scholarly journals Host-instar selection in the aphid parasitoid Monoctonus paulensis (Hymenoptera: Braconidae, Aphidiinae): a preference for small pea aphids

2000 ◽  
Vol 97 (3) ◽  
pp. 347-353 ◽  
Author(s):  
Amanda CHAU ◽  
Manfred MACKAUER
Keyword(s):  
Aphid Parasitoid ◽  
Host Instar ◽  
Pea Aphids

Host–instar selection in the aphid parasitoid Monoctonus paulensis (Hymenoptera: Braconidae, Aphidiinae): assessing costs and benefits

2001 ◽  
Vol 133 (4) ◽  
pp. 549-564 ◽  
Author(s):  
Amanda Chau ◽  
Manfred Mackauer
Keyword(s):  
Body Size ◽  
Acyrthosiphon Pisum ◽  
Search Time ◽  
Pea Aphid ◽  
Potential Fecundity ◽  
Aphid Parasitoid ◽  
Offspring Number ◽  
Host Instar ◽  
Parasitoid Development ◽  
Pupal Mortality

AbstractFemales of Monoctonus paulensis (Ashmead), a solitary parasitoid of aphids, generally select the relatively smaller over equally available larger instars of the pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphidoidea: Aphididae). Large hosts contain more resources for parasitoid development and hence have presumably higher quality; however, they require more time to subdue and are more likely to escape. We tested the hypothesis that a female’s choice among first (L1), second (L2), third (L3), and fourth (L4) instars of the pea aphid is based on the optimal balance between fitness costs in terms of time and fitness gains in terms of offspring number and size. Prepupal mortality did not vary with host instar, but pupal mortality was greater among parasitoids developing in L4 than in any younger instars. Offspring mortality was not influenced by clutch size in that mortality risk did not differ between parasitoids developing alone and counterparts developing in a clutch. The sex ratio, measured as proportion of daughters among offspring, was female-biased on all four host instars; the degree of bias increased from 0.70 (in L1) to 0.92 (in L4). Parasitoid body size was a function of aphid size at parasitism. Females were larger than males; the magnitude of the difference in body size was constant and independent of host and hence parasitoid size. A female’s potential fecundity as measured by the number of ovarial eggs at eclosion varied with her size and larval ontogeny. The four instars of the pea aphid were ranked in the order L1 > L2 > L3 > L4 both in terms of the number of offspring produced per encountered host and in terms of a female’s time costs; first instars are easier to handle and are more abundant in the field than older instars. The four host types were ranked in the order L2 > L3 > L1 > L4 in terms of the proportion and potential fecundity of daughters among offspring. The observed preference pattern (L1 > L2 > L3 > L4) suggests that, in choosing hosts, females of M. paulensis maximize the number of offspring per unit of search time rather than simply offspring quality.

INFLUENCE OF PLANT QUALITY ON INTERACTIONS BETWEEN THE APHID PARASITOID EPHEDRUS CALIFORNICUS BAKER (HYMENOPTERA: APHIDIIDAE) AND ITS HOST, ACYRTHOSIPHON PISUM (HARRIS) (HOMOPTERA: APHIDIDAE)

1996 ◽  
Vol 128 (1) ◽  
pp. 27-39 ◽  
Author(s):  
B. Stadler ◽  
M. Mackauer
Keyword(s):  
Life History ◽  
Acyrthosiphon Pisum ◽  
Dry Mass ◽  
Growth Potential ◽  
Plant Quality ◽  
Life History Strategies ◽  
Mass Rate ◽  
Aphid Parasitoid ◽  
Pea Aphids ◽  
The Individual

AbstractWe determined variations in selected life-history parameters in a tritrophic system that consisted of a plant (broad bean, Vicia faba L.), an aphid (pea aphid, Acyrthosiphon pisum), and an aphid parasitoid (Ephedras californicus). We manipulated plant and aphid quality by growing bean plants in a high- and a low-quality nutrient solution for three generations. Pea aphids adapted to reduced nutrient availability by differentially allocating resources to somatic and gonadal growth across generations. On low-quality plants, time from birth to adult increased and dry mass decreased. The number of sclerotized embryos was correlated with adult dry mass. By contrast, in E. californicus, variations in dry mass, rate of development, and number of ovarial eggs did not suggest transgenerational adaptations to resource quality as measured by aphid size. The number of mature eggs was dependent on female age. Development time varied with parasitoid sex and was independent of aphid stage at the time of death. In the low-quality treatment, males survived on average longer than females eclosing from the same kinds of hosts.Aphids and their parasitoids have evolved flexible life-history strategies in response to variations in plant quality. Pea aphids adapted to qualitatively variable resources by optimizing the balance between somatic and gonadal investment across successive generations. But E. californicus responded to low host quality at the level of the individual, rather than across generations; the trade-off pattern was influenced by the host’s growth potential after parasitization.

