadrartus yoshinomiyai, a gall-forming aphid endemic to Japan) have individuals too old to reproduce been shown to be both numerous in natural habitats and able to help close relatives survive or reproduce. Pea aphids, (Acyrthosiphon pisum), common, tractable organisms, frequently outlive their reproductive ages in laboratories, live in tight interacting groups that are often clonal, and therefore should be evaluated as potential model organisms for the study of adaptive post-reproductive life. The first major step in this process is to identify an optimal method for assessing if a parthenogenetic adult is post-reproductive. We evaluated three methods, relying respectively on isolation in clip cages, visual examination for embryonic eyespots, and dissection. In every case each method identified the same individuals as reproductive versus post-reproductive. While the clip-cage method requires a multi-day wait to produce data, and dissection is inevitably fatal, the eyespot method is quick (under one minute per individual) easy, and non-invasive. This method makes it possible to accurately assess the post-reproductive status of a large number of parthenogenetic pea aphids. We demonstrate the usefulness of the eyespot method in showing that while reproductively valuable adults tend to place themselves near the centers of clonal colonies, less valuable post-reproductive adults are more often at or beyond the edges of colonies. These encouraging early results provide both impetuous and aid for further investigations into the post-reproductive lives of pea aphids.

scholarly journals Drop when the stakes are high: adaptive, flexible use of dropping behaviour by aphids

Behaviour ◽  
2021 ◽  
pp. 1-21
Author(s):  
Rosalind K. Humphreys ◽  
Graeme D. Ruxton ◽  
Alison J. Karley
Keyword(s):  
Host Plant ◽  
Acyrthosiphon Pisum ◽  
Adalia Bipunctata ◽  
Macrosiphum Euphorbiae ◽  
Herbivorous Insects ◽  
Chrysoperla Carnea ◽  
Pea Aphids ◽  
Potato Aphids ◽  
Antipredator Defence

Abstract For herbivorous insects, dropping from the host plant is a commonly-observed antipredator defence. The use of dropping compared to other behaviours and its timing in relation to contact with a predator was explored in both pea aphids (Acyrthosiphon pisum) and potato aphids (Macrosiphum euphorbiae). Pea aphids dropped more frequently in response to ladybird adults (Adalia bipunctata) than lacewing larvae (Chrysoperla carnea). Potato aphids mainly walked away or backed-up in response to both predator types; but they dropped more frequently relative to other non-walking defences when faced with ladybird adults. Contact with a predator was an important influencer of dropping for both species, and most drops occurred from adjacent to the predator. Dropping appears to be a defence adaptively deployed only when the risk of imminent predation is high; factors that increase dropping likelihood include presence of faster-foraging predators such as adult ladybirds, predator proximity, and contact between aphid and predator.

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.

scholarly journals Fish functional groups in a tropical wetland of the Yucatan Peninsula, Mexico

2016 ◽  
Vol 14 (2) ◽  
Author(s):  
Fernando Córdova-Tapia ◽  
Luis Zambrano
Keyword(s):  
Functional Groups ◽  
Functional Group ◽  
Group Structure ◽  
Environmental Filtering ◽  
Dry Season ◽  
Freshwater Wetland ◽  
Wet Season ◽  
Major Step ◽  
Natural Habitats ◽  
Niche Complementarity

ABSTRACT The characterization of species' functional traits is a major step in the understanding and description of communities in natural habitats. The classification of species into functional groups is a useful tool to identify redundancy and uniqueness. We studied the fish community of a pristine freshwater wetland in the Sian Ka'an Biosphere Reserve by analysing two multidimensional functions: food acquisition and locomotion. We investigated changes in the functional group structure between habitats (permanent and temporary pools) and seasons (dry and wet). Six functional groups with different ecological characteristics were detected, two of which had high functional redundancy and three of them were represented by single species with unique ecological functions. In permanent pools during the dry season, functional group richness and diversity were lower, while evenness was higher. During the wet season, all functional groups were detected and similar functional group structure was found between habitats. These results suggest an effect of environmental filtering during the dry season and niche complementarity during the wet season.

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.

Extraordinary proliferation of microorganisms in aposymbiotic pea aphids, Acyrthosiphon pisum

2003 ◽  
Vol 82 (3) ◽  
pp. 152-161 ◽  
Author(s):  
Atsushi Nakabachi ◽  
Hajime Ishikawa ◽  
Toshiaki Kudo
Keyword(s):  
Acyrthosiphon Pisum ◽  
Pea Aphids

Marking aphids with rubidium

1974 ◽  
Vol 52 (9) ◽  
pp. 1135-1136 ◽  
Author(s):  
B. D. Frazer ◽  
D. A. Raworth
Keyword(s):  
Atomic Absorption ◽  
Acyrthosiphon Pisum ◽  
Broad Bean ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Spectrophotometry ◽  
Bean Plants ◽  
Pea Aphids ◽  
Vicia Faba L ◽  
Source Plant ◽  
Nutrient Solutions

Pea aphids (Acyrthosiphon pisum (Harris)) were marked with rubidium by rearing them on broad bean plants (Vicia faba L.) maintained in nutrient solutions that contained rubidium chloride. Rb+ was readily detected by atomic absorption spectrophotometry in groups of aphids, and it varied in concentration with the concentration in the plant. A technique was developed for the preparation and analysis of single aphids marked with Rb+. More than 77% of the Rb+ in marked adult aphids was lost within 2 days of leaving the source plant, but detectable quantities remained for 4 days.

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