Spatially aggregated parasitism on pea aphids, Acyrthosiphon pisum, caused by random foraging behavior of the parasitoid Aphidius ervi

Oikos ◽  
2000 ◽  
Vol 91 (1) ◽  
pp. 66-76 ◽  
Author(s):  
Anders C. Olson ◽  
Anthony R. Ives ◽  
Kevin Gross
PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241870
Author(s):  
Kathryn S. Ingerslew ◽  
Deborah L. Finke

Understanding the factors that influence predator-prey dynamics requires an investigation of oscillations in predator and prey population sizes over time. However, empirical studies are often performed over one or fewer predator generations. This is particularly true for studies addressing the non-consumptive effects of predators on prey. In a previous study that lasted less than one predator generation, we demonstrated that two species of parasitoid wasps additively suppressed aphid populations through a combination of consumptive and non-consumptive effects. However, the non-consumptive effects of one wasp reduced the reproductive success of the other, suggesting that a longer-term experiment may have revealed antagonism between the wasps. The goal of our current study is to evaluate multi-generation consumptive and non-consumptive interactions between pea aphids (Acyrthosiphon pisum) and the wasps Aphidius ervi and Aphidius colemani. Aphidius ervi is a common natural enemy of pea aphids. Aphidius colemani is a non-consumptive enemy that does not consume pea aphids, but negatively affects pea aphid performance through behavioral disturbance. Large field cages were installed to monitor aphid abundance in response to the presence and absence of both species of wasp over four weeks (two parasitoid generations). We found that the non-consumptive enemy A. colemani initially controlled the pea aphid population, but control in the absence of parasitism was not sustainable over the long term. Aphidius ervi suppressed pea aphids through a combination of consumptive and non-consumptive effects. This suppression was more effective than that of A. colemani, but aphid abundance fluctuated over time. Suppression by A. ervi and A. colemani together was complementary, leading to the most effective and stable control of pea aphids. Therefore, promoting a diverse natural enemy community that contributes to pest control through consumptive and non-consumptive interactions may enhance the stability of herbivore population suppression over time.


2020 ◽  
Vol 287 (1929) ◽  
pp. 20200562
Author(s):  
A. H. C. McLean ◽  
J. Hrček ◽  
B. J. Parker ◽  
H. Mathé-Hubert ◽  
H. Kaech ◽  
...  

Many microbial symbionts have multiple phenotypic consequences for their animal hosts. However, the ways in which different symbiont-mediated phenotypes combine to affect fitness are not well understood. We investigated whether there are correlations between different symbiont-mediated phenotypes. We used the symbiont Spiroplasma , a striking example of a bacterial symbiont conferring diverse phenotypes on insect hosts. We took 11 strains of Spiroplasma infecting pea aphids ( Acyrthosiphon pisum ) and assessed their ability to provide protection against the fungal pathogen Pandora neoaphidis and the parasitoids Aphidius ervi and Praon volucre . We also assessed effects on male offspring production for five of the Spiroplasma strains. All but one of the Spiroplasma strains provided very strong protection against the parasitoid P. volucre . As previously reported, variable protection against P. neoaphidis and A. ervi was also present; male-killing was likewise a variable phenotype. We find no evidence of any correlation, positive or negative, between the different phenotypes, nor was there any evidence of an effect of symbiont phylogeny on protective phenotype. We conclude that multiple symbiont-mediated phenotypes can evolve independently from one another without trade-offs between them.


2011 ◽  
Vol 47 (No. 1) ◽  
pp. 25-36 ◽  
Author(s):  
M. Seidenglanz ◽  
I. Huňady ◽  
J. Poslušná ◽  
A.-K. Løes

Occurrences of pea aphids and their natural enemies (syrphids, mummies caused by entomopathogenic fungi Beauveria sp. and by the parasitic wasp Aphidius ervi) were compared in monocultures and mixtures of field peas and spring cereals in three seasons (2008–2010). At the beginning of colonisation, the occurrence of aphids was not substantially influenced by intercropping with cereals. However, the numbers of pea aphids located on inflorescences started to decline earlier in mixtures compared with monoculture. More syrphids (eggs + larvae) were found in mixtures than in monoculture, and more syrphid eggs were found in young aphid colonies (10 to 20 individuals) in mixtures. Intercropping did not influence the occurrence of fungal mummies (Beauveria sp.), but mixtures tended to have more aphid colonies infested by A. ervi in 2008 and 2009.  


BMC Genomics ◽  
2014 ◽  
Vol 15 (1) ◽  
pp. 342 ◽  
Author(s):  
Dominique Colinet ◽  
Caroline Anselme ◽  
Emeline Deleury ◽  
Donato Mancini ◽  
Julie Poulain ◽  
...  

Behaviour ◽  
2021 ◽  
pp. 1-21
Author(s):  
Rosalind K. Humphreys ◽  
Graeme D. Ruxton ◽  
Alison J. Karley

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.


1986 ◽  
Vol 118 (6) ◽  
pp. 601-607 ◽  
Author(s):  
G.A. Maiteki ◽  
R.J. Lamb ◽  
S.T. Ali-Khan

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.


1999 ◽  
Vol 154 (6) ◽  
pp. 652-673 ◽  
Author(s):  
Anthony R. Ives ◽  
Shon S. Schooler ◽  
Victoria J. Jagar ◽  
Sarah E. Knuteson ◽  
Miodrag Grbic ◽  
...  

1991 ◽  
Vol 123 (6) ◽  
pp. 1229-1237 ◽  
Author(s):  
B. Bai

AbstractConspecific host discrimination and larval competition in two aphid parasitoid species were studied in the laboratory using the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), as a host. Aphidius ervi Haliday (Hymenoptera: Aphidiidae) used internal host cues to discriminate between unparasitized and conspecific parasitized hosts. When only parasitized hosts were available, females oviposited into recently parasitized ones where their progeny had a good chance to survive, but rejected those parasitized ≥24 h earlier where their offspring normally died. Competitions occurred only after both eggs had hatched. Larvae eliminated supernumeraries by means of physical combat and physiological suppression. In Aphelinus asychis Walker (Hymenoptera: Aphelinidae), factors, or changes in host internal condition, associated with hatching of the first egg resulted in suppression of conspecific competitors which could be in either larval or egg stage. The older larvae always won competitions through physiological means. A wasp’s oviposition decision is shown to be influenced by the probability of its progeny’s survival. Species that have different reproductive strategies may respond differently to identical host conditions.


1992 ◽  
Vol 124 (1) ◽  
pp. 87-95 ◽  
Author(s):  
K.L. Kouamé ◽  
M. Mackauer

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.


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