scholarly journals Serratia symbiotica Enhances Fatty Acid Metabolism of Pea Aphid to Promote Host Development

2021 ◽  
Vol 22 (11) ◽  
pp. 5951
Author(s):  
Xiaofei Zhou ◽  
Xiaoyu Ling ◽  
Huijuan Guo ◽  
Keyan Zhu-Salzman ◽  
Feng Ge ◽  
...  
Keyword(s):  
Body Weight ◽  
Fatty Acid ◽  
Myristic Acid ◽  
Fatty Acid Synthase ◽  
Fatty Acid Biosynthesis ◽  
Acid Biosynthesis ◽  
Pea Aphids ◽  
Serratia Symbiotica ◽  
Aphid Host ◽  
Host Development

Bacterial symbionts associated with insects are often involved in host development and ecological adaptation. Serratia symbiotica, a common facultative endosymbiont harbored in pea aphids, improves host fitness and heat tolerance, but studies concerning the nutritional metabolism and impact on the aphid host associated with carrying Serratia are limited. In the current study, we showed that Serratia-infected aphids had a shorter nymphal developmental time and higher body weight than Serratia-free aphids when fed on detached leaves. Genes connecting to fatty acid biosynthesis and elongation were up-regulated in Serratia-infected aphids. Specifically, elevated expression of fatty acid synthase 1 (FASN1) and diacylglycerol-o-acyltransferase 2 (DGAT2) could result in accumulation of myristic acid, palmitic acid, linoleic acid, and arachidic acid in fat bodies. Impairing fatty acid synthesis in Serratia-infected pea aphids either by a pharmacological inhibitor or through silencing FASN1 and DGAT2 expression prolonged the nymphal growth period and decreased the aphid body weight. Conversely, supplementation of myristic acid (C14:0) to these aphids restored their normal development and weight gain. Our results indicated that Serratia promoted development and growth of its aphid host through enhancing fatty acid biosynthesis. Our discovery has shed more light on nutritional effects underlying the symbiosis between aphids and facultative endosymbionts.

scholarly journals Bacterial Communities Associated with Host-Adapted Populations of Pea Aphids Revealed by Deep Sequencing of 16S Ribosomal DNA

PLoS ONE ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. e0120664 ◽  
Author(s):  
Jean-Pierre Gauthier ◽  
Yannick Outreman ◽  
Lucie Mieuzet ◽  
Jean-Christophe Simon
Keyword(s):  
Deep Sequencing ◽  
Ribosomal Dna ◽  
Bacterial Communities ◽  
16S Ribosomal Dna ◽  
Pea Aphids

scholarly journals Transmission of a Protease-Secreting Bacterial Symbiont Among Pea Aphids via Host Plants

2019 ◽  
Vol 10 ◽  
Author(s):  
Marisa Skaljac ◽  
Heiko Vogel ◽  
Natalie Wielsch ◽  
Sanja Mihajlovic ◽  
Andreas Vilcinskas
Keyword(s):  
Host Plants ◽  
Bacterial Symbiont ◽  
Pea Aphids

Honeydew as a source of host-searching kairomones for the aphid parasitoid Aphidius nigripes (Hymenoptera: Aphidiidae)

1984 ◽  
Vol 62 (8) ◽  
pp. 1513-1520 ◽  
Author(s):  
Yves Bouchard ◽  
Conrad Cloutier
Keyword(s):  
Filter Paper ◽  
Initial Response ◽  
Response Level ◽  
Aphid Parasitoid ◽  
Potato Plants ◽  
Treated Area ◽  
Aphidius Nigripes ◽  
Locomotory Behavior ◽  
High Concentrations ◽  
Aphid Honeydew

The parasitoid Aphidius nigripes spent more time searching on potato plants previously infested with aphids than on fresh plants, suggesting the presence of searching stimulants on infested plants. Water extracts of aphid honeydew applied to the surface of foliage or to filter paper discs increased searching time and affected the locomotory behavior of parasitoids. When crossing a honeydew-treated area on filter paper, female parasitoids exhibited arrestment, antennal examination, abdominal protraction, reduced walking speed, and increased turning. Upon losing contact with honeydew-contaminated substrate, parasitoids often exhibited a klinotactic response which drove them back to the treated area. The time spent by individual parasitoids within a honeydew-treated area on filter paper decreased with successive visits, but the initial response level was restored when the insect was prevented from contacting honeydew for 1 h. The retention response exhibited by parasitoids contacting a honeydew-treated area increased with honeydew concentration, but levelled off at high concentrations. Naive parasitoids were more responsive to the retention effect of honeydew than experienced individuals.

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